readx.c

来自「linux内核」· C语言 代码 · 共 53 行

#include "pci/pci.h"
#include <string.h>

TYPE BWL(pci_read) (pciaddr_t a)
{
  TYPE r;

  for (;;) {
    switch ( __pci_cfg_type ) {
    case PCI_CFG_AUTO:
      pci_set_config_type(PCI_CFG_AUTO);
      break;			/* Try again */
      
    case PCI_CFG_TYPE1:
      {
	uint32_t oldcf8;
	cli();
	oldcf8 = inl(0xcf8);
	outl(a, 0xcf8);
	r = BWL(in) (0xcfc + (a & 3));
	outl(oldcf8, 0xcf8);
	sti();
      }
      return r;
      
    case PCI_CFG_TYPE2:
      {
	uint8_t oldcf8, oldcfa;
	
	if ( a & (0x10 << 11) )
	  return (TYPE)~0;	/* Device 16-31 not supported */
	
	cli();
	oldcf8 = inb(0xcf8);
	oldcfa = inb(0xcfa);
	outb(0xf0 + ((a >> (8-1)) & 0x0e), 0xcf8);
	outb(a >> 16, 0xcfa);
	r = BWL(in) (0xc000 + ((a >> (11-8)) & 0xf00) + (a & 0xff));
	outb(oldcf8, 0xcf8);
	outb(oldcfa, 0xcfa);
	sti();
      }
      return r;

    case PCI_CFG_BIOS:
      return (TYPE) __pci_read_bios(BIOSCALL, a);
      
    default:
      return (TYPE)~0;
    }
  }
}