drivers/pci/access.c

   1 #include <linux/pci.h>
   2 #include <linux/module.h>
   3 #include <linux/ioport.h>
   4
   5 /*
   6  * This interrupt-safe spinlock protects all accesses to PCI
   7  * configuration space.
   8  */
   9
  10 static spinlock_t pci_lock = SPIN_LOCK_UNLOCKED;
  11
  12 /*
  13  *  Wrappers for all PCI configuration access functions.  They just check
  14  *  alignment, do locking and call the low-level functions pointed to
  15  *  by pci_dev->ops.
  16  */
  17
  18 #define PCI_byte_BAD 0
  19 #define PCI_word_BAD (pos & 1)
  20 #define PCI_dword_BAD (pos & 3)
  21
  22 #define PCI_OP_READ(size,type,len) \
  23 int pci_bus_read_config_##size \
  24         (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \
  25 {                                                                       \
  26         int res;                                                        \
  27         unsigned long flags;                                            \
  28         u32 data = 0;                                                   \
  29         if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER;       \
  30         spin_lock_irqsave(&pci_lock, flags);                            \
  31         res = bus->ops->read(bus, devfn, pos, len, &data);              \
  32         *value = (type)data;                                            \
  33         spin_unlock_irqrestore(&pci_lock, flags);                       \
  34         return res;                                                     \
  35 }
  36
  37 #define PCI_OP_WRITE(size,type,len) \
  38 int pci_bus_write_config_##size \
  39         (struct pci_bus *bus, unsigned int devfn, int pos, type value)  \
  40 {                                                                       \
  41         int res;                                                        \
  42         unsigned long flags;                                            \
  43         if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER;       \
  44         spin_lock_irqsave(&pci_lock, flags);                            \
  45         res = bus->ops->write(bus, devfn, pos, len, value);             \
  46         spin_unlock_irqrestore(&pci_lock, flags);                       \
  47         return res;                                                     \
  48 }
  49
  50 PCI_OP_READ(byte, u8, 1)
  51 PCI_OP_READ(word, u16, 2)
  52 PCI_OP_READ(dword, u32, 4)
  53 PCI_OP_WRITE(byte, u8, 1)
  54 PCI_OP_WRITE(word, u16, 2)
  55 PCI_OP_WRITE(dword, u32, 4)
  56
  57 EXPORT_SYMBOL(pci_bus_read_config_byte);
  58 EXPORT_SYMBOL(pci_bus_read_config_word);
  59 EXPORT_SYMBOL(pci_bus_read_config_dword);
  60 EXPORT_SYMBOL(pci_bus_write_config_byte);
  61 EXPORT_SYMBOL(pci_bus_write_config_word);
  62 EXPORT_SYMBOL(pci_bus_write_config_dword);