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