tools/lpcrc/lpcrc.c

   1 /*
   2  * Software License Agreement (BSD License)
   3  *
   4  * Copyright (c) 2010, Roel Verdult
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the copyright holders nor the
  15  * names of its contributors may be used to endorse or promote products
  16  * derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
  22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  24  *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  27  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  *
  29  */
  30
  31 #include <stdio.h>
  32 #include <stdint.h>
  33
  34 #define BLOCK_COUNT 7
  35 #define BLOCK_LENGTH 4
  36 #define BLOCK_TOTAL (BLOCK_COUNT*BLOCK_LENGTH)
  37
  38 typedef unsigned char byte_t;
  39
  40 int main(int argc, char *argv[])
  41 {
  42   FILE* pf;
  43   byte_t buf[BLOCK_TOTAL];
  44   uint32_t crc = 0;
  45   uint32_t block;
  46
  47   // Check for required arguments
  48   if (argc < 2)
  49   {
  50     printf("syntax: lpcrc <firmware.bin>\n");
  51     return 1;
  52   }
  53
  54   // Try to open the supplied firmware
  55   if ((pf = fopen(argv[1],"rb+")) == NULL)
  56   {
  57     printf("error: could not open file [%s] with write access\n",argv[1]);
  58     return 1;
  59   }
  60
  61   // Read out the data blocks used for crc calculation
  62   if (fread(buf,1,BLOCK_TOTAL,pf) != BLOCK_TOTAL)
  63   {
  64     printf("error: could not read required bytes\n");
  65     fclose(pf);
  66     return 1;
  67   }
  68
  69   // Compute the crc value
  70   for (block=0; block<BLOCK_COUNT; block++)
  71   {
  72     crc += *((uint32_t*)(buf+(block*BLOCK_LENGTH)));
  73   }
  74   crc = (~crc) + 1;
  75
  76   // Reposition the file stream indicator to switch between read and write
  77   if (fseek(pf,0,SEEK_CUR) != 0)
  78   {
  79     printf("error: could not switch from read to write mode\n");
  80     fclose(pf);
  81     return 1;
  82   }
  83
  84   // Write the crc back to the file
  85   if (fwrite((byte_t*)&crc,1,BLOCK_LENGTH,pf) != BLOCK_LENGTH)
  86   {
  87     printf("error: could not write crc back to file\n");
  88     fclose(pf);
  89     return 1;
  90   }
  91
  92   printf("succesfully updated crc to: %08x\n",crc);
  93   fclose(pf);
  94
  95   return 0;
  96 }
  97