fs/ext2/dev.c

   1 /*
   2  * (C) Copyright 2004
   3  *  esd gmbh <www.esd-electronics.com>
   4  *  Reinhard Arlt <reinhard.arlt@esd-electronics.com>
   5  *
   6  *  based on code of fs/reiserfs/dev.c by
   7  *
   8  *  (C) Copyright 2003 - 2004
   9  *  Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License as published by
  13  *  the Free Software Foundation; either version 2 of the License, or
  14  *  (at your option) any later version.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to the Free Software
  23  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25
  26
  27 #include <common.h>
  28 #include <config.h>
  29 #include <ext2fs.h>
  30
  31 static block_dev_desc_t *ext2fs_block_dev_desc;
  32 static disk_partition_t part_info;
  33
  34 int ext2fs_set_blk_dev(block_dev_desc_t *rbdd, int part)
  35 {
  36         ext2fs_block_dev_desc = rbdd;
  37
  38         if (part == 0) {
  39                 /* disk doesn't use partition table */
  40                 part_info.start = 0;
  41                 part_info.size = rbdd->lba;
  42                 part_info.blksz = rbdd->blksz;
  43         } else {
  44                 if (get_partition_info
  45                     (ext2fs_block_dev_desc, part, &part_info)) {
  46                         return 0;
  47                 }
  48         }
  49         return part_info.size;
  50 }
  51
  52
  53 int ext2fs_devread(int sector, int byte_offset, int byte_len, char *buf)
  54 {
  55         char sec_buf[SECTOR_SIZE];
  56         unsigned sectors;
  57
  58         /*
  59          *  Check partition boundaries
  60          */
  61         if ((sector < 0) ||
  62             ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >=
  63                 part_info.size)) {
  64                 /* errnum = ERR_OUTSIDE_PART; */
  65                 printf(" ** %s read outside partition sector %d\n",
  66                        __func__,
  67                        sector);
  68                 return 0;
  69         }
  70
  71         /*
  72          *  Get the read to the beginning of a partition.
  73          */
  74         sector += byte_offset >> SECTOR_BITS;
  75         byte_offset &= SECTOR_SIZE - 1;
  76
  77         debug(" <%d, %d, %d>\n", sector, byte_offset, byte_len);
  78
  79         if (ext2fs_block_dev_desc == NULL) {
  80                 printf(" ** %s Invalid Block Device Descriptor (NULL)\n",
  81                        __func__);
  82                 return 0;
  83         }
  84
  85         if (byte_offset != 0) {
  86                 /* read first part which isn't aligned with start of sector */
  87                 if (ext2fs_block_dev_desc->
  88                     block_read(ext2fs_block_dev_desc->dev,
  89                                part_info.start + sector, 1,
  90                                (unsigned long *) sec_buf) != 1) {
  91                         printf(" ** %s read error **\n", __func__);
  92                         return 0;
  93                 }
  94                 memcpy(buf, sec_buf + byte_offset,
  95                        min(SECTOR_SIZE - byte_offset, byte_len));
  96                 buf += min(SECTOR_SIZE - byte_offset, byte_len);
  97                 byte_len -= min(SECTOR_SIZE - byte_offset, byte_len);
  98                 sector++;
  99         }
 100
 101         /*  read sector aligned part */
 102         sectors = byte_len / SECTOR_SIZE;
 103
 104         if (sectors > 0) {
 105                 if (ext2fs_block_dev_desc->block_read(
 106                         ext2fs_block_dev_desc->dev,
 107                         part_info.start + sector,
 108                         sectors,
 109                         (unsigned long *) buf) != sectors) {
 110                         printf(" ** %s read error - block\n", __func__);
 111                         return 0;
 112                 }
 113
 114                 buf += sectors * SECTOR_SIZE;
 115                 byte_len -= sectors * SECTOR_SIZE;
 116                 sector += sectors;
 117         }
 118
 119         if (byte_len != 0) {
 120                 /* read rest of data which are not in whole sector */
 121                 if (ext2fs_block_dev_desc->
 122                     block_read(ext2fs_block_dev_desc->dev,
 123                                part_info.start + sector, 1,
 124                                (unsigned long *) sec_buf) != 1) {
 125                         printf(" ** %s read error - last part\n", __func__);
 126                         return 0;
 127                 }
 128                 memcpy(buf, sec_buf, byte_len);
 129         }
 130         return 1;
 131 }