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
11u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
12{
13 u32 v;
14 outl(value: 0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, port: 0xcf8);
15 v = inl(port: 0xcfc);
16 return v;
17}
18
19u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
20{
21 u8 v;
22 outl(value: 0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, port: 0xcf8);
23 v = inb(port: 0xcfc + (offset&3));
24 return v;
25}
26
27u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
28{
29 u16 v;
30 outl(value: 0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, port: 0xcf8);
31 v = inw(port: 0xcfc + (offset&2));
32 return v;
33}
34
35void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
36 u32 val)
37{
38 outl(value: 0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, port: 0xcf8);
39 outl(value: val, port: 0xcfc);
40}
41
42void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
43{
44 outl(value: 0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, port: 0xcf8);
45 outb(value: val, port: 0xcfc + (offset&3));
46}
47
48void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
49{
50 outl(value: 0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, port: 0xcf8);
51 outw(value: val, port: 0xcfc + (offset&2));
52}
53
54int early_pci_allowed(void)
55{
56 return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
57 PCI_PROBE_CONF1;
58}
59
60