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
19struct 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
28static 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
46out_default:
47	return "rootfs";
48}
49
50static 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
115static const struct of_device_id mtd_parser_trx_of_match_table[] = {
116	{ .compatible = "brcm,trx" },
117	{},
118};
119MODULE_DEVICE_TABLE(of, mtd_parser_trx_of_match_table);
120
121static 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};
126module_mtd_part_parser(mtd_parser_trx);
127
128MODULE_LICENSE("GPL v2");
129MODULE_DESCRIPTION("Parser for TRX format partitions");
130