aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/nvmem/imx-ocotp.c
blob: d94ed2d69a10ca0e30276de1acaf97e63d73062c (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
/*
 * i.MX6 OCOTP fusebox driver
 *
 * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
 *
 * Based on the barebox ocotp driver,
 * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
 *	Orex Computed Radiography
 *
 * Write support based on the fsl_otp driver,
 * Copyright (C) 2010-2013 Freescale Semiconductor, Inc
 *
 * 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.
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/delay.h>

#define IMX_OCOTP_OFFSET_B0W0		0x400 /* Offset from base address of the
					       * OTP Bank0 Word0
					       */
#define IMX_OCOTP_OFFSET_PER_WORD	0x10  /* Offset between the start addr
					       * of two consecutive OTP words.
					       */

#define IMX_OCOTP_ADDR_CTRL		0x0000
#define IMX_OCOTP_ADDR_CTRL_SET		0x0004
#define IMX_OCOTP_ADDR_CTRL_CLR		0x0008
#define IMX_OCOTP_ADDR_TIMING		0x0010
#define IMX_OCOTP_ADDR_DATA		0x0020

#define IMX_OCOTP_BM_CTRL_ADDR		0x0000007F
#define IMX_OCOTP_BM_CTRL_BUSY		0x00000100
#define IMX_OCOTP_BM_CTRL_ERROR		0x00000200
#define IMX_OCOTP_BM_CTRL_REL_SHADOWS	0x00000400

#define DEF_RELAX			20 /* > 16.5ns */
#define IMX_OCOTP_WR_UNLOCK		0x3E770000
#define IMX_OCOTP_READ_LOCKED_VAL	0xBADABADA

static DEFINE_MUTEX(ocotp_mutex);

struct ocotp_params {
	unsigned int nregs;
};

struct ocotp_priv {
	struct device *dev;
	struct clk *clk;
	void __iomem *base;
	const struct ocotp_params *params;
	struct nvmem_config *config;
};

static int imx_ocotp_wait_for_busy(void __iomem *base, u32 flags)
{
	int count;
	u32 c, mask;

	mask = IMX_OCOTP_BM_CTRL_BUSY | IMX_OCOTP_BM_CTRL_ERROR | flags;

	for (count = 10000; count >= 0; count--) {
		c = readl(base + IMX_OCOTP_ADDR_CTRL);
		if (!(c & mask))
			break;
		cpu_relax();
	}

	if (count < 0) {
		/* HW_OCOTP_CTRL[ERROR] will be set under the following
		 * conditions:
		 * - A write is performed to a shadow register during a shadow
		 *   reload (essentially, while HW_OCOTP_CTRL[RELOAD_SHADOWS] is
		 *   set. In addition, the contents of the shadow register shall
		 *   not be updated.
		 * - A write is performed to a shadow register which has been
		 *   locked.
		 * - A read is performed to from a shadow register which has
		 *   been read locked.
		 * - A program is performed to a fuse word which has been locked
		 * - A read is performed to from a fuse word which has been read
		 *   locked.
		 */
		if (c & IMX_OCOTP_BM_CTRL_ERROR)
			return -EPERM;
		return -ETIMEDOUT;
	}

	return 0;
}

static void imx_ocotp_clr_err_if_set(void __iomem *base)
{
	u32 c;

	c = readl(base + IMX_OCOTP_ADDR_CTRL);
	if (!(c & IMX_OCOTP_BM_CTRL_ERROR))
		return;

	writel(IMX_OCOTP_BM_CTRL_ERROR, base + IMX_OCOTP_ADDR_CTRL_CLR);
}

static int imx_ocotp_read(void *context, unsigned int offset,
			  void *val, size_t bytes)
{
	struct ocotp_priv *priv = context;
	unsigned int count;
	u32 *buf = val;
	int i, ret;
	u32 index;

	index = offset >> 2;
	count = bytes >> 2;

	if (count > (priv->params->nregs - index))
		count = priv->params->nregs - index;

	mutex_lock(&ocotp_mutex);

	ret = clk_prepare_enable(priv->clk);
	if (ret < 0) {
		mutex_unlock(&ocotp_mutex);
		dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
		return ret;
	}

	ret = imx_ocotp_wait_for_busy(priv->base, 0);
	if (ret < 0) {
		dev_err(priv->dev, "timeout during read setup\n");
		goto read_end;
	}

	for (i = index; i < (index + count); i++) {
		*buf++ = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 +
			       i * IMX_OCOTP_OFFSET_PER_WORD);

		/* 47.3.1.2
		 * For "read locked" registers 0xBADABADA will be returned and
		 * HW_OCOTP_CTRL[ERROR] will be set. It must be cleared by
		 * software before any new write, read or reload access can be
		 * issued
		 */
		if (*(buf - 1) == IMX_OCOTP_READ_LOCKED_VAL)
			imx_ocotp_clr_err_if_set(priv->base);
	}
	ret = 0;

read_end:
	clk_disable_unprepare(priv->clk);
	mutex_unlock(&ocotp_mutex);
	return ret;
}

static int imx_ocotp_write(void *context, unsigned int offset, void *val,
			   size_t bytes)
{
	struct ocotp_priv *priv = context;
	u32 *buf = val;
	int ret;

	unsigned long clk_rate = 0;
	unsigned long strobe_read, relax, strobe_prog;
	u32 timing = 0;
	u32 ctrl;
	u8 waddr;

	/* allow only writing one complete OTP word at a time */
	if ((bytes != priv->config->word_size) ||
	    (offset % priv->config->word_size))
		return -EINVAL;

	mutex_lock(&ocotp_mutex);

	ret = clk_prepare_enable(priv->clk);
	if (ret < 0) {
		mutex_unlock(&ocotp_mutex);
		dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
		return ret;
	}

	/* 47.3.1.3.1
	 * Program HW_OCOTP_TIMING[STROBE_PROG] and HW_OCOTP_TIMING[RELAX]
	 * fields with timing values to match the current frequency of the
	 * ipg_clk. OTP writes will work at maximum bus frequencies as long
	 * as the HW_OCOTP_TIMING parameters are set correctly.
	 */
	clk_rate = clk_get_rate(priv->clk);

	relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
	strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
	strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;

	timing = strobe_prog & 0x00000FFF;
	timing |= (relax       << 12) & 0x0000F000;
	timing |= (strobe_read << 16) & 0x003F0000;

	writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);

	/* 47.3.1.3.2
	 * Check that HW_OCOTP_CTRL[BUSY] and HW_OCOTP_CTRL[ERROR] are clear.
	 * Overlapped accesses are not supported by the controller. Any pending
	 * write or reload must be completed before a write access can be
	 * requested.
	 */
	ret = imx_ocotp_wait_for_busy(priv->base, 0);
	if (ret < 0) {
		dev_err(priv->dev, "timeout during timing setup\n");
		goto write_end;
	}

	/* 47.3.1.3.3
	 * Write the requested address to HW_OCOTP_CTRL[ADDR] and program the
	 * unlock code into HW_OCOTP_CTRL[WR_UNLOCK]. This must be programmed
	 * for each write access. The lock code is documented in the register
	 * description. Both the unlock code and address can be written in the
	 * same operation.
	 */
	/* OTP write/read address specifies one of 128 word address locations */
	waddr = offset / 4;

	ctrl = readl(priv->base + IMX_OCOTP_ADDR_CTRL);
	ctrl &= ~IMX_OCOTP_BM_CTRL_ADDR;
	ctrl |= waddr & IMX_OCOTP_BM_CTRL_ADDR;
	ctrl |= IMX_OCOTP_WR_UNLOCK;

	writel(ctrl, priv->base + IMX_OCOTP_ADDR_CTRL);

	/* 47.3.1.3.4
	 * Write the data to the HW_OCOTP_DATA register. This will automatically
	 * set HW_OCOTP_CTRL[BUSY] and clear HW_OCOTP_CTRL[WR_UNLOCK]. To
	 * protect programming same OTP bit twice, before program OCOTP will
	 * automatically read fuse value in OTP and use read value to mask
	 * program data. The controller will use masked program data to program
	 * a 32-bit word in the OTP per the address in HW_OCOTP_CTRL[ADDR]. Bit
	 * fields with 1's will result in that OTP bit being programmed. Bit
	 * fields with 0's will be ignored. At the same time that the write is
	 * accepted, the controller makes an internal copy of
	 * HW_OCOTP_CTRL[ADDR] which cannot be updated until the next write
	 * sequence is initiated. This copy guarantees that erroneous writes to
	 * HW_OCOTP_CTRL[ADDR] will not affect an active write operation. It
	 * should also be noted that during the programming HW_OCOTP_DATA will
	 * shift right (with zero fill). This shifting is required to program
	 * the OTP serially. During the write operation, HW_OCOTP_DATA cannot be
	 * modified.
	 */
	writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA);

	/* 47.4.1.4.5
	 * Once complete, the controller will clear BUSY. A write request to a
	 * protected or locked region will result in no OTP access and no
	 * setting of HW_OCOTP_CTRL[BUSY]. In addition HW_OCOTP_CTRL[ERROR] will
	 * be set. It must be cleared by software before any new write access
	 * can be issued.
	 */
	ret = imx_ocotp_wait_for_busy(priv->base, 0);
	if (ret < 0) {
		if (ret == -EPERM) {
			dev_err(priv->dev, "failed write to locked region");
			imx_ocotp_clr_err_if_set(priv->base);
		} else {
			dev_err(priv->dev, "timeout during data write\n");
		}
		goto write_end;
	}

	/* 47.3.1.4
	 * Write Postamble: Due to internal electrical characteristics of the
	 * OTP during writes, all OTP operations following a write must be
	 * separated by 2 us after the clearing of HW_OCOTP_CTRL_BUSY following
	 * the write.
	 */
	udelay(2);

	/* reload all shadow registers */
	writel(IMX_OCOTP_BM_CTRL_REL_SHADOWS,
	       priv->base + IMX_OCOTP_ADDR_CTRL_SET);
	ret = imx_ocotp_wait_for_busy(priv->base,
				      IMX_OCOTP_BM_CTRL_REL_SHADOWS);
	if (ret < 0) {
		dev_err(priv->dev, "timeout during shadow register reload\n");
		goto write_end;
	}

write_end:
	clk_disable_unprepare(priv->clk);
	mutex_unlock(&ocotp_mutex);
	if (ret < 0)
		return ret;
	return bytes;
}

static struct nvmem_config imx_ocotp_nvmem_config = {
	.name = "imx-ocotp",
	.read_only = false,
	.word_size = 4,
	.stride = 4,
	.reg_read = imx_ocotp_read,
	.reg_write = imx_ocotp_write,
};

static const struct ocotp_params imx6q_params = {
	.nregs = 128,
};

static const struct ocotp_params imx6sl_params = {
	.nregs = 64,
};

static const struct ocotp_params imx6sx_params = {
	.nregs = 128,
};

static const struct ocotp_params imx6ul_params = {
	.nregs = 128,
};

static const struct ocotp_params imx7d_params = {
	.nregs = 64,
};

static const struct of_device_id imx_ocotp_dt_ids[] = {
	{ .compatible = "fsl,imx6q-ocotp",  .data = &imx6q_params },
	{ .compatible = "fsl,imx6sl-ocotp", .data = &imx6sl_params },
	{ .compatible = "fsl,imx6sx-ocotp", .data = &imx6sx_params },
	{ .compatible = "fsl,imx6ul-ocotp", .data = &imx6ul_params },
	{ .compatible = "fsl,imx7d-ocotp",  .data = &imx7d_params },
	{ },
};
MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);

static int imx_ocotp_probe(struct platform_device *pdev)
{
	const struct of_device_id *of_id;
	struct device *dev = &pdev->dev;
	struct resource *res;
	struct ocotp_priv *priv;
	struct nvmem_device *nvmem;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->dev = dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	priv->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(priv->base))
		return PTR_ERR(priv->base);

	priv->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(priv->clk))
		return PTR_ERR(priv->clk);

	of_id = of_match_device(imx_ocotp_dt_ids, dev);
	priv->params = of_device_get_match_data(&pdev->dev);
	imx_ocotp_nvmem_config.size = 4 * priv->params->nregs;
	imx_ocotp_nvmem_config.dev = dev;
	imx_ocotp_nvmem_config.priv = priv;
	priv->config = &imx_ocotp_nvmem_config;
	if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx7d-ocotp"))
		imx_ocotp_nvmem_config.read_only = true;
	nvmem = nvmem_register(&imx_ocotp_nvmem_config);

	if (IS_ERR(nvmem))
		return PTR_ERR(nvmem);

	platform_set_drvdata(pdev, nvmem);

	return 0;
}

static int imx_ocotp_remove(struct platform_device *pdev)
{
	struct nvmem_device *nvmem = platform_get_drvdata(pdev);

	return nvmem_unregister(nvmem);
}

static struct platform_driver imx_ocotp_driver = {
	.probe	= imx_ocotp_probe,
	.remove	= imx_ocotp_remove,
	.driver = {
		.name	= "imx_ocotp",
		.of_match_table = imx_ocotp_dt_ids,
	},
};
module_platform_driver(imx_ocotp_driver);

MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver");
MODULE_LICENSE("GPL v2");

Privacy Policy