EmbeddedPkg/Application/AndroidFastboot/AndroidBootImg.c

   1 /** @file
   2
   3   Copyright (c) 2013-2014, ARM Ltd. All rights reserved.<BR>
   4
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "AndroidFastbootApp.h"
  16
  17 #define BOOT_MAGIC        "ANDROID!"
  18 #define BOOT_MAGIC_LENGTH sizeof (BOOT_MAGIC) - 1
  19
  20 // Check Val (unsigned) is a power of 2 (has only one bit set)
  21 #define IS_POWER_OF_2(Val) (Val != 0 && ((Val & (Val - 1)) == 0))
  22
  23 // No documentation for this really - sizes of fields has been determined
  24 // empirically.
  25 #pragma pack(1)
  26 typedef struct {
  27   CHAR8   BootMagic[BOOT_MAGIC_LENGTH];
  28   UINT32  KernelSize;
  29   UINT32  KernelAddress;
  30   UINT32  RamdiskSize;
  31   UINT32  RamdiskAddress;
  32   UINT32  SecondStageBootloaderSize;
  33   UINT32  SecondStageBootloaderAddress;
  34   UINT32  KernelTaggsAddress;
  35   UINT32  PageSize;
  36   UINT32  Reserved[2];
  37   CHAR8   ProductName[16];
  38   CHAR8   KernelArgs[BOOTIMG_KERNEL_ARGS_SIZE];
  39   UINT32  Id[32];
  40 } ANDROID_BOOTIMG_HEADER;
  41 #pragma pack()
  42
  43 // Find the kernel and ramdisk in an Android boot.img.
  44 // return EFI_INVALID_PARAMTER if the boot.img is invalid (i.e. doesn't have the
  45 //  right magic value),
  46 // return EFI_NOT_FOUND if there was no kernel in the boot.img.
  47 // Note that the Ramdisk is optional - *Ramdisk won't be touched if it isn't
  48 // present, but RamdiskSize will be set to 0.
  49 EFI_STATUS
  50 ParseAndroidBootImg (
  51   IN  VOID    *BootImg,
  52   OUT VOID   **Kernel,
  53   OUT UINTN   *KernelSize,
  54   OUT VOID   **Ramdisk,
  55   OUT UINTN   *RamdiskSize,
  56   OUT CHAR8   *KernelArgs
  57   )
  58 {
  59   ANDROID_BOOTIMG_HEADER   *Header;
  60   UINT8                    *BootImgBytePtr;
  61
  62   // Cast to UINT8 so we can do pointer arithmetic
  63   BootImgBytePtr = (UINT8 *) BootImg;
  64
  65   Header = (ANDROID_BOOTIMG_HEADER *) BootImg;
  66
  67   if (AsciiStrnCmp (Header->BootMagic, BOOT_MAGIC, BOOT_MAGIC_LENGTH) != 0) {
  68     return EFI_INVALID_PARAMETER;
  69   }
  70
  71   if (Header->KernelSize == 0) {
  72     return EFI_NOT_FOUND;
  73   }
  74
  75   ASSERT (IS_POWER_OF_2 (Header->PageSize));
  76
  77   *KernelSize = Header->KernelSize;
  78   *Kernel = BootImgBytePtr + Header->PageSize;
  79   *RamdiskSize = Header->RamdiskSize;
  80
  81   if (Header->RamdiskSize != 0) {
  82     *Ramdisk = (VOID *) (BootImgBytePtr
  83                  + Header->PageSize
  84                  + ALIGN_VALUE (Header->KernelSize, Header->PageSize));
  85   }
  86
  87   AsciiStrnCpy (KernelArgs, Header->KernelArgs, BOOTIMG_KERNEL_ARGS_SIZE);
  88
  89   return EFI_SUCCESS;
  90 }