Add comments and DoxyGen format for these files.

[mirror_edk2.git] / MdeModulePkg / Core / Dxe / FwVol / Ffs.c

/** @file \r
\r
  FFS file access utilities.\r
\r
Copyright (c) 2006 - 2008, Intel Corporation                                                         \r
All rights reserved. This program and the accompanying materials                          \r
are licensed and made available under the terms and conditions of the BSD License         \r
which accompanies this distribution.  The full text of the license may be found at        \r
http://opensource.org/licenses/bsd-license.php                                            \r
                                                                                          \r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     \r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             \r
\r
**/\r
\r
\r
#include <DxeMain.h>\r
\r
#define PHYSICAL_ADDRESS_TO_POINTER(Address) ((VOID *)((UINTN)(Address)))\r
\r
\r
EFI_FFS_FILE_STATE\r
GetFileState (\r
  IN UINT8                ErasePolarity,\r
  IN EFI_FFS_FILE_HEADER  *FfsHeader\r
  )\r
/*++\r
\r
Routine Description:\r
  Get the FFS file state by checking the highest bit set in the header's state field\r
\r
Arguments:\r
  ErasePolarity -  Erase polarity attribute of the firmware volume\r
  FfsHeader     -  Points to the FFS file header\r
    \r
Returns:\r
  FFS File state \r
    \r
--*/\r
{\r
  EFI_FFS_FILE_STATE      FileState;\r
  UINT8                   HighestBit;\r
\r
  FileState = FfsHeader->State;\r
\r
  if (ErasePolarity != 0) {\r
    FileState = (EFI_FFS_FILE_STATE)~FileState;\r
  }\r
\r
  HighestBit = 0x80;\r
  while (HighestBit != 0 && ((HighestBit & FileState) == 0)) {\r
    HighestBit >>= 1;\r
  }\r
\r
  return (EFI_FFS_FILE_STATE)HighestBit;\r
}\r
\r
\r
BOOLEAN\r
IsBufferErased (\r
  IN UINT8    ErasePolarity,\r
  IN VOID     *InBuffer,\r
  IN UINTN    BufferSize\r
  )\r
/*++\r
\r
Routine Description:\r
  Check if a block of buffer is erased\r
\r
Arguments:\r
  ErasePolarity -  Erase polarity attribute of the firmware volume\r
  InBuffer      -  The buffer to be checked\r
  BufferSize    -  Size of the buffer in bytes\r
    \r
Returns:\r
  TRUE  -  The block of buffer is erased\r
  FALSE -  The block of buffer is not erased\r
    \r
--*/\r
{\r
  UINTN   Count;\r
  UINT8   EraseByte;\r
  UINT8   *Buffer;\r
\r
  if(ErasePolarity == 1) {\r
    EraseByte = 0xFF;\r
  } else {\r
    EraseByte = 0;\r
  }\r
\r
  Buffer = InBuffer;\r
  for (Count = 0; Count < BufferSize; Count++) {\r
    if (Buffer[Count] != EraseByte) {\r
      return FALSE;\r
    }\r
  }\r
\r
  return TRUE;\r
}\r
\r
\r
BOOLEAN\r
VerifyFvHeaderChecksum (\r
  IN EFI_FIRMWARE_VOLUME_HEADER *FvHeader\r
  )\r
/*++\r
\r
Routine Description:\r
  Verify checksum of the firmware volume header \r
\r
Arguments:\r
  FvHeader  -  Points to the firmware volume header to be checked\r
    \r
Returns:\r
  TRUE  -  Checksum verification passed\r
  FALSE -  Checksum verification failed\r
    \r
--*/\r
{\r
  UINT32  Index;\r
  UINT32  HeaderLength;\r
  UINT16  Checksum;\r
  UINT16  *ptr;\r
\r
  HeaderLength = FvHeader->HeaderLength;\r
  ptr = (UINT16 *)FvHeader;\r
  Checksum = 0;\r
\r
  for (Index = 0; Index < HeaderLength / sizeof (UINT16); Index++) {\r
    Checksum = (UINT16)(Checksum + ptr[Index]);\r
  }\r
\r
  if (Checksum == 0) {\r
    return TRUE;\r
  } else {\r
    return FALSE;\r
  }\r
}\r
\r
STATIC\r
BOOLEAN\r
VerifyHeaderChecksum (\r
  IN EFI_FFS_FILE_HEADER  *FfsHeader\r
  )\r
/*++\r
\r
Routine Description:\r
  Verify checksum of the FFS file header \r
\r
Arguments:\r
  FfsHeader  -  Points to the FFS file header to be checked\r
    \r
Returns:\r
  TRUE  -  Checksum verification passed\r
  FALSE -  Checksum verification failed\r
    \r
--*/\r
{\r
  UINT32            Index;\r
  UINT8             *ptr;\r
  UINT8             HeaderChecksum;\r
\r
  ptr = (UINT8 *)FfsHeader;\r
  HeaderChecksum = 0;\r
  for (Index = 0; Index < sizeof(EFI_FFS_FILE_HEADER); Index++) {\r
    HeaderChecksum = (UINT8)(HeaderChecksum + ptr[Index]);\r
  }\r
\r
  HeaderChecksum = (UINT8) (HeaderChecksum - FfsHeader->State - FfsHeader->IntegrityCheck.Checksum.File);\r
\r
  if (HeaderChecksum == 0) {\r
    return TRUE;\r
  } else {\r
    return FALSE;\r
  }\r
}\r
\r
\r
BOOLEAN\r
IsValidFfsHeader (\r
  IN UINT8                ErasePolarity,\r
  IN EFI_FFS_FILE_HEADER  *FfsHeader,\r
  OUT EFI_FFS_FILE_STATE  *FileState\r
  )\r
/*++\r
\r
Routine Description:\r
  Check if it's a valid FFS file header\r
\r
Arguments:\r
  ErasePolarity -  Erase polarity attribute of the firmware volume\r
  FfsHeader     -  Points to the FFS file header to be checked\r
  FileState     -  FFS file state to be returned\r
    \r
Returns:\r
  TRUE  -  Valid FFS file header\r
  FALSE -  Invalid FFS file header\r
    \r
--*/\r
{\r
  *FileState = GetFileState (ErasePolarity, FfsHeader);\r
\r
  switch (*FileState) {\r
    case EFI_FILE_HEADER_VALID:\r
    case EFI_FILE_DATA_VALID:\r
    case EFI_FILE_MARKED_FOR_UPDATE:\r
    case EFI_FILE_DELETED:\r
      //\r
      // Here we need to verify header checksum\r
      //\r
      return VerifyHeaderChecksum (FfsHeader);\r
    \r
    case EFI_FILE_HEADER_CONSTRUCTION:\r
    case EFI_FILE_HEADER_INVALID:\r
    default:\r
      return FALSE;\r
  }\r
}\r
\r
\r
BOOLEAN\r
IsValidFfsFile (\r
  IN UINT8                ErasePolarity,\r
  IN EFI_FFS_FILE_HEADER  *FfsHeader\r
  )\r
/*++\r
\r
Routine Description:\r
  Check if it's a valid FFS file. \r
  Here we are sure that it has a valid FFS file header since we must call IsValidFfsHeader() first.\r
\r
Arguments:\r
  ErasePolarity -  Erase polarity attribute of the firmware volume\r
  FfsHeader     -  Points to the FFS file to be checked\r
    \r
Returns:\r
  TRUE  -  Valid FFS file\r
  FALSE -  Invalid FFS file\r
    \r
--*/\r
{\r
  EFI_FFS_FILE_STATE  FileState;\r
\r
  FileState = GetFileState (ErasePolarity, FfsHeader);\r
  switch (FileState) {\r
\r
    case EFI_FILE_DELETED:\r
    case EFI_FILE_DATA_VALID:\r
    case EFI_FILE_MARKED_FOR_UPDATE:\r
      //\r
      // Some other vliadation like file content checksum might be done here.\r
      // For performance issue, Tiano only do FileState check.\r
      //\r
      return TRUE;\r
\r
    default:\r
      return FALSE;\r
  }\r
}\r
\r