1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Bad Block Table support for the OneNAND driver 4 * 5 * Copyright(c) 2005 Samsung Electronics 6 * Kyungmin Park <kyungmin.park@samsung.com> 7 * 8 * Derived from nand_bbt.c 9 * 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 buffer 21 * @param buf the buffer to search 22 * @param len the length of buffer to search 23 * @param paglen the pagelength 24 * @param td search pattern descriptor 25 * 26 * Check for a pattern at the given place. Used to search bad block 27 * tables and good / bad block identifiers. Same as check_pattern, but 28 * no optional empty check and the pattern is expected to start 29 * at offset 0. 30 * 31 */ 32 static 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 device 47 * @param mtd MTD device structure 48 * @param buf temporary buffer 49 * @param bd descriptor for the good/bad block search pattern 50 * @param chip create the table for a specific chip, -1 read all chips. 51 * Applies only if NAND_BBT_PERCHIP option is set 52 * 53 * Create a bad block table by scanning the device 54 * for the given good/bad block identify pattern 55 */ 56 static 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, ooblen; 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 = ooblen = 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 painful 78 */ 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 } else 116 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 table 125 * @param mtd MTD device structure 126 * @param bd descriptor for the good/bad block search pattern 127 * 128 * The function creates a memory based bbt by scanning the device 129 * for manufacturer / software marked good / bad blocks 130 */ 131 static 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 bad 140 * @param mtd MTD device structure 141 * @param offs offset in the device 142 * @param allowbbt allow access to bad block table region 143 */ 144 static 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 * @param mtd MTD device structure 170 * @param bd descriptor for the good/bad block search pattern 171 * 172 * The function checks, if a bad block table(s) is/are already 173 * available. If not it scans the device for manufacturer 174 * marked good / bad blocks and writes the bad block table(s) to 175 * the selected place. 176 * 177 * The bad block table memory is allocated here. It is freed 178 * by the onenand_release function. 179 * 180 */ 181 static 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 used 211 * while scanning a device for factory marked good / bad blocks. 212 */ 213 static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 214 215 static 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 device 224 * @param mtd MTD device structure 225 * 226 * This function selects the default bad block table 227 * support for the device and calls the onenand_scan_bbt function 228 */ 229 int 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