xref: /openbmc/linux/arch/x86/pci/early.c (revision 643d1f7f)
1 #include <linux/kernel.h>
2 #include <linux/pci.h>
3 #include <asm/pci-direct.h>
4 #include <asm/io.h>
5 #include "pci.h"
6 
7 /* Direct PCI access. This is used for PCI accesses in early boot before
8    the PCI subsystem works. */
9 
10 #define PDprintk(x...)
11 
12 u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
13 {
14 	u32 v;
15 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
16 	v = inl(0xcfc);
17 	if (v != 0xffffffff)
18 		PDprintk("%x reading 4 from %x: %x\n", slot, offset, v);
19 	return v;
20 }
21 
22 u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
23 {
24 	u8 v;
25 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
26 	v = inb(0xcfc + (offset&3));
27 	PDprintk("%x reading 1 from %x: %x\n", slot, offset, v);
28 	return v;
29 }
30 
31 u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
32 {
33 	u16 v;
34 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
35 	v = inw(0xcfc + (offset&2));
36 	PDprintk("%x reading 2 from %x: %x\n", slot, offset, v);
37 	return v;
38 }
39 
40 void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
41 				    u32 val)
42 {
43 	PDprintk("%x writing to %x: %x\n", slot, offset, val);
44 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
45 	outl(val, 0xcfc);
46 }
47 
48 void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
49 {
50 	PDprintk("%x writing to %x: %x\n", slot, offset, val);
51 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
52 	outb(val, 0xcfc);
53 }
54 
55 int early_pci_allowed(void)
56 {
57 	return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
58 			PCI_PROBE_CONF1;
59 }
60