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 #include <linux/root_dev.h>
  33
  34 struct ar7_bin_rec {
  35         unsigned int checksum;
  36         unsigned int length;
  37         unsigned int address;
  38 };
  39
  40 static struct mtd_partition ar7_parts[5];
  41
  42 static int create_mtd_partitions(struct mtd_info *master,
  43                                  struct mtd_partition **pparts,
  44                                  unsigned long origin)
  45 {
  46         char sig[8];
  47         struct ar7_bin_rec header;
  48         unsigned int offset, new_offset, len;
  49         struct squashfs_super_block sb;
  50         unsigned int block_size = 0x10000, pre_size = 0x10000,
  51                 post_size = 0, root_offset = 0xe0000;
  52         unsigned int p = 3;
  53
  54         printk("Parsing AR7 partition map...\n");
  55
  56         ar7_parts[0].name = "loader";
  57         ar7_parts[0].offset = 0;
  58         ar7_parts[0].size = block_size;
  59         ar7_parts[0].mask_flags = MTD_WRITEABLE;
  60
  61         ar7_parts[1].name = "config";
  62         ar7_parts[1].size = block_size;
  63         ar7_parts[1].mask_flags = 0;
  64
  65         master->read(master, block_size, 8, &len, sig);
  66         if (strncmp(sig, "TIENV0.8", 8)) {
  67                 ar7_parts[1].offset = master->size - block_size;
  68                 post_size = block_size;
  69         } else {
  70                 ar7_parts[1].offset = block_size;
  71                 pre_size = block_size * 2;
  72         }
  73
  74         ar7_parts[2].name = "linux";
  75         ar7_parts[2].offset = pre_size;
  76         ar7_parts[2].size = master->size - block_size * 2;
  77         ar7_parts[2].mask_flags = 0;
  78
  79         offset = pre_size;
  80         master->read(master, offset, sizeof(header), &len, (u_char *)&header);
  81         if (header.checksum != 0xfeedfa42) {
  82                 printk("Unknown magic: %08x\n", header.checksum);
  83         } else {
  84                 while (header.length) {
  85                         offset += sizeof(header) + header.length;
  86                         master->read(master, offset, sizeof(header),
  87                                      &len, (u_char *)&header);
  88                 }
  89                 root_offset = offset + sizeof(header) + 4;
  90         }
  91
  92         ar7_parts[p].name = "rootfs";
  93         ar7_parts[p].offset = root_offset;
  94         ar7_parts[p].size = master->size - root_offset - post_size;
  95         ar7_parts[p++].mask_flags = 0;
  96
  97         master->read(master, root_offset, sizeof(sb), &len, (u_char *)&sb);
  98         if (sb.s_magic == SQUASHFS_MAGIC) {
  99                 printk("Squashfs detected (size %Ld)\n", sb.bytes_used);
 100                 new_offset = root_offset + sb.bytes_used;
 101
 102                 if ((new_offset % master->erasesize) > 0)
 103                         new_offset += master->erasesize -
 104                                 (new_offset % master->erasesize);
 105
 106                 ar7_parts[p].name = "rootfs_data";
 107                 ar7_parts[p].offset = new_offset;
 108                 ar7_parts[p].size = master->size - new_offset - post_size;
 109                 ar7_parts[p - 1].size -= ar7_parts[p].size;
 110                 ar7_parts[p - 1].mask_flags |= MTD_WRITEABLE;
 111                 ar7_parts[p++].mask_flags = 0;
 112                 ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, p - 1);
 113         } else {
 114                 printk("Squashfs not found. Moving rootfs partition to next erase block\n");
 115                 if ((root_offset % master->erasesize) > 0)
 116                         root_offset += master->erasesize -
 117                                 (root_offset % master->erasesize);
 118
 119                 ar7_parts[p].offset = root_offset;
 120                 ar7_parts[p].size = master->size - root_offset - post_size;
 121                 ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, p);
 122         }
 123         *pparts = ar7_parts;
 124         return p;
 125 }
 126
 127 static struct mtd_part_parser ar7_parser = {
 128         .owner = THIS_MODULE,
 129         .parse_fn = create_mtd_partitions,
 130         .name = "ar7part",
 131 };
 132
 133 static int __init ar7_parser_init(void)
 134 {
 135         return register_mtd_parser(&ar7_parser);
 136 }
 137
 138 module_init(ar7_parser_init);
 139
 140 MODULE_LICENSE("GPL");
 141 MODULE_AUTHOR("Felix Fietkau, Eugene Konev");
 142 MODULE_DESCRIPTION("MTD partitioning for TI AR7");