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OpenCloudOS-Kernel/drivers/pci/access.c

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#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/wait.h>
#include "pci.h"
/*
* This interrupt-safe spinlock protects all accesses to PCI
* configuration space.
*/
DEFINE_RAW_SPINLOCK(pci_lock);
/*
* Wrappers for all PCI configuration access functions. They just check
* alignment, do locking and call the low-level functions pointed to
* by pci_dev->ops.
*/
#define PCI_byte_BAD 0
#define PCI_word_BAD (pos & 1)
#define PCI_dword_BAD (pos & 3)
#define PCI_OP_READ(size, type, len) \
int pci_bus_read_config_##size \
(struct pci_bus *bus, unsigned int devfn, int pos, type *value) \
{ \
int res; \
unsigned long flags; \
u32 data = 0; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
raw_spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->read(bus, devfn, pos, len, &data); \
*value = (type)data; \
raw_spin_unlock_irqrestore(&pci_lock, flags); \
return res; \
}
#define PCI_OP_WRITE(size, type, len) \
int pci_bus_write_config_##size \
(struct pci_bus *bus, unsigned int devfn, int pos, type value) \
{ \
int res; \
unsigned long flags; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
raw_spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->write(bus, devfn, pos, len, value); \
raw_spin_unlock_irqrestore(&pci_lock, flags); \
return res; \
}
PCI_OP_READ(byte, u8, 1)
PCI_OP_READ(word, u16, 2)
PCI_OP_READ(dword, u32, 4)
PCI_OP_WRITE(byte, u8, 1)
PCI_OP_WRITE(word, u16, 2)
PCI_OP_WRITE(dword, u32, 4)
EXPORT_SYMBOL(pci_bus_read_config_byte);
EXPORT_SYMBOL(pci_bus_read_config_word);
EXPORT_SYMBOL(pci_bus_read_config_dword);
EXPORT_SYMBOL(pci_bus_write_config_byte);
EXPORT_SYMBOL(pci_bus_write_config_word);
EXPORT_SYMBOL(pci_bus_write_config_dword);
int pci_generic_config_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
void __iomem *addr;
addr = bus->ops->map_bus(bus, devfn, where);
if (!addr) {
*val = ~0;
return PCIBIOS_DEVICE_NOT_FOUND;
}
if (size == 1)
*val = readb(addr);
else if (size == 2)
*val = readw(addr);
else
*val = readl(addr);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_read);
int pci_generic_config_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
void __iomem *addr;
addr = bus->ops->map_bus(bus, devfn, where);
if (!addr)
return PCIBIOS_DEVICE_NOT_FOUND;
if (size == 1)
writeb(val, addr);
else if (size == 2)
writew(val, addr);
else
writel(val, addr);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_write);
int pci_generic_config_read32(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
void __iomem *addr;
addr = bus->ops->map_bus(bus, devfn, where & ~0x3);
if (!addr) {
*val = ~0;
return PCIBIOS_DEVICE_NOT_FOUND;
}
*val = readl(addr);
if (size <= 2)
*val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_read32);
int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
void __iomem *addr;
u32 mask, tmp;
addr = bus->ops->map_bus(bus, devfn, where & ~0x3);
if (!addr)
return PCIBIOS_DEVICE_NOT_FOUND;
if (size == 4) {
writel(val, addr);
return PCIBIOS_SUCCESSFUL;
} else {
mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8));
}
tmp = readl(addr) & mask;
tmp |= val << ((where & 0x3) * 8);
writel(tmp, addr);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_write32);
/**
* pci_bus_set_ops - Set raw operations of pci bus
* @bus: pci bus struct
* @ops: new raw operations
*
* Return previous raw operations
*/
struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops)
{
struct pci_ops *old_ops;
unsigned long flags;
raw_spin_lock_irqsave(&pci_lock, flags);
old_ops = bus->ops;
bus->ops = ops;
raw_spin_unlock_irqrestore(&pci_lock, flags);
return old_ops;
}
EXPORT_SYMBOL(pci_bus_set_ops);
/*
* The following routines are to prevent the user from accessing PCI config
* space when it's unsafe to do so. Some devices require this during BIST and
* we're required to prevent it during D-state transitions.
*
* We have a bit per device to indicate it's blocked and a global wait queue
* for callers to sleep on until devices are unblocked.
*/
static DECLARE_WAIT_QUEUE_HEAD(pci_cfg_wait);
static noinline void pci_wait_cfg(struct pci_dev *dev)
{
DECLARE_WAITQUEUE(wait, current);
__add_wait_queue(&pci_cfg_wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
raw_spin_unlock_irq(&pci_lock);
schedule();
raw_spin_lock_irq(&pci_lock);
} while (dev->block_cfg_access);
__remove_wait_queue(&pci_cfg_wait, &wait);
}
/* Returns 0 on success, negative values indicate error. */
#define PCI_USER_READ_CONFIG(size, type) \
int pci_user_read_config_##size \
(struct pci_dev *dev, int pos, type *val) \
{ \
int ret = PCIBIOS_SUCCESSFUL; \
u32 data = -1; \
if (PCI_##size##_BAD) \
return -EINVAL; \
raw_spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_cfg_access)) \
pci_wait_cfg(dev); \
ret = dev->bus->ops->read(dev->bus, dev->devfn, \
pos, sizeof(type), &data); \
raw_spin_unlock_irq(&pci_lock); \
*val = (type)data; \
return pcibios_err_to_errno(ret); \
} \
EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
/* Returns 0 on success, negative values indicate error. */
#define PCI_USER_WRITE_CONFIG(size, type) \
int pci_user_write_config_##size \
(struct pci_dev *dev, int pos, type val) \
{ \
int ret = PCIBIOS_SUCCESSFUL; \
if (PCI_##size##_BAD) \
return -EINVAL; \
raw_spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_cfg_access)) \
pci_wait_cfg(dev); \
ret = dev->bus->ops->write(dev->bus, dev->devfn, \
pos, sizeof(type), val); \
raw_spin_unlock_irq(&pci_lock); \
return pcibios_err_to_errno(ret); \
} \
EXPORT_SYMBOL_GPL(pci_user_write_config_##size);
PCI_USER_READ_CONFIG(byte, u8)
PCI_USER_READ_CONFIG(word, u16)
PCI_USER_READ_CONFIG(dword, u32)
PCI_USER_WRITE_CONFIG(byte, u8)
PCI_USER_WRITE_CONFIG(word, u16)
PCI_USER_WRITE_CONFIG(dword, u32)
/* VPD access through PCI 2.2+ VPD capability */
/**
* pci_read_vpd - Read one entry from Vital Product Data
* @dev: pci device struct
* @pos: offset in vpd space
* @count: number of bytes to read
* @buf: pointer to where to store result
*/
ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf)
{
if (!dev->vpd || !dev->vpd->ops)
return -ENODEV;
return dev->vpd->ops->read(dev, pos, count, buf);
}
EXPORT_SYMBOL(pci_read_vpd);
/**
* pci_write_vpd - Write entry to Vital Product Data
* @dev: pci device struct
* @pos: offset in vpd space
* @count: number of bytes to write
* @buf: buffer containing write data
*/
ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf)
{
if (!dev->vpd || !dev->vpd->ops)
return -ENODEV;
return dev->vpd->ops->write(dev, pos, count, buf);
}
EXPORT_SYMBOL(pci_write_vpd);
#define PCI_VPD_MAX_SIZE (PCI_VPD_ADDR_MASK + 1)
/**
* pci_vpd_size - determine actual size of Vital Product Data
* @dev: pci device struct
* @old_size: current assumed size, also maximum allowed size
*/
static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size)
{
size_t off = 0;
unsigned char header[1+2]; /* 1 byte tag, 2 bytes length */
while (off < old_size &&
pci_read_vpd(dev, off, 1, header) == 1) {
unsigned char tag;
if (header[0] & PCI_VPD_LRDT) {
/* Large Resource Data Type Tag */
tag = pci_vpd_lrdt_tag(header);
/* Only read length from known tag items */
if ((tag == PCI_VPD_LTIN_ID_STRING) ||
(tag == PCI_VPD_LTIN_RO_DATA) ||
(tag == PCI_VPD_LTIN_RW_DATA)) {
if (pci_read_vpd(dev, off+1, 2,
&header[1]) != 2) {
dev_warn(&dev->dev,
"invalid large VPD tag %02x size at offset %zu",
tag, off + 1);
return 0;
}
off += PCI_VPD_LRDT_TAG_SIZE +
pci_vpd_lrdt_size(header);
}
} else {
/* Short Resource Data Type Tag */
off += PCI_VPD_SRDT_TAG_SIZE +
pci_vpd_srdt_size(header);
tag = pci_vpd_srdt_tag(header);
}
if (tag == PCI_VPD_STIN_END) /* End tag descriptor */
return off;
if ((tag != PCI_VPD_LTIN_ID_STRING) &&
(tag != PCI_VPD_LTIN_RO_DATA) &&
(tag != PCI_VPD_LTIN_RW_DATA)) {
dev_warn(&dev->dev,
"invalid %s VPD tag %02x at offset %zu",
(header[0] & PCI_VPD_LRDT) ? "large" : "short",
tag, off);
return 0;
}
}
return 0;
}
/*
* Wait for last operation to complete.
* This code has to spin since there is no other notification from the PCI
* hardware. Since the VPD is often implemented by serial attachment to an
* EEPROM, it may take many milliseconds to complete.
*
* Returns 0 on success, negative values indicate error.
*/
static int pci_vpd_wait(struct pci_dev *dev)
{
struct pci_vpd *vpd = dev->vpd;
unsigned long timeout = jiffies + msecs_to_jiffies(50);
unsigned long max_sleep = 16;
u16 status;
int ret;
if (!vpd->busy)
return 0;
while (time_before(jiffies, timeout)) {
ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
&status);
if (ret < 0)
return ret;
if ((status & PCI_VPD_ADDR_F) == vpd->flag) {
vpd->busy = 0;
return 0;
}
if (fatal_signal_pending(current))
return -EINTR;
usleep_range(10, max_sleep);
if (max_sleep < 1024)
max_sleep *= 2;
}
dev_warn(&dev->dev, "VPD access failed. This is likely a firmware bug on this device. Contact the card vendor for a firmware update\n");
return -ETIMEDOUT;
}
static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
void *arg)
{
struct pci_vpd *vpd = dev->vpd;
int ret;
loff_t end = pos + count;
u8 *buf = arg;
if (pos < 0)
return -EINVAL;
if (!vpd->valid) {
vpd->valid = 1;
vpd->len = pci_vpd_size(dev, vpd->len);
}
if (vpd->len == 0)
return -EIO;
if (pos > vpd->len)
return 0;
if (end > vpd->len) {
end = vpd->len;
count = end - pos;
}
if (mutex_lock_killable(&vpd->lock))
return -EINTR;
ret = pci_vpd_wait(dev);
if (ret < 0)
goto out;
while (pos < end) {
u32 val;
unsigned int i, skip;
ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
pos & ~3);
if (ret < 0)
break;
vpd->busy = 1;
vpd->flag = PCI_VPD_ADDR_F;
ret = pci_vpd_wait(dev);
if (ret < 0)
break;
ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val);
if (ret < 0)
break;
skip = pos & 3;
for (i = 0; i < sizeof(u32); i++) {
if (i >= skip) {
*buf++ = val;
if (++pos == end)
break;
}
val >>= 8;
}
}
out:
mutex_unlock(&vpd->lock);
return ret ? ret : count;
}
static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
const void *arg)
{
struct pci_vpd *vpd = dev->vpd;
const u8 *buf = arg;
loff_t end = pos + count;
int ret = 0;
if (pos < 0 || (pos & 3) || (count & 3))
return -EINVAL;
if (!vpd->valid) {
vpd->valid = 1;
vpd->len = pci_vpd_size(dev, vpd->len);
}
if (vpd->len == 0)
return -EIO;
if (end > vpd->len)
return -EINVAL;
if (mutex_lock_killable(&vpd->lock))
return -EINTR;
ret = pci_vpd_wait(dev);
if (ret < 0)
goto out;
while (pos < end) {
u32 val;
val = *buf++;
val |= *buf++ << 8;
val |= *buf++ << 16;
val |= *buf++ << 24;
ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val);
if (ret < 0)
break;
ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
pos | PCI_VPD_ADDR_F);
if (ret < 0)
break;
vpd->busy = 1;
vpd->flag = 0;
ret = pci_vpd_wait(dev);
if (ret < 0)
break;
pos += sizeof(u32);
}
out:
mutex_unlock(&vpd->lock);
return ret ? ret : count;
}
static const struct pci_vpd_ops pci_vpd_ops = {
.read = pci_vpd_read,
.write = pci_vpd_write,
};
static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count,
void *arg)
{
struct pci_dev *tdev = pci_get_slot(dev->bus,
PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
ssize_t ret;
if (!tdev)
return -ENODEV;
ret = pci_read_vpd(tdev, pos, count, arg);
pci_dev_put(tdev);
return ret;
}
static ssize_t pci_vpd_f0_write(struct pci_dev *dev, loff_t pos, size_t count,
const void *arg)
{
struct pci_dev *tdev = pci_get_slot(dev->bus,
PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
ssize_t ret;
if (!tdev)
return -ENODEV;
ret = pci_write_vpd(tdev, pos, count, arg);
pci_dev_put(tdev);
return ret;
}
static const struct pci_vpd_ops pci_vpd_f0_ops = {
.read = pci_vpd_f0_read,
.write = pci_vpd_f0_write,
};
int pci_vpd_init(struct pci_dev *dev)
{
struct pci_vpd *vpd;
u8 cap;
cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
if (!cap)
return -ENODEV;
vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC);
if (!vpd)
return -ENOMEM;
vpd->len = PCI_VPD_MAX_SIZE;
if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0)
vpd->ops = &pci_vpd_f0_ops;
else
vpd->ops = &pci_vpd_ops;
mutex_init(&vpd->lock);
vpd->cap = cap;
vpd->busy = 0;
vpd->valid = 0;
dev->vpd = vpd;
return 0;
}
void pci_vpd_release(struct pci_dev *dev)
{
kfree(dev->vpd);
}
/**
* pci_cfg_access_lock - Lock PCI config reads/writes
* @dev: pci device struct
*
* When access is locked, any userspace reads or writes to config
* space and concurrent lock requests will sleep until access is
* allowed via pci_cfg_access_unlocked again.
*/
void pci_cfg_access_lock(struct pci_dev *dev)
{
might_sleep();
raw_spin_lock_irq(&pci_lock);
if (dev->block_cfg_access)
pci_wait_cfg(dev);
dev->block_cfg_access = 1;
raw_spin_unlock_irq(&pci_lock);
}
EXPORT_SYMBOL_GPL(pci_cfg_access_lock);
/**
* pci_cfg_access_trylock - try to lock PCI config reads/writes
* @dev: pci device struct
*
* Same as pci_cfg_access_lock, but will return 0 if access is
* already locked, 1 otherwise. This function can be used from
* atomic contexts.
*/
bool pci_cfg_access_trylock(struct pci_dev *dev)
{
unsigned long flags;
bool locked = true;
raw_spin_lock_irqsave(&pci_lock, flags);
if (dev->block_cfg_access)
locked = false;
else
dev->block_cfg_access = 1;
raw_spin_unlock_irqrestore(&pci_lock, flags);
return locked;
}
EXPORT_SYMBOL_GPL(pci_cfg_access_trylock);
/**
* pci_cfg_access_unlock - Unlock PCI config reads/writes
* @dev: pci device struct
*
* This function allows PCI config accesses to resume.
*/
void pci_cfg_access_unlock(struct pci_dev *dev)
{
unsigned long flags;
raw_spin_lock_irqsave(&pci_lock, flags);
/* This indicates a problem in the caller, but we don't need
* to kill them, unlike a double-block above. */
WARN_ON(!dev->block_cfg_access);
dev->block_cfg_access = 0;
wake_up_all(&pci_cfg_wait);
raw_spin_unlock_irqrestore(&pci_lock, flags);
}
EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);
static inline int pcie_cap_version(const struct pci_dev *dev)
{
return pcie_caps_reg(dev) & PCI_EXP_FLAGS_VERS;
}
static bool pcie_downstream_port(const struct pci_dev *dev)
{
int type = pci_pcie_type(dev);
return type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_DOWNSTREAM;
}
bool pcie_cap_has_lnkctl(const struct pci_dev *dev)
{
int type = pci_pcie_type(dev);
return type == PCI_EXP_TYPE_ENDPOINT ||
type == PCI_EXP_TYPE_LEG_END ||
type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_UPSTREAM ||
type == PCI_EXP_TYPE_DOWNSTREAM ||
type == PCI_EXP_TYPE_PCI_BRIDGE ||
type == PCI_EXP_TYPE_PCIE_BRIDGE;
}
static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
{
return pcie_downstream_port(dev) &&
pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT;
}
static inline bool pcie_cap_has_rtctl(const struct pci_dev *dev)
{
int type = pci_pcie_type(dev);
return type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_RC_EC;
}
static bool pcie_capability_reg_implemented(struct pci_dev *dev, int pos)
{
if (!pci_is_pcie(dev))
return false;
switch (pos) {
case PCI_EXP_FLAGS:
return true;
case PCI_EXP_DEVCAP:
case PCI_EXP_DEVCTL:
case PCI_EXP_DEVSTA:
return true;
case PCI_EXP_LNKCAP:
case PCI_EXP_LNKCTL:
case PCI_EXP_LNKSTA:
return pcie_cap_has_lnkctl(dev);
case PCI_EXP_SLTCAP:
case PCI_EXP_SLTCTL:
case PCI_EXP_SLTSTA:
return pcie_cap_has_sltctl(dev);
case PCI_EXP_RTCTL:
case PCI_EXP_RTCAP:
case PCI_EXP_RTSTA:
return pcie_cap_has_rtctl(dev);
case PCI_EXP_DEVCAP2:
case PCI_EXP_DEVCTL2:
case PCI_EXP_LNKCAP2:
case PCI_EXP_LNKCTL2:
case PCI_EXP_LNKSTA2:
return pcie_cap_version(dev) > 1;
default:
return false;
}
}
/*
* Note that these accessor functions are only for the "PCI Express
* Capability" (see PCIe spec r3.0, sec 7.8). They do not apply to the
* other "PCI Express Extended Capabilities" (AER, VC, ACS, MFVC, etc.)
*/
int pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *val)
{
int ret;
*val = 0;
if (pos & 1)
return -EINVAL;
if (pcie_capability_reg_implemented(dev, pos)) {
ret = pci_read_config_word(dev, pci_pcie_cap(dev) + pos, val);
/*
* Reset *val to 0 if pci_read_config_word() fails, it may
* have been written as 0xFFFF if hardware error happens
* during pci_read_config_word().
*/
if (ret)
*val = 0;
return ret;
}
/*
* For Functions that do not implement the Slot Capabilities,
* Slot Status, and Slot Control registers, these spaces must
* be hardwired to 0b, with the exception of the Presence Detect
* State bit in the Slot Status register of Downstream Ports,
* which must be hardwired to 1b. (PCIe Base Spec 3.0, sec 7.8)
*/
if (pci_is_pcie(dev) && pcie_downstream_port(dev) &&
pos == PCI_EXP_SLTSTA)
*val = PCI_EXP_SLTSTA_PDS;
return 0;
}
EXPORT_SYMBOL(pcie_capability_read_word);
int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val)
{
int ret;
*val = 0;
if (pos & 3)
return -EINVAL;
if (pcie_capability_reg_implemented(dev, pos)) {
ret = pci_read_config_dword(dev, pci_pcie_cap(dev) + pos, val);
/*
* Reset *val to 0 if pci_read_config_dword() fails, it may
* have been written as 0xFFFFFFFF if hardware error happens
* during pci_read_config_dword().
*/
if (ret)
*val = 0;
return ret;
}
if (pci_is_pcie(dev) && pcie_downstream_port(dev) &&
pos == PCI_EXP_SLTSTA)
*val = PCI_EXP_SLTSTA_PDS;
return 0;
}
EXPORT_SYMBOL(pcie_capability_read_dword);
int pcie_capability_write_word(struct pci_dev *dev, int pos, u16 val)
{
if (pos & 1)
return -EINVAL;
if (!pcie_capability_reg_implemented(dev, pos))
return 0;
return pci_write_config_word(dev, pci_pcie_cap(dev) + pos, val);
}
EXPORT_SYMBOL(pcie_capability_write_word);
int pcie_capability_write_dword(struct pci_dev *dev, int pos, u32 val)
{
if (pos & 3)
return -EINVAL;
if (!pcie_capability_reg_implemented(dev, pos))
return 0;
return pci_write_config_dword(dev, pci_pcie_cap(dev) + pos, val);
}
EXPORT_SYMBOL(pcie_capability_write_dword);
int pcie_capability_clear_and_set_word(struct pci_dev *dev, int pos,
u16 clear, u16 set)
{
int ret;
u16 val;
ret = pcie_capability_read_word(dev, pos, &val);
if (!ret) {
val &= ~clear;
val |= set;
ret = pcie_capability_write_word(dev, pos, val);
}
return ret;
}
EXPORT_SYMBOL(pcie_capability_clear_and_set_word);
int pcie_capability_clear_and_set_dword(struct pci_dev *dev, int pos,
u32 clear, u32 set)
{
int ret;
u32 val;
ret = pcie_capability_read_dword(dev, pos, &val);
if (!ret) {
val &= ~clear;
val |= set;
ret = pcie_capability_write_dword(dev, pos, val);
}
return ret;
}
EXPORT_SYMBOL(pcie_capability_clear_and_set_dword);
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