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linux_dsm_epyc7002/drivers/pci/iov.c
Chris Wright 6faf17f6f1 PCI SR-IOV: correct broken resource alignment calculations 
An SR-IOV capable device includes an SR-IOV PCIe capability which
describes the Virtual Function (VF) BAR requirements.  A typical SR-IOV
device can support multiple VFs whose BARs must be in a contiguous region,
effectively an array of VF BARs.  The BAR reports the size requirement
for a single VF.  We calculate the full range needed by simply multiplying
the VF BAR size with the number of possible VFs and create a resource
spanning the full range.

This all seems sane enough except it artificially inflates the alignment
requirement for the VF BAR.  The VF BAR need only be aligned to the size
of a single BAR not the contiguous range of VF BARs.  This can cause us
to fail to allocate resources for the BAR despite the fact that we
actually have enough space.

This patch adds a thin PCI specific layer over the generic
resource_alignment() function which is aware of the special nature of
VF BARs and does sorting and allocation based on the smaller alignment
requirement.

I recognize that while resource_alignment is generic, it's basically a
PCI helper.  An alternative to this patch is to add PCI VF BAR specific
information to struct resource.  I opted for the extra layer rather than
adding such PCI specific information to struct resource.  This does
have the slight downside that we don't cache the BAR size and re-read
for each alignment query (happens a small handful of times during boot
for each VF BAR).

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Yu Zhao <yu.zhao@intel.com>
Cc: stable@kernel.org
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-08-30 08:37:25 -07:00

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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/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 (!dev->is_pcie)
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);
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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