linux/arch/i386/pci/early.c
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   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
  12u32 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
  22u8 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
  31u16 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
  40void 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
  48void 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
  55int early_pci_allowed(void)
  56{
  57        return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
  58                        PCI_PROBE_CONF1;
  59}
  60
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