#include <linux/pci.h>
#include <linux/module.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)
/**
* 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);
