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/mtd/compatmac.h> 19 20extern int onenand_bbt_read_oob(struct mtd_info *mtd, loff_t from, 21 struct mtd_oob_ops *ops); 22 23/** 24 * check_short_pattern - [GENERIC] check if a pattern is in the buffer 25 * @param buf the buffer to search 26 * @param len the length of buffer to search 27 * @param paglen the pagelength 28 * @param td search pattern descriptor 29 * 30 * Check for a pattern at the given place. Used to search bad block 31 * tables and good / bad block identifiers. Same as check_pattern, but 32 * no optional empty check and the pattern is expected to start 33 * at offset 0. 34 * 35 */ 36static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td) 37{ 38 int i; 39 uint8_t *p = buf; 40 41 /* Compare the pattern */ 42 for (i = 0; i < td->len; i++) { 43 if (p[i] != td->pattern[i]) 44 return -1; 45 } 46 return 0; 47} 48 49/** 50 * create_bbt - [GENERIC] Create a bad block table by scanning the device 51 * @param mtd MTD device structure 52 * @param buf temporary buffer 53 * @param bd descriptor for the good/bad block search pattern 54 * @param chip create the table for a specific chip, -1 read all chips. 55 * Applies only if NAND_BBT_PERCHIP option is set 56 * 57 * Create a bad block table by scanning the device 58 * for the given good/bad block identify pattern 59 */ 60static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip) 61{ 62 struct onenand_chip *this = mtd->priv; 63 struct bbm_info *bbm = this->bbm; 64 int i, j, numblocks, len, scanlen; 65 int startblock; 66 loff_t from; 67 size_t readlen, ooblen; 68 struct mtd_oob_ops ops; 69 70 printk(KERN_INFO "Scanning device for bad blocks\n"); 71 72 len = 2; 73 74 /* We need only read few bytes from the OOB area */ 75 scanlen = ooblen = 0; 76 readlen = bd->len; 77 78 /* chip == -1 case only */ 79 /* Note that numblocks is 2 * (real numblocks) here; 80 * see i += 2 below as it makses shifting and masking less painful 81 */ 82 numblocks = mtd->size >> (bbm->bbt_erase_shift - 1); 83 startblock = 0; 84 from = 0; 85 86 ops.mode = MTD_OOB_PLACE; 87 ops.ooblen = readlen; 88 ops.oobbuf = buf; 89 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0; 90 91 for (i = startblock; i < numblocks; ) { 92 int ret; 93 94 for (j = 0; j < len; j++) { 95 /* No need to read pages fully, 96 * just read required OOB bytes */ 97 ret = onenand_bbt_read_oob(mtd, from + j * mtd->writesize + bd->offs, &ops); 98 99 /* If it is a initial bad block, just ignore it */ 100 if (ret == ONENAND_BBT_READ_FATAL_ERROR) 101 return -EIO; 102 103 if (ret || check_short_pattern(&buf[j * scanlen], scanlen, mtd->writesize, bd)) { 104 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); 105 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n", 106 i >> 1, (unsigned int) from); 107 mtd->ecc_stats.badblocks++; 108 break; 109 } 110 } 111 i += 2; 112 from += (1 << bbm->bbt_erase_shift); 113 } 114 115 return 0; 116} 117 118 119/** 120 * onenand_memory_bbt - [GENERIC] create a memory based bad block table 121 * @param mtd MTD device structure 122 * @param bd descriptor for the good/bad block search pattern 123 * 124 * The function creates a memory based bbt by scanning the device 125 * for manufacturer / software marked good / bad blocks 126 */ 127static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd) 128{ 129 struct onenand_chip *this = mtd->priv; 130 131 bd->options &= ~NAND_BBT_SCANEMPTY; 132 return create_bbt(mtd, this->page_buf, bd, -1); 133} 134 135/** 136 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad 137 * @param mtd MTD device structure 138 * @param offs offset in the device 139 * @param allowbbt allow access to bad block table region 140 */ 141static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) 142{ 143 struct onenand_chip *this = mtd->priv; 144 struct bbm_info *bbm = this->bbm; 145 int block; 146 uint8_t res; 147 148 /* Get block number * 2 */ 149 block = (int) (offs >> (bbm->bbt_erase_shift - 1)); 150 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; 151 152 DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n", 153 (unsigned int) offs, block >> 1, res); 154 155 switch ((int) res) { 156 case 0x00: return 0; 157 case 0x01: return 1; 158 case 0x02: return allowbbt ? 0 : 1; 159 } 160 161 return 1; 162} 163 164/** 165 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) 166 * @param mtd MTD device structure 167 * @param bd descriptor for the good/bad block search pattern 168 * 169 * The function checks, if a bad block table(s) is/are already 170 * available. If not it scans the device for manufacturer 171 * marked good / bad blocks and writes the bad block table(s) to 172 * the selected place. 173 * 174 * The bad block table memory is allocated here. It is freed 175 * by the onenand_release function. 176 * 177 */ 178int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) 179{ 180 struct onenand_chip *this = mtd->priv; 181 struct bbm_info *bbm = this->bbm; 182 int len, ret = 0; 183 184 len = mtd->size >> (this->erase_shift + 2); 185 /* Allocate memory (2bit per block) and clear the memory bad block table */ 186 bbm->bbt = kzalloc(len, GFP_KERNEL); 187 if (!bbm->bbt) { 188 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n"); 189 return -ENOMEM; 190 } 191 192 /* Set the bad block position */ 193 bbm->badblockpos = ONENAND_BADBLOCK_POS; 194 195 /* Set erase shift */ 196 bbm->bbt_erase_shift = this->erase_shift; 197 198 if (!bbm->isbad_bbt) 199 bbm->isbad_bbt = onenand_isbad_bbt; 200 201 /* Scan the device to build a memory based bad block table */ 202 if ((ret = onenand_memory_bbt(mtd, bd))) { 203 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); 204 kfree(bbm->bbt); 205 bbm->bbt = NULL; 206 } 207 208 return ret; 209} 210 211/* 212 * Define some generic bad / good block scan pattern which are used 213 * while scanning a device for factory marked good / bad blocks. 214 */ 215static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 216 217static struct nand_bbt_descr largepage_memorybased = { 218 .options = 0, 219 .offs = 0, 220 .len = 2, 221 .pattern = scan_ff_pattern, 222}; 223 224/** 225 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device 226 * @param mtd MTD device structure 227 * 228 * This function selects the default bad block table 229 * support for the device and calls the onenand_scan_bbt function 230 */ 231int onenand_default_bbt(struct mtd_info *mtd) 232{ 233 struct onenand_chip *this = mtd->priv; 234 struct bbm_info *bbm; 235 236 this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL); 237 if (!this->bbm) 238 return -ENOMEM; 239 240 bbm = this->bbm; 241 242 /* 1KB page has same configuration as 2KB page */ 243 if (!bbm->badblock_pattern) 244 bbm->badblock_pattern = &largepage_memorybased; 245 246 return onenand_scan_bbt(mtd, bbm->badblock_pattern); 247} 248 249EXPORT_SYMBOL(onenand_scan_bbt); 250EXPORT_SYMBOL(onenand_default_bbt); 251