/*
 * Cut (appart the) Z(aurus) ROM (Image)
 *
 * cutzrom.c - Version 1.0 - March 16, 2002
 * Mark T. Grennan - mark@grennan.com
 *
 * This file expects the input file ROMIMAGE
 */

/*
 * The  SL-5000  can  be  updated  either with a single "romimage" file 
 * or with individual files for the kernel, root filesystem and bootflag 
 * file (which specifies the initial filesystem).
 *
 * The  romimage  is  exactly  that  -  it  is a 16M file which is loaded 
 * more-or-less directly into the FLASH ROM. The layout is as follows
 *
 * offset	   length Name         Contents 
 * dec      hex
 * 0        0	   49688  BOOTSHP2.BIN Boot loader
 * 131072   020000 31740  CF.BIN       Flash update utility?
 * 262144   040000 513960 COLLIE.BIN   Hardware test utility?
 * 786432   0C0000 varies ZIMAGE       kernel
 * 1835008  1C0000 varies ROMDISK.BIN  Cramfs root filesystem image
 * 16695296 FEC000 4	  BOOTFLAG.TXT Specifies the initial run level.
 * 16728064 FF4000 24                  Text "SHARPSL-series"
 * 16744448 FF8000 224                 Directory block
 *
 * The directory block seems to be structured as follows
 *
 * 8 bytes filename
 * 3 bytes extension
 * 1 byte ? always 00
 * 2 byte ? varies
 * 2 bytes ? always 0xff
 * 8 bytes date in ASCII yyyymmdd
 * 4 bytes start offset in image
 * 4 bytes end offset in image + 1
 *
 * The actual directory in the 1.02 ROM image is as follows
 * 
 * 00ff8000: 424f 4f54 5348 5032 4249 4e00 a6d8 ffff  BOOTSHP2BIN.....
 * 00ff8010: 3230 3031 3130 3133 0000 0000 0000 0200  20011013........
 * 00ff8020: 4346 2020 2020 2020 4249 4e00 1ce4 ffff  CF      BIN.....
 * 00ff8030: 3230 3031 3130 3232 0000 0200 0000 0400  20011022........
 * 00ff8040: 434f 4c4c 4945 2020 4249 4e00 ea6c ffff  COLLIE  BIN..l..
 * 00ff8050: 3230 3031 3130 3133 0000 0400 0000 0c00  20011013........
 * 00ff8060: 5a49 4d41 4745 2020 2020 2000 c45c ffff  ZIMAGE     ..\..
 * 00ff8070: 3230 3031 3131 3038 0000 0c00 0000 1a00  20011108........
 * 00ff8080: 524f 4d44 4953 4b20 4249 4e00 d66c ffff  ROMDISK BIN..l..
 * 00ff8090: 3230 3031 3131 3232 0000 1c00 0000 cc00  20011122........
 * 00ff80a0: 454e 4420 2020 2020 2020 2000 0000 ffff  END        .....
 * 00ff80b0: 3139 3830 3030 3030 0000 0000 0000 0000  19800000........
 * 00ff80c0: 454c 4154 4520 2020 4249 4e00 0000 ffff  ELATE   BIN.....
 * 00ff80d0: 3139 3830 3033 3034 0000 0000 0100 0000  19800304........
 *
 * There  are  two  "files"  in  the  directory  block which don't appear 
 * to be in the image which are "END" and "ELATE.BIN" and the bootflags.txt 
 * file isn't in the directory, neither is there anything corresponding 
 * to the text at offset 0xFF4000.
 *
 * If  a given file is smaller than the space allocated for it then the 
 * image is padded with 0xFF bytes. The two files that vary the most in
 * size are the kernel and the root filesystem image.
 * 
 * One  problem with this layout is that half a megabyte is "wasted" by 
 * the "collie.bin" file. There is no documentation on this but looking  
 * at the  embedded  strings suggests that it is some sort of hardware 
 * diagnostics utility. Unfortunately although the directory contains 
 * start/end offsets for the files I doubt that they are actually movable. 
 * One boundary which is definately fixed is the start of the root 
 * filesystem image at 0x1C0000 since the kernel device driver has this 
 * address hard-wired in.
 *                               
 * Another  thing  which  is  apparent  is that it should be much safer 
 * to upgrade by copying zImage, initrd.bin and bootflag.txt as separate  
 * files to the CF card. Assuming that the flash utility will overwrite 
 * all of flash when upgrading from a single romimage file  then  it  is 
 * possible to corrupt the bootloader and/or the flash code (should, for 
 * example, the power fail). Upgrading from separate  files  should  not 
 * involve  overwriting any of the critical images so even if the Zarus 
 * won't boot after an upgrade it should always be possible to try again.
 *
 */

#include <stdio.h>

int main()
{
	FILE *fp1;
	FILE *fp2;
	long x;
	char d;

/* Write BOOTSHP2.BIN - Boot loader */
	printf("\nCreating BOOTSHP2.BIN\n");
	fp1 = fopen("ROMIMAGE", "r");
	fp2 = fopen("BOOTSHP2.BIN", "w");

	for(x=0; x<49688; x++)
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);

/* Write CF.BIN - Flash update utility */
	printf("Creating CF.BIN\n");
	fp2 = fopen("CF.BIN", "w");

	fseek( fp1, 0x020000, SEEK_SET);
	for(x=0; x<31740; x++)
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);


/* Write COLLIE.BIN -  Hardware test utility */
	printf("Creating COLLIE.BIN\n");
	fp2 = fopen("COLLIE.BIN", "w");

	fseek( fp1, 0x040000, SEEK_SET);
	for(x=0; x<513960; x++)
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);

/* Write  ZIMAGE - kernel */
	printf("Creating zImage\n");
	fp2 = fopen("zImage", "w");

	fseek( fp1, 0x0c0000, SEEK_SET);
	for(x=0; x<=0x0100000; x++)	/* lenth varies */
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);

/* Write  ROMDISK.BIN  Cramfs root filesystem image */
	printf("Creating ROMDISK.BIN\n");
	fp2 = fopen("ROMDISK.BIN", "w");

	fseek( fp1, 0x01c0000, SEEK_SET);
	for(x=0; x<=0x0e2c000; x++)	/* lenth varies */
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);

/* Write  BOOTFLAG.TXT Specifies the initial run level */
	printf("Creating BOOTFLAG.TXT\n");
	fp2 = fopen("BOOTFLAG.TXT", "w");

	fseek( fp1, 0x0fec000, SEEK_SET);
	for(x=0; x<=4; x++)
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);

/* Write  FILETYPE  Specifies the initial run level */
	printf("Creating FILETYPE\n");
	fp2 = fopen("FILETYPE.TXT", "w");

	fseek( fp1, 0x0ff4000, SEEK_SET);
	for(x=0; x<=24; x++)
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);

/* Write  DIRECTORY  Specifies the initial run level */
	printf("Creating DIRECTORY.BIN\n");
	fp2 = fopen("DIRECTORY.BIN", "w");

	fseek( fp1, 0x0ff8000, SEEK_SET);
	for(x=0; x<=244; x++)
	{
		fread(&d, 1, 1, fp1);
		fwrite(&d, 1,1, fp2);
	}

	fclose(fp2);
	fclose(fp1);

	exit(1);
}