53aebc5987e88257261eb74a35d07bbd650a01cd
[openwrt/openwrt.git] / target / linux / generic / files / drivers / mtd / mtdsplit / mtdsplit_trx.c
1 /*
2 * Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
3 * Copyright (C) 2014 Felix Fietkau <nbd@nbd.name>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published
7 * by the Free Software Foundation.
8 *
9 */
10
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/slab.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/mtd/partitions.h>
19 #include <linux/byteorder/generic.h>
20
21 #include "mtdsplit.h"
22
23 #define TRX_MAGIC 0x30524448 /* "HDR0" */
24
25 struct trx_header {
26 __le32 magic;
27 __le32 len;
28 __le32 crc32;
29 __le32 flag_version;
30 __le32 offset[4];
31 };
32
33 static int
34 read_trx_header(struct mtd_info *mtd, size_t offset,
35 struct trx_header *header)
36 {
37 size_t header_len;
38 size_t retlen;
39 int ret;
40
41 header_len = sizeof(*header);
42 ret = mtd_read(mtd, offset, header_len, &retlen,
43 (unsigned char *) header);
44 if (ret) {
45 pr_debug("read error in \"%s\"\n", mtd->name);
46 return ret;
47 }
48
49 if (retlen != header_len) {
50 pr_debug("short read in \"%s\"\n", mtd->name);
51 return -EIO;
52 }
53
54 return 0;
55 }
56
57 static int
58 mtdsplit_parse_trx(struct mtd_info *master,
59 const struct mtd_partition **pparts,
60 struct mtd_part_parser_data *data)
61 {
62 struct mtd_partition *parts;
63 struct trx_header hdr;
64 int nr_parts;
65 size_t offset;
66 size_t trx_offset;
67 size_t trx_size = 0;
68 size_t rootfs_offset;
69 size_t rootfs_size = 0;
70 int ret;
71
72 nr_parts = 2;
73 parts = kzalloc(nr_parts * sizeof(*parts), GFP_KERNEL);
74 if (!parts)
75 return -ENOMEM;
76
77 /* find trx image on erase block boundaries */
78 for (offset = 0; offset < master->size; offset += master->erasesize) {
79 trx_size = 0;
80
81 ret = read_trx_header(master, offset, &hdr);
82 if (ret)
83 continue;
84
85 if (hdr.magic != cpu_to_le32(TRX_MAGIC)) {
86 pr_debug("no valid trx header found in \"%s\" at offset %llx\n",
87 master->name, (unsigned long long) offset);
88 continue;
89 }
90
91 trx_size = le32_to_cpu(hdr.len);
92 if ((offset + trx_size) > master->size) {
93 pr_debug("trx image exceeds MTD device \"%s\"\n",
94 master->name);
95 continue;
96 }
97 break;
98 }
99
100 if (trx_size == 0) {
101 pr_debug("no trx header found in \"%s\"\n", master->name);
102 ret = -ENODEV;
103 goto err;
104 }
105
106 trx_offset = offset + hdr.offset[0];
107 rootfs_offset = offset + hdr.offset[1];
108 rootfs_size = master->size - rootfs_offset;
109 trx_size = rootfs_offset - trx_offset;
110
111 if (rootfs_size == 0) {
112 pr_debug("no rootfs found in \"%s\"\n", master->name);
113 ret = -ENODEV;
114 goto err;
115 }
116
117 parts[0].name = KERNEL_PART_NAME;
118 parts[0].offset = trx_offset;
119 parts[0].size = trx_size;
120
121 parts[1].name = ROOTFS_PART_NAME;
122 parts[1].offset = rootfs_offset;
123 parts[1].size = rootfs_size;
124
125 *pparts = parts;
126 return nr_parts;
127
128 err:
129 kfree(parts);
130 return ret;
131 }
132
133 static struct mtd_part_parser trx_parser = {
134 .owner = THIS_MODULE,
135 .name = "trx-fw",
136 .parse_fn = mtdsplit_parse_trx,
137 .type = MTD_PARSER_TYPE_FIRMWARE,
138 };
139
140 static int __init mtdsplit_trx_init(void)
141 {
142 register_mtd_parser(&trx_parser);
143
144 return 0;
145 }
146
147 module_init(mtdsplit_trx_init);