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