drivers/mtd/nand/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 chip->onfi_set_features(mtd, chip, ONFI_FEATURE_ADDR_READ_RETRY,
  52                                        feature);
  53 }
  54
  55 /*
  56  * Configure chip properties from Micron vendor-specific ONFI table
  57  */
  58 static int micron_nand_onfi_init(struct nand_chip *chip)
  59 {
  60         struct nand_onfi_params *p = &chip->onfi_params;
  61         struct nand_onfi_vendor_micron *micron = (void *)p->vendor;
  62
  63         if (!chip->onfi_version)
  64                 return 0;
  65
  66         if (le16_to_cpu(p->vendor_revision) < 1)
  67                 return 0;
  68
  69         chip->read_retries = micron->read_retry_options;
  70         chip->setup_read_retry = micron_nand_setup_read_retry;
  71
  72         return 0;
  73 }
  74
  75 static int micron_nand_on_die_ooblayout_ecc(struct mtd_info *mtd, int section,
  76                                             struct mtd_oob_region *oobregion)
  77 {
  78         if (section >= 4)
  79                 return -ERANGE;
  80
  81         oobregion->offset = (section * 16) + 8;
  82         oobregion->length = 8;
  83
  84         return 0;
  85 }
  86
  87 static int micron_nand_on_die_ooblayout_free(struct mtd_info *mtd, int section,
  88                                              struct mtd_oob_region *oobregion)
  89 {
  90         if (section >= 4)
  91                 return -ERANGE;
  92
  93         oobregion->offset = (section * 16) + 2;
  94         oobregion->length = 6;
  95
  96         return 0;
  97 }
  98
  99 static const struct mtd_ooblayout_ops micron_nand_on_die_ooblayout_ops = {
 100         .ecc = micron_nand_on_die_ooblayout_ecc,
 101         .free = micron_nand_on_die_ooblayout_free,
 102 };
 103
 104 static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable)
 105 {
 106         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 107
 108         if (enable)
 109                 feature[0] |= ONFI_FEATURE_ON_DIE_ECC_EN;
 110
 111         return chip->onfi_set_features(nand_to_mtd(chip), chip,
 112                                        ONFI_FEATURE_ON_DIE_ECC, feature);
 113 }
 114
 115 static int
 116 micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 117                                  uint8_t *buf, int oob_required,
 118                                  int page)
 119 {
 120         u8 status;
 121         int ret, max_bitflips = 0;
 122
 123         ret = micron_nand_on_die_ecc_setup(chip, true);
 124         if (ret)
 125                 return ret;
 126
 127         ret = nand_read_page_op(chip, page, 0, NULL, 0);
 128         if (ret)
 129                 goto out;
 130
 131         ret = nand_status_op(chip, &status);
 132         if (ret)
 133                 goto out;
 134
 135         ret = nand_exit_status_op(chip);
 136         if (ret)
 137                 goto out;
 138
 139         if (status & NAND_STATUS_FAIL)
 140                 mtd->ecc_stats.failed++;
 141
 142         /*
 143          * The internal ECC doesn't tell us the number of bitflips
 144          * that have been corrected, but tells us if it recommends to
 145          * rewrite the block. If it's the case, then we pretend we had
 146          * a number of bitflips equal to the ECC strength, which will
 147          * hint the NAND core to rewrite the block.
 148          */
 149         else if (status & NAND_STATUS_WRITE_RECOMMENDED)
 150                 max_bitflips = chip->ecc.strength;
 151
 152         ret = nand_read_data_op(chip, buf, mtd->writesize, false);
 153         if (!ret && oob_required)
 154                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 155                                         false);
 156
 157 out:
 158         micron_nand_on_die_ecc_setup(chip, false);
 159
 160         return ret ? ret : max_bitflips;
 161 }
 162
 163 static int
 164 micron_nand_write_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 165                                   const uint8_t *buf, int oob_required,
 166                                   int page)
 167 {
 168         int ret;
 169
 170         ret = micron_nand_on_die_ecc_setup(chip, true);
 171         if (ret)
 172                 return ret;
 173
 174         ret = nand_write_page_raw(mtd, chip, buf, oob_required, page);
 175         micron_nand_on_die_ecc_setup(chip, false);
 176
 177         return ret;
 178 }
 179
 180 enum {
 181         /* The NAND flash doesn't support on-die ECC */
 182         MICRON_ON_DIE_UNSUPPORTED,
 183
 184         /*
 185          * The NAND flash supports on-die ECC and it can be
 186          * enabled/disabled by a set features command.
 187          */
 188         MICRON_ON_DIE_SUPPORTED,
 189
 190         /*
 191          * The NAND flash supports on-die ECC, and it cannot be
 192          * disabled.
 193          */
 194         MICRON_ON_DIE_MANDATORY,
 195 };
 196
 197 /*
 198  * Try to detect if the NAND support on-die ECC. To do this, we enable
 199  * the feature, and read back if it has been enabled as expected. We
 200  * also check if it can be disabled, because some Micron NANDs do not
 201  * allow disabling the on-die ECC and we don't support such NANDs for
 202  * now.
 203  *
 204  * This function also has the side effect of disabling on-die ECC if
 205  * it had been left enabled by the firmware/bootloader.
 206  */
 207 static int micron_supports_on_die_ecc(struct nand_chip *chip)
 208 {
 209         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 210         int ret;
 211
 212         if (chip->onfi_version == 0)
 213                 return MICRON_ON_DIE_UNSUPPORTED;
 214
 215         if (chip->bits_per_cell != 1)
 216                 return MICRON_ON_DIE_UNSUPPORTED;
 217
 218         ret = micron_nand_on_die_ecc_setup(chip, true);
 219         if (ret)
 220                 return MICRON_ON_DIE_UNSUPPORTED;
 221
 222         chip->onfi_get_features(nand_to_mtd(chip), chip,
 223                                 ONFI_FEATURE_ON_DIE_ECC, feature);
 224         if ((feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN) == 0)
 225                 return MICRON_ON_DIE_UNSUPPORTED;
 226
 227         ret = micron_nand_on_die_ecc_setup(chip, false);
 228         if (ret)
 229                 return MICRON_ON_DIE_UNSUPPORTED;
 230
 231         chip->onfi_get_features(nand_to_mtd(chip), chip,
 232                                 ONFI_FEATURE_ON_DIE_ECC, feature);
 233         if (feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN)
 234                 return MICRON_ON_DIE_MANDATORY;
 235
 236         /*
 237          * Some Micron NANDs have an on-die ECC of 4/512, some other
 238          * 8/512. We only support the former.
 239          */
 240         if (chip->onfi_params.ecc_bits != 4)
 241                 return MICRON_ON_DIE_UNSUPPORTED;
 242
 243         return MICRON_ON_DIE_SUPPORTED;
 244 }
 245
 246 static int micron_nand_init(struct nand_chip *chip)
 247 {
 248         struct mtd_info *mtd = nand_to_mtd(chip);
 249         int ondie;
 250         int ret;
 251
 252         ret = micron_nand_onfi_init(chip);
 253         if (ret)
 254                 return ret;
 255
 256         if (mtd->writesize == 2048)
 257                 chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
 258
 259         ondie = micron_supports_on_die_ecc(chip);
 260
 261         if (ondie == MICRON_ON_DIE_MANDATORY) {
 262                 pr_err("On-die ECC forcefully enabled, not supported\n");
 263                 return -EINVAL;
 264         }
 265
 266         if (chip->ecc.mode == NAND_ECC_ON_DIE) {
 267                 if (ondie == MICRON_ON_DIE_UNSUPPORTED) {
 268                         pr_err("On-die ECC selected but not supported\n");
 269                         return -EINVAL;
 270                 }
 271
 272                 chip->ecc.bytes = 8;
 273                 chip->ecc.size = 512;
 274                 chip->ecc.strength = 4;
 275                 chip->ecc.algo = NAND_ECC_BCH;
 276                 chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
 277                 chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
 278                 chip->ecc.read_page_raw = nand_read_page_raw;
 279                 chip->ecc.write_page_raw = nand_write_page_raw;
 280
 281                 mtd_set_ooblayout(mtd, &micron_nand_on_die_ooblayout_ops);
 282         }
 283
 284         return 0;
 285 }
 286
 287 const struct nand_manufacturer_ops micron_nand_manuf_ops = {
 288         .init = micron_nand_init,
 289 };