/* 
 *
 * $Id: fat.c,v 1.1.1.1 2002/08/28 16:10:51 salmoon Exp $
 *
 * Library for USB MPIO-*
 *
 * Markus Germeier (mager@tzi.de)
 *
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * */

#include "fat.h"
#include "io.h"
#include "debug.h"

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

int
mpio_bootblocks_read (mpio_t *m, mpio_mem_t mem)
{
  BYTE *pe;  /* partition entry */
  BYTE *bpb; /* BIOS Parameter Block */

  mpio_smartmedia_t *sm;  

  int sector, head, cylinder, total_sector;
  long temp;

  if (mem == MPIO_INTERNAL_MEM) sm = &m->internal;
  if (mem == MPIO_EXTERNAL_MEM) sm = &m->external;

  /* TODO: check a few things more, just to be sure */

  /* read CIS (just in case it might me usefull) */
  /* fixed @ offset 0x20 */
  if (mpio_io_sector_read(m, mem, 0x20, sm->size, 0, sm->cis)) {
    debug("error reading CIS\n");    
    return 1;
  }

  /* read MBR */
  /* fixed @ offset 0x40 */
  if (mpio_io_sector_read(m, mem, 0x40, sm->size, 0, sm->mbr)) {
    debug("error reading MBR\n");    
    return 1;
  }

  if ((sm->mbr[0x1fe] != 0x55) || (sm->mbr[0x1ff] != 0xaa)) {
    debug("This is not the MBR!\n");
    return 1;
  }
  
  /* always use the first partition */
  /* we probably don't need to support others */
  pe = sm->mbr + 0x1be;
  
  head = (int)(*(pe+0x01) & 0xff);
  sector = (int)(*(pe+0x02) & 0x3f);
  cylinder = (int)((*(pe+0x02) >> 6) * 0x100 + *(pe + 0x03));
  
  sm->pbr_offset=(cylinder * sm->geo.NumHead + head ) *
    sm->geo.NumSector + sector - 1 + OFFSET_MBR; 

  /* read PBR */
  if (mpio_io_sector_read(m, mem, sm->pbr_offset, sm->size, 0, sm->pbr))
      return 1;

  if ((sm->pbr[0x1fe] != 0x55) || (sm->pbr[0x1ff] != 0xaa)) {
    debug("This is not the PBR!\n");
    return 1;
  }

  if (strncmp((sm->pbr+0x36),"FAT", 3) != 0) {
    debug("Did not find an FAT signature, *not* good!, aborting!\n");
    exit (1);
  }

  bpb = sm->pbr + 0x0b;
  
  total_sector = (*(sm->pbr+0x14) * 0x100 + *(sm->pbr + 0x13));
  if (!total_sector)
      total_sector = (*(sm->pbr+0x23) * 0x1000000 + 
		      *(sm->pbr+0x22) * 0x10000   +
		      *(sm->pbr+0x21) * 0x100     +
		      *(sm->pbr+0x20));

   /* 128 MB need 2 Bytes instead of 1.5 */
   if (sm->size != 128)
     temp = ((total_sector / 0x20 * 0x03 / 0x02 / 0x200) + 0x01);   
   else
     temp = ((total_sector / 0x20 * 0x02 / 0x200) + 0x01);   

  sm->max_cluster = (total_sector / BLOCK_SECTORS);
  debugn(2,"max_cluster: %d\n", sm->max_cluster);
  sm->fat_offset = sm->pbr_offset + 0x01;
  sm->fat_size = temp;
  sm->fat_nums = *(sm->pbr + 0x10);
  sm->dir_offset = sm->pbr_offset + 0x01 +  temp * 2;

  return 0;  
}

/* read "fat_size" sectors of fat into the provided buffer */
int
mpio_fat_read (mpio_t *m, mpio_mem_t mem)
{
  mpio_smartmedia_t *sm;
  BYTE recvbuff[SECTOR_SIZE];
  int i;

  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    if (mpio_io_spare_read(m, mem, 0, (sm->size / sm->chips), 0, sm->fat,
			   (sm->fat_size * SECTOR_SIZE)))
      return 1;
    return 0;
  }
  
  if (mem == MPIO_EXTERNAL_MEM) sm = &m->external;
  
  for (i = 0; i < sm->fat_size; i++) {
    if (mpio_io_sector_read(m, mem, (sm->fat_offset + i),
			    sm->size, 0, recvbuff))
      return 1;

    memcpy(sm->fat + (i * SECTOR_SIZE), recvbuff, SECTOR_SIZE);
  }

  return (0);
}

int
mpio_fat_entry_free(mpio_t *m, mpio_mem_t mem, int entry )
{
  int e;
  mpio_smartmedia_t *sm;
  
  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    e = entry * 0x10;

    if((sm->fat[e+0] == 0xff) &&
       (sm->fat[e+1] == 0xff) &&
       (sm->fat[e+2] == 0xff))
      return 1;
  }

  if (mem == MPIO_EXTERNAL_MEM) {    
    sm = &m->internal;
    if (mpio_fat_entry_read(m, mem, entry) == 0)
      return 1;
  }

  return 0;
}

int
mpio_fat_entry_read(mpio_t *m, mpio_mem_t mem, int entry )
{
  mpio_smartmedia_t *sm;  
  int e;  
  int v;
  
  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    e = entry;    
    e = e * 0x10 + 7;
    if((sm->fat[e+0] == 0xff) &&
       (sm->fat[e+1] == 0xff) &&
       (sm->fat[e+2] == 0xff) &&
       (sm->fat[e+3] == 0xff))
      return 0xffffffff;
       
    v = (sm->fat[e+1] * 0x10000 +
	 sm->fat[e+2] * 0x100 +
	 sm->fat[e+3]) / 0x20 + sm->fat[e+0] * 0x1000000;    
  
    return v; 
  }
  
  if (mem == MPIO_EXTERNAL_MEM) sm = &m->external;

  if (sm->size == 128) {
    /* 2 Byte per entry */
    e = entry * 2;
    v = sm->fat[e + 1] * 0x100 + sm->fat[e];
  } else {
    /* 1.5 Byte per entry */
    /* Nibble order: x321 */
    e = (entry * 3 / 2);
/*     printf("mager: byte (%d/%d)\n", e, e+1); */
    if ((entry & 0x01) == 0) {
      /* LLxH */
      /* 21x3 */
      v = (sm->fat[e + 1] & 0x0f) * 0x100 + sm->fat[e];
    } else {
      /* 1x32 */
      v = (sm->fat[e + 1] * 0x10) + (sm->fat[e] >> 4);
    }    
  }

  return v;  
}

int 
mpio_fat_entry_write(mpio_t *m, mpio_mem_t mem, int entry, WORD value)
{
  mpio_smartmedia_t *sm;  
  int e;
  BYTE backup;

  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
  }
  
  if (mem == MPIO_EXTERNAL_MEM) {
    sm = &m->external;
  }
  if (sm->size == 128) {
    /* 2 Byte per entry */
    e = entry * 2;
    sm->fat[e]   = value & 0xff;
    sm->fat[e + 1] = (value >> 8 ) & 0xff;
    
  } else {
    /* 1.5 Byte per entry */
    e = (entry * 3 / 2);
    if ((entry & 0x01) == 0) {
      /* 21x3 */
      sm->fat[e]   = value & 0xff;
      backup       = sm->fat[e + 1] & 0xf0;
      sm->fat[e + 1] = backup | (( value / 0x100  ) & 0x0f);
    } else {
      /* 1x32 */
      sm->fat[e + 1] = (value / 0x10) & 0xff;
      backup       = sm->fat[e] & 0x0f;
      sm->fat[e]   = backup | ( (value * 0x10) & 0xf0 );
    }    
      
  }

  return 0;
}

int 
mpio_fat_internal_find_startsector(mpio_t *m, BYTE start)
{
  int i = 0;
  int found = 0;
  mpio_smartmedia_t *sm = &m->internal;

  while ((i < sm->max_cluster) && (!found)) {
    if ((sm->fat[i * 0x10]  == 0xaa) &&
	(sm->fat[i * 0x10 + 1] == start)) {
      found = i;
    }
    i++;      
  }

  return found;
}

int  
mpio_fat_free_clusters(mpio_t *m, mpio_mem_t mem)
{
  mpio_smartmedia_t *sm;  
  int i;
  int e = 0;
  int fsize;
  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    
    for (i = 0; i < sm->max_cluster; i++)
      if (mpio_fat_entry_free(m, mem, i)) e++;	
  }
  
  if (mem == MPIO_EXTERNAL_MEM) {
    sm = &m->external;
    fsize = sm->fat_size * SECTOR_SIZE;

    if (sm->size == 128) {
      fsize /= 2;
    } else {
      fsize *= 2;
      fsize /= 3;
    }
    for (i = 0; i < (sm->max_cluster - 1); i++)
      if (mpio_fat_entry_read(m, mem, i) == 0) e++;	
  }
    
  return (e * 16);
}

int  
mpio_fat_find_free(mpio_t *m, mpio_mem_t mem)
{
  mpio_smartmedia_t *sm;  
  int i;
  int fsize;
  int found = 0;

  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    
    for (i = 2; ((i < sm->max_cluster) && (!found)); i++)
      if (mpio_fat_entry_free(m, mem, i)) found = i;	
  }
  
  if (mem == MPIO_EXTERNAL_MEM) {
    sm = &m->external;
    fsize = sm->fat_size * SECTOR_SIZE;

    if (sm->size == 128) {
      fsize /= 2;
    } else {
      fsize *= 2;
      fsize /= 3;
    }
    for (i = 2; ((i < (sm->max_cluster-1)) && (!found)); i++)
      if (mpio_fat_entry_read(m, mem, i)==0)	found = i;	
  }

  return found;
}

int
mpio_fat_clear(mpio_t *m, mpio_mem_t mem)
{
  mpio_smartmedia_t *sm;
  
  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    debug("clearing of the internal FAT not yet supported , sorry\n");
    return 0;
  }
  
  if (mem == MPIO_EXTERNAL_MEM) {
    sm = &m->external;
    memset(sm->fat, 0x00, (sm->fat_size * SECTOR_SIZE));
    sm->fat[0] = 0xf8;
    sm->fat[1] = 0xff;
    sm->fat[2] = 0xff;
    /* for FAT 16 */
    if (sm->size == 128)      
      sm->fat[3] = 0xff;
  }
  
  return 0;
}

/* 
 * This function acutally writes both,
 * the FAT _and_ the root directory
 *
 */

int 
mpio_fat_write(mpio_t *m, mpio_mem_t mem)
{
  mpio_smartmedia_t *sm;
  BYTE dummy[BLOCK_SIZE];
  WORD i;
  
  if (mem == MPIO_INTERNAL_MEM) {    
    sm = &m->internal;
    debug("writing of the internal FAT is not yet supported, sorry\n");
    return 0;
  }
  
  if (mem == MPIO_EXTERNAL_MEM) sm=&m->external;

  memset(dummy, 0xff, BLOCK_SIZE);
  
  for (i = 0x40; i < (sm->dir_offset + DIR_NUM) ; i++) {
    if (((i / 0x20) * 0x20) == i) {
/*       debug("formatting: %2x\n", i); */
      mpio_io_block_delete(m, mem, i, sm->size);
    }
    
    if (i == 0x40)
      mpio_io_sector_write(m, mem, 0x40, sm->size, 0, sm->mbr);
    if ((i > 0x40) && (i < sm->pbr_offset))
      mpio_io_sector_write(m, mem, i, sm->size, 0, dummy);
      
    if (i == sm->pbr_offset)
      mpio_io_sector_write(m, mem, sm->pbr_offset, sm->size, 0, sm->pbr);
    
    if ((i >= sm->fat_offset) && (i < (sm->fat_offset + (2 * sm->fat_size)))) 
      mpio_io_sector_write(m, mem, i, sm->size, 0, 
			   (sm->fat + SECTOR_SIZE *
			    ((i - sm->fat_offset) % sm->fat_size)));
    
    if (i>=sm->dir_offset)
      mpio_io_sector_write(m, mem, i, sm->size, 0, 
			   (sm->dir + (i - sm->dir_offset) * SECTOR_SIZE));
  }
    
  return 0;
}