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 72 printk(KERN_INFO "Scanning device for bad blocks\n"); 73 74 len = 1; 75 76 /* We need only read few bytes from the OOB area */ 77 scanlen = ooblen = 0; 78 readlen = bd->len; 79 80 /* chip == -1 case only */ 81 /* Note that numblocks is 2 * (real numblocks) here; 82 * see i += 2 below as it makses shifting and masking less painful 83 */ 84 numblocks = mtd->size >> (bbm->bbt_erase_shift - 1); 85 startblock = 0; 86 from = 0; 87 88 for (i = startblock; i < numblocks;) { 89 int ret; 90 91 for (j = 0; j < len; j++) { 92 size_t retlen; 93 94 /* No need to read pages fully, 95 * just read required OOB bytes */ 96 ret = onenand_read_oob(mtd, 97 from + j * mtd->oobblock + 98 bd->offs, readlen, &retlen, 99 &buf[0]); 100 101 if (ret && ret != -EAGAIN) { 102 printk("ret = %d\n", ret); 103 return ret; 104 } 105 106 if (check_short_pattern 107 (&buf[j * scanlen], scanlen, mtd->oobblock, bd)) { 108 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); 109 printk(KERN_WARNING 110 "Bad eraseblock %d at 0x%08x\n", i >> 1, 111 (unsigned int)from); 112 break; 113 } 114 } 115 i += 2; 116 from += (1 << bbm->bbt_erase_shift); 117 } 118 119 return 0; 120 } 121 122 /** 123 * onenand_memory_bbt - [GENERIC] create a memory based bad block table 124 * @param mtd MTD device structure 125 * @param bd descriptor for the good/bad block search pattern 126 * 127 * The function creates a memory based bbt by scanning the device 128 * for manufacturer / software marked good / bad blocks 129 */ 130 static inline int onenand_memory_bbt(struct mtd_info *mtd, 131 struct nand_bbt_descr *bd) 132 { 133 unsigned char data_buf[MAX_ONENAND_PAGESIZE]; 134 135 bd->options &= ~NAND_BBT_SCANEMPTY; 136 return create_bbt(mtd, data_buf, bd, -1); 137 } 138 139 /** 140 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad 141 * @param mtd MTD device structure 142 * @param offs offset in the device 143 * @param allowbbt allow access to bad block table region 144 */ 145 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) 146 { 147 struct onenand_chip *this = mtd->priv; 148 struct bbm_info *bbm = this->bbm; 149 int block; 150 uint8_t res; 151 152 /* Get block number * 2 */ 153 block = (int)(offs >> (bbm->bbt_erase_shift - 1)); 154 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; 155 156 MTDDEBUG (MTD_DEBUG_LEVEL2, 157 "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: 162 return 0; 163 case 0x01: 164 return 1; 165 case 0x02: 166 return allowbbt ? 0 : 1; 167 } 168 169 return 1; 170 } 171 172 /** 173 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) 174 * @param mtd MTD device structure 175 * @param bd descriptor for the good/bad block search pattern 176 * 177 * The function checks, if a bad block table(s) is/are already 178 * available. If not it scans the device for manufacturer 179 * marked good / bad blocks and writes the bad block table(s) to 180 * the selected place. 181 * 182 * The bad block table memory is allocated here. It must be freed 183 * by calling the onenand_free_bbt function. 184 * 185 */ 186 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) 187 { 188 struct onenand_chip *this = mtd->priv; 189 struct bbm_info *bbm = this->bbm; 190 int len, ret = 0; 191 192 len = mtd->size >> (this->erase_shift + 2); 193 /* Allocate memory (2bit per block) */ 194 bbm->bbt = malloc(len); 195 if (!bbm->bbt) { 196 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n"); 197 return -ENOMEM; 198 } 199 /* Clear the memory bad block table */ 200 memset(bbm->bbt, 0x00, len); 201 202 /* Set the bad block position */ 203 bbm->badblockpos = ONENAND_BADBLOCK_POS; 204 205 /* Set erase shift */ 206 bbm->bbt_erase_shift = this->erase_shift; 207 208 if (!bbm->isbad_bbt) 209 bbm->isbad_bbt = onenand_isbad_bbt; 210 211 /* Scan the device to build a memory based bad block table */ 212 if ((ret = onenand_memory_bbt(mtd, bd))) { 213 printk(KERN_ERR 214 "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); 215 free(bbm->bbt); 216 bbm->bbt = NULL; 217 } 218 219 return ret; 220 } 221 222 /* 223 * Define some generic bad / good block scan pattern which are used 224 * while scanning a device for factory marked good / bad blocks. 225 */ 226 static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; 227 228 static struct nand_bbt_descr largepage_memorybased = { 229 .options = 0, 230 .offs = 0, 231 .len = 2, 232 .pattern = scan_ff_pattern, 233 }; 234 235 /** 236 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device 237 * @param mtd MTD device structure 238 * 239 * This function selects the default bad block table 240 * support for the device and calls the onenand_scan_bbt function 241 */ 242 int onenand_default_bbt(struct mtd_info *mtd) 243 { 244 struct onenand_chip *this = mtd->priv; 245 struct bbm_info *bbm; 246 247 this->bbm = malloc(sizeof(struct bbm_info)); 248 if (!this->bbm) 249 return -ENOMEM; 250 251 bbm = this->bbm; 252 253 memset(bbm, 0, sizeof(struct bbm_info)); 254 255 /* 1KB page has same configuration as 2KB page */ 256 if (!bbm->badblock_pattern) 257 bbm->badblock_pattern = &largepage_memorybased; 258 259 return onenand_scan_bbt(mtd, bbm->badblock_pattern); 260 } 261