drivers/mtd/nand/raw/nand_micron.c

   1 /*
   2  * Copyright (C) 2017 Free Electrons
   3  * Copyright (C) 2017 NextThing Co
   4  *
   5  * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/mtd/rawnand.h>
  19 #include <linux/slab.h>
  20
  21 /*
  22  * Special Micron status bit 3 indicates that the block has been
  23  * corrected by on-die ECC and should be rewritten.
  24  */
  25 #define NAND_ECC_STATUS_WRITE_RECOMMENDED       BIT(3)
  26
  27 /*
  28  * On chips with 8-bit ECC and additional bit can be used to distinguish
  29  * cases where a errors were corrected without needing a rewrite
  30  *
  31  * Bit 4 Bit 3 Bit 0 Description
  32  * ----- ----- ----- -----------
  33  * 0     0     0     No Errors
  34  * 0     0     1     Multiple uncorrected errors
  35  * 0     1     0     4 - 6 errors corrected, recommend rewrite
  36  * 0     1     1     Reserved
  37  * 1     0     0     1 - 3 errors corrected
  38  * 1     0     1     Reserved
  39  * 1     1     0     7 - 8 errors corrected, recommend rewrite
  40  */
  41 #define NAND_ECC_STATUS_MASK            (BIT(4) | BIT(3) | BIT(0))
  42 #define NAND_ECC_STATUS_UNCORRECTABLE   BIT(0)
  43 #define NAND_ECC_STATUS_4_6_CORRECTED   BIT(3)
  44 #define NAND_ECC_STATUS_1_3_CORRECTED   BIT(4)
  45 #define NAND_ECC_STATUS_7_8_CORRECTED   (BIT(4) | BIT(3))
  46
  47 struct nand_onfi_vendor_micron {
  48         u8 two_plane_read;
  49         u8 read_cache;
  50         u8 read_unique_id;
  51         u8 dq_imped;
  52         u8 dq_imped_num_settings;
  53         u8 dq_imped_feat_addr;
  54         u8 rb_pulldown_strength;
  55         u8 rb_pulldown_strength_feat_addr;
  56         u8 rb_pulldown_strength_num_settings;
  57         u8 otp_mode;
  58         u8 otp_page_start;
  59         u8 otp_data_prot_addr;
  60         u8 otp_num_pages;
  61         u8 otp_feat_addr;
  62         u8 read_retry_options;
  63         u8 reserved[72];
  64         u8 param_revision;
  65 } __packed;
  66
  67 struct micron_on_die_ecc {
  68         bool forced;
  69         bool enabled;
  70         void *rawbuf;
  71 };
  72
  73 struct micron_nand {
  74         struct micron_on_die_ecc ecc;
  75 };
  76
  77 static int micron_nand_setup_read_retry(struct mtd_info *mtd, int retry_mode)
  78 {
  79         struct nand_chip *chip = mtd_to_nand(mtd);
  80         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = {retry_mode};
  81
  82         return nand_set_features(chip, ONFI_FEATURE_ADDR_READ_RETRY, feature);
  83 }
  84
  85 /*
  86  * Configure chip properties from Micron vendor-specific ONFI table
  87  */
  88 static int micron_nand_onfi_init(struct nand_chip *chip)
  89 {
  90         struct nand_parameters *p = &chip->parameters;
  91
  92         if (p->onfi) {
  93                 struct nand_onfi_vendor_micron *micron = (void *)p->onfi->vendor;
  94
  95                 chip->read_retries = micron->read_retry_options;
  96                 chip->setup_read_retry = micron_nand_setup_read_retry;
  97         }
  98
  99         if (p->supports_set_get_features) {
 100                 set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->set_feature_list);
 101                 set_bit(ONFI_FEATURE_ON_DIE_ECC, p->set_feature_list);
 102                 set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->get_feature_list);
 103                 set_bit(ONFI_FEATURE_ON_DIE_ECC, p->get_feature_list);
 104         }
 105
 106         return 0;
 107 }
 108
 109 static int micron_nand_on_die_4_ooblayout_ecc(struct mtd_info *mtd,
 110                                               int section,
 111                                               struct mtd_oob_region *oobregion)
 112 {
 113         if (section >= 4)
 114                 return -ERANGE;
 115
 116         oobregion->offset = (section * 16) + 8;
 117         oobregion->length = 8;
 118
 119         return 0;
 120 }
 121
 122 static int micron_nand_on_die_4_ooblayout_free(struct mtd_info *mtd,
 123                                                int section,
 124                                                struct mtd_oob_region *oobregion)
 125 {
 126         if (section >= 4)
 127                 return -ERANGE;
 128
 129         oobregion->offset = (section * 16) + 2;
 130         oobregion->length = 6;
 131
 132         return 0;
 133 }
 134
 135 static const struct mtd_ooblayout_ops micron_nand_on_die_4_ooblayout_ops = {
 136         .ecc = micron_nand_on_die_4_ooblayout_ecc,
 137         .free = micron_nand_on_die_4_ooblayout_free,
 138 };
 139
 140 static int micron_nand_on_die_8_ooblayout_ecc(struct mtd_info *mtd,
 141                                               int section,
 142                                               struct mtd_oob_region *oobregion)
 143 {
 144         struct nand_chip *chip = mtd_to_nand(mtd);
 145
 146         if (section)
 147                 return -ERANGE;
 148
 149         oobregion->offset = mtd->oobsize - chip->ecc.total;
 150         oobregion->length = chip->ecc.total;
 151
 152         return 0;
 153 }
 154
 155 static int micron_nand_on_die_8_ooblayout_free(struct mtd_info *mtd,
 156                                                int section,
 157                                                struct mtd_oob_region *oobregion)
 158 {
 159         struct nand_chip *chip = mtd_to_nand(mtd);
 160
 161         if (section)
 162                 return -ERANGE;
 163
 164         oobregion->offset = 2;
 165         oobregion->length = mtd->oobsize - chip->ecc.total - 2;
 166
 167         return 0;
 168 }
 169
 170 static const struct mtd_ooblayout_ops micron_nand_on_die_8_ooblayout_ops = {
 171         .ecc = micron_nand_on_die_8_ooblayout_ecc,
 172         .free = micron_nand_on_die_8_ooblayout_free,
 173 };
 174
 175 static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable)
 176 {
 177         struct micron_nand *micron = nand_get_manufacturer_data(chip);
 178         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 179         int ret;
 180
 181         if (micron->ecc.forced)
 182                 return 0;
 183
 184         if (micron->ecc.enabled == enable)
 185                 return 0;
 186
 187         if (enable)
 188                 feature[0] |= ONFI_FEATURE_ON_DIE_ECC_EN;
 189
 190         ret = nand_set_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 191         if (!ret)
 192                 micron->ecc.enabled = enable;
 193
 194         return ret;
 195 }
 196
 197 static int micron_nand_on_die_ecc_status_4(struct nand_chip *chip, u8 status,
 198                                            void *buf, int page,
 199                                            int oob_required)
 200 {
 201         struct micron_nand *micron = nand_get_manufacturer_data(chip);
 202         struct mtd_info *mtd = nand_to_mtd(chip);
 203         unsigned int step, max_bitflips = 0;
 204         int ret;
 205
 206         if (!(status & NAND_ECC_STATUS_WRITE_RECOMMENDED)) {
 207                 if (status & NAND_STATUS_FAIL)
 208                         mtd->ecc_stats.failed++;
 209
 210                 return 0;
 211         }
 212
 213         /*
 214          * The internal ECC doesn't tell us the number of bitflips that have
 215          * been corrected, but tells us if it recommends to rewrite the block.
 216          * If it's the case, we need to read the page in raw mode and compare
 217          * its content to the corrected version to extract the actual number of
 218          * bitflips.
 219          * But before we do that, we must make sure we have all OOB bytes read
 220          * in non-raw mode, even if the user did not request those bytes.
 221          */
 222         if (!oob_required) {
 223                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 224                                         false);
 225                 if (ret)
 226                         return ret;
 227         }
 228
 229         micron_nand_on_die_ecc_setup(chip, false);
 230
 231         ret = nand_read_page_op(chip, page, 0, micron->ecc.rawbuf,
 232                                 mtd->writesize + mtd->oobsize);
 233         if (ret)
 234                 return ret;
 235
 236         for (step = 0; step < chip->ecc.steps; step++) {
 237                 unsigned int offs, i, nbitflips = 0;
 238                 u8 *rawbuf, *corrbuf;
 239
 240                 offs = step * chip->ecc.size;
 241                 rawbuf = micron->ecc.rawbuf + offs;
 242                 corrbuf = buf + offs;
 243
 244                 for (i = 0; i < chip->ecc.size; i++)
 245                         nbitflips += hweight8(corrbuf[i] ^ rawbuf[i]);
 246
 247                 offs = (step * 16) + 4;
 248                 rawbuf = micron->ecc.rawbuf + mtd->writesize + offs;
 249                 corrbuf = chip->oob_poi + offs;
 250
 251                 for (i = 0; i < chip->ecc.bytes + 4; i++)
 252                         nbitflips += hweight8(corrbuf[i] ^ rawbuf[i]);
 253
 254                 if (WARN_ON(nbitflips > chip->ecc.strength))
 255                         return -EINVAL;
 256
 257                 max_bitflips = max(nbitflips, max_bitflips);
 258                 mtd->ecc_stats.corrected += nbitflips;
 259         }
 260
 261         return max_bitflips;
 262 }
 263
 264 static int micron_nand_on_die_ecc_status_8(struct nand_chip *chip, u8 status)
 265 {
 266         struct mtd_info *mtd = nand_to_mtd(chip);
 267
 268         /*
 269          * With 8/512 we have more information but still don't know precisely
 270          * how many bit-flips were seen.
 271          */
 272         switch (status & NAND_ECC_STATUS_MASK) {
 273         case NAND_ECC_STATUS_UNCORRECTABLE:
 274                 mtd->ecc_stats.failed++;
 275                 return 0;
 276         case NAND_ECC_STATUS_1_3_CORRECTED:
 277                 mtd->ecc_stats.corrected += 3;
 278                 return 3;
 279         case NAND_ECC_STATUS_4_6_CORRECTED:
 280                 mtd->ecc_stats.corrected += 6;
 281                 /* rewrite recommended */
 282                 return 6;
 283         case NAND_ECC_STATUS_7_8_CORRECTED:
 284                 mtd->ecc_stats.corrected += 8;
 285                 /* rewrite recommended */
 286                 return 8;
 287         default:
 288                 return 0;
 289         }
 290 }
 291
 292 static int
 293 micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 294                                  uint8_t *buf, int oob_required,
 295                                  int page)
 296 {
 297         u8 status;
 298         int ret, max_bitflips = 0;
 299
 300         ret = micron_nand_on_die_ecc_setup(chip, true);
 301         if (ret)
 302                 return ret;
 303
 304         ret = nand_read_page_op(chip, page, 0, NULL, 0);
 305         if (ret)
 306                 goto out;
 307
 308         ret = nand_status_op(chip, &status);
 309         if (ret)
 310                 goto out;
 311
 312         ret = nand_exit_status_op(chip);
 313         if (ret)
 314                 goto out;
 315
 316         ret = nand_read_data_op(chip, buf, mtd->writesize, false);
 317         if (!ret && oob_required)
 318                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 319                                         false);
 320
 321         if (chip->ecc.strength == 4)
 322                 max_bitflips = micron_nand_on_die_ecc_status_4(chip, status,
 323                                                                buf, page,
 324                                                                oob_required);
 325         else
 326                 max_bitflips = micron_nand_on_die_ecc_status_8(chip, status);
 327
 328 out:
 329         micron_nand_on_die_ecc_setup(chip, false);
 330
 331         return ret ? ret : max_bitflips;
 332 }
 333
 334 static int
 335 micron_nand_write_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 336                                   const uint8_t *buf, int oob_required,
 337                                   int page)
 338 {
 339         int ret;
 340
 341         ret = micron_nand_on_die_ecc_setup(chip, true);
 342         if (ret)
 343                 return ret;
 344
 345         ret = nand_write_page_raw(mtd, chip, buf, oob_required, page);
 346         micron_nand_on_die_ecc_setup(chip, false);
 347
 348         return ret;
 349 }
 350
 351 enum {
 352         /* The NAND flash doesn't support on-die ECC */
 353         MICRON_ON_DIE_UNSUPPORTED,
 354
 355         /*
 356          * The NAND flash supports on-die ECC and it can be
 357          * enabled/disabled by a set features command.
 358          */
 359         MICRON_ON_DIE_SUPPORTED,
 360
 361         /*
 362          * The NAND flash supports on-die ECC, and it cannot be
 363          * disabled.
 364          */
 365         MICRON_ON_DIE_MANDATORY,
 366 };
 367
 368 #define MICRON_ID_INTERNAL_ECC_MASK     GENMASK(1, 0)
 369 #define MICRON_ID_ECC_ENABLED           BIT(7)
 370
 371 /*
 372  * Try to detect if the NAND support on-die ECC. To do this, we enable
 373  * the feature, and read back if it has been enabled as expected. We
 374  * also check if it can be disabled, because some Micron NANDs do not
 375  * allow disabling the on-die ECC and we don't support such NANDs for
 376  * now.
 377  *
 378  * This function also has the side effect of disabling on-die ECC if
 379  * it had been left enabled by the firmware/bootloader.
 380  */
 381 static int micron_supports_on_die_ecc(struct nand_chip *chip)
 382 {
 383         u8 id[5];
 384         int ret;
 385
 386         if (!chip->parameters.onfi)
 387                 return MICRON_ON_DIE_UNSUPPORTED;
 388
 389         if (chip->bits_per_cell != 1)
 390                 return MICRON_ON_DIE_UNSUPPORTED;
 391
 392         /*
 393          * We only support on-die ECC of 4/512 or 8/512
 394          */
 395         if  (chip->ecc_strength_ds != 4 && chip->ecc_strength_ds != 8)
 396                 return MICRON_ON_DIE_UNSUPPORTED;
 397
 398         /* 0x2 means on-die ECC is available. */
 399         if (chip->id.len != 5 ||
 400             (chip->id.data[4] & MICRON_ID_INTERNAL_ECC_MASK) != 0x2)
 401                 return MICRON_ON_DIE_UNSUPPORTED;
 402
 403         /*
 404          * It seems that there are devices which do not support ECC officially.
 405          * At least the MT29F2G08ABAGA / MT29F2G08ABBGA devices supports
 406          * enabling the ECC feature but don't reflect that to the READ_ID table.
 407          * So we have to guarantee that we disable the ECC feature directly
 408          * after we did the READ_ID table command. Later we can evaluate the
 409          * ECC_ENABLE support.
 410          */
 411         ret = micron_nand_on_die_ecc_setup(chip, true);
 412         if (ret)
 413                 return MICRON_ON_DIE_UNSUPPORTED;
 414
 415         ret = nand_readid_op(chip, 0, id, sizeof(id));
 416         if (ret)
 417                 return MICRON_ON_DIE_UNSUPPORTED;
 418
 419         ret = micron_nand_on_die_ecc_setup(chip, false);
 420         if (ret)
 421                 return MICRON_ON_DIE_UNSUPPORTED;
 422
 423         if (!(id[4] & MICRON_ID_ECC_ENABLED))
 424                 return MICRON_ON_DIE_UNSUPPORTED;
 425
 426         ret = nand_readid_op(chip, 0, id, sizeof(id));
 427         if (ret)
 428                 return MICRON_ON_DIE_UNSUPPORTED;
 429
 430         if (id[4] & MICRON_ID_ECC_ENABLED)
 431                 return MICRON_ON_DIE_MANDATORY;
 432
 433         /*
 434          * We only support on-die ECC of 4/512 or 8/512
 435          */
 436         if  (chip->ecc_strength_ds != 4 && chip->ecc_strength_ds != 8)
 437                 return MICRON_ON_DIE_UNSUPPORTED;
 438
 439         return MICRON_ON_DIE_SUPPORTED;
 440 }
 441
 442 static int micron_nand_init(struct nand_chip *chip)
 443 {
 444         struct mtd_info *mtd = nand_to_mtd(chip);
 445         struct micron_nand *micron;
 446         int ondie;
 447         int ret;
 448
 449         micron = kzalloc(sizeof(*micron), GFP_KERNEL);
 450         if (!micron)
 451                 return -ENOMEM;
 452
 453         nand_set_manufacturer_data(chip, micron);
 454
 455         ret = micron_nand_onfi_init(chip);
 456         if (ret)
 457                 goto err_free_manuf_data;
 458
 459         if (mtd->writesize == 2048)
 460                 chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
 461
 462         ondie = micron_supports_on_die_ecc(chip);
 463
 464         if (ondie == MICRON_ON_DIE_MANDATORY &&
 465             chip->ecc.mode != NAND_ECC_ON_DIE) {
 466                 pr_err("On-die ECC forcefully enabled, not supported\n");
 467                 ret = -EINVAL;
 468                 goto err_free_manuf_data;
 469         }
 470
 471         if (chip->ecc.mode == NAND_ECC_ON_DIE) {
 472                 if (ondie == MICRON_ON_DIE_UNSUPPORTED) {
 473                         pr_err("On-die ECC selected but not supported\n");
 474                         ret = -EINVAL;
 475                         goto err_free_manuf_data;
 476                 }
 477
 478                 if (ondie == MICRON_ON_DIE_MANDATORY) {
 479                         micron->ecc.forced = true;
 480                         micron->ecc.enabled = true;
 481                 }
 482
 483                 /*
 484                  * In case of 4bit on-die ECC, we need a buffer to store a
 485                  * page dumped in raw mode so that we can compare its content
 486                  * to the same page after ECC correction happened and extract
 487                  * the real number of bitflips from this comparison.
 488                  * That's not needed for 8-bit ECC, because the status expose
 489                  * a better approximation of the number of bitflips in a page.
 490                  */
 491                 if (chip->ecc_strength_ds == 4) {
 492                         micron->ecc.rawbuf = kmalloc(mtd->writesize +
 493                                                      mtd->oobsize,
 494                                                      GFP_KERNEL);
 495                         if (!micron->ecc.rawbuf) {
 496                                 ret = -ENOMEM;
 497                                 goto err_free_manuf_data;
 498                         }
 499                 }
 500
 501                 if (chip->ecc_strength_ds == 4)
 502                         mtd_set_ooblayout(mtd,
 503                                           &micron_nand_on_die_4_ooblayout_ops);
 504                 else
 505                         mtd_set_ooblayout(mtd,
 506                                           &micron_nand_on_die_8_ooblayout_ops);
 507
 508                 chip->ecc.bytes = chip->ecc_strength_ds * 2;
 509                 chip->ecc.size = 512;
 510                 chip->ecc.strength = chip->ecc_strength_ds;
 511                 chip->ecc.algo = NAND_ECC_BCH;
 512                 chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
 513                 chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
 514
 515                 if (ondie == MICRON_ON_DIE_MANDATORY) {
 516                         chip->ecc.read_page_raw = nand_read_page_raw_notsupp;
 517                         chip->ecc.write_page_raw = nand_write_page_raw_notsupp;
 518                 } else {
 519                         chip->ecc.read_page_raw = nand_read_page_raw;
 520                         chip->ecc.write_page_raw = nand_write_page_raw;
 521                 }
 522         }
 523
 524         return 0;
 525
 526 err_free_manuf_data:
 527         kfree(micron->ecc.rawbuf);
 528         kfree(micron);
 529
 530         return ret;
 531 }
 532
 533 static void micron_nand_cleanup(struct nand_chip *chip)
 534 {
 535         struct micron_nand *micron = nand_get_manufacturer_data(chip);
 536
 537         kfree(micron->ecc.rawbuf);
 538         kfree(micron);
 539 }
 540
 541 static void micron_fixup_onfi_param_page(struct nand_chip *chip,
 542                                          struct nand_onfi_params *p)
 543 {
 544         /*
 545          * MT29F1G08ABAFAWP-ITE:F and possibly others report 00 00 for the
 546          * revision number field of the ONFI parameter page. Assume ONFI
 547          * version 1.0 if the revision number is 00 00.
 548          */
 549         if (le16_to_cpu(p->revision) == 0)
 550                 p->revision = cpu_to_le16(ONFI_VERSION_1_0);
 551 }
 552
 553 const struct nand_manufacturer_ops micron_nand_manuf_ops = {
 554         .init = micron_nand_init,
 555         .cleanup = micron_nand_cleanup,
 556         .fixup_onfi_param_page = micron_fixup_onfi_param_page,
 557 };