1 /* 2 * linux/drivers/mtd/onenand/onenand_bbt.c 3 * 4 * Bad Block Table support for the OneNAND driver 5 * 6 * Copyright(c) 2005-2007 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/mtd/compat.h> 19 #include <linux/mtd/mtd.h> 20 #include <linux/mtd/onenand.h> 21 #include <malloc.h> 22 23 #include <asm/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 73 printk(KERN_INFO "Scanning device for bad blocks\n"); 74 75 len = 1; 76 77 /* We need only read few bytes from the OOB area */ 78 scanlen = ooblen = 0; 79 readlen = bd->len; 80 81 /* chip == -1 case only */ 82 /* Note that numblocks is 2 * (real numblocks) here; 83 * see i += 2 below as it makses shifting and masking less painful 84 */ 85 numblocks = mtd->size >> (bbm->bbt_erase_shift - 1); 86 startblock = 0; 87 from = 0; 88 89 ops.mode = MTD_OOB_PLACE; 90 ops.ooblen = readlen; 91 ops.oobbuf = buf; 92 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0; 93 94 for (i = startblock; i < numblocks;) { 95 int ret; 96 97 for (j = 0; j < len; j++) { 98 /* No need to read pages fully, 99 * just read required OOB bytes */ 100 ret = onenand_bbt_read_oob(mtd, 101 from + j * mtd->writesize + 102 bd->offs, &ops); 103 104 /* If it is a initial bad block, just ignore it */ 105 if (ret == ONENAND_BBT_READ_FATAL_ERROR) 106 return -EIO; 107 108 if (ret || check_short_pattern 109 (&buf[j * scanlen], scanlen, mtd->writesize, bd)) { 110 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); 111 printk(KERN_WARNING 112 "Bad eraseblock %d at 0x%08x\n", i >> 1, 113 (unsigned int)from); 114 break; 115 } 116 } 117 i += 2; 118 from += (1 << bbm->bbt_erase_shift); 119 } 120 121 return 0; 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 */ 132 static inline int onenand_memory_bbt(struct mtd_info *mtd, 133 struct nand_bbt_descr *bd) 134 { 135 unsigned char data_buf[MAX_ONENAND_PAGESIZE]; 136 137 bd->options &= ~NAND_BBT_SCANEMPTY; 138 return create_bbt(mtd, data_buf, bd, -1); 139 } 140 141 /** 142 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad 143 * @param mtd MTD device structure 144 * @param offs offset in the device 145 * @param allowbbt allow access to bad block table region 146 */ 147 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) 148 { 149 struct onenand_chip *this = mtd->priv; 150 struct bbm_info *bbm = this->bbm; 151 int block; 152 uint8_t res; 153 154 /* Get block number * 2 */ 155 block = (int)(offs >> (bbm->bbt_erase_shift - 1)); 156 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; 157 158 MTDDEBUG (MTD_DEBUG_LEVEL2, 159 "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n", 160 (unsigned int)offs, block >> 1, res); 161 162 switch ((int)res) { 163 case 0x00: 164 return 0; 165 case 0x01: 166 return 1; 167 case 0x02: 168 return allowbbt ? 0 : 1; 169 } 170 171 return 1; 172 } 173 174 /** 175 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) 176 * @param mtd MTD device structure 177 * @param bd descriptor for the good/bad block search pattern 178 * 179 * The function checks, if a bad block table(s) is/are already 180 * available. If not it scans the device for manufacturer 181 * marked good / bad blocks and writes the bad block table(s) to 182 * the selected place. 183 * 184 * The bad block table memory is allocated here. It must be freed 185 * by calling the onenand_free_bbt function. 186 * 187 */ 188 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) 189 { 190 struct onenand_chip *this = mtd->priv; 191 struct bbm_info *bbm = this->bbm; 192 int len, ret = 0; 193 194 len = mtd->size >> (this->erase_shift + 2); 195 /* Allocate memory (2bit per block) */ 196 bbm->bbt = malloc(len); 197 if (!bbm->bbt) { 198 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n"); 199 return -ENOMEM; 200 } 201 /* Clear the memory bad block table */ 202 memset(bbm->bbt, 0x00, len); 203 204 /* Set the bad block position */ 205 bbm->badblockpos = ONENAND_BADBLOCK_POS; 206 207 /* Set erase shift */ 208 bbm->bbt_erase_shift = this->erase_shift; 209 210 if (!bbm->isbad_bbt) 211 bbm->isbad_bbt = onenand_isbad_bbt; 212 213 /* Scan the device to build a memory based bad block table */ 214 if ((ret = onenand_memory_bbt(mtd, bd))) { 215 printk(KERN_ERR 216 "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); 217 free(bbm->bbt); 218 bbm->bbt = NULL; 219 } 220 221 return ret; 222 } 223 224 /* 225 * Define some generic bad / good block scan pattern which are used 226 * while scanning a device for factory marked good / bad blocks. 227 */ 228 static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 229 230 static struct nand_bbt_descr largepage_memorybased = { 231 .options = 0, 232 .offs = 0, 233 .len = 2, 234 .pattern = scan_ff_pattern, 235 }; 236 237 /** 238 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device 239 * @param mtd MTD device structure 240 * 241 * This function selects the default bad block table 242 * support for the device and calls the onenand_scan_bbt function 243 */ 244 int onenand_default_bbt(struct mtd_info *mtd) 245 { 246 struct onenand_chip *this = mtd->priv; 247 struct bbm_info *bbm; 248 249 this->bbm = malloc(sizeof(struct bbm_info)); 250 if (!this->bbm) 251 return -ENOMEM; 252 253 bbm = this->bbm; 254 255 memset(bbm, 0, sizeof(struct bbm_info)); 256 257 /* 1KB page has same configuration as 2KB page */ 258 if (!bbm->badblock_pattern) 259 bbm->badblock_pattern = &largepage_memorybased; 260 261 return onenand_scan_bbt(mtd, bbm->badblock_pattern); 262 } 263