246 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			246 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| // SPDX-License-Identifier: GPL-2.0
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| /*
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|  *  Bad Block Table support for the OneNAND driver
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|  *
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|  *  Copyright(c) 2005 Samsung Electronics
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|  *  Kyungmin Park <kyungmin.park@samsung.com>
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|  *
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|  *  Derived from nand_bbt.c
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|  *
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|  *  TODO:
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|  *    Split BBT core and chip specific BBT.
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|  */
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| 
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| #include <linux/slab.h>
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| #include <linux/mtd/mtd.h>
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| #include <linux/mtd/onenand.h>
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| #include <linux/export.h>
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| 
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| /**
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|  * check_short_pattern - [GENERIC] check if a pattern is in the buffer
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|  * @buf:		the buffer to search
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|  * @len:		the length of buffer to search
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|  * @paglen:	the pagelength
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|  * @td:		search pattern descriptor
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|  *
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|  * Check for a pattern at the given place. Used to search bad block
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|  * tables and good / bad block identifiers. Same as check_pattern, but
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|  * no optional empty check and the pattern is expected to start
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|  * at offset 0.
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|  *
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|  */
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| static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
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| {
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| 	int i;
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| 	uint8_t *p = buf;
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| 
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| 	/* Compare the pattern */
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| 	for (i = 0; i < td->len; i++) {
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| 		if (p[i] != td->pattern[i])
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| 			return -1;
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| 	}
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|         return 0;
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| }
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| 
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| /**
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|  * create_bbt - [GENERIC] Create a bad block table by scanning the device
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|  * @mtd:		MTD device structure
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|  * @buf:		temporary buffer
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|  * @bd:		descriptor for the good/bad block search pattern
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|  * @chip:		create the table for a specific chip, -1 read all chips.
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|  *              Applies only if NAND_BBT_PERCHIP option is set
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|  *
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|  * Create a bad block table by scanning the device
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|  * for the given good/bad block identify pattern
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|  */
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| static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
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| {
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| 	struct onenand_chip *this = mtd->priv;
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| 	struct bbm_info *bbm = this->bbm;
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| 	int i, j, numblocks, len, scanlen;
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| 	int startblock;
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| 	loff_t from;
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| 	size_t readlen;
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| 	struct mtd_oob_ops ops = { };
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| 	int rgn;
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| 
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| 	printk(KERN_INFO "Scanning device for bad blocks\n");
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| 
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| 	len = 2;
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| 
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| 	/* We need only read few bytes from the OOB area */
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| 	scanlen = 0;
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| 	readlen = bd->len;
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| 
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| 	/* chip == -1 case only */
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| 	/* Note that numblocks is 2 * (real numblocks) here;
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| 	 * see i += 2 below as it makses shifting and masking less painful
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| 	 */
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| 	numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
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| 	startblock = 0;
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| 	from = 0;
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| 
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| 	ops.mode = MTD_OPS_PLACE_OOB;
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| 	ops.ooblen = readlen;
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| 	ops.oobbuf = buf;
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| 	ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
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| 
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| 	for (i = startblock; i < numblocks; ) {
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| 		int ret;
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| 
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| 		for (j = 0; j < len; j++) {
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| 			/* No need to read pages fully,
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| 			 * just read required OOB bytes */
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| 			ret = onenand_bbt_read_oob(mtd,
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| 				from + j * this->writesize + bd->offs, &ops);
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| 
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| 			/* If it is a initial bad block, just ignore it */
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| 			if (ret == ONENAND_BBT_READ_FATAL_ERROR)
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| 				return -EIO;
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| 
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| 			if (ret || check_short_pattern(&buf[j * scanlen],
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| 					       scanlen, this->writesize, bd)) {
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| 				bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
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| 				printk(KERN_INFO "OneNAND eraseblock %d is an "
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| 					"initial bad block\n", i >> 1);
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| 				mtd->ecc_stats.badblocks++;
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| 				break;
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| 			}
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| 		}
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| 		i += 2;
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| 
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| 		if (FLEXONENAND(this)) {
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| 			rgn = flexonenand_region(mtd, from);
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| 			from += mtd->eraseregions[rgn].erasesize;
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| 		} else
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| 			from += (1 << bbm->bbt_erase_shift);
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| 	}
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| 
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| 	return 0;
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| }
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| 
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| 
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| /**
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|  * onenand_memory_bbt - [GENERIC] create a memory based bad block table
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|  * @mtd:		MTD device structure
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|  * @bd:		descriptor for the good/bad block search pattern
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|  *
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|  * The function creates a memory based bbt by scanning the device
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|  * for manufacturer / software marked good / bad blocks
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|  */
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| static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
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| {
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| 	struct onenand_chip *this = mtd->priv;
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| 
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| 	return create_bbt(mtd, this->page_buf, bd, -1);
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| }
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| 
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| /**
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|  * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
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|  * @mtd:		MTD device structure
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|  * @offs:		offset in the device
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|  * @allowbbt:	allow access to bad block table region
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|  */
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| static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
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| {
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| 	struct onenand_chip *this = mtd->priv;
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| 	struct bbm_info *bbm = this->bbm;
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| 	int block;
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| 	uint8_t res;
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| 
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| 	/* Get block number * 2 */
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| 	block = (int) (onenand_block(this, offs) << 1);
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| 	res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
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| 
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| 	pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
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| 		(unsigned int) offs, block >> 1, res);
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| 
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| 	switch ((int) res) {
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| 	case 0x00:	return 0;
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| 	case 0x01:	return 1;
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| 	case 0x02:	return allowbbt ? 0 : 1;
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| 	}
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| 
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| 	return 1;
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| }
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| 
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| /**
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|  * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
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|  * @mtd:		MTD device structure
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|  * @bd:		descriptor for the good/bad block search pattern
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|  *
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|  * The function checks, if a bad block table(s) is/are already
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|  * available. If not it scans the device for manufacturer
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|  * marked good / bad blocks and writes the bad block table(s) to
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|  * the selected place.
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|  *
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|  * The bad block table memory is allocated here. It is freed
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|  * by the onenand_release function.
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|  *
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|  */
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| static int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
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| {
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| 	struct onenand_chip *this = mtd->priv;
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| 	struct bbm_info *bbm = this->bbm;
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| 	int len, ret = 0;
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| 
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| 	len = this->chipsize >> (this->erase_shift + 2);
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| 	/* Allocate memory (2bit per block) and clear the memory bad block table */
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| 	bbm->bbt = kzalloc(len, GFP_KERNEL);
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| 	if (!bbm->bbt)
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| 		return -ENOMEM;
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| 
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| 	/* Set erase shift */
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| 	bbm->bbt_erase_shift = this->erase_shift;
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| 
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| 	if (!bbm->isbad_bbt)
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| 		bbm->isbad_bbt = onenand_isbad_bbt;
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| 
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| 	/* Scan the device to build a memory based bad block table */
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| 	if ((ret = onenand_memory_bbt(mtd, bd))) {
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| 		printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
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| 		kfree(bbm->bbt);
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| 		bbm->bbt = NULL;
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| 	}
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| 
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| 	return ret;
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| }
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| 
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| /*
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|  * Define some generic bad / good block scan pattern which are used
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|  * while scanning a device for factory marked good / bad blocks.
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|  */
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| static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
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| 
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| static struct nand_bbt_descr largepage_memorybased = {
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| 	.options = 0,
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| 	.offs = 0,
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| 	.len = 2,
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| 	.pattern = scan_ff_pattern,
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| };
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| 
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| /**
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|  * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
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|  * @mtd:		MTD device structure
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|  *
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|  * This function selects the default bad block table
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|  * support for the device and calls the onenand_scan_bbt function
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|  */
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| int onenand_default_bbt(struct mtd_info *mtd)
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| {
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| 	struct onenand_chip *this = mtd->priv;
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| 	struct bbm_info *bbm;
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| 
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| 	this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);
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| 	if (!this->bbm)
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| 		return -ENOMEM;
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| 
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| 	bbm = this->bbm;
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| 
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| 	/* 1KB page has same configuration as 2KB page */
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| 	if (!bbm->badblock_pattern)
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| 		bbm->badblock_pattern = &largepage_memorybased;
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| 
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| 	return onenand_scan_bbt(mtd, bbm->badblock_pattern);
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| }
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