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
  20 /*
  21  * Special Micron status bit that indicates when the block has been
  22  * corrected by on-die ECC and should be rewritten
  23  */
  24 #define NAND_STATUS_WRITE_RECOMMENDED   BIT(3)
  25
  26 struct nand_onfi_vendor_micron {
  27         u8 two_plane_read;
  28         u8 read_cache;
  29         u8 read_unique_id;
  30         u8 dq_imped;
  31         u8 dq_imped_num_settings;
  32         u8 dq_imped_feat_addr;
  33         u8 rb_pulldown_strength;
  34         u8 rb_pulldown_strength_feat_addr;
  35         u8 rb_pulldown_strength_num_settings;
  36         u8 otp_mode;
  37         u8 otp_page_start;
  38         u8 otp_data_prot_addr;
  39         u8 otp_num_pages;
  40         u8 otp_feat_addr;
  41         u8 read_retry_options;
  42         u8 reserved[72];
  43         u8 param_revision;
  44 } __packed;
  45
  46 static int micron_nand_setup_read_retry(struct mtd_info *mtd, int retry_mode)
  47 {
  48         struct nand_chip *chip = mtd_to_nand(mtd);
  49         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = {retry_mode};
  50
  51         return nand_set_features(chip, ONFI_FEATURE_ADDR_READ_RETRY, feature);
  52 }
  53
  54 /*
  55  * Configure chip properties from Micron vendor-specific ONFI table
  56  */
  57 static int micron_nand_onfi_init(struct nand_chip *chip)
  58 {
  59         struct nand_parameters *p = &chip->parameters;
  60         struct nand_onfi_vendor_micron *micron = (void *)p->onfi.vendor;
  61
  62         if (chip->parameters.onfi.version && p->onfi.vendor_revision) {
  63                 chip->read_retries = micron->read_retry_options;
  64                 chip->setup_read_retry = micron_nand_setup_read_retry;
  65         }
  66
  67         if (p->supports_set_get_features) {
  68                 set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->set_feature_list);
  69                 set_bit(ONFI_FEATURE_ON_DIE_ECC, p->set_feature_list);
  70                 set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->get_feature_list);
  71                 set_bit(ONFI_FEATURE_ON_DIE_ECC, p->get_feature_list);
  72         }
  73
  74         return 0;
  75 }
  76
  77 static int micron_nand_on_die_ooblayout_ecc(struct mtd_info *mtd, int section,
  78                                             struct mtd_oob_region *oobregion)
  79 {
  80         if (section >= 4)
  81                 return -ERANGE;
  82
  83         oobregion->offset = (section * 16) + 8;
  84         oobregion->length = 8;
  85
  86         return 0;
  87 }
  88
  89 static int micron_nand_on_die_ooblayout_free(struct mtd_info *mtd, int section,
  90                                              struct mtd_oob_region *oobregion)
  91 {
  92         if (section >= 4)
  93                 return -ERANGE;
  94
  95         oobregion->offset = (section * 16) + 2;
  96         oobregion->length = 6;
  97
  98         return 0;
  99 }
 100
 101 static const struct mtd_ooblayout_ops micron_nand_on_die_ooblayout_ops = {
 102         .ecc = micron_nand_on_die_ooblayout_ecc,
 103         .free = micron_nand_on_die_ooblayout_free,
 104 };
 105
 106 static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable)
 107 {
 108         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 109
 110         if (enable)
 111                 feature[0] |= ONFI_FEATURE_ON_DIE_ECC_EN;
 112
 113         return nand_set_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 114 }
 115
 116 static int
 117 micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 118                                  uint8_t *buf, int oob_required,
 119                                  int page)
 120 {
 121         u8 status;
 122         int ret, max_bitflips = 0;
 123
 124         ret = micron_nand_on_die_ecc_setup(chip, true);
 125         if (ret)
 126                 return ret;
 127
 128         ret = nand_read_page_op(chip, page, 0, NULL, 0);
 129         if (ret)
 130                 goto out;
 131
 132         ret = nand_status_op(chip, &status);
 133         if (ret)
 134                 goto out;
 135
 136         ret = nand_exit_status_op(chip);
 137         if (ret)
 138                 goto out;
 139
 140         if (status & NAND_STATUS_FAIL)
 141                 mtd->ecc_stats.failed++;
 142
 143         /*
 144          * The internal ECC doesn't tell us the number of bitflips
 145          * that have been corrected, but tells us if it recommends to
 146          * rewrite the block. If it's the case, then we pretend we had
 147          * a number of bitflips equal to the ECC strength, which will
 148          * hint the NAND core to rewrite the block.
 149          */
 150         else if (status & NAND_STATUS_WRITE_RECOMMENDED)
 151                 max_bitflips = chip->ecc.strength;
 152
 153         ret = nand_read_data_op(chip, buf, mtd->writesize, false);
 154         if (!ret && oob_required)
 155                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 156                                         false);
 157
 158 out:
 159         micron_nand_on_die_ecc_setup(chip, false);
 160
 161         return ret ? ret : max_bitflips;
 162 }
 163
 164 static int
 165 micron_nand_write_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 166                                   const uint8_t *buf, int oob_required,
 167                                   int page)
 168 {
 169         int ret;
 170
 171         ret = micron_nand_on_die_ecc_setup(chip, true);
 172         if (ret)
 173                 return ret;
 174
 175         ret = nand_write_page_raw(mtd, chip, buf, oob_required, page);
 176         micron_nand_on_die_ecc_setup(chip, false);
 177
 178         return ret;
 179 }
 180
 181 enum {
 182         /* The NAND flash doesn't support on-die ECC */
 183         MICRON_ON_DIE_UNSUPPORTED,
 184
 185         /*
 186          * The NAND flash supports on-die ECC and it can be
 187          * enabled/disabled by a set features command.
 188          */
 189         MICRON_ON_DIE_SUPPORTED,
 190
 191         /*
 192          * The NAND flash supports on-die ECC, and it cannot be
 193          * disabled.
 194          */
 195         MICRON_ON_DIE_MANDATORY,
 196 };
 197
 198 /*
 199  * Try to detect if the NAND support on-die ECC. To do this, we enable
 200  * the feature, and read back if it has been enabled as expected. We
 201  * also check if it can be disabled, because some Micron NANDs do not
 202  * allow disabling the on-die ECC and we don't support such NANDs for
 203  * now.
 204  *
 205  * This function also has the side effect of disabling on-die ECC if
 206  * it had been left enabled by the firmware/bootloader.
 207  */
 208 static int micron_supports_on_die_ecc(struct nand_chip *chip)
 209 {
 210         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 211         int ret;
 212
 213         if (!chip->parameters.onfi.version)
 214                 return MICRON_ON_DIE_UNSUPPORTED;
 215
 216         if (chip->bits_per_cell != 1)
 217                 return MICRON_ON_DIE_UNSUPPORTED;
 218
 219         ret = micron_nand_on_die_ecc_setup(chip, true);
 220         if (ret)
 221                 return MICRON_ON_DIE_UNSUPPORTED;
 222
 223         ret = nand_get_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 224         if (ret < 0)
 225                 return ret;
 226
 227         if ((feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN) == 0)
 228                 return MICRON_ON_DIE_UNSUPPORTED;
 229
 230         ret = micron_nand_on_die_ecc_setup(chip, false);
 231         if (ret)
 232                 return MICRON_ON_DIE_UNSUPPORTED;
 233
 234         ret = nand_get_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 235         if (ret < 0)
 236                 return ret;
 237
 238         if (feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN)
 239                 return MICRON_ON_DIE_MANDATORY;
 240
 241         /*
 242          * Some Micron NANDs have an on-die ECC of 4/512, some other
 243          * 8/512. We only support the former.
 244          */
 245         if (chip->ecc_strength_ds != 4)
 246                 return MICRON_ON_DIE_UNSUPPORTED;
 247
 248         return MICRON_ON_DIE_SUPPORTED;
 249 }
 250
 251 static int micron_nand_init(struct nand_chip *chip)
 252 {
 253         struct mtd_info *mtd = nand_to_mtd(chip);
 254         int ondie;
 255         int ret;
 256
 257         ret = micron_nand_onfi_init(chip);
 258         if (ret)
 259                 return ret;
 260
 261         if (mtd->writesize == 2048)
 262                 chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
 263
 264         ondie = micron_supports_on_die_ecc(chip);
 265
 266         if (ondie == MICRON_ON_DIE_MANDATORY) {
 267                 pr_err("On-die ECC forcefully enabled, not supported\n");
 268                 return -EINVAL;
 269         }
 270
 271         if (chip->ecc.mode == NAND_ECC_ON_DIE) {
 272                 if (ondie == MICRON_ON_DIE_UNSUPPORTED) {
 273                         pr_err("On-die ECC selected but not supported\n");
 274                         return -EINVAL;
 275                 }
 276
 277                 chip->ecc.bytes = 8;
 278                 chip->ecc.size = 512;
 279                 chip->ecc.strength = 4;
 280                 chip->ecc.algo = NAND_ECC_BCH;
 281                 chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
 282                 chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
 283                 chip->ecc.read_page_raw = nand_read_page_raw;
 284                 chip->ecc.write_page_raw = nand_write_page_raw;
 285
 286                 mtd_set_ooblayout(mtd, &micron_nand_on_die_ooblayout_ops);
 287         }
 288
 289         return 0;
 290 }
 291
 292 const struct nand_manufacturer_ops micron_nand_manuf_ops = {
 293         .init = micron_nand_init,
 294 };