linux/drivers/pci/access.c
Ben Hutchings 94e6108803 PCI: Expose PCI VPD through sysfs
Vital Product Data (VPD) may be exposed by PCI devices in several
ways.  It is generally unsafe to read this information through the
existing interfaces to user-land because of stateful interfaces.

This adds:
- abstract operations for VPD access (struct pci_vpd_ops)
- VPD state information in struct pci_dev (struct pci_vpd)
- an implementation of the VPD access method specified in PCI 2.2
  (in access.c)
- a 'vpd' binary file in sysfs directories for PCI devices with VPD
  operations defined

It adds a probe for PCI 2.2 VPD in pci_scan_device() and release of
VPD state in pci_release_dev().

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-20 21:47:07 -07:00

339 lines
8.4 KiB
C

#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/wait.h>
#include "pci.h"
/*
* This interrupt-safe spinlock protects all accesses to PCI
* configuration space.
*/
static DEFINE_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; \
spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->read(bus, devfn, pos, len, &data); \
*value = (type)data; \
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; \
spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->write(bus, devfn, pos, len, value); \
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);
/*
* 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_ucfg_wait);
static noinline void pci_wait_ucfg(struct pci_dev *dev)
{
DECLARE_WAITQUEUE(wait, current);
__add_wait_queue(&pci_ucfg_wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&pci_lock);
schedule();
spin_lock_irq(&pci_lock);
} while (dev->block_ucfg_access);
__remove_wait_queue(&pci_ucfg_wait, &wait);
}
#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 PCIBIOS_BAD_REGISTER_NUMBER; \
spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \
ret = dev->bus->ops->read(dev->bus, dev->devfn, \
pos, sizeof(type), &data); \
spin_unlock_irq(&pci_lock); \
*val = (type)data; \
return ret; \
}
#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 PCIBIOS_BAD_REGISTER_NUMBER; \
spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \
ret = dev->bus->ops->write(dev->bus, dev->devfn, \
pos, sizeof(type), val); \
spin_unlock_irq(&pci_lock); \
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;
spinlock_t lock; /* controls access to hardware and the flags */
u8 cap;
bool busy;
bool flag; /* value of F bit to wait for */
};
/* Wait for last operation to complete */
static int pci_vpd_pci22_wait(struct pci_dev *dev)
{
struct pci_vpd_pci22 *vpd =
container_of(dev->vpd, struct pci_vpd_pci22, base);
u16 flag, status;
int wait;
int ret;
if (!vpd->busy)
return 0;
flag = vpd->flag ? PCI_VPD_ADDR_F : 0;
wait = vpd->flag ? 10 : 1000; /* read: 100 us; write: 10 ms */
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) == flag) {
vpd->busy = false;
return 0;
}
if (wait-- == 0)
return -ETIMEDOUT;
udelay(10);
}
}
static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size,
char *buf)
{
struct pci_vpd_pci22 *vpd =
container_of(dev->vpd, struct pci_vpd_pci22, base);
u32 val;
int ret;
int begin, end, i;
if (pos < 0 || pos > PCI_VPD_PCI22_SIZE ||
size > PCI_VPD_PCI22_SIZE - pos)
return -EINVAL;
if (size == 0)
return 0;
spin_lock_irq(&vpd->lock);
ret = pci_vpd_pci22_wait(dev);
if (ret < 0)
goto out;
ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
pos & ~3);
if (ret < 0)
goto out;
vpd->busy = true;
vpd->flag = 1;
ret = pci_vpd_pci22_wait(dev);
if (ret < 0)
goto out;
ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA,
&val);
out:
spin_unlock_irq(&vpd->lock);
if (ret < 0)
return ret;
/* Convert to bytes */
begin = pos & 3;
end = min(4, begin + size);
for (i = 0; i < end; ++i) {
if (i >= begin)
*buf++ = val;
val >>= 8;
}
return end - begin;
}
static int pci_vpd_pci22_write(struct pci_dev *dev, int pos, int size,
const char *buf)
{
struct pci_vpd_pci22 *vpd =
container_of(dev->vpd, struct pci_vpd_pci22, base);
u32 val;
int ret;
if (pos < 0 || pos > PCI_VPD_PCI22_SIZE || pos & 3 ||
size > PCI_VPD_PCI22_SIZE - pos || size < 4)
return -EINVAL;
val = (u8) *buf++;
val |= ((u8) *buf++) << 8;
val |= ((u8) *buf++) << 16;
val |= ((u32)(u8) *buf++) << 24;
spin_lock_irq(&vpd->lock);
ret = pci_vpd_pci22_wait(dev);
if (ret < 0)
goto out;
ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA,
val);
if (ret < 0)
goto out;
ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
pos | PCI_VPD_ADDR_F);
if (ret < 0)
goto out;
vpd->busy = true;
vpd->flag = 0;
ret = pci_vpd_pci22_wait(dev);
out:
spin_unlock_irq(&vpd->lock);
if (ret < 0)
return ret;
return 4;
}
static int pci_vpd_pci22_get_size(struct pci_dev *dev)
{
return PCI_VPD_PCI22_SIZE;
}
static void pci_vpd_pci22_release(struct pci_dev *dev)
{
kfree(container_of(dev->vpd, struct pci_vpd_pci22, base));
}
static struct pci_vpd_ops pci_vpd_pci22_ops = {
.read = pci_vpd_pci22_read,
.write = pci_vpd_pci22_write,
.get_size = pci_vpd_pci22_get_size,
.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.ops = &pci_vpd_pci22_ops;
spin_lock_init(&vpd->lock);
vpd->cap = cap;
vpd->busy = false;
dev->vpd = &vpd->base;
return 0;
}
/**
* pci_block_user_cfg_access - Block userspace PCI config reads/writes
* @dev: pci device struct
*
* When user access is blocked, any reads or writes to config space will
* sleep until access is unblocked again. We don't allow nesting of
* block/unblock calls.
*/
void pci_block_user_cfg_access(struct pci_dev *dev)
{
unsigned long flags;
int was_blocked;
spin_lock_irqsave(&pci_lock, flags);
was_blocked = dev->block_ucfg_access;
dev->block_ucfg_access = 1;
spin_unlock_irqrestore(&pci_lock, flags);
/* If we BUG() inside the pci_lock, we're guaranteed to hose
* the machine */
BUG_ON(was_blocked);
}
EXPORT_SYMBOL_GPL(pci_block_user_cfg_access);
/**
* pci_unblock_user_cfg_access - Unblock userspace PCI config reads/writes
* @dev: pci device struct
*
* This function allows userspace PCI config accesses to resume.
*/
void pci_unblock_user_cfg_access(struct pci_dev *dev)
{
unsigned long flags;
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_ucfg_access);
dev->block_ucfg_access = 0;
wake_up_all(&pci_ucfg_wait);
spin_unlock_irqrestore(&pci_lock, flags);
}
EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access);