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3cf7f131 RM |
1 | /* |
2 | * BCM47XX MTD partitioning | |
3 | * | |
4 | * Copyright © 2012 Rafał Miłecki <zajec5@gmail.com> | |
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/kernel.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/mtd/mtd.h> | |
16 | #include <linux/mtd/partitions.h> | |
17 | #include <asm/mach-bcm47xx/nvram.h> | |
18 | ||
19 | /* 10 parts were found on sflash on Netgear WNDR4500 */ | |
20 | #define BCM47XXPART_MAX_PARTS 12 | |
21 | ||
22 | /* | |
23 | * Amount of bytes we read when analyzing each block of flash memory. | |
24 | * Set it big enough to allow detecting partition and reading important data. | |
25 | */ | |
26 | #define BCM47XXPART_BYTES_TO_READ 0x404 | |
27 | ||
28 | /* Magics */ | |
29 | #define BOARD_DATA_MAGIC 0x5246504D /* MPFR */ | |
30 | #define POT_MAGIC1 0x54544f50 /* POTT */ | |
31 | #define POT_MAGIC2 0x504f /* OP */ | |
32 | #define ML_MAGIC1 0x39685a42 | |
33 | #define ML_MAGIC2 0x26594131 | |
34 | #define TRX_MAGIC 0x30524448 | |
35 | ||
36 | struct trx_header { | |
37 | uint32_t magic; | |
38 | uint32_t length; | |
39 | uint32_t crc32; | |
40 | uint16_t flags; | |
41 | uint16_t version; | |
42 | uint32_t offset[3]; | |
43 | } __packed; | |
44 | ||
45 | static void bcm47xxpart_add_part(struct mtd_partition *part, char *name, | |
46 | u64 offset, uint32_t mask_flags) | |
47 | { | |
48 | part->name = name; | |
49 | part->offset = offset; | |
50 | part->mask_flags = mask_flags; | |
51 | } | |
52 | ||
53 | static int bcm47xxpart_parse(struct mtd_info *master, | |
54 | struct mtd_partition **pparts, | |
55 | struct mtd_part_parser_data *data) | |
56 | { | |
57 | struct mtd_partition *parts; | |
58 | uint8_t i, curr_part = 0; | |
59 | uint32_t *buf; | |
60 | size_t bytes_read; | |
61 | uint32_t offset; | |
62 | uint32_t blocksize = 0x10000; | |
63 | struct trx_header *trx; | |
64 | ||
65 | /* Alloc */ | |
66 | parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS, | |
67 | GFP_KERNEL); | |
68 | buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL); | |
69 | ||
70 | /* Parse block by block looking for magics */ | |
71 | for (offset = 0; offset <= master->size - blocksize; | |
72 | offset += blocksize) { | |
73 | /* Nothing more in higher memory */ | |
74 | if (offset >= 0x2000000) | |
75 | break; | |
76 | ||
77 | if (curr_part > BCM47XXPART_MAX_PARTS) { | |
78 | pr_warn("Reached maximum number of partitions, scanning stopped!\n"); | |
79 | break; | |
80 | } | |
81 | ||
82 | /* Read beginning of the block */ | |
83 | if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ, | |
84 | &bytes_read, (uint8_t *)buf) < 0) { | |
85 | pr_err("mtd_read error while parsing (offset: 0x%X)!\n", | |
86 | offset); | |
87 | continue; | |
88 | } | |
89 | ||
90 | /* CFE has small NVRAM at 0x400 */ | |
91 | if (buf[0x400 / 4] == NVRAM_HEADER) { | |
92 | bcm47xxpart_add_part(&parts[curr_part++], "boot", | |
93 | offset, MTD_WRITEABLE); | |
94 | continue; | |
95 | } | |
96 | ||
97 | /* Standard NVRAM */ | |
98 | if (buf[0x000 / 4] == NVRAM_HEADER) { | |
99 | bcm47xxpart_add_part(&parts[curr_part++], "nvram", | |
100 | offset, 0); | |
101 | continue; | |
102 | } | |
103 | ||
104 | /* | |
105 | * board_data starts with board_id which differs across boards, | |
106 | * but we can use 'MPFR' (hopefully) magic at 0x100 | |
107 | */ | |
108 | if (buf[0x100 / 4] == BOARD_DATA_MAGIC) { | |
109 | bcm47xxpart_add_part(&parts[curr_part++], "board_data", | |
110 | offset, MTD_WRITEABLE); | |
111 | continue; | |
112 | } | |
113 | ||
114 | /* POT(TOP) */ | |
115 | if (buf[0x000 / 4] == POT_MAGIC1 && | |
116 | (buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) { | |
117 | bcm47xxpart_add_part(&parts[curr_part++], "POT", offset, | |
118 | MTD_WRITEABLE); | |
119 | continue; | |
120 | } | |
121 | ||
122 | /* ML */ | |
123 | if (buf[0x010 / 4] == ML_MAGIC1 && | |
124 | buf[0x014 / 4] == ML_MAGIC2) { | |
125 | bcm47xxpart_add_part(&parts[curr_part++], "ML", offset, | |
126 | MTD_WRITEABLE); | |
127 | continue; | |
128 | } | |
129 | ||
130 | /* TRX */ | |
131 | if (buf[0x000 / 4] == TRX_MAGIC) { | |
132 | trx = (struct trx_header *)buf; | |
133 | ||
134 | i = 0; | |
135 | /* We have LZMA loader if offset[2] points to sth */ | |
136 | if (trx->offset[2]) { | |
137 | bcm47xxpart_add_part(&parts[curr_part++], | |
138 | "loader", | |
139 | offset + trx->offset[i], | |
140 | 0); | |
141 | i++; | |
142 | } | |
143 | ||
144 | bcm47xxpart_add_part(&parts[curr_part++], "linux", | |
145 | offset + trx->offset[i], 0); | |
146 | i++; | |
147 | ||
148 | /* | |
149 | * Pure rootfs size is known and can be calculated as: | |
150 | * trx->length - trx->offset[i]. We don't fill it as | |
151 | * we want to have jffs2 (overlay) in the same mtd. | |
152 | */ | |
153 | bcm47xxpart_add_part(&parts[curr_part++], "rootfs", | |
154 | offset + trx->offset[i], 0); | |
155 | i++; | |
156 | ||
157 | /* | |
158 | * We have whole TRX scanned, skip to the next part. Use | |
159 | * roundown (not roundup), as the loop will increase | |
160 | * offset in next step. | |
161 | */ | |
162 | offset = rounddown(offset + trx->length, blocksize); | |
163 | continue; | |
164 | } | |
165 | } | |
166 | kfree(buf); | |
167 | ||
168 | /* | |
169 | * Assume that partitions end at the beginning of the one they are | |
170 | * followed by. | |
171 | */ | |
172 | for (i = 0; i < curr_part - 1; i++) | |
173 | parts[i].size = parts[i + 1].offset - parts[i].offset; | |
174 | if (curr_part > 0) | |
175 | parts[curr_part - 1].size = | |
176 | master->size - parts[curr_part - 1].offset; | |
177 | ||
178 | *pparts = parts; | |
179 | return curr_part; | |
180 | }; | |
181 | ||
182 | static struct mtd_part_parser bcm47xxpart_mtd_parser = { | |
183 | .owner = THIS_MODULE, | |
184 | .parse_fn = bcm47xxpart_parse, | |
185 | .name = "bcm47xxpart", | |
186 | }; | |
187 | ||
188 | static int __init bcm47xxpart_init(void) | |
189 | { | |
190 | return register_mtd_parser(&bcm47xxpart_mtd_parser); | |
191 | } | |
192 | ||
193 | static void __exit bcm47xxpart_exit(void) | |
194 | { | |
195 | deregister_mtd_parser(&bcm47xxpart_mtd_parser); | |
196 | } | |
197 | ||
198 | module_init(bcm47xxpart_init); | |
199 | module_exit(bcm47xxpart_exit); | |
200 | ||
201 | MODULE_LICENSE("GPL"); | |
202 | MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories"); |