drivers/mtd/parsers/parser_trx.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Parser for TRX format partitions
   4  *
   5  * Copyright (C) 2012 - 2017 Rafał Miłecki <rafal@milecki.pl>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/mtd/mtd.h>
  11 #include <linux/mtd/partitions.h>
  12
  13 #define TRX_PARSER_MAX_PARTS            4
  14
  15 /* Magics */
  16 #define TRX_MAGIC                       0x30524448
  17 #define UBI_EC_MAGIC                    0x23494255      /* UBI# */
  18
  19 struct trx_header {
  20         uint32_t magic;
  21         uint32_t length;
  22         uint32_t crc32;
  23         uint16_t flags;
  24         uint16_t version;
  25         uint32_t offset[3];
  26 } __packed;
  27
  28 static const char *parser_trx_data_part_name(struct mtd_info *master,
  29                                              size_t offset)
  30 {
  31         uint32_t buf;
  32         size_t bytes_read;
  33         int err;
  34
  35         err  = mtd_read(master, offset, sizeof(buf), &bytes_read,
  36                         (uint8_t *)&buf);
  37         if (err && !mtd_is_bitflip(err)) {
  38                 pr_err("mtd_read error while parsing (offset: 0x%zX): %d\n",
  39                         offset, err);
  40                 goto out_default;
  41         }
  42
  43         if (buf == UBI_EC_MAGIC)
  44                 return "ubi";
  45
  46 out_default:
  47         return "rootfs";
  48 }
  49
  50 static int parser_trx_parse(struct mtd_info *mtd,
  51                             const struct mtd_partition **pparts,
  52                             struct mtd_part_parser_data *data)
  53 {
  54         struct mtd_partition *parts;
  55         struct mtd_partition *part;
  56         struct trx_header trx;
  57         size_t bytes_read;
  58         uint8_t curr_part = 0, i = 0;
  59         int err;
  60
  61         parts = kcalloc(TRX_PARSER_MAX_PARTS, sizeof(struct mtd_partition),
  62                         GFP_KERNEL);
  63         if (!parts)
  64                 return -ENOMEM;
  65
  66         err = mtd_read(mtd, 0, sizeof(trx), &bytes_read, (uint8_t *)&trx);
  67         if (err) {
  68                 pr_err("MTD reading error: %d\n", err);
  69                 kfree(parts);
  70                 return err;
  71         }
  72
  73         if (trx.magic != TRX_MAGIC) {
  74                 kfree(parts);
  75                 return -ENOENT;
  76         }
  77
  78         /* We have LZMA loader if there is address in offset[2] */
  79         if (trx.offset[2]) {
  80                 part = &parts[curr_part++];
  81                 part->name = "loader";
  82                 part->offset = trx.offset[i];
  83                 i++;
  84         }
  85
  86         if (trx.offset[i]) {
  87                 part = &parts[curr_part++];
  88                 part->name = "linux";
  89                 part->offset = trx.offset[i];
  90                 i++;
  91         }
  92
  93         if (trx.offset[i]) {
  94                 part = &parts[curr_part++];
  95                 part->name = parser_trx_data_part_name(mtd, trx.offset[i]);
  96                 part->offset = trx.offset[i];
  97                 i++;
  98         }
  99
 100         /*
 101          * Assume that every partition ends at the beginning of the one it is
 102          * followed by.
 103          */
 104         for (i = 0; i < curr_part; i++) {
 105                 u64 next_part_offset = (i < curr_part - 1) ?
 106                                        parts[i + 1].offset : mtd->size;
 107
 108                 parts[i].size = next_part_offset - parts[i].offset;
 109         }
 110
 111         *pparts = parts;
 112         return i;
 113 };
 114
 115 static const struct of_device_id mtd_parser_trx_of_match_table[] = {
 116         { .compatible = "brcm,trx" },
 117         {},
 118 };
 119 MODULE_DEVICE_TABLE(of, mtd_parser_trx_of_match_table);
 120
 121 static struct mtd_part_parser mtd_parser_trx = {
 122         .parse_fn = parser_trx_parse,
 123         .name = "trx",
 124         .of_match_table = mtd_parser_trx_of_match_table,
 125 };
 126 module_mtd_part_parser(mtd_parser_trx);
 127
 128 MODULE_LICENSE("GPL v2");
 129 MODULE_DESCRIPTION("Parser for TRX format partitions");