drivers/mtd/parsers/parser_trx.c

   1 /*
   2  * Parser for TRX format partitions
   3  *
   4  * Copyright (C) 2012 - 2017 Rafał Miłecki <rafal@milecki.pl>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/mtd/mtd.h>
  15 #include <linux/mtd/partitions.h>
  16
  17 #define TRX_PARSER_MAX_PARTS            4
  18
  19 /* Magics */
  20 #define TRX_MAGIC                       0x30524448
  21 #define UBI_EC_MAGIC                    0x23494255      /* UBI# */
  22
  23 struct trx_header {
  24         uint32_t magic;
  25         uint32_t length;
  26         uint32_t crc32;
  27         uint16_t flags;
  28         uint16_t version;
  29         uint32_t offset[3];
  30 } __packed;
  31
  32 static const char *parser_trx_data_part_name(struct mtd_info *master,
  33                                              size_t offset)
  34 {
  35         uint32_t buf;
  36         size_t bytes_read;
  37         int err;
  38
  39         err  = mtd_read(master, offset, sizeof(buf), &bytes_read,
  40                         (uint8_t *)&buf);
  41         if (err && !mtd_is_bitflip(err)) {
  42                 pr_err("mtd_read error while parsing (offset: 0x%zX): %d\n",
  43                         offset, err);
  44                 goto out_default;
  45         }
  46
  47         if (buf == UBI_EC_MAGIC)
  48                 return "ubi";
  49
  50 out_default:
  51         return "rootfs";
  52 }
  53
  54 static int parser_trx_parse(struct mtd_info *mtd,
  55                             const struct mtd_partition **pparts,
  56                             struct mtd_part_parser_data *data)
  57 {
  58         struct mtd_partition *parts;
  59         struct mtd_partition *part;
  60         struct trx_header trx;
  61         size_t bytes_read;
  62         uint8_t curr_part = 0, i = 0;
  63         int err;
  64
  65         parts = kzalloc(sizeof(struct mtd_partition) * TRX_PARSER_MAX_PARTS,
  66                         GFP_KERNEL);
  67         if (!parts)
  68                 return -ENOMEM;
  69
  70         err = mtd_read(mtd, 0, sizeof(trx), &bytes_read, (uint8_t *)&trx);
  71         if (err) {
  72                 pr_err("MTD reading error: %d\n", err);
  73                 kfree(parts);
  74                 return err;
  75         }
  76
  77         if (trx.magic != TRX_MAGIC) {
  78                 kfree(parts);
  79                 return -ENOENT;
  80         }
  81
  82         /* We have LZMA loader if there is address in offset[2] */
  83         if (trx.offset[2]) {
  84                 part = &parts[curr_part++];
  85                 part->name = "loader";
  86                 part->offset = trx.offset[i];
  87                 i++;
  88         }
  89
  90         if (trx.offset[i]) {
  91                 part = &parts[curr_part++];
  92                 part->name = "linux";
  93                 part->offset = trx.offset[i];
  94                 i++;
  95         }
  96
  97         if (trx.offset[i]) {
  98                 part = &parts[curr_part++];
  99                 part->name = parser_trx_data_part_name(mtd, trx.offset[i]);
 100                 part->offset = trx.offset[i];
 101                 i++;
 102         }
 103
 104         /*
 105          * Assume that every partition ends at the beginning of the one it is
 106          * followed by.
 107          */
 108         for (i = 0; i < curr_part; i++) {
 109                 u64 next_part_offset = (i < curr_part - 1) ?
 110                                        parts[i + 1].offset : mtd->size;
 111
 112                 parts[i].size = next_part_offset - parts[i].offset;
 113         }
 114
 115         *pparts = parts;
 116         return i;
 117 };
 118
 119 static struct mtd_part_parser mtd_parser_trx = {
 120         .parse_fn = parser_trx_parse,
 121         .name = "trx",
 122 };
 123 module_mtd_part_parser(mtd_parser_trx);
 124
 125 MODULE_LICENSE("GPL v2");
 126 MODULE_DESCRIPTION("Parser for TRX format partitions");