drivers/mtd/ar7part.c

   1 /*
   2  * Copyright © 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/module.h>
  30
  31 #include <uapi/linux/magic.h>
  32
  33 #define AR7_PARTS       4
  34 #define ROOT_OFFSET     0xe0000
  35
  36 #define LOADER_MAGIC1   le32_to_cpu(0xfeedfa42)
  37 #define LOADER_MAGIC2   le32_to_cpu(0xfeed1281)
  38
  39 struct ar7_bin_rec {
  40         unsigned int checksum;
  41         unsigned int length;
  42         unsigned int address;
  43 };
  44
  45 static int create_mtd_partitions(struct mtd_info *master,
  46                                  const struct mtd_partition **pparts,
  47                                  struct mtd_part_parser_data *data)
  48 {
  49         struct ar7_bin_rec header;
  50         unsigned int offset;
  51         size_t len;
  52         unsigned int pre_size = master->erasesize, post_size = 0;
  53         unsigned int root_offset = ROOT_OFFSET;
  54
  55         int retries = 10;
  56         struct mtd_partition *ar7_parts;
  57
  58         ar7_parts = kcalloc(AR7_PARTS, sizeof(*ar7_parts), GFP_KERNEL);
  59         if (!ar7_parts)
  60                 return -ENOMEM;
  61         ar7_parts[0].name = "loader";
  62         ar7_parts[0].offset = 0;
  63         ar7_parts[0].size = master->erasesize;
  64         ar7_parts[0].mask_flags = MTD_WRITEABLE;
  65
  66         ar7_parts[1].name = "config";
  67         ar7_parts[1].offset = 0;
  68         ar7_parts[1].size = master->erasesize;
  69         ar7_parts[1].mask_flags = 0;
  70
  71         do { /* Try 10 blocks starting from master->erasesize */
  72                 offset = pre_size;
  73                 mtd_read(master, offset, sizeof(header), &len,
  74                          (uint8_t *)&header);
  75                 if (!strncmp((char *)&header, "TIENV0.8", 8))
  76                         ar7_parts[1].offset = pre_size;
  77                 if (header.checksum == LOADER_MAGIC1)
  78                         break;
  79                 if (header.checksum == LOADER_MAGIC2)
  80                         break;
  81                 pre_size += master->erasesize;
  82         } while (retries--);
  83
  84         pre_size = offset;
  85
  86         if (!ar7_parts[1].offset) {
  87                 ar7_parts[1].offset = master->size - master->erasesize;
  88                 post_size = master->erasesize;
  89         }
  90
  91         switch (header.checksum) {
  92         case LOADER_MAGIC1:
  93                 while (header.length) {
  94                         offset += sizeof(header) + header.length;
  95                         mtd_read(master, offset, sizeof(header), &len,
  96                                  (uint8_t *)&header);
  97                 }
  98                 root_offset = offset + sizeof(header) + 4;
  99                 break;
 100         case LOADER_MAGIC2:
 101                 while (header.length) {
 102                         offset += sizeof(header) + header.length;
 103                         mtd_read(master, offset, sizeof(header), &len,
 104                                  (uint8_t *)&header);
 105                 }
 106                 root_offset = offset + sizeof(header) + 4 + 0xff;
 107                 root_offset &= ~(uint32_t)0xff;
 108                 break;
 109         default:
 110                 printk(KERN_WARNING "Unknown magic: %08x\n", header.checksum);
 111                 break;
 112         }
 113
 114         mtd_read(master, root_offset, sizeof(header), &len, (u8 *)&header);
 115         if (header.checksum != SQUASHFS_MAGIC) {
 116                 root_offset += master->erasesize - 1;
 117                 root_offset &= ~(master->erasesize - 1);
 118         }
 119
 120         ar7_parts[2].name = "linux";
 121         ar7_parts[2].offset = pre_size;
 122         ar7_parts[2].size = master->size - pre_size - post_size;
 123         ar7_parts[2].mask_flags = 0;
 124
 125         ar7_parts[3].name = "rootfs";
 126         ar7_parts[3].offset = root_offset;
 127         ar7_parts[3].size = master->size - root_offset - post_size;
 128         ar7_parts[3].mask_flags = 0;
 129
 130         *pparts = ar7_parts;
 131         return AR7_PARTS;
 132 }
 133
 134 static struct mtd_part_parser ar7_parser = {
 135         .parse_fn = create_mtd_partitions,
 136         .name = "ar7part",
 137 };
 138 module_mtd_part_parser(ar7_parser);
 139
 140 MODULE_LICENSE("GPL");
 141 MODULE_AUTHOR(  "Felix Fietkau <nbd@openwrt.org>, "
 142                 "Eugene Konev <ejka@openwrt.org>");
 143 MODULE_DESCRIPTION("MTD partitioning for TI AR7");