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linux/drivers/pci/iov.c

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/*
* drivers/pci/iov.c
*
* Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
*
* PCI Express I/O Virtualization (IOV) support.
* Single Root IOV 1.0
* Address Translation Service 1.0
*/
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/delay.h>
#include "pci.h"
#define VIRTFN_ID_LEN 16
static inline u8 virtfn_bus(struct pci_dev *dev, int id)
{
return dev->bus->number + ((dev->devfn + dev->sriov->offset +
dev->sriov->stride * id) >> 8);
}
static inline u8 virtfn_devfn(struct pci_dev *dev, int id)
{
return (dev->devfn + dev->sriov->offset +
dev->sriov->stride * id) & 0xff;
}
static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
{
int rc;
struct pci_bus *child;
if (bus->number == busnr)
return bus;
child = pci_find_bus(pci_domain_nr(bus), busnr);
if (child)
return child;
child = pci_add_new_bus(bus, NULL, busnr);
if (!child)
return NULL;
child->subordinate = busnr;
child->dev.parent = bus->bridge;
rc = pci_bus_add_child(child);
if (rc) {
pci_remove_bus(child);
return NULL;
}
return child;
}
static void virtfn_remove_bus(struct pci_bus *bus, int busnr)
{
struct pci_bus *child;
if (bus->number == busnr)
return;
child = pci_find_bus(pci_domain_nr(bus), busnr);
BUG_ON(!child);
if (list_empty(&child->devices))
pci_remove_bus(child);
}
static int virtfn_add(struct pci_dev *dev, int id, int reset)
{
int i;
int rc;
u64 size;
char buf[VIRTFN_ID_LEN];
struct pci_dev *virtfn;
struct resource *res;
struct pci_sriov *iov = dev->sriov;
virtfn = alloc_pci_dev();
if (!virtfn)
return -ENOMEM;
mutex_lock(&iov->dev->sriov->lock);
virtfn->bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
if (!virtfn->bus) {
kfree(virtfn);
mutex_unlock(&iov->dev->sriov->lock);
return -ENOMEM;
}
virtfn->devfn = virtfn_devfn(dev, id);
virtfn->vendor = dev->vendor;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
pci_setup_device(virtfn);
virtfn->dev.parent = dev->dev.parent;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = dev->resource + PCI_IOV_RESOURCES + i;
if (!res->parent)
continue;
virtfn->resource[i].name = pci_name(virtfn);
virtfn->resource[i].flags = res->flags;
size = resource_size(res);
do_div(size, iov->total);
virtfn->resource[i].start = res->start + size * id;
virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
rc = request_resource(res, &virtfn->resource[i]);
BUG_ON(rc);
}
if (reset)
__pci_reset_function(virtfn);
pci_device_add(virtfn, virtfn->bus);
mutex_unlock(&iov->dev->sriov->lock);
virtfn->physfn = pci_dev_get(dev);
virtfn->is_virtfn = 1;
rc = pci_bus_add_device(virtfn);
if (rc)
goto failed1;
sprintf(buf, "virtfn%u", id);
rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
if (rc)
goto failed1;
rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
if (rc)
goto failed2;
kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
return 0;
failed2:
sysfs_remove_link(&dev->dev.kobj, buf);
failed1:
pci_dev_put(dev);
mutex_lock(&iov->dev->sriov->lock);
pci_remove_bus_device(virtfn);
virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
mutex_unlock(&iov->dev->sriov->lock);
return rc;
}
static void virtfn_remove(struct pci_dev *dev, int id, int reset)
{
char buf[VIRTFN_ID_LEN];
struct pci_bus *bus;
struct pci_dev *virtfn;
struct pci_sriov *iov = dev->sriov;
bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id));
if (!bus)
return;
virtfn = pci_get_slot(bus, virtfn_devfn(dev, id));
if (!virtfn)
return;
pci_dev_put(virtfn);
if (reset) {
device_release_driver(&virtfn->dev);
__pci_reset_function(virtfn);
}
sprintf(buf, "virtfn%u", id);
sysfs_remove_link(&dev->dev.kobj, buf);
sysfs_remove_link(&virtfn->dev.kobj, "physfn");
mutex_lock(&iov->dev->sriov->lock);
pci_remove_bus_device(virtfn);
virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
mutex_unlock(&iov->dev->sriov->lock);
pci_dev_put(dev);
}
static int sriov_migration(struct pci_dev *dev)
{
u16 status;
struct pci_sriov *iov = dev->sriov;
if (!iov->nr_virtfn)
return 0;
if (!(iov->cap & PCI_SRIOV_CAP_VFM))
return 0;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_STATUS, &status);
if (!(status & PCI_SRIOV_STATUS_VFM))
return 0;
schedule_work(&iov->mtask);
return 1;
}
static void sriov_migration_task(struct work_struct *work)
{
int i;
u8 state;
u16 status;
struct pci_sriov *iov = container_of(work, struct pci_sriov, mtask);
for (i = iov->initial; i < iov->nr_virtfn; i++) {
state = readb(iov->mstate + i);
if (state == PCI_SRIOV_VFM_MI) {
writeb(PCI_SRIOV_VFM_AV, iov->mstate + i);
state = readb(iov->mstate + i);
if (state == PCI_SRIOV_VFM_AV)
virtfn_add(iov->self, i, 1);
} else if (state == PCI_SRIOV_VFM_MO) {
virtfn_remove(iov->self, i, 1);
writeb(PCI_SRIOV_VFM_UA, iov->mstate + i);
state = readb(iov->mstate + i);
if (state == PCI_SRIOV_VFM_AV)
virtfn_add(iov->self, i, 0);
}
}
pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);
status &= ~PCI_SRIOV_STATUS_VFM;
pci_write_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, status);
}
static int sriov_enable_migration(struct pci_dev *dev, int nr_virtfn)
{
int bir;
u32 table;
resource_size_t pa;
struct pci_sriov *iov = dev->sriov;
if (nr_virtfn <= iov->initial)
return 0;
pci_read_config_dword(dev, iov->pos + PCI_SRIOV_VFM, &table);
bir = PCI_SRIOV_VFM_BIR(table);
if (bir > PCI_STD_RESOURCE_END)
return -EIO;
table = PCI_SRIOV_VFM_OFFSET(table);
if (table + nr_virtfn > pci_resource_len(dev, bir))
return -EIO;
pa = pci_resource_start(dev, bir) + table;
iov->mstate = ioremap(pa, nr_virtfn);
if (!iov->mstate)
return -ENOMEM;
INIT_WORK(&iov->mtask, sriov_migration_task);
iov->ctrl |= PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR;
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
return 0;
}
static void sriov_disable_migration(struct pci_dev *dev)
{
struct pci_sriov *iov = dev->sriov;
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
cancel_work_sync(&iov->mtask);
iounmap(iov->mstate);
}
static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
{
int rc;
int i, j;
int nres;
u16 offset, stride, initial;
struct resource *res;
struct pci_dev *pdev;
struct pci_sriov *iov = dev->sriov;
if (!nr_virtfn)
return 0;
if (iov->nr_virtfn)
return -EINVAL;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
if (initial > iov->total ||
(!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total)))
return -EIO;
if (nr_virtfn < 0 || nr_virtfn > iov->total ||
(!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
return -EINVAL;
pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &offset);
pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &stride);
if (!offset || (nr_virtfn > 1 && !stride))
return -EIO;
nres = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = dev->resource + PCI_IOV_RESOURCES + i;
if (res->parent)
nres++;
}
if (nres != iov->nres) {
dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
return -ENOMEM;
}
iov->offset = offset;
iov->stride = stride;
if (virtfn_bus(dev, nr_virtfn - 1) > dev->bus->subordinate) {
dev_err(&dev->dev, "SR-IOV: bus number out of range\n");
return -ENOMEM;
}
if (iov->link != dev->devfn) {
pdev = pci_get_slot(dev->bus, iov->link);
if (!pdev)
return -ENODEV;
pci_dev_put(pdev);
if (!pdev->is_physfn)
return -ENODEV;
rc = sysfs_create_link(&dev->dev.kobj,
&pdev->dev.kobj, "dep_link");
if (rc)
return rc;
}
iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
pci_block_user_cfg_access(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
msleep(100);
pci_unblock_user_cfg_access(dev);
iov->initial = initial;
if (nr_virtfn < initial)
initial = nr_virtfn;
for (i = 0; i < initial; i++) {
rc = virtfn_add(dev, i, 0);
if (rc)
goto failed;
}
if (iov->cap & PCI_SRIOV_CAP_VFM) {
rc = sriov_enable_migration(dev, nr_virtfn);
if (rc)
goto failed;
}
kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
iov->nr_virtfn = nr_virtfn;
return 0;
failed:
for (j = 0; j < i; j++)
virtfn_remove(dev, j, 0);
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
pci_block_user_cfg_access(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
ssleep(1);
pci_unblock_user_cfg_access(dev);
if (iov->link != dev->devfn)
sysfs_remove_link(&dev->dev.kobj, "dep_link");
return rc;
}
static void sriov_disable(struct pci_dev *dev)
{
int i;
struct pci_sriov *iov = dev->sriov;
if (!iov->nr_virtfn)
return;
if (iov->cap & PCI_SRIOV_CAP_VFM)
sriov_disable_migration(dev);
for (i = 0; i < iov->nr_virtfn; i++)
virtfn_remove(dev, i, 0);
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
pci_block_user_cfg_access(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
ssleep(1);
pci_unblock_user_cfg_access(dev);
if (iov->link != dev->devfn)
sysfs_remove_link(&dev->dev.kobj, "dep_link");
iov->nr_virtfn = 0;
}
static int sriov_init(struct pci_dev *dev, int pos)
{
int i;
int rc;
int nres;
u32 pgsz;
u16 ctrl, total, offset, stride;
struct pci_sriov *iov;
struct resource *res;
struct pci_dev *pdev;
if (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
dev->pcie_type != PCI_EXP_TYPE_ENDPOINT)
return -ENODEV;
pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
if (ctrl & PCI_SRIOV_CTRL_VFE) {
pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
ssleep(1);
}
pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
if (!total)
return 0;
ctrl = 0;
list_for_each_entry(pdev, &dev->bus->devices, bus_list)
if (pdev->is_physfn)
goto found;
pdev = NULL;
if (pci_ari_enabled(dev->bus))
ctrl |= PCI_SRIOV_CTRL_ARI;
found:
pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, total);
pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
if (!offset || (total > 1 && !stride))
return -EIO;
pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
pgsz &= ~((1 << i) - 1);
if (!pgsz)
return -EIO;
pgsz &= ~(pgsz - 1);
pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
nres = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = dev->resource + PCI_IOV_RESOURCES + i;
i += __pci_read_base(dev, pci_bar_unknown, res,
pos + PCI_SRIOV_BAR + i * 4);
if (!res->flags)
continue;
if (resource_size(res) & (PAGE_SIZE - 1)) {
rc = -EIO;
goto failed;
}
res->end = res->start + resource_size(res) * total - 1;
nres++;
}
iov = kzalloc(sizeof(*iov), GFP_KERNEL);
if (!iov) {
rc = -ENOMEM;
goto failed;
}
iov->pos = pos;
iov->nres = nres;
iov->ctrl = ctrl;
iov->total = total;
iov->offset = offset;
iov->stride = stride;
iov->pgsz = pgsz;
iov->self = dev;
pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
if (dev->pcie_type == PCI_EXP_TYPE_RC_END)
iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
if (pdev)
iov->dev = pci_dev_get(pdev);
else
iov->dev = dev;
mutex_init(&iov->lock);
dev->sriov = iov;
dev->is_physfn = 1;
return 0;
failed:
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = dev->resource + PCI_IOV_RESOURCES + i;
res->flags = 0;
}
return rc;
}
static void sriov_release(struct pci_dev *dev)
{
BUG_ON(dev->sriov->nr_virtfn);
if (dev != dev->sriov->dev)
pci_dev_put(dev->sriov->dev);
mutex_destroy(&dev->sriov->lock);
kfree(dev->sriov);
dev->sriov = NULL;
}
static void sriov_restore_state(struct pci_dev *dev)
{
int i;
u16 ctrl;
struct pci_sriov *iov = dev->sriov;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
if (ctrl & PCI_SRIOV_CTRL_VFE)
return;
for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
pci_update_resource(dev, i);
pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, iov->nr_virtfn);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
msleep(100);
}
/**
* pci_iov_init - initialize the IOV capability
* @dev: the PCI device
*
* Returns 0 on success, or negative on failure.
*/
int pci_iov_init(struct pci_dev *dev)
{
int pos;
if (!pci_is_pcie(dev))
return -ENODEV;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
if (pos)
return sriov_init(dev, pos);
return -ENODEV;
}
/**
* pci_iov_release - release resources used by the IOV capability
* @dev: the PCI device
*/
void pci_iov_release(struct pci_dev *dev)
{
if (dev->is_physfn)
sriov_release(dev);
}
/**
* pci_iov_resource_bar - get position of the SR-IOV BAR
* @dev: the PCI device
* @resno: the resource number
* @type: the BAR type to be filled in
*
* Returns position of the BAR encapsulated in the SR-IOV capability.
*/
int pci_iov_resource_bar(struct pci_dev *dev, int resno,
enum pci_bar_type *type)
{
if (resno < PCI_IOV_RESOURCES || resno > PCI_IOV_RESOURCE_END)
return 0;
BUG_ON(!dev->is_physfn);
*type = pci_bar_unknown;
return dev->sriov->pos + PCI_SRIOV_BAR +
4 * (resno - PCI_IOV_RESOURCES);
}
/**
* pci_sriov_resource_alignment - get resource alignment for VF BAR
* @dev: the PCI device
* @resno: the resource number
*
* Returns the alignment of the VF BAR found in the SR-IOV capability.
* This is not the same as the resource size which is defined as
* the VF BAR size multiplied by the number of VFs. The alignment
* is just the VF BAR size.
*/
int pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
{
struct resource tmp;
enum pci_bar_type type;
int reg = pci_iov_resource_bar(dev, resno, &type);
if (!reg)
return 0;
__pci_read_base(dev, type, &tmp, reg);
return resource_alignment(&tmp);
}
/**
* pci_restore_iov_state - restore the state of the IOV capability
* @dev: the PCI device
*/
void pci_restore_iov_state(struct pci_dev *dev)
{
if (dev->is_physfn)
sriov_restore_state(dev);
}
/**
* pci_iov_bus_range - find bus range used by Virtual Function
* @bus: the PCI bus
*
* Returns max number of buses (exclude current one) used by Virtual
* Functions.
*/
int pci_iov_bus_range(struct pci_bus *bus)
{
int max = 0;
u8 busnr;
struct pci_dev *dev;
list_for_each_entry(dev, &bus->devices, bus_list) {
if (!dev->is_physfn)
continue;
busnr = virtfn_bus(dev, dev->sriov->total - 1);
if (busnr > max)
max = busnr;
}
return max ? max - bus->number : 0;
}
/**
* pci_enable_sriov - enable the SR-IOV capability
* @dev: the PCI device
* @nr_virtfn: number of virtual functions to enable
*
* Returns 0 on success, or negative on failure.
*/
int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
{
might_sleep();
if (!dev->is_physfn)
return -ENODEV;
return sriov_enable(dev, nr_virtfn);
}
EXPORT_SYMBOL_GPL(pci_enable_sriov);
/**
* pci_disable_sriov - disable the SR-IOV capability
* @dev: the PCI device
*/
void pci_disable_sriov(struct pci_dev *dev)
{
might_sleep();
if (!dev->is_physfn)
return;
sriov_disable(dev);
}
EXPORT_SYMBOL_GPL(pci_disable_sriov);
/**
* pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
* @dev: the PCI device
*
* Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
*
* Physical Function driver is responsible to register IRQ handler using
* VF Migration Interrupt Message Number, and call this function when the
* interrupt is generated by the hardware.
*/
irqreturn_t pci_sriov_migration(struct pci_dev *dev)
{
if (!dev->is_physfn)
return IRQ_NONE;
return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
}
EXPORT_SYMBOL_GPL(pci_sriov_migration);
/**
* pci_num_vf - return number of VFs associated with a PF device_release_driver
* @dev: the PCI device
*
* Returns number of VFs, or 0 if SR-IOV is not enabled.
*/
int pci_num_vf(struct pci_dev *dev)
{
if (!dev || !dev->is_physfn)
return 0;
else
return dev->sriov->nr_virtfn;
}
EXPORT_SYMBOL_GPL(pci_num_vf);
static int ats_alloc_one(struct pci_dev *dev, int ps)
{
int pos;
u16 cap;
struct pci_ats *ats;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
if (!pos)
return -ENODEV;
ats = kzalloc(sizeof(*ats), GFP_KERNEL);
if (!ats)
return -ENOMEM;
ats->pos = pos;
ats->stu = ps;
pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
PCI_ATS_MAX_QDEP;
dev->ats = ats;
return 0;
}
static void ats_free_one(struct pci_dev *dev)
{
kfree(dev->ats);
dev->ats = NULL;
}
/**
* pci_enable_ats - enable the ATS capability
* @dev: the PCI device
* @ps: the IOMMU page shift
*
* Returns 0 on success, or negative on failure.
*/
int pci_enable_ats(struct pci_dev *dev, int ps)
{
int rc;
u16 ctrl;
BUG_ON(dev->ats && dev->ats->is_enabled);
if (ps < PCI_ATS_MIN_STU)
return -EINVAL;
if (dev->is_physfn || dev->is_virtfn) {
struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
mutex_lock(&pdev->sriov->lock);
if (pdev->ats)
rc = pdev->ats->stu == ps ? 0 : -EINVAL;
else
rc = ats_alloc_one(pdev, ps);
if (!rc)
pdev->ats->ref_cnt++;
mutex_unlock(&pdev->sriov->lock);
if (rc)
return rc;
}
if (!dev->is_physfn) {
rc = ats_alloc_one(dev, ps);
if (rc)
return rc;
}
ctrl = PCI_ATS_CTRL_ENABLE;
if (!dev->is_virtfn)
ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
dev->ats->is_enabled = 1;
return 0;
}
/**
* pci_disable_ats - disable the ATS capability
* @dev: the PCI device
*/
void pci_disable_ats(struct pci_dev *dev)
{
u16 ctrl;
BUG_ON(!dev->ats || !dev->ats->is_enabled);
pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
ctrl &= ~PCI_ATS_CTRL_ENABLE;
pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
dev->ats->is_enabled = 0;
if (dev->is_physfn || dev->is_virtfn) {
struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
mutex_lock(&pdev->sriov->lock);
pdev->ats->ref_cnt--;
if (!pdev->ats->ref_cnt)
ats_free_one(pdev);
mutex_unlock(&pdev->sriov->lock);
}
if (!dev->is_physfn)
ats_free_one(dev);
}
/**
* pci_ats_queue_depth - query the ATS Invalidate Queue Depth
* @dev: the PCI device
*
* Returns the queue depth on success, or negative on failure.
*
* The ATS spec uses 0 in the Invalidate Queue Depth field to
* indicate that the function can accept 32 Invalidate Request.
* But here we use the `real' values (i.e. 1~32) for the Queue
* Depth; and 0 indicates the function shares the Queue with
* other functions (doesn't exclusively own a Queue).
*/
int pci_ats_queue_depth(struct pci_dev *dev)
{
int pos;
u16 cap;
if (dev->is_virtfn)
return 0;
if (dev->ats)
return dev->ats->qdep;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
if (!pos)
return -ENODEV;
pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
PCI_ATS_MAX_QDEP;
}
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