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, µn_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 }; 295