summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/spi-nor/otp.c
blob: fcf38d26034500e6d3eb7b401d90ce1b74f3fa63 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * OTP support for SPI NOR flashes
 *
 * Copyright (C) 2021 Michael Walle <michael@walle.cc>
 */

#include <linux/log2.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/spi-nor.h>

#include "core.h"

#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
#define spi_nor_otp_n_regions(nor) ((nor)->params->otp.org->n_regions)

/**
 * spi_nor_otp_read_secr() - read OTP data
 * @nor:	pointer to 'struct spi_nor'
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @buf:        pointer to dst buffer
 *
 * Read OTP data from one region by using the SPINOR_OP_RSECR commands. This
 * method is used on GigaDevice and Winbond flashes.
 *
 * Return: number of bytes read successfully, -errno otherwise
 */
int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf)
{
	u8 addr_width, read_opcode, read_dummy;
	struct spi_mem_dirmap_desc *rdesc;
	enum spi_nor_protocol read_proto;
	int ret;

	read_opcode = nor->read_opcode;
	addr_width = nor->addr_width;
	read_dummy = nor->read_dummy;
	read_proto = nor->read_proto;
	rdesc = nor->dirmap.rdesc;

	nor->read_opcode = SPINOR_OP_RSECR;
	nor->addr_width = 3;
	nor->read_dummy = 8;
	nor->read_proto = SNOR_PROTO_1_1_1;
	nor->dirmap.rdesc = NULL;

	ret = spi_nor_read_data(nor, addr, len, buf);

	nor->read_opcode = read_opcode;
	nor->addr_width = addr_width;
	nor->read_dummy = read_dummy;
	nor->read_proto = read_proto;
	nor->dirmap.rdesc = rdesc;

	return ret;
}

/**
 * spi_nor_otp_write_secr() - write OTP data
 * @nor:        pointer to 'struct spi_nor'
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @buf:        pointer to src buffer
 *
 * Write OTP data to one region by using the SPINOR_OP_PSECR commands. This
 * method is used on GigaDevice and Winbond flashes.
 *
 * Please note, the write must not span multiple OTP regions.
 *
 * Return: number of bytes written successfully, -errno otherwise
 */
int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len,
			   const u8 *buf)
{
	enum spi_nor_protocol write_proto;
	struct spi_mem_dirmap_desc *wdesc;
	u8 addr_width, program_opcode;
	int ret, written;

	program_opcode = nor->program_opcode;
	addr_width = nor->addr_width;
	write_proto = nor->write_proto;
	wdesc = nor->dirmap.wdesc;

	nor->program_opcode = SPINOR_OP_PSECR;
	nor->addr_width = 3;
	nor->write_proto = SNOR_PROTO_1_1_1;
	nor->dirmap.wdesc = NULL;

	/*
	 * We only support a write to one single page. For now all winbond
	 * flashes only have one page per OTP region.
	 */
	ret = spi_nor_write_enable(nor);
	if (ret)
		goto out;

	written = spi_nor_write_data(nor, addr, len, buf);
	if (written < 0)
		goto out;

	ret = spi_nor_wait_till_ready(nor);

out:
	nor->program_opcode = program_opcode;
	nor->addr_width = addr_width;
	nor->write_proto = write_proto;
	nor->dirmap.wdesc = wdesc;

	return ret ?: written;
}

static int spi_nor_otp_lock_bit_cr(unsigned int region)
{
	static const int lock_bits[] = { SR2_LB1, SR2_LB2, SR2_LB3 };

	if (region >= ARRAY_SIZE(lock_bits))
		return -EINVAL;

	return lock_bits[region];
}

/**
 * spi_nor_otp_lock_sr2() - lock the OTP region
 * @nor:        pointer to 'struct spi_nor'
 * @region:     OTP region
 *
 * Lock the OTP region by writing the status register-2. This method is used on
 * GigaDevice and Winbond flashes.
 *
 * Return: 0 on success, -errno otherwise.
 */
int spi_nor_otp_lock_sr2(struct spi_nor *nor, unsigned int region)
{
	u8 *cr = nor->bouncebuf;
	int ret, lock_bit;

	lock_bit = spi_nor_otp_lock_bit_cr(region);
	if (lock_bit < 0)
		return lock_bit;

	ret = spi_nor_read_cr(nor, cr);
	if (ret)
		return ret;

	/* no need to write the register if region is already locked */
	if (cr[0] & lock_bit)
		return 0;

	cr[0] |= lock_bit;

	return spi_nor_write_16bit_cr_and_check(nor, cr[0]);
}

/**
 * spi_nor_otp_is_locked_sr2() - get the OTP region lock status
 * @nor:        pointer to 'struct spi_nor'
 * @region:     OTP region
 *
 * Retrieve the OTP region lock bit by reading the status register-2. This
 * method is used on GigaDevice and Winbond flashes.
 *
 * Return: 0 on success, -errno otherwise.
 */
int spi_nor_otp_is_locked_sr2(struct spi_nor *nor, unsigned int region)
{
	u8 *cr = nor->bouncebuf;
	int ret, lock_bit;

	lock_bit = spi_nor_otp_lock_bit_cr(region);
	if (lock_bit < 0)
		return lock_bit;

	ret = spi_nor_read_cr(nor, cr);
	if (ret)
		return ret;

	return cr[0] & lock_bit;
}

static loff_t spi_nor_otp_region_start(const struct spi_nor *nor, unsigned int region)
{
	const struct spi_nor_otp_organization *org = nor->params->otp.org;

	return org->base + region * org->offset;
}

static size_t spi_nor_otp_size(struct spi_nor *nor)
{
	return spi_nor_otp_n_regions(nor) * spi_nor_otp_region_len(nor);
}

/* Translate the file offsets from and to OTP regions. */
static loff_t spi_nor_otp_region_to_offset(struct spi_nor *nor, unsigned int region)
{
	return region * spi_nor_otp_region_len(nor);
}

static unsigned int spi_nor_otp_offset_to_region(struct spi_nor *nor, loff_t ofs)
{
	return div64_u64(ofs, spi_nor_otp_region_len(nor));
}

static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len,
				size_t *retlen, struct otp_info *buf)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	const struct spi_nor_otp_ops *ops = nor->params->otp.ops;
	unsigned int n_regions = spi_nor_otp_n_regions(nor);
	unsigned int i;
	int ret, locked;

	if (len < n_regions * sizeof(*buf))
		return -ENOSPC;

	ret = spi_nor_lock_and_prep(nor);
	if (ret)
		return ret;

	for (i = 0; i < n_regions; i++) {
		buf->start = spi_nor_otp_region_to_offset(nor, i);
		buf->length = spi_nor_otp_region_len(nor);

		locked = ops->is_locked(nor, i);
		if (locked < 0) {
			ret = locked;
			goto out;
		}

		buf->locked = !!locked;
		buf++;
	}

	*retlen = n_regions * sizeof(*buf);

out:
	spi_nor_unlock_and_unprep(nor);

	return ret;
}

static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs,
				      size_t total_len, size_t *retlen,
				      const u8 *buf, bool is_write)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	const struct spi_nor_otp_ops *ops = nor->params->otp.ops;
	const size_t rlen = spi_nor_otp_region_len(nor);
	loff_t rstart, rofs;
	unsigned int region;
	size_t len;
	int ret;

	if (ofs < 0 || ofs >= spi_nor_otp_size(nor))
		return 0;

	ret = spi_nor_lock_and_prep(nor);
	if (ret)
		return ret;

	/* don't access beyond the end */
	total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs);

	*retlen = 0;
	while (total_len) {
		/*
		 * The OTP regions are mapped into a contiguous area starting
		 * at 0 as expected by the MTD layer. This will map the MTD
		 * file offsets to the address of an OTP region as used in the
		 * actual SPI commands.
		 */
		region = spi_nor_otp_offset_to_region(nor, ofs);
		rstart = spi_nor_otp_region_start(nor, region);

		/*
		 * The size of a OTP region is expected to be a power of two,
		 * thus we can just mask the lower bits and get the offset into
		 * a region.
		 */
		rofs = ofs & (rlen - 1);

		/* don't access beyond one OTP region */
		len = min_t(size_t, total_len, rlen - rofs);

		if (is_write)
			ret = ops->write(nor, rstart + rofs, len, buf);
		else
			ret = ops->read(nor, rstart + rofs, len, (u8 *)buf);
		if (ret == 0)
			ret = -EIO;
		if (ret < 0)
			goto out;

		*retlen += ret;
		ofs += ret;
		buf += ret;
		total_len -= ret;
	}
	ret = 0;

out:
	spi_nor_unlock_and_unprep(nor);
	return ret;
}

static int spi_nor_mtd_otp_read(struct mtd_info *mtd, loff_t from, size_t len,
				size_t *retlen, u8 *buf)
{
	return spi_nor_mtd_otp_read_write(mtd, from, len, retlen, buf, false);
}

static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
				 size_t *retlen, const u8 *buf)
{
	return spi_nor_mtd_otp_read_write(mtd, to, len, retlen, buf, true);
}

static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	const struct spi_nor_otp_ops *ops = nor->params->otp.ops;
	const size_t rlen = spi_nor_otp_region_len(nor);
	unsigned int region;
	int ret;

	if (from < 0 || (from + len) > spi_nor_otp_size(nor))
		return -EINVAL;

	/* the user has to explicitly ask for whole regions */
	if (!IS_ALIGNED(len, rlen) || !IS_ALIGNED(from, rlen))
		return -EINVAL;

	ret = spi_nor_lock_and_prep(nor);
	if (ret)
		return ret;

	while (len) {
		region = spi_nor_otp_offset_to_region(nor, from);
		ret = ops->lock(nor, region);
		if (ret)
			goto out;

		len -= rlen;
		from += rlen;
	}

out:
	spi_nor_unlock_and_unprep(nor);

	return ret;
}

void spi_nor_otp_init(struct spi_nor *nor)
{
	struct mtd_info *mtd = &nor->mtd;

	if (!nor->params->otp.ops)
		return;

	if (WARN_ON(!is_power_of_2(spi_nor_otp_region_len(nor))))
		return;

	/*
	 * We only support user_prot callbacks (yet).
	 *
	 * Some SPI NOR flashes like Macronix ones can be ordered in two
	 * different variants. One with a factory locked OTP area and one where
	 * it is left to the user to write to it. The factory locked OTP is
	 * usually preprogrammed with an "electrical serial number". We don't
	 * support these for now.
	 */
	mtd->_get_user_prot_info = spi_nor_mtd_otp_info;
	mtd->_read_user_prot_reg = spi_nor_mtd_otp_read;
	mtd->_write_user_prot_reg = spi_nor_mtd_otp_write;
	mtd->_lock_user_prot_reg = spi_nor_mtd_otp_lock;
}