1 // SPDX-License-Identifier: GPL-2.0-only
3 * i.MX6 OCOTP fusebox driver
5 * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
9 * Based on the barebox ocotp driver,
10 * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
11 * Orex Computed Radiography
13 * Write support based on the fsl_otp driver,
14 * Copyright (C) 2010-2013 Freescale Semiconductor, Inc
17 #include <linux/clk.h>
18 #include <linux/device.h>
20 #include <linux/module.h>
21 #include <linux/nvmem-provider.h>
23 #include <linux/of_device.h>
24 #include <linux/platform_device.h>
25 #include <linux/slab.h>
26 #include <linux/delay.h>
28 #define IMX_OCOTP_OFFSET_B0W0 0x400 /* Offset from base address of the
31 #define IMX_OCOTP_OFFSET_PER_WORD 0x10 /* Offset between the start addr
32 * of two consecutive OTP words.
35 #define IMX_OCOTP_ADDR_CTRL 0x0000
36 #define IMX_OCOTP_ADDR_CTRL_SET 0x0004
37 #define IMX_OCOTP_ADDR_CTRL_CLR 0x0008
38 #define IMX_OCOTP_ADDR_TIMING 0x0010
39 #define IMX_OCOTP_ADDR_DATA0 0x0020
40 #define IMX_OCOTP_ADDR_DATA1 0x0030
41 #define IMX_OCOTP_ADDR_DATA2 0x0040
42 #define IMX_OCOTP_ADDR_DATA3 0x0050
44 #define IMX_OCOTP_BM_CTRL_ADDR 0x000000FF
45 #define IMX_OCOTP_BM_CTRL_BUSY 0x00000100
46 #define IMX_OCOTP_BM_CTRL_ERROR 0x00000200
47 #define IMX_OCOTP_BM_CTRL_REL_SHADOWS 0x00000400
49 #define IMX_OCOTP_BM_CTRL_ADDR_8MP 0x000001FF
50 #define IMX_OCOTP_BM_CTRL_BUSY_8MP 0x00000200
51 #define IMX_OCOTP_BM_CTRL_ERROR_8MP 0x00000400
52 #define IMX_OCOTP_BM_CTRL_REL_SHADOWS_8MP 0x00000800
54 #define IMX_OCOTP_BM_CTRL_DEFAULT \
56 .bm_addr = IMX_OCOTP_BM_CTRL_ADDR, \
57 .bm_busy = IMX_OCOTP_BM_CTRL_BUSY, \
58 .bm_error = IMX_OCOTP_BM_CTRL_ERROR, \
59 .bm_rel_shadows = IMX_OCOTP_BM_CTRL_REL_SHADOWS,\
62 #define IMX_OCOTP_BM_CTRL_8MP \
64 .bm_addr = IMX_OCOTP_BM_CTRL_ADDR_8MP, \
65 .bm_busy = IMX_OCOTP_BM_CTRL_BUSY_8MP, \
66 .bm_error = IMX_OCOTP_BM_CTRL_ERROR_8MP, \
67 .bm_rel_shadows = IMX_OCOTP_BM_CTRL_REL_SHADOWS_8MP,\
70 #define TIMING_STROBE_PROG_US 10 /* Min time to blow a fuse */
71 #define TIMING_STROBE_READ_NS 37 /* Min time before read */
72 #define TIMING_RELAX_NS 17
73 #define DEF_FSOURCE 1001 /* > 1000 ns */
74 #define DEF_STROBE_PROG 10000 /* IPG clocks */
75 #define IMX_OCOTP_WR_UNLOCK 0x3E770000
76 #define IMX_OCOTP_READ_LOCKED_VAL 0xBADABADA
78 static DEFINE_MUTEX(ocotp_mutex);
84 const struct ocotp_params *params;
85 struct nvmem_config *config;
88 struct ocotp_ctrl_reg {
97 unsigned int bank_address_words;
98 void (*set_timing)(struct ocotp_priv *priv);
99 struct ocotp_ctrl_reg ctrl;
102 static int imx_ocotp_wait_for_busy(struct ocotp_priv *priv, u32 flags)
106 u32 bm_ctrl_busy, bm_ctrl_error;
107 void __iomem *base = priv->base;
109 bm_ctrl_busy = priv->params->ctrl.bm_busy;
110 bm_ctrl_error = priv->params->ctrl.bm_error;
112 mask = bm_ctrl_busy | bm_ctrl_error | flags;
114 for (count = 10000; count >= 0; count--) {
115 c = readl(base + IMX_OCOTP_ADDR_CTRL);
122 /* HW_OCOTP_CTRL[ERROR] will be set under the following
124 * - A write is performed to a shadow register during a shadow
125 * reload (essentially, while HW_OCOTP_CTRL[RELOAD_SHADOWS] is
126 * set. In addition, the contents of the shadow register shall
128 * - A write is performed to a shadow register which has been
130 * - A read is performed to from a shadow register which has
132 * - A program is performed to a fuse word which has been locked
133 * - A read is performed to from a fuse word which has been read
136 if (c & bm_ctrl_error)
144 static void imx_ocotp_clr_err_if_set(struct ocotp_priv *priv)
146 u32 c, bm_ctrl_error;
147 void __iomem *base = priv->base;
149 bm_ctrl_error = priv->params->ctrl.bm_error;
151 c = readl(base + IMX_OCOTP_ADDR_CTRL);
152 if (!(c & bm_ctrl_error))
155 writel(bm_ctrl_error, base + IMX_OCOTP_ADDR_CTRL_CLR);
158 static int imx_ocotp_read(void *context, unsigned int offset,
159 void *val, size_t bytes)
161 struct ocotp_priv *priv = context;
165 u32 index, num_bytes;
168 num_bytes = round_up((offset % 4) + bytes, 4);
169 count = num_bytes >> 2;
171 if (count > (priv->params->nregs - index))
172 count = priv->params->nregs - index;
174 p = kzalloc(num_bytes, GFP_KERNEL);
178 mutex_lock(&ocotp_mutex);
182 ret = clk_prepare_enable(priv->clk);
184 mutex_unlock(&ocotp_mutex);
185 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
190 ret = imx_ocotp_wait_for_busy(priv, 0);
192 dev_err(priv->dev, "timeout during read setup\n");
196 for (i = index; i < (index + count); i++) {
197 *(u32 *)buf = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 +
198 i * IMX_OCOTP_OFFSET_PER_WORD);
201 * For "read locked" registers 0xBADABADA will be returned and
202 * HW_OCOTP_CTRL[ERROR] will be set. It must be cleared by
203 * software before any new write, read or reload access can be
206 if (*((u32 *)buf) == IMX_OCOTP_READ_LOCKED_VAL)
207 imx_ocotp_clr_err_if_set(priv);
213 memcpy(val, &p[index], bytes);
216 clk_disable_unprepare(priv->clk);
217 mutex_unlock(&ocotp_mutex);
224 static void imx_ocotp_set_imx6_timing(struct ocotp_priv *priv)
226 unsigned long clk_rate;
227 unsigned long strobe_read, relax, strobe_prog;
231 * Program HW_OCOTP_TIMING[STROBE_PROG] and HW_OCOTP_TIMING[RELAX]
232 * fields with timing values to match the current frequency of the
233 * ipg_clk. OTP writes will work at maximum bus frequencies as long
234 * as the HW_OCOTP_TIMING parameters are set correctly.
236 * Note: there are minimum timings required to ensure an OTP fuse burns
237 * correctly that are independent of the ipg_clk. Those values are not
238 * formally documented anywhere however, working from the minimum
239 * timings given in u-boot we can say:
241 * - Minimum STROBE_PROG time is 10 microseconds. Intuitively 10
242 * microseconds feels about right as representative of a minimum time
243 * to physically burn out a fuse.
245 * - Minimum STROBE_READ i.e. the time to wait post OTP fuse burn before
246 * performing another read is 37 nanoseconds
248 * - Minimum RELAX timing is 17 nanoseconds. This final RELAX minimum
249 * timing is not entirely clear the documentation says "This
250 * count value specifies the time to add to all default timing
251 * parameters other than the Tpgm and Trd. It is given in number
252 * of ipg_clk periods." where Tpgm and Trd refer to STROBE_PROG
253 * and STROBE_READ respectively. What the other timing parameters
254 * are though, is not specified. Experience shows a zero RELAX
255 * value will mess up a re-load of the shadow registers post OTP
258 clk_rate = clk_get_rate(priv->clk);
260 relax = DIV_ROUND_UP(clk_rate * TIMING_RELAX_NS, 1000000000) - 1;
261 strobe_read = DIV_ROUND_UP(clk_rate * TIMING_STROBE_READ_NS,
263 strobe_read += 2 * (relax + 1) - 1;
264 strobe_prog = DIV_ROUND_CLOSEST(clk_rate * TIMING_STROBE_PROG_US,
266 strobe_prog += 2 * (relax + 1) - 1;
268 timing = readl(priv->base + IMX_OCOTP_ADDR_TIMING) & 0x0FC00000;
269 timing |= strobe_prog & 0x00000FFF;
270 timing |= (relax << 12) & 0x0000F000;
271 timing |= (strobe_read << 16) & 0x003F0000;
273 writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
276 static void imx_ocotp_set_imx7_timing(struct ocotp_priv *priv)
278 unsigned long clk_rate;
279 u64 fsource, strobe_prog;
282 /* i.MX 7Solo Applications Processor Reference Manual, Rev. 0.1
285 clk_rate = clk_get_rate(priv->clk);
286 fsource = DIV_ROUND_UP_ULL((u64)clk_rate * DEF_FSOURCE,
288 strobe_prog = DIV_ROUND_CLOSEST_ULL((u64)clk_rate * DEF_STROBE_PROG,
291 timing = strobe_prog & 0x00000FFF;
292 timing |= (fsource << 12) & 0x000FF000;
294 writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
297 static int imx_ocotp_write(void *context, unsigned int offset, void *val,
300 struct ocotp_priv *priv = context;
308 /* allow only writing one complete OTP word at a time */
309 if ((bytes != priv->config->word_size) ||
310 (offset % priv->config->word_size))
313 mutex_lock(&ocotp_mutex);
315 ret = clk_prepare_enable(priv->clk);
317 mutex_unlock(&ocotp_mutex);
318 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
322 /* Setup the write timing values */
323 priv->params->set_timing(priv);
326 * Check that HW_OCOTP_CTRL[BUSY] and HW_OCOTP_CTRL[ERROR] are clear.
327 * Overlapped accesses are not supported by the controller. Any pending
328 * write or reload must be completed before a write access can be
331 ret = imx_ocotp_wait_for_busy(priv, 0);
333 dev_err(priv->dev, "timeout during timing setup\n");
338 * Write the requested address to HW_OCOTP_CTRL[ADDR] and program the
339 * unlock code into HW_OCOTP_CTRL[WR_UNLOCK]. This must be programmed
340 * for each write access. The lock code is documented in the register
341 * description. Both the unlock code and address can be written in the
344 if (priv->params->bank_address_words != 0) {
346 * In banked/i.MX7 mode the OTP register bank goes into waddr
347 * see i.MX 7Solo Applications Processor Reference Manual, Rev.
348 * 0.1 section 6.4.3.1
350 offset = offset / priv->config->word_size;
351 waddr = offset / priv->params->bank_address_words;
352 word = offset & (priv->params->bank_address_words - 1);
355 * Non-banked i.MX6 mode.
356 * OTP write/read address specifies one of 128 word address
362 ctrl = readl(priv->base + IMX_OCOTP_ADDR_CTRL);
363 ctrl &= ~priv->params->ctrl.bm_addr;
364 ctrl |= waddr & priv->params->ctrl.bm_addr;
365 ctrl |= IMX_OCOTP_WR_UNLOCK;
367 writel(ctrl, priv->base + IMX_OCOTP_ADDR_CTRL);
370 * Write the data to the HW_OCOTP_DATA register. This will automatically
371 * set HW_OCOTP_CTRL[BUSY] and clear HW_OCOTP_CTRL[WR_UNLOCK]. To
372 * protect programming same OTP bit twice, before program OCOTP will
373 * automatically read fuse value in OTP and use read value to mask
374 * program data. The controller will use masked program data to program
375 * a 32-bit word in the OTP per the address in HW_OCOTP_CTRL[ADDR]. Bit
376 * fields with 1's will result in that OTP bit being programmed. Bit
377 * fields with 0's will be ignored. At the same time that the write is
378 * accepted, the controller makes an internal copy of
379 * HW_OCOTP_CTRL[ADDR] which cannot be updated until the next write
380 * sequence is initiated. This copy guarantees that erroneous writes to
381 * HW_OCOTP_CTRL[ADDR] will not affect an active write operation. It
382 * should also be noted that during the programming HW_OCOTP_DATA will
383 * shift right (with zero fill). This shifting is required to program
384 * the OTP serially. During the write operation, HW_OCOTP_DATA cannot be
386 * Note: on i.MX7 there are four data fields to write for banked write
387 * with the fuse blowing operation only taking place after data0
388 * has been written. This is why data0 must always be the last
391 if (priv->params->bank_address_words != 0) {
392 /* Banked/i.MX7 mode */
395 writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
396 writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
397 writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
398 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA0);
401 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA1);
402 writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
403 writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
404 writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
407 writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
408 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA2);
409 writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
410 writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
413 writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
414 writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
415 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA3);
416 writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
420 /* Non-banked i.MX6 mode */
421 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA0);
425 * Once complete, the controller will clear BUSY. A write request to a
426 * protected or locked region will result in no OTP access and no
427 * setting of HW_OCOTP_CTRL[BUSY]. In addition HW_OCOTP_CTRL[ERROR] will
428 * be set. It must be cleared by software before any new write access
431 ret = imx_ocotp_wait_for_busy(priv, 0);
434 dev_err(priv->dev, "failed write to locked region");
435 imx_ocotp_clr_err_if_set(priv);
437 dev_err(priv->dev, "timeout during data write\n");
443 * Write Postamble: Due to internal electrical characteristics of the
444 * OTP during writes, all OTP operations following a write must be
445 * separated by 2 us after the clearing of HW_OCOTP_CTRL_BUSY following
450 /* reload all shadow registers */
451 writel(priv->params->ctrl.bm_rel_shadows,
452 priv->base + IMX_OCOTP_ADDR_CTRL_SET);
453 ret = imx_ocotp_wait_for_busy(priv,
454 priv->params->ctrl.bm_rel_shadows);
456 dev_err(priv->dev, "timeout during shadow register reload\n");
459 clk_disable_unprepare(priv->clk);
460 mutex_unlock(&ocotp_mutex);
461 return ret < 0 ? ret : bytes;
464 static struct nvmem_config imx_ocotp_nvmem_config = {
469 .reg_read = imx_ocotp_read,
470 .reg_write = imx_ocotp_write,
473 static const struct ocotp_params imx6q_params = {
475 .bank_address_words = 0,
476 .set_timing = imx_ocotp_set_imx6_timing,
477 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
480 static const struct ocotp_params imx6sl_params = {
482 .bank_address_words = 0,
483 .set_timing = imx_ocotp_set_imx6_timing,
484 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
487 static const struct ocotp_params imx6sll_params = {
489 .bank_address_words = 0,
490 .set_timing = imx_ocotp_set_imx6_timing,
491 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
494 static const struct ocotp_params imx6sx_params = {
496 .bank_address_words = 0,
497 .set_timing = imx_ocotp_set_imx6_timing,
498 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
501 static const struct ocotp_params imx6ul_params = {
503 .bank_address_words = 0,
504 .set_timing = imx_ocotp_set_imx6_timing,
505 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
508 static const struct ocotp_params imx6ull_params = {
510 .bank_address_words = 0,
511 .set_timing = imx_ocotp_set_imx6_timing,
512 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
515 static const struct ocotp_params imx7d_params = {
517 .bank_address_words = 4,
518 .set_timing = imx_ocotp_set_imx7_timing,
519 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
522 static const struct ocotp_params imx7ulp_params = {
524 .bank_address_words = 0,
525 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
528 static const struct ocotp_params imx8mq_params = {
530 .bank_address_words = 0,
531 .set_timing = imx_ocotp_set_imx6_timing,
532 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
535 static const struct ocotp_params imx8mm_params = {
537 .bank_address_words = 0,
538 .set_timing = imx_ocotp_set_imx6_timing,
539 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
542 static const struct ocotp_params imx8mn_params = {
544 .bank_address_words = 0,
545 .set_timing = imx_ocotp_set_imx6_timing,
546 .ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
549 static const struct ocotp_params imx8mp_params = {
551 .bank_address_words = 0,
552 .set_timing = imx_ocotp_set_imx6_timing,
553 .ctrl = IMX_OCOTP_BM_CTRL_8MP,
556 static const struct of_device_id imx_ocotp_dt_ids[] = {
557 { .compatible = "fsl,imx6q-ocotp", .data = &imx6q_params },
558 { .compatible = "fsl,imx6sl-ocotp", .data = &imx6sl_params },
559 { .compatible = "fsl,imx6sx-ocotp", .data = &imx6sx_params },
560 { .compatible = "fsl,imx6ul-ocotp", .data = &imx6ul_params },
561 { .compatible = "fsl,imx6ull-ocotp", .data = &imx6ull_params },
562 { .compatible = "fsl,imx7d-ocotp", .data = &imx7d_params },
563 { .compatible = "fsl,imx6sll-ocotp", .data = &imx6sll_params },
564 { .compatible = "fsl,imx7ulp-ocotp", .data = &imx7ulp_params },
565 { .compatible = "fsl,imx8mq-ocotp", .data = &imx8mq_params },
566 { .compatible = "fsl,imx8mm-ocotp", .data = &imx8mm_params },
567 { .compatible = "fsl,imx8mn-ocotp", .data = &imx8mn_params },
568 { .compatible = "fsl,imx8mp-ocotp", .data = &imx8mp_params },
571 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
573 static int imx_ocotp_probe(struct platform_device *pdev)
575 struct device *dev = &pdev->dev;
576 struct ocotp_priv *priv;
577 struct nvmem_device *nvmem;
579 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
585 priv->base = devm_platform_ioremap_resource(pdev, 0);
586 if (IS_ERR(priv->base))
587 return PTR_ERR(priv->base);
589 priv->clk = devm_clk_get(dev, NULL);
590 if (IS_ERR(priv->clk))
591 return PTR_ERR(priv->clk);
593 priv->params = of_device_get_match_data(&pdev->dev);
594 imx_ocotp_nvmem_config.size = 4 * priv->params->nregs;
595 imx_ocotp_nvmem_config.dev = dev;
596 imx_ocotp_nvmem_config.priv = priv;
597 priv->config = &imx_ocotp_nvmem_config;
599 clk_prepare_enable(priv->clk);
600 imx_ocotp_clr_err_if_set(priv);
601 clk_disable_unprepare(priv->clk);
603 nvmem = devm_nvmem_register(dev, &imx_ocotp_nvmem_config);
605 return PTR_ERR_OR_ZERO(nvmem);
608 static struct platform_driver imx_ocotp_driver = {
609 .probe = imx_ocotp_probe,
612 .of_match_table = imx_ocotp_dt_ids,
615 module_platform_driver(imx_ocotp_driver);
617 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
618 MODULE_DESCRIPTION("i.MX6/i.MX7 OCOTP fuse box driver");
619 MODULE_LICENSE("GPL v2");