xref: /linux/drivers/pci/access.c (revision 4bedea94545165364618d403d03b61d797acba0b)
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 DEFINE_SPINLOCK(pci_lock);
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);
63