1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/pci.h>
4 #include <asm/pci-direct.h>
5 #include <asm/io.h>
6 #include <asm/pci_x86.h>
7
8 /* Direct PCI access. This is used for PCI accesses in early boot before
9 the PCI subsystem works. */
10
11 u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
12 {
13 u32 v;
14 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
15 v = inl(0xcfc);
16 return v;
17 }
18
19 u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
20 {
21 u8 v;
22 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
23 v = inb(0xcfc + (offset&3));
24 return v;
25 }
26
27 u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
28 {
29 u16 v;
30 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
31 v = inw(0xcfc + (offset&2));
32 return v;
33 }
34
35 void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
36 u32 val)
37 {
38 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
39 outl(val, 0xcfc);
40 }
41
42 void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
43 {
44 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
45 outb(val, 0xcfc + (offset&3));
46 }
47
48 void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
49 {
50 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
51 outw(val, 0xcfc + (offset&2));
52 }
53
54 int early_pci_allowed(void)
55 {
56 return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
57 PCI_PROBE_CONF1;
58 }
59
60
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