drivers/nvmem/imx-ocotp.c

   1 /*
   2  * i.MX6 OCOTP fusebox driver
   3  *
   4  * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
   5  *
   6  * Based on the barebox ocotp driver,
   7  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
   8  *      Orex Computed Radiography
   9  *
  10  * Write support based on the fsl_otp driver,
  11  * Copyright (C) 2010-2013 Freescale Semiconductor, Inc
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2
  15  * as published by the Free Software Foundation.
  16  *
  17  * http://www.opensource.org/licenses/gpl-license.html
  18  * http://www.gnu.org/copyleft/gpl.html
  19  */
  20
  21 #include <linux/clk.h>
  22 #include <linux/device.h>
  23 #include <linux/io.h>
  24 #include <linux/module.h>
  25 #include <linux/nvmem-provider.h>
  26 #include <linux/of.h>
  27 #include <linux/of_device.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/slab.h>
  30 #include <linux/delay.h>
  31
  32 #define IMX_OCOTP_OFFSET_B0W0           0x400 /* Offset from base address of the
  33                                                * OTP Bank0 Word0
  34                                                */
  35 #define IMX_OCOTP_OFFSET_PER_WORD       0x10  /* Offset between the start addr
  36                                                * of two consecutive OTP words.
  37                                                */
  38
  39 #define IMX_OCOTP_ADDR_CTRL             0x0000
  40 #define IMX_OCOTP_ADDR_CTRL_SET         0x0004
  41 #define IMX_OCOTP_ADDR_CTRL_CLR         0x0008
  42 #define IMX_OCOTP_ADDR_TIMING           0x0010
  43 #define IMX_OCOTP_ADDR_DATA0            0x0020
  44 #define IMX_OCOTP_ADDR_DATA1            0x0030
  45 #define IMX_OCOTP_ADDR_DATA2            0x0040
  46 #define IMX_OCOTP_ADDR_DATA3            0x0050
  47
  48 #define IMX_OCOTP_BM_CTRL_ADDR          0x0000007F
  49 #define IMX_OCOTP_BM_CTRL_BUSY          0x00000100
  50 #define IMX_OCOTP_BM_CTRL_ERROR         0x00000200
  51 #define IMX_OCOTP_BM_CTRL_REL_SHADOWS   0x00000400
  52
  53 #define DEF_RELAX                       20      /* > 16.5ns */
  54 #define DEF_FSOURCE                     1001    /* > 1000 ns */
  55 #define DEF_STROBE_PROG                 10000   /* IPG clocks */
  56 #define IMX_OCOTP_WR_UNLOCK             0x3E770000
  57 #define IMX_OCOTP_READ_LOCKED_VAL       0xBADABADA
  58
  59 static DEFINE_MUTEX(ocotp_mutex);
  60
  61 struct ocotp_priv {
  62         struct device *dev;
  63         struct clk *clk;
  64         void __iomem *base;
  65         const struct ocotp_params *params;
  66         struct nvmem_config *config;
  67 };
  68
  69 struct ocotp_params {
  70         unsigned int nregs;
  71         unsigned int bank_address_words;
  72         void (*set_timing)(struct ocotp_priv *priv);
  73 };
  74
  75 static int imx_ocotp_wait_for_busy(void __iomem *base, u32 flags)
  76 {
  77         int count;
  78         u32 c, mask;
  79
  80         mask = IMX_OCOTP_BM_CTRL_BUSY | IMX_OCOTP_BM_CTRL_ERROR | flags;
  81
  82         for (count = 10000; count >= 0; count--) {
  83                 c = readl(base + IMX_OCOTP_ADDR_CTRL);
  84                 if (!(c & mask))
  85                         break;
  86                 cpu_relax();
  87         }
  88
  89         if (count < 0) {
  90                 /* HW_OCOTP_CTRL[ERROR] will be set under the following
  91                  * conditions:
  92                  * - A write is performed to a shadow register during a shadow
  93                  *   reload (essentially, while HW_OCOTP_CTRL[RELOAD_SHADOWS] is
  94                  *   set. In addition, the contents of the shadow register shall
  95                  *   not be updated.
  96                  * - A write is performed to a shadow register which has been
  97                  *   locked.
  98                  * - A read is performed to from a shadow register which has
  99                  *   been read locked.
 100                  * - A program is performed to a fuse word which has been locked
 101                  * - A read is performed to from a fuse word which has been read
 102                  *   locked.
 103                  */
 104                 if (c & IMX_OCOTP_BM_CTRL_ERROR)
 105                         return -EPERM;
 106                 return -ETIMEDOUT;
 107         }
 108
 109         return 0;
 110 }
 111
 112 static void imx_ocotp_clr_err_if_set(void __iomem *base)
 113 {
 114         u32 c;
 115
 116         c = readl(base + IMX_OCOTP_ADDR_CTRL);
 117         if (!(c & IMX_OCOTP_BM_CTRL_ERROR))
 118                 return;
 119
 120         writel(IMX_OCOTP_BM_CTRL_ERROR, base + IMX_OCOTP_ADDR_CTRL_CLR);
 121 }
 122
 123 static int imx_ocotp_read(void *context, unsigned int offset,
 124                           void *val, size_t bytes)
 125 {
 126         struct ocotp_priv *priv = context;
 127         unsigned int count;
 128         u32 *buf = val;
 129         int i, ret;
 130         u32 index;
 131
 132         index = offset >> 2;
 133         count = bytes >> 2;
 134
 135         if (count > (priv->params->nregs - index))
 136                 count = priv->params->nregs - index;
 137
 138         mutex_lock(&ocotp_mutex);
 139
 140         ret = clk_prepare_enable(priv->clk);
 141         if (ret < 0) {
 142                 mutex_unlock(&ocotp_mutex);
 143                 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
 144                 return ret;
 145         }
 146
 147         ret = imx_ocotp_wait_for_busy(priv->base, 0);
 148         if (ret < 0) {
 149                 dev_err(priv->dev, "timeout during read setup\n");
 150                 goto read_end;
 151         }
 152
 153         for (i = index; i < (index + count); i++) {
 154                 *buf++ = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 +
 155                                i * IMX_OCOTP_OFFSET_PER_WORD);
 156
 157                 /* 47.3.1.2
 158                  * For "read locked" registers 0xBADABADA will be returned and
 159                  * HW_OCOTP_CTRL[ERROR] will be set. It must be cleared by
 160                  * software before any new write, read or reload access can be
 161                  * issued
 162                  */
 163                 if (*(buf - 1) == IMX_OCOTP_READ_LOCKED_VAL)
 164                         imx_ocotp_clr_err_if_set(priv->base);
 165         }
 166         ret = 0;
 167
 168 read_end:
 169         clk_disable_unprepare(priv->clk);
 170         mutex_unlock(&ocotp_mutex);
 171         return ret;
 172 }
 173
 174 static void imx_ocotp_set_imx6_timing(struct ocotp_priv *priv)
 175 {
 176         unsigned long clk_rate = 0;
 177         unsigned long strobe_read, relax, strobe_prog;
 178         u32 timing = 0;
 179
 180         /* 47.3.1.3.1
 181          * Program HW_OCOTP_TIMING[STROBE_PROG] and HW_OCOTP_TIMING[RELAX]
 182          * fields with timing values to match the current frequency of the
 183          * ipg_clk. OTP writes will work at maximum bus frequencies as long
 184          * as the HW_OCOTP_TIMING parameters are set correctly.
 185          */
 186         clk_rate = clk_get_rate(priv->clk);
 187
 188         relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
 189         strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
 190         strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
 191
 192         timing = strobe_prog & 0x00000FFF;
 193         timing |= (relax       << 12) & 0x0000F000;
 194         timing |= (strobe_read << 16) & 0x003F0000;
 195
 196         writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
 197 }
 198
 199 static void imx_ocotp_set_imx7_timing(struct ocotp_priv *priv)
 200 {
 201         unsigned long clk_rate = 0;
 202         u64 fsource, strobe_prog;
 203         u32 timing = 0;
 204
 205         /* i.MX 7Solo Applications Processor Reference Manual, Rev. 0.1
 206          * 6.4.3.3
 207          */
 208         clk_rate = clk_get_rate(priv->clk);
 209         fsource = DIV_ROUND_UP_ULL((u64)clk_rate * DEF_FSOURCE,
 210                                    NSEC_PER_SEC) + 1;
 211         strobe_prog = DIV_ROUND_CLOSEST_ULL((u64)clk_rate * DEF_STROBE_PROG,
 212                                             NSEC_PER_SEC) + 1;
 213
 214         timing = strobe_prog & 0x00000FFF;
 215         timing |= (fsource << 12) & 0x000FF000;
 216
 217         writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
 218 }
 219
 220 static int imx_ocotp_write(void *context, unsigned int offset, void *val,
 221                            size_t bytes)
 222 {
 223         struct ocotp_priv *priv = context;
 224         u32 *buf = val;
 225         int ret;
 226
 227         u32 ctrl;
 228         u8 waddr;
 229         u8 word = 0;
 230
 231         /* allow only writing one complete OTP word at a time */
 232         if ((bytes != priv->config->word_size) ||
 233             (offset % priv->config->word_size))
 234                 return -EINVAL;
 235
 236         mutex_lock(&ocotp_mutex);
 237
 238         ret = clk_prepare_enable(priv->clk);
 239         if (ret < 0) {
 240                 mutex_unlock(&ocotp_mutex);
 241                 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
 242                 return ret;
 243         }
 244
 245         /* Setup the write timing values */
 246         priv->params->set_timing(priv);
 247
 248         /* 47.3.1.3.2
 249          * Check that HW_OCOTP_CTRL[BUSY] and HW_OCOTP_CTRL[ERROR] are clear.
 250          * Overlapped accesses are not supported by the controller. Any pending
 251          * write or reload must be completed before a write access can be
 252          * requested.
 253          */
 254         ret = imx_ocotp_wait_for_busy(priv->base, 0);
 255         if (ret < 0) {
 256                 dev_err(priv->dev, "timeout during timing setup\n");
 257                 goto write_end;
 258         }
 259
 260         /* 47.3.1.3.3
 261          * Write the requested address to HW_OCOTP_CTRL[ADDR] and program the
 262          * unlock code into HW_OCOTP_CTRL[WR_UNLOCK]. This must be programmed
 263          * for each write access. The lock code is documented in the register
 264          * description. Both the unlock code and address can be written in the
 265          * same operation.
 266          */
 267         if (priv->params->bank_address_words != 0) {
 268                 /*
 269                  * In banked/i.MX7 mode the OTP register bank goes into waddr
 270                  * see i.MX 7Solo Applications Processor Reference Manual, Rev.
 271                  * 0.1 section 6.4.3.1
 272                  */
 273                 offset = offset / priv->config->word_size;
 274                 waddr = offset / priv->params->bank_address_words;
 275                 word  = offset & (priv->params->bank_address_words - 1);
 276         } else {
 277                 /*
 278                  * Non-banked i.MX6 mode.
 279                  * OTP write/read address specifies one of 128 word address
 280                  * locations
 281                  */
 282                 waddr = offset / 4;
 283         }
 284
 285         ctrl = readl(priv->base + IMX_OCOTP_ADDR_CTRL);
 286         ctrl &= ~IMX_OCOTP_BM_CTRL_ADDR;
 287         ctrl |= waddr & IMX_OCOTP_BM_CTRL_ADDR;
 288         ctrl |= IMX_OCOTP_WR_UNLOCK;
 289
 290         writel(ctrl, priv->base + IMX_OCOTP_ADDR_CTRL);
 291
 292         /* 47.3.1.3.4
 293          * Write the data to the HW_OCOTP_DATA register. This will automatically
 294          * set HW_OCOTP_CTRL[BUSY] and clear HW_OCOTP_CTRL[WR_UNLOCK]. To
 295          * protect programming same OTP bit twice, before program OCOTP will
 296          * automatically read fuse value in OTP and use read value to mask
 297          * program data. The controller will use masked program data to program
 298          * a 32-bit word in the OTP per the address in HW_OCOTP_CTRL[ADDR]. Bit
 299          * fields with 1's will result in that OTP bit being programmed. Bit
 300          * fields with 0's will be ignored. At the same time that the write is
 301          * accepted, the controller makes an internal copy of
 302          * HW_OCOTP_CTRL[ADDR] which cannot be updated until the next write
 303          * sequence is initiated. This copy guarantees that erroneous writes to
 304          * HW_OCOTP_CTRL[ADDR] will not affect an active write operation. It
 305          * should also be noted that during the programming HW_OCOTP_DATA will
 306          * shift right (with zero fill). This shifting is required to program
 307          * the OTP serially. During the write operation, HW_OCOTP_DATA cannot be
 308          * modified.
 309          * Note: on i.MX7 there are four data fields to write for banked write
 310          *       with the fuse blowing operation only taking place after data0
 311          *       has been written. This is why data0 must always be the last
 312          *       register written.
 313          */
 314         if (priv->params->bank_address_words != 0) {
 315                 /* Banked/i.MX7 mode */
 316                 switch (word) {
 317                 case 0:
 318                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
 319                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
 320                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
 321                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA0);
 322                         break;
 323                 case 1:
 324                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA1);
 325                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
 326                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
 327                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
 328                         break;
 329                 case 2:
 330                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
 331                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA2);
 332                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA3);
 333                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
 334                         break;
 335                 case 3:
 336                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA1);
 337                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA2);
 338                         writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA3);
 339                         writel(0, priv->base + IMX_OCOTP_ADDR_DATA0);
 340                         break;
 341                 }
 342         } else {
 343                 /* Non-banked i.MX6 mode */
 344                 writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA0);
 345         }
 346
 347         /* 47.4.1.4.5
 348          * Once complete, the controller will clear BUSY. A write request to a
 349          * protected or locked region will result in no OTP access and no
 350          * setting of HW_OCOTP_CTRL[BUSY]. In addition HW_OCOTP_CTRL[ERROR] will
 351          * be set. It must be cleared by software before any new write access
 352          * can be issued.
 353          */
 354         ret = imx_ocotp_wait_for_busy(priv->base, 0);
 355         if (ret < 0) {
 356                 if (ret == -EPERM) {
 357                         dev_err(priv->dev, "failed write to locked region");
 358                         imx_ocotp_clr_err_if_set(priv->base);
 359                 } else {
 360                         dev_err(priv->dev, "timeout during data write\n");
 361                 }
 362                 goto write_end;
 363         }
 364
 365         /* 47.3.1.4
 366          * Write Postamble: Due to internal electrical characteristics of the
 367          * OTP during writes, all OTP operations following a write must be
 368          * separated by 2 us after the clearing of HW_OCOTP_CTRL_BUSY following
 369          * the write.
 370          */
 371         udelay(2);
 372
 373         /* reload all shadow registers */
 374         writel(IMX_OCOTP_BM_CTRL_REL_SHADOWS,
 375                priv->base + IMX_OCOTP_ADDR_CTRL_SET);
 376         ret = imx_ocotp_wait_for_busy(priv->base,
 377                                       IMX_OCOTP_BM_CTRL_REL_SHADOWS);
 378         if (ret < 0) {
 379                 dev_err(priv->dev, "timeout during shadow register reload\n");
 380                 goto write_end;
 381         }
 382
 383 write_end:
 384         clk_disable_unprepare(priv->clk);
 385         mutex_unlock(&ocotp_mutex);
 386         if (ret < 0)
 387                 return ret;
 388         return bytes;
 389 }
 390
 391 static struct nvmem_config imx_ocotp_nvmem_config = {
 392         .name = "imx-ocotp",
 393         .read_only = false,
 394         .word_size = 4,
 395         .stride = 4,
 396         .reg_read = imx_ocotp_read,
 397         .reg_write = imx_ocotp_write,
 398 };
 399
 400 static const struct ocotp_params imx6q_params = {
 401         .nregs = 128,
 402         .bank_address_words = 0,
 403         .set_timing = imx_ocotp_set_imx6_timing,
 404 };
 405
 406 static const struct ocotp_params imx6sl_params = {
 407         .nregs = 64,
 408         .bank_address_words = 0,
 409         .set_timing = imx_ocotp_set_imx6_timing,
 410 };
 411
 412 static const struct ocotp_params imx6sx_params = {
 413         .nregs = 128,
 414         .bank_address_words = 0,
 415         .set_timing = imx_ocotp_set_imx6_timing,
 416 };
 417
 418 static const struct ocotp_params imx6ul_params = {
 419         .nregs = 128,
 420         .bank_address_words = 0,
 421         .set_timing = imx_ocotp_set_imx6_timing,
 422 };
 423
 424 static const struct ocotp_params imx7d_params = {
 425         .nregs = 64,
 426         .bank_address_words = 4,
 427         .set_timing = imx_ocotp_set_imx7_timing,
 428 };
 429
 430 static const struct of_device_id imx_ocotp_dt_ids[] = {
 431         { .compatible = "fsl,imx6q-ocotp",  .data = &imx6q_params },
 432         { .compatible = "fsl,imx6sl-ocotp", .data = &imx6sl_params },
 433         { .compatible = "fsl,imx6sx-ocotp", .data = &imx6sx_params },
 434         { .compatible = "fsl,imx6ul-ocotp", .data = &imx6ul_params },
 435         { .compatible = "fsl,imx7d-ocotp",  .data = &imx7d_params },
 436         { },
 437 };
 438 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
 439
 440 static int imx_ocotp_probe(struct platform_device *pdev)
 441 {
 442         const struct of_device_id *of_id;
 443         struct device *dev = &pdev->dev;
 444         struct resource *res;
 445         struct ocotp_priv *priv;
 446         struct nvmem_device *nvmem;
 447
 448         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 449         if (!priv)
 450                 return -ENOMEM;
 451
 452         priv->dev = dev;
 453
 454         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 455         priv->base = devm_ioremap_resource(dev, res);
 456         if (IS_ERR(priv->base))
 457                 return PTR_ERR(priv->base);
 458
 459         priv->clk = devm_clk_get(dev, NULL);
 460         if (IS_ERR(priv->clk))
 461                 return PTR_ERR(priv->clk);
 462
 463         of_id = of_match_device(imx_ocotp_dt_ids, dev);
 464         priv->params = of_device_get_match_data(&pdev->dev);
 465         imx_ocotp_nvmem_config.size = 4 * priv->params->nregs;
 466         imx_ocotp_nvmem_config.dev = dev;
 467         imx_ocotp_nvmem_config.priv = priv;
 468         priv->config = &imx_ocotp_nvmem_config;
 469         nvmem = nvmem_register(&imx_ocotp_nvmem_config);
 470
 471         if (IS_ERR(nvmem))
 472                 return PTR_ERR(nvmem);
 473
 474         platform_set_drvdata(pdev, nvmem);
 475
 476         return 0;
 477 }
 478
 479 static int imx_ocotp_remove(struct platform_device *pdev)
 480 {
 481         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 482
 483         return nvmem_unregister(nvmem);
 484 }
 485
 486 static struct platform_driver imx_ocotp_driver = {
 487         .probe  = imx_ocotp_probe,
 488         .remove = imx_ocotp_remove,
 489         .driver = {
 490                 .name   = "imx_ocotp",
 491                 .of_match_table = imx_ocotp_dt_ids,
 492         },
 493 };
 494 module_platform_driver(imx_ocotp_driver);
 495
 496 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
 497 MODULE_DESCRIPTION("i.MX6/i.MX7 OCOTP fuse box driver");
 498 MODULE_LICENSE("GPL v2");