aboutsummaryrefslogtreecommitdiff
path: root/drivers/mtd/bcm47xxpart.c
blob: d10fa6c8f074648e0a7ec5e05562e15f4695b849 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
/*
 * BCM47XX MTD partitioning
 *
 * Copyright © 2012 Rafał Miłecki <zajec5@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/bcm47xx_nvram.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>

#include <uapi/linux/magic.h>

/*
 * NAND flash on Netgear R6250 was verified to contain 15 partitions.
 * This will result in allocating too big array for some old devices, but the
 * memory will be freed soon anyway (see mtd_device_parse_register).
 */
#define BCM47XXPART_MAX_PARTS		20

/*
 * Amount of bytes we read when analyzing each block of flash memory.
 * Set it big enough to allow detecting partition and reading important data.
 */
#define BCM47XXPART_BYTES_TO_READ	0x4e8

/* Magics */
#define BOARD_DATA_MAGIC		0x5246504D	/* MPFR */
#define BOARD_DATA_MAGIC2		0xBD0D0BBD
#define CFE_MAGIC			0x43464531	/* 1EFC */
#define FACTORY_MAGIC			0x59544346	/* FCTY */
#define NVRAM_HEADER			0x48534C46	/* FLSH */
#define POT_MAGIC1			0x54544f50	/* POTT */
#define POT_MAGIC2			0x504f		/* OP */
#define ML_MAGIC1			0x39685a42
#define ML_MAGIC2			0x26594131
#define TRX_MAGIC			0x30524448
#define SHSQ_MAGIC			0x71736873	/* shsq (weird ZTE H218N endianness) */
#define UBI_EC_MAGIC			0x23494255	/* UBI# */

struct trx_header {
	uint32_t magic;
	uint32_t length;
	uint32_t crc32;
	uint16_t flags;
	uint16_t version;
	uint32_t offset[3];
} __packed;

static void bcm47xxpart_add_part(struct mtd_partition *part, const char *name,
				 u64 offset, uint32_t mask_flags)
{
	part->name = name;
	part->offset = offset;
	part->mask_flags = mask_flags;
}

static const char *bcm47xxpart_trx_data_part_name(struct mtd_info *master,
						  size_t offset)
{
	uint32_t buf;
	size_t bytes_read;
	int err;

	err  = mtd_read(master, offset, sizeof(buf), &bytes_read,
			(uint8_t *)&buf);
	if (err && !mtd_is_bitflip(err)) {
		pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
			offset, err);
		goto out_default;
	}

	if (buf == UBI_EC_MAGIC)
		return "ubi";

out_default:
	return "rootfs";
}

static int bcm47xxpart_parse_trx(struct mtd_info *master,
				 struct mtd_partition *trx,
				 struct mtd_partition *parts,
				 size_t parts_len)
{
	struct trx_header header;
	size_t bytes_read;
	int curr_part = 0;
	int i, err;

	if (parts_len < 3) {
		pr_warn("No enough space to add TRX partitions!\n");
		return -ENOMEM;
	}

	err = mtd_read(master, trx->offset, sizeof(header), &bytes_read,
		       (uint8_t *)&header);
	if (err && !mtd_is_bitflip(err)) {
		pr_err("mtd_read error while reading TRX header: %d\n", err);
		return err;
	}

	i = 0;

	/* We have LZMA loader if offset[2] points to sth */
	if (header.offset[2]) {
		bcm47xxpart_add_part(&parts[curr_part++], "loader",
				     trx->offset + header.offset[i], 0);
		i++;
	}

	if (header.offset[i]) {
		bcm47xxpart_add_part(&parts[curr_part++], "linux",
				     trx->offset + header.offset[i], 0);
		i++;
	}

	if (header.offset[i]) {
		size_t offset = trx->offset + header.offset[i];
		const char *name = bcm47xxpart_trx_data_part_name(master,
								  offset);

		bcm47xxpart_add_part(&parts[curr_part++], name, offset, 0);
		i++;
	}

	/*
	 * Assume that every partition ends at the beginning of the one it is
	 * followed by.
	 */
	for (i = 0; i < curr_part; i++) {
		u64 next_part_offset = (i < curr_part - 1) ?
					parts[i + 1].offset :
					trx->offset + trx->size;

		parts[i].size = next_part_offset - parts[i].offset;
	}

	return curr_part;
}

/**
 * bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader
 *
 * Some devices may have more than one TRX partition. In such case one of them
 * is the main one and another a failsafe one. Bootloader may fallback to the
 * failsafe firmware if it detects corruption of the main image.
 *
 * This function provides info about currently used TRX partition. It's the one
 * containing kernel started by the bootloader.
 */
static int bcm47xxpart_bootpartition(void)
{
	char buf[4];
	int bootpartition;

	/* Check CFE environment variable */
	if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {
		if (!kstrtoint(buf, 0, &bootpartition))
			return bootpartition;
	}

	return 0;
}

static int bcm47xxpart_parse(struct mtd_info *master,
			     const struct mtd_partition **pparts,
			     struct mtd_part_parser_data *data)
{
	struct mtd_partition *parts;
	uint8_t i, curr_part = 0;
	uint32_t *buf;
	size_t bytes_read;
	uint32_t offset;
	uint32_t blocksize = master->erasesize;
	int trx_parts[2]; /* Array with indexes of TRX partitions */
	int trx_num = 0; /* Number of found TRX partitions */
	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
	int err;

	/*
	 * Some really old flashes (like AT45DB*) had smaller erasesize-s, but
	 * partitions were aligned to at least 0x1000 anyway.
	 */
	if (blocksize < 0x1000)
		blocksize = 0x1000;

	/* Alloc */
	parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
			GFP_KERNEL);
	if (!parts)
		return -ENOMEM;

	buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
	if (!buf) {
		kfree(parts);
		return -ENOMEM;
	}

	/* Parse block by block looking for magics */
	for (offset = 0; offset <= master->size - blocksize;
	     offset += blocksize) {
		/* Nothing more in higher memory on BCM47XX (MIPS) */
		if (IS_ENABLED(CONFIG_BCM47XX) && offset >= 0x2000000)
			break;

		if (curr_part >= BCM47XXPART_MAX_PARTS) {
			pr_warn("Reached maximum number of partitions, scanning stopped!\n");
			break;
		}

		/* Read beginning of the block */
		err = mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
			       &bytes_read, (uint8_t *)buf);
		if (err && !mtd_is_bitflip(err)) {
			pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
			       offset, err);
			continue;
		}

		/* Magic or small NVRAM at 0x400 */
		if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) ||
		    (buf[0x400 / 4] == NVRAM_HEADER)) {
			bcm47xxpart_add_part(&parts[curr_part++], "boot",
					     offset, MTD_WRITEABLE);
			continue;
		}

		/*
		 * board_data starts with board_id which differs across boards,
		 * but we can use 'MPFR' (hopefully) magic at 0x100
		 */
		if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
			bcm47xxpart_add_part(&parts[curr_part++], "board_data",
					     offset, MTD_WRITEABLE);
			continue;
		}

		/* Found on Huawei E970 */
		if (buf[0x000 / 4] == FACTORY_MAGIC) {
			bcm47xxpart_add_part(&parts[curr_part++], "factory",
					     offset, MTD_WRITEABLE);
			continue;
		}

		/* POT(TOP) */
		if (buf[0x000 / 4] == POT_MAGIC1 &&
		    (buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
			bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
					     MTD_WRITEABLE);
			continue;
		}

		/* ML */
		if (buf[0x010 / 4] == ML_MAGIC1 &&
		    buf[0x014 / 4] == ML_MAGIC2) {
			bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
					     MTD_WRITEABLE);
			continue;
		}

		/* TRX */
		if (buf[0x000 / 4] == TRX_MAGIC) {
			struct trx_header *trx;

			if (trx_num >= ARRAY_SIZE(trx_parts))
				pr_warn("No enough space to store another TRX found at 0x%X\n",
					offset);
			else
				trx_parts[trx_num++] = curr_part;
			bcm47xxpart_add_part(&parts[curr_part++], "firmware",
					     offset, 0);

			/* Jump to the end of TRX */
			trx = (struct trx_header *)buf;
			offset = roundup(offset + trx->length, blocksize);
			/* Next loop iteration will increase the offset */
			offset -= blocksize;
			continue;
		}

		/* Squashfs on devices not using TRX */
		if (le32_to_cpu(buf[0x000 / 4]) == SQUASHFS_MAGIC ||
		    buf[0x000 / 4] == SHSQ_MAGIC) {
			bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
					     offset, 0);
			continue;
		}

		/*
		 * New (ARM?) devices may have NVRAM in some middle block. Last
		 * block will be checked later, so skip it.
		 */
		if (offset != master->size - blocksize &&
		    buf[0x000 / 4] == NVRAM_HEADER) {
			bcm47xxpart_add_part(&parts[curr_part++], "nvram",
					     offset, 0);
			continue;
		}

		/* Read middle of the block */
		err = mtd_read(master, offset + 0x8000, 0x4, &bytes_read,
			       (uint8_t *)buf);
		if (err && !mtd_is_bitflip(err)) {
			pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
			       offset, err);
			continue;
		}

		/* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */
		if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {
			bcm47xxpart_add_part(&parts[curr_part++], "board_data",
					     offset, MTD_WRITEABLE);
			continue;
		}
	}

	/* Look for NVRAM at the end of the last block. */
	for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
		if (curr_part >= BCM47XXPART_MAX_PARTS) {
			pr_warn("Reached maximum number of partitions, scanning stopped!\n");
			break;
		}

		offset = master->size - possible_nvram_sizes[i];
		err = mtd_read(master, offset, 0x4, &bytes_read,
			       (uint8_t *)buf);
		if (err && !mtd_is_bitflip(err)) {
			pr_err("mtd_read error while reading (offset 0x%X): %d\n",
			       offset, err);
			continue;
		}

		/* Standard NVRAM */
		if (buf[0] == NVRAM_HEADER) {
			bcm47xxpart_add_part(&parts[curr_part++], "nvram",
					     master->size - blocksize, 0);
			break;
		}
	}

	kfree(buf);

	/*
	 * Assume that partitions end at the beginning of the one they are
	 * followed by.
	 */
	for (i = 0; i < curr_part; i++) {
		u64 next_part_offset = (i < curr_part - 1) ?
				       parts[i + 1].offset : master->size;

		parts[i].size = next_part_offset - parts[i].offset;
	}

	/* If there was TRX parse it now */
	for (i = 0; i < trx_num; i++) {
		struct mtd_partition *trx = &parts[trx_parts[i]];

		if (i == bcm47xxpart_bootpartition()) {
			int num_parts;

			num_parts = bcm47xxpart_parse_trx(master, trx,
							  parts + curr_part,
							  BCM47XXPART_MAX_PARTS - curr_part);
			if (num_parts > 0)
				curr_part += num_parts;
		} else {
			trx->name = "failsafe";
		}
	}

	*pparts = parts;
	return curr_part;
};

static struct mtd_part_parser bcm47xxpart_mtd_parser = {
	.parse_fn = bcm47xxpart_parse,
	.name = "bcm47xxpart",
};
module_mtd_part_parser(bcm47xxpart_mtd_parser);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");