summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/devices/sst25l.c
blob: 175c5233f29fe608e32d198376bc756aa010686a (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
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
/*
 * sst25l.c
 *
 * Driver for SST25L SPI Flash chips
 *
 * Copyright © 2009 Bluewater Systems Ltd
 * Author: Andre Renaud <andre@bluewatersys.com>
 * Author: Ryan Mallon <ryan@bluewatersys.com>
 *
 * Based on m25p80.c
 *
 * This code 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/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/sched.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>

#include <linux/spi/spi.h>
#include <linux/spi/flash.h>

/* Erases can take up to 3 seconds! */
#define MAX_READY_WAIT_JIFFIES	msecs_to_jiffies(3000)

#define SST25L_CMD_WRSR		0x01	/* Write status register */
#define SST25L_CMD_WRDI		0x04	/* Write disable */
#define SST25L_CMD_RDSR		0x05	/* Read status register */
#define SST25L_CMD_WREN		0x06	/* Write enable */
#define SST25L_CMD_READ		0x03	/* High speed read */

#define SST25L_CMD_EWSR		0x50	/* Enable write status register */
#define SST25L_CMD_SECTOR_ERASE	0x20	/* Erase sector */
#define SST25L_CMD_READ_ID	0x90	/* Read device ID */
#define SST25L_CMD_AAI_PROGRAM	0xaf	/* Auto address increment */

#define SST25L_STATUS_BUSY	(1 << 0)	/* Chip is busy */
#define SST25L_STATUS_WREN	(1 << 1)	/* Write enabled */
#define SST25L_STATUS_BP0	(1 << 2)	/* Block protection 0 */
#define SST25L_STATUS_BP1	(1 << 3)	/* Block protection 1 */

struct sst25l_flash {
	struct spi_device	*spi;
	struct mutex		lock;
	struct mtd_info		mtd;

	int 			partitioned;
};

struct flash_info {
	const char		*name;
	uint16_t		device_id;
	unsigned		page_size;
	unsigned		nr_pages;
	unsigned		erase_size;
};

#define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)

static struct flash_info __initdata sst25l_flash_info[] = {
	{"sst25lf020a", 0xbf43, 256, 1024, 4096},
	{"sst25lf040a",	0xbf44,	256, 2048, 4096},
};

static int sst25l_status(struct sst25l_flash *flash, int *status)
{
	unsigned char command, response;
	int err;

	command = SST25L_CMD_RDSR;
	err = spi_write_then_read(flash->spi, &command, 1, &response, 1);
	if (err < 0)
		return err;

	*status = response;
	return 0;
}

static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
{
	unsigned char command[2];
	int status, err;

	command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
	err = spi_write(flash->spi, command, 1);
	if (err)
		return err;

	command[0] = SST25L_CMD_EWSR;
	err = spi_write(flash->spi, command, 1);
	if (err)
		return err;

	command[0] = SST25L_CMD_WRSR;
	command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
	err = spi_write(flash->spi, command, 2);
	if (err)
		return err;

	if (enable) {
		err = sst25l_status(flash, &status);
		if (err)
			return err;
		if (!(status & SST25L_STATUS_WREN))
			return -EROFS;
	}

	return 0;
}

static int sst25l_wait_till_ready(struct sst25l_flash *flash)
{
	unsigned long deadline;
	int status, err;

	deadline = jiffies + MAX_READY_WAIT_JIFFIES;
	do {
		err = sst25l_status(flash, &status);
		if (err)
			return err;
		if (!(status & SST25L_STATUS_BUSY))
			return 0;

		cond_resched();
	} while (!time_after_eq(jiffies, deadline));

	return -ETIMEDOUT;
}

static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
{
	unsigned char command[4];
	int err;

	err = sst25l_write_enable(flash, 1);
	if (err)
		return err;

	command[0] = SST25L_CMD_SECTOR_ERASE;
	command[1] = offset >> 16;
	command[2] = offset >> 8;
	command[3] = offset;
	err = spi_write(flash->spi, command, 4);
	if (err)
		return err;

	err = sst25l_wait_till_ready(flash);
	if (err)
		return err;

	return sst25l_write_enable(flash, 0);
}

static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct sst25l_flash *flash = to_sst25l_flash(mtd);
	uint32_t addr, end;
	int err;

	/* Sanity checks */
	if (instr->addr + instr->len > flash->mtd.size)
		return -EINVAL;

	if ((uint32_t)instr->len % mtd->erasesize)
		return -EINVAL;

	if ((uint32_t)instr->addr % mtd->erasesize)
		return -EINVAL;

	addr = instr->addr;
	end = addr + instr->len;

	mutex_lock(&flash->lock);

	err = sst25l_wait_till_ready(flash);
	if (err) {
		mutex_unlock(&flash->lock);
		return err;
	}

	while (addr < end) {
		err = sst25l_erase_sector(flash, addr);
		if (err) {
			mutex_unlock(&flash->lock);
			instr->state = MTD_ERASE_FAILED;
			dev_err(&flash->spi->dev, "Erase failed\n");
			return err;
		}

		addr += mtd->erasesize;
	}

	mutex_unlock(&flash->lock);

	instr->state = MTD_ERASE_DONE;
	mtd_erase_callback(instr);
	return 0;
}

static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
		       size_t *retlen, unsigned char *buf)
{
	struct sst25l_flash *flash = to_sst25l_flash(mtd);
	struct spi_transfer transfer[2];
	struct spi_message message;
	unsigned char command[4];
	int ret;

	/* Sanity checking */
	if (len == 0)
		return 0;

	if (from + len > flash->mtd.size)
		return -EINVAL;

	if (retlen)
		*retlen = 0;

	spi_message_init(&message);
	memset(&transfer, 0, sizeof(transfer));

	command[0] = SST25L_CMD_READ;
	command[1] = from >> 16;
	command[2] = from >> 8;
	command[3] = from;

	transfer[0].tx_buf = command;
	transfer[0].len = sizeof(command);
	spi_message_add_tail(&transfer[0], &message);

	transfer[1].rx_buf = buf;
	transfer[1].len = len;
	spi_message_add_tail(&transfer[1], &message);

	mutex_lock(&flash->lock);

	/* Wait for previous write/erase to complete */
	ret = sst25l_wait_till_ready(flash);
	if (ret) {
		mutex_unlock(&flash->lock);
		return ret;
	}

	spi_sync(flash->spi, &message);

	if (retlen && message.actual_length > sizeof(command))
		*retlen += message.actual_length - sizeof(command);

	mutex_unlock(&flash->lock);
	return 0;
}

static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
			size_t *retlen, const unsigned char *buf)
{
	struct sst25l_flash *flash = to_sst25l_flash(mtd);
	int i, j, ret, bytes, copied = 0;
	unsigned char command[5];

	/* Sanity checks */
	if (!len)
		return 0;

	if (to + len > flash->mtd.size)
		return -EINVAL;

	if ((uint32_t)to % mtd->writesize)
		return -EINVAL;

	mutex_lock(&flash->lock);

	ret = sst25l_write_enable(flash, 1);
	if (ret)
		goto out;

	for (i = 0; i < len; i += mtd->writesize) {
		ret = sst25l_wait_till_ready(flash);
		if (ret)
			goto out;

		/* Write the first byte of the page */
		command[0] = SST25L_CMD_AAI_PROGRAM;
		command[1] = (to + i) >> 16;
		command[2] = (to + i) >> 8;
		command[3] = (to + i);
		command[4] = buf[i];
		ret = spi_write(flash->spi, command, 5);
		if (ret < 0)
			goto out;
		copied++;

		/*
		 * Write the remaining bytes using auto address
		 * increment mode
		 */
		bytes = min_t(uint32_t, mtd->writesize, len - i);
		for (j = 1; j < bytes; j++, copied++) {
			ret = sst25l_wait_till_ready(flash);
			if (ret)
				goto out;

			command[1] = buf[i + j];
			ret = spi_write(flash->spi, command, 2);
			if (ret)
				goto out;
		}
	}

out:
	ret = sst25l_write_enable(flash, 0);

	if (retlen)
		*retlen = copied;

	mutex_unlock(&flash->lock);
	return ret;
}

static struct flash_info *__init sst25l_match_device(struct spi_device *spi)
{
	struct flash_info *flash_info = NULL;
	unsigned char command[4], response;
	int i, err;
	uint16_t id;

	command[0] = SST25L_CMD_READ_ID;
	command[1] = 0;
	command[2] = 0;
	command[3] = 0;
	err = spi_write_then_read(spi, command, sizeof(command), &response, 1);
	if (err < 0) {
		dev_err(&spi->dev, "error reading device id msb\n");
		return NULL;
	}

	id = response << 8;

	command[0] = SST25L_CMD_READ_ID;
	command[1] = 0;
	command[2] = 0;
	command[3] = 1;
	err = spi_write_then_read(spi, command, sizeof(command), &response, 1);
	if (err < 0) {
		dev_err(&spi->dev, "error reading device id lsb\n");
		return NULL;
	}

	id |= response;

	for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
		if (sst25l_flash_info[i].device_id == id)
			flash_info = &sst25l_flash_info[i];

	if (!flash_info)
		dev_err(&spi->dev, "unknown id %.4x\n", id);

	return flash_info;
}

static int __init sst25l_probe(struct spi_device *spi)
{
	struct flash_info *flash_info;
	struct sst25l_flash *flash;
	struct flash_platform_data *data;
	int ret, i;

	flash_info = sst25l_match_device(spi);
	if (!flash_info)
		return -ENODEV;

	flash = kzalloc(sizeof(struct sst25l_flash), GFP_KERNEL);
	if (!flash)
		return -ENOMEM;

	flash->spi = spi;
	mutex_init(&flash->lock);
	dev_set_drvdata(&spi->dev, flash);

	data = spi->dev.platform_data;
	if (data && data->name)
		flash->mtd.name = data->name;
	else
		flash->mtd.name = dev_name(&spi->dev);

	flash->mtd.type		= MTD_NORFLASH;
	flash->mtd.flags	= MTD_CAP_NORFLASH;
	flash->mtd.erasesize	= flash_info->erase_size;
	flash->mtd.writesize	= flash_info->page_size;
	flash->mtd.size		= flash_info->page_size * flash_info->nr_pages;
	flash->mtd.erase	= sst25l_erase;
	flash->mtd.read		= sst25l_read;
	flash->mtd.write 	= sst25l_write;

	dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
		 (long long)flash->mtd.size >> 10);

	DEBUG(MTD_DEBUG_LEVEL2,
	      "mtd .name = %s, .size = 0x%llx (%lldMiB) "
	      ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
	      flash->mtd.name,
	      (long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
	      flash->mtd.erasesize, flash->mtd.erasesize / 1024,
	      flash->mtd.numeraseregions);

	if (mtd_has_partitions()) {
		struct mtd_partition *parts = NULL;
		int nr_parts = 0;

		if (mtd_has_cmdlinepart()) {
			static const char *part_probes[] =
				{"cmdlinepart", NULL};

			nr_parts = parse_mtd_partitions(&flash->mtd,
							part_probes,
							&parts, 0);
		}

		if (nr_parts <= 0 && data && data->parts) {
			parts = data->parts;
			nr_parts = data->nr_parts;
		}

		if (nr_parts > 0) {
			for (i = 0; i < nr_parts; i++) {
				DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
				      "{.name = %s, .offset = 0x%llx, "
				      ".size = 0x%llx (%lldKiB) }\n",
				      i, parts[i].name,
				      (long long)parts[i].offset,
				      (long long)parts[i].size,
				      (long long)(parts[i].size >> 10));
			}

			flash->partitioned = 1;
			return add_mtd_partitions(&flash->mtd,
						  parts, nr_parts);
		}

	} else if (data->nr_parts) {
		dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
			 data->nr_parts, data->name);
	}

	ret = add_mtd_device(&flash->mtd);
	if (ret == 1) {
		kfree(flash);
		dev_set_drvdata(&spi->dev, NULL);
		return -ENODEV;
	}

	return 0;
}

static int __exit sst25l_remove(struct spi_device *spi)
{
	struct sst25l_flash *flash = dev_get_drvdata(&spi->dev);
	int ret;

	if (mtd_has_partitions() && flash->partitioned)
		ret = del_mtd_partitions(&flash->mtd);
	else
		ret = del_mtd_device(&flash->mtd);
	if (ret == 0)
		kfree(flash);
	return ret;
}

static struct spi_driver sst25l_driver = {
	.driver = {
		.name	= "sst25l",
		.bus	= &spi_bus_type,
		.owner	= THIS_MODULE,
	},
	.probe		= sst25l_probe,
	.remove		= __exit_p(sst25l_remove),
};

static int __init sst25l_init(void)
{
	return spi_register_driver(&sst25l_driver);
}

static void __exit sst25l_exit(void)
{
	spi_unregister_driver(&sst25l_driver);
}

module_init(sst25l_init);
module_exit(sst25l_exit);

MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
	      "Ryan Mallon <ryan@bluewatersys.com>");
MODULE_LICENSE("GPL");