path: root/EdkModulePkg/Universal/Disk/DiskIo/Dxe/diskio.c

/*++

Copyright (c) 2006, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

Module Name:

  DiskIo.c

Abstract:

  DiskIo driver that layers it's self on every Block IO protocol in the system.
  DiskIo converts a block oriented device to a byte oriented device.

  ReadDisk may have to do reads that are not aligned on sector boundaries.
  There are three cases:

    UnderRun - The first byte is not on a sector boundary or the read request is
               less than a sector in length.

    Aligned  - A read of N contiguous sectors.

    OverRun  - The last byte is not on a sector boundary.

--*/

#include "DiskIo.h"

//
// Prototypes
// Driver model protocol interface
//
EFI_STATUS
EFIAPI
DiskIoDriverBindingSupported (
  IN EFI_DRIVER_BINDING_PROTOCOL    *This,
  IN EFI_HANDLE                     ControllerHandle,
  IN EFI_DEVICE_PATH_PROTOCOL       *RemainingDevicePath
  );

EFI_STATUS
EFIAPI
DiskIoDriverBindingStart (
  IN EFI_DRIVER_BINDING_PROTOCOL    *This,
  IN EFI_HANDLE                     ControllerHandle,
  IN EFI_DEVICE_PATH_PROTOCOL       *RemainingDevicePath
  );

EFI_STATUS
EFIAPI
DiskIoDriverBindingStop (
  IN  EFI_DRIVER_BINDING_PROTOCOL    *This,
  IN  EFI_HANDLE                     ControllerHandle,
  IN  UINTN                          NumberOfChildren,
  IN  EFI_HANDLE                     *ChildHandleBuffer
  );

//
// Disk I/O Protocol Interface
//
EFI_STATUS
EFIAPI
DiskIoReadDisk (
  IN EFI_DISK_IO_PROTOCOL  *This,
  IN UINT32                MediaId,
  IN UINT64                Offset,
  IN UINTN                 BufferSize,
  OUT VOID                 *Buffer
  );

EFI_STATUS
EFIAPI
DiskIoWriteDisk (
  IN EFI_DISK_IO_PROTOCOL  *This,
  IN UINT32                MediaId,
  IN UINT64                Offset,
  IN UINTN                 BufferSize,
  IN VOID                  *Buffer
  );

EFI_DRIVER_BINDING_PROTOCOL gDiskIoDriverBinding = {
  DiskIoDriverBindingSupported,
  DiskIoDriverBindingStart,
  DiskIoDriverBindingStop,
  0x10,
  NULL,
  NULL
};

DISK_IO_PRIVATE_DATA        gDiskIoPrivateDataTemplate = {
  DISK_IO_PRIVATE_DATA_SIGNATURE,
  {
    EFI_DISK_IO_PROTOCOL_REVISION,
    DiskIoReadDisk,
    DiskIoWriteDisk
  },
  NULL
};

EFI_STATUS
EFIAPI
DiskIoDriverBindingSupported (
  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
  IN EFI_HANDLE                   ControllerHandle,
  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL
  )
/*++

  Routine Description:
    Test to see if this driver supports ControllerHandle. Any ControllerHandle
    than contains a BlockIo protocol can be supported.

  Arguments:
    This                - Protocol instance pointer.
    ControllerHandle    - Handle of device to test.
    RemainingDevicePath - Not used.

  Returns:
    EFI_SUCCESS         - This driver supports this device.
    EFI_ALREADY_STARTED - This driver is already running on this device.
    other               - This driver does not support this device.

--*/
{
  EFI_STATUS            Status;
  EFI_BLOCK_IO_PROTOCOL *BlockIo;
/*
  DEBUG_CODE_BEGIN
    UINT32  Bar;
    UINT32  Foo;
    UINT32  HotPlug;

    //
    // Get TYPE 0
    //
    Bar = PcdGet32 (PciExpressBaseVersion);
    DEBUG ((EFI_D_ERROR, "PciExpressBaseVersion = %08x\n", Bar));

    //
    // Get TYPE 1
    //
    Foo = PcdGet32 (PciExpressBaseAddress);
    DEBUG ((EFI_D_ERROR, "PciExpressBaseAddress = %08x\n", Foo));

    //
    // Set TYPE 1
    //
    PcdSet32 (PciExpressBaseAddress, Foo + 1);

    //
    // Get TYPE 1
    //
    Foo = PcdGet32 (PciExpressBaseAddress);
    DEBUG ((EFI_D_ERROR, "PciExpressBaseAddress = %08x\n", Foo));

    //
    // Get TYPE 2
    //
    HotPlug = PcdGet32 (PciExpressBaseHotPlug);
    DEBUG ((EFI_D_ERROR, "PciExpressHotPlug = %08x\n", HotPlug));

    //
    // Set TYPE 1
    //
    PcdSet32 (PciExpressBaseHotPlug, HotPlug + 1);

    //
    // Get TYPE 1
    //
    HotPlug = PcdGet32 (PciExpressBaseHotPlug);
    DEBUG ((EFI_D_ERROR, "PciExpressHotPlug = %08x\n", HotPlug));

  DEBUG_CODE_END

  DEBUG_CODE_BEGIN
    UINT32  MyVariable;

    if (ControllerHandle == NULL) {
      MyVariable = 32 * (UINTN)This;
      ControllerHandle = (EFI_HANDLE)MyVariable;
      DEBUG ((EFI_D_ERROR, "DiskIoSupported-DebugCode.  MyVariable = %08x\n", MyVariable));
      ASSERT (MyVariable != 32);
    }
  DEBUG_CODE_END
*/
  DEBUG ((EFI_D_ERROR, "DiskIoSupported\n"));

//  Io8Or (0x400, 1);
//  Io8And (0x400, 1);
//  Io8AndThenOr (0x400, 1, 2);

//  Mmio8Or (0xa0000000, 1);
//  Mmio8And (0xa0000000, 1);
//  Mmio8AndThenOr (0xa0000000, 1, 2);

/*
  PciRead8   (PCI_LIB_ADDRESS (1,2,3,4));
  PciRead16  (PCI_LIB_ADDRESS (1,2,3,4));
  PciRead32  (PCI_LIB_ADDRESS (1,2,3,4));

  PciWrite8  (PCI_LIB_ADDRESS (1,2,3,4), 0xAA);
  PciWrite16 (PCI_LIB_ADDRESS (1,2,3,4), 0xAA55);
  PciWrite32 (PCI_LIB_ADDRESS (1,2,3,4), 0xAA55A55A);

  Pci8Or         (PCI_LIB_ADDRESS (1,2,3,4), 0xAA);
  Pci8And        (PCI_LIB_ADDRESS (1,2,3,4), 0x55);
  Pci8AndThenOr  (PCI_LIB_ADDRESS (1,2,3,4), 0xAA, 0x55);

  Pci16Or        (PCI_LIB_ADDRESS (1,2,3,4), 0xAA55);
  Pci16And       (PCI_LIB_ADDRESS (1,2,3,4), 0x55AA);
  Pci16AndThenOr (PCI_LIB_ADDRESS (1,2,3,4), 0xAA55, 0x55AA);

  Pci32Or        (PCI_LIB_ADDRESS (1,2,3,4), 0xAA55A55A);
  Pci32And       (PCI_LIB_ADDRESS (1,2,3,4), 0x55AA5AA5);
  Pci32AndThenOr (PCI_LIB_ADDRESS (1,2,3,4), 0xAA555AA5, 0x55AAA55A);
*/
  //
  // Open the IO Abstraction(s) needed to perform the supported test.
  //
  Status = gBS->OpenProtocol (
                  ControllerHandle,
                  &gEfiBlockIoProtocolGuid,
                  (VOID **) &BlockIo,
                  This->DriverBindingHandle,
                  ControllerHandle,
                  EFI_OPEN_PROTOCOL_BY_DRIVER
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Close the I/O Abstraction(s) used to perform the supported test.
  //
  gBS->CloseProtocol (
        ControllerHandle,
        &gEfiBlockIoProtocolGuid,
        This->DriverBindingHandle,
        ControllerHandle
        );
  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
DiskIoDriverBindingStart (
  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
  IN EFI_HANDLE                   ControllerHandle,
  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL
  )
/*++

  Routine Description:
    Start this driver on ControllerHandle by opening a Block IO protocol and
    installing a Disk IO protocol on ControllerHandle.

  Arguments:
    This                - Protocol instance pointer.
    ControllerHandle    - Handle of device to bind driver to.
    RemainingDevicePath - Not used, always produce all possible children.

  Returns:
    EFI_SUCCESS         - This driver is added to ControllerHandle.
    EFI_ALREADY_STARTED - This driver is already running on ControllerHandle.
    other               - This driver does not support this device.

--*/
{
  EFI_STATUS            Status;
  DISK_IO_PRIVATE_DATA  *Private;

  Private = NULL;

  DEBUG ((EFI_D_ERROR, "DiskIoStart\n"));
  //
  // Connect to the Block IO interface on ControllerHandle.
  //
  Status = gBS->OpenProtocol (
                  ControllerHandle,
                  &gEfiBlockIoProtocolGuid,
                  (VOID **) &gDiskIoPrivateDataTemplate.BlockIo,
                  This->DriverBindingHandle,
                  ControllerHandle,
                  EFI_OPEN_PROTOCOL_BY_DRIVER
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Initialize the Disk IO device instance.
  //
  Private = AllocateCopyPool (sizeof (DISK_IO_PRIVATE_DATA), &gDiskIoPrivateDataTemplate);
  if (Private == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ErrorExit;
  }
  //
  // Install protocol interfaces for the Disk IO device.
  //
  Status = gBS->InstallProtocolInterface (
                  &ControllerHandle,
                  &gEfiDiskIoProtocolGuid,
                  EFI_NATIVE_INTERFACE,
                  &Private->DiskIo
                  );

ErrorExit:
  if (EFI_ERROR (Status)) {

    if (Private != NULL) {
      gBS->FreePool (Private);
    }

    gBS->CloseProtocol (
          ControllerHandle,
          &gEfiBlockIoProtocolGuid,
          This->DriverBindingHandle,
          ControllerHandle
          );
  }

  return Status;
}

EFI_STATUS
EFIAPI
DiskIoDriverBindingStop (
  IN  EFI_DRIVER_BINDING_PROTOCOL    *This,
  IN  EFI_HANDLE                     ControllerHandle,
  IN  UINTN                          NumberOfChildren,
  IN  EFI_HANDLE                     *ChildHandleBuffer
  )
/*++

  Routine Description:
    Stop this driver on ControllerHandle by removing Disk IO protocol and closing
    the Block IO protocol on ControllerHandle.

  Arguments:
    This              - Protocol instance pointer.
    ControllerHandle  - Handle of device to stop driver on.
    NumberOfChildren  - Not used.
    ChildHandleBuffer - Not used.

  Returns:
    EFI_SUCCESS         - This driver is removed ControllerHandle.
    other               - This driver was not removed from this device.
    EFI_UNSUPPORTED

--*/
{
  EFI_STATUS            Status;
  EFI_DISK_IO_PROTOCOL  *DiskIo;
  DISK_IO_PRIVATE_DATA  *Private;

  DEBUG ((EFI_D_ERROR, "DiskIoStop\n"));
  //
  // Get our context back.
  //
  Status = gBS->OpenProtocol (
                  ControllerHandle,
                  &gEfiDiskIoProtocolGuid,
                  (VOID **) &DiskIo,
                  This->DriverBindingHandle,
                  ControllerHandle,
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL
                  );
  if (EFI_ERROR (Status)) {
    return EFI_UNSUPPORTED;
  }

  Private = DISK_IO_PRIVATE_DATA_FROM_THIS (DiskIo);

  Status = gBS->UninstallProtocolInterface (
                  ControllerHandle,
                  &gEfiDiskIoProtocolGuid,
                  &Private->DiskIo
                  );
  if (!EFI_ERROR (Status)) {

    Status = gBS->CloseProtocol (
                    ControllerHandle,
                    &gEfiBlockIoProtocolGuid,
                    This->DriverBindingHandle,
                    ControllerHandle
                    );
  }

  if (!EFI_ERROR (Status)) {
    gBS->FreePool (Private);
  }

  return Status;
}

EFI_STATUS
EFIAPI
DiskIoReadDisk (
  IN EFI_DISK_IO_PROTOCOL  *This,
  IN UINT32                MediaId,
  IN UINT64                Offset,
  IN UINTN                 BufferSize,
  OUT VOID                 *Buffer
  )
/*++

  Routine Description:
    Read BufferSize bytes from Offset into Buffer.

    Reads may support reads that are not aligned on
    sector boundaries. There are three cases:

      UnderRun - The first byte is not on a sector boundary or the read request is
                 less than a sector in length.

      Aligned  - A read of N contiguous sectors.

      OverRun  - The last byte is not on a sector boundary.


  Arguments:
    This       - Protocol instance pointer.
    MediaId    - Id of the media, changes every time the media is replaced.
    Offset     - The starting byte offset to read from.
    BufferSize - Size of Buffer.
    Buffer     - Buffer containing read data.

  Returns:
    EFI_SUCCESS           - The data was read correctly from the device.
    EFI_DEVICE_ERROR      - The device reported an error while performing the read.
    EFI_NO_MEDIA          - There is no media in the device.
    EFI_MEDIA_CHNAGED     - The MediaId does not matched the current device.
    EFI_INVALID_PARAMETER - The read request contains device addresses that are not
                            valid for the device.
    EFI_OUT_OF_RESOURCES

--*/
{
  EFI_STATUS            Status;
  DISK_IO_PRIVATE_DATA  *Private;
  EFI_BLOCK_IO_PROTOCOL *BlockIo;
  EFI_BLOCK_IO_MEDIA    *Media;
  UINT32                BlockSize;
  UINT64                Lba;
  UINT64                OverRunLba;
  UINT32                UnderRun;
  UINT32                OverRun;
  BOOLEAN               TransactionComplete;
  UINTN                 WorkingBufferSize;
  UINT8                 *WorkingBuffer;
  UINTN                 Length;
  UINT8                 *Data;
  UINT8                 *PreData;
  UINTN                 IsBufferAligned;
  UINTN                 DataBufferSize;
  BOOLEAN               LastRead;

  DEBUG ((EFI_D_ERROR, "DiskIoReadDisk\n"));

  Private   = DISK_IO_PRIVATE_DATA_FROM_THIS (This);

  BlockIo   = Private->BlockIo;
  Media     = BlockIo->Media;
  BlockSize = Media->BlockSize;

  if (Media->MediaId != MediaId) {
    return EFI_MEDIA_CHANGED;
  }

  WorkingBuffer     = Buffer;
  WorkingBufferSize = BufferSize;

  //
  // Allocate a temporary buffer for operation
  //
  DataBufferSize = BlockSize * DATA_BUFFER_BLOCK_NUM;

  if (Media->IoAlign > 1) {
    PreData = AllocatePool (DataBufferSize + Media->IoAlign);
    Data    = PreData - ((UINTN) PreData & (Media->IoAlign - 1)) + Media->IoAlign;
  } else {
    PreData = AllocatePool (DataBufferSize);
    Data    = PreData;
  }

  if (PreData == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Lba                 = DivU64x32Remainder (Offset, BlockSize, &UnderRun);

  Length              = BlockSize - UnderRun;
  TransactionComplete = FALSE;

  Status              = EFI_SUCCESS;
  if (UnderRun != 0) {
    //
    // Offset starts in the middle of an Lba, so read the entire block.
    //
    Status = BlockIo->ReadBlocks (
                        BlockIo,
                        MediaId,
                        Lba,
                        BlockSize,
                        Data
                        );

    if (EFI_ERROR (Status)) {
      goto Done;
    }

    if (Length > BufferSize) {
      Length              = BufferSize;
      TransactionComplete = TRUE;
    }

    CopyMem (WorkingBuffer, Data + UnderRun, Length);

    WorkingBuffer += Length;

    WorkingBufferSize -= Length;
    if (WorkingBufferSize == 0) {
      goto Done;
    }

    Lba += 1;
  }

  OverRunLba = Lba + DivU64x32Remainder (WorkingBufferSize, BlockSize, &OverRun);

  if (!TransactionComplete && WorkingBufferSize >= BlockSize) {
    //
    // If the DiskIo maps directly to a BlockIo device do the read.
    //
    if (OverRun != 0) {
      WorkingBufferSize -= OverRun;
    }
    //
    // Check buffer alignment
    //
    IsBufferAligned = (UINTN) WorkingBuffer & (UINTN) (Media->IoAlign - 1);

    if (Media->IoAlign <= 1 || IsBufferAligned == 0) {
      //
      // Alignment is satisfied, so read them together
      //
      Status = BlockIo->ReadBlocks (
                          BlockIo,
                          MediaId,
                          Lba,
                          WorkingBufferSize,
                          WorkingBuffer
                          );

      if (EFI_ERROR (Status)) {
        goto Done;
      }

      WorkingBuffer += WorkingBufferSize;

    } else {
      //
      // Use the allocated buffer instead of the original buffer
      // to avoid alignment issue.
      // Here, the allocated buffer (8-byte align) can satisfy the alignment
      //
      LastRead = FALSE;
      do {
        if (WorkingBufferSize <= DataBufferSize) {
          //
          // It is the last calling to readblocks in this loop
          //
          DataBufferSize  = WorkingBufferSize;
          LastRead        = TRUE;
        }

        Status = BlockIo->ReadBlocks (
                            BlockIo,
                            MediaId,
                            Lba,
                            DataBufferSize,
                            Data
                            );
        if (EFI_ERROR (Status)) {
          goto Done;
        }

        CopyMem (WorkingBuffer, Data, DataBufferSize);
        WorkingBufferSize -= DataBufferSize;
        WorkingBuffer += DataBufferSize;
        Lba += DATA_BUFFER_BLOCK_NUM;
      } while (!LastRead);
    }
  }

  if (!TransactionComplete && OverRun != 0) {
    //
    // Last read is not a complete block.
    //
    Status = BlockIo->ReadBlocks (
                        BlockIo,
                        MediaId,
                        OverRunLba,
                        BlockSize,
                        Data
                        );

    if (EFI_ERROR (Status)) {
      goto Done;
    }

    CopyMem (WorkingBuffer, Data, OverRun);
  }

Done:
  if (PreData != NULL) {
    gBS->FreePool (PreData);
  }

  return Status;
}

EFI_STATUS
EFIAPI
DiskIoWriteDisk (
  IN EFI_DISK_IO_PROTOCOL  *This,
  IN UINT32                MediaId,
  IN UINT64                Offset,
  IN UINTN                 BufferSize,
  IN VOID                  *Buffer
  )
/*++

  Routine Description:
    Read BufferSize bytes from Offset into Buffer.

    Writes may require a read modify write to support writes that are not
    aligned on sector boundaries. There are three cases:

      UnderRun - The first byte is not on a sector boundary or the write request
                 is less than a sector in length. Read modify write is required.

      Aligned  - A write of N contiguous sectors.

      OverRun  - The last byte is not on a sector boundary. Read modified write
                 required.

  Arguments:
    This       - Protocol instance pointer.
    MediaId    - Id of the media, changes every time the media is replaced.
    Offset     - The starting byte offset to read from.
    BufferSize - Size of Buffer.
    Buffer     - Buffer containing read data.

  Returns:
    EFI_SUCCESS           - The data was written correctly to the device.
    EFI_WRITE_PROTECTED   - The device can not be written to.
    EFI_DEVICE_ERROR      - The device reported an error while performing the write.
    EFI_NO_MEDIA          - There is no media in the device.
    EFI_MEDIA_CHNAGED     - The MediaId does not matched the current device.
    EFI_INVALID_PARAMETER - The write request contains device addresses that are not
                            valid for the device.
    EFI_OUT_OF_RESOURCES

--*/
{
  EFI_STATUS            Status;
  DISK_IO_PRIVATE_DATA  *Private;
  EFI_BLOCK_IO_PROTOCOL *BlockIo;
  EFI_BLOCK_IO_MEDIA    *Media;
  UINT32                BlockSize;
  UINT64                Lba;
  UINT64                OverRunLba;
  UINT32                UnderRun;
  UINT32                OverRun;
  BOOLEAN               TransactionComplete;
  UINTN                 WorkingBufferSize;
  UINT8                 *WorkingBuffer;
  UINTN                 Length;
  UINT8                 *Data;
  UINT8                 *PreData;
  UINTN                 IsBufferAligned;
  UINTN                 DataBufferSize;
  BOOLEAN               LastWrite;

  DEBUG ((EFI_D_ERROR, "DiskIoWriteDisk\n"));

  Private   = DISK_IO_PRIVATE_DATA_FROM_THIS (This);

  BlockIo   = Private->BlockIo;
  Media     = BlockIo->Media;
  BlockSize = Media->BlockSize;

  if (Media->ReadOnly) {
    return EFI_WRITE_PROTECTED;
  }

  if (Media->MediaId != MediaId) {
    return EFI_MEDIA_CHANGED;
  }

  DataBufferSize = BlockSize * DATA_BUFFER_BLOCK_NUM;

  if (Media->IoAlign > 1) {
    PreData = AllocatePool (DataBufferSize + Media->IoAlign);
    Data    = PreData - ((UINTN) PreData & (Media->IoAlign - 1)) + Media->IoAlign;
  } else {
    PreData = AllocatePool (DataBufferSize);
    Data    = PreData;
  }

  if (PreData == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  WorkingBuffer       = Buffer;
  WorkingBufferSize   = BufferSize;

  Lba                 = DivU64x32Remainder (Offset, BlockSize, &UnderRun);

  Length              = BlockSize - UnderRun;
  TransactionComplete = FALSE;

  Status              = EFI_SUCCESS;
  if (UnderRun != 0) {
    //
    // Offset starts in the middle of an Lba, so do read modify write.
    //
    Status = BlockIo->ReadBlocks (
                        BlockIo,
                        MediaId,
                        Lba,
                        BlockSize,
                        Data
                        );

    if (EFI_ERROR (Status)) {
      goto Done;
    }

    if (Length > BufferSize) {
      Length              = BufferSize;
      TransactionComplete = TRUE;
    }

    CopyMem (Data + UnderRun, WorkingBuffer, Length);

    Status = BlockIo->WriteBlocks (
                        BlockIo,
                        MediaId,
                        Lba,
                        BlockSize,
                        Data
                        );
    if (EFI_ERROR (Status)) {
      goto Done;
    }

    WorkingBuffer += Length;
    WorkingBufferSize -= Length;
    if (WorkingBufferSize == 0) {
      goto Done;
    }

    Lba += 1;
  }

  OverRunLba = Lba + DivU64x32Remainder (WorkingBufferSize, BlockSize, &OverRun);

  if (!TransactionComplete && WorkingBufferSize >= BlockSize) {
    //
    // If the DiskIo maps directly to a BlockIo device do the write.
    //
    if (OverRun != 0) {
      WorkingBufferSize -= OverRun;
    }
    //
    // Check buffer alignment
    //
    IsBufferAligned = (UINTN) WorkingBuffer & (UINTN) (Media->IoAlign - 1);

    if (Media->IoAlign <= 1 || IsBufferAligned == 0) {
      //
      // Alignment is satisfied, so write them together
      //
      Status = BlockIo->WriteBlocks (
                          BlockIo,
                          MediaId,
                          Lba,
                          WorkingBufferSize,
                          WorkingBuffer
                          );

      if (EFI_ERROR (Status)) {
        goto Done;
      }

      WorkingBuffer += WorkingBufferSize;

    } else {
      //
      // The buffer parameter is not aligned with the request
      // So use the allocated instead.
      // It can fit almost all the cases.
      //
      LastWrite = FALSE;
      do {
        if (WorkingBufferSize <= DataBufferSize) {
          //
          // It is the last calling to writeblocks in this loop
          //
          DataBufferSize  = WorkingBufferSize;
          LastWrite       = TRUE;
        }

        CopyMem (Data, WorkingBuffer, DataBufferSize);
        Status = BlockIo->WriteBlocks (
                            BlockIo,
                            MediaId,
                            Lba,
                            DataBufferSize,
                            Data
                            );
        if (EFI_ERROR (Status)) {
          goto Done;
        }

        WorkingBufferSize -= DataBufferSize;
        WorkingBuffer += DataBufferSize;
        Lba += DATA_BUFFER_BLOCK_NUM;
      } while (!LastWrite);
    }
  }

  if (!TransactionComplete && OverRun != 0) {
    //
    // Last bit is not a complete block, so do a read modify write.
    //
    Status = BlockIo->ReadBlocks (
                        BlockIo,
                        MediaId,
                        OverRunLba,
                        BlockSize,
                        Data
                        );

    if (EFI_ERROR (Status)) {
      goto Done;
    }

    CopyMem (Data, WorkingBuffer, OverRun);

    Status = BlockIo->WriteBlocks (
                        BlockIo,
                        MediaId,
                        OverRunLba,
                        BlockSize,
                        Data
                        );
    if (EFI_ERROR (Status)) {
      goto Done;
    }
  }

Done:
  if (PreData != NULL) {
    gBS->FreePool (PreData);
  }

  return Status;
}