1 /* 2 * linux/drivers/mtd/onenand/onenand_bbt.c 3 * 4 * Bad Block Table support for the OneNAND driver 5 * 6 * Copyright(c) 2005-2008 Samsung Electronics 7 * Kyungmin Park <kyungmin.park@samsung.com> 8 * 9 * TODO: 10 * Split BBT core and chip specific BBT. 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #include <common.h> 18 #include <linux/compat.h> 19 #include <linux/mtd/mtd.h> 20 #include <linux/mtd/onenand.h> 21 #include <malloc.h> 22 23 #include <linux/errno.h> 24 25 /** 26 * check_short_pattern - [GENERIC] check if a pattern is in the buffer 27 * @param buf the buffer to search 28 * @param len the length of buffer to search 29 * @param paglen the pagelength 30 * @param td search pattern descriptor 31 * 32 * Check for a pattern at the given place. Used to search bad block 33 * tables and good / bad block identifiers. Same as check_pattern, but 34 * no optional empty check and the pattern is expected to start 35 * at offset 0. 36 */ 37 static int check_short_pattern(uint8_t * buf, int len, int paglen, 38 struct nand_bbt_descr *td) 39 { 40 int i; 41 uint8_t *p = buf; 42 43 /* Compare the pattern */ 44 for (i = 0; i < td->len; i++) { 45 if (p[i] != td->pattern[i]) 46 return -1; 47 } 48 return 0; 49 } 50 51 /** 52 * create_bbt - [GENERIC] Create a bad block table by scanning the device 53 * @param mtd MTD device structure 54 * @param buf temporary buffer 55 * @param bd descriptor for the good/bad block search pattern 56 * @param chip create the table for a specific chip, -1 read all chips. 57 * Applies only if NAND_BBT_PERCHIP option is set 58 * 59 * Create a bad block table by scanning the device 60 * for the given good/bad block identify pattern 61 */ 62 static int create_bbt(struct mtd_info *mtd, uint8_t * buf, 63 struct nand_bbt_descr *bd, int chip) 64 { 65 struct onenand_chip *this = mtd->priv; 66 struct bbm_info *bbm = this->bbm; 67 int i, j, numblocks, len, scanlen; 68 int startblock; 69 loff_t from; 70 size_t readlen, ooblen; 71 struct mtd_oob_ops ops; 72 int rgn; 73 74 printk(KERN_INFO "Scanning device for bad blocks\n"); 75 76 len = 1; 77 78 /* We need only read few bytes from the OOB area */ 79 scanlen = ooblen = 0; 80 readlen = bd->len; 81 82 /* chip == -1 case only */ 83 /* Note that numblocks is 2 * (real numblocks) here; 84 * see i += 2 below as it makses shifting and masking less painful 85 */ 86 numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1); 87 startblock = 0; 88 from = 0; 89 90 ops.mode = MTD_OPS_PLACE_OOB; 91 ops.ooblen = readlen; 92 ops.oobbuf = buf; 93 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0; 94 95 for (i = startblock; i < numblocks;) { 96 int ret; 97 98 for (j = 0; j < len; j++) { 99 /* No need to read pages fully, 100 * just read required OOB bytes */ 101 ret = onenand_bbt_read_oob(mtd, 102 from + j * mtd->writesize + 103 bd->offs, &ops); 104 105 /* If it is a initial bad block, just ignore it */ 106 if (ret == ONENAND_BBT_READ_FATAL_ERROR) 107 return -EIO; 108 109 if (ret || check_short_pattern 110 (&buf[j * scanlen], scanlen, mtd->writesize, bd)) { 111 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); 112 printk(KERN_WARNING 113 "Bad eraseblock %d at 0x%08x\n", i >> 1, 114 (unsigned int)from); 115 break; 116 } 117 } 118 i += 2; 119 120 if (FLEXONENAND(this)) { 121 rgn = flexonenand_region(mtd, from); 122 from += mtd->eraseregions[rgn].erasesize; 123 } else 124 from += (1 << bbm->bbt_erase_shift); 125 } 126 127 return 0; 128 } 129 130 /** 131 * onenand_memory_bbt - [GENERIC] create a memory based bad block table 132 * @param mtd MTD device structure 133 * @param bd descriptor for the good/bad block search pattern 134 * 135 * The function creates a memory based bbt by scanning the device 136 * for manufacturer / software marked good / bad blocks 137 */ 138 static inline int onenand_memory_bbt(struct mtd_info *mtd, 139 struct nand_bbt_descr *bd) 140 { 141 unsigned char data_buf[MAX_ONENAND_PAGESIZE]; 142 143 return create_bbt(mtd, data_buf, bd, -1); 144 } 145 146 /** 147 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad 148 * @param mtd MTD device structure 149 * @param offs offset in the device 150 * @param allowbbt allow access to bad block table region 151 */ 152 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) 153 { 154 struct onenand_chip *this = mtd->priv; 155 struct bbm_info *bbm = this->bbm; 156 int block; 157 uint8_t res; 158 159 /* Get block number * 2 */ 160 block = (int) (onenand_block(this, offs) << 1); 161 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; 162 163 pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n", 164 (unsigned int)offs, block >> 1, res); 165 166 switch ((int)res) { 167 case 0x00: 168 return 0; 169 case 0x01: 170 return 1; 171 case 0x02: 172 return allowbbt ? 0 : 1; 173 } 174 175 return 1; 176 } 177 178 /** 179 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) 180 * @param mtd MTD device structure 181 * @param bd descriptor for the good/bad block search pattern 182 * 183 * The function checks, if a bad block table(s) is/are already 184 * available. If not it scans the device for manufacturer 185 * marked good / bad blocks and writes the bad block table(s) to 186 * the selected place. 187 * 188 * The bad block table memory is allocated here. It must be freed 189 * by calling the onenand_free_bbt function. 190 * 191 */ 192 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) 193 { 194 struct onenand_chip *this = mtd->priv; 195 struct bbm_info *bbm = this->bbm; 196 int len, ret = 0; 197 198 len = this->chipsize >> (this->erase_shift + 2); 199 /* Allocate memory (2bit per block) */ 200 bbm->bbt = malloc(len); 201 if (!bbm->bbt) 202 return -ENOMEM; 203 /* Clear the memory bad block table */ 204 memset(bbm->bbt, 0x00, len); 205 206 /* Set the bad block position */ 207 bbm->badblockpos = ONENAND_BADBLOCK_POS; 208 209 /* Set erase shift */ 210 bbm->bbt_erase_shift = this->erase_shift; 211 212 if (!bbm->isbad_bbt) 213 bbm->isbad_bbt = onenand_isbad_bbt; 214 215 /* Scan the device to build a memory based bad block table */ 216 if ((ret = onenand_memory_bbt(mtd, bd))) { 217 printk(KERN_ERR 218 "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); 219 free(bbm->bbt); 220 bbm->bbt = NULL; 221 } 222 223 return ret; 224 } 225 226 /* 227 * Define some generic bad / good block scan pattern which are used 228 * while scanning a device for factory marked good / bad blocks. 229 */ 230 static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 231 232 static struct nand_bbt_descr largepage_memorybased = { 233 .options = 0, 234 .offs = 0, 235 .len = 2, 236 .pattern = scan_ff_pattern, 237 }; 238 239 /** 240 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device 241 * @param mtd MTD device structure 242 * 243 * This function selects the default bad block table 244 * support for the device and calls the onenand_scan_bbt function 245 */ 246 int onenand_default_bbt(struct mtd_info *mtd) 247 { 248 struct onenand_chip *this = mtd->priv; 249 struct bbm_info *bbm; 250 251 this->bbm = malloc(sizeof(struct bbm_info)); 252 if (!this->bbm) 253 return -ENOMEM; 254 255 bbm = this->bbm; 256 257 memset(bbm, 0, sizeof(struct bbm_info)); 258 259 /* 1KB page has same configuration as 2KB page */ 260 if (!bbm->badblock_pattern) 261 bbm->badblock_pattern = &largepage_memorybased; 262 263 return onenand_scan_bbt(mtd, bbm->badblock_pattern); 264 } 265