#include <linux/pci.h>
#include <linux/module.h>
#include <linux/ioport.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);
static u32 pci_user_cached_config(struct pci_dev *dev, int pos)
{
u32 data;
data = dev->saved_config_space[pos/sizeof(dev->saved_config_space[0])];
data >>= (pos % sizeof(dev->saved_config_space[0])) * 8;
return data;
}
#define PCI_USER_READ_CONFIG(size,type) \
int pci_user_read_config_##size \
(struct pci_dev *dev, int pos, type *val) \
{ \
unsigned long flags; \
int ret = 0; \
u32 data = -1; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
spin_lock_irqsave(&pci_lock, flags); \
if (likely(!dev->block_ucfg_access)) \
ret = dev->bus->ops->read(dev->bus, dev->devfn, \
pos, sizeof(type), &data); \
else if (pos < sizeof(dev->saved_config_space)) \
data = pci_user_cached_config(dev, pos); \
spin_unlock_irqrestore(&pci_lock, flags); \
*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) \
{ \
unsigned long flags; \
int ret = -EIO; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
spin_lock_irqsave(&pci_lock, flags); \
if (likely(!dev->block_ucfg_access)) \
ret = dev->bus->ops->write(dev->bus, dev->devfn, \
pos, sizeof(type), val); \
spin_unlock_irqrestore(&pci_lock, flags); \
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
*
* This function blocks any userspace PCI config accesses from occurring.
* When blocked, any writes will be bit bucketed and reads will return the
* data saved using pci_save_state for the first 64 bytes of config
* space and return 0xff for all other config reads.
**/
void pci_block_user_cfg_access(struct pci_dev *dev)
{
unsigned long flags;
pci_save_state(dev);
/* spinlock to synchronize with anyone reading config space now */
spin_lock_irqsave(&pci_lock, flags);
dev->block_ucfg_access = 1;
spin_unlock_irqrestore(&pci_lock, flags);
}
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;
/* spinlock to synchronize with anyone reading saved config space */
spin_lock_irqsave(&pci_lock, flags);
dev->block_ucfg_access = 0;
spin_unlock_irqrestore(&pci_lock, flags);
}
EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access);
