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_ADDR_READ_RETRY, p->get_feature_list);
  70         }
  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 nand_set_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 112 }
 113
 114 static int
 115 micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 116                                  uint8_t *buf, int oob_required,
 117                                  int page)
 118 {
 119         u8 status;
 120         int ret, max_bitflips = 0;
 121
 122         ret = micron_nand_on_die_ecc_setup(chip, true);
 123         if (ret)
 124                 return ret;
 125
 126         ret = nand_read_page_op(chip, page, 0, NULL, 0);
 127         if (ret)
 128                 goto out;
 129
 130         ret = nand_status_op(chip, &status);
 131         if (ret)
 132                 goto out;
 133
 134         ret = nand_exit_status_op(chip);
 135         if (ret)
 136                 goto out;
 137
 138         if (status & NAND_STATUS_FAIL)
 139                 mtd->ecc_stats.failed++;
 140
 141         /*
 142          * The internal ECC doesn't tell us the number of bitflips
 143          * that have been corrected, but tells us if it recommends to
 144          * rewrite the block. If it's the case, then we pretend we had
 145          * a number of bitflips equal to the ECC strength, which will
 146          * hint the NAND core to rewrite the block.
 147          */
 148         else if (status & NAND_STATUS_WRITE_RECOMMENDED)
 149                 max_bitflips = chip->ecc.strength;
 150
 151         ret = nand_read_data_op(chip, buf, mtd->writesize, false);
 152         if (!ret && oob_required)
 153                 ret = nand_read_data_op(chip, chip->oob_poi, mtd->oobsize,
 154                                         false);
 155
 156 out:
 157         micron_nand_on_die_ecc_setup(chip, false);
 158
 159         return ret ? ret : max_bitflips;
 160 }
 161
 162 static int
 163 micron_nand_write_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip,
 164                                   const uint8_t *buf, int oob_required,
 165                                   int page)
 166 {
 167         int ret;
 168
 169         ret = micron_nand_on_die_ecc_setup(chip, true);
 170         if (ret)
 171                 return ret;
 172
 173         ret = nand_write_page_raw(mtd, chip, buf, oob_required, page);
 174         micron_nand_on_die_ecc_setup(chip, false);
 175
 176         return ret;
 177 }
 178
 179 enum {
 180         /* The NAND flash doesn't support on-die ECC */
 181         MICRON_ON_DIE_UNSUPPORTED,
 182
 183         /*
 184          * The NAND flash supports on-die ECC and it can be
 185          * enabled/disabled by a set features command.
 186          */
 187         MICRON_ON_DIE_SUPPORTED,
 188
 189         /*
 190          * The NAND flash supports on-die ECC, and it cannot be
 191          * disabled.
 192          */
 193         MICRON_ON_DIE_MANDATORY,
 194 };
 195
 196 /*
 197  * Try to detect if the NAND support on-die ECC. To do this, we enable
 198  * the feature, and read back if it has been enabled as expected. We
 199  * also check if it can be disabled, because some Micron NANDs do not
 200  * allow disabling the on-die ECC and we don't support such NANDs for
 201  * now.
 202  *
 203  * This function also has the side effect of disabling on-die ECC if
 204  * it had been left enabled by the firmware/bootloader.
 205  */
 206 static int micron_supports_on_die_ecc(struct nand_chip *chip)
 207 {
 208         u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
 209         int ret;
 210
 211         if (!chip->parameters.onfi.version)
 212                 return MICRON_ON_DIE_UNSUPPORTED;
 213
 214         if (chip->bits_per_cell != 1)
 215                 return MICRON_ON_DIE_UNSUPPORTED;
 216
 217         ret = micron_nand_on_die_ecc_setup(chip, true);
 218         if (ret)
 219                 return MICRON_ON_DIE_UNSUPPORTED;
 220
 221         ret = nand_get_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 222         if (ret < 0)
 223                 return ret;
 224
 225         if ((feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN) == 0)
 226                 return MICRON_ON_DIE_UNSUPPORTED;
 227
 228         ret = micron_nand_on_die_ecc_setup(chip, false);
 229         if (ret)
 230                 return MICRON_ON_DIE_UNSUPPORTED;
 231
 232         ret = nand_get_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
 233         if (ret < 0)
 234                 return ret;
 235
 236         if (feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN)
 237                 return MICRON_ON_DIE_MANDATORY;
 238
 239         /*
 240          * Some Micron NANDs have an on-die ECC of 4/512, some other
 241          * 8/512. We only support the former.
 242          */
 243         if (chip->ecc_strength_ds != 4)
 244                 return MICRON_ON_DIE_UNSUPPORTED;
 245
 246         return MICRON_ON_DIE_SUPPORTED;
 247 }
 248
 249 static int micron_nand_init(struct nand_chip *chip)
 250 {
 251         struct mtd_info *mtd = nand_to_mtd(chip);
 252         int ondie;
 253         int ret;
 254
 255         ret = micron_nand_onfi_init(chip);
 256         if (ret)
 257                 return ret;
 258
 259         if (mtd->writesize == 2048)
 260                 chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
 261
 262         ondie = micron_supports_on_die_ecc(chip);
 263
 264         if (ondie == MICRON_ON_DIE_MANDATORY) {
 265                 pr_err("On-die ECC forcefully enabled, not supported\n");
 266                 return -EINVAL;
 267         }
 268
 269         if (chip->ecc.mode == NAND_ECC_ON_DIE) {
 270                 if (ondie == MICRON_ON_DIE_UNSUPPORTED) {
 271                         pr_err("On-die ECC selected but not supported\n");
 272                         return -EINVAL;
 273                 }
 274
 275                 chip->ecc.bytes = 8;
 276                 chip->ecc.size = 512;
 277                 chip->ecc.strength = 4;
 278                 chip->ecc.algo = NAND_ECC_BCH;
 279                 chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
 280                 chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
 281                 chip->ecc.read_page_raw = nand_read_page_raw;
 282                 chip->ecc.write_page_raw = nand_write_page_raw;
 283
 284                 mtd_set_ooblayout(mtd, &micron_nand_on_die_ooblayout_ops);
 285         }
 286
 287         return 0;
 288 }
 289
 290 const struct nand_manufacturer_ops micron_nand_manuf_ops = {
 291         .init = micron_nand_init,
 292 };