/* * linux/drivers/mtd/onenand/onenand_bbt.c * * Bad Block Table support for the OneNAND driver * * Copyright(c) 2005 Samsung Electronics * Kyungmin Park * * Derived from nand_bbt.c * * TODO: * Split BBT core and chip specific BBT. */ #include #include #include #include extern int onenand_do_read_oob(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf); /** * check_short_pattern - [GENERIC] check if a pattern is in the buffer * @param buf the buffer to search * @param len the length of buffer to search * @param paglen the pagelength * @param td search pattern descriptor * * Check for a pattern at the given place. Used to search bad block * tables and good / bad block identifiers. Same as check_pattern, but * no optional empty check and the pattern is expected to start * at offset 0. * */ static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td) { int i; uint8_t *p = buf; /* Compare the pattern */ for (i = 0; i < td->len; i++) { if (p[i] != td->pattern[i]) return -1; } return 0; } /** * create_bbt - [GENERIC] Create a bad block table by scanning the device * @param mtd MTD device structure * @param buf temporary buffer * @param bd descriptor for the good/bad block search pattern * @param chip create the table for a specific chip, -1 read all chips. * Applies only if NAND_BBT_PERCHIP option is set * * Create a bad block table by scanning the device * for the given good/bad block identify pattern */ static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip) { struct onenand_chip *this = mtd->priv; struct bbm_info *bbm = this->bbm; int i, j, numblocks, len, scanlen; int startblock; loff_t from; size_t readlen, ooblen; printk(KERN_INFO "Scanning device for bad blocks\n"); len = 1; /* We need only read few bytes from the OOB area */ scanlen = ooblen = 0; readlen = bd->len; /* chip == -1 case only */ /* Note that numblocks is 2 * (real numblocks) here; * see i += 2 below as it makses shifting and masking less painful */ numblocks = mtd->size >> (bbm->bbt_erase_shift - 1); startblock = 0; from = 0; for (i = startblock; i < numblocks; ) { int ret; for (j = 0; j < len; j++) { size_t retlen; /* No need to read pages fully, * just read required OOB bytes */ ret = onenand_do_read_oob(mtd, from + j * mtd->writesize + bd->offs, readlen, &retlen, &buf[0]); if (ret) return ret; if (check_short_pattern(&buf[j * scanlen], scanlen, mtd->writesize, bd)) { bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n", i >> 1, (unsigned int) from); break; } } i += 2; from += (1 << bbm->bbt_erase_shift); } return 0; } /** * onenand_memory_bbt - [GENERIC] create a memory based bad block table * @param mtd MTD device structure * @param bd descriptor for the good/bad block search pattern * * The function creates a memory based bbt by scanning the device * for manufacturer / software marked good / bad blocks */ static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd) { struct onenand_chip *this = mtd->priv; bd->options &= ~NAND_BBT_SCANEMPTY; return create_bbt(mtd, this->page_buf, bd, -1); } /** * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad * @param mtd MTD device structure * @param offs offset in the device * @param allowbbt allow access to bad block table region */ static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt) { struct onenand_chip *this = mtd->priv; struct bbm_info *bbm = this->bbm; int block; uint8_t res; /* Get block number * 2 */ block = (int) (offs >> (bbm->bbt_erase_shift - 1)); res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03; DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n", (unsigned int) offs, block >> 1, res); switch ((int) res) { case 0x00: return 0; case 0x01: return 1; case 0x02: return allowbbt ? 0 : 1; } return 1; } /** * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) * @param mtd MTD device structure * @param bd descriptor for the good/bad block search pattern * * The function checks, if a bad block table(s) is/are already * available. If not it scans the device for manufacturer * marked good / bad blocks and writes the bad block table(s) to * the selected place. * * The bad block table memory is allocated here. It must be freed * by calling the onenand_free_bbt function. * */ int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd) { struct onenand_chip *this = mtd->priv; struct bbm_info *bbm = this->bbm; int len, ret = 0; len = mtd->size >> (this->erase_shift + 2); /* Allocate memory (2bit per block) and clear the memory bad block table */ bbm->bbt = kzalloc(len, GFP_KERNEL); if (!bbm->bbt) { printk(KERN_ERR "onenand_scan_bbt: Out of memory\n"); return -ENOMEM; } /* Set the bad block position */ bbm->badblockpos = ONENAND_BADBLOCK_POS; /* Set erase shift */ bbm->bbt_erase_shift = this->erase_shift; if (!bbm->isbad_bbt) bbm->isbad_bbt = onenand_isbad_bbt; /* Scan the device to build a memory based bad block table */ if ((ret = onenand_memory_bbt(mtd, bd))) { printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n"); kfree(bbm->bbt); bbm->bbt = NULL; } return ret; } /* * Define some generic bad / good block scan pattern which are used * while scanning a device for factory marked good / bad blocks. */ static uint8_t scan_ff_pattern[] = { 0xff, 0xff }; static struct nand_bbt_descr largepage_memorybased = { .options = 0, .offs = 0, .len = 2, .pattern = scan_ff_pattern, }; /** * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device * @param mtd MTD device structure * * This function selects the default bad block table * support for the device and calls the onenand_scan_bbt function */ int onenand_default_bbt(struct mtd_info *mtd) { struct onenand_chip *this = mtd->priv; struct bbm_info *bbm; this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL); if (!this->bbm) return -ENOMEM; bbm = this->bbm; /* 1KB page has same configuration as 2KB page */ if (!bbm->badblock_pattern) bbm->badblock_pattern = &largepage_memorybased; return onenand_scan_bbt(mtd, bbm->badblock_pattern); } EXPORT_SYMBOL(onenand_scan_bbt); EXPORT_SYMBOL(onenand_default_bbt);