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1// SPDX-License-Identifier: GPL-2.02/*3 * Bad Block Table support for the OneNAND driver4 *5 * Copyright(c) 2005 Samsung Electronics6 * Kyungmin Park <kyungmin.park@samsung.com>7 *8 * Derived from nand_bbt.c9 *10 * TODO:11 * Split BBT core and chip specific BBT.12 */13 14#include <linux/slab.h>15#include <linux/mtd/mtd.h>16#include <linux/mtd/onenand.h>17#include <linux/export.h>18 19/**20 * check_short_pattern - [GENERIC] check if a pattern is in the buffer21 * @buf: the buffer to search22 * @len: the length of buffer to search23 * @paglen: the pagelength24 * @td: search pattern descriptor25 *26 * Check for a pattern at the given place. Used to search bad block27 * tables and good / bad block identifiers. Same as check_pattern, but28 * no optional empty check and the pattern is expected to start29 * at offset 0.30 *31 */32static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)33{34 int i;35 uint8_t *p = buf;36 37 /* Compare the pattern */38 for (i = 0; i < td->len; i++) {39 if (p[i] != td->pattern[i])40 return -1;41 }42 return 0;43}44 45/**46 * create_bbt - [GENERIC] Create a bad block table by scanning the device47 * @mtd: MTD device structure48 * @buf: temporary buffer49 * @bd: descriptor for the good/bad block search pattern50 * @chip: create the table for a specific chip, -1 read all chips.51 * Applies only if NAND_BBT_PERCHIP option is set52 *53 * Create a bad block table by scanning the device54 * for the given good/bad block identify pattern55 */56static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)57{58 struct onenand_chip *this = mtd->priv;59 struct bbm_info *bbm = this->bbm;60 int i, j, numblocks, len, scanlen;61 int startblock;62 loff_t from;63 size_t readlen;64 struct mtd_oob_ops ops = { };65 int rgn;66 67 printk(KERN_INFO "Scanning device for bad blocks\n");68 69 len = 2;70 71 /* We need only read few bytes from the OOB area */72 scanlen = 0;73 readlen = bd->len;74 75 /* chip == -1 case only */76 /* Note that numblocks is 2 * (real numblocks) here;77 * see i += 2 below as it makses shifting and masking less painful78 */79 numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);80 startblock = 0;81 from = 0;82 83 ops.mode = MTD_OPS_PLACE_OOB;84 ops.ooblen = readlen;85 ops.oobbuf = buf;86 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;87 88 for (i = startblock; i < numblocks; ) {89 int ret;90 91 for (j = 0; j < len; j++) {92 /* No need to read pages fully,93 * just read required OOB bytes */94 ret = onenand_bbt_read_oob(mtd,95 from + j * this->writesize + bd->offs, &ops);96 97 /* If it is a initial bad block, just ignore it */98 if (ret == ONENAND_BBT_READ_FATAL_ERROR)99 return -EIO;100 101 if (ret || check_short_pattern(&buf[j * scanlen],102 scanlen, this->writesize, bd)) {103 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);104 printk(KERN_INFO "OneNAND eraseblock %d is an "105 "initial bad block\n", i >> 1);106 mtd->ecc_stats.badblocks++;107 break;108 }109 }110 i += 2;111 112 if (FLEXONENAND(this)) {113 rgn = flexonenand_region(mtd, from);114 from += mtd->eraseregions[rgn].erasesize;115 } else116 from += (1 << bbm->bbt_erase_shift);117 }118 119 return 0;120}121 122 123/**124 * onenand_memory_bbt - [GENERIC] create a memory based bad block table125 * @mtd: MTD device structure126 * @bd: descriptor for the good/bad block search pattern127 *128 * The function creates a memory based bbt by scanning the device129 * for manufacturer / software marked good / bad blocks130 */131static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)132{133 struct onenand_chip *this = mtd->priv;134 135 return create_bbt(mtd, this->page_buf, bd, -1);136}137 138/**139 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad140 * @mtd: MTD device structure141 * @offs: offset in the device142 * @allowbbt: allow access to bad block table region143 */144static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)145{146 struct onenand_chip *this = mtd->priv;147 struct bbm_info *bbm = this->bbm;148 int block;149 uint8_t res;150 151 /* Get block number * 2 */152 block = (int) (onenand_block(this, offs) << 1);153 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;154 155 pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",156 (unsigned int) offs, block >> 1, res);157 158 switch ((int) res) {159 case 0x00: return 0;160 case 0x01: return 1;161 case 0x02: return allowbbt ? 0 : 1;162 }163 164 return 1;165}166 167/**168 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)169 * @mtd: MTD device structure170 * @bd: descriptor for the good/bad block search pattern171 *172 * The function checks, if a bad block table(s) is/are already173 * available. If not it scans the device for manufacturer174 * marked good / bad blocks and writes the bad block table(s) to175 * the selected place.176 *177 * The bad block table memory is allocated here. It is freed178 * by the onenand_release function.179 *180 */181static int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)182{183 struct onenand_chip *this = mtd->priv;184 struct bbm_info *bbm = this->bbm;185 int len, ret = 0;186 187 len = this->chipsize >> (this->erase_shift + 2);188 /* Allocate memory (2bit per block) and clear the memory bad block table */189 bbm->bbt = kzalloc(len, GFP_KERNEL);190 if (!bbm->bbt)191 return -ENOMEM;192 193 /* Set erase shift */194 bbm->bbt_erase_shift = this->erase_shift;195 196 if (!bbm->isbad_bbt)197 bbm->isbad_bbt = onenand_isbad_bbt;198 199 /* Scan the device to build a memory based bad block table */200 if ((ret = onenand_memory_bbt(mtd, bd))) {201 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");202 kfree(bbm->bbt);203 bbm->bbt = NULL;204 }205 206 return ret;207}208 209/*210 * Define some generic bad / good block scan pattern which are used211 * while scanning a device for factory marked good / bad blocks.212 */213static uint8_t scan_ff_pattern[] = { 0xff, 0xff };214 215static struct nand_bbt_descr largepage_memorybased = {216 .options = 0,217 .offs = 0,218 .len = 2,219 .pattern = scan_ff_pattern,220};221 222/**223 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device224 * @mtd: MTD device structure225 *226 * This function selects the default bad block table227 * support for the device and calls the onenand_scan_bbt function228 */229int onenand_default_bbt(struct mtd_info *mtd)230{231 struct onenand_chip *this = mtd->priv;232 struct bbm_info *bbm;233 234 this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);235 if (!this->bbm)236 return -ENOMEM;237 238 bbm = this->bbm;239 240 /* 1KB page has same configuration as 2KB page */241 if (!bbm->badblock_pattern)242 bbm->badblock_pattern = &largepage_memorybased;243 244 return onenand_scan_bbt(mtd, bbm->badblock_pattern);245}246