UEFI应用与编程--读写Pci配置空间

最新推荐文章于 2022-11-08 14:11:24 发布

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最新推荐文章于 2022-11-08 14:11:24 发布 · 6.4k 阅读

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CC 4.0 BY-SA版权

文章标签：

#uefi #edk2 #udk #bios #pci

本文档展示了如何在UEFI环境下使用EFI_BOOT_SERVICES和EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL来读写PCI配置空间。通过LocateHandleBuffer获取PCI根桥IO协议句柄，然后调用Pci.Read和Pci.Write方法进行读写操作。

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#include <Protocol/PciRootBridgeIo.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
#include "UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.h"
#include <Uefi.h>
extern EFI_BOOT_SERVICES  *gBS;


VOID
MmPciWrite (
  IN UINT64 Address, //Address = bbddffrr
  IN UINT64 Value
)
{
  EFI_STATUS                      Status;
  EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL *IoDev;
  EFI_HANDLE                      *HandleBuffer;
  UINTN                           BufferSize;
  UINTN                           Index;
  EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_WIDTH                    Width;
  
  IoDev         = NULL;
  HandleBuffer  = NULL;
  BufferSize    = 0;
  Width         = EfiPciWidthUint8;
  

  Status = gBS->LocateHandleBuffer (
           ByProtocol,
           &gEfiPciRootBridgeIoProtocolGuid,
           NULL,
           &BufferSize,
           &HandleBuffer
          );
  if (EFI_ERROR (Status)) {
    P