1/* 2 * linux/drivers/mtd/onenand/onenand_bbt.c 3 * 4 * Bad Block Table support for the OneNAND driver 5 * 6 * Copyright(c) 2005 Samsung Electronics 7 * Kyungmin Park <kyungmin.park@samsung.com> 8 * 9 * Derived from nand_bbt.c 10 * 11 * TODO: 12 * Split BBT core and chip specific BBT. 13 */ 14 15#include <linux/slab.h> 16#include <linux/mtd/mtd.h> 17#include <linux/mtd/onenand.h> 18#include <linux/export.h> 19 20/** 21 * check_short_pattern - [GENERIC] check if a pattern is in the buffer 22 * @param buf the buffer to search 23 * @param len the length of buffer to search 24 * @param paglen the pagelength 25 * @param td search pattern descriptor 26 * 27 * Check for a pattern at the given place. Used to search bad block 28 * tables and good / bad block identifiers. Same as check_pattern, but 29 * no optional empty check and the pattern is expected to start 30 * at offset 0. 31 * 32 */ 33static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td) 34{ 35 int i; 36 uint8_t *p = buf; 37 38 /* Compare the pattern */ 39 for (i = 0; i < td->len; i++) { 40 if (p[i] != td->pattern[i]) 41 return -1; 42 } 43 return 0; 44} 45 46/** 47 * create_bbt - [GENERIC] Create a bad block table by scanning the device 48 * @param mtd MTD device structure 49 * @param buf temporary buffer 50 * @param bd descriptor for the good/bad block search pattern 51 * @param chip create the table for a specific chip, -1 read all chips. 52 * Applies only if NAND_BBT_PERCHIP option is set 53 * 54 * Create a bad block table by scanning the device 55 * for the given good/bad block identify pattern 56 */ 57static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip) 58{ 59 struct onenand_chip *this = mtd->priv; 60 struct bbm_info *bbm = this->bbm; 61 int i, j, numblocks, len, scanlen; 62 int startblock; 63 loff_t from; 64 size_t readlen, ooblen; 65 struct mtd_oob_ops ops; 66 int rgn; 67 68 printk(KERN_INFO "Scanning device for bad blocks\n"); 69 70 len = 2; 71 72 /* We need only read few bytes from the OOB area */ 73 scanlen = ooblen = 0; 74 readlen = bd->len; 75 76 /* chip == -1 case only */ 77 /* Note that numblocks is 2 * (real numblocks) here; 78 * see i += 2 below as it makses shifting and masking less painful 79 */ 80 numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1); 81 startblock = 0; 82 from = 0; 83 84 ops.mode = MTD_OPS_PLACE_OOB; 85 ops.ooblen = readlen; 86 ops.oobbuf = buf; 87 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0; 88 89 for (i = startblock; i < numblocks; ) { 90 int ret; 91 92 for (j = 0; j < len; j++) { 93 /* No need to read pages fully, 94 * just read required OOB bytes */ 95 ret = onenand_bbt_read_oob(mtd, 96 from + j * this->writesize + bd->offs, &ops); 97 98 /* If it is a initial bad block, just ignore it */ 99 if (ret == ONENAND_BBT_READ_FATAL_ERROR) 100 return -EIO; 101 102 if (ret || check_short_pattern(&buf[j * scanlen], 103 scanlen, this->writesize, bd)) { 104 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); 105 printk(KERN_INFO "OneNAND eraseblock %d is an " 106 "initial bad block\n", i >> 1); 107 mtd->ecc_stats.badblocks++; 108 break; 109 } 110 } 111 i += 2; 112 113 if (FLEXONENAND(this)) { 114 rgn = flexonenand_region(mtd, from); 115 from += mtd->eraseregions[rgn].erasesize; 116 } else 117 from += (1 << bbm->bbt_erase_shift); 118 } 119 120 return 0; 121} 122 123 124/** 125 * onenand_memory_bbt - [GENERIC] create a memory based bad block table 126 * @param mtd MTD device structure 127 * @param bd descriptor for the good/bad block search pattern 128 * 129 * The function creates a memory based bbt by scanning the device 130 * for manufacturer / software marked good / bad blocks 131 */ 132static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd) 133{ 134 struct onenand_chip *this = mtd->priv; 135 136 bd->options &= ~NAND_BBT_SCANEMPTY; 137 return create_bbt(mtd, this->page_buf, bd, -1); 138} 139 140/** 141 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad 142 * @param mtd MTD device structure 143 * @param offs offset in the device 144 * @param allowbbt allow access to bad block table region 145 */ 146static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) 147{ 148 struct onenand_chip *this = mtd->priv; 149 struct bbm_info *bbm = this->bbm; 150 int block; 151 uint8_t res; 152 153 /* Get block number * 2 */ 154 block = (int) (onenand_block(this, offs) << 1); 155 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; 156 157 pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n", 158 (unsigned int) offs, block >> 1, res); 159 160 switch ((int) res) { 161 case 0x00: return 0; 162 case 0x01: return 1; 163 case 0x02: return allowbbt ? 0 : 1; 164 } 165 166 return 1; 167} 168 169/** 170 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) 171 * @param mtd MTD device structure 172 * @param bd descriptor for the good/bad block search pattern 173 * 174 * The function checks, if a bad block table(s) is/are already 175 * available. If not it scans the device for manufacturer 176 * marked good / bad blocks and writes the bad block table(s) to 177 * the selected place. 178 * 179 * The bad block table memory is allocated here. It is freed 180 * by the onenand_release function. 181 * 182 */ 183int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) 184{ 185 struct onenand_chip *this = mtd->priv; 186 struct bbm_info *bbm = this->bbm; 187 int len, ret = 0; 188 189 len = this->chipsize >> (this->erase_shift + 2); 190 /* Allocate memory (2bit per block) and clear the memory bad block table */ 191 bbm->bbt = kzalloc(len, GFP_KERNEL); 192 if (!bbm->bbt) 193 return -ENOMEM; 194 195 /* Set the bad block position */ 196 bbm->badblockpos = ONENAND_BADBLOCK_POS; 197 198 /* Set erase shift */ 199 bbm->bbt_erase_shift = this->erase_shift; 200 201 if (!bbm->isbad_bbt) 202 bbm->isbad_bbt = onenand_isbad_bbt; 203 204 /* Scan the device to build a memory based bad block table */ 205 if ((ret = onenand_memory_bbt(mtd, bd))) { 206 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); 207 kfree(bbm->bbt); 208 bbm->bbt = NULL; 209 } 210 211 return ret; 212} 213 214/* 215 * Define some generic bad / good block scan pattern which are used 216 * while scanning a device for factory marked good / bad blocks. 217 */ 218static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 219 220static struct nand_bbt_descr largepage_memorybased = { 221 .options = 0, 222 .offs = 0, 223 .len = 2, 224 .pattern = scan_ff_pattern, 225}; 226 227/** 228 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device 229 * @param mtd MTD device structure 230 * 231 * This function selects the default bad block table 232 * support for the device and calls the onenand_scan_bbt function 233 */ 234int onenand_default_bbt(struct mtd_info *mtd) 235{ 236 struct onenand_chip *this = mtd->priv; 237 struct bbm_info *bbm; 238 239 this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL); 240 if (!this->bbm) 241 return -ENOMEM; 242 243 bbm = this->bbm; 244 245 /* 1KB page has same configuration as 2KB page */ 246 if (!bbm->badblock_pattern) 247 bbm->badblock_pattern = &largepage_memorybased; 248 249 return onenand_scan_bbt(mtd, bbm->badblock_pattern); 250} 251 252EXPORT_SYMBOL(onenand_scan_bbt); 253EXPORT_SYMBOL(onenand_default_bbt); 254