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
parser_trx_data_part_name(struct mtd_info * master,size_t offset)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
parser_trx_parse(struct mtd_info * mtd,const struct mtd_partition ** pparts,struct mtd_part_parser_data * data)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 device_node *np = mtd_get_of_node(mtd);
55 struct mtd_partition *parts;
56 struct mtd_partition *part;
57 struct trx_header trx;
58 size_t bytes_read;
59 uint8_t curr_part = 0, i = 0;
60 uint32_t trx_magic = TRX_MAGIC;
61 int err;
62
63 /* Get different magic from device tree if specified */
64 err = of_property_read_u32(np, "brcm,trx-magic", &trx_magic);
65 if (err != 0 && err != -EINVAL)
66 pr_err("failed to parse \"brcm,trx-magic\" DT attribute, using default: %d\n", err);
67
68 parts = kcalloc(TRX_PARSER_MAX_PARTS, sizeof(struct mtd_partition),
69 GFP_KERNEL);
70 if (!parts)
71 return -ENOMEM;
72
73 err = mtd_read(mtd, 0, sizeof(trx), &bytes_read, (uint8_t *)&trx);
74 if (err) {
75 pr_err("MTD reading error: %d\n", err);
76 kfree(parts);
77 return err;
78 }
79
80 if (trx.magic != trx_magic) {
81 kfree(parts);
82 return -ENOENT;
83 }
84
85 /* We have LZMA loader if there is address in offset[2] */
86 if (trx.offset[2]) {
87 part = &parts[curr_part++];
88 part->name = "loader";
89 part->offset = trx.offset[i];
90 i++;
91 }
92
93 if (trx.offset[i]) {
94 part = &parts[curr_part++];
95 part->name = "linux";
96 part->offset = trx.offset[i];
97 i++;
98 }
99
100 if (trx.offset[i]) {
101 part = &parts[curr_part++];
102 part->name = parser_trx_data_part_name(mtd, trx.offset[i]);
103 part->offset = trx.offset[i];
104 i++;
105 }
106
107 /*
108 * Assume that every partition ends at the beginning of the one it is
109 * followed by.
110 */
111 for (i = 0; i < curr_part; i++) {
112 u64 next_part_offset = (i < curr_part - 1) ?
113 parts[i + 1].offset : mtd->size;
114
115 parts[i].size = next_part_offset - parts[i].offset;
116 }
117
118 *pparts = parts;
119 return i;
120 };
121
122 static const struct of_device_id mtd_parser_trx_of_match_table[] = {
123 { .compatible = "brcm,trx" },
124 {},
125 };
126 MODULE_DEVICE_TABLE(of, mtd_parser_trx_of_match_table);
127
128 static struct mtd_part_parser mtd_parser_trx = {
129 .parse_fn = parser_trx_parse,
130 .name = "trx",
131 .of_match_table = mtd_parser_trx_of_match_table,
132 };
133 module_mtd_part_parser(mtd_parser_trx);
134
135 MODULE_LICENSE("GPL v2");
136 MODULE_DESCRIPTION("Parser for TRX format partitions");
137