target/linux/ar7-2.6/files/drivers/mtd/ar7part.c

   1 /*
   2  * $Id$
   3  *
   4  * Copyright (C) 2007 OpenWrt.org
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * TI AR7 flash partition table.
  21  * Based on ar7 map by Felix Fietkau.
  22  *
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/slab.h>
  27
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/partitions.h>
  30 #include <linux/bootmem.h>
  31 #include <linux/squashfs_fs.h>
  32
  33 struct ar7_bin_rec {
  34         unsigned int checksum;
  35         unsigned int length;
  36         unsigned int address;
  37 };
  38
  39 static struct mtd_partition ar7_parts[5];
  40
  41 static int create_mtd_partitions(struct mtd_info *master,
  42                                  struct mtd_partition **pparts,
  43                                  unsigned long origin)
  44 {
  45         char sig[8];
  46         struct ar7_bin_rec header;
  47         unsigned int offset, new_offset, len;
  48         struct squashfs_super_block sb;
  49         unsigned int block_size = 0x10000, pre_size = 0x10000,
  50                 post_size = 0, root_offset = 0xe0000;
  51         unsigned int p = 3;
  52
  53         printk("Parsing AR7 partition map...\n");
  54
  55         ar7_parts[0].name = "loader";
  56         ar7_parts[0].offset = 0;
  57         ar7_parts[0].size = block_size;
  58         ar7_parts[0].mask_flags = MTD_WRITEABLE;
  59
  60         ar7_parts[1].name = "config";
  61         ar7_parts[1].size = block_size;
  62         ar7_parts[1].mask_flags = 0;
  63
  64         master->read(master, block_size, 8, &len, sig);
  65         if (strncmp(sig, "TIENV0.8", 8)) {
  66                 ar7_parts[1].offset = master->size - block_size;
  67                 post_size = block_size;
  68         } else {
  69                 ar7_parts[1].offset = block_size;
  70                 pre_size = block_size * 2;
  71         }
  72
  73         ar7_parts[2].name = "linux";
  74         ar7_parts[2].offset = pre_size;
  75         ar7_parts[2].size = master->size - block_size * 2;
  76         ar7_parts[2].mask_flags = 0;
  77
  78         offset = pre_size;
  79         master->read(master, offset, sizeof(header), &len, (u_char *)&header);
  80         if (header.checksum != 0xfeedfa42) {
  81                 printk("Unknown magic: %08x\n", header.checksum);
  82         } else {
  83                 while (header.length) {
  84                         offset += sizeof(header) + header.length;
  85                         master->read(master, offset, sizeof(header),
  86                                      &len, (u_char *)&header);
  87                 }
  88                 root_offset = offset + sizeof(header) + 4;
  89         }
  90
  91         ar7_parts[p].name = "rootfs";
  92         ar7_parts[p].offset = root_offset;
  93         ar7_parts[p].size = master->size - root_offset - post_size;
  94         ar7_parts[p++].mask_flags = 0;
  95
  96         master->read(master, root_offset, sizeof(sb), &len, (u_char *)&sb);
  97         if (sb.s_magic == SQUASHFS_MAGIC) {
  98                 printk("Squashfs detected (size %Ld)\n", sb.bytes_used);
  99                 new_offset = root_offset + sb.bytes_used;
 100
 101                 if ((new_offset % master->erasesize) > 0)
 102                         new_offset += master->erasesize -
 103                                 (new_offset % master->erasesize);
 104
 105                 ar7_parts[p].name = "rootfs_data";
 106                 ar7_parts[p].offset = new_offset;
 107                 ar7_parts[p].size = master->size - new_offset - post_size;
 108                 ar7_parts[p - 1].size -= ar7_parts[p].size;
 109                 ar7_parts[p - 1].mask_flags |= MTD_WRITEABLE;
 110                 ar7_parts[p++].mask_flags = 0;
 111         } else {
 112                 printk("Squashfs not found. Moving rootfs partition to next erase block\n");
 113                 if ((root_offset % master->erasesize) > 0)
 114                         root_offset += master->erasesize -
 115                                 (root_offset % master->erasesize);
 116
 117                 ar7_parts[p].offset = root_offset;
 118                 ar7_parts[p].size = master->size - root_offset - post_size;
 119         }
 120         *pparts = ar7_parts;
 121         return p;
 122 }
 123
 124 static struct mtd_part_parser ar7_parser = {
 125         .owner = THIS_MODULE,
 126         .parse_fn = create_mtd_partitions,
 127         .name = "ar7part",
 128 };
 129
 130 static int __init ar7_parser_init(void)
 131 {
 132         return register_mtd_parser(&ar7_parser);
 133 }
 134
 135 module_init(ar7_parser_init);
 136
 137 MODULE_LICENSE("GPL");
 138 MODULE_AUTHOR("Felix Fietkau, Eugene Konev");
 139 MODULE_DESCRIPTION("MTD partitioning for TI AR7");