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
  26 struct wrgg03_header {
  27         char            signature[32];
  28         uint32_t        magic1;
  29         uint32_t        magic2;
  30         char            version[16];
  31         char            model[16];
  32         uint32_t        flag[2];
  33         uint32_t        reserve[2];
  34         char            buildno[16];
  35         uint32_t        size;
  36         uint32_t        offset;
  37         char            devname[32];
  38         char            digest[16];
  39 } __attribute__ ((packed));
  40
  41
  42 static int mtdsplit_parse_wrgg(struct mtd_info *master,
  43                                 struct mtd_partition **pparts,
  44                                 struct mtd_part_parser_data *data)
  45 {
  46         struct wrgg03_header hdr;
  47         size_t hdr_len, retlen, kernel_ent_size;
  48         size_t rootfs_offset;
  49         struct mtd_partition *parts;
  50         enum mtdsplit_part_type type;
  51         int err;
  52
  53         hdr_len = sizeof(hdr);
  54         err = mtd_read(master, 0, hdr_len, &retlen, (void *) &hdr);
  55         if (err)
  56                 return err;
  57
  58         if (retlen != hdr_len)
  59                 return -EIO;
  60
  61         /* sanity checks */
  62         if (le32_to_cpu(hdr.magic1) != WRGG03_MAGIC)
  63                 return -EINVAL;
  64
  65         kernel_ent_size = hdr_len + be32_to_cpu(hdr.size);
  66
  67         if (kernel_ent_size > master->size)
  68                 return -EINVAL;
  69
  70         /*
  71          * The size in the header covers the rootfs as well.
  72          * Start the search from an arbitrary offset.
  73          */
  74         err = mtd_find_rootfs_from(master, WRGG_MIN_ROOTFS_OFFS,
  75                                    master->size, &rootfs_offset, &type);
  76         if (err)
  77                 return err;
  78
  79         parts = kzalloc(WRGG_NR_PARTS * sizeof(*parts), GFP_KERNEL);
  80         if (!parts)
  81                 return -ENOMEM;
  82
  83         parts[0].name = KERNEL_PART_NAME;
  84         parts[0].offset = 0;
  85         parts[0].size = rootfs_offset;
  86
  87         parts[1].name = ROOTFS_PART_NAME;
  88         parts[1].offset = rootfs_offset;
  89         parts[1].size = master->size - rootfs_offset;
  90
  91         *pparts = parts;
  92         return WRGG_NR_PARTS;
  93 }
  94
  95 static struct mtd_part_parser mtdsplit_wrgg_parser = {
  96         .owner = THIS_MODULE,
  97         .name = "wrgg-fw",
  98         .parse_fn = mtdsplit_parse_wrgg,
  99         .type = MTD_PARSER_TYPE_FIRMWARE,
 100 };
 101
 102 static int __init mtdsplit_wrgg_init(void)
 103 {
 104         register_mtd_parser(&mtdsplit_wrgg_parser);
 105
 106         return 0;
 107 }
 108
 109 subsys_initcall(mtdsplit_wrgg_init);