target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_wrgg.c

   1 /*
   2  *  Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
   3  *  Copyright (C) 2014 Felix Fietkau <nbd@nbd.name>
   4  *  Copyright (C) 2016 Stijn Tintel <stijn@linux-ipv6.be>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify it
   7  *  under the terms of the GNU General Public License version 2 as published
   8  *  by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/mtd/partitions.h>
  18 #include <linux/byteorder/generic.h>
  19 #include <linux/of.h>
  20
  21 #include "mtdsplit.h"
  22
  23 #define WRGG_NR_PARTS           2
  24 #define WRGG_MIN_ROOTFS_OFFS    0x80000 /* 512KiB */
  25 #define WRGG03_MAGIC            0x20080321
  26 #define WRG_MAGIC               0x20040220
  27
  28 struct wrgg03_header {
  29         char            signature[32];
  30         uint32_t        magic1;
  31         uint32_t        magic2;
  32         char            version[16];
  33         char            model[16];
  34         uint32_t        flag[2];
  35         uint32_t        reserve[2];
  36         char            buildno[16];
  37         uint32_t        size;
  38         uint32_t        offset;
  39         char            devname[32];
  40         char            digest[16];
  41 } __attribute__ ((packed));
  42
  43 struct wrg_header {
  44         char            signature[32];
  45         uint32_t        magic1;
  46         uint32_t        magic2;
  47         uint32_t        size;
  48         uint32_t        offset;
  49         char            devname[32];
  50         char            digest[16];
  51 } __attribute__ ((packed));
  52
  53
  54 static int mtdsplit_parse_wrgg(struct mtd_info *master,
  55                                const struct mtd_partition **pparts,
  56                                struct mtd_part_parser_data *data)
  57 {
  58         struct wrgg03_header hdr;
  59         size_t hdr_len, retlen, kernel_ent_size;
  60         size_t rootfs_offset;
  61         struct mtd_partition *parts;
  62         enum mtdsplit_part_type type;
  63         int err;
  64
  65         hdr_len = sizeof(hdr);
  66         err = mtd_read(master, 0, hdr_len, &retlen, (void *) &hdr);
  67         if (err)
  68                 return err;
  69
  70         if (retlen != hdr_len)
  71                 return -EIO;
  72
  73         /* sanity checks */
  74         if (le32_to_cpu(hdr.magic1) == WRGG03_MAGIC) {
  75                 kernel_ent_size = hdr_len + be32_to_cpu(hdr.size);
  76                 /*
  77                  * If this becomes silly big it's probably because the
  78                  * WRGG image is little-endian.
  79                  */
  80                 if (kernel_ent_size > master->size)
  81                         kernel_ent_size = hdr_len + le32_to_cpu(hdr.size);
  82
  83                 /* Now what ?! It's neither */
  84                 if (kernel_ent_size > master->size)
  85                         return -EINVAL;
  86         } else if (le32_to_cpu(hdr.magic1) == WRG_MAGIC) {
  87                 kernel_ent_size = sizeof(struct wrg_header) + le32_to_cpu(
  88                                   ((struct wrg_header*)&hdr)->size);
  89         } else {
  90                 return -EINVAL;
  91         }
  92
  93         if (kernel_ent_size > master->size)
  94                 return -EINVAL;
  95
  96         /*
  97          * The size in the header covers the rootfs as well.
  98          * Start the search from an arbitrary offset.
  99          */
 100         err = mtd_find_rootfs_from(master, WRGG_MIN_ROOTFS_OFFS,
 101                                    master->size, &rootfs_offset, &type);
 102         if (err)
 103                 return err;
 104
 105         parts = kzalloc(WRGG_NR_PARTS * sizeof(*parts), GFP_KERNEL);
 106         if (!parts)
 107                 return -ENOMEM;
 108
 109         parts[0].name = KERNEL_PART_NAME;
 110         parts[0].offset = 0;
 111         parts[0].size = rootfs_offset;
 112
 113         parts[1].name = ROOTFS_PART_NAME;
 114         parts[1].offset = rootfs_offset;
 115         parts[1].size = master->size - rootfs_offset;
 116
 117         *pparts = parts;
 118         return WRGG_NR_PARTS;
 119 }
 120
 121 static const struct of_device_id mtdsplit_wrgg_of_match_table[] = {
 122         { .compatible = "wrg" },
 123         {},
 124 };
 125 MODULE_DEVICE_TABLE(of, mtdsplit_wrgg_of_match_table);
 126
 127 static struct mtd_part_parser mtdsplit_wrgg_parser = {
 128         .owner = THIS_MODULE,
 129         .name = "wrgg-fw",
 130         .of_match_table = mtdsplit_wrgg_of_match_table,
 131         .parse_fn = mtdsplit_parse_wrgg,
 132         .type = MTD_PARSER_TYPE_FIRMWARE,
 133 };
 134
 135 static int __init mtdsplit_wrgg_init(void)
 136 {
 137         register_mtd_parser(&mtdsplit_wrgg_parser);
 138
 139         return 0;
 140 }
 141
 142 subsys_initcall(mtdsplit_wrgg_init);