1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * BCM47XX MTD partitioning |
4 | * |
5 | * Copyright © 2012 Rafał Miłecki <zajec5@gmail.com> |
6 | */ |
7 | |
8 | #include <linux/bcm47xx_nvram.h> |
9 | #include <linux/module.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/mtd/mtd.h> |
13 | #include <linux/mtd/partitions.h> |
14 | |
15 | #include <uapi/linux/magic.h> |
16 | |
17 | /* |
18 | * NAND flash on Netgear R6250 was verified to contain 15 partitions. |
19 | * This will result in allocating too big array for some old devices, but the |
20 | * memory will be freed soon anyway (see mtd_device_parse_register). |
21 | */ |
22 | #define BCM47XXPART_MAX_PARTS 20 |
23 | |
24 | /* |
25 | * Amount of bytes we read when analyzing each block of flash memory. |
26 | * Set it big enough to allow detecting partition and reading important data. |
27 | */ |
28 | #define BCM47XXPART_BYTES_TO_READ 0x4e8 |
29 | |
30 | /* Magics */ |
31 | #define BOARD_DATA_MAGIC 0x5246504D /* MPFR */ |
32 | #define BOARD_DATA_MAGIC2 0xBD0D0BBD |
33 | #define CFE_MAGIC 0x43464531 /* 1EFC */ |
34 | #define FACTORY_MAGIC 0x59544346 /* FCTY */ |
35 | #define 0x48534C46 /* FLSH */ |
36 | #define POT_MAGIC1 0x54544f50 /* POTT */ |
37 | #define POT_MAGIC2 0x504f /* OP */ |
38 | #define ML_MAGIC1 0x39685a42 |
39 | #define ML_MAGIC2 0x26594131 |
40 | #define TRX_MAGIC 0x30524448 |
41 | #define SHSQ_MAGIC 0x71736873 /* shsq (weird ZTE H218N endianness) */ |
42 | |
43 | static const char * const trx_types[] = { "trx" , NULL }; |
44 | |
45 | struct { |
46 | uint32_t ; |
47 | uint32_t ; |
48 | uint32_t ; |
49 | uint16_t ; |
50 | uint16_t ; |
51 | uint32_t [3]; |
52 | } __packed; |
53 | |
54 | static void bcm47xxpart_add_part(struct mtd_partition *part, const char *name, |
55 | u64 offset, uint32_t mask_flags) |
56 | { |
57 | part->name = name; |
58 | part->offset = offset; |
59 | part->mask_flags = mask_flags; |
60 | } |
61 | |
62 | /** |
63 | * bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader |
64 | * |
65 | * Some devices may have more than one TRX partition. In such case one of them |
66 | * is the main one and another a failsafe one. Bootloader may fallback to the |
67 | * failsafe firmware if it detects corruption of the main image. |
68 | * |
69 | * This function provides info about currently used TRX partition. It's the one |
70 | * containing kernel started by the bootloader. |
71 | */ |
72 | static int bcm47xxpart_bootpartition(void) |
73 | { |
74 | char buf[4]; |
75 | int bootpartition; |
76 | |
77 | /* Check CFE environment variable */ |
78 | if (bcm47xx_nvram_getenv(name: "bootpartition" , val: buf, val_len: sizeof(buf)) > 0) { |
79 | if (!kstrtoint(s: buf, base: 0, res: &bootpartition)) |
80 | return bootpartition; |
81 | } |
82 | |
83 | return 0; |
84 | } |
85 | |
86 | static int bcm47xxpart_parse(struct mtd_info *master, |
87 | const struct mtd_partition **pparts, |
88 | struct mtd_part_parser_data *data) |
89 | { |
90 | struct mtd_partition *parts; |
91 | uint8_t i, curr_part = 0; |
92 | uint32_t *buf; |
93 | size_t bytes_read; |
94 | uint32_t offset; |
95 | uint32_t blocksize = master->erasesize; |
96 | int trx_parts[2]; /* Array with indexes of TRX partitions */ |
97 | int trx_num = 0; /* Number of found TRX partitions */ |
98 | int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, }; |
99 | int err; |
100 | |
101 | /* |
102 | * Some really old flashes (like AT45DB*) had smaller erasesize-s, but |
103 | * partitions were aligned to at least 0x1000 anyway. |
104 | */ |
105 | if (blocksize < 0x1000) |
106 | blocksize = 0x1000; |
107 | |
108 | /* Alloc */ |
109 | parts = kcalloc(BCM47XXPART_MAX_PARTS, size: sizeof(struct mtd_partition), |
110 | GFP_KERNEL); |
111 | if (!parts) |
112 | return -ENOMEM; |
113 | |
114 | buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL); |
115 | if (!buf) { |
116 | kfree(objp: parts); |
117 | return -ENOMEM; |
118 | } |
119 | |
120 | /* Parse block by block looking for magics */ |
121 | for (offset = 0; offset <= master->size - blocksize; |
122 | offset += blocksize) { |
123 | /* Nothing more in higher memory on BCM47XX (MIPS) */ |
124 | if (IS_ENABLED(CONFIG_BCM47XX) && offset >= 0x2000000) |
125 | break; |
126 | |
127 | if (curr_part >= BCM47XXPART_MAX_PARTS) { |
128 | pr_warn("Reached maximum number of partitions, scanning stopped!\n" ); |
129 | break; |
130 | } |
131 | |
132 | /* Read beginning of the block */ |
133 | err = mtd_read(mtd: master, from: offset, BCM47XXPART_BYTES_TO_READ, |
134 | retlen: &bytes_read, buf: (uint8_t *)buf); |
135 | if (err && !mtd_is_bitflip(err)) { |
136 | pr_err("mtd_read error while parsing (offset: 0x%X): %d\n" , |
137 | offset, err); |
138 | continue; |
139 | } |
140 | |
141 | /* Magic or small NVRAM at 0x400 */ |
142 | if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) || |
143 | (buf[0x400 / 4] == NVRAM_HEADER)) { |
144 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "boot" , |
145 | offset, MTD_WRITEABLE); |
146 | continue; |
147 | } |
148 | |
149 | /* |
150 | * board_data starts with board_id which differs across boards, |
151 | * but we can use 'MPFR' (hopefully) magic at 0x100 |
152 | */ |
153 | if (buf[0x100 / 4] == BOARD_DATA_MAGIC) { |
154 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "board_data" , |
155 | offset, MTD_WRITEABLE); |
156 | continue; |
157 | } |
158 | |
159 | /* Found on Huawei E970 */ |
160 | if (buf[0x000 / 4] == FACTORY_MAGIC) { |
161 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "factory" , |
162 | offset, MTD_WRITEABLE); |
163 | continue; |
164 | } |
165 | |
166 | /* POT(TOP) */ |
167 | if (buf[0x000 / 4] == POT_MAGIC1 && |
168 | (buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) { |
169 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "POT" , offset, |
170 | MTD_WRITEABLE); |
171 | continue; |
172 | } |
173 | |
174 | /* ML */ |
175 | if (buf[0x010 / 4] == ML_MAGIC1 && |
176 | buf[0x014 / 4] == ML_MAGIC2) { |
177 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "ML" , offset, |
178 | MTD_WRITEABLE); |
179 | continue; |
180 | } |
181 | |
182 | /* TRX */ |
183 | if (buf[0x000 / 4] == TRX_MAGIC) { |
184 | struct trx_header *trx; |
185 | uint32_t last_subpart; |
186 | uint32_t trx_size; |
187 | |
188 | if (trx_num >= ARRAY_SIZE(trx_parts)) |
189 | pr_warn("No enough space to store another TRX found at 0x%X\n" , |
190 | offset); |
191 | else |
192 | trx_parts[trx_num++] = curr_part; |
193 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "firmware" , |
194 | offset, mask_flags: 0); |
195 | |
196 | /* |
197 | * Try to find TRX size. The "length" field isn't fully |
198 | * reliable as it could be decreased to make CRC32 cover |
199 | * only part of TRX data. It's commonly used as checksum |
200 | * can't cover e.g. ever-changing rootfs partition. |
201 | * Use offsets as helpers for assuming min TRX size. |
202 | */ |
203 | trx = (struct trx_header *)buf; |
204 | last_subpart = max3(trx->offset[0], trx->offset[1], |
205 | trx->offset[2]); |
206 | trx_size = max(trx->length, last_subpart + blocksize); |
207 | |
208 | /* |
209 | * Skip the TRX data. Decrease offset by block size as |
210 | * the next loop iteration will increase it. |
211 | */ |
212 | offset += roundup(trx_size, blocksize) - blocksize; |
213 | continue; |
214 | } |
215 | |
216 | /* Squashfs on devices not using TRX */ |
217 | if (le32_to_cpu(buf[0x000 / 4]) == SQUASHFS_MAGIC || |
218 | buf[0x000 / 4] == SHSQ_MAGIC) { |
219 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "rootfs" , |
220 | offset, mask_flags: 0); |
221 | continue; |
222 | } |
223 | |
224 | /* |
225 | * New (ARM?) devices may have NVRAM in some middle block. Last |
226 | * block will be checked later, so skip it. |
227 | */ |
228 | if (offset != master->size - blocksize && |
229 | buf[0x000 / 4] == NVRAM_HEADER) { |
230 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "nvram" , |
231 | offset, mask_flags: 0); |
232 | continue; |
233 | } |
234 | |
235 | /* Read middle of the block */ |
236 | err = mtd_read(mtd: master, from: offset + (blocksize / 2), len: 0x4, retlen: &bytes_read, |
237 | buf: (uint8_t *)buf); |
238 | if (err && !mtd_is_bitflip(err)) { |
239 | pr_err("mtd_read error while parsing (offset: 0x%X): %d\n" , |
240 | offset + (blocksize / 2), err); |
241 | continue; |
242 | } |
243 | |
244 | /* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */ |
245 | if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) { |
246 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "board_data" , |
247 | offset, MTD_WRITEABLE); |
248 | continue; |
249 | } |
250 | } |
251 | |
252 | /* Look for NVRAM at the end of the last block. */ |
253 | for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) { |
254 | if (curr_part >= BCM47XXPART_MAX_PARTS) { |
255 | pr_warn("Reached maximum number of partitions, scanning stopped!\n" ); |
256 | break; |
257 | } |
258 | |
259 | offset = master->size - possible_nvram_sizes[i]; |
260 | err = mtd_read(mtd: master, from: offset, len: 0x4, retlen: &bytes_read, |
261 | buf: (uint8_t *)buf); |
262 | if (err && !mtd_is_bitflip(err)) { |
263 | pr_err("mtd_read error while reading (offset 0x%X): %d\n" , |
264 | offset, err); |
265 | continue; |
266 | } |
267 | |
268 | /* Standard NVRAM */ |
269 | if (buf[0] == NVRAM_HEADER) { |
270 | bcm47xxpart_add_part(part: &parts[curr_part++], name: "nvram" , |
271 | offset: master->size - blocksize, mask_flags: 0); |
272 | break; |
273 | } |
274 | } |
275 | |
276 | kfree(objp: buf); |
277 | |
278 | /* |
279 | * Assume that partitions end at the beginning of the one they are |
280 | * followed by. |
281 | */ |
282 | for (i = 0; i < curr_part; i++) { |
283 | u64 next_part_offset = (i < curr_part - 1) ? |
284 | parts[i + 1].offset : master->size; |
285 | |
286 | parts[i].size = next_part_offset - parts[i].offset; |
287 | } |
288 | |
289 | /* If there was TRX parse it now */ |
290 | for (i = 0; i < trx_num; i++) { |
291 | struct mtd_partition *trx = &parts[trx_parts[i]]; |
292 | |
293 | if (i == bcm47xxpart_bootpartition()) |
294 | trx->types = trx_types; |
295 | else |
296 | trx->name = "failsafe" ; |
297 | } |
298 | |
299 | *pparts = parts; |
300 | return curr_part; |
301 | }; |
302 | |
303 | static const struct of_device_id bcm47xxpart_of_match_table[] = { |
304 | { .compatible = "brcm,bcm947xx-cfe-partitions" }, |
305 | {}, |
306 | }; |
307 | MODULE_DEVICE_TABLE(of, bcm47xxpart_of_match_table); |
308 | |
309 | static struct mtd_part_parser bcm47xxpart_mtd_parser = { |
310 | .parse_fn = bcm47xxpart_parse, |
311 | .name = "bcm47xxpart" , |
312 | .of_match_table = bcm47xxpart_of_match_table, |
313 | }; |
314 | module_mtd_part_parser(bcm47xxpart_mtd_parser); |
315 | |
316 | MODULE_LICENSE("GPL" ); |
317 | MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories" ); |
318 | |