LXR linux/arch/x86/pci/early.c

   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(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  15        v = inl(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(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  23        v = inb(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(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  31        v = inw(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(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  39        outl(val, 0xcfc);
  40}
  41
  42void 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
  48void 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
  54int early_pci_allowed(void)
  55{
  56        return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
  57                        PCI_PROBE_CONF1;
  58}
  59
  60