blob: a445d58fb39998b6f7ee067b91645233bdaa1fda [file] [log] [blame]
// 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/printk.h>
#include <linux/sched.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
};
/* 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_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);
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_nocache(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(64));
dma_set_coherent_mask(&gasket_dev->pci_dev->dev, DMA_BIT_MASK(64));
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;
/* 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;
}
/*
* 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,
&region_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);
ret = remap_pfn_range(vma, vma->vm_start,
(gasket_dev->coherent_buffer.phys_base) >>
PAGE_SHIFT, requested_length, vma->vm_page_prot);
if (ret) {
dev_err(gasket_dev->dev, "Error remapping PFN range 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,
};
/* 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;
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);
/**
* 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);
internal->class =
class_create(driver_desc->module, driver_desc->name);
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);