disk.c

编译后直接运行的ＭＰ３播放器全部Ｃ语言源代码 一个包含FAT文件系统、系统引导 Boot、FLASH Driver等内容的

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id: disk.c,v 1.3 2002/10/10 12:01:57 zagor Exp $
 *
 * Copyright (C) 2002 by Bj鰎n Stenberg
 *
 * 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 <stdio.h>
#include "ata.h"
#include "debug.h"
#include "disk.h"

/* Partition table entry layout:
   -----------------------
   0: 0x80 - active
   1: starting head
   2: starting sector
   3: starting cylinder
   4: partition type
   5: end head
   6: end sector
   7: end cylinder
   8-11: starting sector (LBA)
   12-15: nr of sectors in partition
*/

#define BYTES2INT32(array,pos) \
          (array[pos] | (array[pos+1] << 8 ) | \
          (array[pos+2] << 16 ) | (array[pos+3] << 24 ))

static struct partinfo part[8];

struct partinfo* disk_init(void)
{
    int i;
    unsigned char sector[512];

    ata_read_sectors(0,1,&sector);

    /* check that the boot sector is initialized */
    if ( (sector[510] != 0x55) ||
         (sector[511] != 0xaa)) {
        DEBUGF("Bad boot sector signature\n");
        return NULL;
    }

    /* parse partitions */
    for ( i=0; i<4; i++ ) {
        unsigned char* ptr = sector + 0x1be + 16*i;
        part[i].type  = ptr[4];
        part[i].start = BYTES2INT32(ptr, 8);
        part[i].size  = BYTES2INT32(ptr, 12);

        DEBUGF("Part%d: Type %02x, start: %08x size: %08x\n",
               i,part[i].type,part[i].start,part[i].size);

        /* extended? */
        if ( part[i].type == 5 ) {
            /* not handled yet */
        }
    }

    return part;
}

struct partinfo* disk_partinfo(int partition)
{
    return &part[partition];
}