drivers/mtd/onenand/onenand_bbt.c - maze/linux - Git at Google

 /*
  *  linux/drivers/mtd/onenand/onenand_bbt.c
  *
  *  Bad Block Table support for the OneNAND driver
  *
  *  Copyright(c) 2005 Samsung Electronics
  *  Kyungmin Park <kyungmin.park@samsung.com>
  *
  *  Derived from nand_bbt.c
  *
  *  TODO:
  *    Split BBT core and chip specific BBT.
  */

 #include <linux/slab.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/onenand.h>

 /**
  * 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;
 	struct mtd_oob_ops ops;
 	int rgn;

 	printk(KERN_INFO "Scanning device for bad blocks\n");

 	len = 2;

 	/* 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 = this->chipsize >> (bbm->bbt_erase_shift - 1);
 	startblock = 0;
 	from = 0;

 	ops.mode = MTD_OOB_PLACE;
 	ops.ooblen = readlen;
 	ops.oobbuf = buf;
 	ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;

 	for (i = startblock; i < numblocks; ) {
 		int ret;

 		for (j = 0; j < len; j++) {
 			/* No need to read pages fully,
 			 * just read required OOB bytes */
 			ret = onenand_bbt_read_oob(mtd, from + j * mtd->writesize + bd->offs, &ops);

 			/* If it is a initial bad block, just ignore it */
 			if (ret == ONENAND_BBT_READ_FATAL_ERROR)
 				return -EIO;

 			if (ret || 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);
 				mtd->ecc_stats.badblocks++;
 				break;
 			}
 		}
 		i += 2;

 		if (FLEXONENAND(this)) {
 			rgn = flexonenand_region(mtd, from);
 			from += mtd->eraseregions[rgn].erasesize;
 		} else
 			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) (onenand_block(this, offs) << 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 is freed
  * by the onenand_release 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 = this->chipsize >> (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);
	/*
	* linux/drivers/mtd/onenand/onenand_bbt.c
	*
	* Bad Block Table support for the OneNAND driver
	*
	* Copyright(c) 2005 Samsung Electronics
	* Kyungmin Park <kyungmin.park@samsung.com>
	*
	* Derived from nand_bbt.c
	*
	* TODO:
	* Split BBT core and chip specific BBT.
	*/

	#include <linux/slab.h>
	#include <linux/mtd/mtd.h>
	#include <linux/mtd/onenand.h>

	/**
	* 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;
	struct mtd_oob_ops ops;
	int rgn;

	printk(KERN_INFO "Scanning device for bad blocks\n");

	len = 2;

	/* 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 = this->chipsize >> (bbm->bbt_erase_shift - 1);
	startblock = 0;
	from = 0;

	ops.mode = MTD_OOB_PLACE;
	ops.ooblen = readlen;
	ops.oobbuf = buf;
	ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;

	for (i = startblock; i < numblocks; ) {
	int ret;

	for (j = 0; j < len; j++) {
	/* No need to read pages fully,
	* just read required OOB bytes */
	ret = onenand_bbt_read_oob(mtd, from + j * mtd->writesize + bd->offs, &ops);

	/* If it is a initial bad block, just ignore it */
	if (ret == ONENAND_BBT_READ_FATAL_ERROR)
	return -EIO;

	if (ret \|\| 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);
	mtd->ecc_stats.badblocks++;
	break;
	}
	}
	i += 2;

	if (FLEXONENAND(this)) {
	rgn = flexonenand_region(mtd, from);
	from += mtd->eraseregions[rgn].erasesize;
	} else
	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) (onenand_block(this, offs) << 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 is freed
	* by the onenand_release 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 = this->chipsize >> (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);