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

   1 /*
   2  * Copyright (C) 2007 Eugene Konev <ejka@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  *
  18  * TI AR7 flash partition table.
  19  * Based on ar7 map by Felix Fietkau <nbd@openwrt.org>
  20  *
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/slab.h>
  25
  26 #include <linux/mtd/mtd.h>
  27 #include <linux/mtd/partitions.h>
  28 #include <linux/bootmem.h>
  29 #include <linux/squashfs_fs.h>
  30
  31 struct ar7_bin_rec {
  32         unsigned int checksum;
  33         unsigned int length;
  34         unsigned int address;
  35 };
  36
  37 static struct mtd_partition ar7_parts[5];
  38
  39 static int create_mtd_partitions(struct mtd_info *master,
  40                                  struct mtd_partition **pparts,
  41                                  unsigned long origin)
  42 {
  43         struct ar7_bin_rec header;
  44         unsigned int offset, len;
  45         unsigned int pre_size = master->erasesize, post_size = 0;
  46         unsigned int root_offset = 0xe0000;
  47
  48         int retries = 10;
  49
  50         printk(KERN_INFO "Parsing AR7 partition map...\n");
  51
  52         ar7_parts[0].name = "loader";
  53         ar7_parts[0].offset = 0;
  54         ar7_parts[0].size = master->erasesize;
  55         ar7_parts[0].mask_flags = MTD_WRITEABLE;
  56
  57         ar7_parts[1].name = "config";
  58         ar7_parts[1].offset = 0;
  59         ar7_parts[1].size = master->erasesize;
  60         ar7_parts[1].mask_flags = 0;
  61
  62         do { /* Try 10 blocks starting from master->erasesize */
  63                 offset = pre_size;
  64                 master->read(master, offset,
  65                         sizeof(header), &len, (u_char *)&header);
  66                 if (!strncmp((char *)&header, "TIENV0.8", 8))
  67                         ar7_parts[1].offset = pre_size;
  68                 if (header.checksum == 0xfeedfa42)
  69                         break;
  70                 if (header.checksum == 0xfeed1281)
  71                         break;
  72                 pre_size += master->erasesize;
  73         } while (retries--);
  74
  75         pre_size = offset;
  76
  77         if (!ar7_parts[1].offset) {
  78                 ar7_parts[1].offset = master->size - master->erasesize;
  79                 post_size = master->erasesize;
  80         }
  81
  82         switch (header.checksum) {
  83         case 0xfeedfa42:
  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                 break;
  91         case 0xfeed1281:
  92                 while (header.length) {
  93                         offset += sizeof(header) + header.length;
  94                         master->read(master, offset, sizeof(header),
  95                                      &len, (u_char *)&header);
  96                 }
  97                 root_offset = offset + sizeof(header) + 4 + 0xff;
  98                 root_offset &= ~(u32)0xff;
  99                 break;
 100         default:
 101                 printk(KERN_WARNING "Unknown magic: %08x\n", header.checksum);
 102                 break;
 103         }
 104
 105         master->read(master, root_offset,
 106                 sizeof(header), &len, (u_char *)&header);
 107         if (header.checksum != SQUASHFS_MAGIC) {
 108                 root_offset += master->erasesize - 1;
 109                 root_offset &= ~(master->erasesize - 1);
 110         }
 111
 112         ar7_parts[2].name = "linux";
 113         ar7_parts[2].offset = pre_size;
 114         ar7_parts[2].size = master->size - pre_size - post_size;
 115         ar7_parts[2].mask_flags = 0;
 116
 117         ar7_parts[3].name = "rootfs";
 118         ar7_parts[3].offset = root_offset;
 119         ar7_parts[3].size = master->size - root_offset - post_size;
 120         ar7_parts[3].mask_flags = 0;
 121
 122         *pparts = ar7_parts;
 123         return 4;
 124 }
 125
 126 static struct mtd_part_parser ar7_parser = {
 127         .owner = THIS_MODULE,
 128         .parse_fn = create_mtd_partitions,
 129         .name = "ar7part",
 130 };
 131
 132 static int __init ar7_parser_init(void)
 133 {
 134         return register_mtd_parser(&ar7_parser);
 135 }
 136
 137 module_init(ar7_parser_init);
 138
 139 MODULE_LICENSE("GPL");
 140 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>, Eugene Konev <ejka@openwrt.org>");
 141 MODULE_DESCRIPTION("MTD partitioning for TI AR7");