--- /dev/null
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/apex_driver.c b/drivers/staging/gasket-driver/apex_driver.c
+--- a/drivers/staging/gasket-driver/apex_driver.c 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/apex_driver.c 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,1243 @@
++// SPDX-License-Identifier: GPL-2.0
++/*
++ * Driver for the Apex chip.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++
++#include <linux/atomic.h>
++#include <linux/compiler.h>
++#include <linux/delay.h>
++#include <linux/device.h>
++#include <linux/fs.h>
++#include <linux/init.h>
++#include <linux/mm.h>
++#include <linux/module.h>
++#include <linux/moduleparam.h>
++#include <linux/pci.h>
++#include <linux/printk.h>
++#include <linux/sched.h>
++#include <linux/uaccess.h>
++#include <linux/workqueue.h>
++
++#include "apex.h"
++
++#include "gasket_core.h"
++#include "gasket_interrupt.h"
++#include "gasket_page_table.h"
++#include "gasket_sysfs.h"
++
++/* Constants */
++#define APEX_DEVICE_NAME "Apex"
++#define APEX_DRIVER_VERSION "1.2"
++
++/* CSRs are in BAR 2. */
++#define APEX_BAR_INDEX 2
++
++#define APEX_PCI_VENDOR_ID 0x1ac1
++#define APEX_PCI_DEVICE_ID 0x089a
++
++/* Bar Offsets. */
++#define APEX_BAR_OFFSET 0
++#define APEX_CM_OFFSET 0x1000000
++
++/* The sizes of each Apex BAR 2. */
++#define APEX_BAR_BYTES 0x100000
++#define APEX_CH_MEM_BYTES (PAGE_SIZE * MAX_NUM_COHERENT_PAGES)
++
++/* The number of user-mappable memory ranges in BAR2 of a Apex chip. */
++#define NUM_REGIONS 3
++
++/* The number of nodes in a Apex chip. */
++#define NUM_NODES 1
++
++/*
++ * The total number of entries in the page table. Should match the value read
++ * from the register APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE_SIZE.
++ */
++#define APEX_PAGE_TABLE_TOTAL_ENTRIES 8192
++
++#define APEX_EXTENDED_SHIFT 63 /* Extended address bit position. */
++
++/* Check reset 120 times */
++#define APEX_RESET_RETRY 120
++/* Wait 100 ms between checks. Total 12 sec wait maximum. */
++#define APEX_RESET_DELAY 100
++
++/* Interval between temperature polls, 0 disables polling */
++#define DEFAULT_APEX_TEMP_POLL_INTERVAL 5000
++
++/* apex device private data */
++struct apex_dev {
++ struct gasket_dev *gasket_dev_ptr;
++ struct delayed_work check_temperature_work;
++ u32 adc_trip_points[3];
++ atomic_t temp_poll_interval;
++ u32 hw_temp_warn1_adc;
++ u32 hw_temp_warn2_adc;
++ bool hw_temp_warn1_en;
++ bool hw_temp_warn2_en;
++};
++
++/* Enumeration of the supported sysfs entries. */
++enum sysfs_attribute_type {
++ ATTR_KERNEL_HIB_PAGE_TABLE_SIZE,
++ ATTR_KERNEL_HIB_SIMPLE_PAGE_TABLE_SIZE,
++ ATTR_KERNEL_HIB_NUM_ACTIVE_PAGES,
++ ATTR_TEMP,
++ ATTR_TEMP_WARN1,
++ ATTR_TEMP_WARN1_EN,
++ ATTR_TEMP_WARN2,
++ ATTR_TEMP_WARN2_EN,
++ ATTR_TEMP_TRIP0,
++ ATTR_TEMP_TRIP1,
++ ATTR_TEMP_TRIP2,
++ ATTR_TEMP_POLL_INTERVAL,
++ ATTR_UNIQUE_ID,
++};
++
++/*
++ * Register offsets into BAR2 memory.
++ * Only values necessary for driver implementation are defined.
++ */
++enum apex_bar2_regs {
++ APEX_BAR2_REG_SCU_BASE = 0x1A300,
++ APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE_SIZE = 0x46000,
++ APEX_BAR2_REG_KERNEL_HIB_EXTENDED_TABLE = 0x46008,
++ APEX_BAR2_REG_KERNEL_HIB_TRANSLATION_ENABLE = 0x46010,
++ APEX_BAR2_REG_KERNEL_HIB_INSTR_QUEUE_INTVECCTL = 0x46018,
++ APEX_BAR2_REG_KERNEL_HIB_INPUT_ACTV_QUEUE_INTVECCTL = 0x46020,
++ APEX_BAR2_REG_KERNEL_HIB_PARAM_QUEUE_INTVECCTL = 0x46028,
++ APEX_BAR2_REG_KERNEL_HIB_OUTPUT_ACTV_QUEUE_INTVECCTL = 0x46030,
++ APEX_BAR2_REG_KERNEL_HIB_SC_HOST_INTVECCTL = 0x46038,
++ APEX_BAR2_REG_KERNEL_HIB_TOP_LEVEL_INTVECCTL = 0x46040,
++ APEX_BAR2_REG_KERNEL_HIB_FATAL_ERR_INTVECCTL = 0x46048,
++ APEX_BAR2_REG_KERNEL_HIB_DMA_PAUSE = 0x46050,
++ APEX_BAR2_REG_KERNEL_HIB_DMA_PAUSE_MASK = 0x46058,
++ APEX_BAR2_REG_KERNEL_HIB_STATUS_BLOCK_DELAY = 0x46060,
++ APEX_BAR2_REG_KERNEL_HIB_MSIX_PENDING_BIT_ARRAY0 = 0x46068,
++ APEX_BAR2_REG_KERNEL_HIB_MSIX_PENDING_BIT_ARRAY1 = 0x46070,
++ APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE_INIT = 0x46078,
++ APEX_BAR2_REG_KERNEL_HIB_MSIX_TABLE_INIT = 0x46080,
++ APEX_BAR2_REG_KERNEL_WIRE_INT_PENDING_BIT_ARRAY = 0x48778,
++ APEX_BAR2_REG_KERNEL_WIRE_INT_MASK_ARRAY = 0x48780,
++ APEX_BAR2_REG_USER_HIB_DMA_PAUSE = 0x486D8,
++ APEX_BAR2_REG_USER_HIB_DMA_PAUSED = 0x486E0,
++ APEX_BAR2_REG_IDLEGENERATOR_IDLEGEN_IDLEREGISTER = 0x4A000,
++ APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE = 0x50000,
++ APEX_BAR2_REG_OMC0_D0 = 0x01a0d0,
++ APEX_BAR2_REG_OMC0_D4 = 0x01a0d4,
++ APEX_BAR2_REG_OMC0_D8 = 0x01a0d8,
++ APEX_BAR2_REG_OMC0_DC = 0x01a0dc,
++ APEX_BAR2_REG_EFUSE_DC = 0x01a2dc,
++ APEX_BAR2_REG_EFUSE_E0 = 0x01a2e0,
++ APEX_BAR2_REG_EFUSE_E4 = 0x01a2e4,
++ APEX_BAR2_REG_EFUSE_E8 = 0x01a2e8,
++
++ /* Error registers - Used mostly for debug */
++ APEX_BAR2_REG_USER_HIB_ERROR_STATUS = 0x86f0,
++ APEX_BAR2_REG_SCALAR_CORE_ERROR_STATUS = 0x41a0,
++};
++
++/* Addresses for packed registers. */
++#define APEX_BAR2_REG_AXI_QUIESCE (APEX_BAR2_REG_SCU_BASE + 0x2C)
++#define APEX_BAR2_REG_GCB_CLOCK_GATE (APEX_BAR2_REG_SCU_BASE + 0x14)
++#define APEX_BAR2_REG_SCU_0 (APEX_BAR2_REG_SCU_BASE + 0xc)
++#define APEX_BAR2_REG_SCU_1 (APEX_BAR2_REG_SCU_BASE + 0x10)
++#define APEX_BAR2_REG_SCU_2 (APEX_BAR2_REG_SCU_BASE + 0x14)
++#define APEX_BAR2_REG_SCU_3 (APEX_BAR2_REG_SCU_BASE + 0x18)
++#define APEX_BAR2_REG_SCU_4 (APEX_BAR2_REG_SCU_BASE + 0x1c)
++#define APEX_BAR2_REG_SCU_5 (APEX_BAR2_REG_SCU_BASE + 0x20)
++
++#define SCU3_RG_PWR_STATE_OVR_BIT_OFFSET 26
++#define SCU3_RG_PWR_STATE_OVR_MASK_WIDTH 2
++#define SCU3_CUR_RST_GCB_BIT_MASK 0x10
++#define SCU2_RG_RST_GCB_BIT_MASK 0xc
++
++/* Configuration for page table. */
++static struct gasket_page_table_config apex_page_table_configs[NUM_NODES] = {
++ {
++ .id = 0,
++ .mode = GASKET_PAGE_TABLE_MODE_NORMAL,
++ .total_entries = APEX_PAGE_TABLE_TOTAL_ENTRIES,
++ .base_reg = APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE,
++ .extended_reg = APEX_BAR2_REG_KERNEL_HIB_EXTENDED_TABLE,
++ .extended_bit = APEX_EXTENDED_SHIFT,
++ },
++};
++
++/* The regions in the BAR2 space that can be mapped into user space. */
++static const struct gasket_mappable_region mappable_regions[NUM_REGIONS] = {
++ { 0x40000, 0x1000 },
++ { 0x44000, 0x1000 },
++ { 0x48000, 0x1000 },
++};
++
++/* Gasket device interrupts enums must be dense (i.e., no empty slots). */
++enum apex_interrupt {
++ APEX_INTERRUPT_INSTR_QUEUE = 0,
++ APEX_INTERRUPT_INPUT_ACTV_QUEUE = 1,
++ APEX_INTERRUPT_PARAM_QUEUE = 2,
++ APEX_INTERRUPT_OUTPUT_ACTV_QUEUE = 3,
++ APEX_INTERRUPT_SC_HOST_0 = 4,
++ APEX_INTERRUPT_SC_HOST_1 = 5,
++ APEX_INTERRUPT_SC_HOST_2 = 6,
++ APEX_INTERRUPT_SC_HOST_3 = 7,
++ APEX_INTERRUPT_TOP_LEVEL_0 = 8,
++ APEX_INTERRUPT_TOP_LEVEL_1 = 9,
++ APEX_INTERRUPT_TOP_LEVEL_2 = 10,
++ APEX_INTERRUPT_TOP_LEVEL_3 = 11,
++ APEX_INTERRUPT_FATAL_ERR = 12,
++ APEX_INTERRUPT_COUNT = 13,
++};
++
++/* Interrupt descriptors for Apex */
++static struct gasket_interrupt_desc apex_interrupts[] = {
++ {
++ APEX_INTERRUPT_INSTR_QUEUE,
++ APEX_BAR2_REG_KERNEL_HIB_INSTR_QUEUE_INTVECCTL,
++ UNPACKED,
++ },
++ {
++ APEX_INTERRUPT_INPUT_ACTV_QUEUE,
++ APEX_BAR2_REG_KERNEL_HIB_INPUT_ACTV_QUEUE_INTVECCTL,
++ UNPACKED
++ },
++ {
++ APEX_INTERRUPT_PARAM_QUEUE,
++ APEX_BAR2_REG_KERNEL_HIB_PARAM_QUEUE_INTVECCTL,
++ UNPACKED
++ },
++ {
++ APEX_INTERRUPT_OUTPUT_ACTV_QUEUE,
++ APEX_BAR2_REG_KERNEL_HIB_OUTPUT_ACTV_QUEUE_INTVECCTL,
++ UNPACKED
++ },
++ {
++ APEX_INTERRUPT_SC_HOST_0,
++ APEX_BAR2_REG_KERNEL_HIB_SC_HOST_INTVECCTL,
++ PACK_0
++ },
++ {
++ APEX_INTERRUPT_SC_HOST_1,
++ APEX_BAR2_REG_KERNEL_HIB_SC_HOST_INTVECCTL,
++ PACK_1
++ },
++ {
++ APEX_INTERRUPT_SC_HOST_2,
++ APEX_BAR2_REG_KERNEL_HIB_SC_HOST_INTVECCTL,
++ PACK_2
++ },
++ {
++ APEX_INTERRUPT_SC_HOST_3,
++ APEX_BAR2_REG_KERNEL_HIB_SC_HOST_INTVECCTL,
++ PACK_3
++ },
++ {
++ APEX_INTERRUPT_TOP_LEVEL_0,
++ APEX_BAR2_REG_KERNEL_HIB_TOP_LEVEL_INTVECCTL,
++ PACK_0
++ },
++ {
++ APEX_INTERRUPT_TOP_LEVEL_1,
++ APEX_BAR2_REG_KERNEL_HIB_TOP_LEVEL_INTVECCTL,
++ PACK_1
++ },
++ {
++ APEX_INTERRUPT_TOP_LEVEL_2,
++ APEX_BAR2_REG_KERNEL_HIB_TOP_LEVEL_INTVECCTL,
++ PACK_2
++ },
++ {
++ APEX_INTERRUPT_TOP_LEVEL_3,
++ APEX_BAR2_REG_KERNEL_HIB_TOP_LEVEL_INTVECCTL,
++ PACK_3
++ },
++ {
++ APEX_INTERRUPT_FATAL_ERR,
++ APEX_BAR2_REG_KERNEL_HIB_FATAL_ERR_INTVECCTL,
++ UNPACKED
++ },
++};
++
++/* Allows device to enter power save upon driver close(). */
++static int allow_power_save = 1;
++
++/* Allows SW based clock gating. */
++static int allow_sw_clock_gating;
++
++/* Allows HW based clock gating. */
++/* Note: this is not mutual exclusive with SW clock gating. */
++static int allow_hw_clock_gating = 1;
++
++/* Act as if only GCB is instantiated. */
++static int bypass_top_level;
++
++module_param(allow_power_save, int, 0644);
++module_param(allow_sw_clock_gating, int, 0644);
++module_param(allow_hw_clock_gating, int, 0644);
++module_param(bypass_top_level, int, 0644);
++
++/* Temperature points in milli C at which DFS is toggled */
++#define DEFAULT_TRIP_POINT0_TEMP 85000
++#define DEFAULT_TRIP_POINT1_TEMP 90000
++#define DEFAULT_TRIP_POINT2_TEMP 95000
++
++static int trip_point0_temp = DEFAULT_TRIP_POINT0_TEMP;
++static int trip_point1_temp = DEFAULT_TRIP_POINT1_TEMP;
++static int trip_point2_temp = DEFAULT_TRIP_POINT2_TEMP;
++
++module_param(trip_point0_temp, int, 0644);
++module_param(trip_point1_temp, int, 0644);
++module_param(trip_point2_temp, int, 0644);
++
++/* Hardware monitored temperature trip points in milli C
++ Apex chip drives INTR line when reaching hw_temp_warn1 temperature,
++ and SD_ALARM line when reaching hw_temp_warn2 if corresponding
++ hw_temp_warn*_en is set to true.
++ */
++static int hw_temp_warn1 = 100000;
++static int hw_temp_warn2 = 100000;
++static bool hw_temp_warn1_en = false;
++static bool hw_temp_warn2_en = true;
++
++module_param(hw_temp_warn1, int, 0644);
++module_param(hw_temp_warn2, int, 0644);
++module_param(hw_temp_warn1_en, bool, 0644);
++module_param(hw_temp_warn2_en, bool, 0644);
++
++/* Temperature poll interval in ms */
++static int temp_poll_interval = DEFAULT_APEX_TEMP_POLL_INTERVAL;
++module_param(temp_poll_interval, int, 0644);
++
++/* Check the device status registers and return device status ALIVE or DEAD. */
++static int apex_get_status(struct gasket_dev *gasket_dev)
++{
++ /* TODO: Check device status. */
++ return GASKET_STATUS_ALIVE;
++}
++
++/* Enter GCB reset state. */
++static int apex_enter_reset(struct gasket_dev *gasket_dev)
++{
++ if (bypass_top_level)
++ return 0;
++
++ /*
++ * Software reset:
++ * Enable sleep mode
++ * - Software force GCB idle
++ * - Enable GCB idle
++ */
++ gasket_read_modify_write_64(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_IDLEGENERATOR_IDLEGEN_IDLEREGISTER,
++ 0x0, 1, 32);
++
++ /* - Initiate DMA pause */
++ gasket_dev_write_64(gasket_dev, 1, APEX_BAR_INDEX,
++ APEX_BAR2_REG_USER_HIB_DMA_PAUSE);
++
++ /* - Wait for DMA pause complete. */
++ if (gasket_wait_with_reschedule(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_USER_HIB_DMA_PAUSED, 1, 1,
++ APEX_RESET_DELAY, APEX_RESET_RETRY)) {
++ dev_err(gasket_dev->dev,
++ "DMAs did not quiesce within timeout (%d ms)\n",
++ APEX_RESET_RETRY * APEX_RESET_DELAY);
++ return -ETIMEDOUT;
++ }
++
++ /* - Enable GCB reset (0x1 to rg_rst_gcb) */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_2, 0x1, 2, 2);
++
++ /* - Enable GCB clock Gate (0x1 to rg_gated_gcb) */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_2, 0x1, 2, 18);
++
++ /* - Enable GCB memory shut down (0x3 to rg_force_ram_sd) */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3, 0x3, 2, 14);
++
++ /* - Wait for RAM shutdown. */
++ if (gasket_wait_with_reschedule(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3, 1 << 6, 1 << 6,
++ APEX_RESET_DELAY, APEX_RESET_RETRY)) {
++ dev_err(gasket_dev->dev,
++ "RAM did not shut down within timeout (%d ms)\n",
++ APEX_RESET_RETRY * APEX_RESET_DELAY);
++ return -ETIMEDOUT;
++ }
++
++ return 0;
++}
++
++/* Quit GCB reset state. */
++static int apex_quit_reset(struct gasket_dev *gasket_dev)
++{
++ u32 val0, val1;
++
++ if (bypass_top_level)
++ return 0;
++
++ /*
++ * Disable sleep mode:
++ * - Disable GCB memory shut down:
++ * - b00: Not forced (HW controlled)
++ * - b1x: Force disable
++ */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3, 0x0, 2, 14);
++
++ /*
++ * - Disable software clock gate:
++ * - b00: Not forced (HW controlled)
++ * - b1x: Force disable
++ */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_2, 0x0, 2, 18);
++
++ /*
++ * - Disable GCB reset (rg_rst_gcb):
++ * - b00: Not forced (HW controlled)
++ * - b1x: Force disable = Force not Reset
++ */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_2, 0x2, 2, 2);
++
++ /* - Wait for RAM enable. */
++ if (gasket_wait_with_reschedule(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3, 1 << 6, 0,
++ APEX_RESET_DELAY, APEX_RESET_RETRY)) {
++ dev_err(gasket_dev->dev,
++ "RAM did not enable within timeout (%d ms)\n",
++ APEX_RESET_RETRY * APEX_RESET_DELAY);
++ return -ETIMEDOUT;
++ }
++
++ /* - Wait for Reset complete. */
++ if (gasket_wait_with_reschedule(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3,
++ SCU3_CUR_RST_GCB_BIT_MASK, 0,
++ APEX_RESET_DELAY, APEX_RESET_RETRY)) {
++ dev_err(gasket_dev->dev,
++ "GCB did not leave reset within timeout (%d ms)\n",
++ APEX_RESET_RETRY * APEX_RESET_DELAY);
++ return -ETIMEDOUT;
++ }
++
++ if (!allow_hw_clock_gating) {
++ val0 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++ /* Inactive and Sleep mode are disabled. */
++ gasket_read_modify_write_32(gasket_dev,
++ APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3, 0x3,
++ SCU3_RG_PWR_STATE_OVR_MASK_WIDTH,
++ SCU3_RG_PWR_STATE_OVR_BIT_OFFSET);
++ val1 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++ dev_dbg(gasket_dev->dev,
++ "Disallow HW clock gating 0x%x -> 0x%x\n", val0, val1);
++ } else {
++ val0 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++ /* Inactive mode enabled - Sleep mode disabled. */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3, 2,
++ SCU3_RG_PWR_STATE_OVR_MASK_WIDTH,
++ SCU3_RG_PWR_STATE_OVR_BIT_OFFSET);
++ val1 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++ dev_dbg(gasket_dev->dev, "Allow HW clock gating 0x%x -> 0x%x\n",
++ val0, val1);
++ }
++
++ return 0;
++}
++
++/* Reset the Apex hardware. Called on final close via device_close_cb. */
++static int apex_device_cleanup(struct gasket_dev *gasket_dev)
++{
++ u64 scalar_error;
++ u64 hib_error;
++ int ret = 0;
++
++ hib_error = gasket_dev_read_64(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_USER_HIB_ERROR_STATUS);
++ scalar_error = gasket_dev_read_64(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCALAR_CORE_ERROR_STATUS);
++
++ dev_dbg(gasket_dev->dev,
++ "%s 0x%p hib_error 0x%llx scalar_error 0x%llx\n",
++ __func__, gasket_dev, hib_error, scalar_error);
++
++ if (allow_power_save)
++ ret = apex_enter_reset(gasket_dev);
++
++ return ret;
++}
++
++/* Determine if GCB is in reset state. */
++static bool is_gcb_in_reset(struct gasket_dev *gasket_dev)
++{
++ u32 val = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++
++ /* Masks rg_rst_gcb bit of SCU_CTRL_2 */
++ return (val & SCU3_CUR_RST_GCB_BIT_MASK);
++}
++
++/* Reset the hardware, then quit reset. Called on device open. */
++static int apex_reset(struct gasket_dev *gasket_dev)
++{
++ int ret;
++
++ if (bypass_top_level)
++ return 0;
++
++ if (!is_gcb_in_reset(gasket_dev)) {
++ /* We are not in reset - toggle the reset bit so as to force
++ * re-init of custom block
++ */
++ dev_dbg(gasket_dev->dev, "%s: toggle reset\n", __func__);
++
++ ret = apex_enter_reset(gasket_dev);
++ if (ret)
++ return ret;
++ }
++ ret = apex_quit_reset(gasket_dev);
++
++ return ret;
++}
++
++/*
++ * Check permissions for Apex ioctls.
++ * Returns true if the current user may execute this ioctl, and false otherwise.
++ */
++static bool apex_ioctl_check_permissions(struct file *filp, uint cmd)
++{
++ return !!(filp->f_mode & FMODE_WRITE);
++}
++
++/* Gates or un-gates Apex clock. */
++static long apex_clock_gating(struct gasket_dev *gasket_dev,
++ struct apex_gate_clock_ioctl __user *argp)
++{
++ struct apex_gate_clock_ioctl ibuf;
++
++ if (bypass_top_level || !allow_sw_clock_gating)
++ return 0;
++
++ if (copy_from_user(&ibuf, argp, sizeof(ibuf)))
++ return -EFAULT;
++
++ dev_dbg(gasket_dev->dev, "%s %llu\n", __func__, ibuf.enable);
++
++ if (ibuf.enable) {
++ /* Quiesce AXI, gate GCB clock. */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_AXI_QUIESCE, 0x1, 1,
++ 16);
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_GCB_CLOCK_GATE, 0x1,
++ 2, 18);
++ } else {
++ /* Un-gate GCB clock, un-quiesce AXI. */
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_GCB_CLOCK_GATE, 0x0,
++ 2, 18);
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_AXI_QUIESCE, 0x0, 1,
++ 16);
++ }
++ return 0;
++}
++
++/* apex_set_performance_expectation: Adjust clock rates for Apex. */
++static long apex_set_performance_expectation(
++ struct gasket_dev *gasket_dev,
++ struct apex_performance_expectation_ioctl __user *argp)
++{
++ struct apex_performance_expectation_ioctl ibuf;
++ uint32_t rg_gcb_clk_div = 0;
++ uint32_t rg_axi_clk_fixed = 0;
++ const int AXI_CLK_FIXED_SHIFT = 2;
++ const int MCU_CLK_FIXED_SHIFT = 3;
++
++ // 8051 clock is fixed for PCIe, as it's not used at all.
++ const uint32_t rg_8051_clk_fixed = 1;
++
++ if (bypass_top_level)
++ return 0;
++
++ if (copy_from_user(&ibuf, argp, sizeof(ibuf)))
++ return -EFAULT;
++
++ switch (ibuf.performance) {
++ case APEX_PERFORMANCE_LOW:
++ rg_gcb_clk_div = 3;
++ rg_axi_clk_fixed = 0;
++ break;
++
++ case APEX_PERFORMANCE_MED:
++ rg_gcb_clk_div = 2;
++ rg_axi_clk_fixed = 0;
++ break;
++
++ case APEX_PERFORMANCE_HIGH:
++ rg_gcb_clk_div = 1;
++ rg_axi_clk_fixed = 0;
++ break;
++
++ case APEX_PERFORMANCE_MAX:
++ rg_gcb_clk_div = 0;
++ rg_axi_clk_fixed = 0;
++ break;
++
++ default:
++ return -EINVAL;
++ }
++
++ /*
++ * Set clock rates for GCB, AXI, and 8051:
++ */
++ gasket_read_modify_write_32(
++ gasket_dev, APEX_BAR_INDEX, APEX_BAR2_REG_SCU_3,
++ (rg_gcb_clk_div | (rg_axi_clk_fixed << AXI_CLK_FIXED_SHIFT) | (rg_8051_clk_fixed << MCU_CLK_FIXED_SHIFT)),
++ /*mask_width=*/4, /*mask_shift=*/28);
++
++ return 0;
++}
++
++/* Apex-specific ioctl handler. */
++static long apex_ioctl(struct file *filp, uint cmd, void __user *argp)
++{
++ struct gasket_dev *gasket_dev = filp->private_data;
++
++ if (!apex_ioctl_check_permissions(filp, cmd))
++ return -EPERM;
++
++ switch (cmd) {
++ case APEX_IOCTL_GATE_CLOCK:
++ return apex_clock_gating(gasket_dev, argp);
++ case APEX_IOCTL_PERFORMANCE_EXPECTATION:
++ return apex_set_performance_expectation(gasket_dev, argp);
++ default:
++ return -ENOTTY; /* unknown command */
++ }
++}
++
++/* Linear fit optimized for 25C-100C */
++static int adc_to_millic(int adc)
++{
++ return (662 - adc) * 250 + 550;
++}
++
++static int millic_to_adc(int millic)
++{
++ return (550 - millic) / 250 + 662;
++}
++
++/* Display driver sysfs entries. */
++static ssize_t sysfs_show(struct device *device, struct device_attribute *attr,
++ char *buf)
++{
++ int ret;
++ unsigned value, value2, value3, value4;
++ struct gasket_dev *gasket_dev;
++ struct apex_dev *apex_dev;
++ struct gasket_sysfs_attribute *gasket_attr;
++ enum sysfs_attribute_type type;
++
++ gasket_dev = gasket_sysfs_get_device_data(device);
++ if (!gasket_dev) {
++ dev_err(device, "No Apex device sysfs mapping found\n");
++ return -ENODEV;
++ }
++
++ if (!gasket_dev->pci_dev ||
++ !(apex_dev = pci_get_drvdata(gasket_dev->pci_dev))) {
++ dev_err(device, "Can't find apex_dev data\n");
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return -ENODEV;
++ }
++
++ gasket_attr = gasket_sysfs_get_attr(device, attr);
++ if (!gasket_attr) {
++ dev_err(device, "No Apex device sysfs attr data found\n");
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return -ENODEV;
++ }
++
++ type = (enum sysfs_attribute_type)gasket_attr->data.attr_type;
++ switch (type) {
++ case ATTR_KERNEL_HIB_PAGE_TABLE_SIZE:
++ ret = scnprintf(buf, PAGE_SIZE, "%u\n",
++ gasket_page_table_num_entries(
++ gasket_dev->page_table[0]));
++ break;
++ case ATTR_KERNEL_HIB_SIMPLE_PAGE_TABLE_SIZE:
++ ret = scnprintf(buf, PAGE_SIZE, "%u\n",
++ gasket_page_table_num_entries(
++ gasket_dev->page_table[0]));
++ break;
++ case ATTR_KERNEL_HIB_NUM_ACTIVE_PAGES:
++ ret = scnprintf(buf, PAGE_SIZE, "%u\n",
++ gasket_page_table_num_active_pages(
++ gasket_dev->page_table[0]));
++ break;
++ case ATTR_TEMP:
++ value = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_DC);
++ value = (value >> 16) & ((1 << 10) - 1);
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n", adc_to_millic(value));
++ break;
++ case ATTR_TEMP_WARN1:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ adc_to_millic(apex_dev->hw_temp_warn1_adc));
++ break;
++ case ATTR_TEMP_WARN2:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ adc_to_millic(apex_dev->hw_temp_warn2_adc));
++ break;
++ case ATTR_TEMP_WARN1_EN:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ apex_dev->hw_temp_warn1_en);
++ break;
++ case ATTR_TEMP_WARN2_EN:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ apex_dev->hw_temp_warn2_en);
++ break;
++ case ATTR_TEMP_TRIP0:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ adc_to_millic(apex_dev->adc_trip_points[0]));
++ break;
++ case ATTR_TEMP_TRIP1:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ adc_to_millic(apex_dev->adc_trip_points[1]));
++ break;
++ case ATTR_TEMP_TRIP2:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ adc_to_millic(apex_dev->adc_trip_points[2]));
++ break;
++ case ATTR_TEMP_POLL_INTERVAL:
++ ret = scnprintf(buf, PAGE_SIZE, "%i\n",
++ atomic_read(&apex_dev->temp_poll_interval));
++ break;
++ case ATTR_UNIQUE_ID:
++ value = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_EFUSE_DC);
++ value2 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_EFUSE_E0);
++ value3 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_EFUSE_E4);
++ value4 = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_EFUSE_E8);
++ ret = snprintf(buf, PAGE_SIZE, "%.8x%.8x%.8x%.8x\n", value4,
++ value3, value2, value);
++ break;
++
++ default:
++ dev_dbg(gasket_dev->dev, "Unknown attribute: %s\n",
++ attr->attr.name);
++ ret = 0;
++ break;
++ }
++
++ gasket_sysfs_put_attr(device, gasket_attr);
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return ret;
++}
++
++/* Set driver sysfs entries. */
++static ssize_t sysfs_store(struct device *device, struct device_attribute *attr,
++ const char *buf, size_t count)
++{
++ int ret = count, value;
++ struct gasket_dev *gasket_dev;
++ struct apex_dev *apex_dev;
++ struct gasket_sysfs_attribute *gasket_attr;
++ enum sysfs_attribute_type type;
++
++ if (kstrtoint(buf, 10, &value))
++ return -EINVAL;
++
++ gasket_dev = gasket_sysfs_get_device_data(device);
++ if (!gasket_dev) {
++ dev_err(device, "No Apex device sysfs mapping found\n");
++ return -ENODEV;
++ }
++
++ if (!gasket_dev->pci_dev ||
++ !(apex_dev = pci_get_drvdata(gasket_dev->pci_dev))) {
++ dev_err(device, "Can't find apex_dev data\n");
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return -ENODEV;
++ }
++
++ gasket_attr = gasket_sysfs_get_attr(device, attr);
++ if (!gasket_attr) {
++ dev_err(device, "No Apex device sysfs attr data found\n");
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return -ENODEV;
++ }
++
++ type = (enum sysfs_attribute_type)gasket_attr->data.attr_type;
++ switch (type) {
++ case ATTR_TEMP_WARN1:
++ value = millic_to_adc(value);
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D4, value, 10,
++ 16);
++ apex_dev->hw_temp_warn1_adc = value;
++ break;
++ case ATTR_TEMP_WARN2:
++ value = millic_to_adc(value);
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D8, value, 10,
++ 16);
++ apex_dev->hw_temp_warn2_adc = value;
++ break;
++ case ATTR_TEMP_WARN1_EN:
++ value = value > 0 ? 1 : 0;
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D4, value, 1,
++ 31);
++ apex_dev->hw_temp_warn1_en = !!value;
++ break;
++ case ATTR_TEMP_WARN2_EN:
++ value = value > 0 ? 1 : 0;
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D8, value, 1,
++ 31);
++ apex_dev->hw_temp_warn2_en = !!value;
++ break;
++ case ATTR_TEMP_TRIP0:
++ value = millic_to_adc(value);
++ /* Note: that adc values should be in descending order */
++ if (value >= apex_dev->adc_trip_points[1]) {
++ apex_dev->adc_trip_points[0] = value;
++ } else ret = -EINVAL;
++ break;
++ case ATTR_TEMP_TRIP1:
++ value = millic_to_adc(value);
++ if (value <= apex_dev->adc_trip_points[0] &&
++ value >= apex_dev->adc_trip_points[2]) {
++ apex_dev->adc_trip_points[1] = value;
++ } else ret = -EINVAL;
++ break;
++ case ATTR_TEMP_TRIP2:
++ value = millic_to_adc(value);
++ if (value <= apex_dev->adc_trip_points[1]) {
++ apex_dev->adc_trip_points[2] = value;
++ } else ret = -EINVAL;
++ break;
++ case ATTR_TEMP_POLL_INTERVAL:
++ cancel_delayed_work_sync(&apex_dev->check_temperature_work);
++ atomic_set(&apex_dev->temp_poll_interval, value);
++ if (value > 0)
++ schedule_delayed_work(&apex_dev->check_temperature_work,
++ msecs_to_jiffies(value));
++
++ break;
++ default:
++ dev_dbg(gasket_dev->dev, "Unknown attribute: %s\n",
++ attr->attr.name);
++ ret = 0;
++ break;
++ }
++
++ gasket_sysfs_put_attr(device, gasket_attr);
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return ret;
++}
++
++static struct gasket_sysfs_attribute apex_sysfs_attrs[] = {
++ GASKET_SYSFS_RO(node_0_page_table_entries, sysfs_show,
++ ATTR_KERNEL_HIB_PAGE_TABLE_SIZE),
++ GASKET_SYSFS_RO(node_0_simple_page_table_entries, sysfs_show,
++ ATTR_KERNEL_HIB_SIMPLE_PAGE_TABLE_SIZE),
++ GASKET_SYSFS_RO(node_0_num_mapped_pages, sysfs_show,
++ ATTR_KERNEL_HIB_NUM_ACTIVE_PAGES),
++ GASKET_SYSFS_RO(temp, sysfs_show, ATTR_TEMP),
++ GASKET_SYSFS_RW(hw_temp_warn1, sysfs_show, sysfs_store,
++ ATTR_TEMP_WARN1),
++ GASKET_SYSFS_RW(hw_temp_warn1_en, sysfs_show, sysfs_store,
++ ATTR_TEMP_WARN1_EN),
++ GASKET_SYSFS_RW(hw_temp_warn2, sysfs_show, sysfs_store,
++ ATTR_TEMP_WARN2),
++ GASKET_SYSFS_RW(hw_temp_warn2_en, sysfs_show, sysfs_store,
++ ATTR_TEMP_WARN2_EN),
++ GASKET_SYSFS_RW(trip_point0_temp, sysfs_show, sysfs_store,
++ ATTR_TEMP_TRIP0),
++ GASKET_SYSFS_RW(trip_point1_temp, sysfs_show, sysfs_store,
++ ATTR_TEMP_TRIP1),
++ GASKET_SYSFS_RW(trip_point2_temp, sysfs_show, sysfs_store,
++ ATTR_TEMP_TRIP2),
++ GASKET_SYSFS_RW(temp_poll_interval, sysfs_show, sysfs_store,
++ ATTR_TEMP_POLL_INTERVAL),
++ GASKET_SYSFS_RO(unique_id, sysfs_show, ATTR_UNIQUE_ID),
++ GASKET_END_OF_ATTR_ARRAY
++};
++
++/* Stores kernel module parameters to device specific data buffer */
++static void apply_module_params(struct apex_dev *apex_dev) {
++ kernel_param_lock(THIS_MODULE);
++
++ /* use defaults if trip point temperatures are not in ascending order */
++ if (trip_point0_temp > trip_point1_temp ||
++ trip_point1_temp > trip_point2_temp) {
++ dev_warn(apex_dev->gasket_dev_ptr->dev,
++ "Invalid module parameters for temperature trip points"
++ ", using defaults\n");
++ trip_point0_temp = DEFAULT_TRIP_POINT0_TEMP;
++ trip_point1_temp = DEFAULT_TRIP_POINT1_TEMP;
++ trip_point2_temp = DEFAULT_TRIP_POINT2_TEMP;
++ }
++
++ apex_dev->adc_trip_points[0] = millic_to_adc(trip_point0_temp);
++ apex_dev->adc_trip_points[1] = millic_to_adc(trip_point1_temp);
++ apex_dev->adc_trip_points[2] = millic_to_adc(trip_point2_temp);
++ atomic_set(&apex_dev->temp_poll_interval, temp_poll_interval);
++
++ apex_dev->hw_temp_warn1_adc = millic_to_adc(hw_temp_warn1);
++ apex_dev->hw_temp_warn2_adc = millic_to_adc(hw_temp_warn2);
++ apex_dev->hw_temp_warn1_en = hw_temp_warn1_en;
++ apex_dev->hw_temp_warn2_en = hw_temp_warn2_en;
++
++ kernel_param_unlock(THIS_MODULE);
++}
++
++/* Applies hw temp warning settings to device */
++static void program_hw_temp_warnings(struct apex_dev *apex_dev) {
++ gasket_read_modify_write_32(apex_dev->gasket_dev_ptr, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D4,
++ apex_dev->hw_temp_warn1_adc, 10, 16);
++ gasket_read_modify_write_32(apex_dev->gasket_dev_ptr, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D8,
++ apex_dev->hw_temp_warn2_adc, 10, 16);
++ if (apex_dev->hw_temp_warn1_en)
++ gasket_read_modify_write_32(apex_dev->gasket_dev_ptr,
++ APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D4, 1, 1, 31);
++
++ if (apex_dev->hw_temp_warn2_en)
++ gasket_read_modify_write_32(apex_dev->gasket_dev_ptr,
++ APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D8, 1, 1, 31);
++}
++
++static void enable_thermal_sensing(struct gasket_dev *gasket_dev) {
++ // Enable thermal sensor clocks
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D0, 0x1, 1, 7);
++
++ // Enable thermal sensor (ENAD ENVR ENBG)
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_D8, 0x7, 3, 0);
++
++ // Enable OMC thermal sensor controller
++ // This bit should be asserted 100 us after ENAD ENVR ENBG
++ schedule_timeout(usecs_to_jiffies(100));
++ gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_DC, 0x1, 1, 0);
++}
++
++static void check_temperature_work_handler(struct work_struct *work) {
++ int i, temp_poll_interval;
++ u32 adc_temp, clk_div, tmp;
++ const u32 mask = ((1 << 2) - 1) << 28;
++ struct apex_dev *apex_dev =
++ container_of(work, struct apex_dev,
++ check_temperature_work.work);
++ struct gasket_dev *gasket_dev = apex_dev->gasket_dev_ptr;
++
++ mutex_lock(&gasket_dev->mutex);
++
++ /* Read current temperature */
++ adc_temp = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_OMC0_DC);
++ adc_temp = (adc_temp >> 16) & ((1 << 10) - 1);
++
++ /* Find closest trip point
++ Note: that adc values are in descending order */
++ for (i = ARRAY_SIZE(apex_dev->adc_trip_points) - 1; i >= 0; --i) {
++ if (adc_temp <= apex_dev->adc_trip_points[i])
++ break;
++ }
++ /* Compute divider value and shift into appropriate bit location */
++ clk_div = (i + 1) << 28;
++
++ /* Modify gcb clk divider if it's different from current one */
++ tmp = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++ if (clk_div != (tmp & mask)) {
++ tmp = (tmp & ~mask) | clk_div;
++ gasket_dev_write_32(gasket_dev, tmp, APEX_BAR_INDEX,
++ APEX_BAR2_REG_SCU_3);
++ dev_warn(gasket_dev->dev,
++ "Apex performance %sthrottled due to temperature\n",
++ i == -1 ? "not " : "");
++ }
++
++ mutex_unlock(&gasket_dev->mutex);
++
++ temp_poll_interval = atomic_read(&apex_dev->temp_poll_interval);
++ if (temp_poll_interval > 0)
++ schedule_delayed_work(&apex_dev->check_temperature_work,
++ msecs_to_jiffies(temp_poll_interval));
++}
++
++/* On device open, perform a core reinit reset. */
++static int apex_device_open_cb(struct gasket_dev *gasket_dev)
++{
++ return gasket_reset_nolock(gasket_dev);
++}
++
++static const struct pci_device_id apex_pci_ids[] = {
++ { PCI_DEVICE(APEX_PCI_VENDOR_ID, APEX_PCI_DEVICE_ID) }, { 0 }
++};
++
++static void apex_pci_fixup_class(struct pci_dev *pdev)
++{
++ pdev->class = (PCI_CLASS_SYSTEM_OTHER << 8) | pdev->class;
++}
++DECLARE_PCI_FIXUP_CLASS_HEADER(APEX_PCI_VENDOR_ID, APEX_PCI_DEVICE_ID,
++ PCI_ANY_ID, 8, apex_pci_fixup_class);
++
++static int apex_pci_probe(struct pci_dev *pci_dev,
++ const struct pci_device_id *id)
++{
++ int ret, temp_poll_interval;
++ ulong page_table_ready, msix_table_ready;
++ int retries = 0;
++ struct gasket_dev *gasket_dev;
++ struct apex_dev *apex_dev;
++
++ ret = pci_enable_device(pci_dev);
++#ifdef MODULE
++ if (ret) {
++ apex_pci_fixup_class(pci_dev);
++ pci_bus_assign_resources(pci_dev->bus);
++ ret = pci_enable_device(pci_dev);
++ }
++#endif
++ if (ret) {
++ dev_err(&pci_dev->dev, "error enabling PCI device\n");
++ return ret;
++ }
++
++ pci_set_master(pci_dev);
++
++ ret = gasket_pci_add_device(pci_dev, &gasket_dev);
++ if (ret) {
++ dev_err(&pci_dev->dev, "error adding gasket device\n");
++ pci_disable_device(pci_dev);
++ return ret;
++ }
++
++ apex_dev = kzalloc(sizeof(*apex_dev), GFP_KERNEL);
++ if (!apex_dev) {
++ dev_err(&pci_dev->dev, "no memory for device\n");
++ ret = -ENOMEM;
++ goto remove_device;
++ }
++
++ INIT_DELAYED_WORK(&apex_dev->check_temperature_work,
++ check_temperature_work_handler);
++ apex_dev->gasket_dev_ptr = gasket_dev;
++ apply_module_params(apex_dev);
++ program_hw_temp_warnings(apex_dev);
++ pci_set_drvdata(pci_dev, apex_dev);
++ apex_reset(gasket_dev);
++
++ while (retries < APEX_RESET_RETRY) {
++ page_table_ready =
++ gasket_dev_read_64(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE_INIT);
++ msix_table_ready =
++ gasket_dev_read_64(gasket_dev, APEX_BAR_INDEX,
++ APEX_BAR2_REG_KERNEL_HIB_MSIX_TABLE_INIT);
++ if (page_table_ready && msix_table_ready)
++ break;
++ schedule_timeout(msecs_to_jiffies(APEX_RESET_DELAY));
++ retries++;
++ }
++
++ if (retries == APEX_RESET_RETRY) {
++ if (!page_table_ready)
++ dev_err(gasket_dev->dev, "Page table init timed out\n");
++ if (!msix_table_ready)
++ dev_err(gasket_dev->dev, "MSI-X table init timed out\n");
++ ret = -ETIMEDOUT;
++ goto remove_device;
++ }
++
++ enable_thermal_sensing(gasket_dev);
++
++ ret = gasket_sysfs_create_entries(gasket_dev->dev_info.device,
++ apex_sysfs_attrs);
++ if (ret)
++ dev_err(&pci_dev->dev, "error creating device sysfs entries\n");
++
++ ret = gasket_enable_device(gasket_dev);
++ if (ret) {
++ dev_err(&pci_dev->dev, "error enabling gasket device\n");
++ goto remove_device;
++ }
++
++ /* Place device in low power mode until opened */
++ if (allow_power_save)
++ apex_enter_reset(gasket_dev);
++
++ /* Enable thermal polling */
++ temp_poll_interval = atomic_read(&apex_dev->temp_poll_interval);
++ if (temp_poll_interval > 0)
++ schedule_delayed_work(&apex_dev->check_temperature_work,
++ msecs_to_jiffies(temp_poll_interval));
++ return 0;
++
++remove_device:
++ gasket_pci_remove_device(pci_dev);
++ pci_disable_device(pci_dev);
++ kfree(apex_dev);
++ return ret;
++}
++
++static void apex_pci_remove(struct pci_dev *pci_dev)
++{
++ struct apex_dev *apex_dev = pci_get_drvdata(pci_dev);
++ struct gasket_dev *gasket_dev;
++
++ if (!apex_dev) {
++ dev_err(&pci_dev->dev, "NULL apex_dev\n");
++ goto remove_device;
++ }
++ gasket_dev = apex_dev->gasket_dev_ptr;
++
++ cancel_delayed_work_sync(&apex_dev->check_temperature_work);
++ kfree(apex_dev);
++
++ gasket_disable_device(gasket_dev);
++remove_device:
++ gasket_pci_remove_device(pci_dev);
++ pci_disable_device(pci_dev);
++}
++
++static int apex_pci_suspend(struct pci_dev *pci_dev, pm_message_t state) {
++ struct apex_dev *apex_dev = pci_get_drvdata(pci_dev);
++ struct gasket_dev *gasket_dev;
++
++ if (!apex_dev) {
++ dev_err_once(&pci_dev->dev, "NULL apex_dev\n");
++ return -ENODEV;
++ }
++
++ // Tear down MSI-x interrupts before suspending.
++ gasket_dev = apex_dev->gasket_dev_ptr;
++ gasket_interrupt_msix_cleanup(gasket_dev->interrupt_data);
++ return 0;
++}
++
++static int apex_pci_resume(struct pci_dev *pci_dev)
++{
++ struct apex_dev *apex_dev = pci_get_drvdata(pci_dev);
++ struct gasket_dev *gasket_dev;
++
++ if (!apex_dev) {
++ dev_err_once(&pci_dev->dev, "NULL apex_dev\n");
++ return -ENODEV;
++ }
++ gasket_dev = apex_dev->gasket_dev_ptr;
++
++ gasket_interrupt_reinit(gasket_dev);
++ apex_reset(gasket_dev);
++ program_hw_temp_warnings(apex_dev);
++ enable_thermal_sensing(gasket_dev);
++
++ /* Place device in low power mode until opened */
++ if (allow_power_save)
++ apex_enter_reset(gasket_dev);
++
++ return 0;
++}
++
++static struct gasket_driver_desc apex_desc = {
++ .name = "apex",
++ .driver_version = APEX_DRIVER_VERSION,
++ .major = 120,
++ .minor = 0,
++ .module = THIS_MODULE,
++ .pci_id_table = apex_pci_ids,
++
++ .num_page_tables = NUM_NODES,
++ .page_table_bar_index = APEX_BAR_INDEX,
++ .page_table_configs = apex_page_table_configs,
++ .page_table_extended_bit = APEX_EXTENDED_SHIFT,
++
++ .bar_descriptions = {
++ GASKET_UNUSED_BAR,
++ GASKET_UNUSED_BAR,
++ { APEX_BAR_BYTES, (VM_WRITE | VM_READ), APEX_BAR_OFFSET,
++ NUM_REGIONS, mappable_regions, PCI_BAR },
++ GASKET_UNUSED_BAR,
++ GASKET_UNUSED_BAR,
++ GASKET_UNUSED_BAR,
++ },
++ .coherent_buffer_description = {
++ APEX_CH_MEM_BYTES,
++ (VM_WRITE | VM_READ),
++ APEX_CM_OFFSET,
++ },
++ .interrupt_type = PCI_MSIX,
++ .interrupt_bar_index = APEX_BAR_INDEX,
++ .num_interrupts = APEX_INTERRUPT_COUNT,
++ .interrupts = apex_interrupts,
++ .interrupt_pack_width = 7,
++
++ .device_open_cb = apex_device_open_cb,
++ .device_close_cb = apex_device_cleanup,
++
++ .ioctl_handler_cb = apex_ioctl,
++ .device_status_cb = apex_get_status,
++ .hardware_revision_cb = NULL,
++ .device_reset_cb = apex_reset,
++};
++
++static struct pci_driver apex_pci_driver = {
++ .name = "apex",
++ .probe = apex_pci_probe,
++ .remove = apex_pci_remove,
++#ifdef CONFIG_PM_SLEEP
++ .suspend = apex_pci_suspend,
++ .resume = apex_pci_resume,
++#endif
++ .id_table = apex_pci_ids,
++};
++
++static int __init apex_init(void)
++{
++ int ret;
++
++ ret = gasket_register_device(&apex_desc);
++ if (ret)
++ return ret;
++ ret = pci_register_driver(&apex_pci_driver);
++ if (ret)
++ gasket_unregister_device(&apex_desc);
++ return ret;
++}
++
++static void apex_exit(void)
++{
++ pci_unregister_driver(&apex_pci_driver);
++ gasket_unregister_device(&apex_desc);
++}
++MODULE_DESCRIPTION("Google Apex driver");
++MODULE_VERSION(APEX_DRIVER_VERSION);
++MODULE_LICENSE("GPL v2");
++MODULE_AUTHOR("John Joseph <jnjoseph@google.com>");
++MODULE_DEVICE_TABLE(pci, apex_pci_ids);
++module_init(apex_init);
++module_exit(apex_exit);
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/apex.h b/drivers/staging/gasket-driver/apex.h
+--- a/drivers/staging/gasket-driver/apex.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/apex.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,45 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/*
++ * Apex kernel-userspace interface definitions.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++#ifndef __APEX_H__
++#define __APEX_H__
++
++#include <linux/ioctl.h>
++
++/* Clock Gating ioctl. */
++struct apex_gate_clock_ioctl {
++ /* Enter or leave clock gated state. */
++ u64 enable;
++
++ /* If set, enter clock gating state, regardless of custom block's
++ * internal idle state
++ */
++ u64 force_idle;
++};
++
++/* Performance expectation ioctl. */
++enum apex_performance_expectation {
++ APEX_PERFORMANCE_LOW = 0,
++ APEX_PERFORMANCE_MED = 1,
++ APEX_PERFORMANCE_HIGH = 2,
++ APEX_PERFORMANCE_MAX = 3,
++};
++
++struct apex_performance_expectation_ioctl {
++ /* Expected performance from apex. */
++ uint32_t performance;
++};
++
++/* Base number for all Apex-common IOCTLs */
++#define APEX_IOCTL_BASE 0x7F
++
++/* Enable/Disable clock gating. */
++#define APEX_IOCTL_GATE_CLOCK \
++ _IOW(APEX_IOCTL_BASE, 0, struct apex_gate_clock_ioctl)
++
++#define APEX_IOCTL_PERFORMANCE_EXPECTATION _IOW(APEX_IOCTL_BASE, 1, struct apex_performance_expectation_ioctl)
++
++#endif /* __APEX_H__ */
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_constants.h b/drivers/staging/gasket-driver/gasket_constants.h
+--- a/drivers/staging/gasket-driver/gasket_constants.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_constants.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,47 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/* Copyright (C) 2018 Google, Inc. */
++#ifndef __GASKET_CONSTANTS_H__
++#define __GASKET_CONSTANTS_H__
++
++#define GASKET_FRAMEWORK_VERSION "1.1.4"
++
++/*
++ * The maximum number of simultaneous device types supported by the framework.
++ */
++#define GASKET_FRAMEWORK_DESC_MAX 2
++
++/* The maximum devices per each type. */
++#define GASKET_DEV_MAX 256
++
++/* The number of supported (and possible) PCI BARs. */
++#define GASKET_NUM_BARS 6
++
++/* The number of supported Gasket page tables per device. */
++#define GASKET_MAX_NUM_PAGE_TABLES 1
++
++/* Maximum length of device names (driver name + minor number suffix + NULL). */
++#define GASKET_NAME_MAX 32
++
++/* Device status enumeration. */
++enum gasket_status {
++ /*
++ * A device is DEAD if it has not been initialized or has had an error.
++ */
++ GASKET_STATUS_DEAD = 0,
++ /*
++ * A device is LAMED if the hardware is healthy but the kernel was
++ * unable to enable some functionality (e.g. interrupts).
++ */
++ GASKET_STATUS_LAMED,
++
++ /* A device is ALIVE if it is ready for operation. */
++ GASKET_STATUS_ALIVE,
++
++ /*
++ * This status is set when the driver is exiting and waiting for all
++ * handles to be closed.
++ */
++ GASKET_STATUS_DRIVER_EXIT,
++};
++
++#endif
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_core.c b/drivers/staging/gasket-driver/gasket_core.c
+--- a/drivers/staging/gasket-driver/gasket_core.c 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_core.c 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,1936 @@
++// SPDX-License-Identifier: GPL-2.0
++/*
++ * Gasket generic driver framework. This file contains the implementation
++ * for the Gasket generic driver framework - the functionality that is common
++ * across Gasket devices.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++
++#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
++
++#include "gasket_core.h"
++
++#include "gasket_interrupt.h"
++#include "gasket_ioctl.h"
++#include "gasket_page_table.h"
++#include "gasket_sysfs.h"
++
++#include <linux/capability.h>
++#include <linux/compiler.h>
++#include <linux/delay.h>
++#include <linux/device.h>
++#include <linux/fs.h>
++#include <linux/init.h>
++#include <linux/of.h>
++#include <linux/pid_namespace.h>
++#include <linux/platform_device.h>
++#include <linux/printk.h>
++#include <linux/sched.h>
++#include <linux/version.h>
++
++#ifdef GASKET_KERNEL_TRACE_SUPPORT
++#define CREATE_TRACE_POINTS
++#include <trace/events/gasket_mmap.h>
++#else
++#define trace_gasket_mmap_exit(x)
++#define trace_gasket_mmap_entry(x, ...)
++#endif
++
++/*
++ * "Private" members of gasket_driver_desc.
++ *
++ * Contains internal per-device type tracking data, i.e., data not appropriate
++ * as part of the public interface for the generic framework.
++ */
++struct gasket_internal_desc {
++ /* Device-specific-driver-provided configuration information. */
++ const struct gasket_driver_desc *driver_desc;
++
++ /* Protects access to per-driver data (i.e. this structure). */
++ struct mutex mutex;
++
++ /* Kernel-internal device class. */
++ struct class *class;
++
++ /* Instantiated / present devices of this type. */
++ struct gasket_dev *devs[GASKET_DEV_MAX];
++};
++
++/* do_map_region() needs be able to return more than just true/false. */
++enum do_map_region_status {
++ /* The region was successfully mapped. */
++ DO_MAP_REGION_SUCCESS,
++
++ /* Attempted to map region and failed. */
++ DO_MAP_REGION_FAILURE,
++
++ /* The requested region to map was not part of a mappable region. */
++ DO_MAP_REGION_INVALID,
++};
++
++/* Global data definitions. */
++/* Mutex - only for framework-wide data. Other data should be protected by
++ * finer-grained locks.
++ */
++static DEFINE_MUTEX(g_mutex);
++
++/* List of all registered device descriptions & their supporting data. */
++static struct gasket_internal_desc g_descs[GASKET_FRAMEWORK_DESC_MAX];
++
++/* Mapping of statuses to human-readable strings. Must end with {0,NULL}. */
++static const struct gasket_num_name gasket_status_name_table[] = {
++ { GASKET_STATUS_DEAD, "DEAD" },
++ { GASKET_STATUS_ALIVE, "ALIVE" },
++ { GASKET_STATUS_LAMED, "LAMED" },
++ { GASKET_STATUS_DRIVER_EXIT, "DRIVER_EXITING" },
++ { 0, NULL },
++};
++
++/* Enumeration of the automatic Gasket framework sysfs nodes. */
++enum gasket_sysfs_attribute_type {
++ ATTR_BAR_OFFSETS,
++ ATTR_BAR_SIZES,
++ ATTR_DRIVER_VERSION,
++ ATTR_FRAMEWORK_VERSION,
++ ATTR_DEVICE_TYPE,
++ ATTR_HARDWARE_REVISION,
++ ATTR_PCI_ADDRESS,
++ ATTR_STATUS,
++ ATTR_IS_DEVICE_OWNED,
++ ATTR_DEVICE_OWNER,
++ ATTR_WRITE_OPEN_COUNT,
++ ATTR_RESET_COUNT,
++ ATTR_USER_MEM_RANGES
++};
++
++/* On some arm64 systems pcie dma controller can only access lower 4GB of
++ * addresses. Unfortunately vendor BSP isn't providing any means of determining
++ * this limitation and there're no errors reported if access to higher addresses
++ * if being done. This parameter allows to workaround this issue by pretending
++ * that our device only supports 32 bit addresses. This in turn will cause
++ * dma driver to use shadow buffers located in low 32 bit address space.
++ */
++static int dma_bit_mask = 64;
++module_param(dma_bit_mask, int, 0644);
++
++/* Perform a standard Gasket callback. */
++static inline int
++check_and_invoke_callback(struct gasket_dev *gasket_dev,
++ int (*cb_function)(struct gasket_dev *))
++{
++ int ret = 0;
++
++ if (cb_function) {
++ mutex_lock(&gasket_dev->mutex);
++ ret = cb_function(gasket_dev);
++ mutex_unlock(&gasket_dev->mutex);
++ }
++ return ret;
++}
++
++/* Perform a standard Gasket callback without grabbing gasket_dev->mutex. */
++static inline int
++gasket_check_and_invoke_callback_nolock(struct gasket_dev *gasket_dev,
++ int (*cb_function)(struct gasket_dev *))
++{
++ int ret = 0;
++
++ if (cb_function)
++ ret = cb_function(gasket_dev);
++ return ret;
++}
++
++/*
++ * Return nonzero if the gasket_cdev_info is owned by the current thread group
++ * ID.
++ */
++static int gasket_owned_by_current_tgid(struct gasket_cdev_info *info)
++{
++ return (info->ownership.is_owned &&
++ (info->ownership.owner == current->tgid));
++}
++
++/*
++ * Find the next free gasket_internal_dev slot.
++ *
++ * Returns the located slot number on success or a negative number on failure.
++ */
++static int gasket_find_dev_slot(struct gasket_internal_desc *internal_desc,
++ const char *kobj_name)
++{
++ int i;
++
++ mutex_lock(&internal_desc->mutex);
++
++ /* Search for a previous instance of this device. */
++ for (i = 0; i < GASKET_DEV_MAX; i++) {
++ if (internal_desc->devs[i] &&
++ strcmp(internal_desc->devs[i]->kobj_name, kobj_name) == 0) {
++ pr_err("Duplicate device %s\n", kobj_name);
++ mutex_unlock(&internal_desc->mutex);
++ return -EBUSY;
++ }
++ }
++
++ /* Find a free device slot. */
++ for (i = 0; i < GASKET_DEV_MAX; i++) {
++ if (!internal_desc->devs[i])
++ break;
++ }
++
++ if (i == GASKET_DEV_MAX) {
++ pr_err("Too many registered devices; max %d\n", GASKET_DEV_MAX);
++ mutex_unlock(&internal_desc->mutex);
++ return -EBUSY;
++ }
++
++ mutex_unlock(&internal_desc->mutex);
++ return i;
++}
++
++/*
++ * Allocate and initialize a Gasket device structure, add the device to the
++ * device list.
++ *
++ * Returns 0 if successful, a negative error code otherwise.
++ */
++static int gasket_alloc_dev(struct gasket_internal_desc *internal_desc,
++ struct device *parent, struct gasket_dev **pdev)
++{
++ int dev_idx;
++ const struct gasket_driver_desc *driver_desc =
++ internal_desc->driver_desc;
++ struct gasket_dev *gasket_dev;
++ struct gasket_cdev_info *dev_info;
++ const char *parent_name = dev_name(parent);
++
++ pr_debug("Allocating a Gasket device, parent %s.\n", parent_name);
++
++ *pdev = NULL;
++
++ dev_idx = gasket_find_dev_slot(internal_desc, parent_name);
++ if (dev_idx < 0)
++ return dev_idx;
++
++ gasket_dev = *pdev = kzalloc(sizeof(*gasket_dev), GFP_KERNEL);
++ if (!gasket_dev) {
++ pr_err("no memory for device, parent %s\n", parent_name);
++ return -ENOMEM;
++ }
++ internal_desc->devs[dev_idx] = gasket_dev;
++
++ mutex_init(&gasket_dev->mutex);
++
++ gasket_dev->internal_desc = internal_desc;
++ gasket_dev->dev_idx = dev_idx;
++ snprintf(gasket_dev->kobj_name, GASKET_NAME_MAX, "%s", parent_name);
++ gasket_dev->dev = get_device(parent);
++ gasket_dev->dma_dev = get_device(parent);
++ /* gasket_bar_data is uninitialized. */
++ gasket_dev->num_page_tables = driver_desc->num_page_tables;
++ /* max_page_table_size and *page table are uninit'ed */
++ /* interrupt_data is not initialized. */
++ /* status is 0, or GASKET_STATUS_DEAD */
++
++ dev_info = &gasket_dev->dev_info;
++ snprintf(dev_info->name, GASKET_NAME_MAX, "%s_%u", driver_desc->name,
++ gasket_dev->dev_idx);
++ dev_info->devt =
++ MKDEV(driver_desc->major, driver_desc->minor +
++ gasket_dev->dev_idx);
++ dev_info->device =
++ device_create(internal_desc->class, parent, dev_info->devt,
++ gasket_dev, dev_info->name);
++
++ /* cdev has not yet been added; cdev_added is 0 */
++ dev_info->gasket_dev_ptr = gasket_dev;
++ /* ownership is all 0, indicating no owner or opens. */
++
++ return 0;
++}
++
++/* Free a Gasket device. */
++static void gasket_free_dev(struct gasket_dev *gasket_dev)
++{
++ struct gasket_internal_desc *internal_desc = gasket_dev->internal_desc;
++
++ mutex_lock(&internal_desc->mutex);
++ internal_desc->devs[gasket_dev->dev_idx] = NULL;
++ mutex_unlock(&internal_desc->mutex);
++ put_device(gasket_dev->dev);
++ put_device(gasket_dev->dma_dev);
++ kfree(gasket_dev);
++}
++
++/*
++ * Maps the specified bar into kernel space.
++ *
++ * Returns 0 on success, a negative error code otherwise.
++ * A zero-sized BAR will not be mapped, but is not an error.
++ */
++static int gasket_map_pci_bar(struct gasket_dev *gasket_dev, int bar_num)
++{
++ struct gasket_internal_desc *internal_desc = gasket_dev->internal_desc;
++ const struct gasket_driver_desc *driver_desc =
++ internal_desc->driver_desc;
++ ulong desc_bytes = driver_desc->bar_descriptions[bar_num].size;
++ int ret;
++
++ if (desc_bytes == 0)
++ return 0;
++
++ if (driver_desc->bar_descriptions[bar_num].type != PCI_BAR) {
++ /* not PCI: skip this entry */
++ return 0;
++ }
++ /*
++ * pci_resource_start and pci_resource_len return a "resource_size_t",
++ * which is safely castable to ulong (which itself is the arg to
++ * request_mem_region).
++ */
++ gasket_dev->bar_data[bar_num].phys_base =
++ (ulong)pci_resource_start(gasket_dev->pci_dev, bar_num);
++ if (!gasket_dev->bar_data[bar_num].phys_base) {
++ dev_err(gasket_dev->dev, "Cannot get BAR%u base address\n",
++ bar_num);
++ return -EINVAL;
++ }
++
++ gasket_dev->bar_data[bar_num].length_bytes =
++ (ulong)pci_resource_len(gasket_dev->pci_dev, bar_num);
++ if (gasket_dev->bar_data[bar_num].length_bytes < desc_bytes) {
++ dev_err(gasket_dev->dev,
++ "PCI BAR %u space is too small: %lu; expected >= %lu\n",
++ bar_num, gasket_dev->bar_data[bar_num].length_bytes,
++ desc_bytes);
++ return -ENOMEM;
++ }
++
++ if (!request_mem_region(gasket_dev->bar_data[bar_num].phys_base,
++ gasket_dev->bar_data[bar_num].length_bytes,
++ gasket_dev->dev_info.name)) {
++ dev_err(gasket_dev->dev,
++ "Cannot get BAR %d memory region %p\n",
++ bar_num, &gasket_dev->pci_dev->resource[bar_num]);
++ return -EINVAL;
++ }
++
++ gasket_dev->bar_data[bar_num].virt_base =
++ ioremap(gasket_dev->bar_data[bar_num].phys_base,
++ gasket_dev->bar_data[bar_num].length_bytes);
++ if (!gasket_dev->bar_data[bar_num].virt_base) {
++ dev_err(gasket_dev->dev,
++ "Cannot remap BAR %d memory region %p\n",
++ bar_num, &gasket_dev->pci_dev->resource[bar_num]);
++ ret = -ENOMEM;
++ goto fail;
++ }
++
++ dma_set_mask(&gasket_dev->pci_dev->dev, DMA_BIT_MASK(dma_bit_mask));
++ dma_set_coherent_mask(&gasket_dev->pci_dev->dev,
++ DMA_BIT_MASK(dma_bit_mask));
++
++ return 0;
++
++fail:
++ iounmap(gasket_dev->bar_data[bar_num].virt_base);
++ release_mem_region(gasket_dev->bar_data[bar_num].phys_base,
++ gasket_dev->bar_data[bar_num].length_bytes);
++ return ret;
++}
++
++/*
++ * Releases PCI BAR mapping.
++ *
++ * A zero-sized or not-mapped BAR will not be unmapped, but is not an error.
++ */
++static void gasket_unmap_pci_bar(struct gasket_dev *dev, int bar_num)
++{
++ ulong base, bytes;
++ struct gasket_internal_desc *internal_desc = dev->internal_desc;
++ const struct gasket_driver_desc *driver_desc =
++ internal_desc->driver_desc;
++
++ if (driver_desc->bar_descriptions[bar_num].size == 0 ||
++ !dev->bar_data[bar_num].virt_base)
++ return;
++
++ if (driver_desc->bar_descriptions[bar_num].type != PCI_BAR)
++ return;
++
++ iounmap(dev->bar_data[bar_num].virt_base);
++ dev->bar_data[bar_num].virt_base = NULL;
++
++ base = pci_resource_start(dev->pci_dev, bar_num);
++ if (!base) {
++ dev_err(dev->dev, "cannot get PCI BAR%u base address\n",
++ bar_num);
++ return;
++ }
++
++ bytes = pci_resource_len(dev->pci_dev, bar_num);
++ release_mem_region(base, bytes);
++}
++
++/*
++ * Setup PCI memory mapping for the specified device.
++ *
++ * Reads the BAR registers and sets up pointers to the device's memory mapped
++ * IO space.
++ *
++ * Returns 0 on success and a negative value otherwise.
++ */
++static int gasket_setup_pci(struct pci_dev *pci_dev,
++ struct gasket_dev *gasket_dev)
++{
++ int i, mapped_bars, ret;
++
++ for (i = 0; i < GASKET_NUM_BARS; i++) {
++ ret = gasket_map_pci_bar(gasket_dev, i);
++ if (ret) {
++ mapped_bars = i;
++ goto fail;
++ }
++ }
++
++ return 0;
++
++fail:
++ for (i = 0; i < mapped_bars; i++)
++ gasket_unmap_pci_bar(gasket_dev, i);
++
++ return -ENOMEM;
++}
++
++/* Unmaps memory for the specified device. */
++static void gasket_cleanup_pci(struct gasket_dev *gasket_dev)
++{
++ int i;
++
++ for (i = 0; i < GASKET_NUM_BARS; i++)
++ gasket_unmap_pci_bar(gasket_dev, i);
++}
++
++/* Determine the health of the Gasket device. */
++static int gasket_get_hw_status(struct gasket_dev *gasket_dev)
++{
++ int status;
++ int i;
++ const struct gasket_driver_desc *driver_desc =
++ gasket_dev->internal_desc->driver_desc;
++
++ status = gasket_check_and_invoke_callback_nolock(gasket_dev,
++ driver_desc->device_status_cb);
++ if (status != GASKET_STATUS_ALIVE) {
++ dev_dbg(gasket_dev->dev, "Hardware reported status %d.\n",
++ status);
++ return status;
++ }
++
++ status = gasket_interrupt_system_status(gasket_dev);
++ if (status != GASKET_STATUS_ALIVE) {
++ dev_dbg(gasket_dev->dev,
++ "Interrupt system reported status %d.\n", status);
++ return status;
++ }
++
++ for (i = 0; i < driver_desc->num_page_tables; ++i) {
++ status = gasket_page_table_system_status(gasket_dev->page_table[i]);
++ if (status != GASKET_STATUS_ALIVE) {
++ dev_dbg(gasket_dev->dev,
++ "Page table %d reported status %d.\n",
++ i, status);
++ return status;
++ }
++ }
++
++ return GASKET_STATUS_ALIVE;
++}
++
++static ssize_t
++gasket_write_mappable_regions(char *buf,
++ const struct gasket_driver_desc *driver_desc,
++ int bar_index)
++{
++ int i;
++ ssize_t written;
++ ssize_t total_written = 0;
++ ulong min_addr, max_addr;
++ struct gasket_bar_desc bar_desc =
++ driver_desc->bar_descriptions[bar_index];
++
++ if (bar_desc.permissions == GASKET_NOMAP)
++ return 0;
++ for (i = 0;
++ i < bar_desc.num_mappable_regions && total_written < PAGE_SIZE;
++ i++) {
++ min_addr = bar_desc.mappable_regions[i].start -
++ driver_desc->legacy_mmap_address_offset;
++ max_addr = bar_desc.mappable_regions[i].start -
++ driver_desc->legacy_mmap_address_offset +
++ bar_desc.mappable_regions[i].length_bytes;
++ written = scnprintf(buf, PAGE_SIZE - total_written,
++ "0x%08lx-0x%08lx\n", min_addr, max_addr);
++ total_written += written;
++ buf += written;
++ }
++ return total_written;
++}
++
++static ssize_t gasket_sysfs_data_show(struct device *device,
++ struct device_attribute *attr, char *buf)
++{
++ int i, ret = 0;
++ ssize_t current_written = 0;
++ const struct gasket_driver_desc *driver_desc;
++ struct gasket_dev *gasket_dev;
++ struct gasket_sysfs_attribute *gasket_attr;
++ const struct gasket_bar_desc *bar_desc;
++ enum gasket_sysfs_attribute_type sysfs_type;
++
++ gasket_dev = gasket_sysfs_get_device_data(device);
++ if (!gasket_dev) {
++ dev_err(device, "No sysfs mapping found for device\n");
++ return 0;
++ }
++
++ gasket_attr = gasket_sysfs_get_attr(device, attr);
++ if (!gasket_attr) {
++ dev_err(device, "No sysfs attr found for device\n");
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return 0;
++ }
++
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++
++ sysfs_type =
++ (enum gasket_sysfs_attribute_type)gasket_attr->data.attr_type;
++ switch (sysfs_type) {
++ case ATTR_BAR_OFFSETS:
++ for (i = 0; i < GASKET_NUM_BARS; i++) {
++ bar_desc = &driver_desc->bar_descriptions[i];
++ if (bar_desc->size == 0)
++ continue;
++ current_written =
++ snprintf(buf, PAGE_SIZE - ret, "%d: 0x%lx\n", i,
++ (ulong)bar_desc->base);
++ buf += current_written;
++ ret += current_written;
++ }
++ break;
++ case ATTR_BAR_SIZES:
++ for (i = 0; i < GASKET_NUM_BARS; i++) {
++ bar_desc = &driver_desc->bar_descriptions[i];
++ if (bar_desc->size == 0)
++ continue;
++ current_written =
++ snprintf(buf, PAGE_SIZE - ret, "%d: 0x%lx\n", i,
++ (ulong)bar_desc->size);
++ buf += current_written;
++ ret += current_written;
++ }
++ break;
++ case ATTR_DRIVER_VERSION:
++ ret = snprintf(buf, PAGE_SIZE, "%s\n",
++ gasket_dev->internal_desc->driver_desc->driver_version);
++ break;
++ case ATTR_FRAMEWORK_VERSION:
++ ret = snprintf(buf, PAGE_SIZE, "%s\n",
++ GASKET_FRAMEWORK_VERSION);
++ break;
++ case ATTR_DEVICE_TYPE:
++ ret = snprintf(buf, PAGE_SIZE, "%s\n",
++ gasket_dev->internal_desc->driver_desc->name);
++ break;
++ case ATTR_HARDWARE_REVISION:
++ ret = snprintf(buf, PAGE_SIZE, "%d\n",
++ gasket_dev->hardware_revision);
++ break;
++ case ATTR_PCI_ADDRESS:
++ ret = snprintf(buf, PAGE_SIZE, "%s\n", gasket_dev->kobj_name);
++ break;
++ case ATTR_STATUS:
++ ret = snprintf(buf, PAGE_SIZE, "%s\n",
++ gasket_num_name_lookup(gasket_dev->status,
++ gasket_status_name_table));
++ break;
++ case ATTR_IS_DEVICE_OWNED:
++ ret = snprintf(buf, PAGE_SIZE, "%d\n",
++ gasket_dev->dev_info.ownership.is_owned);
++ break;
++ case ATTR_DEVICE_OWNER:
++ ret = snprintf(buf, PAGE_SIZE, "%d\n",
++ gasket_dev->dev_info.ownership.owner);
++ break;
++ case ATTR_WRITE_OPEN_COUNT:
++ ret = snprintf(buf, PAGE_SIZE, "%d\n",
++ gasket_dev->dev_info.ownership.write_open_count);
++ break;
++ case ATTR_RESET_COUNT:
++ ret = snprintf(buf, PAGE_SIZE, "%d\n", gasket_dev->reset_count);
++ break;
++ case ATTR_USER_MEM_RANGES:
++ for (i = 0; i < GASKET_NUM_BARS; ++i) {
++ current_written =
++ gasket_write_mappable_regions(buf, driver_desc,
++ i);
++ buf += current_written;
++ ret += current_written;
++ }
++ break;
++ default:
++ dev_dbg(gasket_dev->dev, "Unknown attribute: %s\n",
++ attr->attr.name);
++ ret = 0;
++ break;
++ }
++
++ gasket_sysfs_put_attr(device, gasket_attr);
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return ret;
++}
++
++/* These attributes apply to all Gasket driver instances. */
++static const struct gasket_sysfs_attribute gasket_sysfs_generic_attrs[] = {
++ GASKET_SYSFS_RO(bar_offsets, gasket_sysfs_data_show, ATTR_BAR_OFFSETS),
++ GASKET_SYSFS_RO(bar_sizes, gasket_sysfs_data_show, ATTR_BAR_SIZES),
++ GASKET_SYSFS_RO(driver_version, gasket_sysfs_data_show,
++ ATTR_DRIVER_VERSION),
++ GASKET_SYSFS_RO(framework_version, gasket_sysfs_data_show,
++ ATTR_FRAMEWORK_VERSION),
++ GASKET_SYSFS_RO(device_type, gasket_sysfs_data_show, ATTR_DEVICE_TYPE),
++ GASKET_SYSFS_RO(revision, gasket_sysfs_data_show,
++ ATTR_HARDWARE_REVISION),
++ GASKET_SYSFS_RO(pci_address, gasket_sysfs_data_show, ATTR_PCI_ADDRESS),
++ GASKET_SYSFS_RO(status, gasket_sysfs_data_show, ATTR_STATUS),
++ GASKET_SYSFS_RO(is_device_owned, gasket_sysfs_data_show,
++ ATTR_IS_DEVICE_OWNED),
++ GASKET_SYSFS_RO(device_owner, gasket_sysfs_data_show,
++ ATTR_DEVICE_OWNER),
++ GASKET_SYSFS_RO(write_open_count, gasket_sysfs_data_show,
++ ATTR_WRITE_OPEN_COUNT),
++ GASKET_SYSFS_RO(reset_count, gasket_sysfs_data_show, ATTR_RESET_COUNT),
++ GASKET_SYSFS_RO(user_mem_ranges, gasket_sysfs_data_show,
++ ATTR_USER_MEM_RANGES),
++ GASKET_END_OF_ATTR_ARRAY
++};
++
++/* Add a char device and related info. */
++static int gasket_add_cdev(struct gasket_cdev_info *dev_info,
++ const struct file_operations *file_ops,
++ struct module *owner)
++{
++ int ret;
++
++ cdev_init(&dev_info->cdev, file_ops);
++ dev_info->cdev.owner = owner;
++ ret = cdev_add(&dev_info->cdev, dev_info->devt, 1);
++ if (ret) {
++ dev_err(dev_info->gasket_dev_ptr->dev,
++ "cannot add char device [ret=%d]\n", ret);
++ return ret;
++ }
++ dev_info->cdev_added = 1;
++
++ return 0;
++}
++
++/* Disable device operations. */
++void gasket_disable_device(struct gasket_dev *gasket_dev)
++{
++ const struct gasket_driver_desc *driver_desc =
++ gasket_dev->internal_desc->driver_desc;
++ int i;
++
++ dev_dbg(gasket_dev->dev, "disabling device\n");
++ /* Only delete the device if it has been successfully added. */
++ if (gasket_dev->dev_info.cdev_added)
++ cdev_del(&gasket_dev->dev_info.cdev);
++
++ gasket_dev->status = GASKET_STATUS_DEAD;
++
++ gasket_interrupt_cleanup(gasket_dev);
++
++ for (i = 0; i < driver_desc->num_page_tables; ++i) {
++ if (gasket_dev->page_table[i]) {
++ gasket_page_table_reset(gasket_dev->page_table[i]);
++ gasket_page_table_cleanup(gasket_dev->page_table[i]);
++ }
++ }
++}
++EXPORT_SYMBOL(gasket_disable_device);
++
++/*
++ * Registered driver descriptor lookup for PCI devices.
++ *
++ * Precondition: Called with g_mutex held (to avoid a race on return).
++ * Returns NULL if no matching device was found.
++ */
++static struct gasket_internal_desc *
++lookup_pci_internal_desc(struct pci_dev *pci_dev)
++{
++ int i;
++
++ __must_hold(&g_mutex);
++ for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
++ if (g_descs[i].driver_desc &&
++ g_descs[i].driver_desc->pci_id_table &&
++ pci_match_id(g_descs[i].driver_desc->pci_id_table, pci_dev))
++ return &g_descs[i];
++ }
++
++ return NULL;
++}
++
++/*
++ * Registered driver descriptor lookup for platform devices.
++ * Caller must hold g_mutex.
++ */
++static struct gasket_internal_desc *
++lookup_platform_internal_desc(struct platform_device *pdev)
++{
++ int i;
++
++ __must_hold(&g_mutex);
++ for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
++ if (g_descs[i].driver_desc &&
++ strcmp(g_descs[i].driver_desc->name, pdev->name) == 0)
++ return &g_descs[i];
++ }
++
++ return NULL;
++}
++
++/*
++ * Verifies that the user has permissions to perform the requested mapping and
++ * that the provided descriptor/range is of adequate size to hold the range to
++ * be mapped.
++ */
++static bool gasket_mmap_has_permissions(struct gasket_dev *gasket_dev,
++ struct vm_area_struct *vma,
++ int bar_permissions)
++{
++ int requested_permissions;
++ /* Always allow sysadmin to access. */
++ if (capable(CAP_SYS_ADMIN))
++ return true;
++
++ /* Never allow non-sysadmins to access to a dead device. */
++ if (gasket_dev->status != GASKET_STATUS_ALIVE) {
++ dev_dbg(gasket_dev->dev, "Device is dead.\n");
++ return false;
++ }
++
++ /* Make sure that no wrong flags are set. */
++ requested_permissions =
++ (vma->vm_flags & (VM_WRITE | VM_READ | VM_EXEC));
++ if (requested_permissions & ~(bar_permissions)) {
++ dev_dbg(gasket_dev->dev,
++ "Attempting to map a region with requested permissions "
++ "0x%x, but region has permissions 0x%x.\n",
++ requested_permissions, bar_permissions);
++ return false;
++ }
++
++ /* Do not allow a non-owner to write. */
++ if ((vma->vm_flags & VM_WRITE) &&
++ !gasket_owned_by_current_tgid(&gasket_dev->dev_info)) {
++ dev_dbg(gasket_dev->dev,
++ "Attempting to mmap a region for write without owning "
++ "device.\n");
++ return false;
++ }
++
++ return true;
++}
++
++/*
++ * Verifies that the input address is within the region allocated to coherent
++ * buffer.
++ */
++static bool
++gasket_is_coherent_region(const struct gasket_driver_desc *driver_desc,
++ ulong address)
++{
++ struct gasket_coherent_buffer_desc coh_buff_desc =
++ driver_desc->coherent_buffer_description;
++
++ if (coh_buff_desc.permissions != GASKET_NOMAP) {
++ if ((address >= coh_buff_desc.base) &&
++ (address < coh_buff_desc.base + coh_buff_desc.size)) {
++ return true;
++ }
++ }
++ return false;
++}
++
++static int gasket_get_bar_index(const struct gasket_dev *gasket_dev,
++ ulong phys_addr)
++{
++ int i;
++ const struct gasket_driver_desc *driver_desc;
++
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++ for (i = 0; i < GASKET_NUM_BARS; ++i) {
++ struct gasket_bar_desc bar_desc =
++ driver_desc->bar_descriptions[i];
++
++ if (bar_desc.permissions != GASKET_NOMAP) {
++ if (phys_addr >= bar_desc.base &&
++ phys_addr < (bar_desc.base + bar_desc.size)) {
++ return i;
++ }
++ }
++ }
++ /* If we haven't found the address by now, it is invalid. */
++ return -EINVAL;
++}
++
++/*
++ * Sets the actual bounds to map, given the device's mappable region.
++ *
++ * Given the device's mappable region, along with the user-requested mapping
++ * start offset and length of the user region, determine how much of this
++ * mappable region can be mapped into the user's region (start/end offsets),
++ * and the physical offset (phys_offset) into the BAR where the mapping should
++ * begin (either the VMA's or region lower bound).
++ *
++ * In other words, this calculates the overlap between the VMA
++ * (bar_offset, requested_length) and the given gasket_mappable_region.
++ *
++ * Returns true if there's anything to map, and false otherwise.
++ */
++static bool
++gasket_mm_get_mapping_addrs(const struct gasket_mappable_region *region,
++ ulong bar_offset, ulong requested_length,
++ struct gasket_mappable_region *mappable_region,
++ ulong *virt_offset)
++{
++ ulong range_start = region->start;
++ ulong range_length = region->length_bytes;
++ ulong range_end = range_start + range_length;
++
++ *virt_offset = 0;
++ if (bar_offset + requested_length < range_start) {
++ /*
++ * If the requested region is completely below the range,
++ * there is nothing to map.
++ */
++ return false;
++ } else if (bar_offset <= range_start) {
++ /* If the bar offset is below this range's start
++ * but the requested length continues into it:
++ * 1) Only map starting from the beginning of this
++ * range's phys. offset, so we don't map unmappable
++ * memory.
++ * 2) The length of the virtual memory to not map is the
++ * delta between the bar offset and the
++ * mappable start (and since the mappable start is
++ * bigger, start - req.)
++ * 3) The map length is the minimum of the mappable
++ * requested length (requested_length - virt_offset)
++ * and the actual mappable length of the range.
++ */
++ mappable_region->start = range_start;
++ *virt_offset = range_start - bar_offset;
++ mappable_region->length_bytes =
++ min(requested_length - *virt_offset, range_length);
++ return true;
++ } else if (bar_offset > range_start &&
++ bar_offset < range_end) {
++ /*
++ * If the bar offset is within this range:
++ * 1) Map starting from the bar offset.
++ * 2) Because there is no forbidden memory between the
++ * bar offset and the range start,
++ * virt_offset is 0.
++ * 3) The map length is the minimum of the requested
++ * length and the remaining length in the buffer
++ * (range_end - bar_offset)
++ */
++ mappable_region->start = bar_offset;
++ *virt_offset = 0;
++ mappable_region->length_bytes =
++ min(requested_length, range_end - bar_offset);
++ return true;
++ }
++
++ /*
++ * If the requested [start] offset is above range_end,
++ * there's nothing to map.
++ */
++ return false;
++}
++
++/*
++ * Calculates the offset where the VMA range begins in its containing BAR.
++ * The offset is written into bar_offset on success.
++ * Returns zero on success, anything else on error.
++ */
++static int gasket_mm_vma_bar_offset(const struct gasket_dev *gasket_dev,
++ const struct vm_area_struct *vma,
++ ulong *bar_offset)
++{
++ ulong raw_offset;
++ int bar_index;
++ const struct gasket_driver_desc *driver_desc =
++ gasket_dev->internal_desc->driver_desc;
++
++ raw_offset = (vma->vm_pgoff << PAGE_SHIFT) +
++ driver_desc->legacy_mmap_address_offset;
++ bar_index = gasket_get_bar_index(gasket_dev, raw_offset);
++ if (bar_index < 0) {
++ dev_err(gasket_dev->dev,
++ "Unable to find matching bar for address 0x%lx\n",
++ raw_offset);
++ trace_gasket_mmap_exit(bar_index);
++ return bar_index;
++ }
++ *bar_offset =
++ raw_offset - driver_desc->bar_descriptions[bar_index].base;
++
++ return 0;
++}
++
++int gasket_mm_unmap_region(const struct gasket_dev *gasket_dev,
++ struct vm_area_struct *vma,
++ const struct gasket_mappable_region *map_region)
++{
++ ulong bar_offset;
++ ulong virt_offset;
++ struct gasket_mappable_region mappable_region;
++ int ret;
++
++ if (map_region->length_bytes == 0)
++ return 0;
++
++ ret = gasket_mm_vma_bar_offset(gasket_dev, vma, &bar_offset);
++ if (ret)
++ return ret;
++
++ if (!gasket_mm_get_mapping_addrs(map_region, bar_offset,
++ vma->vm_end - vma->vm_start,
++ &mappable_region, &virt_offset))
++ return 1;
++
++ /*
++ * The length passed to zap_vma_ptes MUST BE A MULTIPLE OF
++ * PAGE_SIZE! Trust me. I have the scars.
++ *
++ * Next multiple of y: ceil_div(x, y) * y
++ */
++ zap_vma_ptes(vma, vma->vm_start + virt_offset,
++ DIV_ROUND_UP(mappable_region.length_bytes, PAGE_SIZE) *
++ PAGE_SIZE);
++ return 0;
++}
++EXPORT_SYMBOL(gasket_mm_unmap_region);
++
++/* Maps a virtual address + range to a physical offset of a BAR. */
++static enum do_map_region_status
++do_map_region(const struct gasket_dev *gasket_dev, struct vm_area_struct *vma,
++ struct gasket_mappable_region *mappable_region)
++{
++ /* Maximum size of a single call to io_remap_pfn_range. */
++ /* I pulled this number out of thin air. */
++ const ulong max_chunk_size = 64 * 1024 * 1024;
++ ulong chunk_size, mapped_bytes = 0;
++
++ const struct gasket_driver_desc *driver_desc =
++ gasket_dev->internal_desc->driver_desc;
++
++ ulong bar_offset, virt_offset;
++ struct gasket_mappable_region region_to_map;
++ ulong phys_offset, map_length;
++ ulong virt_base, phys_base;
++ int bar_index, ret;
++
++ ret = gasket_mm_vma_bar_offset(gasket_dev, vma, &bar_offset);
++ if (ret)
++ return DO_MAP_REGION_INVALID;
++
++ if (!gasket_mm_get_mapping_addrs(mappable_region, bar_offset,
++ vma->vm_end - vma->vm_start,
++ ®ion_to_map, &virt_offset))
++ return DO_MAP_REGION_INVALID;
++ phys_offset = region_to_map.start;
++ map_length = region_to_map.length_bytes;
++
++ virt_base = vma->vm_start + virt_offset;
++ bar_index =
++ gasket_get_bar_index(gasket_dev,
++ (vma->vm_pgoff << PAGE_SHIFT) +
++ driver_desc->legacy_mmap_address_offset);
++ phys_base = gasket_dev->bar_data[bar_index].phys_base + phys_offset;
++ while (mapped_bytes < map_length) {
++ /*
++ * io_remap_pfn_range can take a while, so we chunk its
++ * calls and call cond_resched between each.
++ */
++ chunk_size = min(max_chunk_size, map_length - mapped_bytes);
++
++ cond_resched();
++ ret = io_remap_pfn_range(vma, virt_base + mapped_bytes,
++ (phys_base + mapped_bytes) >>
++ PAGE_SHIFT, chunk_size,
++ vma->vm_page_prot);
++ if (ret) {
++ dev_err(gasket_dev->dev,
++ "Error remapping PFN range.\n");
++ goto fail;
++ }
++ mapped_bytes += chunk_size;
++ }
++
++ return DO_MAP_REGION_SUCCESS;
++
++fail:
++ /* Unmap the partial chunk we mapped. */
++ mappable_region->length_bytes = mapped_bytes;
++ if (gasket_mm_unmap_region(gasket_dev, vma, mappable_region))
++ dev_err(gasket_dev->dev,
++ "Error unmapping partial region 0x%lx (0x%lx bytes)\n",
++ (ulong)virt_offset,
++ (ulong)mapped_bytes);
++
++ return DO_MAP_REGION_FAILURE;
++}
++
++/* Map a region of coherent memory. */
++static int gasket_mmap_coherent(struct gasket_dev *gasket_dev,
++ struct vm_area_struct *vma)
++{
++ const struct gasket_driver_desc *driver_desc =
++ gasket_dev->internal_desc->driver_desc;
++ const ulong requested_length = vma->vm_end - vma->vm_start;
++ int ret;
++ ulong permissions;
++
++ if (requested_length == 0 || requested_length >
++ gasket_dev->coherent_buffer.length_bytes) {
++ trace_gasket_mmap_exit(-EINVAL);
++ return -EINVAL;
++ }
++
++ permissions = driver_desc->coherent_buffer_description.permissions;
++ if (!gasket_mmap_has_permissions(gasket_dev, vma, permissions)) {
++ dev_err(gasket_dev->dev, "Permission checking failed.\n");
++ trace_gasket_mmap_exit(-EPERM);
++ return -EPERM;
++ }
++
++ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
++ vma->vm_pgoff = 0;
++ ret = dma_mmap_coherent(gasket_dev->dma_dev, vma,
++ gasket_dev->coherent_buffer.virt_base,
++ gasket_dev->coherent_buffer.phys_base,
++ requested_length);
++ if (ret) {
++ dev_err(gasket_dev->dev,
++ "Error mmapping coherent buffer err=%d.\n", ret);
++ trace_gasket_mmap_exit(ret);
++ return ret;
++ }
++
++ /* Record the user virtual to dma_address mapping that was
++ * created by the kernel.
++ */
++ gasket_set_user_virt(gasket_dev, requested_length,
++ gasket_dev->coherent_buffer.phys_base,
++ vma->vm_start);
++ return 0;
++}
++
++/* Map a device's BARs into user space. */
++static int gasket_mmap(struct file *filp, struct vm_area_struct *vma)
++{
++ int i, ret;
++ int bar_index;
++ int has_mapped_anything = 0;
++ ulong permissions;
++ ulong raw_offset, vma_size;
++ bool is_coherent_region;
++ const struct gasket_driver_desc *driver_desc;
++ struct gasket_dev *gasket_dev = (struct gasket_dev *)filp->private_data;
++ const struct gasket_bar_desc *bar_desc;
++ struct gasket_mappable_region *map_regions = NULL;
++ int num_map_regions = 0;
++ enum do_map_region_status map_status;
++
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++
++ if (vma->vm_start & ~PAGE_MASK) {
++ dev_err(gasket_dev->dev,
++ "Base address not page-aligned: 0x%lx\n",
++ vma->vm_start);
++ trace_gasket_mmap_exit(-EINVAL);
++ return -EINVAL;
++ }
++
++ /* Calculate the offset of this range into physical mem. */
++ raw_offset = (vma->vm_pgoff << PAGE_SHIFT) +
++ driver_desc->legacy_mmap_address_offset;
++ vma_size = vma->vm_end - vma->vm_start;
++ trace_gasket_mmap_entry(gasket_dev->dev_info.name, raw_offset,
++ vma_size);
++
++ /*
++ * Check if the raw offset is within a bar region. If not, check if it
++ * is a coherent region.
++ */
++ bar_index = gasket_get_bar_index(gasket_dev, raw_offset);
++ is_coherent_region = gasket_is_coherent_region(driver_desc, raw_offset);
++ if (bar_index < 0 && !is_coherent_region) {
++ dev_err(gasket_dev->dev,
++ "Unable to find matching bar for address 0x%lx\n",
++ raw_offset);
++ trace_gasket_mmap_exit(bar_index);
++ return bar_index;
++ }
++ if (bar_index > 0 && is_coherent_region) {
++ dev_err(gasket_dev->dev,
++ "double matching bar and coherent buffers for address "
++ "0x%lx\n",
++ raw_offset);
++ trace_gasket_mmap_exit(bar_index);
++ return -EINVAL;
++ }
++
++ vma->vm_private_data = gasket_dev;
++
++ if (is_coherent_region)
++ return gasket_mmap_coherent(gasket_dev, vma);
++
++ /* Everything in the rest of this function is for normal BAR mapping. */
++
++ /*
++ * Subtract the base of the bar from the raw offset to get the
++ * memory location within the bar to map.
++ */
++ bar_desc = &driver_desc->bar_descriptions[bar_index];
++ permissions = bar_desc->permissions;
++ if (!gasket_mmap_has_permissions(gasket_dev, vma, permissions)) {
++ dev_err(gasket_dev->dev, "Permission checking failed.\n");
++ trace_gasket_mmap_exit(-EPERM);
++ return -EPERM;
++ }
++
++ if (driver_desc->get_mappable_regions_cb) {
++ ret = driver_desc->get_mappable_regions_cb(gasket_dev,
++ bar_index,
++ &map_regions,
++ &num_map_regions);
++ if (ret)
++ return ret;
++ } else {
++ if (!gasket_mmap_has_permissions(gasket_dev, vma,
++ bar_desc->permissions)) {
++ dev_err(gasket_dev->dev,
++ "Permission checking failed.\n");
++ trace_gasket_mmap_exit(-EPERM);
++ return -EPERM;
++ }
++ num_map_regions = bar_desc->num_mappable_regions;
++ map_regions = kcalloc(num_map_regions,
++ sizeof(*bar_desc->mappable_regions),
++ GFP_KERNEL);
++ if (map_regions) {
++ memcpy(map_regions, bar_desc->mappable_regions,
++ num_map_regions *
++ sizeof(*bar_desc->mappable_regions));
++ }
++ }
++
++ if (!map_regions || num_map_regions == 0) {
++ dev_err(gasket_dev->dev, "No mappable regions returned!\n");
++ return -EINVAL;
++ }
++
++ /* Marks the VMA's pages as uncacheable. */
++ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
++ for (i = 0; i < num_map_regions; i++) {
++ map_status = do_map_region(gasket_dev, vma, &map_regions[i]);
++ /* Try the next region if this one was not mappable. */
++ if (map_status == DO_MAP_REGION_INVALID)
++ continue;
++ if (map_status == DO_MAP_REGION_FAILURE) {
++ ret = -ENOMEM;
++ goto fail;
++ }
++
++ has_mapped_anything = 1;
++ }
++
++ kfree(map_regions);
++
++ /* If we could not map any memory, the request was invalid. */
++ if (!has_mapped_anything) {
++ dev_err(gasket_dev->dev,
++ "Map request did not contain a valid region.\n");
++ trace_gasket_mmap_exit(-EINVAL);
++ return -EINVAL;
++ }
++
++ trace_gasket_mmap_exit(0);
++ return 0;
++
++fail:
++ /* Need to unmap any mapped ranges. */
++ num_map_regions = i;
++ for (i = 0; i < num_map_regions; i++)
++ if (gasket_mm_unmap_region(gasket_dev, vma,
++ &bar_desc->mappable_regions[i]))
++ dev_err(gasket_dev->dev, "Error unmapping range %d.\n",
++ i);
++ kfree(map_regions);
++
++ return ret;
++}
++
++/*
++ * Open the char device file.
++ *
++ * If the open is for writing, and the device is not owned, this process becomes
++ * the owner. If the open is for writing and the device is already owned by
++ * some other process, it is an error. If this process is the owner, increment
++ * the open count.
++ *
++ * Returns 0 if successful, a negative error number otherwise.
++ */
++static int gasket_open(struct inode *inode, struct file *filp)
++{
++ int ret;
++ struct gasket_dev *gasket_dev;
++ const struct gasket_driver_desc *driver_desc;
++ struct gasket_ownership *ownership;
++ char task_name[TASK_COMM_LEN];
++ struct gasket_cdev_info *dev_info =
++ container_of(inode->i_cdev, struct gasket_cdev_info, cdev);
++ struct pid_namespace *pid_ns = task_active_pid_ns(current);
++ bool is_root = ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN);
++
++ gasket_dev = dev_info->gasket_dev_ptr;
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++ ownership = &dev_info->ownership;
++ get_task_comm(task_name, current);
++ filp->private_data = gasket_dev;
++ inode->i_size = 0;
++
++ dev_dbg(gasket_dev->dev,
++ "Attempting to open with tgid %u (%s) (f_mode: 0%03o, "
++ "fmode_write: %d is_root: %u)\n",
++ current->tgid, task_name, filp->f_mode,
++ (filp->f_mode & FMODE_WRITE), is_root);
++
++ /* Always allow non-writing accesses. */
++ if (!(filp->f_mode & FMODE_WRITE)) {
++ dev_dbg(gasket_dev->dev, "Allowing read-only opening.\n");
++ return 0;
++ }
++
++ mutex_lock(&gasket_dev->mutex);
++
++ dev_dbg(gasket_dev->dev,
++ "Current owner open count (owning tgid %u): %d.\n",
++ ownership->owner, ownership->write_open_count);
++
++ /* Opening a node owned by another TGID is an error (unless root) */
++ if (ownership->is_owned && ownership->owner != current->tgid &&
++ !is_root) {
++ dev_err(gasket_dev->dev,
++ "Process %u is opening a node held by %u.\n",
++ current->tgid, ownership->owner);
++ mutex_unlock(&gasket_dev->mutex);
++ return -EPERM;
++ }
++
++ /* If the node is not owned, assign it to the current TGID. */
++ if (!ownership->is_owned) {
++ ret = gasket_check_and_invoke_callback_nolock(gasket_dev,
++ driver_desc->device_open_cb);
++ if (ret) {
++ dev_err(gasket_dev->dev,
++ "Error in device open cb: %d\n", ret);
++ mutex_unlock(&gasket_dev->mutex);
++ return ret;
++ }
++ ownership->is_owned = 1;
++ ownership->owner = current->tgid;
++ dev_dbg(gasket_dev->dev, "Device owner is now tgid %u\n",
++ ownership->owner);
++ }
++
++ ownership->write_open_count++;
++
++ dev_dbg(gasket_dev->dev, "New open count (owning tgid %u): %d\n",
++ ownership->owner, ownership->write_open_count);
++
++ mutex_unlock(&gasket_dev->mutex);
++ return 0;
++}
++
++/*
++ * Called on a close of the device file. If this process is the owner,
++ * decrement the open count. On last close by the owner, free up buffers and
++ * eventfd contexts, and release ownership.
++ *
++ * Returns 0 if successful, a negative error number otherwise.
++ */
++static int gasket_release(struct inode *inode, struct file *file)
++{
++ int i;
++ struct gasket_dev *gasket_dev;
++ struct gasket_ownership *ownership;
++ const struct gasket_driver_desc *driver_desc;
++ char task_name[TASK_COMM_LEN];
++ struct gasket_cdev_info *dev_info =
++ container_of(inode->i_cdev, struct gasket_cdev_info, cdev);
++ struct pid_namespace *pid_ns = task_active_pid_ns(current);
++ bool is_root = ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN);
++
++ gasket_dev = dev_info->gasket_dev_ptr;
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++ ownership = &dev_info->ownership;
++ get_task_comm(task_name, current);
++ mutex_lock(&gasket_dev->mutex);
++
++ dev_dbg(gasket_dev->dev,
++ "Releasing device node. Call origin: tgid %u (%s) "
++ "(f_mode: 0%03o, fmode_write: %d, is_root: %u)\n",
++ current->tgid, task_name, file->f_mode,
++ (file->f_mode & FMODE_WRITE), is_root);
++ dev_dbg(gasket_dev->dev, "Current open count (owning tgid %u): %d\n",
++ ownership->owner, ownership->write_open_count);
++
++ if (file->f_mode & FMODE_WRITE) {
++ ownership->write_open_count--;
++ if (ownership->write_open_count == 0) {
++ dev_dbg(gasket_dev->dev, "Device is now free\n");
++ ownership->is_owned = 0;
++ ownership->owner = 0;
++
++ /* Forces chip reset before we unmap the page tables. */
++ driver_desc->device_reset_cb(gasket_dev);
++
++ for (i = 0; i < driver_desc->num_page_tables; ++i) {
++ gasket_page_table_unmap_all(gasket_dev->page_table[i]);
++ gasket_page_table_garbage_collect(gasket_dev->page_table[i]);
++ gasket_free_coherent_memory_all(gasket_dev, i);
++ }
++
++ /* Closes device, enters power save. */
++ gasket_check_and_invoke_callback_nolock(gasket_dev,
++ driver_desc->device_close_cb);
++ }
++ }
++
++ dev_dbg(gasket_dev->dev, "New open count (owning tgid %u): %d\n",
++ ownership->owner, ownership->write_open_count);
++ mutex_unlock(&gasket_dev->mutex);
++ return 0;
++}
++
++/*
++ * Gasket ioctl dispatch function.
++ *
++ * Check if the ioctl is a generic ioctl. If not, pass the ioctl to the
++ * ioctl_handler_cb registered in the driver description.
++ * If the ioctl is a generic ioctl, pass it to gasket_ioctl_handler.
++ */
++static long gasket_ioctl(struct file *filp, uint cmd, ulong arg)
++{
++ struct gasket_dev *gasket_dev;
++ const struct gasket_driver_desc *driver_desc;
++ void __user *argp = (void __user *)arg;
++ char path[256];
++
++ gasket_dev = (struct gasket_dev *)filp->private_data;
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++ if (!driver_desc) {
++ dev_dbg(gasket_dev->dev,
++ "Unable to find device descriptor for file %s\n",
++ d_path(&filp->f_path, path, 256));
++ return -ENODEV;
++ }
++
++ if (!gasket_is_supported_ioctl(cmd)) {
++ /*
++ * The ioctl handler is not a standard Gasket callback, since
++ * it requires different arguments. This means we can't use
++ * check_and_invoke_callback.
++ */
++ if (driver_desc->ioctl_handler_cb)
++ return driver_desc->ioctl_handler_cb(filp, cmd, argp);
++
++ dev_dbg(gasket_dev->dev, "Received unknown ioctl 0x%x\n", cmd);
++ return -EINVAL;
++ }
++
++ return gasket_handle_ioctl(filp, cmd, argp);
++}
++
++/* File operations for all Gasket devices. */
++static const struct file_operations gasket_file_ops = {
++ .owner = THIS_MODULE,
++ .llseek = no_llseek,
++ .mmap = gasket_mmap,
++ .open = gasket_open,
++ .release = gasket_release,
++ .unlocked_ioctl = gasket_ioctl,
++ .compat_ioctl = gasket_ioctl,
++};
++
++/* Perform final init and marks the device as active. */
++int gasket_enable_device(struct gasket_dev *gasket_dev)
++{
++ int tbl_idx;
++ int ret;
++ const struct gasket_driver_desc *driver_desc =
++ gasket_dev->internal_desc->driver_desc;
++
++ dev_dbg(gasket_dev->dev, "enabling device\n");
++ ret = gasket_interrupt_init(gasket_dev);
++ if (ret) {
++ dev_err(gasket_dev->dev,
++ "Critical failure to allocate interrupts: %d\n", ret);
++ gasket_interrupt_cleanup(gasket_dev);
++ return ret;
++ }
++
++ for (tbl_idx = 0; tbl_idx < driver_desc->num_page_tables; tbl_idx++) {
++ dev_dbg(gasket_dev->dev, "Initializing page table %d.\n",
++ tbl_idx);
++ ret = gasket_page_table_init(&gasket_dev->page_table[tbl_idx],
++ &gasket_dev->bar_data[driver_desc->page_table_bar_index],
++ &driver_desc->page_table_configs[tbl_idx],
++ gasket_dev->dev,
++ gasket_dev->pci_dev);
++ if (ret) {
++ dev_err(gasket_dev->dev,
++ "Couldn't init page table %d: %d\n",
++ tbl_idx, ret);
++ return ret;
++ }
++ /*
++ * Make sure that the page table is clear and set to simple
++ * addresses.
++ */
++ gasket_page_table_reset(gasket_dev->page_table[tbl_idx]);
++ }
++
++ /*
++ * hardware_revision_cb returns a positive integer (the rev) if
++ * successful.)
++ */
++ ret = check_and_invoke_callback(gasket_dev,
++ driver_desc->hardware_revision_cb);
++ if (ret < 0) {
++ dev_err(gasket_dev->dev,
++ "Error getting hardware revision: %d\n", ret);
++ return ret;
++ }
++ gasket_dev->hardware_revision = ret;
++
++ /* device_status_cb returns a device status, not an error code. */
++ gasket_dev->status = gasket_get_hw_status(gasket_dev);
++ if (gasket_dev->status == GASKET_STATUS_DEAD)
++ dev_err(gasket_dev->dev, "Device reported as unhealthy.\n");
++
++ ret = gasket_add_cdev(&gasket_dev->dev_info, &gasket_file_ops,
++ driver_desc->module);
++ if (ret)
++ return ret;
++
++ return 0;
++}
++EXPORT_SYMBOL(gasket_enable_device);
++
++static int __gasket_add_device(struct device *parent_dev,
++ struct gasket_internal_desc *internal_desc,
++ struct gasket_dev **gasket_devp)
++{
++ int ret;
++ struct gasket_dev *gasket_dev;
++ const struct gasket_driver_desc *driver_desc =
++ internal_desc->driver_desc;
++
++ ret = gasket_alloc_dev(internal_desc, parent_dev, &gasket_dev);
++ if (ret)
++ return ret;
++ if (IS_ERR(gasket_dev->dev_info.device)) {
++ dev_err(parent_dev, "Cannot create %s device %s [ret = %ld]\n",
++ driver_desc->name, gasket_dev->dev_info.name,
++ PTR_ERR(gasket_dev->dev_info.device));
++ ret = -ENODEV;
++ goto free_gasket_dev;
++ }
++
++ ret = gasket_sysfs_create_mapping(gasket_dev->dev_info.device,
++ gasket_dev);
++ if (ret)
++ goto remove_device;
++
++ ret = gasket_sysfs_create_entries(gasket_dev->dev_info.device,
++ gasket_sysfs_generic_attrs);
++ if (ret)
++ goto remove_sysfs_mapping;
++
++ *gasket_devp = gasket_dev;
++ return 0;
++
++remove_sysfs_mapping:
++ gasket_sysfs_remove_mapping(gasket_dev->dev_info.device);
++remove_device:
++ device_destroy(internal_desc->class, gasket_dev->dev_info.devt);
++free_gasket_dev:
++ gasket_free_dev(gasket_dev);
++ return ret;
++}
++
++static void __gasket_remove_device(struct gasket_internal_desc *internal_desc,
++ struct gasket_dev *gasket_dev)
++{
++ gasket_sysfs_remove_mapping(gasket_dev->dev_info.device);
++ device_destroy(internal_desc->class, gasket_dev->dev_info.devt);
++ gasket_free_dev(gasket_dev);
++}
++
++/*
++ * Add PCI gasket device.
++ *
++ * Called by Gasket device probe function.
++ * Allocates device metadata and maps device memory. The device driver must
++ * call gasket_enable_device after driver init is complete to place the device
++ * in active use.
++ */
++int gasket_pci_add_device(struct pci_dev *pci_dev,
++ struct gasket_dev **gasket_devp)
++{
++ int ret;
++ struct gasket_internal_desc *internal_desc;
++ struct gasket_dev *gasket_dev;
++ struct device *parent;
++
++ dev_dbg(&pci_dev->dev, "add PCI gasket device\n");
++
++ mutex_lock(&g_mutex);
++ internal_desc = lookup_pci_internal_desc(pci_dev);
++ mutex_unlock(&g_mutex);
++ if (!internal_desc) {
++ dev_err(&pci_dev->dev,
++ "PCI add device called for unknown driver type\n");
++ return -ENODEV;
++ }
++
++ parent = &pci_dev->dev;
++ ret = __gasket_add_device(parent, internal_desc, &gasket_dev);
++ if (ret)
++ return ret;
++
++ gasket_dev->pci_dev = pci_dev;
++ ret = gasket_setup_pci(pci_dev, gasket_dev);
++ if (ret)
++ goto cleanup_pci;
++
++ /*
++ * Once we've created the mapping structures successfully, attempt to
++ * create a symlink to the pci directory of this object.
++ */
++ ret = sysfs_create_link(&gasket_dev->dev_info.device->kobj,
++ &pci_dev->dev.kobj, dev_name(&pci_dev->dev));
++ if (ret) {
++ dev_err(gasket_dev->dev,
++ "Cannot create sysfs pci link: %d\n", ret);
++ goto cleanup_pci;
++ }
++
++ *gasket_devp = gasket_dev;
++ return 0;
++
++cleanup_pci:
++ gasket_cleanup_pci(gasket_dev);
++ __gasket_remove_device(internal_desc, gasket_dev);
++ return ret;
++}
++EXPORT_SYMBOL(gasket_pci_add_device);
++
++/* Remove a PCI gasket device. */
++void gasket_pci_remove_device(struct pci_dev *pci_dev)
++{
++ int i;
++ struct gasket_internal_desc *internal_desc;
++ struct gasket_dev *gasket_dev = NULL;
++ /* Find the device desc. */
++ mutex_lock(&g_mutex);
++ internal_desc = lookup_pci_internal_desc(pci_dev);
++ if (!internal_desc) {
++ mutex_unlock(&g_mutex);
++ return;
++ }
++ mutex_unlock(&g_mutex);
++
++ /* Now find the specific device */
++ mutex_lock(&internal_desc->mutex);
++ for (i = 0; i < GASKET_DEV_MAX; i++) {
++ if (internal_desc->devs[i] &&
++ internal_desc->devs[i]->pci_dev == pci_dev) {
++ gasket_dev = internal_desc->devs[i];
++ break;
++ }
++ }
++ mutex_unlock(&internal_desc->mutex);
++
++ if (!gasket_dev)
++ return;
++
++ dev_dbg(gasket_dev->dev, "remove %s PCI gasket device\n",
++ internal_desc->driver_desc->name);
++
++ gasket_cleanup_pci(gasket_dev);
++ __gasket_remove_device(internal_desc, gasket_dev);
++}
++EXPORT_SYMBOL(gasket_pci_remove_device);
++
++/* Add platform gasket device. Called by Gasket device probe function. */
++int gasket_platform_add_device(struct platform_device *pdev,
++ struct gasket_dev **gasket_devp)
++{
++ int ret;
++ struct gasket_internal_desc *internal_desc;
++ struct gasket_dev *gasket_dev;
++ struct device *parent;
++
++ dev_dbg(&pdev->dev, "add platform gasket device\n");
++
++ mutex_lock(&g_mutex);
++ internal_desc = lookup_platform_internal_desc(pdev);
++ mutex_unlock(&g_mutex);
++ if (!internal_desc) {
++ dev_err(&pdev->dev,
++ "%s called for unknown driver type\n", __func__);
++ return -ENODEV;
++ }
++
++ parent = &pdev->dev;
++ ret = __gasket_add_device(parent, internal_desc, &gasket_dev);
++ if (ret)
++ return ret;
++
++ gasket_dev->platform_dev = pdev;
++ *gasket_devp = gasket_dev;
++ return 0;
++}
++EXPORT_SYMBOL(gasket_platform_add_device);
++
++/* Remove a platform gasket device. */
++void gasket_platform_remove_device(struct platform_device *pdev)
++{
++ int i;
++ struct gasket_internal_desc *internal_desc;
++ struct gasket_dev *gasket_dev = NULL;
++
++ /* Find the device desc. */
++ mutex_lock(&g_mutex);
++ internal_desc = lookup_platform_internal_desc(pdev);
++ mutex_unlock(&g_mutex);
++ if (!internal_desc)
++ return;
++
++ /* Now find the specific device */
++ mutex_lock(&internal_desc->mutex);
++ for (i = 0; i < GASKET_DEV_MAX; i++) {
++ if (internal_desc->devs[i] &&
++ internal_desc->devs[i]->platform_dev == pdev) {
++ gasket_dev = internal_desc->devs[i];
++ break;
++ }
++ }
++ mutex_unlock(&internal_desc->mutex);
++
++ if (!gasket_dev)
++ return;
++
++ dev_dbg(gasket_dev->dev, "remove %s platform gasket device\n",
++ internal_desc->driver_desc->name);
++
++ __gasket_remove_device(internal_desc, gasket_dev);
++}
++EXPORT_SYMBOL(gasket_platform_remove_device);
++
++void gasket_set_dma_device(struct gasket_dev *gasket_dev,
++ struct device *dma_dev)
++{
++ put_device(gasket_dev->dma_dev);
++ gasket_dev->dma_dev = get_device(dma_dev);
++}
++EXPORT_SYMBOL(gasket_set_dma_device);
++
++/**
++ * Lookup a name by number in a num_name table.
++ * @num: Number to lookup.
++ * @table: Array of num_name structures, the table for the lookup.
++ *
++ * Description: Searches for num in the table. If found, the
++ * corresponding name is returned; otherwise NULL
++ * is returned.
++ *
++ * The table must have a NULL name pointer at the end.
++ */
++const char *gasket_num_name_lookup(uint num,
++ const struct gasket_num_name *table)
++{
++ uint i = 0;
++
++ while (table[i].snn_name) {
++ if (num == table[i].snn_num)
++ break;
++ ++i;
++ }
++
++ return table[i].snn_name;
++}
++EXPORT_SYMBOL(gasket_num_name_lookup);
++
++int gasket_reset(struct gasket_dev *gasket_dev)
++{
++ int ret;
++
++ mutex_lock(&gasket_dev->mutex);
++ ret = gasket_reset_nolock(gasket_dev);
++ mutex_unlock(&gasket_dev->mutex);
++ return ret;
++}
++EXPORT_SYMBOL(gasket_reset);
++
++int gasket_reset_nolock(struct gasket_dev *gasket_dev)
++{
++ int ret;
++ int i;
++ const struct gasket_driver_desc *driver_desc;
++
++ driver_desc = gasket_dev->internal_desc->driver_desc;
++ if (!driver_desc->device_reset_cb)
++ return 0;
++
++ ret = driver_desc->device_reset_cb(gasket_dev);
++ if (ret) {
++ dev_dbg(gasket_dev->dev, "Device reset cb returned %d.\n",
++ ret);
++ return ret;
++ }
++
++ /* Reinitialize the page tables and interrupt framework. */
++ for (i = 0; i < driver_desc->num_page_tables; ++i)
++ gasket_page_table_reset(gasket_dev->page_table[i]);
++
++ ret = gasket_interrupt_reinit(gasket_dev);
++ if (ret) {
++ dev_dbg(gasket_dev->dev, "Unable to reinit interrupts: %d.\n",
++ ret);
++ return ret;
++ }
++
++ /* Get current device health. */
++ gasket_dev->status = gasket_get_hw_status(gasket_dev);
++ if (gasket_dev->status == GASKET_STATUS_DEAD) {
++ dev_dbg(gasket_dev->dev, "Device reported as dead.\n");
++ return -EINVAL;
++ }
++
++ return 0;
++}
++EXPORT_SYMBOL(gasket_reset_nolock);
++
++gasket_ioctl_permissions_cb_t
++gasket_get_ioctl_permissions_cb(struct gasket_dev *gasket_dev)
++{
++ return gasket_dev->internal_desc->driver_desc->ioctl_permissions_cb;
++}
++EXPORT_SYMBOL(gasket_get_ioctl_permissions_cb);
++
++/* Get the driver structure for a given gasket_dev.
++ * @dev: pointer to gasket_dev, implementing the requested driver.
++ */
++const struct gasket_driver_desc *gasket_get_driver_desc(struct gasket_dev *dev)
++{
++ return dev->internal_desc->driver_desc;
++}
++
++/* Get the device structure for a given gasket_dev.
++ * @dev: pointer to gasket_dev, implementing the requested driver.
++ */
++struct device *gasket_get_device(struct gasket_dev *dev)
++{
++ return dev->dev;
++}
++
++/**
++ * Asynchronously waits on device.
++ * @gasket_dev: Device struct.
++ * @bar: Bar
++ * @offset: Register offset
++ * @mask: Register mask
++ * @val: Expected value
++ * @max_retries: number of sleep periods
++ * @delay_ms: Timeout in milliseconds
++ *
++ * Description: Busy waits for a specific combination of bits to be set on a
++ * Gasket register.
++ **/
++int gasket_wait_with_reschedule(struct gasket_dev *gasket_dev, int bar,
++ u64 offset, u64 mask, u64 val,
++ uint max_retries, u64 delay_ms)
++{
++ uint retries = 0;
++ u64 tmp;
++
++ while (retries < max_retries) {
++ tmp = gasket_dev_read_64(gasket_dev, bar, offset);
++ if ((tmp & mask) == val)
++ return 0;
++ msleep(delay_ms);
++ retries++;
++ }
++ dev_dbg(gasket_dev->dev, "%s timeout: reg %llx timeout (%llu ms)\n",
++ __func__, offset, max_retries * delay_ms);
++ return -ETIMEDOUT;
++}
++EXPORT_SYMBOL(gasket_wait_with_reschedule);
++
++/* See gasket_core.h for description. */
++int gasket_register_device(const struct gasket_driver_desc *driver_desc)
++{
++ int i, ret;
++ int desc_idx = -1;
++ struct gasket_internal_desc *internal;
++
++ pr_debug("Loading %s driver version %s\n", driver_desc->name,
++ driver_desc->driver_version);
++ /* Check for duplicates and find a free slot. */
++ mutex_lock(&g_mutex);
++
++ for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
++ if (g_descs[i].driver_desc == driver_desc) {
++ pr_err("%s driver already loaded/registered\n",
++ driver_desc->name);
++ mutex_unlock(&g_mutex);
++ return -EBUSY;
++ }
++ }
++
++ /* This and the above loop could be combined, but this reads easier. */
++ for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
++ if (!g_descs[i].driver_desc) {
++ g_descs[i].driver_desc = driver_desc;
++ desc_idx = i;
++ break;
++ }
++ }
++ mutex_unlock(&g_mutex);
++
++ if (desc_idx == -1) {
++ pr_err("too many drivers loaded, max %d\n",
++ GASKET_FRAMEWORK_DESC_MAX);
++ return -EBUSY;
++ }
++
++ internal = &g_descs[desc_idx];
++ mutex_init(&internal->mutex);
++ memset(internal->devs, 0, sizeof(struct gasket_dev *) * GASKET_DEV_MAX);
++
++ /* Function signature for `class_create()` is changed in kernel >= 6.4.x
++ * to only accept a single argument.
++ * */
++#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 4, 0)
++ internal->class = class_create(driver_desc->module, driver_desc->name);
++#else
++ internal->class = class_create(driver_desc->name);
++#endif
++
++ if (IS_ERR(internal->class)) {
++ pr_err("Cannot register %s class [ret=%ld]\n",
++ driver_desc->name, PTR_ERR(internal->class));
++ ret = PTR_ERR(internal->class);
++ goto unregister_gasket_driver;
++ }
++
++ ret = register_chrdev_region(MKDEV(driver_desc->major,
++ driver_desc->minor), GASKET_DEV_MAX,
++ driver_desc->name);
++ if (ret) {
++ pr_err("cannot register %s char driver [ret=%d]\n",
++ driver_desc->name, ret);
++ goto destroy_class;
++ }
++
++ return 0;
++
++destroy_class:
++ class_destroy(internal->class);
++
++unregister_gasket_driver:
++ mutex_lock(&g_mutex);
++ g_descs[desc_idx].driver_desc = NULL;
++ mutex_unlock(&g_mutex);
++ return ret;
++}
++EXPORT_SYMBOL(gasket_register_device);
++
++/* See gasket_core.h for description. */
++void gasket_unregister_device(const struct gasket_driver_desc *driver_desc)
++{
++ int i, desc_idx;
++ struct gasket_internal_desc *internal_desc = NULL;
++
++ mutex_lock(&g_mutex);
++ for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
++ if (g_descs[i].driver_desc == driver_desc) {
++ internal_desc = &g_descs[i];
++ desc_idx = i;
++ break;
++ }
++ }
++
++ if (!internal_desc) {
++ mutex_unlock(&g_mutex);
++ pr_err("request to unregister unknown desc: %s, %d:%d\n",
++ driver_desc->name, driver_desc->major,
++ driver_desc->minor);
++ return;
++ }
++
++ unregister_chrdev_region(MKDEV(driver_desc->major, driver_desc->minor),
++ GASKET_DEV_MAX);
++
++ class_destroy(internal_desc->class);
++
++ /* Finally, effectively "remove" the driver. */
++ g_descs[desc_idx].driver_desc = NULL;
++ mutex_unlock(&g_mutex);
++
++ pr_debug("removed %s driver\n", driver_desc->name);
++}
++EXPORT_SYMBOL(gasket_unregister_device);
++
++static int __init gasket_init(void)
++{
++ int i;
++
++ mutex_lock(&g_mutex);
++ for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
++ g_descs[i].driver_desc = NULL;
++ mutex_init(&g_descs[i].mutex);
++ }
++
++ gasket_sysfs_init();
++
++ mutex_unlock(&g_mutex);
++ return 0;
++}
++
++MODULE_DESCRIPTION("Google Gasket driver framework");
++MODULE_VERSION(GASKET_FRAMEWORK_VERSION);
++MODULE_LICENSE("GPL v2");
++MODULE_AUTHOR("Rob Springer <rspringer@google.com>");
++module_init(gasket_init);
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_core.h b/drivers/staging/gasket-driver/gasket_core.h
+--- a/drivers/staging/gasket-driver/gasket_core.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_core.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,657 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/*
++ * Gasket generic driver. Defines the set of data types and functions necessary
++ * to define a driver using the Gasket generic driver framework.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++#ifndef __GASKET_CORE_H__
++#define __GASKET_CORE_H__
++
++#include <linux/cdev.h>
++#include <linux/compiler.h>
++#include <linux/device.h>
++#include <linux/init.h>
++#include <linux/module.h>
++#include <linux/pci.h>
++#include <linux/platform_device.h>
++#include <linux/sched.h>
++#include <linux/slab.h>
++
++#include "gasket_constants.h"
++
++/**
++ * struct gasket_num_name - Map numbers to names.
++ * @ein_num: Number.
++ * @ein_name: Name associated with the number, a char pointer.
++ *
++ * This structure maps numbers to names. It is used to provide printable enum
++ * names, e.g {0, "DEAD"} or {1, "ALIVE"}.
++ */
++struct gasket_num_name {
++ uint snn_num;
++ const char *snn_name;
++};
++
++/*
++ * Register location for packed interrupts.
++ * Each value indicates the location of an interrupt field (in units of
++ * gasket_driver_desc->interrupt_pack_width) within the containing register.
++ * In other words, this indicates the shift to use when creating a mask to
++ * extract/set bits within a register for a given interrupt.
++ */
++enum gasket_interrupt_packing {
++ PACK_0 = 0,
++ PACK_1 = 1,
++ PACK_2 = 2,
++ PACK_3 = 3,
++ UNPACKED = 4,
++};
++
++/* Type of the interrupt supported by the device. */
++enum gasket_interrupt_type {
++ PCI_MSIX = 0,
++ DEVICE_MANAGED = 1, /* Managed externally in device driver */
++};
++
++/*
++ * Used to describe a Gasket interrupt. Contains an interrupt index, a register,
++ * and packing data for that interrupt. The register and packing data
++ * fields are relevant only for PCI_MSIX interrupt type and can be
++ * set to 0 for everything else.
++ */
++struct gasket_interrupt_desc {
++ /* Device-wide interrupt index/number. */
++ int index;
++ /* The register offset controlling this interrupt. */
++ u64 reg;
++ /* The location of this interrupt inside register reg, if packed. */
++ int packing;
++};
++
++/*
++ * This enum is used to identify memory regions being part of the physical
++ * memory that belongs to a device.
++ */
++enum mappable_area_type {
++ PCI_BAR = 0, /* Default */
++ BUS_REGION, /* For SYSBUS devices, i.e. AXI etc... */
++ COHERENT_MEMORY
++};
++
++/*
++ * Metadata for each BAR mapping.
++ * This struct is used so as to track PCI memory, I/O space, AXI and coherent
++ * memory area... i.e. memory objects which can be referenced in the device's
++ * mmap function.
++ */
++struct gasket_bar_data {
++ /* Virtual base address. */
++ u8 __iomem *virt_base;
++
++ /* Physical base address. */
++ ulong phys_base;
++
++ /* Length of the mapping. */
++ ulong length_bytes;
++
++ /* Type of mappable area */
++ enum mappable_area_type type;
++};
++
++/* Maintains device open ownership data. */
++struct gasket_ownership {
++ /* 1 if the device is owned, 0 otherwise. */
++ int is_owned;
++
++ /* TGID of the owner. */
++ pid_t owner;
++
++ /* Count of current device opens in write mode. */
++ int write_open_count;
++};
++
++/* Page table modes of operation. */
++enum gasket_page_table_mode {
++ /* The page table is partitionable as normal, all simple by default. */
++ GASKET_PAGE_TABLE_MODE_NORMAL,
++
++ /* All entries are always simple. */
++ GASKET_PAGE_TABLE_MODE_SIMPLE,
++
++ /* All entries are always extended. No extended bit is used. */
++ GASKET_PAGE_TABLE_MODE_EXTENDED,
++};
++
++/* Page table configuration. One per table. */
++struct gasket_page_table_config {
++ /* The identifier/index of this page table. */
++ int id;
++
++ /* The operation mode of this page table. */
++ enum gasket_page_table_mode mode;
++
++ /* Total (first-level) entries in this page table. */
++ ulong total_entries;
++
++ /* Base register for the page table. */
++ int base_reg;
++
++ /*
++ * Register containing the extended page table. This value is unused in
++ * GASKET_PAGE_TABLE_MODE_SIMPLE and GASKET_PAGE_TABLE_MODE_EXTENDED
++ * modes.
++ */
++ int extended_reg;
++
++ /* The bit index indicating whether a PT entry is extended. */
++ int extended_bit;
++};
++
++/* Maintains information about a device node. */
++struct gasket_cdev_info {
++ /* The internal name of this device. */
++ char name[GASKET_NAME_MAX];
++
++ /* Device number. */
++ dev_t devt;
++
++ /* Kernel-internal device structure. */
++ struct device *device;
++
++ /* Character device for real. */
++ struct cdev cdev;
++
++ /* Flag indicating if cdev_add has been called for the devices. */
++ int cdev_added;
++
++ /* Pointer to the overall gasket_dev struct for this device. */
++ struct gasket_dev *gasket_dev_ptr;
++
++ /* Ownership data for the device in question. */
++ struct gasket_ownership ownership;
++};
++
++/* Describes the offset and length of mmapable device BAR regions. */
++struct gasket_mappable_region {
++ u64 start;
++ u64 length_bytes;
++};
++
++/* Describe the offset, size, and permissions for a device bar. */
++struct gasket_bar_desc {
++ /*
++ * The size of each PCI BAR range, in bytes. If a value is 0, that BAR
++ * will not be mapped into kernel space at all.
++ * For devices with 64 bit BARs, only elements 0, 2, and 4 should be
++ * populated, and 1, 3, and 5 should be set to 0.
++ * For example, for a device mapping 1M in each of the first two 64-bit
++ * BARs, this field would be set as { 0x100000, 0, 0x100000, 0, 0, 0 }
++ * (one number per bar_desc struct.)
++ */
++ u64 size;
++ /* The permissions for this bar. (Should be VM_WRITE/VM_READ/VM_EXEC,
++ * and can be or'd.) If set to GASKET_NOMAP, the bar will
++ * not be used for mmapping.
++ */
++ ulong permissions;
++ /* The memory address corresponding to the base of this bar, if used. */
++ u64 base;
++ /* The number of mappable regions in this bar. */
++ int num_mappable_regions;
++
++ /* The mappable subregions of this bar. */
++ const struct gasket_mappable_region *mappable_regions;
++
++ /* Type of mappable area */
++ enum mappable_area_type type;
++};
++
++/* Describes the offset, size, and permissions for a coherent buffer. */
++struct gasket_coherent_buffer_desc {
++ /* The size of the coherent buffer. */
++ u64 size;
++
++ /* The permissions for this bar. (Should be VM_WRITE/VM_READ/VM_EXEC,
++ * and can be or'd.) If set to GASKET_NOMAP, the bar will
++ * not be used for mmaping.
++ */
++ ulong permissions;
++
++ /* device side address. */
++ u64 base;
++};
++
++/* Coherent buffer structure. */
++struct gasket_coherent_buffer {
++ /* Virtual base address. */
++ u8 __iomem *virt_base;
++
++ /* Physical base address. */
++ dma_addr_t phys_base;
++
++ /* Length of the mapping. */
++ ulong length_bytes;
++};
++
++/* Description of Gasket-specific permissions in the mmap field. */
++enum gasket_mapping_options { GASKET_NOMAP = 0 };
++
++/* This struct represents an undefined bar that should never be mapped. */
++#define GASKET_UNUSED_BAR \
++ { \
++ 0, GASKET_NOMAP, 0, 0, NULL, 0 \
++ }
++
++/* Internal data for a Gasket device. See gasket_core.c for more information. */
++struct gasket_internal_desc;
++
++#define MAX_NUM_COHERENT_PAGES 16
++
++/*
++ * Device data for Gasket device instances.
++ *
++ * This structure contains the data required to manage a Gasket device.
++ */
++struct gasket_dev {
++ /* Pointer to the internal driver description for this device. */
++ struct gasket_internal_desc *internal_desc;
++
++ /* Device info */
++ struct device *dev;
++
++ /* DMA device to use, may be same as above or a parent */
++ struct device *dma_dev;
++
++ /* PCI device pointer for PCI devices */
++ struct pci_dev *pci_dev;
++
++ /* Platform device pointer for platform devices */
++ struct platform_device *platform_dev;
++
++ /* This device's index into internal_desc->devs. */
++ int dev_idx;
++
++ /* The name of this device, as reported by the kernel. */
++ char kobj_name[GASKET_NAME_MAX];
++
++ /* Virtual address of mapped BAR memory range. */
++ struct gasket_bar_data bar_data[GASKET_NUM_BARS];
++
++ /* Coherent buffer. */
++ struct gasket_coherent_buffer coherent_buffer;
++
++ /* Number of page tables for this device. */
++ int num_page_tables;
++
++ /* Address translations. Page tables have a private implementation. */
++ struct gasket_page_table *page_table[GASKET_MAX_NUM_PAGE_TABLES];
++
++ /* Interrupt data for this device. */
++ struct gasket_interrupt_data *interrupt_data;
++
++ /* Status for this device - GASKET_STATUS_ALIVE or _DEAD. */
++ uint status;
++
++ /* Number of times this device has been reset. */
++ uint reset_count;
++
++ /* Dev information for the cdev node. */
++ struct gasket_cdev_info dev_info;
++
++ /* Hardware revision value for this device. */
++ int hardware_revision;
++
++ /* Protects access to per-device data (i.e. this structure). */
++ struct mutex mutex;
++
++ /* cdev hash tracking/membership structure, Accel and legacy. */
++ /* Unused until Accel is upstreamed. */
++ struct hlist_node hlist_node;
++ struct hlist_node legacy_hlist_node;
++};
++
++/* Type of the ioctl handler callback. */
++typedef long (*gasket_ioctl_handler_cb_t)(struct file *file, uint cmd,
++ void __user *argp);
++/* Type of the ioctl permissions check callback. See below. */
++typedef int (*gasket_ioctl_permissions_cb_t)(struct file *filp, uint cmd,
++ void __user *argp);
++
++/*
++ * Device type descriptor.
++ *
++ * This structure contains device-specific data needed to identify and address a
++ * type of device to be administered via the Gasket generic driver.
++ *
++ * Device IDs are per-driver. In other words, two drivers using the Gasket
++ * framework will each have a distinct device 0 (for example).
++ */
++struct gasket_driver_desc {
++ /* The name of this device type. */
++ const char *name;
++
++ /* The name of this specific device model. */
++ const char *chip_model;
++
++ /* The version of the chip specified in chip_model. */
++ const char *chip_version;
++
++ /* The version of this driver: "1.0.0", "2.1.3", etc. */
++ const char *driver_version;
++
++ /*
++ * Non-zero if we should create "legacy" (device and device-class-
++ * specific) character devices and sysfs nodes.
++ */
++ /* Unused until Accel is upstreamed. */
++ int legacy_support;
++
++ /* Major and minor numbers identifying the device. */
++ int major, minor;
++
++ /* Module structure for this driver. */
++ struct module *module;
++
++ /* PCI ID table. */
++ const struct pci_device_id *pci_id_table;
++
++ /* The number of page tables handled by this driver. */
++ int num_page_tables;
++
++ /* The index of the bar containing the page tables. */
++ int page_table_bar_index;
++
++ /* Registers used to control each page table. */
++ const struct gasket_page_table_config *page_table_configs;
++
++ /* The bit index indicating whether a PT entry is extended. */
++ int page_table_extended_bit;
++
++ /*
++ * Legacy mmap address adjusment for legacy devices only. Should be 0
++ * for any new device.
++ */
++ ulong legacy_mmap_address_offset;
++
++ /* Set of 6 bar descriptions that describe all PCIe bars.
++ * Note that BUS/AXI devices (i.e. non PCI devices) use those.
++ */
++ struct gasket_bar_desc bar_descriptions[GASKET_NUM_BARS];
++
++ /*
++ * Coherent buffer description.
++ */
++ struct gasket_coherent_buffer_desc coherent_buffer_description;
++
++ /* Interrupt type. (One of gasket_interrupt_type). */
++ int interrupt_type;
++
++ /* Index of the bar containing the interrupt registers to program. */
++ int interrupt_bar_index;
++
++ /* Number of interrupts in the gasket_interrupt_desc array */
++ int num_interrupts;
++
++ /* Description of the interrupts for this device. */
++ const struct gasket_interrupt_desc *interrupts;
++
++ /*
++ * If this device packs multiple interrupt->MSI-X mappings into a
++ * single register (i.e., "uses packed interrupts"), only a single bit
++ * width is supported for each interrupt mapping (unpacked/"full-width"
++ * interrupts are always supported). This value specifies that width. If
++ * packed interrupts are not used, this value is ignored.
++ */
++ int interrupt_pack_width;
++
++ /* Driver callback functions - all may be NULL */
++ /*
++ * device_open_cb: Callback for when a device node is opened in write
++ * mode.
++ * @dev: The gasket_dev struct for this driver instance.
++ *
++ * This callback should perform device-specific setup that needs to
++ * occur only once when a device is first opened.
++ */
++ int (*device_open_cb)(struct gasket_dev *dev);
++
++ /*
++ * device_release_cb: Callback when a device is closed.
++ * @gasket_dev: The gasket_dev struct for this driver instance.
++ *
++ * This callback is called whenever a device node fd is closed, as
++ * opposed to device_close_cb, which is called when the _last_
++ * descriptor for an open file is closed. This call is intended to
++ * handle any per-user or per-fd cleanup.
++ */
++ int (*device_release_cb)(struct gasket_dev *gasket_dev,
++ struct file *file);
++
++ /*
++ * device_close_cb: Callback for when a device node is closed for the
++ * last time.
++ * @dev: The gasket_dev struct for this driver instance.
++ *
++ * This callback should perform device-specific cleanup that only
++ * needs to occur when the last reference to a device node is closed.
++ *
++ * This call is intended to handle and device-wide cleanup, as opposed
++ * to per-fd cleanup (which should be handled by device_release_cb).
++ */
++ int (*device_close_cb)(struct gasket_dev *dev);
++
++ /*
++ * get_mappable_regions_cb: Get descriptors of mappable device memory.
++ * @gasket_dev: Pointer to the struct gasket_dev for this device.
++ * @bar_index: BAR for which to retrieve memory ranges.
++ * @mappable_regions: Out-pointer to the list of mappable regions on the
++ * device/BAR for this process.
++ * @num_mappable_regions: Out-pointer for the size of mappable_regions.
++ *
++ * Called when handling mmap(), this callback is used to determine which
++ * regions of device memory may be mapped by the current process. This
++ * information is then compared to mmap request to determine which
++ * regions to actually map.
++ */
++ int (*get_mappable_regions_cb)(struct gasket_dev *gasket_dev,
++ int bar_index,
++ struct gasket_mappable_region **mappable_regions,
++ int *num_mappable_regions);
++
++ /*
++ * ioctl_permissions_cb: Check permissions for generic ioctls.
++ * @filp: File structure pointer describing this node usage session.
++ * @cmd: ioctl number to handle.
++ * @arg: ioctl-specific data pointer.
++ *
++ * Returns 1 if the ioctl may be executed, 0 otherwise. If this callback
++ * isn't specified a default routine will be used, that only allows the
++ * original device opener (i.e, the "owner") to execute state-affecting
++ * ioctls.
++ */
++ gasket_ioctl_permissions_cb_t ioctl_permissions_cb;
++
++ /*
++ * ioctl_handler_cb: Callback to handle device-specific ioctls.
++ * @filp: File structure pointer describing this node usage session.
++ * @cmd: ioctl number to handle.
++ * @arg: ioctl-specific data pointer.
++ *
++ * Invoked whenever an ioctl is called that the generic Gasket
++ * framework doesn't support. If no cb is registered, unknown ioctls
++ * return -EINVAL. Should return an error status (either -EINVAL or
++ * the error result of the ioctl being handled).
++ */
++ gasket_ioctl_handler_cb_t ioctl_handler_cb;
++
++ /*
++ * device_status_cb: Callback to determine device health.
++ * @dev: Pointer to the gasket_dev struct for this device.
++ *
++ * Called to determine if the device is healthy or not. Should return
++ * a member of the gasket_status_type enum.
++ *
++ */
++ int (*device_status_cb)(struct gasket_dev *dev);
++
++ /*
++ * hardware_revision_cb: Get the device's hardware revision.
++ * @dev: Pointer to the gasket_dev struct for this device.
++ *
++ * Called to determine the reported rev of the physical hardware.
++ * Revision should be >0. A negative return value is an error.
++ */
++ int (*hardware_revision_cb)(struct gasket_dev *dev);
++
++ /*
++ * device_reset_cb: Reset the hardware in question.
++ * @dev: Pointer to the gasket_dev structure for this device.
++ *
++ * Called by reset ioctls. This function should not
++ * lock the gasket_dev mutex. It should return 0 on success
++ * and an error on failure.
++ */
++ int (*device_reset_cb)(struct gasket_dev *dev);
++};
++
++/*
++ * Register the specified device type with the framework.
++ * @desc: Populated/initialized device type descriptor.
++ *
++ * This function does _not_ take ownership of desc; the underlying struct must
++ * exist until the matching call to gasket_unregister_device.
++ * This function should be called from your driver's module_init function.
++ */
++int gasket_register_device(const struct gasket_driver_desc *desc);
++
++/*
++ * Remove the specified device type from the framework.
++ * @desc: Descriptor for the device type to unregister; it should have been
++ * passed to gasket_register_device in a previous call.
++ *
++ * This function should be called from your driver's module_exit function.
++ */
++void gasket_unregister_device(const struct gasket_driver_desc *desc);
++
++/* Add a PCI gasket device. */
++int gasket_pci_add_device(struct pci_dev *pci_dev,
++ struct gasket_dev **gasket_devp);
++/* Remove a PCI gasket device. */
++void gasket_pci_remove_device(struct pci_dev *pci_dev);
++
++/* Add a platform gasket device. */
++int gasket_platform_add_device(struct platform_device *pdev,
++ struct gasket_dev **gasket_devp);
++
++/* Remove a platform gasket device. */
++void gasket_platform_remove_device(struct platform_device *pdev);
++
++/* Set DMA device to use (if different from PCI/platform device) */
++void gasket_set_dma_device(struct gasket_dev *gasket_dev,
++ struct device *dma_dev);
++
++/* Enable a Gasket device. */
++int gasket_enable_device(struct gasket_dev *gasket_dev);
++
++/* Disable a Gasket device. */
++void gasket_disable_device(struct gasket_dev *gasket_dev);
++
++/*
++ * Reset the Gasket device.
++ * @gasket_dev: Gasket device struct.
++ *
++ * Calls device_reset_cb. Returns 0 on success and an error code othewrise.
++ * gasket_reset_nolock will not lock the mutex, gasket_reset will.
++ *
++ */
++int gasket_reset(struct gasket_dev *gasket_dev);
++int gasket_reset_nolock(struct gasket_dev *gasket_dev);
++
++/*
++ * Memory management functions. These will likely be spun off into their own
++ * file in the future.
++ */
++
++/* Unmaps the specified mappable region from a VMA. */
++int gasket_mm_unmap_region(const struct gasket_dev *gasket_dev,
++ struct vm_area_struct *vma,
++ const struct gasket_mappable_region *map_region);
++
++/*
++ * Get the ioctl permissions callback.
++ * @gasket_dev: Gasket device structure.
++ */
++gasket_ioctl_permissions_cb_t
++gasket_get_ioctl_permissions_cb(struct gasket_dev *gasket_dev);
++
++/**
++ * Lookup a name by number in a num_name table.
++ * @num: Number to lookup.
++ * @table: Array of num_name structures, the table for the lookup.
++ *
++ */
++const char *gasket_num_name_lookup(uint num,
++ const struct gasket_num_name *table);
++
++/* Handy inlines */
++static inline u64 gasket_dev_read_64(struct gasket_dev *gasket_dev, int bar,
++ ulong location)
++{
++ return readq_relaxed(&gasket_dev->bar_data[bar].virt_base[location]);
++}
++
++static inline void gasket_dev_write_64(struct gasket_dev *dev, u64 value,
++ int bar, ulong location)
++{
++ writeq_relaxed(value, &dev->bar_data[bar].virt_base[location]);
++}
++
++static inline void gasket_dev_write_32(struct gasket_dev *dev, u32 value,
++ int bar, ulong location)
++{
++ writel_relaxed(value, &dev->bar_data[bar].virt_base[location]);
++}
++
++static inline u32 gasket_dev_read_32(struct gasket_dev *dev, int bar,
++ ulong location)
++{
++ return readl_relaxed(&dev->bar_data[bar].virt_base[location]);
++}
++
++static inline void gasket_read_modify_write_64(struct gasket_dev *dev, int bar,
++ ulong location, u64 value,
++ u64 mask_width, u64 mask_shift)
++{
++ u64 mask, tmp;
++
++ tmp = gasket_dev_read_64(dev, bar, location);
++ mask = ((1ULL << mask_width) - 1) << mask_shift;
++ tmp = (tmp & ~mask) | (value << mask_shift);
++ gasket_dev_write_64(dev, tmp, bar, location);
++}
++
++static inline void gasket_read_modify_write_32(struct gasket_dev *dev, int bar,
++ ulong location, u32 value,
++ u32 mask_width, u32 mask_shift)
++{
++ u32 mask, tmp;
++
++ tmp = gasket_dev_read_32(dev, bar, location);
++ mask = ((1 << mask_width) - 1) << mask_shift;
++ tmp = (tmp & ~mask) | (value << mask_shift);
++ gasket_dev_write_32(dev, tmp, bar, location);
++}
++
++/* Get the Gasket driver structure for a given device. */
++const struct gasket_driver_desc *gasket_get_driver_desc(struct gasket_dev *dev);
++
++/* Get the device structure for a given device. */
++struct device *gasket_get_device(struct gasket_dev *dev);
++
++/* Helper function, Asynchronous waits on a given set of bits. */
++int gasket_wait_with_reschedule(struct gasket_dev *gasket_dev, int bar,
++ u64 offset, u64 mask, u64 val,
++ uint max_retries, u64 delay_ms);
++
++#endif /* __GASKET_CORE_H__ */
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket.h b/drivers/staging/gasket-driver/gasket.h
+--- a/drivers/staging/gasket-driver/gasket.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,177 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/*
++ * Common Gasket device kernel and user space declarations.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++#ifndef __GASKET_H__
++#define __GASKET_H__
++
++#include <linux/ioctl.h>
++#include <linux/types.h>
++
++/* ioctl structure declarations */
++
++/* Ioctl structures are padded to a multiple of 64 bits */
++/* and padded to put 64 bit values on 64 bit boundaries. */
++/* Unsigned 64 bit integers are used to hold pointers. */
++/* This helps compatibility between 32 and 64 bits. */
++
++/*
++ * Common structure for ioctls associating an eventfd with a device interrupt,
++ * when using the Gasket interrupt module.
++ */
++struct gasket_interrupt_eventfd {
++ u64 interrupt;
++ u64 event_fd;
++};
++
++/*
++ * Common structure for ioctls mapping and unmapping buffers when using the
++ * Gasket page_table module.
++ */
++struct gasket_page_table_ioctl {
++ u64 page_table_index;
++ u64 size;
++ u64 host_address;
++ u64 device_address;
++};
++
++/*
++ * Structure for ioctl mapping buffers with flags when using the Gasket
++ * page_table module.
++ */
++struct gasket_page_table_ioctl_flags {
++ struct gasket_page_table_ioctl base;
++ /*
++ * Flags indicating status and attribute requests from the host.
++ * NOTE: STATUS bit does not need to be set in this request.
++ * Set RESERVED bits to 0 to ensure backwards compatibility.
++ *
++ * Bitfields:
++ * [0] - STATUS: indicates if this entry/slot is free
++ * 0 = PTE_FREE
++ * 1 = PTE_INUSE
++ * [2:1] - DMA_DIRECTION: dma_data_direction requested by host
++ * 00 = DMA_BIDIRECTIONAL
++ * 01 = DMA_TO_DEVICE
++ * 10 = DMA_FROM_DEVICE
++ * 11 = DMA_NONE
++ * [31:3] - RESERVED
++ */
++ u32 flags;
++};
++
++/*
++ * Common structure for ioctls mapping and unmapping buffers when using the
++ * Gasket page_table module.
++ * dma_address: phys addr start of coherent memory, allocated by kernel
++ */
++struct gasket_coherent_alloc_config_ioctl {
++ u64 page_table_index;
++ u64 enable;
++ u64 size;
++ u64 dma_address;
++};
++
++/*
++ * Common structure for ioctls mapping and unmapping dma-bufs when using the
++ * Gasket page_table module.
++ * map: boolean, non-zero to map, 0 to unmap.
++ * flags: see gasket_page_table_ioctl_flags.flags.
++ */
++struct gasket_page_table_ioctl_dmabuf {
++ u64 page_table_index;
++ u64 device_address;
++ int dmabuf_fd;
++ u32 num_pages;
++ u32 map;
++ u32 flags;
++};
++
++/* Base number for all Gasket-common IOCTLs */
++#define GASKET_IOCTL_BASE 0xDC
++
++/* Reset the device. */
++#define GASKET_IOCTL_RESET _IO(GASKET_IOCTL_BASE, 0)
++
++/* Associate the specified [event]fd with the specified interrupt. */
++#define GASKET_IOCTL_SET_EVENTFD \
++ _IOW(GASKET_IOCTL_BASE, 1, struct gasket_interrupt_eventfd)
++
++/*
++ * Clears any eventfd associated with the specified interrupt. The (ulong)
++ * argument is the interrupt number to clear.
++ */
++#define GASKET_IOCTL_CLEAR_EVENTFD _IOW(GASKET_IOCTL_BASE, 2, unsigned long)
++
++/*
++ * [Loopbacks only] Requests that the loopback device send the specified
++ * interrupt to the host. The (ulong) argument is the number of the interrupt to
++ * send.
++ */
++#define GASKET_IOCTL_LOOPBACK_INTERRUPT \
++ _IOW(GASKET_IOCTL_BASE, 3, unsigned long)
++
++/* Queries the kernel for the number of page tables supported by the device. */
++#define GASKET_IOCTL_NUMBER_PAGE_TABLES _IOR(GASKET_IOCTL_BASE, 4, u64)
++
++/*
++ * Queries the kernel for the maximum size of the page table. Only the size and
++ * page_table_index fields are used from the struct gasket_page_table_ioctl.
++ */
++#define GASKET_IOCTL_PAGE_TABLE_SIZE \
++ _IOWR(GASKET_IOCTL_BASE, 5, struct gasket_page_table_ioctl)
++
++/*
++ * Queries the kernel for the current simple page table size. Only the size and
++ * page_table_index fields are used from the struct gasket_page_table_ioctl.
++ */
++#define GASKET_IOCTL_SIMPLE_PAGE_TABLE_SIZE \
++ _IOWR(GASKET_IOCTL_BASE, 6, struct gasket_page_table_ioctl)
++
++/*
++ * Tells the kernel to change the split between the number of simple and
++ * extended entries in the given page table. Only the size and page_table_index
++ * fields are used from the struct gasket_page_table_ioctl.
++ */
++#define GASKET_IOCTL_PARTITION_PAGE_TABLE \
++ _IOW(GASKET_IOCTL_BASE, 7, struct gasket_page_table_ioctl)
++
++/*
++ * Tells the kernel to map size bytes at host_address to device_address in
++ * page_table_index page table.
++ */
++#define GASKET_IOCTL_MAP_BUFFER \
++ _IOW(GASKET_IOCTL_BASE, 8, struct gasket_page_table_ioctl)
++
++/*
++ * Tells the kernel to unmap size bytes at host_address from device_address in
++ * page_table_index page table.
++ */
++#define GASKET_IOCTL_UNMAP_BUFFER \
++ _IOW(GASKET_IOCTL_BASE, 9, struct gasket_page_table_ioctl)
++
++/* Clear the interrupt counts stored for this device. */
++#define GASKET_IOCTL_CLEAR_INTERRUPT_COUNTS _IO(GASKET_IOCTL_BASE, 10)
++
++/* Enable/Disable and configure the coherent allocator. */
++#define GASKET_IOCTL_CONFIG_COHERENT_ALLOCATOR \
++ _IOWR(GASKET_IOCTL_BASE, 11, struct gasket_coherent_alloc_config_ioctl)
++
++/*
++ * Tells the kernel to map size bytes at host_address to device_address in
++ * page_table_index page table. Passes flags to indicate additional attribute
++ * requests for the mapped memory.
++ */
++#define GASKET_IOCTL_MAP_BUFFER_FLAGS \
++ _IOW(GASKET_IOCTL_BASE, 12, struct gasket_page_table_ioctl_flags)
++
++/*
++ * Tells the kernel to map/unmap dma-buf with fd to device_address in
++ * page_table_index page table.
++ */
++#define GASKET_IOCTL_MAP_DMABUF \
++ _IOW(GASKET_IOCTL_BASE, 13, struct gasket_page_table_ioctl_dmabuf)
++
++#endif /* __GASKET_H__ */
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_interrupt.c b/drivers/staging/gasket-driver/gasket_interrupt.c
+--- a/drivers/staging/gasket-driver/gasket_interrupt.c 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_interrupt.c 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,559 @@
++// SPDX-License-Identifier: GPL-2.0
++/* Copyright (C) 2018 Google, Inc. */
++
++#include "gasket_interrupt.h"
++
++#include "gasket_constants.h"
++#include "gasket_core.h"
++#include "gasket_sysfs.h"
++#include <linux/device.h>
++#include <linux/interrupt.h>
++#include <linux/printk.h>
++#include <linux/spinlock.h>
++#include <linux/version.h>
++#ifdef GASKET_KERNEL_TRACE_SUPPORT
++#define CREATE_TRACE_POINTS
++#include <trace/events/gasket_interrupt.h>
++#else
++#define trace_gasket_interrupt_event(x, ...)
++#endif
++/* Retry attempts if the requested number of interrupts aren't available. */
++#define MSIX_RETRY_COUNT 3
++
++/* Instance interrupt management data. */
++struct gasket_interrupt_data {
++ /* The name associated with this interrupt data. */
++ const char *name;
++
++ /* Interrupt type. See gasket_interrupt_type in gasket_core.h */
++ int type;
++
++ /* The PCI device [if any] associated with the owning device. */
++ struct pci_dev *pci_dev;
++
++ /* Set to 1 if MSI-X has successfully been configred, 0 otherwise. */
++ int msix_configured;
++
++ /* The number of interrupts requested by the owning device. */
++ int num_interrupts;
++
++ /* A pointer to the interrupt descriptor struct for this device. */
++ const struct gasket_interrupt_desc *interrupts;
++
++ /* The index of the bar into which interrupts should be mapped. */
++ int interrupt_bar_index;
++
++ /* The width of a single interrupt in a packed interrupt register. */
++ int pack_width;
++
++ /*
++ * Design-wise, these elements should be bundled together, but
++ * pci_enable_msix's interface requires that they be managed
++ * individually (requires array of struct msix_entry).
++ */
++
++ /* The number of successfully configured interrupts. */
++ int num_configured;
++
++ /* The MSI-X data for each requested/configured interrupt. */
++ struct msix_entry *msix_entries;
++
++ /* The eventfd "callback" data for each interrupt. */
++ struct eventfd_ctx **eventfd_ctxs;
++
++ /* Spinlock to protect read/write races to eventfd_ctxs. */
++ rwlock_t eventfd_ctx_lock;
++
++ /* The number of times each interrupt has been called. */
++ ulong *interrupt_counts;
++
++ /* Linux IRQ number. */
++ int irq;
++};
++
++/* Structures to display interrupt counts in sysfs. */
++enum interrupt_sysfs_attribute_type {
++ ATTR_INTERRUPT_COUNTS,
++};
++
++/* Set up device registers for interrupt handling. */
++static void gasket_interrupt_setup(struct gasket_dev *gasket_dev)
++{
++ int i;
++ int pack_shift;
++ u64 mask;
++ u64 value;
++ struct gasket_interrupt_data *interrupt_data =
++ gasket_dev->interrupt_data;
++
++ if (!interrupt_data) {
++ dev_dbg(gasket_dev->dev, "Interrupt data is not initialized\n");
++ return;
++ }
++
++ dev_dbg(gasket_dev->dev, "Running interrupt setup\n");
++
++ if (interrupt_data->type == DEVICE_MANAGED)
++ return; /* device driver handles setup */
++
++ /* Setup the MSIX table. */
++
++ for (i = 0; i < interrupt_data->num_interrupts; i++) {
++ /*
++ * If the interrupt is not packed, we can write the index into
++ * the register directly. If not, we need to deal with a read-
++ * modify-write and shift based on the packing index.
++ */
++ dev_dbg(gasket_dev->dev,
++ "Setting up interrupt index %d with index 0x%llx and "
++ "packing %d\n",
++ interrupt_data->interrupts[i].index,
++ interrupt_data->interrupts[i].reg,
++ interrupt_data->interrupts[i].packing);
++ if (interrupt_data->interrupts[i].packing == UNPACKED) {
++ value = interrupt_data->interrupts[i].index;
++ } else {
++ switch (interrupt_data->interrupts[i].packing) {
++ case PACK_0:
++ pack_shift = 0;
++ break;
++ case PACK_1:
++ pack_shift = interrupt_data->pack_width;
++ break;
++ case PACK_2:
++ pack_shift = 2 * interrupt_data->pack_width;
++ break;
++ case PACK_3:
++ pack_shift = 3 * interrupt_data->pack_width;
++ break;
++ default:
++ dev_dbg(gasket_dev->dev,
++ "Found interrupt description with "
++ "unknown enum %d\n",
++ interrupt_data->interrupts[i].packing);
++ return;
++ }
++
++ mask = ~(0xFFFF << pack_shift);
++ value = gasket_dev_read_64(gasket_dev,
++ interrupt_data->interrupt_bar_index,
++ interrupt_data->interrupts[i].reg);
++ value &= mask;
++ value |= interrupt_data->interrupts[i].index
++ << pack_shift;
++ }
++ gasket_dev_write_64(gasket_dev, value,
++ interrupt_data->interrupt_bar_index,
++ interrupt_data->interrupts[i].reg);
++ }
++}
++
++void
++gasket_handle_interrupt(struct gasket_interrupt_data *interrupt_data,
++ int interrupt_index)
++{
++ struct eventfd_ctx *ctx;
++
++ trace_gasket_interrupt_event(interrupt_data->name, interrupt_index);
++ read_lock(&interrupt_data->eventfd_ctx_lock);
++ ctx = interrupt_data->eventfd_ctxs[interrupt_index];
++ if (ctx)
++ #if LINUX_VERSION_CODE >= KERNEL_VERSION(6,8,0)
++ eventfd_signal(ctx);
++ #else
++ eventfd_signal(ctx, 1);
++ #endif
++ read_unlock(&interrupt_data->eventfd_ctx_lock);
++
++ ++(interrupt_data->interrupt_counts[interrupt_index]);
++}
++
++static irqreturn_t gasket_msix_interrupt_handler(int irq, void *dev_id)
++{
++ struct gasket_interrupt_data *interrupt_data = dev_id;
++ int interrupt = -1;
++ int i;
++
++ /* If this linear lookup is a problem, we can maintain a map/hash. */
++ for (i = 0; i < interrupt_data->num_interrupts; i++) {
++ if (interrupt_data->msix_entries[i].vector == irq) {
++ interrupt = interrupt_data->msix_entries[i].entry;
++ break;
++ }
++ }
++ if (interrupt == -1) {
++ pr_err("Received unknown irq %d\n", irq);
++ return IRQ_HANDLED;
++ }
++ gasket_handle_interrupt(interrupt_data, interrupt);
++ return IRQ_HANDLED;
++}
++
++static int
++gasket_interrupt_msix_init(struct gasket_interrupt_data *interrupt_data)
++{
++ int ret = 1;
++ int i;
++
++ interrupt_data->msix_entries =
++ kcalloc(interrupt_data->num_interrupts,
++ sizeof(struct msix_entry), GFP_KERNEL);
++ if (!interrupt_data->msix_entries)
++ return -ENOMEM;
++
++ for (i = 0; i < interrupt_data->num_interrupts; i++) {
++ interrupt_data->msix_entries[i].entry = i;
++ interrupt_data->msix_entries[i].vector = 0;
++ interrupt_data->eventfd_ctxs[i] = NULL;
++ }
++
++ /* Retry MSIX_RETRY_COUNT times if not enough IRQs are available. */
++ for (i = 0; i < MSIX_RETRY_COUNT && ret > 0; i++)
++ ret = pci_enable_msix_exact(interrupt_data->pci_dev,
++ interrupt_data->msix_entries,
++ interrupt_data->num_interrupts);
++
++ if (ret)
++ return ret > 0 ? -EBUSY : ret;
++ interrupt_data->msix_configured = 1;
++
++ for (i = 0; i < interrupt_data->num_interrupts; i++) {
++ ret = request_irq(interrupt_data->msix_entries[i].vector,
++ gasket_msix_interrupt_handler, 0,
++ interrupt_data->name, interrupt_data);
++
++ if (ret) {
++ dev_err(&interrupt_data->pci_dev->dev,
++ "Cannot get IRQ for interrupt %d, vector %d; "
++ "%d\n",
++ i, interrupt_data->msix_entries[i].vector, ret);
++ return ret;
++ }
++
++ interrupt_data->num_configured++;
++ }
++
++ return 0;
++}
++
++/*
++ * On QCM DragonBoard, we exit gasket_interrupt_msix_init() and kernel interrupt
++ * setup code with MSIX vectors masked. This is wrong because nothing else in
++ * the driver will normally touch the MSIX vectors.
++ *
++ * As a temporary hack, force unmasking there.
++ *
++ * TODO: Figure out why QCM kernel doesn't unmask the MSIX vectors, after
++ * gasket_interrupt_msix_init(), and remove this code.
++ */
++static void force_msix_interrupt_unmasking(struct gasket_dev *gasket_dev)
++{
++ int i;
++#define MSIX_VECTOR_SIZE 16
++#define MSIX_MASK_BIT_OFFSET 12
++#define APEX_BAR2_REG_KERNEL_HIB_MSIX_TABLE 0x46800
++ for (i = 0; i < gasket_dev->interrupt_data->num_configured; i++) {
++ /* Check if the MSIX vector is unmasked */
++ ulong location = APEX_BAR2_REG_KERNEL_HIB_MSIX_TABLE +
++ MSIX_MASK_BIT_OFFSET + i * MSIX_VECTOR_SIZE;
++ u32 mask =
++ gasket_dev_read_32(gasket_dev,
++ gasket_dev->interrupt_data->interrupt_bar_index,
++ location);
++ if (!(mask & 1))
++ continue;
++ /* Unmask the msix vector (clear 32 bits) */
++ gasket_dev_write_32(gasket_dev, 0,
++ gasket_dev->interrupt_data->interrupt_bar_index,
++ location);
++ }
++#undef MSIX_VECTOR_SIZE
++#undef MSIX_MASK_BIT_OFFSET
++#undef APEX_BAR2_REG_KERNEL_HIB_MSIX_TABLE
++}
++
++static ssize_t interrupt_sysfs_show(struct device *device,
++ struct device_attribute *attr, char *buf)
++{
++ int i, ret;
++ ssize_t written = 0, total_written = 0;
++ struct gasket_interrupt_data *interrupt_data;
++ struct gasket_dev *gasket_dev;
++ struct gasket_sysfs_attribute *gasket_attr;
++ enum interrupt_sysfs_attribute_type sysfs_type;
++
++ gasket_dev = gasket_sysfs_get_device_data(device);
++ if (!gasket_dev) {
++ dev_dbg(device, "No sysfs mapping found for device\n");
++ return 0;
++ }
++
++ gasket_attr = gasket_sysfs_get_attr(device, attr);
++ if (!gasket_attr) {
++ dev_dbg(device, "No sysfs attr data found for device\n");
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return 0;
++ }
++
++ sysfs_type = (enum interrupt_sysfs_attribute_type)
++ gasket_attr->data.attr_type;
++ interrupt_data = gasket_dev->interrupt_data;
++ switch (sysfs_type) {
++ case ATTR_INTERRUPT_COUNTS:
++ for (i = 0; i < interrupt_data->num_interrupts; ++i) {
++ written =
++ scnprintf(buf, PAGE_SIZE - total_written,
++ "0x%02x: %ld\n", i,
++ interrupt_data->interrupt_counts[i]);
++ total_written += written;
++ buf += written;
++ }
++ ret = total_written;
++ break;
++ default:
++ dev_dbg(gasket_dev->dev, "Unknown attribute: %s\n",
++ attr->attr.name);
++ ret = 0;
++ break;
++ }
++
++ gasket_sysfs_put_attr(device, gasket_attr);
++ gasket_sysfs_put_device_data(device, gasket_dev);
++ return ret;
++}
++
++static struct gasket_sysfs_attribute interrupt_sysfs_attrs[] = {
++ GASKET_SYSFS_RO(interrupt_counts, interrupt_sysfs_show,
++ ATTR_INTERRUPT_COUNTS),
++ GASKET_END_OF_ATTR_ARRAY,
++};
++
++int gasket_interrupt_init(struct gasket_dev *gasket_dev)
++{
++ int ret;
++ struct gasket_interrupt_data *interrupt_data;
++ const struct gasket_driver_desc *driver_desc =
++ gasket_get_driver_desc(gasket_dev);
++
++ interrupt_data = kzalloc(sizeof(struct gasket_interrupt_data),
++ GFP_KERNEL);
++ if (!interrupt_data)
++ return -ENOMEM;
++ gasket_dev->interrupt_data = interrupt_data;
++ interrupt_data->name = driver_desc->name;
++ interrupt_data->type = driver_desc->interrupt_type;
++ interrupt_data->pci_dev = gasket_dev->pci_dev;
++ interrupt_data->num_interrupts = driver_desc->num_interrupts;
++ interrupt_data->interrupts = driver_desc->interrupts;
++ interrupt_data->interrupt_bar_index = driver_desc->interrupt_bar_index;
++ interrupt_data->pack_width = driver_desc->interrupt_pack_width;
++
++ interrupt_data->eventfd_ctxs = kcalloc(driver_desc->num_interrupts,
++ sizeof(struct eventfd_ctx *),
++ GFP_KERNEL);
++ if (!interrupt_data->eventfd_ctxs) {
++ kfree(interrupt_data);
++ return -ENOMEM;
++ }
++
++ interrupt_data->interrupt_counts = kcalloc(driver_desc->num_interrupts,
++ sizeof(ulong),
++ GFP_KERNEL);
++ if (!interrupt_data->interrupt_counts) {
++ kfree(interrupt_data->eventfd_ctxs);
++ kfree(interrupt_data);
++ return -ENOMEM;
++ }
++
++ rwlock_init(&interrupt_data->eventfd_ctx_lock);
++
++ switch (interrupt_data->type) {
++ case PCI_MSIX:
++ ret = gasket_interrupt_msix_init(interrupt_data);
++ if (ret)
++ break;
++ force_msix_interrupt_unmasking(gasket_dev);
++ break;
++
++ case DEVICE_MANAGED: /* Device driver manages IRQ init */
++ interrupt_data->num_configured = interrupt_data->num_interrupts;
++ ret = 0;
++ break;
++
++ default:
++ ret = -EINVAL;
++ }
++
++ if (ret) {
++ /* Failing to setup interrupts will cause the device to report
++ * GASKET_STATUS_LAMED. But it is not fatal.
++ */
++ dev_warn(gasket_dev->dev,
++ "Couldn't initialize interrupts: %d\n", ret);
++ return 0;
++ }
++
++ gasket_interrupt_setup(gasket_dev);
++ gasket_sysfs_create_entries(gasket_dev->dev_info.device,
++ interrupt_sysfs_attrs);
++
++ return 0;
++}
++EXPORT_SYMBOL(gasket_interrupt_init);
++
++void gasket_interrupt_msix_cleanup(struct gasket_interrupt_data *interrupt_data)
++{
++ int i;
++
++ for (i = 0; i < interrupt_data->num_configured; i++) {
++ gasket_interrupt_clear_eventfd(interrupt_data, i);
++ free_irq(interrupt_data->msix_entries[i].vector,
++ interrupt_data);
++ }
++ interrupt_data->num_configured = 0;
++
++ if (interrupt_data->msix_configured)
++ pci_disable_msix(interrupt_data->pci_dev);
++ interrupt_data->msix_configured = 0;
++ kfree(interrupt_data->msix_entries);
++ interrupt_data->msix_entries = NULL;
++}
++EXPORT_SYMBOL(gasket_interrupt_msix_cleanup);
++
++int gasket_interrupt_reinit(struct gasket_dev *gasket_dev)
++{
++ int ret;
++
++ if (!gasket_dev->interrupt_data) {
++ dev_dbg(gasket_dev->dev,
++ "Attempted to reinit uninitialized interrupt data\n");
++ return -EINVAL;
++ }
++
++ switch (gasket_dev->interrupt_data->type) {
++ case PCI_MSIX:
++ gasket_interrupt_msix_cleanup(gasket_dev->interrupt_data);
++ ret = gasket_interrupt_msix_init(gasket_dev->interrupt_data);
++ if (ret)
++ break;
++ force_msix_interrupt_unmasking(gasket_dev);
++ break;
++
++ case DEVICE_MANAGED: /* Device driver manages IRQ reinit */
++ ret = 0;
++ break;
++
++ default:
++ ret = -EINVAL;
++ }
++
++ if (ret) {
++ /* Failing to setup interrupts will cause the device
++ * to report GASKET_STATUS_LAMED, but is not fatal.
++ */
++ dev_warn(gasket_dev->dev, "Couldn't reinit interrupts: %d\n",
++ ret);
++ return 0;
++ }
++
++ gasket_interrupt_setup(gasket_dev);
++
++ return 0;
++}
++EXPORT_SYMBOL(gasket_interrupt_reinit);
++
++/* See gasket_interrupt.h for description. */
++int gasket_interrupt_reset_counts(struct gasket_dev *gasket_dev)
++{
++ dev_dbg(gasket_dev->dev, "Clearing interrupt counts\n");
++ memset(gasket_dev->interrupt_data->interrupt_counts, 0,
++ gasket_dev->interrupt_data->num_interrupts *
++ sizeof(*gasket_dev->interrupt_data->interrupt_counts));
++ return 0;
++}
++
++/* See gasket_interrupt.h for description. */
++void gasket_interrupt_cleanup(struct gasket_dev *gasket_dev)
++{
++ struct gasket_interrupt_data *interrupt_data =
++ gasket_dev->interrupt_data;
++ /*
++ * It is possible to get an error code from gasket_interrupt_init
++ * before interrupt_data has been allocated, so check it.
++ */
++ if (!interrupt_data)
++ return;
++
++ switch (interrupt_data->type) {
++ case PCI_MSIX:
++ gasket_interrupt_msix_cleanup(interrupt_data);
++ break;
++
++ case DEVICE_MANAGED: /* Device driver manages IRQ cleanup */
++ break;
++
++ default:
++ break;
++ }
++
++ kfree(interrupt_data->interrupt_counts);
++ kfree(interrupt_data->eventfd_ctxs);
++ kfree(interrupt_data);
++ gasket_dev->interrupt_data = NULL;
++}
++
++int gasket_interrupt_system_status(struct gasket_dev *gasket_dev)
++{
++ if (!gasket_dev->interrupt_data) {
++ dev_dbg(gasket_dev->dev, "Interrupt data is null\n");
++ return GASKET_STATUS_DEAD;
++ }
++
++ if (gasket_dev->interrupt_data->num_configured !=
++ gasket_dev->interrupt_data->num_interrupts) {
++ dev_dbg(gasket_dev->dev,
++ "Not all interrupts were configured\n");
++ return GASKET_STATUS_LAMED;
++ }
++
++ return GASKET_STATUS_ALIVE;
++}
++
++int gasket_interrupt_set_eventfd(struct gasket_interrupt_data *interrupt_data,
++ int interrupt, int event_fd)
++{
++ struct eventfd_ctx *ctx;
++ ulong flags;
++
++ if (interrupt < 0 || interrupt >= interrupt_data->num_interrupts)
++ return -EINVAL;
++
++ ctx = eventfd_ctx_fdget(event_fd);
++ if (IS_ERR(ctx))
++ return PTR_ERR(ctx);
++
++ /* Put the old eventfd ctx before setting, else we leak the ref. */
++ write_lock_irqsave(&interrupt_data->eventfd_ctx_lock, flags);
++ if (interrupt_data->eventfd_ctxs[interrupt] != NULL)
++ eventfd_ctx_put(interrupt_data->eventfd_ctxs[interrupt]);
++ interrupt_data->eventfd_ctxs[interrupt] = ctx;
++ write_unlock_irqrestore(&interrupt_data->eventfd_ctx_lock, flags);
++ return 0;
++}
++
++int gasket_interrupt_clear_eventfd(struct gasket_interrupt_data *interrupt_data,
++ int interrupt)
++{
++ ulong flags;
++
++ if (interrupt < 0 || interrupt >= interrupt_data->num_interrupts)
++ return -EINVAL;
++
++ /* Put the old eventfd ctx before clearing, else we leak the ref. */
++ write_lock_irqsave(&interrupt_data->eventfd_ctx_lock, flags);
++ if (interrupt_data->eventfd_ctxs[interrupt] != NULL)
++ eventfd_ctx_put(interrupt_data->eventfd_ctxs[interrupt]);
++ interrupt_data->eventfd_ctxs[interrupt] = NULL;
++ write_unlock_irqrestore(&interrupt_data->eventfd_ctx_lock, flags);
++ return 0;
++}
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_interrupt.h b/drivers/staging/gasket-driver/gasket_interrupt.h
+--- a/drivers/staging/gasket-driver/gasket_interrupt.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_interrupt.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,108 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/*
++ * Gasket common interrupt module. Defines functions for enabling
++ * eventfd-triggered interrupts between a Gasket device and a host process.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++#ifndef __GASKET_INTERRUPT_H__
++#define __GASKET_INTERRUPT_H__
++
++#include <linux/eventfd.h>
++#include <linux/pci.h>
++
++#include "gasket_core.h"
++
++/* Note that this currently assumes that device interrupts are a dense set,
++ * numbered from 0 - (num_interrupts - 1). Should this have to change, these
++ * APIs will have to be updated.
++ */
++
++/* Opaque type used to hold interrupt subsystem data. */
++struct gasket_interrupt_data;
++
++/*
++ * Initialize the interrupt module.
++ * @gasket_dev: The Gasket device structure for the device to be initted.
++ */
++int gasket_interrupt_init(struct gasket_dev *gasket_dev);
++
++/*
++ * Clean up a device's interrupt structure.
++ * @gasket_dev: The Gasket information structure for this device.
++ *
++ * Cleans up the device's interrupts and deallocates data.
++ */
++void gasket_interrupt_cleanup(struct gasket_dev *gasket_dev);
++
++/*
++ * Clean up and re-initialize the MSI-x subsystem.
++ * @gasket_dev: The Gasket information structure for this device.
++ *
++ * Performs a teardown of the MSI-x subsystem and re-initializes it. Does not
++ * free the underlying data structures. Returns 0 on success and an error code
++ * on error.
++ */
++int gasket_interrupt_reinit(struct gasket_dev *gasket_dev);
++
++/*
++ * Clean up the MSI-x subsystem.
++ * @interrupt_data: The interrupt data structure for this device.
++ *
++ * Performs a teardown of the MSI-x subsystem. Does not free the underlying data structures.
++ */
++void gasket_interrupt_msix_cleanup(struct gasket_interrupt_data *interrupt_data);
++
++/* Handle gasket interrupt processing, called from an external handler. */
++void
++gasket_handle_interrupt(struct gasket_interrupt_data *interrupt_data,
++ int interrupt_index);
++
++/*
++ * Reset the counts stored in the interrupt subsystem.
++ * @gasket_dev: The Gasket information structure for this device.
++ *
++ * Sets the counts of all interrupts in the subsystem to 0.
++ */
++int gasket_interrupt_reset_counts(struct gasket_dev *gasket_dev);
++
++/*
++ * Associates an eventfd with a device interrupt.
++ * @data: Pointer to device interrupt data.
++ * @interrupt: The device interrupt to configure.
++ * @event_fd: The eventfd to associate with the interrupt.
++ *
++ * Prepares the host to receive notification of device interrupts by associating
++ * event_fd with interrupt. Upon receipt of a device interrupt, event_fd will be
++ * signaled, after successful configuration.
++ *
++ * Returns 0 on success, a negative error code otherwise.
++ */
++int gasket_interrupt_set_eventfd(struct gasket_interrupt_data *interrupt_data,
++ int interrupt, int event_fd);
++
++/*
++ * Removes an interrupt-eventfd association.
++ * @data: Pointer to device interrupt data.
++ * @interrupt: The device interrupt to de-associate.
++ *
++ * Removes any eventfd associated with the specified interrupt, if any.
++ */
++int gasket_interrupt_clear_eventfd(struct gasket_interrupt_data *interrupt_data,
++ int interrupt);
++
++/*
++ * The below functions exist for backwards compatibility.
++ * No new uses should be written.
++ */
++/*
++ * Get the health of the interrupt subsystem.
++ * @gasket_dev: The Gasket device struct.
++ *
++ * Returns DEAD if not set up, LAMED if initialization failed, and ALIVE
++ * otherwise.
++ */
++
++int gasket_interrupt_system_status(struct gasket_dev *gasket_dev);
++
++#endif
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_ioctl.c b/drivers/staging/gasket-driver/gasket_ioctl.c
+--- a/drivers/staging/gasket-driver/gasket_ioctl.c 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_ioctl.c 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,470 @@
++// SPDX-License-Identifier: GPL-2.0
++/* Copyright (C) 2018 Google, Inc. */
++#include "gasket.h"
++#include "gasket_ioctl.h"
++#include "gasket_constants.h"
++#include "gasket_core.h"
++#include "gasket_interrupt.h"
++#include "gasket_page_table.h"
++#include <linux/compiler.h>
++#include <linux/device.h>
++#include <linux/fs.h>
++#include <linux/uaccess.h>
++
++#ifdef GASKET_KERNEL_TRACE_SUPPORT
++#define CREATE_TRACE_POINTS
++#include <trace/events/gasket_ioctl.h>
++#else
++#define trace_gasket_ioctl_entry(x, ...)
++#define trace_gasket_ioctl_exit(x)
++#define trace_gasket_ioctl_integer_data(x)
++#define trace_gasket_ioctl_eventfd_data(x, ...)
++#define trace_gasket_ioctl_page_table_data(x, ...)
++#define trace_gasket_ioctl_page_table_flags_data(x, ...)
++#define trace_gasket_ioctl_config_coherent_allocator(x, ...)
++#endif
++
++/* Associate an eventfd with an interrupt. */
++static int gasket_set_event_fd(struct gasket_dev *gasket_dev,
++ struct gasket_interrupt_eventfd __user *argp)
++{
++ struct gasket_interrupt_eventfd die;
++
++ if (copy_from_user(&die, argp, sizeof(struct gasket_interrupt_eventfd)))
++ return -EFAULT;
++
++ trace_gasket_ioctl_eventfd_data(die.interrupt, die.event_fd);
++
++ return gasket_interrupt_set_eventfd(
++ gasket_dev->interrupt_data, die.interrupt, die.event_fd);
++}
++
++/* Read the size of the page table. */
++static int gasket_read_page_table_size(
++ struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl __user *argp)
++{
++ int ret = 0;
++ struct gasket_page_table_ioctl ibuf;
++
++ if (copy_from_user(&ibuf, argp, sizeof(struct gasket_page_table_ioctl)))
++ return -EFAULT;
++
++ if (ibuf.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++
++ ibuf.size = gasket_page_table_num_entries(
++ gasket_dev->page_table[ibuf.page_table_index]);
++
++ trace_gasket_ioctl_page_table_data(
++ ibuf.page_table_index, ibuf.size, ibuf.host_address,
++ ibuf.device_address);
++
++ if (copy_to_user(argp, &ibuf, sizeof(ibuf)))
++ return -EFAULT;
++
++ return ret;
++}
++
++/* Read the size of the simple page table. */
++static int gasket_read_simple_page_table_size(
++ struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl __user *argp)
++{
++ int ret = 0;
++ struct gasket_page_table_ioctl ibuf;
++
++ if (copy_from_user(&ibuf, argp, sizeof(struct gasket_page_table_ioctl)))
++ return -EFAULT;
++
++ if (ibuf.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++
++ ibuf.size =
++ gasket_page_table_num_simple_entries(gasket_dev->page_table[ibuf.page_table_index]);
++
++ trace_gasket_ioctl_page_table_data(ibuf.page_table_index, ibuf.size,
++ ibuf.host_address,
++ ibuf.device_address);
++
++ if (copy_to_user(argp, &ibuf, sizeof(ibuf)))
++ return -EFAULT;
++
++ return ret;
++}
++
++/* Set the boundary between the simple and extended page tables. */
++static int gasket_partition_page_table(
++ struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl __user *argp)
++{
++ int ret;
++ struct gasket_page_table_ioctl ibuf;
++ uint max_page_table_size;
++
++ if (copy_from_user(&ibuf, argp, sizeof(struct gasket_page_table_ioctl)))
++ return -EFAULT;
++
++ trace_gasket_ioctl_page_table_data(
++ ibuf.page_table_index, ibuf.size, ibuf.host_address,
++ ibuf.device_address);
++
++ if (ibuf.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++ max_page_table_size = gasket_page_table_max_size(
++ gasket_dev->page_table[ibuf.page_table_index]);
++
++ if (ibuf.size > max_page_table_size) {
++ dev_dbg(gasket_dev->dev,
++ "Partition request 0x%llx too large, max is 0x%x\n",
++ ibuf.size, max_page_table_size);
++ return -EINVAL;
++ }
++
++ mutex_lock(&gasket_dev->mutex);
++
++ ret = gasket_page_table_partition(
++ gasket_dev->page_table[ibuf.page_table_index], ibuf.size);
++ mutex_unlock(&gasket_dev->mutex);
++
++ return ret;
++}
++
++/* Map a userspace buffer to a device virtual address. */
++static int gasket_map_buffers_common(struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl_flags
++ *pibuf)
++{
++ if (pibuf->base.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++
++ if (gasket_page_table_are_addrs_bad(gasket_dev->page_table[pibuf->base.page_table_index],
++ pibuf->base.host_address,
++ pibuf->base.device_address,
++ pibuf->base.size))
++ return -EINVAL;
++
++ return gasket_page_table_map(gasket_dev->page_table[pibuf->base.page_table_index],
++ pibuf->base.host_address,
++ pibuf->base.device_address,
++ pibuf->base.size / PAGE_SIZE,
++ pibuf->flags);
++}
++
++static int gasket_map_buffers(struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl __user *argp)
++{
++ struct gasket_page_table_ioctl_flags ibuf;
++
++ if (copy_from_user(&ibuf.base, argp, sizeof(struct gasket_page_table_ioctl)))
++ return -EFAULT;
++
++ ibuf.flags = 0;
++
++ trace_gasket_ioctl_page_table_data(ibuf.base.page_table_index,
++ ibuf.base.size,
++ ibuf.base.host_address,
++ ibuf.base.device_address);
++
++ return gasket_map_buffers_common(gasket_dev, &ibuf);
++}
++
++static int gasket_map_buffers_flags(struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl_flags __user *argp)
++{
++ struct gasket_page_table_ioctl_flags ibuf;
++
++ if (copy_from_user(&ibuf, argp, sizeof(struct gasket_page_table_ioctl_flags)))
++ return -EFAULT;
++
++ trace_gasket_ioctl_page_table_flags_data(ibuf.base.page_table_index,
++ ibuf.base.size,
++ ibuf.base.host_address,
++ ibuf.base.device_address,
++ ibuf.flags);
++
++ return gasket_map_buffers_common(gasket_dev, &ibuf);
++}
++
++/* Unmap a userspace buffer from a device virtual address. */
++static int gasket_unmap_buffers(struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl __user *argp)
++{
++ struct gasket_page_table_ioctl ibuf;
++
++ if (copy_from_user(&ibuf, argp, sizeof(struct gasket_page_table_ioctl)))
++ return -EFAULT;
++
++ trace_gasket_ioctl_page_table_data(ibuf.page_table_index, ibuf.size,
++ ibuf.host_address,
++ ibuf.device_address);
++
++ if (ibuf.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++
++ if (gasket_page_table_is_dev_addr_bad(gasket_dev->page_table[ibuf.page_table_index],
++ ibuf.device_address, ibuf.size))
++ return -EINVAL;
++
++ gasket_page_table_unmap(gasket_dev->page_table[ibuf.page_table_index],
++ ibuf.device_address, ibuf.size / PAGE_SIZE);
++
++ return 0;
++}
++
++/* Map/unmap dma-buf to/from a device virtual address. */
++static int gasket_map_dmabuf(struct gasket_dev *gasket_dev,
++ struct gasket_page_table_ioctl_dmabuf __user *argp)
++{
++ struct gasket_page_table_ioctl_dmabuf dbuf;
++ struct gasket_page_table *pg_tbl;
++
++ if (copy_from_user(&dbuf, argp, sizeof(dbuf)))
++ return -EFAULT;
++
++ if (dbuf.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++
++ pg_tbl = gasket_dev->page_table[dbuf.page_table_index];
++ if (gasket_page_table_is_dev_addr_bad(pg_tbl,
++ dbuf.device_address,
++ dbuf.num_pages * PAGE_SIZE))
++ return -EINVAL;
++
++ if (dbuf.map)
++ return gasket_page_table_map_dmabuf(pg_tbl,
++ dbuf.dmabuf_fd,
++ dbuf.device_address,
++ dbuf.num_pages,
++ dbuf.flags);
++ else
++ return gasket_page_table_unmap_dmabuf(pg_tbl,
++ dbuf.dmabuf_fd,
++ dbuf.device_address,
++ dbuf.num_pages);
++}
++
++/*
++ * Reserve structures for coherent allocation, and allocate or free the
++ * corresponding memory.
++ */
++static int gasket_config_coherent_allocator(
++ struct gasket_dev *gasket_dev,
++ struct gasket_coherent_alloc_config_ioctl __user *argp)
++{
++ int ret;
++ struct gasket_coherent_alloc_config_ioctl ibuf;
++ dma_addr_t dma_address;
++
++ if (copy_from_user(&ibuf, argp,
++ sizeof(struct gasket_coherent_alloc_config_ioctl)))
++ return -EFAULT;
++
++ trace_gasket_ioctl_config_coherent_allocator(ibuf.enable, ibuf.size,
++ ibuf.dma_address);
++
++ if (ibuf.page_table_index >= gasket_dev->num_page_tables)
++ return -EFAULT;
++
++ if (ibuf.size > PAGE_SIZE * MAX_NUM_COHERENT_PAGES)
++ return -ENOMEM;
++
++ if (ibuf.enable == 0) {
++ dma_address = ibuf.dma_address;
++ ret = gasket_free_coherent_memory(gasket_dev, ibuf.size,
++ dma_address,
++ ibuf.page_table_index);
++ } else {
++ ret = gasket_alloc_coherent_memory(gasket_dev, ibuf.size,
++ &dma_address,
++ ibuf.page_table_index);
++ }
++ if (ret)
++ return ret;
++
++ if (ibuf.enable != 0)
++ ibuf.dma_address = dma_address;
++
++ if (copy_to_user(argp, &ibuf, sizeof(ibuf)))
++ return -EFAULT;
++
++ return 0;
++}
++
++/* Check permissions for Gasket ioctls. */
++static bool gasket_ioctl_check_permissions(struct file *filp, uint cmd)
++{
++ bool alive;
++ bool read, write;
++ struct gasket_dev *gasket_dev = (struct gasket_dev *)filp->private_data;
++
++ alive = (gasket_dev->status == GASKET_STATUS_ALIVE);
++ if (!alive)
++ dev_dbg(gasket_dev->dev, "%s alive %d status %d\n",
++ __func__, alive, gasket_dev->status);
++
++ read = !!(filp->f_mode & FMODE_READ);
++ write = !!(filp->f_mode & FMODE_WRITE);
++
++ switch (cmd) {
++ case GASKET_IOCTL_RESET:
++ case GASKET_IOCTL_CLEAR_INTERRUPT_COUNTS:
++ return write;
++
++ case GASKET_IOCTL_PAGE_TABLE_SIZE:
++ case GASKET_IOCTL_SIMPLE_PAGE_TABLE_SIZE:
++ case GASKET_IOCTL_NUMBER_PAGE_TABLES:
++ return read;
++
++ case GASKET_IOCTL_PARTITION_PAGE_TABLE:
++ case GASKET_IOCTL_CONFIG_COHERENT_ALLOCATOR:
++ return alive && write;
++
++ case GASKET_IOCTL_MAP_BUFFER:
++ case GASKET_IOCTL_MAP_BUFFER_FLAGS:
++ case GASKET_IOCTL_UNMAP_BUFFER:
++ case GASKET_IOCTL_MAP_DMABUF:
++ return alive && write;
++
++ case GASKET_IOCTL_CLEAR_EVENTFD:
++ case GASKET_IOCTL_SET_EVENTFD:
++ return alive && write;
++ }
++
++ return false; /* unknown permissions */
++}
++
++/*
++ * standard ioctl dispatch function.
++ * @filp: File structure pointer describing this node usage session.
++ * @cmd: ioctl number to handle.
++ * @argp: ioctl-specific data pointer.
++ *
++ * Standard ioctl dispatcher; forwards operations to individual handlers.
++ */
++long gasket_handle_ioctl(struct file *filp, uint cmd, void __user *argp)
++{
++ struct gasket_dev *gasket_dev;
++ unsigned long arg = (unsigned long)argp;
++ gasket_ioctl_permissions_cb_t ioctl_permissions_cb;
++ int retval;
++
++ gasket_dev = (struct gasket_dev *)filp->private_data;
++ trace_gasket_ioctl_entry(gasket_dev->dev_info.name, cmd);
++
++ ioctl_permissions_cb = gasket_get_ioctl_permissions_cb(gasket_dev);
++ if (ioctl_permissions_cb) {
++ retval = ioctl_permissions_cb(filp, cmd, argp);
++ if (retval < 0) {
++ trace_gasket_ioctl_exit(retval);
++ return retval;
++ } else if (retval == 0) {
++ trace_gasket_ioctl_exit(-EPERM);
++ return -EPERM;
++ }
++ } else if (!gasket_ioctl_check_permissions(filp, cmd)) {
++ trace_gasket_ioctl_exit(-EPERM);
++ dev_dbg(gasket_dev->dev, "ioctl cmd=%x noperm\n", cmd);
++ return -EPERM;
++ }
++
++ /* Tracing happens in this switch statement for all ioctls with
++ * an integer argrument, but ioctls with a struct argument
++ * that needs copying and decoding, that tracing is done within
++ * the handler call.
++ */
++ switch (cmd) {
++ case GASKET_IOCTL_RESET:
++ retval = gasket_reset(gasket_dev);
++ break;
++ case GASKET_IOCTL_SET_EVENTFD:
++ retval = gasket_set_event_fd(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_CLEAR_EVENTFD:
++ trace_gasket_ioctl_integer_data(arg);
++ retval =
++ gasket_interrupt_clear_eventfd(gasket_dev->interrupt_data,
++ (int)arg);
++ break;
++ case GASKET_IOCTL_PARTITION_PAGE_TABLE:
++ trace_gasket_ioctl_integer_data(arg);
++ retval = gasket_partition_page_table(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_NUMBER_PAGE_TABLES:
++ trace_gasket_ioctl_integer_data(gasket_dev->num_page_tables);
++ if (copy_to_user(argp, &gasket_dev->num_page_tables,
++ sizeof(uint64_t)))
++ retval = -EFAULT;
++ else
++ retval = 0;
++ break;
++ case GASKET_IOCTL_PAGE_TABLE_SIZE:
++ retval = gasket_read_page_table_size(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_SIMPLE_PAGE_TABLE_SIZE:
++ retval = gasket_read_simple_page_table_size(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_MAP_BUFFER:
++ retval = gasket_map_buffers(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_MAP_BUFFER_FLAGS:
++ retval = gasket_map_buffers_flags(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_CONFIG_COHERENT_ALLOCATOR:
++ retval = gasket_config_coherent_allocator(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_UNMAP_BUFFER:
++ retval = gasket_unmap_buffers(gasket_dev, argp);
++ break;
++ case GASKET_IOCTL_CLEAR_INTERRUPT_COUNTS:
++ /* Clear interrupt counts doesn't take an arg, so use 0. */
++ trace_gasket_ioctl_integer_data(0);
++ retval = gasket_interrupt_reset_counts(gasket_dev);
++ break;
++ case GASKET_IOCTL_MAP_DMABUF:
++ retval = gasket_map_dmabuf(gasket_dev, argp);
++ break;
++ default:
++ /* If we don't understand the ioctl, the best we can do is trace
++ * the arg.
++ */
++ trace_gasket_ioctl_integer_data(arg);
++ dev_dbg(gasket_dev->dev,
++ "Unknown ioctl cmd=0x%x not caught by "
++ "gasket_is_supported_ioctl\n",
++ cmd);
++ retval = -EINVAL;
++ break;
++ }
++
++ trace_gasket_ioctl_exit(retval);
++ return retval;
++}
++
++/*
++ * Determines if an ioctl is part of the standard Gasket framework.
++ * @cmd: The ioctl number to handle.
++ *
++ * Returns 1 if the ioctl is supported and 0 otherwise.
++ */
++long gasket_is_supported_ioctl(uint cmd)
++{
++ switch (cmd) {
++ case GASKET_IOCTL_RESET:
++ case GASKET_IOCTL_SET_EVENTFD:
++ case GASKET_IOCTL_CLEAR_EVENTFD:
++ case GASKET_IOCTL_PARTITION_PAGE_TABLE:
++ case GASKET_IOCTL_NUMBER_PAGE_TABLES:
++ case GASKET_IOCTL_PAGE_TABLE_SIZE:
++ case GASKET_IOCTL_SIMPLE_PAGE_TABLE_SIZE:
++ case GASKET_IOCTL_MAP_BUFFER:
++ case GASKET_IOCTL_MAP_BUFFER_FLAGS:
++ case GASKET_IOCTL_UNMAP_BUFFER:
++ case GASKET_IOCTL_MAP_DMABUF:
++ case GASKET_IOCTL_CLEAR_INTERRUPT_COUNTS:
++ case GASKET_IOCTL_CONFIG_COHERENT_ALLOCATOR:
++ return 1;
++ default:
++ return 0;
++ }
++}
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_ioctl.h b/drivers/staging/gasket-driver/gasket_ioctl.h
+--- a/drivers/staging/gasket-driver/gasket_ioctl.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_ioctl.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,28 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/* Copyright (C) 2018 Google, Inc. */
++#ifndef __GASKET_IOCTL_H__
++#define __GASKET_IOCTL_H__
++
++#include "gasket_core.h"
++
++#include <linux/compiler.h>
++
++/*
++ * Handle Gasket common ioctls.
++ * @filp: Pointer to the ioctl's file.
++ * @cmd: Ioctl command.
++ * @arg: Ioctl argument pointer.
++ *
++ * Returns 0 on success and nonzero on failure.
++ */
++long gasket_handle_ioctl(struct file *filp, uint cmd, void __user *argp);
++
++/*
++ * Determines if an ioctl is part of the standard Gasket framework.
++ * @cmd: The ioctl number to handle.
++ *
++ * Returns 1 if the ioctl is supported and 0 otherwise.
++ */
++long gasket_is_supported_ioctl(uint cmd);
++
++#endif
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_page_table.c b/drivers/staging/gasket-driver/gasket_page_table.c
+--- a/drivers/staging/gasket-driver/gasket_page_table.c 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_page_table.c 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,1597 @@
++// SPDX-License-Identifier: GPL-2.0
++/*
++ * Implementation of Gasket page table support.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++
++/*
++ * Implementation of Gasket page table support.
++ *
++ * This file assumes 4kB pages throughout; can be factored out when necessary.
++ *
++ * There is a configurable number of page table entries, as well as a
++ * configurable bit index for the extended address flag. Both of these are
++ * specified in gasket_page_table_init through the page_table_config parameter.
++ *
++ * The following example assumes:
++ * page_table_config->total_entries = 8192
++ * page_table_config->extended_bit = 63
++ *
++ * Address format:
++ * Simple addresses - those whose containing pages are directly placed in the
++ * device's address translation registers - are laid out as:
++ * [ 63 - 25: 0 | 24 - 12: page index | 11 - 0: page offset ]
++ * page index: The index of the containing page in the device's address
++ * translation registers.
++ * page offset: The index of the address into the containing page.
++ *
++ * Extended address - those whose containing pages are contained in a second-
++ * level page table whose address is present in the device's address translation
++ * registers - are laid out as:
++ * [ 63: flag | 62 - 34: 0 | 33 - 21: dev/level 0 index |
++ * 20 - 12: host/level 1 index | 11 - 0: page offset ]
++ * flag: Marker indicating that this is an extended address. Always 1.
++ * dev index: The index of the first-level page in the device's extended
++ * address translation registers.
++ * host index: The index of the containing page in the [host-resident] second-
++ * level page table.
++ * page offset: The index of the address into the containing [second-level]
++ * page.
++ */
++#include "gasket_page_table.h"
++
++#include <linux/device.h>
++#include <linux/dma-buf.h>
++#include <linux/file.h>
++#include <linux/init.h>
++#include <linux/kernel.h>
++#include <linux/list.h>
++#include <linux/module.h>
++#include <linux/moduleparam.h>
++#include <linux/pagemap.h>
++#include <linux/version.h>
++#include <linux/vmalloc.h>
++
++#if __has_include(<linux/dma-buf.h>)
++MODULE_IMPORT_NS(DMA_BUF);
++#endif
++
++#include "gasket_constants.h"
++#include "gasket_core.h"
++
++/* Constants & utility macros */
++/* The number of pages that can be mapped into each second-level page table. */
++#define GASKET_PAGES_PER_SUBTABLE 512
++
++/* The starting position of the page index in a simple virtual address. */
++#define GASKET_SIMPLE_PAGE_SHIFT 12
++
++/* Flag indicating that a [device] slot is valid for use. */
++#define GASKET_VALID_SLOT_FLAG 1
++
++/*
++ * The starting position of the level 0 page index (i.e., the entry in the
++ * device's extended address registers) in an extended address.
++ * Also can be thought of as (log2(PAGE_SIZE) + log2(PAGES_PER_SUBTABLE)),
++ * or (12 + 9).
++ */
++#define GASKET_EXTENDED_LVL0_SHIFT 21
++
++/*
++ * Number of first level pages that Gasket chips support. Equivalent to
++ * log2(NUM_LVL0_PAGE_TABLES)
++ *
++ * At a maximum, allowing for a 34 bits address space (or 16GB)
++ * = GASKET_EXTENDED_LVL0_WIDTH + (log2(PAGE_SIZE) + log2(PAGES_PER_SUBTABLE)
++ * or, = 13 + 9 + 12
++ */
++#define GASKET_EXTENDED_LVL0_WIDTH 13
++
++/*
++ * The starting position of the level 1 page index (i.e., the entry in the
++ * host second-level/sub- table) in an extended address.
++ */
++#define GASKET_EXTENDED_LVL1_SHIFT 12
++
++/*
++ * Utilities for accessing flags bitfields.
++ */
++#define MASK(field) (((1u << field##_WIDTH) - 1) << field##_SHIFT)
++#define GET(field, flags) (((flags) & MASK(field)) >> field##_SHIFT)
++#define SET(field, flags, val) (((flags) & ~MASK(field)) | ((val) << field##_SHIFT))
++
++#define FLAGS_STATUS_SHIFT 0
++#define FLAGS_STATUS_WIDTH 1
++
++#define FLAGS_DMA_DIRECTION_SHIFT 1
++#define FLAGS_DMA_DIRECTION_WIDTH 2
++
++/* Type declarations */
++/* Valid states for a struct gasket_page_table_entry. */
++enum pte_status {
++ PTE_FREE,
++ PTE_INUSE,
++};
++
++/*
++ * Mapping metadata for a single page.
++ *
++ * In this file, host-side page table entries are referred to as that (or PTEs).
++ * Where device vs. host entries are differentiated, device-side or -visible
++ * entries are called "slots". A slot may be either an entry in the device's
++ * address translation table registers or an entry in a second-level page
++ * table ("subtable").
++ *
++ * The full data in this structure is visible on the host [of course]. Only
++ * the address contained in dma_addr is communicated to the device; that points
++ * to the actual page mapped and described by this structure.
++ */
++struct gasket_page_table_entry {
++ /*
++ * Internal structure matches gasket_page_table_ioctl_flags.flags.
++ * NOTE: All fields should have a default value of 0. This ensures that
++ * the kernel will be backwards compatible with old drivers.
++ */
++ u32 flags;
++
++ /*
++ * Index for alignment into host vaddrs.
++ * When a user specifies a host address for a mapping, that address may
++ * not be page-aligned. Offset is the index into the containing page of
++ * the host address (i.e., host_vaddr & (PAGE_SIZE - 1)).
++ * This is necessary for translating between user-specified addresses
++ * and page-aligned addresses.
++ */
++ int offset;
++
++ /* Address of the page in DMA space. */
++ dma_addr_t dma_addr;
++
++ /* Linux page descriptor for the page described by this structure. */
++ struct page *page;
++
++ /*
++ * If this is an extended and first-level entry, sublevel points
++ * to the second-level entries underneath this entry.
++ */
++ struct gasket_page_table_entry *sublevel;
++};
++
++/*
++ * Maintains virtual to physical address mapping for a coherent page that is
++ * allocated by this module for a given device.
++ * Note that coherent pages mappings virt mapping cannot be tracked by the
++ * Linux kernel, and coherent pages don't have a struct page associated,
++ * hence Linux kernel cannot perform a get_user_page_xx() on a phys address
++ * that was allocated coherent.
++ * This structure trivially implements this mechanism.
++ */
++struct gasket_coherent_page_entry {
++ /* Phys address, dma'able by the owner device */
++ dma_addr_t paddr;
++
++ /* Kernel virtual address */
++ u64 user_virt;
++
++ /* User virtual address that was mapped by the mmap kernel subsystem */
++ dma_addr_t kernel_virt;
++
++ /*
++ * Whether this page has been mapped into a user land process virtual
++ * space
++ */
++ u32 in_use;
++};
++
++/* Storage for dmabuf mapping information. */
++struct gasket_dmabuf_mapping {
++ struct dma_buf *dmabuf;
++ struct dma_buf_attachment *attachment;
++ struct sg_table *sgt;
++ enum dma_data_direction direction;
++ struct list_head list;
++};
++
++/*
++ * [Host-side] page table descriptor.
++ *
++ * This structure tracks the metadata necessary to manage both simple and
++ * extended page tables.
++ */
++struct gasket_page_table {
++ /* The config used to create this page table. */
++ struct gasket_page_table_config config;
++
++ /* The number of simple (single-level) entries in the page table. */
++ uint num_simple_entries;
++
++ /* The number of extended (two-level) entries in the page table. */
++ uint num_extended_entries;
++
++ /* Array of [host-side] page table entries. */
++ struct gasket_page_table_entry *entries;
++
++ /* Number of actively mapped kernel pages in this table. */
++ uint num_active_pages;
++
++ /* Device register: base of/first slot in the page table. */
++ u64 __iomem *base_slot;
++
++ /* Device register: holds the offset indicating the start of the
++ * extended address region of the device's address translation table.
++ */
++ u64 __iomem *extended_offset_reg;
++
++ /* Device structure for the underlying device. Only used for logging. */
++ struct device *device;
++
++ /* PCI system descriptor for the underlying device. */
++ struct pci_dev *pci_dev;
++
++ /* Location of the extended address bit for this Gasket device. */
++ u64 extended_flag;
++
++ /* Mutex to protect page table internals. */
++ struct mutex mutex;
++
++ /* Number of coherent pages accessible thru by this page table */
++ int num_coherent_pages;
++
++ /*
++ * List of coherent memory (physical) allocated for a device.
++ *
++ * This structure also remembers the user virtual mapping, this is
++ * hacky, but we need to do this because the kernel doesn't keep track
++ * of the user coherent pages (pfn pages), and virt to coherent page
++ * mapping.
++ * TODO: use find_vma() APIs to convert host address to vm_area, to
++ * dma_addr_t instead of storing user virtu address in
++ * gasket_coherent_page_entry
++ *
++ * Note that the user virtual mapping is created by the driver, in
++ * gasket_mmap function, so user_virt belongs in the driver anyhow.
++ */
++ struct gasket_coherent_page_entry *coherent_pages;
++
++ /* List of dmabufs currently attached and mapped. */
++ struct list_head dmabufs;
++};
++
++/* See gasket_page_table.h for description. */
++int gasket_page_table_init(struct gasket_page_table **ppg_tbl,
++ const struct gasket_bar_data *bar_data,
++ const struct gasket_page_table_config *page_table_config,
++ struct device *device, struct pci_dev *pci_dev)
++{
++ ulong bytes;
++ struct gasket_page_table *pg_tbl;
++ ulong total_entries = page_table_config->total_entries;
++
++ /*
++ * TODO: Verify config->total_entries against value read from the
++ * hardware register that contains the page table size.
++ */
++ if (total_entries == ULONG_MAX) {
++ dev_dbg(device, "Error reading page table size. "
++ "Initializing page table with size 0\n");
++ total_entries = 0;
++ }
++
++ dev_dbg(device,
++ "Attempting to initialize page table of size 0x%lx\n",
++ total_entries);
++
++ dev_dbg(device,
++ "Table has base reg 0x%x, extended offset reg 0x%x\n",
++ page_table_config->base_reg,
++ page_table_config->extended_reg);
++
++ *ppg_tbl = kzalloc(sizeof(**ppg_tbl), GFP_KERNEL);
++ if (!*ppg_tbl) {
++ dev_dbg(device, "No memory for page table\n");
++ return -ENOMEM;
++ }
++
++ pg_tbl = *ppg_tbl;
++ bytes = total_entries * sizeof(struct gasket_page_table_entry);
++ if (bytes != 0) {
++ pg_tbl->entries = vzalloc(bytes);
++ if (!pg_tbl->entries) {
++ dev_dbg(device,
++ "No memory for address translation metadata\n");
++ kfree(pg_tbl);
++ *ppg_tbl = NULL;
++ return -ENOMEM;
++ }
++ }
++
++ mutex_init(&pg_tbl->mutex);
++ memcpy(&pg_tbl->config, page_table_config, sizeof(*page_table_config));
++ if (pg_tbl->config.mode == GASKET_PAGE_TABLE_MODE_NORMAL ||
++ pg_tbl->config.mode == GASKET_PAGE_TABLE_MODE_SIMPLE) {
++ pg_tbl->num_simple_entries = total_entries;
++ pg_tbl->num_extended_entries = 0;
++ pg_tbl->extended_flag = 1ull << page_table_config->extended_bit;
++ } else {
++ pg_tbl->num_simple_entries = 0;
++ pg_tbl->num_extended_entries = total_entries;
++ pg_tbl->extended_flag = 0;
++ }
++ pg_tbl->num_active_pages = 0;
++ pg_tbl->base_slot =
++ (u64 __iomem *)&bar_data->virt_base[page_table_config->base_reg];
++ pg_tbl->extended_offset_reg =
++ (u64 __iomem *)&bar_data->virt_base[page_table_config->extended_reg];
++ pg_tbl->device = get_device(device);
++ pg_tbl->pci_dev = pci_dev;
++ INIT_LIST_HEAD(&pg_tbl->dmabufs);
++
++ dev_dbg(device, "Page table initialized successfully\n");
++
++ return 0;
++}
++
++/*
++ * Check if a range of PTEs is free.
++ * The page table mutex must be held by the caller.
++ */
++static bool gasket_is_pte_range_free(struct gasket_page_table_entry *ptes,
++ uint num_entries)
++{
++ int i;
++
++ for (i = 0; i < num_entries; i++) {
++ if (GET(FLAGS_STATUS, ptes[i].flags) != PTE_FREE)
++ return false;
++ }
++
++ return true;
++}
++
++/*
++ * Free a second level page [sub]table.
++ * The page table mutex must be held before this call.
++ */
++static void gasket_free_extended_subtable(struct gasket_page_table *pg_tbl,
++ struct gasket_page_table_entry *pte,
++ u64 __iomem *slot)
++{
++ /* Release the page table from the driver */
++ pte->flags = SET(FLAGS_STATUS, pte->flags, PTE_FREE);
++
++ /* Release the page table from the device */
++ writeq(0, slot);
++
++ if (pte->dma_addr)
++ dma_unmap_page(pg_tbl->device, pte->dma_addr, PAGE_SIZE,
++ DMA_TO_DEVICE);
++
++ vfree(pte->sublevel);
++
++ if (pte->page)
++ free_page((ulong)page_address(pte->page));
++
++ memset(pte, 0, sizeof(struct gasket_page_table_entry));
++}
++
++/*
++ * Actually perform collection.
++ * The page table mutex must be held by the caller.
++ */
++static void
++gasket_page_table_garbage_collect_nolock(struct gasket_page_table *pg_tbl)
++{
++ struct gasket_page_table_entry *pte;
++ u64 __iomem *slot;
++
++ /* XXX FIX ME XXX -- more efficient to keep a usage count */
++ /* rather than scanning the second level page tables */
++
++ for (pte = pg_tbl->entries + pg_tbl->num_simple_entries,
++ slot = pg_tbl->base_slot + pg_tbl->num_simple_entries;
++ pte < pg_tbl->entries + pg_tbl->config.total_entries;
++ pte++, slot++) {
++ if (GET(FLAGS_STATUS, pte->flags) == PTE_INUSE) {
++ if (gasket_is_pte_range_free(pte->sublevel,
++ GASKET_PAGES_PER_SUBTABLE))
++ gasket_free_extended_subtable(pg_tbl, pte,
++ slot);
++ }
++ }
++}
++
++/* See gasket_page_table.h for description. */
++void gasket_page_table_garbage_collect(struct gasket_page_table *pg_tbl)
++{
++ mutex_lock(&pg_tbl->mutex);
++ gasket_page_table_garbage_collect_nolock(pg_tbl);
++ mutex_unlock(&pg_tbl->mutex);
++}
++
++/* See gasket_page_table.h for description. */
++void gasket_page_table_cleanup(struct gasket_page_table *pg_tbl)
++{
++ /* Deallocate free second-level tables. */
++ gasket_page_table_garbage_collect(pg_tbl);
++
++ /* TODO: Check that all PTEs have been freed? */
++
++ vfree(pg_tbl->entries);
++ pg_tbl->entries = NULL;
++
++ put_device(pg_tbl->device);
++ kfree(pg_tbl);
++}
++
++/* See gasket_page_table.h for description. */
++int gasket_page_table_partition(struct gasket_page_table *pg_tbl,
++ uint num_simple_entries)
++{
++ int i, start;
++
++ mutex_lock(&pg_tbl->mutex);
++ if (num_simple_entries > pg_tbl->config.total_entries) {
++ mutex_unlock(&pg_tbl->mutex);
++ return -EINVAL;
++ }
++
++ gasket_page_table_garbage_collect_nolock(pg_tbl);
++
++ start = min(pg_tbl->num_simple_entries, num_simple_entries);
++
++ for (i = start; i < pg_tbl->config.total_entries; i++) {
++ if (GET(FLAGS_STATUS, pg_tbl->entries[i].flags) != PTE_FREE) {
++ dev_err(pg_tbl->device, "entry %d is not free\n", i);
++ mutex_unlock(&pg_tbl->mutex);
++ return -EBUSY;
++ }
++ }
++
++ pg_tbl->num_simple_entries = num_simple_entries;
++ pg_tbl->num_extended_entries =
++ pg_tbl->config.total_entries - num_simple_entries;
++ writeq(num_simple_entries, pg_tbl->extended_offset_reg);
++
++ mutex_unlock(&pg_tbl->mutex);
++ return 0;
++}
++EXPORT_SYMBOL(gasket_page_table_partition);
++
++/*
++ * Return whether a host buffer was mapped as coherent memory.
++ *
++ * A Gasket page_table currently support one contiguous dma range, mapped to one
++ * contiguous virtual memory range. Check if the host_addr is within that range.
++ */
++static int is_coherent(struct gasket_page_table *pg_tbl, ulong host_addr)
++{
++ u64 min, max;
++
++ /* whether the host address is within user virt range */
++ if (!pg_tbl->coherent_pages)
++ return 0;
++
++ min = (u64)pg_tbl->coherent_pages[0].user_virt;
++ max = min + PAGE_SIZE * pg_tbl->num_coherent_pages;
++
++ return min <= host_addr && host_addr < max;
++}
++
++/* Safely return a page to the OS. */
++static bool gasket_release_page(struct page *page)
++{
++ if (!page)
++ return false;
++
++ if (!PageReserved(page))
++ SetPageDirty(page);
++ put_page(page);
++
++ return true;
++}
++
++/*
++ * Get and map last level page table buffers.
++ *
++ * slots is the location(s) to write device-mapped page address. If this is a
++ * simple mapping, these will be address translation registers. If this is
++ * an extended mapping, these will be within a second-level page table
++ * allocated by the host and so must have their __iomem attribute casted away.
++ */
++static int gasket_perform_mapping(struct gasket_page_table *pg_tbl,
++ struct gasket_page_table_entry *ptes,
++ u64 __iomem *slots,
++ struct sg_page_iter *sg_iter,
++ ulong host_addr,
++ uint num_pages, u32 flags,
++ int is_simple_mapping)
++{
++ int ret;
++ ulong offset;
++ struct page *page;
++ dma_addr_t dma_addr;
++ ulong page_addr;
++ int i;
++ enum dma_data_direction direction;
++
++ /* Must have a virtual host address or a sg iterator, but not both. */
++ if (!((uintptr_t)host_addr ^ (uintptr_t)sg_iter)) {
++ dev_err(pg_tbl->device, "need sg_iter or host_addr\n");
++ return -EINVAL;
++ }
++
++ direction = GET(FLAGS_DMA_DIRECTION, flags);
++ if (direction == DMA_NONE) {
++ dev_err(pg_tbl->device, "invalid DMA direction flags=0x%lx\n",
++ (unsigned long)flags);
++ return -EINVAL;
++ }
++
++ for (i = 0; i < num_pages; i++) {
++ page_addr = host_addr + i * PAGE_SIZE;
++ offset = page_addr & (PAGE_SIZE - 1);
++ dev_dbg(pg_tbl->device, "%s i %d\n", __func__, i);
++ if (sg_iter) {
++ if (!__sg_page_iter_next(sg_iter))
++ return -EINVAL;
++
++ /* Page already mapped for DMA. */
++#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0)
++ ptes[i].dma_addr = sg_page_iter_dma_address(sg_iter);
++#else
++ ptes[i].dma_addr = sg_page_iter_dma_address(
++ container_of(sg_iter, struct sg_dma_page_iter, base));
++#endif
++ ptes[i].page = NULL;
++ offset = 0;
++ } else if (is_coherent(pg_tbl, host_addr)) {
++ u64 off =
++ (u64)host_addr -
++ (u64)pg_tbl->coherent_pages[0].user_virt;
++ ptes[i].page = NULL;
++ ptes[i].offset = offset;
++ ptes[i].dma_addr = pg_tbl->coherent_pages[0].paddr +
++ off + i * PAGE_SIZE;
++ } else {
++ ret = get_user_pages_fast(page_addr - offset, 1,
++ direction != DMA_TO_DEVICE,
++ &page);
++
++ if (ret <= 0) {
++ dev_err(pg_tbl->device,
++ "get user pages failed for addr=0x%lx, "
++ "offset=0x%lx [ret=%d]\n",
++ page_addr, offset, ret);
++ return ret ? ret : -ENOMEM;
++ }
++ ++pg_tbl->num_active_pages;
++
++ ptes[i].page = page;
++ ptes[i].offset = offset;
++
++ /* Map the page into DMA space. */
++ ptes[i].dma_addr = dma_map_page(pg_tbl->device, page, 0, PAGE_SIZE,
++ GET(FLAGS_DMA_DIRECTION, flags));
++ dev_dbg(pg_tbl->device,
++ "%s i %d pte %p pfn %p -> mapped %llx\n",
++ __func__, i, &ptes[i],
++ (void *)page_to_pfn(page),
++ (unsigned long long)ptes[i].dma_addr);
++
++ if (dma_mapping_error(pg_tbl->device,
++ ptes[i].dma_addr)) {
++ dev_dbg(pg_tbl->device,
++ "%s i %d -> fail to map page %llx "
++ "[pfn %p phys %p]\n",
++ __func__, i,
++ (unsigned long long)ptes[i].dma_addr,
++ (void *)page_to_pfn(page),
++ (void *)page_to_phys(page));
++
++ /* clean up */
++ if (gasket_release_page(ptes[i].page))
++ --pg_tbl->num_active_pages;
++
++ memset(&ptes[i], 0, sizeof(struct gasket_page_table_entry));
++ return -EINVAL;
++ }
++ }
++
++ /* Make the DMA-space address available to the device. */
++ dma_addr = (ptes[i].dma_addr + offset) | GASKET_VALID_SLOT_FLAG;
++
++ if (is_simple_mapping)
++ writeq(dma_addr, &slots[i]);
++ else
++ ((u64 __force *)slots)[i] = dma_addr;
++
++ /* Set PTE flags equal to flags param with STATUS=PTE_INUSE. */
++ ptes[i].flags = SET(FLAGS_STATUS, flags, PTE_INUSE);
++ }
++ return 0;
++}
++
++/*
++ * Return the index of the page for the address in the simple table.
++ * Does not perform validity checking.
++ */
++static int gasket_simple_page_idx(struct gasket_page_table *pg_tbl,
++ u64 dev_addr)
++{
++ return (dev_addr >> GASKET_SIMPLE_PAGE_SHIFT) &
++ (pg_tbl->config.total_entries - 1);
++}
++
++/*
++ * Return the level 0 page index for the given address.
++ * Does not perform validity checking.
++ */
++static ulong gasket_extended_lvl0_page_idx(struct gasket_page_table *pg_tbl,
++ u64 dev_addr)
++{
++ return (dev_addr >> GASKET_EXTENDED_LVL0_SHIFT) &
++ (pg_tbl->config.total_entries - 1);
++}
++
++/*
++ * Return the level 1 page index for the given address.
++ * Does not perform validity checking.
++ */
++static ulong gasket_extended_lvl1_page_idx(struct gasket_page_table *pg_tbl,
++ u64 dev_addr)
++{
++ return (dev_addr >> GASKET_EXTENDED_LVL1_SHIFT) &
++ (GASKET_PAGES_PER_SUBTABLE - 1);
++}
++
++/*
++ * Allocate page table entries in a simple table.
++ * The page table mutex must be held by the caller.
++ */
++static int gasket_alloc_simple_entries(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_pages)
++{
++ if (!gasket_is_pte_range_free(pg_tbl->entries +
++ gasket_simple_page_idx(pg_tbl, dev_addr),
++ num_pages))
++ return -EBUSY;
++
++ return 0;
++}
++
++/*
++ * Unmap and release mapped pages.
++ * The page table mutex must be held by the caller.
++ */
++static void gasket_perform_unmapping(struct gasket_page_table *pg_tbl,
++ struct gasket_page_table_entry *ptes,
++ u64 __iomem *slots, uint num_pages,
++ int is_simple_mapping)
++{
++ int i;
++ /*
++ * For each page table entry and corresponding entry in the device's
++ * address translation table:
++ */
++ for (i = 0; i < num_pages; i++) {
++ /* release the address from the device, */
++ if (is_simple_mapping)
++ writeq(0, &slots[i]);
++ else
++ ((u64 __force *)slots)[i] = 0;
++
++ /* release the address from the driver, */
++ if (GET(FLAGS_STATUS, ptes[i].flags) == PTE_INUSE) {
++ if (ptes[i].page && ptes[i].dma_addr) {
++ dma_unmap_page(pg_tbl->device, ptes[i].dma_addr, PAGE_SIZE,
++ GET(FLAGS_DMA_DIRECTION, ptes[i].flags));
++ }
++ if (gasket_release_page(ptes[i].page))
++ --pg_tbl->num_active_pages;
++ }
++
++ /* and clear the PTE. */
++ memset(&ptes[i], 0, sizeof(struct gasket_page_table_entry));
++ }
++}
++
++/*
++ * Unmap and release pages mapped to simple addresses.
++ * The page table mutex must be held by the caller.
++ */
++static void gasket_unmap_simple_pages(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_pages)
++{
++ uint slot = gasket_simple_page_idx(pg_tbl, dev_addr);
++
++ gasket_perform_unmapping(pg_tbl, pg_tbl->entries + slot,
++ pg_tbl->base_slot + slot, num_pages, 1);
++}
++
++/*
++ * Unmap and release buffers to extended addresses.
++ * The page table mutex must be held by the caller.
++ */
++static void gasket_unmap_extended_pages(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_pages)
++{
++ uint slot_idx, remain, len;
++ struct gasket_page_table_entry *pte;
++ u64 __iomem *slot_base;
++
++ remain = num_pages;
++ slot_idx = gasket_extended_lvl1_page_idx(pg_tbl, dev_addr);
++ pte = pg_tbl->entries + pg_tbl->num_simple_entries +
++ gasket_extended_lvl0_page_idx(pg_tbl, dev_addr);
++
++ while (remain > 0) {
++ /* TODO: Add check to ensure pte remains valid? */
++ len = min(remain, GASKET_PAGES_PER_SUBTABLE - slot_idx);
++
++ if (GET(FLAGS_STATUS, pte->flags) == PTE_INUSE) {
++ slot_base = (u64 __iomem *)(page_address(pte->page) +
++ pte->offset);
++ gasket_perform_unmapping(pg_tbl,
++ pte->sublevel + slot_idx,
++ slot_base + slot_idx, len, 0);
++ /*
++ * Extended page tables are in DRAM so they need to be
++ * synced each time they are updated.
++ */
++ dma_sync_single_for_device(pg_tbl->device,
++ pte->dma_addr + slot_idx * sizeof(u64),
++ len * sizeof(u64), DMA_TO_DEVICE);
++ }
++
++ remain -= len;
++ slot_idx = 0;
++ pte++;
++ }
++}
++
++/* Evaluates to nonzero if the specified virtual address is simple. */
++static inline bool gasket_addr_is_simple(struct gasket_page_table *pg_tbl,
++ u64 addr)
++{
++ return !((addr) & (pg_tbl)->extended_flag);
++}
++
++/*
++ * Convert (simple, page, offset) into a device address.
++ * Examples:
++ * Simple page 0, offset 32:
++ * Input (1, 0, 32), Output 0x20
++ * Simple page 1000, offset 511:
++ * Input (1, 1000, 511), Output 0x3E81FF
++ * Extended page 0, offset 32:
++ * Input (0, 0, 32), Output 0x8000000020
++ * Extended page 1000, offset 511:
++ * Input (0, 1000, 511), Output 0x8003E81FF
++ */
++static u64 gasket_components_to_dev_address(struct gasket_page_table *pg_tbl,
++ int is_simple, uint page_index,
++ uint offset)
++{
++ u64 dev_addr = (page_index << GASKET_SIMPLE_PAGE_SHIFT) | offset;
++
++ return is_simple ? dev_addr : (pg_tbl->extended_flag | dev_addr);
++}
++
++/*
++ * Validity checking for simple addresses.
++ *
++ * Verify that address translation commutes (from address to/from page + offset)
++ * and that the requested page range starts and ends within the set of
++ * currently-partitioned simple pages.
++ */
++static bool gasket_is_simple_dev_addr_bad(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_pages)
++{
++ ulong page_offset = dev_addr & (PAGE_SIZE - 1);
++ ulong page_index =
++ (dev_addr / PAGE_SIZE) & (pg_tbl->config.total_entries - 1);
++
++ if (gasket_components_to_dev_address(pg_tbl, 1, page_index,
++ page_offset) != dev_addr) {
++ dev_err(pg_tbl->device, "address is invalid, 0x%llX\n",
++ dev_addr);
++ return true;
++ }
++
++ if (page_index >= pg_tbl->num_simple_entries) {
++ dev_err(pg_tbl->device,
++ "starting slot at %lu is too large, max is < %u\n",
++ page_index, pg_tbl->num_simple_entries);
++ return true;
++ }
++
++ if (page_index + num_pages > pg_tbl->num_simple_entries) {
++ dev_err(pg_tbl->device,
++ "ending slot at %lu is too large, max is <= %u\n",
++ page_index + num_pages, pg_tbl->num_simple_entries);
++ return true;
++ }
++
++ return false;
++}
++
++/*
++ * Validity checking for extended addresses.
++ *
++ * Verify that address translation commutes (from address to/from page +
++ * offset) and that the requested page range starts and ends within the set of
++ * currently-partitioned extended pages.
++ */
++static bool gasket_is_extended_dev_addr_bad(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_pages)
++{
++ /* Starting byte index of dev_addr into the first mapped page */
++ ulong page_offset = dev_addr & (PAGE_SIZE - 1);
++ ulong page_global_idx, page_lvl0_idx;
++ ulong num_lvl0_pages;
++ u64 addr;
++
++ /* check if the device address is out of bound */
++ addr = dev_addr & ~((pg_tbl)->extended_flag);
++ if (addr >> (GASKET_EXTENDED_LVL0_WIDTH + GASKET_EXTENDED_LVL0_SHIFT)) {
++ dev_err(pg_tbl->device,
++ "device address out of bounds: 0x%llx\n", dev_addr);
++ return true;
++ }
++
++ /* Find the starting sub-page index in the space of all sub-pages. */
++ page_global_idx = (dev_addr / PAGE_SIZE) &
++ (pg_tbl->config.total_entries * GASKET_PAGES_PER_SUBTABLE - 1);
++
++ /* Find the starting level 0 index. */
++ page_lvl0_idx = gasket_extended_lvl0_page_idx(pg_tbl, dev_addr);
++
++ /* Get the count of affected level 0 pages. */
++ num_lvl0_pages = (num_pages + GASKET_PAGES_PER_SUBTABLE - 1) /
++ GASKET_PAGES_PER_SUBTABLE;
++
++ if (gasket_components_to_dev_address(pg_tbl, 0, page_global_idx,
++ page_offset) != dev_addr) {
++ dev_err(pg_tbl->device, "address is invalid: 0x%llx\n",
++ dev_addr);
++ return true;
++ }
++
++ if (page_lvl0_idx >= pg_tbl->num_extended_entries) {
++ dev_err(pg_tbl->device,
++ "starting level 0 slot at %lu is too large, max is < "
++ "%u\n", page_lvl0_idx, pg_tbl->num_extended_entries);
++ return true;
++ }
++
++ if (page_lvl0_idx + num_lvl0_pages > pg_tbl->num_extended_entries) {
++ dev_err(pg_tbl->device,
++ "ending level 0 slot at %lu is too large, max is <= %u\n",
++ page_lvl0_idx + num_lvl0_pages,
++ pg_tbl->num_extended_entries);
++ return true;
++ }
++
++ return false;
++}
++
++/*
++ * Non-locking entry to unmapping routines.
++ * The page table mutex must be held by the caller.
++ */
++static void gasket_page_table_unmap_nolock(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_pages)
++{
++ if (!num_pages)
++ return;
++
++ if (gasket_addr_is_simple(pg_tbl, dev_addr))
++ gasket_unmap_simple_pages(pg_tbl, dev_addr, num_pages);
++ else
++ gasket_unmap_extended_pages(pg_tbl, dev_addr, num_pages);
++}
++
++/*
++ * Allocate and map pages to simple addresses.
++ * If there is an error, no pages are mapped.
++ */
++static int gasket_map_simple_pages(struct gasket_page_table *pg_tbl,
++ struct sg_page_iter *sg_iter,
++ ulong host_addr, u64 dev_addr,
++ uint num_pages, u32 flags)
++{
++ int ret;
++ uint slot_idx = gasket_simple_page_idx(pg_tbl, dev_addr);
++
++ ret = gasket_alloc_simple_entries(pg_tbl, dev_addr, num_pages);
++ if (ret) {
++ dev_err(pg_tbl->device,
++ "page table slots %u (@ 0x%llx) to %u are not available\n",
++ slot_idx, (long long unsigned int)dev_addr,
++ slot_idx + num_pages - 1);
++ return ret;
++ }
++
++ ret = gasket_perform_mapping(pg_tbl, pg_tbl->entries + slot_idx,
++ pg_tbl->base_slot + slot_idx, sg_iter,
++ host_addr, num_pages, flags, 1);
++
++ if (ret) {
++ gasket_page_table_unmap_nolock(pg_tbl, dev_addr, num_pages);
++ dev_err(pg_tbl->device, "gasket_perform_mapping %d\n", ret);
++ }
++ return ret;
++}
++
++/*
++ * Allocate a second level page table.
++ * The page table mutex must be held by the caller.
++ */
++static int gasket_alloc_extended_subtable(struct gasket_page_table *pg_tbl,
++ struct gasket_page_table_entry *pte,
++ u64 __iomem *slot)
++{
++ ulong page_addr, subtable_bytes;
++ dma_addr_t dma_addr;
++
++ /* XXX FIX ME XXX this is inefficient for non-4K page sizes */
++
++ /* GFP_DMA flag must be passed to architectures for which
++ * part of the memory range is not considered DMA'able.
++ * This seems to be the case for Juno board with 4.5.0 Linaro kernel
++ */
++ page_addr = get_zeroed_page(GFP_KERNEL | GFP_DMA);
++ if (!page_addr)
++ return -ENOMEM;
++ pte->page = virt_to_page((void *)page_addr);
++ pte->offset = 0;
++
++ subtable_bytes = sizeof(struct gasket_page_table_entry) *
++ GASKET_PAGES_PER_SUBTABLE;
++ pte->sublevel = vzalloc(subtable_bytes);
++ if (!pte->sublevel) {
++ free_page(page_addr);
++ memset(pte, 0, sizeof(struct gasket_page_table_entry));
++ return -ENOMEM;
++ }
++
++ /* Map the page into DMA space. */
++ pte->dma_addr = dma_map_page(pg_tbl->device, pte->page, 0, PAGE_SIZE,
++ DMA_TO_DEVICE);
++ if (dma_mapping_error(pg_tbl->device, pte->dma_addr)) {
++ dev_dbg(pg_tbl->device,
++ "%s -> fail to map page %llx "
++ "[pfn %p phys %p]\n",
++ __func__,
++ (unsigned long long)pte->dma_addr,
++ (void *)page_to_pfn(pte->page),
++ (void *)page_to_phys(pte->page));
++
++ /* clean up */
++ free_page(page_addr);
++ vfree(pte->sublevel);
++ memset(pte, 0, sizeof(struct gasket_page_table_entry));
++
++ return -ENOMEM;
++ }
++
++ /* make the addresses available to the device */
++ dma_addr = (pte->dma_addr + pte->offset) | GASKET_VALID_SLOT_FLAG;
++ writeq(dma_addr, slot);
++
++ pte->flags = SET(FLAGS_STATUS, pte->flags, PTE_INUSE);
++
++ return 0;
++}
++
++/*
++ * Allocate slots in an extended page table. Check to see if a range of page
++ * table slots are available. If necessary, memory is allocated for second level
++ * page tables.
++ *
++ * Note that memory for second level page tables is allocated as needed, but
++ * that memory is only freed on the final close of the device file, when the
++ * page tables are repartitioned, or the the device is removed. If there is an
++ * error or if the full range of slots is not available, any memory
++ * allocated for second level page tables remains allocated until final close,
++ * repartition, or device removal.
++ *
++ * The page table mutex must be held by the caller.
++ */
++static int gasket_alloc_extended_entries(struct gasket_page_table *pg_tbl,
++ u64 dev_addr, uint num_entries)
++{
++ int ret = 0;
++ uint remain, subtable_slot_idx, len;
++ struct gasket_page_table_entry *pte;
++ u64 __iomem *slot;
++
++ remain = num_entries;
++ subtable_slot_idx = gasket_extended_lvl1_page_idx(pg_tbl, dev_addr);
++ pte = pg_tbl->entries + pg_tbl->num_simple_entries +
++ gasket_extended_lvl0_page_idx(pg_tbl, dev_addr);
++ slot = pg_tbl->base_slot + pg_tbl->num_simple_entries +
++ gasket_extended_lvl0_page_idx(pg_tbl, dev_addr);
++
++ while (remain > 0) {
++ len = min(remain,
++ GASKET_PAGES_PER_SUBTABLE - subtable_slot_idx);
++
++ if (GET(FLAGS_STATUS, pte->flags) == PTE_FREE) {
++ ret = gasket_alloc_extended_subtable(pg_tbl, pte, slot);
++ if (ret) {
++ dev_err(pg_tbl->device,
++ "no memory for extended addr subtable\n");
++ return ret;
++ }
++ } else {
++ if (!gasket_is_pte_range_free(pte->sublevel +
++ subtable_slot_idx, len))
++ return -EBUSY;
++ }
++
++ remain -= len;
++ subtable_slot_idx = 0;
++ pte++;
++ slot++;
++ }
++
++ return 0;
++}
++
++/*
++ * gasket_map_extended_pages - Get and map buffers to extended addresses.
++ * If there is an error, no pages are mapped.
++ */
++static int gasket_map_extended_pages(struct gasket_page_table *pg_tbl,
++ struct sg_page_iter *sg_iter,
++ ulong host_addr, u64 dev_addr,
++ uint num_pages, u32 flags)
++{
++ int ret;
++ u64 dev_addr_end;
++ uint slot_idx, remain, len;
++ struct gasket_page_table_entry *pte;
++ u64 __iomem *slot_base;
++
++ ret = gasket_alloc_extended_entries(pg_tbl, dev_addr, num_pages);
++ if (ret) {
++ dev_addr_end = dev_addr + (num_pages / PAGE_SIZE) - 1;
++ dev_err(pg_tbl->device,
++ "page table slots (%lu,%lu) (@ 0x%llx) to (%lu,%lu) "
++ "are not available\n",
++ gasket_extended_lvl0_page_idx(pg_tbl, dev_addr),
++ gasket_extended_lvl1_page_idx(pg_tbl, dev_addr),
++ (long long unsigned int)dev_addr,
++ gasket_extended_lvl0_page_idx(pg_tbl, dev_addr_end),
++ gasket_extended_lvl1_page_idx(pg_tbl, dev_addr_end));
++ return ret;
++ }
++
++ remain = num_pages;
++ slot_idx = gasket_extended_lvl1_page_idx(pg_tbl, dev_addr);
++ pte = pg_tbl->entries + pg_tbl->num_simple_entries +
++ gasket_extended_lvl0_page_idx(pg_tbl, dev_addr);
++
++ while (remain > 0) {
++ len = min(remain, GASKET_PAGES_PER_SUBTABLE - slot_idx);
++
++ slot_base =
++ (u64 __iomem *)(page_address(pte->page) + pte->offset);
++ ret = gasket_perform_mapping(pg_tbl, pte->sublevel + slot_idx,
++ slot_base + slot_idx, sg_iter,
++ host_addr, len, flags, 0);
++ if (ret) {
++ gasket_page_table_unmap_nolock(pg_tbl, dev_addr,
++ num_pages);
++ return ret;
++ }
++
++ /*
++ * Extended page tables are in DRAM so they need to be synced
++ * each time they are updated.
++ */
++ dma_sync_single_for_device(pg_tbl->device,
++ pte->dma_addr + slot_idx * sizeof(u64),
++ len * sizeof(u64), DMA_TO_DEVICE);
++
++ remain -= len;
++ slot_idx = 0;
++ pte++;
++ if (host_addr)
++ host_addr += len * PAGE_SIZE;
++ }
++
++ return 0;
++}
++
++/*
++ * See gasket_page_table.h for general description.
++ *
++ * gasket_page_table_map calls either gasket_map_simple_pages() or
++ * gasket_map_extended_pages() to actually perform the mapping.
++ *
++ * The page table mutex is held for the entire operation.
++ */
++int gasket_page_table_map(struct gasket_page_table *pg_tbl, ulong host_addr,
++ u64 dev_addr, uint num_pages, u32 flags)
++{
++ int ret;
++
++ if (!num_pages)
++ return 0;
++
++ mutex_lock(&pg_tbl->mutex);
++
++ if (gasket_addr_is_simple(pg_tbl, dev_addr)) {
++ ret = gasket_map_simple_pages(pg_tbl, NULL, host_addr, dev_addr,
++ num_pages, flags);
++ } else {
++ ret = gasket_map_extended_pages(pg_tbl, NULL, host_addr, dev_addr,
++ num_pages, flags);
++ }
++
++ mutex_unlock(&pg_tbl->mutex);
++
++ dev_dbg(pg_tbl->device,
++ "%s done: ha %llx daddr %llx num %d, flags %x ret %d\n",
++ __func__, (unsigned long long)host_addr,
++ (unsigned long long)dev_addr, num_pages, flags, ret);
++ return ret;
++}
++EXPORT_SYMBOL(gasket_page_table_map);
++
++/*
++ * See gasket_page_table.h for general description.
++ *
++ * gasket_page_table_unmap takes the page table lock and calls either
++ * gasket_unmap_simple_pages() or gasket_unmap_extended_pages() to
++ * actually unmap the pages from device space.
++ *
++ * The page table mutex is held for the entire operation.
++ */
++void gasket_page_table_unmap(struct gasket_page_table *pg_tbl, u64 dev_addr,
++ uint num_pages)
++{
++ if (!num_pages)
++ return;
++
++ mutex_lock(&pg_tbl->mutex);
++ gasket_page_table_unmap_nolock(pg_tbl, dev_addr, num_pages);
++ mutex_unlock(&pg_tbl->mutex);
++}
++EXPORT_SYMBOL(gasket_page_table_unmap);
++
++int gasket_page_table_map_dmabuf(struct gasket_page_table *pg_tbl, int fd,
++ u64 dev_addr, uint num_pages, u32 flags)
++{
++ int ret, locked = 0;
++ struct dma_buf *dmabuf = NULL;
++ struct dma_buf_attachment *attachment = NULL;
++ struct sg_table *sgt = NULL;
++ struct sg_page_iter sg_iter;
++ struct gasket_dmabuf_mapping *mapping = NULL;
++ enum dma_data_direction direction = GET(FLAGS_DMA_DIRECTION, flags);
++
++ if (direction == DMA_NONE) {
++ dev_err(pg_tbl->device,
++ "invalid DMA direction flags=0x%x\n", flags);
++ return -EINVAL;
++ }
++
++ if (!num_pages)
++ return 0;
++
++ dmabuf = dma_buf_get(fd);
++ if (IS_ERR(dmabuf))
++ return PTR_ERR(dmabuf);
++
++ if (PAGE_ALIGN(dmabuf->size) / PAGE_SIZE < num_pages)
++ return -EINVAL;
++
++ mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
++ if (!mapping) {
++ ret = -ENOMEM;
++ goto out;
++ }
++
++ attachment = dma_buf_attach(dmabuf, pg_tbl->device);
++ if (IS_ERR(attachment)) {
++ ret = PTR_ERR(attachment);
++ goto out;
++ }
++
++ sgt = dma_buf_map_attachment(attachment, direction);
++ if (IS_ERR(sgt)) {
++ ret = PTR_ERR(sgt);
++ goto out;
++ }
++
++ mutex_lock(&pg_tbl->mutex);
++ locked = 1;
++
++ __sg_page_iter_start(&sg_iter, sgt->sgl, sgt->nents, 0);
++ if (gasket_addr_is_simple(pg_tbl, dev_addr)) {
++ ret = gasket_map_simple_pages(pg_tbl, &sg_iter, 0, dev_addr,
++ num_pages, flags);
++ } else {
++ ret = gasket_map_extended_pages(pg_tbl, &sg_iter, 0, dev_addr,
++ num_pages, flags);
++ }
++
++ if (!ret) {
++ INIT_LIST_HEAD(&mapping->list);
++ get_dma_buf(dmabuf);
++ mapping->dmabuf = dmabuf;
++ mapping->attachment = attachment;
++ mapping->sgt = sgt;
++ mapping->direction = direction;
++ list_add(&mapping->list, &pg_tbl->dmabufs);
++ sgt = NULL;
++ attachment = NULL;
++ mapping = NULL;
++ }
++
++out:
++ if (locked)
++ mutex_unlock(&pg_tbl->mutex);
++
++ if (!IS_ERR_OR_NULL(sgt))
++ dma_buf_unmap_attachment(attachment, sgt, direction);
++
++ if (!IS_ERR_OR_NULL(attachment))
++ dma_buf_detach(dmabuf, attachment);
++
++ kfree(mapping);
++ dma_buf_put(dmabuf);
++
++ return ret;
++}
++EXPORT_SYMBOL(gasket_page_table_map_dmabuf);
++
++/* Detach dmabuf from our device if attached, NULL to detach all. */
++static void gasket_page_table_detach_dmabuf_nolock(struct gasket_page_table *pg_tbl,
++ struct dma_buf *dmabuf)
++{
++ struct gasket_dmabuf_mapping *mapping, *tmp;
++
++ list_for_each_entry_safe(mapping, tmp, &pg_tbl->dmabufs, list) {
++ if (!dmabuf || mapping->dmabuf == dmabuf) {
++ dma_buf_unmap_attachment(mapping->attachment,
++ mapping->sgt,
++ mapping->direction);
++ dma_buf_detach(mapping->dmabuf, mapping->attachment);
++ dma_buf_put(mapping->dmabuf);
++ list_del(&mapping->list);
++ kfree(mapping);
++ }
++ }
++}
++
++int gasket_page_table_unmap_dmabuf(struct gasket_page_table *pg_tbl, int fd,
++ u64 dev_addr, uint num_pages)
++{
++ struct dma_buf *dmabuf;
++
++ dmabuf = dma_buf_get(fd);
++ if (IS_ERR(dmabuf))
++ return PTR_ERR(dmabuf);
++
++ if (PAGE_ALIGN(dmabuf->size) / PAGE_SIZE < num_pages) {
++ dma_buf_put(dmabuf);
++ return -EINVAL;
++ }
++
++ mutex_lock(&pg_tbl->mutex);
++
++ gasket_page_table_unmap_nolock(pg_tbl, dev_addr, num_pages);
++ gasket_page_table_detach_dmabuf_nolock(pg_tbl, dmabuf);
++
++ mutex_unlock(&pg_tbl->mutex);
++
++ dma_buf_put(dmabuf);
++
++ return 0;
++}
++EXPORT_SYMBOL(gasket_page_table_unmap_dmabuf);
++
++static void gasket_page_table_unmap_all_nolock(struct gasket_page_table *pg_tbl)
++{
++ gasket_page_table_detach_dmabuf_nolock(pg_tbl, NULL);
++
++ gasket_unmap_simple_pages(pg_tbl,
++ gasket_components_to_dev_address(pg_tbl, 1, 0,
++ 0),
++ pg_tbl->num_simple_entries);
++ gasket_unmap_extended_pages(pg_tbl,
++ gasket_components_to_dev_address(pg_tbl, 0,
++ 0, 0),
++ pg_tbl->num_extended_entries *
++ GASKET_PAGES_PER_SUBTABLE);
++}
++
++/* See gasket_page_table.h for description. */
++void gasket_page_table_unmap_all(struct gasket_page_table *pg_tbl)
++{
++ mutex_lock(&pg_tbl->mutex);
++ gasket_page_table_unmap_all_nolock(pg_tbl);
++ mutex_unlock(&pg_tbl->mutex);
++}
++EXPORT_SYMBOL(gasket_page_table_unmap_all);
++
++/* See gasket_page_table.h for description. */
++void gasket_page_table_reset(struct gasket_page_table *pg_tbl)
++{
++ mutex_lock(&pg_tbl->mutex);
++ gasket_page_table_unmap_all_nolock(pg_tbl);
++ writeq(pg_tbl->config.total_entries, pg_tbl->extended_offset_reg);
++ mutex_unlock(&pg_tbl->mutex);
++}
++
++/* See gasket_page_table.h for description. */
++int gasket_page_table_lookup_page(
++ struct gasket_page_table *pg_tbl, u64 dev_addr, struct page **ppage,
++ ulong *poffset)
++{
++ uint page_num;
++ struct gasket_page_table_entry *pte;
++
++ mutex_lock(&pg_tbl->mutex);
++ if (gasket_addr_is_simple(pg_tbl, dev_addr)) {
++ page_num = gasket_simple_page_idx(pg_tbl, dev_addr);
++ if (page_num >= pg_tbl->num_simple_entries)
++ goto fail;
++
++ pte = pg_tbl->entries + page_num;
++ if (GET(FLAGS_STATUS, pte->flags) != PTE_INUSE)
++ goto fail;
++ } else {
++ /* Find the level 0 entry, */
++ page_num = gasket_extended_lvl0_page_idx(pg_tbl, dev_addr);
++ if (page_num >= pg_tbl->num_extended_entries)
++ goto fail;
++
++ pte = pg_tbl->entries + pg_tbl->num_simple_entries + page_num;
++ if (GET(FLAGS_STATUS, pte->flags) != PTE_INUSE)
++ goto fail;
++
++ /* and its contained level 1 entry. */
++ page_num = gasket_extended_lvl1_page_idx(pg_tbl, dev_addr);
++ pte = pte->sublevel + page_num;
++ if (GET(FLAGS_STATUS, pte->flags) != PTE_INUSE)
++ goto fail;
++ }
++
++ *ppage = pte->page;
++ *poffset = pte->offset;
++ mutex_unlock(&pg_tbl->mutex);
++ return 0;
++
++fail:
++ *ppage = NULL;
++ *poffset = 0;
++ mutex_unlock(&pg_tbl->mutex);
++ return -EINVAL;
++}
++
++/* See gasket_page_table.h for description. */
++bool gasket_page_table_are_addrs_bad(
++ struct gasket_page_table *pg_tbl, ulong host_addr, u64 dev_addr,
++ ulong bytes)
++{
++ if (host_addr & (PAGE_SIZE - 1)) {
++ dev_err(pg_tbl->device,
++ "host mapping address 0x%lx must be page aligned\n",
++ host_addr);
++ return true;
++ }
++
++ return gasket_page_table_is_dev_addr_bad(pg_tbl, dev_addr, bytes);
++}
++EXPORT_SYMBOL(gasket_page_table_are_addrs_bad);
++
++/* See gasket_page_table.h for description. */
++bool gasket_page_table_is_dev_addr_bad(
++ struct gasket_page_table *pg_tbl, u64 dev_addr, ulong bytes)
++{
++ uint num_pages = bytes / PAGE_SIZE;
++
++ if (bytes & (PAGE_SIZE - 1)) {
++ dev_err(pg_tbl->device,
++ "mapping size 0x%lX must be page aligned\n", bytes);
++ return true;
++ }
++
++ if (num_pages == 0) {
++ dev_err(pg_tbl->device,
++ "requested mapping is less than one page: %lu / %lu\n",
++ bytes, PAGE_SIZE);
++ return true;
++ }
++
++ if (gasket_addr_is_simple(pg_tbl, dev_addr))
++ return gasket_is_simple_dev_addr_bad(pg_tbl, dev_addr,
++ num_pages);
++ return gasket_is_extended_dev_addr_bad(pg_tbl, dev_addr, num_pages);
++}
++EXPORT_SYMBOL(gasket_page_table_is_dev_addr_bad);
++
++/* See gasket_page_table.h for description. */
++uint gasket_page_table_max_size(struct gasket_page_table *page_table)
++{
++ if (!page_table)
++ return 0;
++ return page_table->config.total_entries;
++}
++EXPORT_SYMBOL(gasket_page_table_max_size);
++
++/* See gasket_page_table.h for description. */
++uint gasket_page_table_num_entries(struct gasket_page_table *pg_tbl)
++{
++ if (!pg_tbl)
++ return 0;
++ return pg_tbl->num_simple_entries + pg_tbl->num_extended_entries;
++}
++EXPORT_SYMBOL(gasket_page_table_num_entries);
++
++/* See gasket_page_table.h for description. */
++uint gasket_page_table_num_simple_entries(struct gasket_page_table *pg_tbl)
++{
++ if (!pg_tbl)
++ return 0;
++ return pg_tbl->num_simple_entries;
++}
++EXPORT_SYMBOL(gasket_page_table_num_simple_entries);
++
++/* See gasket_page_table.h for description. */
++uint gasket_page_table_num_active_pages(struct gasket_page_table *pg_tbl)
++{
++ if (!pg_tbl)
++ return 0;
++ return pg_tbl->num_active_pages;
++}
++EXPORT_SYMBOL(gasket_page_table_num_active_pages);
++
++/* See gasket_page_table.h */
++int gasket_page_table_system_status(struct gasket_page_table *page_table)
++{
++ if (!page_table)
++ return GASKET_STATUS_LAMED;
++
++ if (gasket_page_table_num_entries(page_table) == 0) {
++ dev_dbg(page_table->device, "Page table size is 0\n");
++ return GASKET_STATUS_LAMED;
++ }
++
++ return GASKET_STATUS_ALIVE;
++}
++
++/* Record the host_addr to coherent dma memory mapping. */
++int gasket_set_user_virt(
++ struct gasket_dev *gasket_dev, u64 size, dma_addr_t dma_address,
++ ulong vma)
++{
++ int j;
++ struct gasket_page_table *pg_tbl;
++
++ unsigned int num_pages = size / PAGE_SIZE;
++
++ /*
++ * TODO: for future chipset, better handling of the case where multiple
++ * page tables are supported on a given device
++ */
++ pg_tbl = gasket_dev->page_table[0];
++ if (!pg_tbl) {
++ dev_dbg(gasket_dev->dev, "%s: invalid page table index\n",
++ __func__);
++ return 0;
++ }
++ for (j = 0; j < num_pages; j++) {
++ pg_tbl->coherent_pages[j].user_virt =
++ (u64)vma + j * PAGE_SIZE;
++ }
++ return 0;
++}
++
++/* Allocate a block of coherent memory. */
++int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
++ dma_addr_t *dma_address, u64 index)
++{
++ dma_addr_t handle;
++ void *mem;
++ int j;
++ unsigned int num_pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
++ const struct gasket_driver_desc *driver_desc =
++ gasket_get_driver_desc(gasket_dev);
++
++ if (!gasket_dev->page_table[index])
++ return -EFAULT;
++
++ if (num_pages == 0)
++ return -EINVAL;
++
++ mem = dma_alloc_coherent(gasket_get_device(gasket_dev),
++ num_pages * PAGE_SIZE, &handle, GFP_KERNEL);
++ if (!mem)
++ goto nomem;
++
++ gasket_dev->page_table[index]->num_coherent_pages = num_pages;
++
++ /* allocate the physical memory block */
++ gasket_dev->page_table[index]->coherent_pages =
++ kcalloc(num_pages, sizeof(struct gasket_coherent_page_entry),
++ GFP_KERNEL);
++ if (!gasket_dev->page_table[index]->coherent_pages)
++ goto nomem;
++
++ gasket_dev->coherent_buffer.length_bytes =
++ PAGE_SIZE * (num_pages);
++ gasket_dev->coherent_buffer.phys_base = handle;
++ gasket_dev->coherent_buffer.virt_base = mem;
++
++ *dma_address = driver_desc->coherent_buffer_description.base;
++ for (j = 0; j < num_pages; j++) {
++ gasket_dev->page_table[index]->coherent_pages[j].paddr =
++ handle + j * PAGE_SIZE;
++ gasket_dev->page_table[index]->coherent_pages[j].kernel_virt =
++ (ulong)mem + j * PAGE_SIZE;
++ }
++
++ return 0;
++
++nomem:
++ if (mem) {
++ dma_free_coherent(gasket_get_device(gasket_dev),
++ num_pages * PAGE_SIZE, mem, handle);
++ gasket_dev->coherent_buffer.length_bytes = 0;
++ gasket_dev->coherent_buffer.virt_base = NULL;
++ gasket_dev->coherent_buffer.phys_base = 0;
++ }
++
++ kfree(gasket_dev->page_table[index]->coherent_pages);
++ gasket_dev->page_table[index]->coherent_pages = NULL;
++ gasket_dev->page_table[index]->num_coherent_pages = 0;
++ return -ENOMEM;
++}
++
++/* Free a block of coherent memory. */
++int gasket_free_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
++ dma_addr_t dma_address, u64 index)
++{
++ const struct gasket_driver_desc *driver_desc;
++
++ if (!gasket_dev->page_table[index])
++ return -EFAULT;
++
++ driver_desc = gasket_get_driver_desc(gasket_dev);
++
++ if (driver_desc->coherent_buffer_description.base != dma_address)
++ return -EADDRNOTAVAIL;
++
++ gasket_free_coherent_memory_all(gasket_dev, index);
++
++ return 0;
++}
++
++/* Release all coherent memory. */
++void gasket_free_coherent_memory_all(
++ struct gasket_dev *gasket_dev, u64 index)
++{
++ if (!gasket_dev->page_table[index])
++ return;
++
++ if (gasket_dev->coherent_buffer.length_bytes) {
++ dma_free_coherent(gasket_get_device(gasket_dev),
++ gasket_dev->coherent_buffer.length_bytes,
++ gasket_dev->coherent_buffer.virt_base,
++ gasket_dev->coherent_buffer.phys_base);
++ gasket_dev->coherent_buffer.length_bytes = 0;
++ gasket_dev->coherent_buffer.virt_base = NULL;
++ gasket_dev->coherent_buffer.phys_base = 0;
++ }
++
++ kfree(gasket_dev->page_table[index]->coherent_pages);
++ gasket_dev->page_table[index]->coherent_pages = NULL;
++ gasket_dev->page_table[index]->num_coherent_pages = 0;
++}
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_page_table.h b/drivers/staging/gasket-driver/gasket_page_table.h
+--- a/drivers/staging/gasket-driver/gasket_page_table.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_page_table.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,283 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/*
++ * Gasket Page Table functionality. This file describes the address
++ * translation/paging functionality supported by the Gasket driver framework.
++ * As much as possible, internal details are hidden to simplify use -
++ * all calls are thread-safe (protected by an internal mutex) except where
++ * indicated otherwise.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++
++#ifndef __GASKET_PAGE_TABLE_H__
++#define __GASKET_PAGE_TABLE_H__
++
++#include <linux/pci.h>
++#include <linux/types.h>
++
++#include "gasket_constants.h"
++#include "gasket_core.h"
++
++/*
++ * Structure used for managing address translation on a device. All details are
++ * internal to the implementation.
++ */
++struct gasket_page_table;
++
++/*
++ * Allocate and init address translation data.
++ * @ppage_table: Pointer to Gasket page table pointer. Set by this call.
++ * @att_base_reg: [Mapped] pointer to the first entry in the device's address
++ * translation table.
++ * @extended_offset_reg: [Mapped] pointer to the device's register containing
++ * the starting index of the extended translation table.
++ * @extended_bit_location: The index of the bit indicating whether an address
++ * is extended.
++ * @total_entries: The total number of entries in the device's address
++ * translation table.
++ * @device: Device structure for the underlying device. Only used for logging.
++ * @pci_dev: PCI system descriptor for the underlying device.
++ * whether the driver will supply its own.
++ *
++ * Description: Allocates and initializes data to track address translation -
++ * simple and extended page table metadata. Initially, the page table is
++ * partitioned such that all addresses are "simple" (single-level lookup).
++ * gasket_partition_page_table can be called to change this paritioning.
++ *
++ * Returns 0 on success, a negative error code otherwise.
++ */
++int gasket_page_table_init(struct gasket_page_table **ppg_tbl,
++ const struct gasket_bar_data *bar_data,
++ const struct gasket_page_table_config *page_table_config,
++ struct device *device, struct pci_dev *pci_dev);
++
++/*
++ * Deallocate and cleanup page table data.
++ * @page_table: Gasket page table pointer.
++ *
++ * Description: The inverse of gasket_init; frees page_table and its contained
++ * elements.
++ *
++ * Because this call destroys the page table, it cannot be
++ * thread-safe (mutex-protected)!
++ */
++void gasket_page_table_cleanup(struct gasket_page_table *page_table);
++
++/*
++ * Sets the size of the simple page table.
++ * @page_table: Gasket page table pointer.
++ * @num_simple_entries: Desired size of the simple page table (in entries).
++ *
++ * Description: gasket_partition_page_table checks to see if the simple page
++ * size can be changed (i.e., if there are no active extended
++ * mappings in the new simple size range), and, if so,
++ * sets the new simple and extended page table sizes.
++ *
++ * Returns 0 if successful, or non-zero if the page table entries
++ * are not free.
++ */
++int gasket_page_table_partition(struct gasket_page_table *page_table,
++ uint num_simple_entries);
++
++/*
++ * Get and map [host] user space pages into device memory.
++ * @page_table: Gasket page table pointer.
++ * @host_addr: Starting host virtual memory address of the pages.
++ * @dev_addr: Starting device address of the pages.
++ * @num_pages: Number of [4kB] pages to map.
++ * @flags: Specifies attributes to apply to the pages.
++ * Internal structure matches gasket_page_table_ioctl_flags.flags.
++ *
++ * Description: Maps the "num_pages" pages of host memory pointed to by
++ * host_addr to the address "dev_addr" in device memory.
++ *
++ * The caller is responsible for checking the addresses ranges.
++ *
++ * Returns 0 if successful or a non-zero error number otherwise.
++ * If there is an error, no pages are mapped.
++ */
++int gasket_page_table_map(struct gasket_page_table *page_table, ulong host_addr,
++ u64 dev_addr, uint num_pages, u32 flags);
++
++/*
++ * Map dma-buf pages into device memory.
++ * @page_table: Gasket page table pointer.
++ * @fd: Dma-buf file descriptor.
++ * @dev_addr: Starting device address of the pages.
++ * @num_pages: Number of [4kB] pages to map.
++ * @flags: Specifies attributes to apply to the pages.
++ * Internal structure matches gasket_page_table_ioctl_flags.flags.
++ *
++ * Description: Maps "num_pages" pages of dma-buf pointed to by
++ * fd to the address "dev_addr" in device memory.
++ *
++ * The caller is responsible for checking the dev_addr range.
++ *
++ * Returns 0 if successful or a non-zero error number otherwise.
++ * If there is an error, no pages are mapped.
++ */
++int gasket_page_table_map_dmabuf(struct gasket_page_table *page_table, int fd,
++ u64 dev_addr, uint num_pages, u32 flags);
++
++/*
++ * Unmap dma-buf pages from device memory.
++ * @page_table: Gasket page table pointer.
++ * @fd: Dma-buf file descriptor.
++ * @dev_addr: Starting device address of the pages.
++ * @num_pages: Number of [4kB] pages to map.
++ *
++ * Description: The inverse of gasket_page_table_map_dmabuf.
++ */
++int gasket_page_table_unmap_dmabuf(struct gasket_page_table *page_table, int fd,
++ u64 dev_addr, uint num_pages);
++
++/*
++ * Un-map host pages from device memory.
++ * @page_table: Gasket page table pointer.
++ * @dev_addr: Starting device address of the pages to unmap.
++ * @num_pages: The number of [4kB] pages to unmap.
++ *
++ * Description: The inverse of gasket_map_pages. Unmaps pages from the device.
++ */
++void gasket_page_table_unmap(struct gasket_page_table *page_table,
++ u64 dev_addr, uint num_pages);
++
++/*
++ * Unmap ALL host pages from device memory.
++ * @page_table: Gasket page table pointer.
++ */
++void gasket_page_table_unmap_all(struct gasket_page_table *page_table);
++
++/*
++ * Unmap all host pages from device memory and reset the table to fully simple
++ * addressing.
++ * @page_table: Gasket page table pointer.
++ */
++void gasket_page_table_reset(struct gasket_page_table *page_table);
++
++/*
++ * Reclaims unused page table memory.
++ * @page_table: Gasket page table pointer.
++ *
++ * Description: Examines the page table and frees any currently-unused
++ * allocations. Called internally on gasket_cleanup().
++ */
++void gasket_page_table_garbage_collect(struct gasket_page_table *page_table);
++
++/*
++ * Retrieve the backing page for a device address.
++ * @page_table: Gasket page table pointer.
++ * @dev_addr: Gasket device address.
++ * @ppage: Pointer to a page pointer for the returned page.
++ * @poffset: Pointer to an unsigned long for the returned offset.
++ *
++ * Description: Interprets the address and looks up the corresponding page
++ * in the page table and the offset in that page. (We need an
++ * offset because the host page may be larger than the Gasket chip
++ * page it contains.)
++ *
++ * Returns 0 if successful, -1 for an error. The page pointer
++ * and offset are returned through the pointers, if successful.
++ */
++int gasket_page_table_lookup_page(struct gasket_page_table *page_table,
++ u64 dev_addr, struct page **page,
++ ulong *poffset);
++
++/*
++ * Checks validity for input addrs and size.
++ * @page_table: Gasket page table pointer.
++ * @host_addr: Host address to check.
++ * @dev_addr: Gasket device address.
++ * @bytes: Size of the range to check (in bytes).
++ *
++ * Description: This call performs a number of checks to verify that the ranges
++ * specified by both addresses and the size are valid for mapping pages into
++ * device memory.
++ *
++ * Returns true if the mapping is bad, false otherwise.
++ */
++bool gasket_page_table_are_addrs_bad(struct gasket_page_table *page_table,
++ ulong host_addr, u64 dev_addr,
++ ulong bytes);
++
++/*
++ * Checks validity for input dev addr and size.
++ * @page_table: Gasket page table pointer.
++ * @dev_addr: Gasket device address.
++ * @bytes: Size of the range to check (in bytes).
++ *
++ * Description: This call performs a number of checks to verify that the range
++ * specified by the device address and the size is valid for mapping pages into
++ * device memory.
++ *
++ * Returns true if the address is bad, false otherwise.
++ */
++bool gasket_page_table_is_dev_addr_bad(struct gasket_page_table *page_table,
++ u64 dev_addr, ulong bytes);
++
++/*
++ * Gets maximum size for the given page table.
++ * @page_table: Gasket page table pointer.
++ */
++uint gasket_page_table_max_size(struct gasket_page_table *page_table);
++
++/*
++ * Gets the total number of entries in the arg.
++ * @page_table: Gasket page table pointer.
++ */
++uint gasket_page_table_num_entries(struct gasket_page_table *page_table);
++
++/*
++ * Gets the number of simple entries.
++ * @page_table: Gasket page table pointer.
++ */
++uint gasket_page_table_num_simple_entries(struct gasket_page_table *page_table);
++
++/*
++ * Gets the number of actively pinned pages.
++ * @page_table: Gasket page table pointer.
++ */
++uint gasket_page_table_num_active_pages(struct gasket_page_table *page_table);
++
++/*
++ * Get status of page table managed by @page_table.
++ * @page_table: Gasket page table pointer.
++ */
++int gasket_page_table_system_status(struct gasket_page_table *page_table);
++
++/*
++ * Allocate a block of coherent memory.
++ * @gasket_dev: Gasket Device.
++ * @size: Size of the memory block.
++ * @dma_address: Dma address allocated by the kernel.
++ * @index: Index of the gasket_page_table within this Gasket device
++ *
++ * Description: Allocate a contiguous coherent memory block, DMA'ble
++ * by this device.
++ */
++int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, uint64_t size,
++ dma_addr_t *dma_address, uint64_t index);
++/* Release a block of contiguous coherent memory, in use by a device. */
++int gasket_free_coherent_memory(struct gasket_dev *gasket_dev, uint64_t size,
++ dma_addr_t dma_address, uint64_t index);
++
++/* Release all coherent memory. */
++void gasket_free_coherent_memory_all(struct gasket_dev *gasket_dev,
++ uint64_t index);
++
++/*
++ * Records the host_addr to coherent dma memory mapping.
++ * @gasket_dev: Gasket Device.
++ * @size: Size of the virtual address range to map.
++ * @dma_address: Dma address within the coherent memory range.
++ * @vma: Virtual address we wish to map to coherent memory.
++ *
++ * Description: For each page in the virtual address range, record the
++ * coherent page mapping.
++ *
++ * Does not perform validity checking.
++ */
++int gasket_set_user_virt(struct gasket_dev *gasket_dev, uint64_t size,
++ dma_addr_t dma_address, ulong vma);
++
++#endif /* __GASKET_PAGE_TABLE_H__ */
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_sysfs.c b/drivers/staging/gasket-driver/gasket_sysfs.c
+--- a/drivers/staging/gasket-driver/gasket_sysfs.c 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_sysfs.c 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,400 @@
++// SPDX-License-Identifier: GPL-2.0
++/* Copyright (C) 2018 Google, Inc. */
++#include "gasket_sysfs.h"
++
++#include "gasket_core.h"
++
++#include <linux/device.h>
++#include <linux/printk.h>
++
++/*
++ * Pair of kernel device and user-specified pointer. Used in lookups in sysfs
++ * "show" functions to return user data.
++ */
++
++struct gasket_sysfs_mapping {
++ /*
++ * The device bound to this mapping. If this is NULL, then this mapping
++ * is free.
++ */
++ struct device *device;
++
++ /* The Gasket descriptor for this device. */
++ struct gasket_dev *gasket_dev;
++
++ /* This device's set of sysfs attributes/nodes. */
++ struct gasket_sysfs_attribute *attributes;
++
++ /* The number of live elements in "attributes". */
++ int attribute_count;
++
++ /* Protects structure from simultaneous access. */
++ struct mutex mutex;
++
++ /* Tracks active users of this mapping. */
++ struct kref refcount;
++};
++
++/*
++ * Data needed to manage users of this sysfs utility.
++ * Currently has a fixed size; if space is a concern, this can be dynamically
++ * allocated.
++ */
++/*
++ * 'Global' (file-scoped) list of mappings between devices and gasket_data
++ * pointers. This removes the requirement to have a gasket_sysfs_data
++ * handle in all files.
++ */
++static struct gasket_sysfs_mapping dev_mappings[GASKET_SYSFS_NUM_MAPPINGS];
++
++/* Callback when a mapping's refcount goes to zero. */
++static void release_entry(struct kref *ref)
++{
++ /* All work is done after the return from kref_put. */
++}
++
++/* Look up mapping information for the given device. */
++static struct gasket_sysfs_mapping *get_mapping(struct device *device)
++{
++ int i;
++
++ for (i = 0; i < GASKET_SYSFS_NUM_MAPPINGS; i++) {
++ mutex_lock(&dev_mappings[i].mutex);
++ if (dev_mappings[i].device == device) {
++ kref_get(&dev_mappings[i].refcount);
++ mutex_unlock(&dev_mappings[i].mutex);
++ return &dev_mappings[i];
++ }
++ mutex_unlock(&dev_mappings[i].mutex);
++ }
++
++ dev_dbg(device, "%s: Mapping to device %s not found\n",
++ __func__, device->kobj.name);
++ return NULL;
++}
++
++/* Put a reference to a mapping. */
++static void put_mapping(struct gasket_sysfs_mapping *mapping)
++{
++ int i;
++ int num_files_to_remove = 0;
++ struct device_attribute *files_to_remove;
++ struct device *device;
++
++ if (!mapping) {
++ pr_debug("%s: Mapping should not be NULL\n", __func__);
++ return;
++ }
++
++ mutex_lock(&mapping->mutex);
++ if (kref_put(&mapping->refcount, release_entry)) {
++ dev_dbg(mapping->device, "Removing Gasket sysfs mapping\n");
++ /*
++ * We can't remove the sysfs nodes in the kref callback, since
++ * device_remove_file() blocks until the node is free.
++ * Readers/writers of sysfs nodes, though, will be blocked on
++ * the mapping mutex, resulting in deadlock. To fix this, the
++ * sysfs nodes are removed outside the lock.
++ */
++ device = mapping->device;
++ num_files_to_remove = mapping->attribute_count;
++ files_to_remove = kcalloc(num_files_to_remove,
++ sizeof(*files_to_remove),
++ GFP_KERNEL);
++ if (files_to_remove)
++ for (i = 0; i < num_files_to_remove; i++)
++ files_to_remove[i] =
++ mapping->attributes[i].attr;
++ else
++ num_files_to_remove = 0;
++
++ kfree(mapping->attributes);
++ mapping->attributes = NULL;
++ mapping->attribute_count = 0;
++ put_device(mapping->device);
++ mapping->device = NULL;
++ mapping->gasket_dev = NULL;
++ }
++ mutex_unlock(&mapping->mutex);
++
++ if (num_files_to_remove != 0) {
++ for (i = 0; i < num_files_to_remove; ++i)
++ device_remove_file(device, &files_to_remove[i]);
++ kfree(files_to_remove);
++ }
++}
++
++/*
++ * Put a reference to a mapping N times.
++ *
++ * In higher-level resource acquire/release function pairs, the release function
++ * will need to release a mapping 2x - once for the refcount taken in the
++ * release function itself, and once for the count taken in the acquire call.
++ */
++static void put_mapping_n(struct gasket_sysfs_mapping *mapping, int times)
++{
++ int i;
++
++ for (i = 0; i < times; i++)
++ put_mapping(mapping);
++}
++
++void gasket_sysfs_init(void)
++{
++ int i;
++
++ for (i = 0; i < GASKET_SYSFS_NUM_MAPPINGS; i++) {
++ dev_mappings[i].device = NULL;
++ mutex_init(&dev_mappings[i].mutex);
++ }
++}
++
++int gasket_sysfs_create_mapping(struct device *device,
++ struct gasket_dev *gasket_dev)
++{
++ struct gasket_sysfs_mapping *mapping;
++ int map_idx = -1;
++
++ /*
++ * We need a function-level mutex to protect against the same device
++ * being added [multiple times] simultaneously.
++ */
++ static DEFINE_MUTEX(function_mutex);
++
++ mutex_lock(&function_mutex);
++ dev_dbg(device, "Creating sysfs entries for device\n");
++
++ /* Check that the device we're adding hasn't already been added. */
++ mapping = get_mapping(device);
++ if (mapping) {
++ dev_err(device,
++ "Attempting to re-initialize sysfs mapping for device\n");
++ put_mapping(mapping);
++ mutex_unlock(&function_mutex);
++ return -EBUSY;
++ }
++
++ /* Find the first empty entry in the array. */
++ for (map_idx = 0; map_idx < GASKET_SYSFS_NUM_MAPPINGS; ++map_idx) {
++ mutex_lock(&dev_mappings[map_idx].mutex);
++ if (!dev_mappings[map_idx].device)
++ /* Break with the mutex held! */
++ break;
++ mutex_unlock(&dev_mappings[map_idx].mutex);
++ }
++
++ if (map_idx == GASKET_SYSFS_NUM_MAPPINGS) {
++ dev_err(device, "All mappings have been exhausted\n");
++ mutex_unlock(&function_mutex);
++ return -ENOMEM;
++ }
++
++ dev_dbg(device, "Creating sysfs mapping for device %s\n",
++ device->kobj.name);
++
++ mapping = &dev_mappings[map_idx];
++ mapping->attributes = kcalloc(GASKET_SYSFS_MAX_NODES,
++ sizeof(*mapping->attributes),
++ GFP_KERNEL);
++ if (!mapping->attributes) {
++ dev_dbg(device, "Unable to allocate sysfs attribute array\n");
++ mutex_unlock(&mapping->mutex);
++ mutex_unlock(&function_mutex);
++ return -ENOMEM;
++ }
++
++ kref_init(&mapping->refcount);
++ mapping->device = get_device(device);
++ mapping->gasket_dev = gasket_dev;
++ mapping->attribute_count = 0;
++ mutex_unlock(&mapping->mutex);
++ mutex_unlock(&function_mutex);
++
++ /* Don't decrement the refcount here! One open count keeps it alive! */
++ return 0;
++}
++
++int gasket_sysfs_create_entries(struct device *device,
++ const struct gasket_sysfs_attribute *attrs)
++{
++ int i;
++ int ret;
++ struct gasket_sysfs_mapping *mapping = get_mapping(device);
++
++ if (!mapping) {
++ dev_dbg(device,
++ "Creating entries for device without first "
++ "initializing mapping\n");
++ return -EINVAL;
++ }
++
++ mutex_lock(&mapping->mutex);
++ for (i = 0; strcmp(attrs[i].attr.attr.name, GASKET_ARRAY_END_MARKER);
++ i++) {
++ if (mapping->attribute_count == GASKET_SYSFS_MAX_NODES) {
++ dev_err(device,
++ "Maximum number of sysfs nodes reached for "
++ "device\n");
++ mutex_unlock(&mapping->mutex);
++ put_mapping(mapping);
++ return -ENOMEM;
++ }
++
++ ret = device_create_file(device, &attrs[i].attr);
++ if (ret) {
++ dev_dbg(device, "Unable to create device entries\n");
++ mutex_unlock(&mapping->mutex);
++ put_mapping(mapping);
++ return ret;
++ }
++
++ mapping->attributes[mapping->attribute_count] = attrs[i];
++ ++mapping->attribute_count;
++ }
++
++ mutex_unlock(&mapping->mutex);
++ put_mapping(mapping);
++ return 0;
++}
++EXPORT_SYMBOL(gasket_sysfs_create_entries);
++
++void gasket_sysfs_remove_mapping(struct device *device)
++{
++ struct gasket_sysfs_mapping *mapping = get_mapping(device);
++
++ if (!mapping) {
++ dev_err(device,
++ "Attempted to remove non-existent sysfs mapping to "
++ "device\n");
++ return;
++ }
++
++ put_mapping_n(mapping, 2);
++}
++
++struct gasket_dev *gasket_sysfs_get_device_data(struct device *device)
++{
++ struct gasket_sysfs_mapping *mapping = get_mapping(device);
++
++ if (!mapping) {
++ dev_err(device, "device not registered\n");
++ return NULL;
++ }
++
++ return mapping->gasket_dev;
++}
++EXPORT_SYMBOL(gasket_sysfs_get_device_data);
++
++void gasket_sysfs_put_device_data(struct device *device, struct gasket_dev *dev)
++{
++ struct gasket_sysfs_mapping *mapping = get_mapping(device);
++
++ if (!mapping)
++ return;
++
++ /* See comment of put_mapping_n() for why the '2' is necessary. */
++ put_mapping_n(mapping, 2);
++}
++EXPORT_SYMBOL(gasket_sysfs_put_device_data);
++
++struct gasket_sysfs_attribute *
++gasket_sysfs_get_attr(struct device *device, struct device_attribute *attr)
++{
++ int i;
++ int num_attrs;
++ struct gasket_sysfs_mapping *mapping = get_mapping(device);
++ struct gasket_sysfs_attribute *attrs = NULL;
++
++ if (!mapping)
++ return NULL;
++
++ attrs = mapping->attributes;
++ num_attrs = mapping->attribute_count;
++ for (i = 0; i < num_attrs; ++i) {
++ if (!strcmp(attrs[i].attr.attr.name, attr->attr.name))
++ return &attrs[i];
++ }
++
++ dev_err(device, "Unable to find match for device_attribute %s\n",
++ attr->attr.name);
++ return NULL;
++}
++EXPORT_SYMBOL(gasket_sysfs_get_attr);
++
++void gasket_sysfs_put_attr(struct device *device,
++ struct gasket_sysfs_attribute *attr)
++{
++ int i;
++ int num_attrs;
++ struct gasket_sysfs_mapping *mapping = get_mapping(device);
++ struct gasket_sysfs_attribute *attrs = NULL;
++
++ if (!mapping)
++ return;
++
++ attrs = mapping->attributes;
++ num_attrs = mapping->attribute_count;
++ for (i = 0; i < num_attrs; ++i) {
++ if (&attrs[i] == attr) {
++ put_mapping_n(mapping, 2);
++ return;
++ }
++ }
++
++ dev_err(device, "Unable to put unknown attribute: %s\n",
++ attr->attr.attr.name);
++}
++EXPORT_SYMBOL(gasket_sysfs_put_attr);
++
++ssize_t gasket_sysfs_register_store(struct device *device,
++ struct device_attribute *attr,
++ const char *buf, size_t count)
++{
++ ulong parsed_value = 0;
++ struct gasket_sysfs_mapping *mapping;
++ struct gasket_dev *gasket_dev;
++ struct gasket_sysfs_attribute *gasket_attr;
++
++ if (count < 3 || buf[0] != '0' || buf[1] != 'x') {
++ dev_err(device,
++ "sysfs register write format: \"0x<hex value>\"\n");
++ return -EINVAL;
++ }
++
++ if (kstrtoul(buf, 16, &parsed_value) != 0) {
++ dev_err(device,
++ "Unable to parse input as 64-bit hex value: %s\n", buf);
++ return -EINVAL;
++ }
++
++ mapping = get_mapping(device);
++ if (!mapping) {
++ dev_err(device, "Device driver may have been removed\n");
++ return 0;
++ }
++
++ gasket_dev = mapping->gasket_dev;
++ if (!gasket_dev) {
++ dev_err(device, "Device driver may have been removed\n");
++ return 0;
++ }
++
++ gasket_attr = gasket_sysfs_get_attr(device, attr);
++ if (!gasket_attr) {
++ put_mapping(mapping);
++ return count;
++ }
++
++ gasket_dev_write_64(gasket_dev, parsed_value,
++ gasket_attr->data.bar_address.bar,
++ gasket_attr->data.bar_address.offset);
++
++ if (gasket_attr->write_callback)
++ gasket_attr->write_callback(gasket_dev, gasket_attr,
++ parsed_value);
++
++ gasket_sysfs_put_attr(device, gasket_attr);
++ put_mapping(mapping);
++ return count;
++}
++EXPORT_SYMBOL(gasket_sysfs_register_store);
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/gasket_sysfs.h b/drivers/staging/gasket-driver/gasket_sysfs.h
+--- a/drivers/staging/gasket-driver/gasket_sysfs.h 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/gasket_sysfs.h 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,186 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++/*
++ * Set of common sysfs utilities.
++ *
++ * Copyright (C) 2018 Google, Inc.
++ */
++
++/* The functions described here are a set of utilities to allow each file in the
++ * Gasket driver framework to manage their own set of sysfs entries, instead of
++ * centralizing all that work in one file.
++ *
++ * The goal of these utilities is to allow for sysfs entries to be easily
++ * created without causing a proliferation of sysfs "show" functions. This
++ * requires O(N) string lookups during show function execution, but as reading
++ * sysfs entries is rarely performance-critical, this is likely acceptible.
++ */
++#ifndef __GASKET_SYSFS_H__
++#define __GASKET_SYSFS_H__
++
++#include "gasket_constants.h"
++#include "gasket_core.h"
++#include <linux/device.h>
++#include <linux/stringify.h>
++#include <linux/sysfs.h>
++
++/* The maximum number of mappings/devices a driver needs to support. */
++#define GASKET_SYSFS_NUM_MAPPINGS (GASKET_FRAMEWORK_DESC_MAX * GASKET_DEV_MAX)
++
++/* The maximum number of sysfs nodes in a directory.
++ */
++#define GASKET_SYSFS_MAX_NODES 196
++
++/* End markers for sysfs struct arrays. */
++#define GASKET_ARRAY_END_TOKEN GASKET_RESERVED_ARRAY_END
++#define GASKET_ARRAY_END_MARKER __stringify(GASKET_ARRAY_END_TOKEN)
++
++/*
++ * Terminator struct for a gasket_sysfs_attr array. Must be at the end of
++ * all gasket_sysfs_attribute arrays.
++ */
++#define GASKET_END_OF_ATTR_ARRAY \
++ { \
++ .attr = __ATTR(GASKET_ARRAY_END_TOKEN, S_IRUGO, NULL, NULL), \
++ .data.attr_type = 0, \
++ }
++
++/*
++ * Pairing of sysfs attribute and user data.
++ * Used in lookups in sysfs "show" functions to return attribute metadata.
++ */
++struct gasket_sysfs_attribute {
++ /* The underlying sysfs device attribute associated with this data. */
++ struct device_attribute attr;
++
++ /* User-specified data to associate with the attribute. */
++ union {
++ struct bar_address_ {
++ ulong bar;
++ ulong offset;
++ } bar_address;
++ uint attr_type;
++ } data;
++
++ /*
++ * Function pointer to a callback to be invoked when this attribute is
++ * written (if so configured). The arguments are to the Gasket device
++ * pointer, the enclosing gasket_attr structure, and the value written.
++ * The callback should perform any logging necessary, as errors cannot
++ * be returned from the callback.
++ */
++ void (*write_callback)(struct gasket_dev *dev,
++ struct gasket_sysfs_attribute *attr,
++ ulong value);
++};
++
++#define GASKET_SYSFS_RO(_name, _show_function, _attr_type) \
++ { \
++ .attr = __ATTR(_name, S_IRUGO, _show_function, NULL), \
++ .data.attr_type = _attr_type \
++ }
++
++#define GASKET_SYSFS_RW(_name, _show_function, _store_function, _attr_type) \
++ { \
++ .attr = __ATTR(_name, S_IWUSR | S_IWGRP | S_IRUGO, \
++ _show_function, _store_function), \
++ .data.attr_type = _attr_type \
++ }
++
++/* Initializes the Gasket sysfs subsystem.
++ *
++ * Description: Performs one-time initialization. Must be called before usage
++ * at [Gasket] module load time.
++ */
++void gasket_sysfs_init(void);
++
++/*
++ * Create an entry in mapping_data between a device and a Gasket device.
++ * @device: Device struct to map to.
++ * @gasket_dev: The dev struct associated with the driver controlling @device.
++ *
++ * Description: This function maps a gasket_dev* to a device*. This mapping can
++ * be used in sysfs_show functions to get a handle to the gasket_dev struct
++ * controlling the device node.
++ *
++ * If this function is not called before gasket_sysfs_create_entries, a warning
++ * will be logged.
++ */
++int gasket_sysfs_create_mapping(struct device *device,
++ struct gasket_dev *gasket_dev);
++
++/*
++ * Creates bulk entries in sysfs.
++ * @device: Kernel device structure.
++ * @attrs: List of attributes/sysfs entries to create.
++ *
++ * Description: Creates each sysfs entry described in "attrs". Can be called
++ * multiple times for a given @device. If the gasket_dev specified in
++ * gasket_sysfs_create_mapping had a legacy device, the entries will be created
++ * for it, as well.
++ */
++int gasket_sysfs_create_entries(struct device *device,
++ const struct gasket_sysfs_attribute *attrs);
++
++/*
++ * Removes a device mapping from the global table.
++ * @device: Device to unmap.
++ *
++ * Description: Removes the device->Gasket device mapping from the internal
++ * table.
++ */
++void gasket_sysfs_remove_mapping(struct device *device);
++
++/*
++ * User data lookup based on kernel device structure.
++ * @device: Kernel device structure.
++ *
++ * Description: Returns the user data associated with "device" in a prior call
++ * to gasket_sysfs_create_entries. Returns NULL if no mapping can be found.
++ * Upon success, this call take a reference to internal sysfs data that must be
++ * released with gasket_sysfs_put_device_data. While this reference is held, the
++ * underlying device sysfs information/structure will remain valid/will not be
++ * deleted.
++ */
++struct gasket_dev *gasket_sysfs_get_device_data(struct device *device);
++
++/*
++ * Releases a references to internal data.
++ * @device: Kernel device structure.
++ * @dev: Gasket device descriptor (returned by gasket_sysfs_get_device_data).
++ */
++void gasket_sysfs_put_device_data(struct device *device,
++ struct gasket_dev *gasket_dev);
++
++/*
++ * Gasket-specific attribute lookup.
++ * @device: Kernel device structure.
++ * @attr: Device attribute to look up.
++ *
++ * Returns the Gasket sysfs attribute associated with the kernel device
++ * attribute and device structure itself. Upon success, this call will take a
++ * reference to internal sysfs data that must be released with a call to
++ * gasket_sysfs_put_attr. While this reference is held, the underlying device
++ * sysfs information/structure will remain valid/will not be deleted.
++ */
++struct gasket_sysfs_attribute *
++gasket_sysfs_get_attr(struct device *device, struct device_attribute *attr);
++
++/*
++ * Releases a references to internal data.
++ * @device: Kernel device structure.
++ * @attr: Gasket sysfs attribute descriptor (returned by
++ * gasket_sysfs_get_attr).
++ */
++void gasket_sysfs_put_attr(struct device *device,
++ struct gasket_sysfs_attribute *attr);
++
++/*
++ * Write to a register sysfs node.
++ * @buf: NULL-terminated data being written.
++ * @count: number of bytes in the "buf" argument.
++ */
++ssize_t gasket_sysfs_register_store(struct device *device,
++ struct device_attribute *attr,
++ const char *buf, size_t count);
++
++#endif /* __GASKET_SYSFS_H__ */
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/Kconfig b/drivers/staging/gasket-driver/Kconfig
+--- a/drivers/staging/gasket-driver/Kconfig 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/Kconfig 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,24 @@
++menu "Gasket devices"
++
++config STAGING_GASKET_FRAMEWORK
++ tristate "Gasket framework"
++ depends on PCI && (X86_64 || ARM64)
++ help
++ This framework supports Gasket-compatible devices, such as Apex.
++ It is required for any of the following module(s).
++
++ To compile this driver as a module, choose M here. The module
++ will be called "gasket".
++
++config STAGING_APEX_DRIVER
++ tristate "Apex Driver"
++ depends on STAGING_GASKET_FRAMEWORK
++ help
++ This driver supports the Apex Edge TPU device. See
++ https://cloud.google.com/edge-tpu/ for more information.
++ Say Y if you want to include this driver in the kernel.
++
++ To compile this driver as a module, choose M here. The module
++ will be called "apex".
++
++endmenu
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/Makefile b/drivers/staging/gasket-driver/Makefile
+--- a/drivers/staging/gasket-driver/Makefile 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/Makefile 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,17 @@
++#
++# Makefile for Gasket framework and dependent drivers.
++#
++
++obj-m += gasket.o
++obj-m += apex.o
++
++gasket-objs := gasket_core.o gasket_ioctl.o gasket_interrupt.o gasket_page_table.o gasket_sysfs.o
++apex-objs := apex_driver.o
++
++KVERSION := $(shell uname -r)
++
++all:
++ $(MAKE) -C /lib/modules/$(KVERSION)/build M=$(PWD) modules
++
++clean:
++ $(MAKE) -C /lib/modules/$(KVERSION)/build M=$(PWD) clean
+diff '--color=auto' -urN a/drivers/staging/gasket-driver/TODO b/drivers/staging/gasket-driver/TODO
+--- a/drivers/staging/gasket-driver/TODO 1970-01-01 01:00:00.000000000 +0100
++++ b/drivers/staging/gasket-driver/TODO 2025-02-19 19:25:02.480079055 +0000
+@@ -0,0 +1,9 @@
++This is a list of things that need to be done to get this driver out of the
++staging directory.
++- Document sysfs files with Documentation/ABI/ entries.
++- Use misc interface instead of major number for driver version description.
++- Add descriptions of module_param's
++- apex_get_status() should actually check status.
++- "drivers" should never be dealing with "raw" sysfs calls or mess around with
++ kobjects at all. The driver core should handle all of this for you
++ automaically. There should not be a need for raw attribute macros.
+diff '--color=auto' -urN a/drivers/staging/Kconfig b/drivers/staging/Kconfig
+--- a/drivers/staging/Kconfig 2025-02-18 23:57:39.206607973 +0000
++++ b/drivers/staging/Kconfig 2025-02-19 19:25:43.186155250 +0000
+@@ -50,4 +50,6 @@
+
+ source "drivers/staging/gpib/Kconfig"
+
++source "drivers/staging/gasket-driver/Kconfig"
++
+ endif # STAGING
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