summaryrefslogtreecommitdiffstats
path: root/linux_mtd.c
blob: 04eccde27387877d6b58f233e820128c77dba057 (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
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
/*
 * This file is part of the flashrom project.
 *
 * Copyright 2015 Google Inc.
 * Copyright 2018-present Facebook, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <mtd/mtd-user.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <unistd.h>

#include "flash.h"
#include "programmer.h"

#define LINUX_DEV_ROOT			"/dev"
#define LINUX_MTD_SYSFS_ROOT		"/sys/class/mtd"

struct linux_mtd_data {
	FILE *dev_fp;
	int device_is_writeable;
	int no_erase;
	/* Size info is presented in bytes in sysfs. */
	unsigned long int total_size;
	unsigned long int numeraseregions;
	/* only valid if numeraseregions is 0 */
	unsigned long int erasesize;
};

/* read a string from a sysfs file and sanitize it */
static int read_sysfs_string(const char *sysfs_path, const char *filename, char *buf, int len)
{
	int i;
	size_t bytes_read;
	FILE *fp;
	char path[strlen(LINUX_MTD_SYSFS_ROOT) + 32];

	snprintf(path, sizeof(path), "%s/%s", sysfs_path, filename);

	if ((fp = fopen(path, "r")) == NULL) {
		msg_perr("Cannot open %s\n", path);
		return 1;
	}

	clearerr(fp);
	bytes_read = fread(buf, 1, (size_t)len, fp);
	if (!feof(fp) && ferror(fp)) {
		msg_perr("Error occurred when reading %s\n", path);
		fclose(fp);
		return 1;
	}

	buf[bytes_read] = '\0';

	/*
	 * Files from sysfs sometimes contain a newline or other garbage that
	 * can confuse functions like strtoul() and ruin formatting in print
	 * statements. Replace the first non-printable character (space is
	 * considered printable) with a proper string terminator.
	 */
	for (i = 0; i < len; i++) {
		if (!isprint(buf[i])) {
			buf[i] = '\0';
			break;
		}
	}

	fclose(fp);
	return 0;
}

static int read_sysfs_int(const char *sysfs_path, const char *filename, unsigned long int *val)
{
	char buf[32];
	char *endptr;

	if (read_sysfs_string(sysfs_path, filename, buf, sizeof(buf)))
		return 1;

	errno = 0;
	*val = strtoul(buf, &endptr, 0);
	if (*endptr != '\0') {
		msg_perr("Error reading %s\n", filename);
		return 1;
	}

	if (errno) {
		msg_perr("Error reading %s: %s\n", filename, strerror(errno));
		return 1;
	}

	return 0;
}

static int popcnt(unsigned int u)
{
	int count = 0;

	while (u) {
		u &= u - 1;
		count++;
	}

	return count;
}

/* returns 0 to indicate success, non-zero to indicate error */
static int get_mtd_info(const char *sysfs_path, struct linux_mtd_data *data)
{
	unsigned long int tmp;
	char device_name[32];

	/* Flags */
	if (read_sysfs_int(sysfs_path, "flags", &tmp))
		return 1;
	if (tmp & MTD_WRITEABLE) {
		/* cache for later use by write function */
		data->device_is_writeable = 1;
	}
	if (tmp & MTD_NO_ERASE) {
		data->no_erase = 1;
	}

	/* Device name */
	if (read_sysfs_string(sysfs_path, "name", device_name, sizeof(device_name)))
		return 1;

	/* Total size */
	if (read_sysfs_int(sysfs_path, "size", &data->total_size))
		return 1;
	if (popcnt(data->total_size) != 1) {
		msg_perr("MTD size is not a power of 2\n");
		return 1;
	}

	/* Erase size */
	if (read_sysfs_int(sysfs_path, "erasesize", &data->erasesize))
		return 1;
	if (popcnt(data->erasesize) != 1) {
		msg_perr("MTD erase size is not a power of 2\n");
		return 1;
	}

	/* Erase regions */
	if (read_sysfs_int(sysfs_path, "numeraseregions", &data->numeraseregions))
		return 1;
	if (data->numeraseregions != 0) {
		msg_perr("Non-uniform eraseblock size is unsupported.\n");
		return 1;
	}

	msg_pdbg("%s: device_name: \"%s\", is_writeable: %d, "
		"numeraseregions: %lu, total_size: %lu, erasesize: %lu\n",
		__func__, device_name, data->device_is_writeable,
		data->numeraseregions, data->total_size, data->erasesize);

	return 0;
}

static int linux_mtd_probe(struct flashctx *flash)
{
	struct linux_mtd_data *data = flash->mst->opaque.data;

	if (data->no_erase)
		flash->chip->feature_bits |= FEATURE_NO_ERASE;
	flash->chip->tested = TEST_OK_PREW;
	flash->chip->total_size = data->total_size / 1024;	/* bytes -> kB */
	flash->chip->block_erasers[0].eraseblocks[0].size = data->erasesize;
	flash->chip->block_erasers[0].eraseblocks[0].count =
		data->total_size / data->erasesize;
	return 1;
}

static int linux_mtd_read(struct flashctx *flash, uint8_t *buf,
			  unsigned int start, unsigned int len)
{
	struct linux_mtd_data *data = flash->mst->opaque.data;
	unsigned int eb_size = flash->chip->block_erasers[0].eraseblocks[0].size;
	unsigned int i;

	if (fseek(data->dev_fp, start, SEEK_SET) != 0) {
		msg_perr("Cannot seek to 0x%06x: %s\n", start, strerror(errno));
		return 1;
	}

	for (i = 0; i < len; ) {
		/*
		 * Try to align reads to eraseblock size.
		 * FIXME: Shouldn't actually be necessary, but not all MTD
		 * drivers handle arbitrary large reads well.
		 */
		unsigned int step = eb_size - ((start + i) % eb_size);
		step = min(step, len - i);

		if (fread(buf + i, step, 1, data->dev_fp) != 1) {
			msg_perr("Cannot read 0x%06x bytes at 0x%06x: %s\n",
					step, start + i, strerror(errno));
			return 1;
		}

		i += step;
	}

	return 0;
}

/* this version assumes we must divide the write request into chunks ourselves */
static int linux_mtd_write(struct flashctx *flash, const uint8_t *buf,
				unsigned int start, unsigned int len)
{
	struct linux_mtd_data *data = flash->mst->opaque.data;
	unsigned int chunksize = flash->chip->block_erasers[0].eraseblocks[0].size;
	unsigned int i;

	if (!data->device_is_writeable)
		return 1;

	if (fseek(data->dev_fp, start, SEEK_SET) != 0) {
		msg_perr("Cannot seek to 0x%06x: %s\n", start, strerror(errno));
		return 1;
	}

	/*
	 * Try to align writes to eraseblock size. We want these large enough
	 * to give MTD room for optimizing performance.
	 * FIXME: Shouldn't need to divide this up at all, but not all MTD
	 * drivers handle arbitrary large writes well.
	 */
	for (i = 0; i < len; ) {
		unsigned int step = chunksize - ((start + i) % chunksize);
		step = min(step, len - i);

		if (fwrite(buf + i, step, 1, data->dev_fp) != 1) {
			msg_perr("Cannot write 0x%06x bytes at 0x%06x\n", step, start + i);
			return 1;
		}

		if (fflush(data->dev_fp) == EOF) {
			msg_perr("Failed to flush buffer: %s\n", strerror(errno));
			return 1;
		}

		i += step;
	}

	return 0;
}

static int linux_mtd_erase(struct flashctx *flash,
			unsigned int start, unsigned int len)
{
	struct linux_mtd_data *data = flash->mst->opaque.data;
	uint32_t u;

	if (data->no_erase) {
		msg_perr("%s: device does not support erasing. Please file a "
				"bug report at flashrom@flashrom.org\n", __func__);
		return 1;
	}

	if (data->numeraseregions != 0) {
		/* TODO: Support non-uniform eraseblock size using
		   use MEMGETREGIONCOUNT/MEMGETREGIONINFO ioctls */
		msg_perr("%s: numeraseregions must be 0\n", __func__);
		return 1;
	}

	for (u = 0; u < len; u += data->erasesize) {
		struct erase_info_user erase_info = {
			.start = start + u,
			.length = data->erasesize,
		};

		if (ioctl(fileno(data->dev_fp), MEMERASE, &erase_info) == -1) {
			msg_perr("%s: ioctl: %s\n", __func__, strerror(errno));
			return 1;
		}
	}

	return 0;
}

static int linux_mtd_shutdown(void *data)
{
	struct linux_mtd_data *mtd_data = data;
	if (mtd_data->dev_fp != NULL) {
		fclose(mtd_data->dev_fp);
	}
	free(data);

	return 0;
}

static const struct opaque_master linux_mtd_opaque_master = {
	/* max_data_{read,write} don't have any effect for this programmer */
	.max_data_read	= MAX_DATA_UNSPECIFIED,
	.max_data_write	= MAX_DATA_UNSPECIFIED,
	.probe		= linux_mtd_probe,
	.read		= linux_mtd_read,
	.write		= linux_mtd_write,
	.erase		= linux_mtd_erase,
	.shutdown	= linux_mtd_shutdown,
};

/* Returns 0 if setup is successful, non-zero to indicate error */
static int linux_mtd_setup(int dev_num, struct linux_mtd_data *data)
{
	char sysfs_path[32];
	int ret = 1;

	/* Start by checking /sys/class/mtd/mtdN/type which should be "nor" for NOR flash */
	if (snprintf(sysfs_path, sizeof(sysfs_path), "%s/mtd%d/", LINUX_MTD_SYSFS_ROOT, dev_num) < 0)
		goto linux_mtd_setup_exit;

	char buf[4] = { 0 };
	if (read_sysfs_string(sysfs_path, "type", buf, sizeof(buf)))
		return 1;

	if (strcmp(buf, "nor")) {
		msg_perr("MTD device %d type is not \"nor\"\n", dev_num);
		goto linux_mtd_setup_exit;
	}

	/* sysfs shows the correct device type, see if corresponding device node exists */
	char dev_path[32];
	struct stat s;
	snprintf(dev_path, sizeof(dev_path), "%s/mtd%d", LINUX_DEV_ROOT, dev_num);
	errno = 0;
	if (stat(dev_path, &s) < 0) {
		msg_pdbg("Cannot stat \"%s\": %s\n", dev_path, strerror(errno));
		goto linux_mtd_setup_exit;
	}

	/* so far so good, get more info from other files in this dir */
	if (snprintf(sysfs_path, sizeof(sysfs_path), "%s/mtd%d/", LINUX_MTD_SYSFS_ROOT, dev_num) < 0)
		goto linux_mtd_setup_exit;
	if (get_mtd_info(sysfs_path, data))
		goto linux_mtd_setup_exit;

	/* open file stream and go! */
	if ((data->dev_fp = fopen(dev_path, "r+")) == NULL) {
		msg_perr("Cannot open file stream for %s\n", dev_path);
		goto linux_mtd_setup_exit;
	}
	ret = setvbuf(data->dev_fp, NULL, _IONBF, 0);
	if (ret)
		msg_pwarn("Failed to set MTD device to unbuffered: %d\n", ret);

	msg_pinfo("Opened %s successfully\n", dev_path);

	ret = 0;
linux_mtd_setup_exit:
	return ret;
}

static int linux_mtd_init(void)
{
	char *param;
	int dev_num = 0;
	int ret = 1;
	struct linux_mtd_data *data = NULL;

	param = extract_programmer_param("dev");
	if (param) {
		char *endptr;

		dev_num = strtol(param, &endptr, 0);
		if ((*endptr != '\0') || (dev_num < 0)) {
			msg_perr("Invalid device number %s. Use flashrom -p "
				"linux_mtd:dev=N where N is a valid MTD\n"
				"device number.\n", param);
			goto linux_mtd_init_exit;
		}
	}

	/*
	 * If user specified the MTD device number then error out if it doesn't
	 * appear to exist. Otherwise assume the error is benign and print a
	 * debug message. Bail out in either case.
	 */
	char sysfs_path[32];
	if (snprintf(sysfs_path, sizeof(sysfs_path), "%s/mtd%d", LINUX_MTD_SYSFS_ROOT, dev_num) < 0)
		goto linux_mtd_init_exit;

	struct stat s;
	if (stat(sysfs_path, &s) < 0) {
		if (param)
			msg_perr("%s does not exist\n", sysfs_path);
		else
			msg_pdbg("%s does not exist\n", sysfs_path);
		goto linux_mtd_init_exit;
	}
	free(param);

	data = calloc(1, sizeof(*data));
	if (!data) {
		msg_perr("Unable to allocate memory for linux_mtd_data\n");
		return 1;
	}

	/* Get MTD info and store it in `data` */
	if (linux_mtd_setup(dev_num, data)) {
		free(data);
		return 1;
	}

	return register_opaque_master(&linux_mtd_opaque_master, data);

linux_mtd_init_exit:
	free(param);
	return ret;
}

const struct programmer_entry programmer_linux_mtd = {
	.name			= "linux_mtd",
	.type			= OTHER,
	.devs.note		= "Device files /dev/mtd*\n",
	.init			= linux_mtd_init,
	.map_flash_region	= fallback_map,
	.unmap_flash_region	= fallback_unmap,
	.delay			= internal_delay,
};