drivers/mtd/nand/raw/nand_micron.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2017 Free Electrons
   4  * Copyright (C) 2017 NextThing Co
   5  *
   6  * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
   7  */
   8
   9 #include <linux/slab.h>
  10
  11 #include "internals.h"
  12
  13 /*
  14  * Special Micron status bit 3 indicates that the block has been
  15  * corrected by on-die ECC and should be rewritten.
  16  */
  17 #define NAND_ECC_STATUS_WRITE_RECOMMENDED       BIT(3)
  18
  19 /*
  20  * On chips with 8-bit ECC and additional bit can be used to distinguish
  21  * cases where a errors were corrected without needing a rewrite
  22  *
  23  * Bit 4 Bit 3 Bit 0 Description
  24  * ----- ----- ----- -----------
  25  * 0     0     0     No Errors
  26  * 0     0     1     Multiple uncorrected errors
  27  * 0     1     0     4 - 6 errors corrected, recommend rewrite
  28  * 0     1     1     Reserved
  29  * 1     0     0     1 - 3 errors corrected
  30  * 1     0     1     Reserved
  31  * 1     1     0     7 - 8 errors corrected, recommend rewrite
  32  */
  33 #define NAND_ECC_STATUS_MASK            (BIT(4) | BIT(3) | BIT(0))
  34 #define NAND_ECC_STATUS_UNCORRECTABLE   BIT(0)
  35 #define NAND_ECC_STATUS_4_6_CORRECTED   BIT(3)
  36 #define NAND_ECC_STATUS_1_3_CORRECTED   BIT(4)
  37 #define NAND_ECC_STATUS_7_8_CORRECTED   (BIT(4) | BIT(3))
  38
  39 struct nand_onfi_vendor_micron {
  40         u8 two_plane_read;
  41         u8 read_cache;
  42         u8 read_unique_id;
  43         u8 dq_imped;
  44         u8 dq_imped_num_settings;
  45         u8 dq_imped_feat_addr;
  46         u8 rb_pulldown_strength;
  47         u8 rb_pulldown_strength_feat_addr;
  48         u8 rb_pulldown_strength_num_settings;
  49         u8 otp_mode;
  50         u8 otp_page_start;
  51         u8 otp_data_prot_addr;
  52         u8 otp_num_pages;
  53         u8 otp_feat_addr;
  54         u8 read_retry_options;
  55         u8 reserved[72];
  56         u8 param_revision;
  57 } __packed;
  58
  59 struct micron_on_die_ecc {
  60         bool forced;
  61         bool enabled;
  62         void *rawbuf;
  63 };
  64
  65 struct micron_nand {
  66         struct micron_on_die_ecc ecc;
  67 };
  68
  69 static int micron_nand_setup_read_retry(struct nand_chip *chip, int retry_mode)
  70 {
  71         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = {retry_mode};
  72
  73         return nand_set_features(chip, ONFI_FEATURE_ADDR_READ_RETRY, feature);
  74 }
  75
  76 /*
  77  * Configure chip properties from Micron vendor-specific ONFI table
  78  */
  79 static int micron_nand_onfi_init(struct nand_chip *chip)
  80 {
  81         struct nand_parameters *p = &chip->parameters;
  82
  83         if (p->onfi) {
  84                 struct nand_onfi_vendor_micron *micron = (void *)p->onfi->vendor;
  85
  86                 chip->read_retries = micron->read_retry_options;
  87                 chip->setup_read_retry = micron_nand_setup_read_retry;
  88         }
  89
  90         if (p->supports_set_get_features) {
  91                 set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->set_feature_list);
  92                 set_bit(ONFI_FEATURE_ON_DIE_ECC, p->set_feature_list);
  93                 set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->get_feature_list);
  94                 set_bit(ONFI_FEATURE_ON_DIE_ECC, p->get_feature_list);
  95         }
  96
  97         return 0;
  98 }
  99
 100 static int micron_nand_on_die_4_ooblayout_ecc(struct mtd_info *mtd,
 101                                               int section,
 102                                               struct mtd_oob_region *oobregion)
 103 {
 104         if (section >= 4)
 105                 return -ERANGE;
 106
 107         oobregion->offset = (section * 16) + 8;
 108         oobregion->length = 8;
 109
 110         return 0;
 111 }
 112
 113 static int micron_nand_on_die_4_ooblayout_free(struct mtd_info *mtd,
 114                                                int section,
 115                                                struct mtd_oob_region *oobregion)
 116 {
 117         if (section >= 4)
 118                 return -ERANGE;
 119
 120         oobregion->offset = (section * 16) + 2;
 121         oobregion->length = 6;
 122
 123         return 0;
 124 }
 125
 126 static const struct mtd_ooblayout_ops micron_nand_on_die_4_ooblayout_ops = {
 127         .ecc = micron_nand_on_die_4_ooblayout_ecc,
 128         .free = micron_nand_on_die_4_ooblayout_free,
 129 };
 130
 131 static int micron_nand_on_die_8_ooblayout_ecc(struct mtd_info *mtd,
 132                                               int section,
 133                                               struct mtd_oob_region *oobregion)
 134 {
 135         struct nand_chip *chip = mtd_to_nand(mtd);
 136
 137         if (section)
 138                 return -ERANGE;
 139
 140         oobregion->offset = mtd->oobsize - chip->ecc.total;
 141         oobregion->length = chip->ecc.total;
 142
 143         return 0;
 144 }
 145
 146 static int micron_nand_on_die_8_ooblayout_free(struct mtd_info *mtd,
 147                                                int section,
 148                                                struct mtd_oob_region *oobregion)
 149 {
 150         struct nand_chip *chip = mtd_to_nand(mtd);
 151
 152         if (section)
 153                 return -ERANGE;
 154
 155         oobregion->offset = 2;
 156         oobregion->length = mtd->oobsize - chip->ecc.total - 2;
 157
 158         return 0;
 159 }
 160
 161 static const struct mtd_ooblayout_ops micron_nand_on_die_8_ooblayout_ops = {
 162         .ecc = micron_nand_on_die_8_ooblayout_ecc,
 163         .free = micron_nand_on_die_8_ooblayout_free,
 164 };
 165
 166 static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable)
 167 {
 168         struct micron_nand *micron = nand_get_manufacturer_data(chip);
 169         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 170         int ret;
 171
 172         if (micron->ecc.forced)
 173                 return 0;
 174
 175         if (micron->ecc.enabled == enable)
 176                 return 0;
 177
 178         if (enable)
 179                 feature[0] |= ONFI_FEATURE_ON_DIE_ECC_EN;
 180
 181         ret = nand_set_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 182         if (!ret)
 183                 micron->ecc.enabled = enable;
 184
 185         return ret;
 186 }
 187
 188 static int micron_nand_on_die_ecc_status_4(struct nand_chip *chip, u8 status,
 189                                            void *buf, int page,
 190                                            int oob_required)
 191 {
 192         struct micron_nand *micron = nand_get_manufacturer_data(chip);
 193         struct mtd_info *mtd = nand_to_mtd(chip);
 194         unsigned int step, max_bitflips = 0;
 195         int ret;
 196
 197         if (!(status & NAND_ECC_STATUS_WRITE_RECOMMENDED)) {
 198                 if (status & NAND_STATUS_FAIL)
 199                         mtd->ecc_stats.failed++;
 200
 201                 return 0;
 202         }
 203
 204         /*
 205          * The internal ECC doesn't tell us the number of bitflips that have
 206          * been corrected, but tells us if it recommends to rewrite the block.
 207          * If it's the case, we need to read the page in raw mode and compare
 208          * its content to the corrected version to extract the actual number of
 209          * bitflips.
 210          * But before we do that, we must make sure we have all OOB bytes read
 211          * in non-raw mode, even if the user did not request those bytes.
 212          */
 213         if (!oob_required) {
 214                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 215                                         false);
 216                 if (ret)
 217                         return ret;
 218         }
 219
 220         micron_nand_on_die_ecc_setup(chip, false);
 221
 222         ret = nand_read_page_op(chip, page, 0, micron->ecc.rawbuf,
 223                                 mtd->writesize + mtd->oobsize);
 224         if (ret)
 225                 return ret;
 226
 227         for (step = 0; step < chip->ecc.steps; step++) {
 228                 unsigned int offs, i, nbitflips = 0;
 229                 u8 *rawbuf, *corrbuf;
 230
 231                 offs = step * chip->ecc.size;
 232                 rawbuf = micron->ecc.rawbuf + offs;
 233                 corrbuf = buf + offs;
 234
 235                 for (i = 0; i < chip->ecc.size; i++)
 236                         nbitflips += hweight8(corrbuf[i] ^ rawbuf[i]);
 237
 238                 offs = (step * 16) + 4;
 239                 rawbuf = micron->ecc.rawbuf + mtd->writesize + offs;
 240                 corrbuf = chip->oob_poi + offs;
 241
 242                 for (i = 0; i < chip->ecc.bytes + 4; i++)
 243                         nbitflips += hweight8(corrbuf[i] ^ rawbuf[i]);
 244
 245                 if (WARN_ON(nbitflips > chip->ecc.strength))
 246                         return -EINVAL;
 247
 248                 max_bitflips = max(nbitflips, max_bitflips);
 249                 mtd->ecc_stats.corrected += nbitflips;
 250         }
 251
 252         return max_bitflips;
 253 }
 254
 255 static int micron_nand_on_die_ecc_status_8(struct nand_chip *chip, u8 status)
 256 {
 257         struct mtd_info *mtd = nand_to_mtd(chip);
 258
 259         /*
 260          * With 8/512 we have more information but still don't know precisely
 261          * how many bit-flips were seen.
 262          */
 263         switch (status & NAND_ECC_STATUS_MASK) {
 264         case NAND_ECC_STATUS_UNCORRECTABLE:
 265                 mtd->ecc_stats.failed++;
 266                 return 0;
 267         case NAND_ECC_STATUS_1_3_CORRECTED:
 268                 mtd->ecc_stats.corrected += 3;
 269                 return 3;
 270         case NAND_ECC_STATUS_4_6_CORRECTED:
 271                 mtd->ecc_stats.corrected += 6;
 272                 /* rewrite recommended */
 273                 return 6;
 274         case NAND_ECC_STATUS_7_8_CORRECTED:
 275                 mtd->ecc_stats.corrected += 8;
 276                 /* rewrite recommended */
 277                 return 8;
 278         default:
 279                 return 0;
 280         }
 281 }
 282
 283 static int
 284 micron_nand_read_page_on_die_ecc(struct nand_chip *chip, uint8_t *buf,
 285                                  int oob_required, int page)
 286 {
 287         struct mtd_info *mtd = nand_to_mtd(chip);
 288         u8 status;
 289         int ret, max_bitflips = 0;
 290
 291         ret = micron_nand_on_die_ecc_setup(chip, true);
 292         if (ret)
 293                 return ret;
 294
 295         ret = nand_read_page_op(chip, page, 0, NULL, 0);
 296         if (ret)
 297                 goto out;
 298
 299         ret = nand_status_op(chip, &status);
 300         if (ret)
 301                 goto out;
 302
 303         ret = nand_exit_status_op(chip);
 304         if (ret)
 305                 goto out;
 306
 307         ret = nand_read_data_op(chip, buf, mtd->writesize, false);
 308         if (!ret && oob_required)
 309                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 310                                         false);
 311
 312         if (chip->ecc.strength == 4)
 313                 max_bitflips = micron_nand_on_die_ecc_status_4(chip, status,
 314                                                                buf, page,
 315                                                                oob_required);
 316         else
 317                 max_bitflips = micron_nand_on_die_ecc_status_8(chip, status);
 318
 319 out:
 320         micron_nand_on_die_ecc_setup(chip, false);
 321
 322         return ret ? ret : max_bitflips;
 323 }
 324
 325 static int
 326 micron_nand_write_page_on_die_ecc(struct nand_chip *chip, const uint8_t *buf,
 327                                   int oob_required, int page)
 328 {
 329         int ret;
 330
 331         ret = micron_nand_on_die_ecc_setup(chip, true);
 332         if (ret)
 333                 return ret;
 334
 335         ret = nand_write_page_raw(chip, buf, oob_required, page);
 336         micron_nand_on_die_ecc_setup(chip, false);
 337
 338         return ret;
 339 }
 340
 341 enum {
 342         /* The NAND flash doesn't support on-die ECC */
 343         MICRON_ON_DIE_UNSUPPORTED,
 344
 345         /*
 346          * The NAND flash supports on-die ECC and it can be
 347          * enabled/disabled by a set features command.
 348          */
 349         MICRON_ON_DIE_SUPPORTED,
 350
 351         /*
 352          * The NAND flash supports on-die ECC, and it cannot be
 353          * disabled.
 354          */
 355         MICRON_ON_DIE_MANDATORY,
 356 };
 357
 358 #define MICRON_ID_INTERNAL_ECC_MASK     GENMASK(1, 0)
 359 #define MICRON_ID_ECC_ENABLED           BIT(7)
 360
 361 /*
 362  * Try to detect if the NAND support on-die ECC. To do this, we enable
 363  * the feature, and read back if it has been enabled as expected. We
 364  * also check if it can be disabled, because some Micron NANDs do not
 365  * allow disabling the on-die ECC and we don't support such NANDs for
 366  * now.
 367  *
 368  * This function also has the side effect of disabling on-die ECC if
 369  * it had been left enabled by the firmware/bootloader.
 370  */
 371 static int micron_supports_on_die_ecc(struct nand_chip *chip)
 372 {
 373         u8 id[5];
 374         int ret;
 375
 376         if (!chip->parameters.onfi)
 377                 return MICRON_ON_DIE_UNSUPPORTED;
 378
 379         if (nanddev_bits_per_cell(&chip->base) != 1)
 380                 return MICRON_ON_DIE_UNSUPPORTED;
 381
 382         /*
 383          * We only support on-die ECC of 4/512 or 8/512
 384          */
 385         if  (chip->base.eccreq.strength != 4 && chip->base.eccreq.strength != 8)
 386                 return MICRON_ON_DIE_UNSUPPORTED;
 387
 388         /* 0x2 means on-die ECC is available. */
 389         if (chip->id.len != 5 ||
 390             (chip->id.data[4] & MICRON_ID_INTERNAL_ECC_MASK) != 0x2)
 391                 return MICRON_ON_DIE_UNSUPPORTED;
 392
 393         ret = micron_nand_on_die_ecc_setup(chip, true);
 394         if (ret)
 395                 return MICRON_ON_DIE_UNSUPPORTED;
 396
 397         ret = nand_readid_op(chip, 0, id, sizeof(id));
 398         if (ret)
 399                 return MICRON_ON_DIE_UNSUPPORTED;
 400
 401         if (!(id[4] & MICRON_ID_ECC_ENABLED))
 402                 return MICRON_ON_DIE_UNSUPPORTED;
 403
 404         ret = micron_nand_on_die_ecc_setup(chip, false);
 405         if (ret)
 406                 return MICRON_ON_DIE_UNSUPPORTED;
 407
 408         ret = nand_readid_op(chip, 0, id, sizeof(id));
 409         if (ret)
 410                 return MICRON_ON_DIE_UNSUPPORTED;
 411
 412         if (id[4] & MICRON_ID_ECC_ENABLED)
 413                 return MICRON_ON_DIE_MANDATORY;
 414
 415         /*
 416          * We only support on-die ECC of 4/512 or 8/512
 417          */
 418         if  (chip->base.eccreq.strength != 4 && chip->base.eccreq.strength != 8)
 419                 return MICRON_ON_DIE_UNSUPPORTED;
 420
 421         return MICRON_ON_DIE_SUPPORTED;
 422 }
 423
 424 static int micron_nand_init(struct nand_chip *chip)
 425 {
 426         struct mtd_info *mtd = nand_to_mtd(chip);
 427         struct micron_nand *micron;
 428         int ondie;
 429         int ret;
 430
 431         micron = kzalloc(sizeof(*micron), GFP_KERNEL);
 432         if (!micron)
 433                 return -ENOMEM;
 434
 435         nand_set_manufacturer_data(chip, micron);
 436
 437         ret = micron_nand_onfi_init(chip);
 438         if (ret)
 439                 goto err_free_manuf_data;
 440
 441         if (mtd->writesize == 2048)
 442                 chip->options |= NAND_BBM_FIRSTPAGE | NAND_BBM_SECONDPAGE;
 443
 444         ondie = micron_supports_on_die_ecc(chip);
 445
 446         if (ondie == MICRON_ON_DIE_MANDATORY &&
 447             chip->ecc.mode != NAND_ECC_ON_DIE) {
 448                 pr_err("On-die ECC forcefully enabled, not supported\n");
 449                 ret = -EINVAL;
 450                 goto err_free_manuf_data;
 451         }
 452
 453         if (chip->ecc.mode == NAND_ECC_ON_DIE) {
 454                 if (ondie == MICRON_ON_DIE_UNSUPPORTED) {
 455                         pr_err("On-die ECC selected but not supported\n");
 456                         ret = -EINVAL;
 457                         goto err_free_manuf_data;
 458                 }
 459
 460                 if (ondie == MICRON_ON_DIE_MANDATORY) {
 461                         micron->ecc.forced = true;
 462                         micron->ecc.enabled = true;
 463                 }
 464
 465                 /*
 466                  * In case of 4bit on-die ECC, we need a buffer to store a
 467                  * page dumped in raw mode so that we can compare its content
 468                  * to the same page after ECC correction happened and extract
 469                  * the real number of bitflips from this comparison.
 470                  * That's not needed for 8-bit ECC, because the status expose
 471                  * a better approximation of the number of bitflips in a page.
 472                  */
 473                 if (chip->base.eccreq.strength == 4) {
 474                         micron->ecc.rawbuf = kmalloc(mtd->writesize +
 475                                                      mtd->oobsize,
 476                                                      GFP_KERNEL);
 477                         if (!micron->ecc.rawbuf) {
 478                                 ret = -ENOMEM;
 479                                 goto err_free_manuf_data;
 480                         }
 481                 }
 482
 483                 if (chip->base.eccreq.strength == 4)
 484                         mtd_set_ooblayout(mtd,
 485                                           &micron_nand_on_die_4_ooblayout_ops);
 486                 else
 487                         mtd_set_ooblayout(mtd,
 488                                           &micron_nand_on_die_8_ooblayout_ops);
 489
 490                 chip->ecc.bytes = chip->base.eccreq.strength * 2;
 491                 chip->ecc.size = 512;
 492                 chip->ecc.strength = chip->base.eccreq.strength;
 493                 chip->ecc.algo = NAND_ECC_BCH;
 494                 chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
 495                 chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
 496
 497                 if (ondie == MICRON_ON_DIE_MANDATORY) {
 498                         chip->ecc.read_page_raw = nand_read_page_raw_notsupp;
 499                         chip->ecc.write_page_raw = nand_write_page_raw_notsupp;
 500                 } else {
 501                         chip->ecc.read_page_raw = nand_read_page_raw;
 502                         chip->ecc.write_page_raw = nand_write_page_raw;
 503                 }
 504         }
 505
 506         return 0;
 507
 508 err_free_manuf_data:
 509         kfree(micron->ecc.rawbuf);
 510         kfree(micron);
 511
 512         return ret;
 513 }
 514
 515 static void micron_nand_cleanup(struct nand_chip *chip)
 516 {
 517         struct micron_nand *micron = nand_get_manufacturer_data(chip);
 518
 519         kfree(micron->ecc.rawbuf);
 520         kfree(micron);
 521 }
 522
 523 static void micron_fixup_onfi_param_page(struct nand_chip *chip,
 524                                          struct nand_onfi_params *p)
 525 {
 526         /*
 527          * MT29F1G08ABAFAWP-ITE:F and possibly others report 00 00 for the
 528          * revision number field of the ONFI parameter page. Assume ONFI
 529          * version 1.0 if the revision number is 00 00.
 530          */
 531         if (le16_to_cpu(p->revision) == 0)
 532                 p->revision = cpu_to_le16(ONFI_VERSION_1_0);
 533 }
 534
 535 const struct nand_manufacturer_ops micron_nand_manuf_ops = {
 536         .init = micron_nand_init,
 537         .cleanup = micron_nand_cleanup,
 538         .fixup_onfi_param_page = micron_fixup_onfi_param_page,
 539 };