/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 *
 * Copyright (C) 2006 by Rani Hod
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define HEADER_SIZE 0x1030
#define FLASH_START        0x00010000
#define ROCKBOX_BOOTLOADER 0x00150000
#define BOOTLOADER_LIMIT   0x00170000 

void usage()
{
  printf("Usage: mkboot-x5 <firmware file> <boot file> <output file>\n");
}

void do_patch(char *fbuf, const char *bbuf, size_t blength)
{
  unsigned char *p;
  /* change jsr 0x10010 to jsr DUAL_BOOTLOADER */
  p = fbuf + HEADER_SIZE + 2;
  *p++ = (ROCKBOX_BOOTLOADER >> 24) & 0xff;
  *p++ = (ROCKBOX_BOOTLOADER >> 16) & 0xff;
  *p++ = (ROCKBOX_BOOTLOADER >>  8) & 0xff;
  *p++ = (ROCKBOX_BOOTLOADER      ) & 0xff;

  p = fbuf + HEADER_SIZE + ROCKBOX_BOOTLOADER - FLASH_START;
  memcpy(p, bbuf, blength);
}

int main(int argc, char **argv)
{
  size_t flength, blength;
  unsigned char *bbuf, *fbuf;
  const unsigned char fsig[] = { 
    /* jsr 10010 */
    0x4e, 0xb9, 0x00, 0x01, 0x00, 0x10 };
  const unsigned char bsig[] = { 
    /* tst.b 30000000 */
    0x4a, 0x39, 0x30, 0x00, 0x00, 0x00 };
  const char *fname, *bname, *oname;
  FILE *ffile, *bfile, *ofile;
  unsigned char sum = 0;
  int i;

  if (argc != 4)
  {
    usage();
    return 1;
  }
  fname = argv[1];
  bname = argv[2];
  oname = argv[3];

  /* read input files */
  if ((bfile = fopen(bname, "rb")) == NULL)
  {
    perror("Cannot open Rockbox bootloader file.\n");
    return -1;
  }

  fseek(bfile, 0, SEEK_END);
  blength = ftell(bfile);
  fseek(bfile, 0, SEEK_SET);

  if (blength + ROCKBOX_BOOTLOADER >= BOOTLOADER_LIMIT)
  {
    perror("Rockbox bootloader is too big.\n");
    return -1;
  }
 
  if ((ffile = fopen(fname, "rb")) == NULL)
  {
    perror("Cannot open original firmware file.\n");
    return -1;
  }
  
  fseek(ffile, 0, SEEK_END);
  flength = ftell(ffile);
  fseek(ffile, 0, SEEK_SET);

  bbuf = malloc(blength);
  fbuf = malloc(flength);

  if (!bbuf || !fbuf)
  {
    perror("Out of memory.\n");
    return -1;
  }

  if (   fread(bbuf, 1, blength, bfile) < blength 
      || fread(fbuf, 1, flength, ffile) < flength)
  {
    perror("Read error.\n");
    return -1;
  }
  fclose(bfile);
  fclose(ffile);

  /* verify format of input files */
  if (blength < 0x10
      || memcmp(bbuf, bsig, sizeof(bsig)))
  {
    perror("Rockbox bootloader format error (is it bootloader.bin?).\n");
    return -1;
  }
  if (flength < 0x1030-0x10000+BOOTLOADER_LIMIT 
      || memcmp(fbuf+0x1030, fsig, sizeof(fsig)))
  {
    perror("Original firmware format error (is it x5_fw.bin?).\n");
    return -1;
  }

  /* verify firmware is not overrun */
  for (i = ROCKBOX_BOOTLOADER; i < BOOTLOADER_LIMIT; i++)
  {
    if (fbuf[0x1030-0x10000+i] != 0xff)
    {
      perror("Original firmware has grown too much.\n");
      return -1;
    }
  }

  do_patch(fbuf, bbuf, blength);

  /* recalc checksum */
  for (i = 0x1030; i < flength; i++)
    sum += fbuf[i];
  fbuf[0x102b] = sum;

  /* write output */
  if ((ofile = fopen(oname, "wb")) == NULL)
  {
    perror("Cannot open output file.\n");
    return -1;
  }
  if (fwrite(fbuf, 1, flength, ofile) < flength)
  {
    perror("Write error.\n");
    return -1;
  }
  fclose(ofile);
  free(bbuf);
  free(fbuf);
}