target/linux/ar71xx/files/drivers/mtd/tplinkpart.c

   1 /*
   2  * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 as published
   6  * by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/magic.h>
  15
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/mtd/partitions.h>
  18
  19 #define TPLINK_NUM_PARTS        5
  20 #define TPLINK_HEADER_V1        0x01000000
  21 #define MD5SUM_LEN              16
  22
  23 #define TPLINK_ART_LEN          0x10000
  24 #define TPLINK_KERNEL_OFFS      0x20000
  25
  26 struct tplink_fw_header {
  27         uint32_t        version;        /* header version */
  28         char            vendor_name[24];
  29         char            fw_version[36];
  30         uint32_t        hw_id;          /* hardware id */
  31         uint32_t        hw_rev;         /* hardware revision */
  32         uint32_t        unk1;
  33         uint8_t         md5sum1[MD5SUM_LEN];
  34         uint32_t        unk2;
  35         uint8_t         md5sum2[MD5SUM_LEN];
  36         uint32_t        unk3;
  37         uint32_t        kernel_la;      /* kernel load address */
  38         uint32_t        kernel_ep;      /* kernel entry point */
  39         uint32_t        fw_length;      /* total length of the firmware */
  40         uint32_t        kernel_ofs;     /* kernel data offset */
  41         uint32_t        kernel_len;     /* kernel data length */
  42         uint32_t        rootfs_ofs;     /* rootfs data offset */
  43         uint32_t        rootfs_len;     /* rootfs data length */
  44         uint32_t        boot_ofs;       /* bootloader data offset */
  45         uint32_t        boot_len;       /* bootloader data length */
  46         uint8_t         pad[360];
  47 } __attribute__ ((packed));
  48
  49 static struct tplink_fw_header *
  50 tplink_read_header(struct mtd_info *mtd, size_t offset)
  51 {
  52         struct tplink_fw_header *header;
  53         size_t header_len;
  54         size_t retlen;
  55         int ret;
  56         u32 t;
  57
  58         header = vmalloc(sizeof(*header));
  59         if (!header)
  60                 goto err;
  61
  62         header_len = sizeof(struct tplink_fw_header);
  63         ret = mtd->read(mtd, offset, header_len, &retlen,
  64                         (unsigned char *) header);
  65         if (ret)
  66                 goto err_free_header;
  67
  68         if (retlen != header_len)
  69                 goto err_free_header;
  70
  71         /* sanity checks */
  72         t = be32_to_cpu(header->version);
  73         if (t != TPLINK_HEADER_V1)
  74                 goto err_free_header;
  75
  76         t = be32_to_cpu(header->kernel_ofs);
  77         if (t != header_len)
  78                 goto err_free_header;
  79
  80         return header;
  81
  82 err_free_header:
  83         vfree(header);
  84 err:
  85         return NULL;
  86 }
  87
  88 static int tplink_check_rootfs_magic(struct mtd_info *mtd, size_t offset)
  89 {
  90         u32 magic;
  91         size_t retlen;
  92         int ret;
  93
  94         ret = mtd->read(mtd, offset, sizeof(magic), &retlen,
  95                         (unsigned char *) &magic);
  96         if (ret)
  97                 return ret;
  98
  99         if (retlen != sizeof(magic))
 100                 return -EIO;
 101
 102         if (le32_to_cpu(magic) != SQUASHFS_MAGIC &&
 103             magic != 0x19852003)
 104                 return -EINVAL;
 105
 106         return 0;
 107 }
 108
 109 static int tplink_parse_partitions(struct mtd_info *master,
 110                                    struct mtd_partition **pparts,
 111                                    unsigned long origin)
 112 {
 113         struct mtd_partition *parts;
 114         struct tplink_fw_header *header;
 115         int nr_parts;
 116         size_t offset;
 117         size_t art_offset;
 118         size_t rootfs_offset;
 119         size_t squashfs_offset;
 120         int ret;
 121
 122         nr_parts = TPLINK_NUM_PARTS;
 123         parts = kzalloc(nr_parts * sizeof(struct mtd_partition), GFP_KERNEL);
 124         if (!parts) {
 125                 ret = -ENOMEM;
 126                 goto err;
 127         }
 128
 129         offset = TPLINK_KERNEL_OFFS;
 130
 131         header = tplink_read_header(master, offset);
 132         if (!header) {
 133                 pr_notice("%s: no TP-Link header found\n", master->name);
 134                 ret = -ENODEV;
 135                 goto err_free_parts;
 136         }
 137
 138         squashfs_offset = offset + sizeof(struct tplink_fw_header) +
 139                           be32_to_cpu(header->kernel_len);
 140
 141         ret = tplink_check_rootfs_magic(master, squashfs_offset);
 142         if (ret == 0)
 143                 rootfs_offset = squashfs_offset;
 144         else
 145                 rootfs_offset = offset + be32_to_cpu(header->rootfs_ofs);
 146
 147         art_offset = master->size - TPLINK_ART_LEN;
 148
 149         parts[0].name = "u-boot";
 150         parts[0].offset = 0;
 151         parts[0].size = offset;
 152         parts[0].mask_flags = MTD_WRITEABLE;
 153
 154         parts[1].name = "kernel";
 155         parts[1].offset = offset;
 156         parts[1].size = rootfs_offset - offset;
 157
 158         parts[2].name = "rootfs";
 159         parts[2].offset = rootfs_offset;
 160         parts[2].size = art_offset - rootfs_offset;
 161
 162         parts[3].name = "art";
 163         parts[3].offset = art_offset;
 164         parts[3].size = TPLINK_ART_LEN;
 165         parts[3].mask_flags = MTD_WRITEABLE;
 166
 167         parts[4].name = "firmware";
 168         parts[4].offset = offset;
 169         parts[4].size = art_offset - offset;
 170
 171         vfree(header);
 172
 173         *pparts = parts;
 174         return nr_parts;
 175
 176 err_free_parts:
 177         kfree(parts);
 178 err:
 179         *pparts = NULL;
 180         return ret;
 181 }
 182
 183 static struct mtd_part_parser tplink_parser = {
 184         .owner          = THIS_MODULE,
 185         .parse_fn       = tplink_parse_partitions,
 186         .name           = "tp-link",
 187 };
 188
 189 static int __init tplink_parser_init(void)
 190 {
 191         return register_mtd_parser(&tplink_parser);
 192 }
 193
 194 module_init(tplink_parser_init);
 195
 196 MODULE_LICENSE("GPL v2");
 197 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");