/** @file
  PCI Rom supporting funtions implementation for PCI Bus module.

Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "PciBus.h"

/**
  Load the EFI Image from Option ROM

  @param PciIoDevice   PCI IO device instance.
  @param FilePath      The file path of the EFI Image
  @param BufferSize    On input the size of Buffer in bytes. On output with a return
                       code of EFI_SUCCESS, the amount of data transferred to Buffer.
                       On output with a return code of EFI_BUFFER_TOO_SMALL,
                       the size of Buffer required to retrieve the requested file.
  @param Buffer        The memory buffer to transfer the file to. If Buffer is NULL,
                       then no the size of the requested file is returned in BufferSize.

  @retval EFI_SUCCESS           The file was loaded.
  @retval EFI_INVALID_PARAMETER FilePath is not a valid device path, or
                                BufferSize is NULL.
  @retval EFI_NOT_FOUND         Not found PCI Option Rom on PCI device.
  @retval EFI_DEVICE_ERROR      Failed to decompress PCI Option Rom image.
  @retval EFI_BUFFER_TOO_SMALL  The BufferSize is too small to read the current directory entry.
                                BufferSize has been updated with the size needed to complete the request.
**/
EFI_STATUS
LocalLoadFile2 (
  IN PCI_IO_DEVICE            *PciIoDevice,
  IN EFI_DEVICE_PATH_PROTOCOL *FilePath,
  IN OUT UINTN                *BufferSize,
  IN VOID                     *Buffer      OPTIONAL
  )
{
  EFI_STATUS                                Status;
  MEDIA_RELATIVE_OFFSET_RANGE_DEVICE_PATH   *EfiOpRomImageNode;
  EFI_PCI_EXPANSION_ROM_HEADER              *EfiRomHeader;
  PCI_DATA_STRUCTURE                        *Pcir;
  UINT32                                    ImageSize;
  UINT8                                     *ImageBuffer;
  UINT32                                    ImageLength;
  UINT32                                    DestinationSize;
  UINT32                                    ScratchSize;
  VOID                                      *Scratch;
  EFI_DECOMPRESS_PROTOCOL                   *Decompress;
  UINT32                                    InitializationSize;

  EfiOpRomImageNode = (MEDIA_RELATIVE_OFFSET_RANGE_DEVICE_PATH *) FilePath;
  if ((EfiOpRomImageNode == NULL) ||
      (DevicePathType (FilePath) != MEDIA_DEVICE_PATH) ||
      (DevicePathSubType (FilePath) != MEDIA_RELATIVE_OFFSET_RANGE_DP) ||
      (DevicePathNodeLength (FilePath) != sizeof (MEDIA_RELATIVE_OFFSET_RANGE_DEVICE_PATH)) ||
      (!IsDevicePathEnd (NextDevicePathNode (FilePath))) ||
      (EfiOpRomImageNode->StartingOffset > EfiOpRomImageNode->EndingOffset) ||
      (EfiOpRomImageNode->EndingOffset >= PciIoDevice->RomSize) ||
      (BufferSize == NULL)
      ) {
    return EFI_INVALID_PARAMETER;
  }

  EfiRomHeader = (EFI_PCI_EXPANSION_ROM_HEADER *) (
      (UINT8 *) PciIoDevice->PciIo.RomImage + EfiOpRomImageNode->StartingOffset
      );
  if (EfiRomHeader->Signature != PCI_EXPANSION_ROM_HEADER_SIGNATURE) {
    return EFI_NOT_FOUND;
  }


  Pcir = (PCI_DATA_STRUCTURE *) ((UINT8 *) EfiRomHeader + EfiRomHeader->PcirOffset);
  ASSERT (Pcir->Signature == PCI_DATA_STRUCTURE_SIGNATURE);

  if ((Pcir->CodeType == PCI_CODE_TYPE_EFI_IMAGE) &&
      (EfiRomHeader->EfiSignature == EFI_PCI_EXPANSION_ROM_HEADER_EFISIGNATURE) &&
      ((EfiRomHeader->EfiSubsystem == EFI_IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER) ||
       (EfiRomHeader->EfiSubsystem == EFI_IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER)) &&
      (EfiRomHeader->CompressionType <= EFI_PCI_EXPANSION_ROM_HEADER_COMPRESSED)
       ) {

    ImageSize = Pcir->ImageLength * 512;
    InitializationSize = (UINT32) EfiRomHeader->InitializationSize * 512;
    if (InitializationSize > ImageSize || EfiRomHeader->EfiImageHeaderOffset >=  InitializationSize) {
      return EFI_NOT_FOUND;
    }

    ImageBuffer             = (UINT8 *) EfiRomHeader + EfiRomHeader->EfiImageHeaderOffset;
    ImageLength             = InitializationSize - EfiRomHeader->EfiImageHeaderOffset;

    if (EfiRomHeader->CompressionType != EFI_PCI_EXPANSION_ROM_HEADER_COMPRESSED) {
      //
      // Uncompressed: Copy the EFI Image directly to user's buffer
      //
      if (Buffer == NULL || *BufferSize < ImageLength) {
        *BufferSize = ImageLength;
        return EFI_BUFFER_TOO_SMALL;
      }

      *BufferSize = ImageLength;
      CopyMem (Buffer, ImageBuffer, ImageLength);
      return EFI_SUCCESS;

    } else {
      //
      // Compressed: Uncompress before copying
      //
      Status = gBS->LocateProtocol (&gEfiDecompressProtocolGuid, NULL, (VOID **) &Decompress);
      if (EFI_ERROR(Status)) {
        return EFI_DEVICE_ERROR;
      }
      Status = Decompress->GetInfo (
                             Decompress,
                             ImageBuffer,
                             ImageLength,
                             &DestinationSize,
                             &ScratchSize
                             );
      if (EFI_ERROR(Status)) {
        return EFI_DEVICE_ERROR;
      }

      if (Buffer == NULL || *BufferSize < DestinationSize) {
        *BufferSize = DestinationSize;
        return EFI_BUFFER_TOO_SMALL;
      }

      *BufferSize = DestinationSize;
      Scratch = AllocatePool (ScratchSize);
      if (Scratch == NULL) {
        return EFI_DEVICE_ERROR;
      }

      Status = Decompress->Decompress (
                             Decompress,
                             ImageBuffer,
                             ImageLength,
                             Buffer,
                             DestinationSize,
                             Scratch,
                             ScratchSize
                             );
      FreePool(Scratch);

      if (EFI_ERROR(Status)) {
        return EFI_DEVICE_ERROR;
      }
      return EFI_SUCCESS;
    }
  }

  return EFI_NOT_FOUND;
}

/**
  Initialize a PCI LoadFile2 instance.

  @param PciIoDevice   PCI IO Device.

**/
VOID
InitializePciLoadFile2 (
  IN PCI_IO_DEVICE       *PciIoDevice
  )
{
  PciIoDevice->LoadFile2.LoadFile = LoadFile2;
}

/**
  Causes the driver to load a specified file.

  @param This        Indicates a pointer to the calling context.
  @param FilePath    The device specific path of the file to load.
  @param BootPolicy  Should always be FALSE.
  @param BufferSize  On input the size of Buffer in bytes. On output with a return
                     code of EFI_SUCCESS, the amount of data transferred to Buffer.
                     On output with a return code of EFI_BUFFER_TOO_SMALL,
                     the size of Buffer required to retrieve the requested file.
  @param Buffer      The memory buffer to transfer the file to. If Buffer is NULL,
                     then no the size of the requested file is returned in BufferSize.

  @retval EFI_SUCCESS           The file was loaded.
  @retval EFI_UNSUPPORTED       BootPolicy is TRUE.
  @retval EFI_INVALID_PARAMETER FilePath is not a valid device path, or
                                BufferSize is NULL.
  @retval EFI_NOT_FOUND         Not found PCI Option Rom on PCI device.
  @retval EFI_DEVICE_ERROR      Failed to decompress PCI Option Rom image.
  @retval EFI_BUFFER_TOO_SMALL  The BufferSize is too small to read the current directory entry.
                                BufferSize has been updated with the size needed to complete the request.

**/
EFI_STATUS
EFIAPI
LoadFile2 (
  IN EFI_LOAD_FILE2_PROTOCOL  *This,
  IN EFI_DEVICE_PATH_PROTOCOL *FilePath,
  IN BOOLEAN                  BootPolicy,
  IN OUT UINTN                *BufferSize,
  IN VOID                     *Buffer      OPTIONAL
  )
{
  PCI_IO_DEVICE                             *PciIoDevice;

  if (BootPolicy) {
    return EFI_UNSUPPORTED;
  }
  PciIoDevice = PCI_IO_DEVICE_FROM_LOAD_FILE2_THIS (This);

  return LocalLoadFile2 (
           PciIoDevice,
           FilePath,
           BufferSize,
           Buffer
           );
}

/**
  Get Pci device's oprom information.

  @param PciIoDevice    Input Pci device instance.
                        Output Pci device instance with updated OptionRom size.

  @retval EFI_NOT_FOUND Pci device has not Option Rom.
  @retval EFI_SUCCESS   Pci device has Option Rom.

**/
EFI_STATUS
GetOpRomInfo (
  IN OUT PCI_IO_DEVICE    *PciIoDevice
  )
{
  UINT8                           RomBarIndex;
  UINT32                          AllOnes;
  UINT64                          Address;
  EFI_STATUS                      Status;
  UINT8                           Bus;
  UINT8                           Device;
  UINT8                           Function;
  EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL *PciRootBridgeIo;

  Bus             = PciIoDevice->BusNumber;
  Device          = PciIoDevice->DeviceNumber;
  Function        = PciIoDevice->FunctionNumber;

  PciRootBridgeIo = PciIoDevice->PciRootBridgeIo;

  //
  // Offset is 0x30 if is not ppb
  //

  //
  // 0x30
  //
  RomBarIndex = PCI_EXPANSION_ROM_BASE;

  if (IS_PCI_BRIDGE (&PciIoDevice->Pci)) {
    //
    // If is ppb, 0x38
    //
    RomBarIndex = PCI_BRIDGE_ROMBAR;
  }
  //
  // The bit0 is 0 to prevent the enabling of the Rom address decoder
  //
  AllOnes = 0xfffffffe;
  Address = EFI_PCI_ADDRESS (Bus, Device, Function, RomBarIndex);

  Status = PciRootBridgeIo->Pci.Write (
                                  PciRootBridgeIo,
                                  EfiPciWidthUint32,
                                  Address,
                                  1,
                                  &AllOnes
                                  );
  if (EFI_ERROR(Status)) {
    return EFI_NOT_FOUND;
  }

  //
  // Read back
  //
  Status = PciRootBridgeIo->Pci.Read(
                                  PciRootBridgeIo,
                                  EfiPciWidthUint32,
                                  Address,
                                  1,
                                  &AllOnes
                                  );
  if (EFI_ERROR(Status)) {
    return EFI_NOT_FOUND;
  }

  //
  // Bits [1, 10] are reserved
  //
  AllOnes &= 0xFFFFF800;
  if ((AllOnes == 0) || (AllOnes == 0xFFFFF800)) {
    return EFI_NOT_FOUND;
  }

  PciIoDevice->RomSize = (~AllOnes) + 1;
  return EFI_SUCCESS;
}

/**
  Check if the RomImage contains EFI Images.

  @param  RomImage  The ROM address of Image for check.
  @param  RomSize   Size of ROM for check.

  @retval TRUE     ROM contain EFI Image.
  @retval FALSE    ROM not contain EFI Image.

**/
BOOLEAN
ContainEfiImage (
  IN VOID            *RomImage,
  IN UINT64          RomSize
  )
{
  PCI_EXPANSION_ROM_HEADER  *RomHeader;
  PCI_DATA_STRUCTURE        *RomPcir;
  UINT8                     Indicator;

  Indicator = 0;
  RomHeader = RomImage;
  if (RomHeader == NULL) {
    return FALSE;
  }

  do {
    if (RomHeader->Signature != PCI_EXPANSION_ROM_HEADER_SIGNATURE) {
      RomHeader = (PCI_EXPANSION_ROM_HEADER *) ((UINT8 *) RomHeader + 512);
      continue;
    }

    //
    // The PCI Data Structure must be DWORD aligned.
    //
    if (RomHeader->PcirOffset == 0 ||
        (RomHeader->PcirOffset & 3) != 0 ||
        (UINT8 *) RomHeader + RomHeader->PcirOffset + sizeof (PCI_DATA_STRUCTURE) > (UINT8 *) RomImage + RomSize) {
      break;
    }

    RomPcir = (PCI_DATA_STRUCTURE *) ((UINT8 *) RomHeader + RomHeader->PcirOffset);
    if (RomPcir->Signature != PCI_DATA_STRUCTURE_SIGNATURE) {
      break;
    }

    if (RomPcir->CodeType == PCI_CODE_TYPE_EFI_IMAGE) {
      return TRUE;
    }

    Indicator = RomPcir->Indicator;
    RomHeader = (PCI_EXPANSION_ROM_HEADER *) ((UINT8 *) RomHeader + RomPcir->ImageLength * 512);
  } while (((UINT8 *) RomHeader < (UINT8 *) RomImage + RomSize) && ((Indicator & 0x80) == 0x00));

  return FALSE;
}

/**
  Load Option Rom image for specified PCI device.

  @param PciDevice Pci device instance.
  @param RomBase   Base address of Option Rom.

  @retval EFI_OUT_OF_RESOURCES No enough memory to hold image.
  @retval EFI_SUCESS           Successfully loaded Option Rom.

**/
EFI_STATUS
LoadOpRomImage (
  IN PCI_IO_DEVICE   *PciDevice,
  IN UINT64          RomBase
  )
{
  UINT8                     RomBarIndex;
  UINT8                     Indicator;
  UINT16                    OffsetPcir;
  UINT32                    RomBarOffset;
  UINT32                    RomBar;
  EFI_STATUS                RetStatus;
  BOOLEAN                   FirstCheck;
  UINT8                     *Image;
  PCI_EXPANSION_ROM_HEADER  *RomHeader;
  PCI_DATA_STRUCTURE        *RomPcir;
  UINT64                    RomSize;
  UINT64                    RomImageSize;
  UINT32                    LegacyImageLength;
  UINT8                     *RomInMemory;
  UINT8                     CodeType;

  RomSize       = PciDevice->RomSize;

  Indicator     = 0;
  RomImageSize  = 0;
  RomInMemory   = NULL;
  CodeType      = 0xFF;

  //
  // Get the RomBarIndex
  //

  //
  // 0x30
  //
  RomBarIndex = PCI_EXPANSION_ROM_BASE;
  if (IS_PCI_BRIDGE (&(PciDevice->Pci))) {
    //
    // if is ppb
    //

    //
    // 0x38
    //
    RomBarIndex = PCI_BRIDGE_ROMBAR;
  }
  //
  // Allocate memory for Rom header and PCIR
  //
  RomHeader = AllocatePool (sizeof (PCI_EXPANSION_ROM_HEADER));
  if (RomHeader == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  RomPcir = AllocatePool (sizeof (PCI_DATA_STRUCTURE));
  if (RomPcir == NULL) {
    FreePool(RomHeader);
    return EFI_OUT_OF_RESOURCES;
  }

  RomBar = (UINT32) RomBase;

  //
  // Enable RomBar
  //
  RomDecode (PciDevice, RomBarIndex, RomBar, TRUE);

  RomBarOffset  = RomBar;
  RetStatus     = EFI_NOT_FOUND;
  FirstCheck    = TRUE;
  LegacyImageLength = 0;

  do {
    PciDevice->PciRootBridgeIo->Mem.Read (
                                      PciDevice->PciRootBridgeIo,
                                      EfiPciWidthUint8,
                                      RomBarOffset,
                                      sizeof (PCI_EXPANSION_ROM_HEADER),
                                      (UINT8 *) RomHeader
                                      );

    if (RomHeader->Signature != PCI_EXPANSION_ROM_HEADER_SIGNATURE) {
      RomBarOffset = RomBarOffset + 512;
      if (FirstCheck) {
        break;
      } else {
        RomImageSize = RomImageSize + 512;
        continue;
      }
    }

    FirstCheck  = FALSE;
    OffsetPcir  = RomHeader->PcirOffset;
    //
    // If the pointer to the PCI Data Structure is invalid, no further images can be located.
    // The PCI Data Structure must be DWORD aligned.
    //
    if (OffsetPcir == 0 ||
        (OffsetPcir & 3) != 0 ||
        RomImageSize + OffsetPcir + sizeof (PCI_DATA_STRUCTURE) > RomSize) {
      break;
    }
    PciDevice->PciRootBridgeIo->Mem.Read (
                                      PciDevice->PciRootBridgeIo,
                                      EfiPciWidthUint8,
                                      RomBarOffset + OffsetPcir,
                                      sizeof (PCI_DATA_STRUCTURE),
                                      (UINT8 *) RomPcir
                                      );
    //
    // If a valid signature is not present in the PCI Data Structure, no further images can be located.
    //
    if (RomPcir->Signature != PCI_DATA_STRUCTURE_SIGNATURE) {
      break;
    }
    if (RomImageSize + RomPcir->ImageLength * 512 > RomSize) {
      break;
    }
    if (RomPcir->CodeType == PCI_CODE_TYPE_PCAT_IMAGE) {
      CodeType = PCI_CODE_TYPE_PCAT_IMAGE;
      LegacyImageLength = ((UINT32)((EFI_LEGACY_EXPANSION_ROM_HEADER *)RomHeader)->Size512) * 512;
    }
    Indicator     = RomPcir->Indicator;
    RomImageSize  = RomImageSize + RomPcir->ImageLength * 512;
    RomBarOffset  = RomBarOffset + RomPcir->ImageLength * 512;
  } while (((Indicator & 0x80) == 0x00) && ((RomBarOffset - RomBar) < RomSize));

  //
  // Some Legacy Cards do not report the correct ImageLength so used the maximum
  // of the legacy length and the PCIR Image Length
  //
  if (CodeType == PCI_CODE_TYPE_PCAT_IMAGE) {
    RomImageSize = MAX (RomImageSize, LegacyImageLength);
  }

  if (RomImageSize > 0) {
    RetStatus = EFI_SUCCESS;
    Image     = AllocatePool ((UINT32) RomImageSize);
    if (Image == NULL) {
      RomDecode (PciDevice, RomBarIndex, RomBar, FALSE);
      FreePool(RomHeader);
      FreePool(RomPcir);
      return EFI_OUT_OF_RESOURCES;
    }

    //
    // Copy Rom image into memory
    //
    PciDevice->PciRootBridgeIo->Mem.Read (
                                      PciDevice->PciRootBridgeIo,
                                      EfiPciWidthUint8,
                                      RomBar,
                                      (UINT32) RomImageSize,
                                      Image
                                      );
    RomInMemory = Image;
  }

  RomDecode (PciDevice, RomBarIndex, RomBar, FALSE);

  PciDevice->EmbeddedRom    = TRUE;
  PciDevice->PciIo.RomSize  = RomImageSize;
  PciDevice->PciIo.RomImage = RomInMemory;

  //
  // For OpROM read from PCI device:
  //   Add the Rom Image to internal database for later PCI light enumeration
  //
  PciRomAddImageMapping (
    NULL,
    PciDevice->PciRootBridgeIo->SegmentNumber,
    PciDevice->BusNumber,
    PciDevice->DeviceNumber,
    PciDevice->FunctionNumber,
    PciDevice->PciIo.RomImage,
    PciDevice->PciIo.RomSize
    );

  //
  // Free allocated memory
  //
  FreePool(RomHeader);
  FreePool(RomPcir);

  return RetStatus;
}

/**
  Enable/Disable Option Rom decode.

  @param PciDevice    Pci device instance.
  @param RomBarIndex  The BAR index of the standard PCI Configuration header to use as the
                      base address for resource range. The legal range for this field is 0..5.
  @param RomBar       Base address of Option Rom.
  @param Enable       Flag for enable/disable decode.

**/
VOID
RomDecode (
  IN PCI_IO_DEVICE   *PciDevice,
  IN UINT8           RomBarIndex,
  IN UINT32          RomBar,
  IN BOOLEAN         Enable
  )
{
  UINT32              Value32;
  EFI_PCI_IO_PROTOCOL *PciIo;

  PciIo = &PciDevice->PciIo;
  if (Enable) {

    //
    // set the Rom base address: now is hardcode
    // enable its decoder
    //
    Value32 = RomBar | 0x1;
    PciIo->Pci.Write (
                 PciIo,
                 (EFI_PCI_IO_PROTOCOL_WIDTH) EfiPciWidthUint32,
                 RomBarIndex,
                 1,
                 &Value32
                 );

    //
    // Programe all upstream bridge
    //
    ProgramUpstreamBridgeForRom (PciDevice, RomBar, TRUE);

    //
    // Setting the memory space bit in the function's command register
    //
    PCI_ENABLE_COMMAND_REGISTER(PciDevice, EFI_PCI_COMMAND_MEMORY_SPACE);

  } else {

    //
    // disable command register decode to memory
    //
    PCI_DISABLE_COMMAND_REGISTER(PciDevice, EFI_PCI_COMMAND_MEMORY_SPACE);

    //
    // Destroy the programmed bar in all the upstream bridge.
    //
    ProgramUpstreamBridgeForRom (PciDevice, RomBar, FALSE);

    //
    // disable rom decode
    //
    Value32 = 0xFFFFFFFE;
    PciIo->Pci.Write (
                 PciIo,
                 (EFI_PCI_IO_PROTOCOL_WIDTH) EfiPciWidthUint32,
                 RomBarIndex,
                 1,
                 &Value32
                 );

  }
}

/**
  Load and start the Option Rom image.

  @param PciDevice       Pci device instance.

  @retval EFI_SUCCESS    Successfully loaded and started PCI Option Rom image.
  @retval EFI_NOT_FOUND  Failed to process PCI Option Rom image.

**/
EFI_STATUS
ProcessOpRomImage (
  IN  PCI_IO_DEVICE   *PciDevice
  )
{
  UINT8                                    Indicator;
  UINT32                                   ImageSize;
  VOID                                     *RomBar;
  UINT8                                    *RomBarOffset;
  EFI_HANDLE                               ImageHandle;
  EFI_STATUS                               Status;
  EFI_STATUS                               RetStatus;
  EFI_PCI_EXPANSION_ROM_HEADER             *EfiRomHeader;
  PCI_DATA_STRUCTURE                       *Pcir;
  EFI_DEVICE_PATH_PROTOCOL                 *PciOptionRomImageDevicePath;
  MEDIA_RELATIVE_OFFSET_RANGE_DEVICE_PATH  EfiOpRomImageNode;
  VOID                                     *Buffer;
  UINTN                                    BufferSize;

  Indicator = 0;

  //
  // Get the Address of the Option Rom image
  //
  RomBar        = PciDevice->PciIo.RomImage;
  RomBarOffset  = (UINT8 *) RomBar;
  RetStatus     = EFI_NOT_FOUND;

  if (RomBar == NULL) {
    return RetStatus;
  }
  ASSERT (((EFI_PCI_EXPANSION_ROM_HEADER *) RomBarOffset)->Signature == PCI_EXPANSION_ROM_HEADER_SIGNATURE);

  do {
    EfiRomHeader = (EFI_PCI_EXPANSION_ROM_HEADER *) RomBarOffset;
    if (EfiRomHeader->Signature != PCI_EXPANSION_ROM_HEADER_SIGNATURE) {
      RomBarOffset += 512;
      continue;
    }

    Pcir        = (PCI_DATA_STRUCTURE *) (RomBarOffset + EfiRomHeader->PcirOffset);
    ASSERT (Pcir->Signature == PCI_DATA_STRUCTURE_SIGNATURE);
    ImageSize   = (UINT32) (Pcir->ImageLength * 512);
    Indicator   = Pcir->Indicator;

    //
    // Skip the image if it is not an EFI PCI Option ROM image
    //
    if (Pcir->CodeType != PCI_CODE_TYPE_EFI_IMAGE) {
      goto NextImage;
    }

    //
    // Ignore the EFI PCI Option ROM image if it is an EFI application
    //
    if (EfiRomHeader->EfiSubsystem == EFI_IMAGE_SUBSYSTEM_EFI_APPLICATION) {
      goto NextImage;
    }

    //
    // Create Pci Option Rom Image device path header
    //
    EfiOpRomImageNode.Header.Type     = MEDIA_DEVICE_PATH;
    EfiOpRomImageNode.Header.SubType  = MEDIA_RELATIVE_OFFSET_RANGE_DP;
    SetDevicePathNodeLength (&EfiOpRomImageNode.Header, sizeof (EfiOpRomImageNode));
    EfiOpRomImageNode.StartingOffset  = (UINTN) RomBarOffset - (UINTN) RomBar;
    EfiOpRomImageNode.EndingOffset    = (UINTN) RomBarOffset + ImageSize - 1 - (UINTN) RomBar;

    PciOptionRomImageDevicePath = AppendDevicePathNode (PciDevice->DevicePath, &EfiOpRomImageNode.Header);
    ASSERT (PciOptionRomImageDevicePath != NULL);

    //
    // load image and start image
    //
    BufferSize  = 0;
    Buffer      = NULL;
    ImageHandle = NULL;

    Status = gBS->LoadImage (
                    FALSE,
                    gPciBusDriverBinding.DriverBindingHandle,
                    PciOptionRomImageDevicePath,
                    Buffer,
                    BufferSize,
                    &ImageHandle
                    );
    if (EFI_ERROR(Status)) {
      //
      // Record the Option ROM Image device path when LoadImage fails.
      // PciOverride.GetDriver() will try to look for the Image Handle using the device path later.
      //
      AddDriver (PciDevice, NULL, PciOptionRomImageDevicePath);
    } else {
      Status = gBS->StartImage (ImageHandle, NULL, NULL);
      if (!EFI_ERROR(Status)) {
        //
        // Record the Option ROM Image Handle
        //
        AddDriver (PciDevice, ImageHandle, NULL);
        PciRomAddImageMapping (
          ImageHandle,
          PciDevice->PciRootBridgeIo->SegmentNumber,
          PciDevice->BusNumber,
          PciDevice->DeviceNumber,
          PciDevice->FunctionNumber,
          PciDevice->PciIo.RomImage,
          PciDevice->PciIo.RomSize
          );
        RetStatus = EFI_SUCCESS;
      }
    }
    FreePool(PciOptionRomImageDevicePath);

NextImage:
    RomBarOffset += ImageSize;

  } while (((Indicator & 0x80) == 0x00) && (((UINTN) RomBarOffset - (UINTN) RomBar) < PciDevice->RomSize));

  return RetStatus;
}