linux/drivers/mtd/ar7part.c
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   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
  42struct ar7_bin_rec {
  43        unsigned int checksum;
  44        unsigned int length;
  45        unsigned int address;
  46};
  47
  48static 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
 137static struct mtd_part_parser ar7_parser = {
 138        .owner = THIS_MODULE,
 139        .parse_fn = create_mtd_partitions,
 140        .name = "ar7part",
 141};
 142
 143static int __init ar7_parser_init(void)
 144{
 145        return register_mtd_parser(&ar7_parser);
 146}
 147
 148module_init(ar7_parser_init);
 149
 150MODULE_LICENSE("GPL");
 151MODULE_AUTHOR(  "Felix Fietkau <nbd@openwrt.org>, "
 152                "Eugene Konev <ejka@openwrt.org>");
 153MODULE_DESCRIPTION("MTD partitioning for TI AR7");
 154
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