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 19 #ifdef CONFIG_CMD_ONENAND 20 21 #include <linux/mtd/compat.h> 22 #include <linux/mtd/mtd.h> 23 #include <linux/mtd/onenand.h> 24 #include <malloc.h> 25 26 #include <asm/errno.h> 27 28 /** 29 * check_short_pattern - [GENERIC] check if a pattern is in the buffer 30 * @param buf the buffer to search 31 * @param len the length of buffer to search 32 * @param paglen the pagelength 33 * @param td search pattern descriptor 34 * 35 * Check for a pattern at the given place. Used to search bad block 36 * tables and good / bad block identifiers. Same as check_pattern, but 37 * no optional empty check and the pattern is expected to start 38 * at offset 0. 39 */ 40 static int check_short_pattern(uint8_t * buf, int len, int paglen, 41 struct nand_bbt_descr *td) 42 { 43 int i; 44 uint8_t *p = buf; 45 46 /* Compare the pattern */ 47 for (i = 0; i < td->len; i++) { 48 if (p[i] != td->pattern[i]) 49 return -1; 50 } 51 return 0; 52 } 53 54 /** 55 * create_bbt - [GENERIC] Create a bad block table by scanning the device 56 * @param mtd MTD device structure 57 * @param buf temporary buffer 58 * @param bd descriptor for the good/bad block search pattern 59 * @param chip create the table for a specific chip, -1 read all chips. 60 * Applies only if NAND_BBT_PERCHIP option is set 61 * 62 * Create a bad block table by scanning the device 63 * for the given good/bad block identify pattern 64 */ 65 static int create_bbt(struct mtd_info *mtd, uint8_t * buf, 66 struct nand_bbt_descr *bd, int chip) 67 { 68 struct onenand_chip *this = mtd->priv; 69 struct bbm_info *bbm = this->bbm; 70 int i, j, numblocks, len, scanlen; 71 int startblock; 72 loff_t from; 73 size_t readlen, ooblen; 74 75 printk(KERN_INFO "Scanning device for bad blocks\n"); 76 77 len = 1; 78 79 /* We need only read few bytes from the OOB area */ 80 scanlen = ooblen = 0; 81 readlen = bd->len; 82 83 /* chip == -1 case only */ 84 /* Note that numblocks is 2 * (real numblocks) here; 85 * see i += 2 below as it makses shifting and masking less painful 86 */ 87 numblocks = mtd->size >> (bbm->bbt_erase_shift - 1); 88 startblock = 0; 89 from = 0; 90 91 for (i = startblock; i < numblocks;) { 92 int ret; 93 94 for (j = 0; j < len; j++) { 95 size_t retlen; 96 97 /* No need to read pages fully, 98 * just read required OOB bytes */ 99 ret = onenand_read_oob(mtd, 100 from + j * mtd->oobblock + 101 bd->offs, readlen, &retlen, 102 &buf[0]); 103 104 if (ret && ret != -EAGAIN) { 105 printk("ret = %d\n", ret); 106 return ret; 107 } 108 109 if (check_short_pattern 110 (&buf[j * scanlen], scanlen, mtd->oobblock, 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 from += (1 << bbm->bbt_erase_shift); 120 } 121 122 return 0; 123 } 124 125 /** 126 * onenand_memory_bbt - [GENERIC] create a memory based bad block table 127 * @param mtd MTD device structure 128 * @param bd descriptor for the good/bad block search pattern 129 * 130 * The function creates a memory based bbt by scanning the device 131 * for manufacturer / software marked good / bad blocks 132 */ 133 static inline int onenand_memory_bbt(struct mtd_info *mtd, 134 struct nand_bbt_descr *bd) 135 { 136 unsigned char data_buf[MAX_ONENAND_PAGESIZE]; 137 138 bd->options &= ~NAND_BBT_SCANEMPTY; 139 return create_bbt(mtd, data_buf, bd, -1); 140 } 141 142 /** 143 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad 144 * @param mtd MTD device structure 145 * @param offs offset in the device 146 * @param allowbbt allow access to bad block table region 147 */ 148 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) 149 { 150 struct onenand_chip *this = mtd->priv; 151 struct bbm_info *bbm = this->bbm; 152 int block; 153 uint8_t res; 154 155 /* Get block number * 2 */ 156 block = (int)(offs >> (bbm->bbt_erase_shift - 1)); 157 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; 158 159 MTDDEBUG (MTD_DEBUG_LEVEL2, 160 "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n", 161 (unsigned int)offs, block >> 1, res); 162 163 switch ((int)res) { 164 case 0x00: 165 return 0; 166 case 0x01: 167 return 1; 168 case 0x02: 169 return allowbbt ? 0 : 1; 170 } 171 172 return 1; 173 } 174 175 /** 176 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) 177 * @param mtd MTD device structure 178 * @param bd descriptor for the good/bad block search pattern 179 * 180 * The function checks, if a bad block table(s) is/are already 181 * available. If not it scans the device for manufacturer 182 * marked good / bad blocks and writes the bad block table(s) to 183 * the selected place. 184 * 185 * The bad block table memory is allocated here. It must be freed 186 * by calling the onenand_free_bbt function. 187 * 188 */ 189 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) 190 { 191 struct onenand_chip *this = mtd->priv; 192 struct bbm_info *bbm = this->bbm; 193 int len, ret = 0; 194 195 len = mtd->size >> (this->erase_shift + 2); 196 /* Allocate memory (2bit per block) */ 197 bbm->bbt = malloc(len); 198 if (!bbm->bbt) { 199 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n"); 200 return -ENOMEM; 201 } 202 /* Clear the memory bad block table */ 203 memset(bbm->bbt, 0x00, len); 204 205 /* Set the bad block position */ 206 bbm->badblockpos = ONENAND_BADBLOCK_POS; 207 208 /* Set erase shift */ 209 bbm->bbt_erase_shift = this->erase_shift; 210 211 if (!bbm->isbad_bbt) 212 bbm->isbad_bbt = onenand_isbad_bbt; 213 214 /* Scan the device to build a memory based bad block table */ 215 if ((ret = onenand_memory_bbt(mtd, bd))) { 216 printk(KERN_ERR 217 "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); 218 free(bbm->bbt); 219 bbm->bbt = NULL; 220 } 221 222 return ret; 223 } 224 225 /* 226 * Define some generic bad / good block scan pattern which are used 227 * while scanning a device for factory marked good / bad blocks. 228 */ 229 static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 230 231 static struct nand_bbt_descr largepage_memorybased = { 232 .options = 0, 233 .offs = 0, 234 .len = 2, 235 .pattern = scan_ff_pattern, 236 }; 237 238 /** 239 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device 240 * @param mtd MTD device structure 241 * 242 * This function selects the default bad block table 243 * support for the device and calls the onenand_scan_bbt function 244 */ 245 int onenand_default_bbt(struct mtd_info *mtd) 246 { 247 struct onenand_chip *this = mtd->priv; 248 struct bbm_info *bbm; 249 250 this->bbm = malloc(sizeof(struct bbm_info)); 251 if (!this->bbm) 252 return -ENOMEM; 253 254 bbm = this->bbm; 255 256 memset(bbm, 0, sizeof(struct bbm_info)); 257 258 /* 1KB page has same configuration as 2KB page */ 259 if (!bbm->badblock_pattern) 260 bbm->badblock_pattern = &largepage_memorybased; 261 262 return onenand_scan_bbt(mtd, bbm->badblock_pattern); 263 } 264 265 #endif /* CFG_CMD_ONENAND */ 266