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/magic.h>
  30 #include <linux/module.h>
  31
  32 #define AR7_PARTS       4
  33 #define ROOT_OFFSET     0xe0000
  34
  35 #define LOADER_MAGIC1   le32_to_cpu(0xfeedfa42)
  36 #define LOADER_MAGIC2   le32_to_cpu(0xfeed1281)
  37
  38 #ifndef SQUASHFS_MAGIC
  39 #define SQUASHFS_MAGIC  0x73717368
  40 #endif
  41
  42 struct ar7_bin_rec {
  43         unsigned int checksum;
  44         unsigned int length;
  45         unsigned int address;
  46 };
  47
  48 static int create_mtd_partitions(struct mtd_info *master,
  49                                  struct mtd_partition **pparts,
  50                                  struct mtd_part_parser_data *data)
  51 {
  52         struct ar7_bin_rec header;
  53         unsigned int offset;
  54         size_t len;
  55         unsigned int pre_size = master->erasesize, post_size = 0;
  56         unsigned int root_offset = ROOT_OFFSET;
  57
  58         int retries = 10;
  59         struct mtd_partition *ar7_parts;
  60
  61         ar7_parts = kzalloc(sizeof(*ar7_parts) * AR7_PARTS, GFP_KERNEL);
  62         if (!ar7_parts)
  63                 return -ENOMEM;
  64         ar7_parts[0].name = "loader";
  65         ar7_parts[0].offset = 0;
  66         ar7_parts[0].size = master->erasesize;
  67         ar7_parts[0].mask_flags = MTD_WRITEABLE;
  68
  69         ar7_parts[1].name = "config";
  70         ar7_parts[1].offset = 0;
  71         ar7_parts[1].size = master->erasesize;
  72         ar7_parts[1].mask_flags = 0;
  73
  74         do { /* Try 10 blocks starting from master->erasesize */
  75                 offset = pre_size;
  76                 mtd_read(master, offset, sizeof(header), &len,
  77                          (uint8_t *)&header);
  78                 if (!strncmp((char *)&header, "TIENV0.8", 8))
  79                         ar7_parts[1].offset = pre_size;
  80                 if (header.checksum == LOADER_MAGIC1)
  81                         break;
  82                 if (header.checksum == LOADER_MAGIC2)
  83                         break;
  84                 pre_size += master->erasesize;
  85         } while (retries--);
  86
  87         pre_size = offset;
  88
  89         if (!ar7_parts[1].offset) {
  90                 ar7_parts[1].offset = master->size - master->erasesize;
  91                 post_size = master->erasesize;
  92         }
  93
  94         switch (header.checksum) {
  95         case LOADER_MAGIC1:
  96                 while (header.length) {
  97                         offset += sizeof(header) + header.length;
  98                         mtd_read(master, offset, sizeof(header), &len,
  99                                  (uint8_t *)&header);
 100                 }
 101                 root_offset = offset + sizeof(header) + 4;
 102                 break;
 103         case LOADER_MAGIC2:
 104                 while (header.length) {
 105                         offset += sizeof(header) + header.length;
 106                         mtd_read(master, offset, sizeof(header), &len,
 107                                  (uint8_t *)&header);
 108                 }
 109                 root_offset = offset + sizeof(header) + 4 + 0xff;
 110                 root_offset &= ~(uint32_t)0xff;
 111                 break;
 112         default:
 113                 printk(KERN_WARNING "Unknown magic: %08x\n", header.checksum);
 114                 break;
 115         }
 116
 117         mtd_read(master, root_offset, sizeof(header), &len, (u8 *)&header);
 118         if (header.checksum != SQUASHFS_MAGIC) {
 119                 root_offset += master->erasesize - 1;
 120                 root_offset &= ~(master->erasesize - 1);
 121         }
 122
 123         ar7_parts[2].name = "linux";
 124         ar7_parts[2].offset = pre_size;
 125         ar7_parts[2].size = master->size - pre_size - post_size;
 126         ar7_parts[2].mask_flags = 0;
 127
 128         ar7_parts[3].name = "rootfs";
 129         ar7_parts[3].offset = root_offset;
 130         ar7_parts[3].size = master->size - root_offset - post_size;
 131         ar7_parts[3].mask_flags = 0;
 132
 133         *pparts = ar7_parts;
 134         return AR7_PARTS;
 135 }
 136
 137 static struct mtd_part_parser ar7_parser = {
 138         .owner = THIS_MODULE,
 139         .parse_fn = create_mtd_partitions,
 140         .name = "ar7part",
 141 };
 142
 143 static int __init ar7_parser_init(void)
 144 {
 145         return register_mtd_parser(&ar7_parser);
 146 }
 147
 148 module_init(ar7_parser_init);
 149
 150 MODULE_LICENSE("GPL");
 151 MODULE_AUTHOR(  "Felix Fietkau <nbd@openwrt.org>, "
 152                 "Eugene Konev <ejka@openwrt.org>");
 153 MODULE_DESCRIPTION("MTD partitioning for TI AR7");