drivers/nvmem/imx-ocotp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * i.MX6 OCOTP fusebox driver
   4  *
   5  * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
   6  *
   7  * Based on the barebox ocotp driver,
   8  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
   9  *      Orex Computed Radiography
  10  *
  11  * Write support based on the fsl_otp driver,
  12  * Copyright (C) 2010-2013 Freescale Semiconductor, Inc
  13  */
  14
  15 #include <linux/clk.h>
  16 #include <linux/device.h>
  17 #include <linux/io.h>
  18 #include <linux/module.h>
  19 #include <linux/nvmem-provider.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/slab.h>
  24 #include <linux/delay.h>
  25
  26 #define IMX_OCOTP_OFFSET_B0W0           0x400 /* Offset from base address of the
  27                                                * OTP Bank0 Word0
  28                                                */
  29 #define IMX_OCOTP_OFFSET_PER_WORD       0x10  /* Offset between the start addr
  30                                                * of two consecutive OTP words.
  31                                                */
  32
  33 #define IMX_OCOTP_ADDR_CTRL             0x0000
  34 #define IMX_OCOTP_ADDR_CTRL_SET         0x0004
  35 #define IMX_OCOTP_ADDR_CTRL_CLR         0x0008
  36 #define IMX_OCOTP_ADDR_TIMING           0x0010
  37 #define IMX_OCOTP_ADDR_DATA0            0x0020
  38 #define IMX_OCOTP_ADDR_DATA1            0x0030
  39 #define IMX_OCOTP_ADDR_DATA2            0x0040
  40 #define IMX_OCOTP_ADDR_DATA3            0x0050
  41
  42 #define IMX_OCOTP_BM_CTRL_ADDR          0x000000FF
  43 #define IMX_OCOTP_BM_CTRL_BUSY          0x00000100
  44 #define IMX_OCOTP_BM_CTRL_ERROR         0x00000200
  45 #define IMX_OCOTP_BM_CTRL_REL_SHADOWS   0x00000400
  46
  47 #define TIMING_STROBE_PROG_US           10      /* Min time to blow a fuse */
  48 #define TIMING_STROBE_READ_NS           37      /* Min time before read */
  49 #define TIMING_RELAX_NS                 17
  50 #define DEF_FSOURCE                     1001    /* > 1000 ns */
  51 #define DEF_STROBE_PROG                 10000   /* IPG clocks */
  52 #define IMX_OCOTP_WR_UNLOCK             0x3E770000
  53 #define IMX_OCOTP_READ_LOCKED_VAL       0xBADABADA
  54
  55 static DEFINE_MUTEX(ocotp_mutex);
  56
  57 struct ocotp_priv {
  58         struct device *dev;
  59         struct clk *clk;
  60         void __iomem *base;
  61         const struct ocotp_params *params;
  62         struct nvmem_config *config;
  63 };
  64
  65 struct ocotp_params {
  66         unsigned int nregs;
  67         unsigned int bank_address_words;
  68         void (*set_timing)(struct ocotp_priv *priv);
  69 };
  70
  71 static int imx_ocotp_wait_for_busy(void __iomem *base, u32 flags)
  72 {
  73         int count;
  74         u32 c, mask;
  75
  76         mask = IMX_OCOTP_BM_CTRL_BUSY | IMX_OCOTP_BM_CTRL_ERROR | flags;
  77
  78         for (count = 10000; count >= 0; count--) {
  79                 c = readl(base + IMX_OCOTP_ADDR_CTRL);
  80                 if (!(c & mask))
  81                         break;
  82                 cpu_relax();
  83         }
  84
  85         if (count < 0) {
  86                 /* HW_OCOTP_CTRL[ERROR] will be set under the following
  87                  * conditions:
  88                  * - A write is performed to a shadow register during a shadow
  89                  *   reload (essentially, while HW_OCOTP_CTRL[RELOAD_SHADOWS] is
  90                  *   set. In addition, the contents of the shadow register shall
  91                  *   not be updated.
  92                  * - A write is performed to a shadow register which has been
  93                  *   locked.
  94                  * - A read is performed to from a shadow register which has
  95                  *   been read locked.
  96                  * - A program is performed to a fuse word which has been locked
  97                  * - A read is performed to from a fuse word which has been read
  98                  *   locked.
  99                  */
 100                 if (c & IMX_OCOTP_BM_CTRL_ERROR)
 101                         return -EPERM;
 102                 return -ETIMEDOUT;
 103         }
 104
 105         return 0;
 106 }
 107
 108 static void imx_ocotp_clr_err_if_set(void __iomem *base)
 109 {
 110         u32 c;
 111
 112         c = readl(base + IMX_OCOTP_ADDR_CTRL);
 113         if (!(c & IMX_OCOTP_BM_CTRL_ERROR))
 114                 return;
 115
 116         writel(IMX_OCOTP_BM_CTRL_ERROR, base + IMX_OCOTP_ADDR_CTRL_CLR);
 117 }
 118
 119 static int imx_ocotp_read(void *context, unsigned int offset,
 120                           void *val, size_t bytes)
 121 {
 122         struct ocotp_priv *priv = context;
 123         unsigned int count;
 124         u32 *buf = val;
 125         int i, ret;
 126         u32 index;
 127
 128         index = offset >> 2;
 129         count = bytes >> 2;
 130
 131         if (count > (priv->params->nregs - index))
 132                 count = priv->params->nregs - index;
 133
 134         mutex_lock(&ocotp_mutex);
 135
 136         ret = clk_prepare_enable(priv->clk);
 137         if (ret < 0) {
 138                 mutex_unlock(&ocotp_mutex);
 139                 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
 140                 return ret;
 141         }
 142
 143         ret = imx_ocotp_wait_for_busy(priv->base, 0);
 144         if (ret < 0) {
 145                 dev_err(priv->dev, "timeout during read setup\n");
 146                 goto read_end;
 147         }
 148
 149         for (i = index; i < (index + count); i++) {
 150                 *buf++ = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 +
 151                                i * IMX_OCOTP_OFFSET_PER_WORD);
 152
 153                 /* 47.3.1.2
 154                  * For "read locked" registers 0xBADABADA will be returned and
 155                  * HW_OCOTP_CTRL[ERROR] will be set. It must be cleared by
 156                  * software before any new write, read or reload access can be
 157                  * issued
 158                  */
 159                 if (*(buf - 1) == IMX_OCOTP_READ_LOCKED_VAL)
 160                         imx_ocotp_clr_err_if_set(priv->base);
 161         }
 162         ret = 0;
 163
 164 read_end:
 165         clk_disable_unprepare(priv->clk);
 166         mutex_unlock(&ocotp_mutex);
 167         return ret;
 168 }
 169
 170 static void imx_ocotp_set_imx6_timing(struct ocotp_priv *priv)
 171 {
 172         unsigned long clk_rate = 0;
 173         unsigned long strobe_read, relax, strobe_prog;
 174         u32 timing = 0;
 175
 176         /* 47.3.1.3.1
 177          * Program HW_OCOTP_TIMING[STROBE_PROG] and HW_OCOTP_TIMING[RELAX]
 178          * fields with timing values to match the current frequency of the
 179          * ipg_clk. OTP writes will work at maximum bus frequencies as long
 180          * as the HW_OCOTP_TIMING parameters are set correctly.
 181          *
 182          * Note: there are minimum timings required to ensure an OTP fuse burns
 183          * correctly that are independent of the ipg_clk. Those values are not
 184          * formally documented anywhere however, working from the minimum
 185          * timings given in u-boot we can say:
 186          *
 187          * - Minimum STROBE_PROG time is 10 microseconds. Intuitively 10
 188          *   microseconds feels about right as representative of a minimum time
 189          *   to physically burn out a fuse.
 190          *
 191          * - Minimum STROBE_READ i.e. the time to wait post OTP fuse burn before
 192          *   performing another read is 37 nanoseconds
 193          *
 194          * - Minimum RELAX timing is 17 nanoseconds. This final RELAX minimum
 195          *   timing is not entirely clear the documentation says "This
 196          *   count value specifies the time to add to all default timing
 197          *   parameters other than the Tpgm and Trd. It is given in number
 198          *   of ipg_clk periods." where Tpgm and Trd refer to STROBE_PROG
 199          *   and STROBE_READ respectively. What the other timing parameters
 200          *   are though, is not specified. Experience shows a zero RELAX
 201          *   value will mess up a re-load of the shadow registers post OTP
 202          *   burn.
 203          */
 204         clk_rate = clk_get_rate(priv->clk);
 205
 206         relax = DIV_ROUND_UP(clk_rate * TIMING_RELAX_NS, 1000000000) - 1;
 207         strobe_read = DIV_ROUND_UP(clk_rate * TIMING_STROBE_READ_NS,
 208                                    1000000000);
 209         strobe_read += 2 * (relax + 1) - 1;
 210         strobe_prog = DIV_ROUND_CLOSEST(clk_rate * TIMING_STROBE_PROG_US,
 211                                         1000000);
 212         strobe_prog += 2 * (relax + 1) - 1;
 213
 214         timing = readl(priv->base + IMX_OCOTP_ADDR_TIMING) & 0x0FC00000;
 215         timing |= strobe_prog & 0x00000FFF;
 216         timing |= (relax       << 12) & 0x0000F000;
 217         timing |= (strobe_read << 16) & 0x003F0000;
 218
 219         writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
 220 }
 221
 222 static void imx_ocotp_set_imx7_timing(struct ocotp_priv *priv)
 223 {
 224         unsigned long clk_rate = 0;
 225         u64 fsource, strobe_prog;
 226         u32 timing = 0;
 227
 228         /* i.MX 7Solo Applications Processor Reference Manual, Rev. 0.1
 229          * 6.4.3.3
 230          */
 231         clk_rate = clk_get_rate(priv->clk);
 232         fsource = DIV_ROUND_UP_ULL((u64)clk_rate * DEF_FSOURCE,
 233                                    NSEC_PER_SEC) + 1;
 234         strobe_prog = DIV_ROUND_CLOSEST_ULL((u64)clk_rate * DEF_STROBE_PROG,
 235                                             NSEC_PER_SEC) + 1;
 236
 237         timing = strobe_prog & 0x00000FFF;
 238         timing |= (fsource << 12) & 0x000FF000;
 239
 240         writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
 241 }
 242
 243 static int imx_ocotp_write(void *context, unsigned int offset, void *val,
 244                            size_t bytes)
 245 {
 246         struct ocotp_priv *priv = context;
 247         u32 *buf = val;
 248         int ret;
 249
 250         u32 ctrl;
 251         u8 waddr;
 252         u8 word = 0;
 253
 254         /* allow only writing one complete OTP word at a time */
 255         if ((bytes != priv->config->word_size) ||
 256             (offset % priv->config->word_size))
 257                 return -EINVAL;
 258
 259         mutex_lock(&ocotp_mutex);
 260
 261         ret = clk_prepare_enable(priv->clk);
 262         if (ret < 0) {
 263                 mutex_unlock(&ocotp_mutex);
 264                 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
 265                 return ret;
 266         }
 267
 268         /* Setup the write timing values */
 269         priv->params->set_timing(priv);
 270
 271         /* 47.3.1.3.2
 272          * Check that HW_OCOTP_CTRL[BUSY] and HW_OCOTP_CTRL[ERROR] are clear.
 273          * Overlapped accesses are not supported by the controller. Any pending
 274          * write or reload must be completed before a write access can be
 275          * requested.
 276          */
 277         ret = imx_ocotp_wait_for_busy(priv->base, 0);
 278         if (ret < 0) {
 279                 dev_err(priv->dev, "timeout during timing setup\n");
 280                 goto write_end;
 281         }
 282
 283         /* 47.3.1.3.3
 284          * Write the requested address to HW_OCOTP_CTRL[ADDR] and program the
 285          * unlock code into HW_OCOTP_CTRL[WR_UNLOCK]. This must be programmed
 286          * for each write access. The lock code is documented in the register
 287          * description. Both the unlock code and address can be written in the
 288          * same operation.
 289          */
 290         if (priv->params->bank_address_words != 0) {
 291                 /*
 292                  * In banked/i.MX7 mode the OTP register bank goes into waddr
 293                  * see i.MX 7Solo Applications Processor Reference Manual, Rev.
 294                  * 0.1 section 6.4.3.1
 295                  */
 296                 offset = offset / priv->config->word_size;
 297                 waddr = offset / priv->params->bank_address_words;
 298                 word  = offset & (priv->params->bank_address_words - 1);
 299         } else {
 300                 /*
 301                  * Non-banked i.MX6 mode.
 302                  * OTP write/read address specifies one of 128 word address
 303                  * locations
 304                  */
 305                 waddr = offset / 4;
 306         }
 307
 308         ctrl = readl(priv->base + IMX_OCOTP_ADDR_CTRL);
 309         ctrl &= ~IMX_OCOTP_BM_CTRL_ADDR;
 310         ctrl |= waddr & IMX_OCOTP_BM_CTRL_ADDR;
 311         ctrl |= IMX_OCOTP_WR_UNLOCK;
 312
 313         writel(ctrl, priv->base + IMX_OCOTP_ADDR_CTRL);
 314
 315         /* 47.3.1.3.4
 316          * Write the data to the HW_OCOTP_DATA register. This will automatically
 317          * set HW_OCOTP_CTRL[BUSY] and clear HW_OCOTP_CTRL[WR_UNLOCK]. To
 318          * protect programming same OTP bit twice, before program OCOTP will
 319          * automatically read fuse value in OTP and use read value to mask
 320          * program data. The controller will use masked program data to program
 321          * a 32-bit word in the OTP per the address in HW_OCOTP_CTRL[ADDR]. Bit
 322          * fields with 1's will result in that OTP bit being programmed. Bit
 323          * fields with 0's will be ignored. At the same time that the write is
 324          * accepted, the controller makes an internal copy of
 325          * HW_OCOTP_CTRL[ADDR] which cannot be updated until the next write
 326          * sequence is initiated. This copy guarantees that erroneous writes to
 327          * HW_OCOTP_CTRL[ADDR] will not affect an active write operation. It
 328          * should also be noted that during the programming HW_OCOTP_DATA will
 329          * shift right (with zero fill). This shifting is required to program
 330          * the OTP serially. During the write operation, HW_OCOTP_DATA cannot be
 331          * modified.
 332          * Note: on i.MX7 there are four data fields to write for banked write
 333          *       with the fuse blowing operation only taking place after data0
 334          *       has been written. This is why data0 must always be the last
 335          *       register written.
 336          */
 337         if (priv->params->bank_address_words != 0) {
 338                 /* Banked/i.MX7 mode */
 339                 switch (word) {
 340                 case 0:
 341                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
 342                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
 343                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
 344                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA0);
 345                         break;
 346                 case 1:
 347                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA1);
 348                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
 349                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
 350                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
 351                         break;
 352                 case 2:
 353                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
 354                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA2);
 355                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
 356                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
 357                         break;
 358                 case 3:
 359                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
 360                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
 361                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA3);
 362                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
 363                         break;
 364                 }
 365         } else {
 366                 /* Non-banked i.MX6 mode */
 367                 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA0);
 368         }
 369
 370         /* 47.4.1.4.5
 371          * Once complete, the controller will clear BUSY. A write request to a
 372          * protected or locked region will result in no OTP access and no
 373          * setting of HW_OCOTP_CTRL[BUSY]. In addition HW_OCOTP_CTRL[ERROR] will
 374          * be set. It must be cleared by software before any new write access
 375          * can be issued.
 376          */
 377         ret = imx_ocotp_wait_for_busy(priv->base, 0);
 378         if (ret < 0) {
 379                 if (ret == -EPERM) {
 380                         dev_err(priv->dev, "failed write to locked region");
 381                         imx_ocotp_clr_err_if_set(priv->base);
 382                 } else {
 383                         dev_err(priv->dev, "timeout during data write\n");
 384                 }
 385                 goto write_end;
 386         }
 387
 388         /* 47.3.1.4
 389          * Write Postamble: Due to internal electrical characteristics of the
 390          * OTP during writes, all OTP operations following a write must be
 391          * separated by 2 us after the clearing of HW_OCOTP_CTRL_BUSY following
 392          * the write.
 393          */
 394         udelay(2);
 395
 396         /* reload all shadow registers */
 397         writel(IMX_OCOTP_BM_CTRL_REL_SHADOWS,
 398                priv->base + IMX_OCOTP_ADDR_CTRL_SET);
 399         ret = imx_ocotp_wait_for_busy(priv->base,
 400                                       IMX_OCOTP_BM_CTRL_REL_SHADOWS);
 401         if (ret < 0) {
 402                 dev_err(priv->dev, "timeout during shadow register reload\n");
 403                 goto write_end;
 404         }
 405
 406 write_end:
 407         clk_disable_unprepare(priv->clk);
 408         mutex_unlock(&ocotp_mutex);
 409         if (ret < 0)
 410                 return ret;
 411         return bytes;
 412 }
 413
 414 static struct nvmem_config imx_ocotp_nvmem_config = {
 415         .name = "imx-ocotp",
 416         .read_only = false,
 417         .word_size = 4,
 418         .stride = 4,
 419         .reg_read = imx_ocotp_read,
 420         .reg_write = imx_ocotp_write,
 421 };
 422
 423 static const struct ocotp_params imx6q_params = {
 424         .nregs = 128,
 425         .bank_address_words = 0,
 426         .set_timing = imx_ocotp_set_imx6_timing,
 427 };
 428
 429 static const struct ocotp_params imx6sl_params = {
 430         .nregs = 64,
 431         .bank_address_words = 0,
 432         .set_timing = imx_ocotp_set_imx6_timing,
 433 };
 434
 435 static const struct ocotp_params imx6sll_params = {
 436         .nregs = 128,
 437         .bank_address_words = 0,
 438         .set_timing = imx_ocotp_set_imx6_timing,
 439 };
 440
 441 static const struct ocotp_params imx6sx_params = {
 442         .nregs = 128,
 443         .bank_address_words = 0,
 444         .set_timing = imx_ocotp_set_imx6_timing,
 445 };
 446
 447 static const struct ocotp_params imx6ul_params = {
 448         .nregs = 128,
 449         .bank_address_words = 0,
 450         .set_timing = imx_ocotp_set_imx6_timing,
 451 };
 452
 453 static const struct ocotp_params imx6ull_params = {
 454         .nregs = 64,
 455         .bank_address_words = 0,
 456         .set_timing = imx_ocotp_set_imx6_timing,
 457 };
 458
 459 static const struct ocotp_params imx7d_params = {
 460         .nregs = 64,
 461         .bank_address_words = 4,
 462         .set_timing = imx_ocotp_set_imx7_timing,
 463 };
 464
 465 static const struct ocotp_params imx7ulp_params = {
 466         .nregs = 256,
 467         .bank_address_words = 0,
 468 };
 469
 470 static const struct ocotp_params imx8mq_params = {
 471         .nregs = 256,
 472         .bank_address_words = 0,
 473         .set_timing = imx_ocotp_set_imx6_timing,
 474 };
 475
 476 static const struct ocotp_params imx8mm_params = {
 477         .nregs = 256,
 478         .bank_address_words = 0,
 479         .set_timing = imx_ocotp_set_imx6_timing,
 480 };
 481
 482 static const struct ocotp_params imx8mn_params = {
 483         .nregs = 256,
 484         .bank_address_words = 0,
 485         .set_timing = imx_ocotp_set_imx6_timing,
 486 };
 487
 488 static const struct of_device_id imx_ocotp_dt_ids[] = {
 489         { .compatible = "fsl,imx6q-ocotp",  .data = &imx6q_params },
 490         { .compatible = "fsl,imx6sl-ocotp", .data = &imx6sl_params },
 491         { .compatible = "fsl,imx6sx-ocotp", .data = &imx6sx_params },
 492         { .compatible = "fsl,imx6ul-ocotp", .data = &imx6ul_params },
 493         { .compatible = "fsl,imx6ull-ocotp", .data = &imx6ull_params },
 494         { .compatible = "fsl,imx7d-ocotp",  .data = &imx7d_params },
 495         { .compatible = "fsl,imx6sll-ocotp", .data = &imx6sll_params },
 496         { .compatible = "fsl,imx7ulp-ocotp", .data = &imx7ulp_params },
 497         { .compatible = "fsl,imx8mq-ocotp", .data = &imx8mq_params },
 498         { .compatible = "fsl,imx8mm-ocotp", .data = &imx8mm_params },
 499         { .compatible = "fsl,imx8mn-ocotp", .data = &imx8mn_params },
 500         { },
 501 };
 502 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
 503
 504 static int imx_ocotp_probe(struct platform_device *pdev)
 505 {
 506         struct device *dev = &pdev->dev;
 507         struct ocotp_priv *priv;
 508         struct nvmem_device *nvmem;
 509
 510         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 511         if (!priv)
 512                 return -ENOMEM;
 513
 514         priv->dev = dev;
 515
 516         priv->base = devm_platform_ioremap_resource(pdev, 0);
 517         if (IS_ERR(priv->base))
 518                 return PTR_ERR(priv->base);
 519
 520         priv->clk = devm_clk_get(dev, NULL);
 521         if (IS_ERR(priv->clk))
 522                 return PTR_ERR(priv->clk);
 523
 524         priv->params = of_device_get_match_data(&pdev->dev);
 525         imx_ocotp_nvmem_config.size = 4 * priv->params->nregs;
 526         imx_ocotp_nvmem_config.dev = dev;
 527         imx_ocotp_nvmem_config.priv = priv;
 528         priv->config = &imx_ocotp_nvmem_config;
 529         nvmem = devm_nvmem_register(dev, &imx_ocotp_nvmem_config);
 530
 531
 532         return PTR_ERR_OR_ZERO(nvmem);
 533 }
 534
 535 static struct platform_driver imx_ocotp_driver = {
 536         .probe  = imx_ocotp_probe,
 537         .driver = {
 538                 .name   = "imx_ocotp",
 539                 .of_match_table = imx_ocotp_dt_ids,
 540         },
 541 };
 542 module_platform_driver(imx_ocotp_driver);
 543
 544 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
 545 MODULE_DESCRIPTION("i.MX6/i.MX7 OCOTP fuse box driver");
 546 MODULE_LICENSE("GPL v2");