- 根目录:
- drivers
- pci
- access.c
#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);
/**
* 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);
/**
* 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);
/*
* 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 = 0; \
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; \
if (ret > 0) \
ret = -EINVAL; \
return ret; \
}
/* 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 = -EIO; \
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); \
if (ret > 0) \
ret = -EINVAL; \
return ret; \
}
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 */
#define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1)
struct pci_vpd_pci22 {
struct pci_vpd base;
struct mutex lock;
u16 flag;
bool busy;
u8 cap;
};
/*
* 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_pci22_wait(struct pci_dev *dev)
{
struct pci_vpd_pci22 *vpd =
container_of(dev->vpd, struct pci_vpd_pci22, base);
unsigned long timeout = jiffies + HZ/20 + 2;
u16 status;
int ret;
if (!vpd->busy)
return 0;
for (;;) {
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 = false;
return 0;
}
if (time_after(jiffies, timeout)) {
dev_printk(KERN_DEBUG, &dev->dev,
"vpd r/w failed. This is likely a firmware "
"bug on this device. Contact the card "
"vendor for a firmware update.");
return -ETIMEDOUT;
}
if (fatal_signal_pending(current))
return -EINTR;
if (!cond_resched())
udelay(10);
}
}
static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
void *arg)
{
struct pci_vpd_pci22 *vpd =
container_of(dev->vpd, struct pci_vpd_pci22, base);
int ret;
loff_t end = pos + count;
u8 *buf = arg;
if (pos < 0 || pos > vpd->base.len || end > vpd->base.len)
return -EINVAL;
if (mutex_lock_killable(&vpd->lock))
return -EINTR;
ret = pci_vpd_pci22_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 = true;
vpd->flag = PCI_VPD_ADDR_F;
ret = pci_vpd_pci22_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_pci22_write(struct pci_dev *dev, loff_t pos, size_t count,
const void *arg)
{
struct pci_vpd_pci22 *vpd =
container_of(dev->vpd, struct pci_vpd_pci22, base);
const u8 *buf = arg;
loff_t end = pos + count;
int ret = 0;
if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len)
return -EINVAL;
if (mutex_lock_killable(&vpd->lock))
return -EINTR;
ret = pci_vpd_pci22_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 = true;
vpd->flag = 0;
ret = pci_vpd_pci22_wait(dev);
if (ret < 0)
break;
pos += sizeof(u32);
}
out:
mutex_unlock(&vpd->lock);
return ret ? ret : count;
}
static void pci_vpd_pci22_release(struct pci_dev *dev)
{
kfree(container_of(dev->vpd, struct pci_vpd_pci22, base));
}
static const struct pci_vpd_ops pci_vpd_pci22_ops = {
.read = pci_vpd_pci22_read,
.write = pci_vpd_pci22_write,
.release = pci_vpd_pci22_release,
};
int pci_vpd_pci22_init(struct pci_dev *dev)
{
struct pci_vpd_pci22 *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->base.len = PCI_VPD_PCI22_SIZE;
vpd->base.ops = &pci_vpd_pci22_ops;
mutex_init(&vpd->lock);
vpd->cap = cap;
vpd->busy = false;
dev->vpd = &vpd->base;
return 0;
}
/**
* pci_vpd_truncate - Set available Vital Product Data size
* @dev: pci device struct
* @size: available memory in bytes
*
* Adjust size of available VPD area.
*/
int pci_vpd_truncate(struct pci_dev *dev, size_t size)
{
if (!dev->vpd)
return -EINVAL;
/* limited by the access method */
if (size > dev->vpd->len)
return -EINVAL;
dev->vpd->len = size;
if (dev->vpd->attr)
dev->vpd->attr->size = size;
return 0;
}
EXPORT_SYMBOL(pci_vpd_truncate);
/**
* 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);