Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1491 insertions, 0 deletions

diff --git a/drivers/mtd/nand/raw/nand_bbt.c b/drivers/mtd/nand/raw/nand_bbt.c
new file mode 100644
index 000000000..e4664fa6f
--- /dev/null
+++ b/drivers/mtd/nand/raw/nand_bbt.c
@@ -0,0 +1,1491 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Overview:
+ *   Bad block table support for the NAND driver
+ *
+ *  Copyright © 2004 Thomas Gleixner (tglx@linutronix.de)
+ *
+ * Description:
+ *
+ * When nand_scan_bbt is called, then it tries to find the bad block table
+ * depending on the options in the BBT descriptor(s). If no flash based BBT
+ * (NAND_BBT_USE_FLASH) is specified then the device is scanned for factory
+ * marked good / bad blocks. This information is used to create a memory BBT.
+ * Once a new bad block is discovered then the "factory" information is updated
+ * on the device.
+ * If a flash based BBT is specified then the function first tries to find the
+ * BBT on flash. If a BBT is found then the contents are read and the memory
+ * based BBT is created. If a mirrored BBT is selected then the mirror is
+ * searched too and the versions are compared. If the mirror has a greater
+ * version number, then the mirror BBT is used to build the memory based BBT.
+ * If the tables are not versioned, then we "or" the bad block information.
+ * If one of the BBTs is out of date or does not exist it is (re)created.
+ * If no BBT exists at all then the device is scanned for factory marked
+ * good / bad blocks and the bad block tables are created.
+ *
+ * For manufacturer created BBTs like the one found on M-SYS DOC devices
+ * the BBT is searched and read but never created
+ *
+ * The auto generated bad block table is located in the last good blocks
+ * of the device. The table is mirrored, so it can be updated eventually.
+ * The table is marked in the OOB area with an ident pattern and a version
+ * number which indicates which of both tables is more up to date. If the NAND
+ * controller needs the complete OOB area for the ECC information then the
+ * option NAND_BBT_NO_OOB should be used (along with NAND_BBT_USE_FLASH, of
+ * course): it moves the ident pattern and the version byte into the data area
+ * and the OOB area will remain untouched.
+ *
+ * The table uses 2 bits per block
+ * 11b:		block is good
+ * 00b:		block is factory marked bad
+ * 01b, 10b:	block is marked bad due to wear
+ *
+ * The memory bad block table uses the following scheme:
+ * 00b:		block is good
+ * 01b:		block is marked bad due to wear
+ * 10b:		block is reserved (to protect the bbt area)
+ * 11b:		block is factory marked bad
+ *
+ * Multichip devices like DOC store the bad block info per floor.
+ *
+ * Following assumptions are made:
+ * - bbts start at a page boundary, if autolocated on a block boundary
+ * - the space necessary for a bbt in FLASH does not exceed a block boundary
+ */
+
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/bbm.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/vmalloc.h>
+#include <linux/export.h>
+#include <linux/string.h>
+
+#include "internals.h"
+
+#define BBT_BLOCK_GOOD		0x00
+#define BBT_BLOCK_WORN		0x01
+#define BBT_BLOCK_RESERVED	0x02
+#define BBT_BLOCK_FACTORY_BAD	0x03
+
+#define BBT_ENTRY_MASK		0x03
+#define BBT_ENTRY_SHIFT		2
+
+static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
+{
+	uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
+	entry >>= (block & BBT_ENTRY_MASK) * 2;
+	return entry & BBT_ENTRY_MASK;
+}
+
+static inline void bbt_mark_entry(struct nand_chip *chip, int block,
+		uint8_t mark)
+{
+	uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);
+	chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;
+}
+
+static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
+{
+	if (memcmp(buf, td->pattern, td->len))
+		return -1;
+	return 0;
+}
+
+/**
+ * check_pattern - [GENERIC] check if a pattern is in the buffer
+ * @buf: the buffer to search
+ * @len: the length of buffer to search
+ * @paglen: the pagelength
+ * @td: search pattern descriptor
+ *
+ * Check for a pattern at the given place. Used to search bad block tables and
+ * good / bad block identifiers.
+ */
+static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
+{
+	if (td->options & NAND_BBT_NO_OOB)
+		return check_pattern_no_oob(buf, td);
+
+	/* Compare the pattern */
+	if (memcmp(buf + paglen + td->offs, td->pattern, td->len))
+		return -1;
+
+	return 0;
+}
+
+/**
+ * check_short_pattern - [GENERIC] check if a pattern is in the buffer
+ * @buf: the buffer to search
+ * @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.
+ */
+static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
+{
+	/* Compare the pattern */
+	if (memcmp(buf + td->offs, td->pattern, td->len))
+		return -1;
+	return 0;
+}
+
+/**
+ * add_marker_len - compute the length of the marker in data area
+ * @td: BBT descriptor used for computation
+ *
+ * The length will be 0 if the marker is located in OOB area.
+ */
+static u32 add_marker_len(struct nand_bbt_descr *td)
+{
+	u32 len;
+
+	if (!(td->options & NAND_BBT_NO_OOB))
+		return 0;
+
+	len = td->len;
+	if (td->options & NAND_BBT_VERSION)
+		len++;
+	return len;
+}
+
+/**
+ * read_bbt - [GENERIC] Read the bad block table starting from page
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @page: the starting page
+ * @num: the number of bbt descriptors to read
+ * @td: the bbt describtion table
+ * @offs: block number offset in the table
+ *
+ * Read the bad block table starting from page.
+ */
+static int read_bbt(struct nand_chip *this, uint8_t *buf, int page, int num,
+		    struct nand_bbt_descr *td, int offs)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	int res, ret = 0, i, j, act = 0;
+	size_t retlen, len, totlen;
+	loff_t from;
+	int bits = td->options & NAND_BBT_NRBITS_MSK;
+	uint8_t msk = (uint8_t)((1 << bits) - 1);
+	u32 marker_len;
+	int reserved_block_code = td->reserved_block_code;
+
+	totlen = (num * bits) >> 3;
+	marker_len = add_marker_len(td);
+	from = ((loff_t)page) << this->page_shift;
+
+	while (totlen) {
+		len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
+		if (marker_len) {
+			/*
+			 * In case the BBT marker is not in the OOB area it
+			 * will be just in the first page.
+			 */
+			len -= marker_len;
+			from += marker_len;
+			marker_len = 0;
+		}
+		res = mtd_read(mtd, from, len, &retlen, buf);
+		if (res < 0) {
+			if (mtd_is_eccerr(res)) {
+				pr_info("nand_bbt: ECC error in BBT at 0x%012llx\n",
+					from & ~mtd->writesize);
+				return res;
+			} else if (mtd_is_bitflip(res)) {
+				pr_info("nand_bbt: corrected error in BBT at 0x%012llx\n",
+					from & ~mtd->writesize);
+				ret = res;
+			} else {
+				pr_info("nand_bbt: error reading BBT\n");
+				return res;
+			}
+		}
+
+		/* Analyse data */
+		for (i = 0; i < len; i++) {
+			uint8_t dat = buf[i];
+			for (j = 0; j < 8; j += bits, act++) {
+				uint8_t tmp = (dat >> j) & msk;
+				if (tmp == msk)
+					continue;
+				if (reserved_block_code && (tmp == reserved_block_code)) {
+					pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
+						 (loff_t)(offs + act) <<
+						 this->bbt_erase_shift);
+					bbt_mark_entry(this, offs + act,
+							BBT_BLOCK_RESERVED);
+					mtd->ecc_stats.bbtblocks++;
+					continue;
+				}
+				/*
+				 * Leave it for now, if it's matured we can
+				 * move this message to pr_debug.
+				 */
+				pr_info("nand_read_bbt: bad block at 0x%012llx\n",
+					 (loff_t)(offs + act) <<
+					 this->bbt_erase_shift);
+				/* Factory marked bad or worn out? */
+				if (tmp == 0)
+					bbt_mark_entry(this, offs + act,
+							BBT_BLOCK_FACTORY_BAD);
+				else
+					bbt_mark_entry(this, offs + act,
+							BBT_BLOCK_WORN);
+				mtd->ecc_stats.badblocks++;
+			}
+		}
+		totlen -= len;
+		from += len;
+	}
+	return ret;
+}
+
+/**
+ * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @td: descriptor for the bad block table
+ * @chip: read the table for a specific chip, -1 read all chips; applies only if
+ *        NAND_BBT_PERCHIP option is set
+ *
+ * Read the bad block table for all chips starting at a given page. We assume
+ * that the bbt bits are in consecutive order.
+ */
+static int read_abs_bbt(struct nand_chip *this, uint8_t *buf,
+			struct nand_bbt_descr *td, int chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	u64 targetsize = nanddev_target_size(&this->base);
+	int res = 0, i;
+
+	if (td->options & NAND_BBT_PERCHIP) {
+		int offs = 0;
+		for (i = 0; i < nanddev_ntargets(&this->base); i++) {
+			if (chip == -1 || chip == i)
+				res = read_bbt(this, buf, td->pages[i],
+					targetsize >> this->bbt_erase_shift,
+					td, offs);
+			if (res)
+				return res;
+			offs += targetsize >> this->bbt_erase_shift;
+		}
+	} else {
+		res = read_bbt(this, buf, td->pages[0],
+				mtd->size >> this->bbt_erase_shift, td, 0);
+		if (res)
+			return res;
+	}
+	return 0;
+}
+
+/* BBT marker is in the first page, no OOB */
+static int scan_read_data(struct nand_chip *this, uint8_t *buf, loff_t offs,
+			  struct nand_bbt_descr *td)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	size_t retlen;
+	size_t len;
+
+	len = td->len;
+	if (td->options & NAND_BBT_VERSION)
+		len++;
+
+	return mtd_read(mtd, offs, len, &retlen, buf);
+}
+
+/**
+ * scan_read_oob - [GENERIC] Scan data+OOB region to buffer
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @offs: offset at which to scan
+ * @len: length of data region to read
+ *
+ * Scan read data from data+OOB. May traverse multiple pages, interleaving
+ * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest"
+ * ECC condition (error or bitflip). May quit on the first (non-ECC) error.
+ */
+static int scan_read_oob(struct nand_chip *this, uint8_t *buf, loff_t offs,
+			 size_t len)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	struct mtd_oob_ops ops = { };
+	int res, ret = 0;
+
+	ops.mode = MTD_OPS_PLACE_OOB;
+	ops.ooboffs = 0;
+	ops.ooblen = mtd->oobsize;
+
+	while (len > 0) {
+		ops.datbuf = buf;
+		ops.len = min(len, (size_t)mtd->writesize);
+		ops.oobbuf = buf + ops.len;
+
+		res = mtd_read_oob(mtd, offs, &ops);
+		if (res) {
+			if (!mtd_is_bitflip_or_eccerr(res))
+				return res;
+			else if (mtd_is_eccerr(res) || !ret)
+				ret = res;
+		}
+
+		buf += mtd->oobsize + mtd->writesize;
+		len -= mtd->writesize;
+		offs += mtd->writesize;
+	}
+	return ret;
+}
+
+static int scan_read(struct nand_chip *this, uint8_t *buf, loff_t offs,
+		     size_t len, struct nand_bbt_descr *td)
+{
+	if (td->options & NAND_BBT_NO_OOB)
+		return scan_read_data(this, buf, offs, td);
+	else
+		return scan_read_oob(this, buf, offs, len);
+}
+
+/* Scan write data with oob to flash */
+static int scan_write_bbt(struct nand_chip *this, loff_t offs, size_t len,
+			  uint8_t *buf, uint8_t *oob)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	struct mtd_oob_ops ops = { };
+
+	ops.mode = MTD_OPS_PLACE_OOB;
+	ops.ooboffs = 0;
+	ops.ooblen = mtd->oobsize;
+	ops.datbuf = buf;
+	ops.oobbuf = oob;
+	ops.len = len;
+
+	return mtd_write_oob(mtd, offs, &ops);
+}
+
+static u32 bbt_get_ver_offs(struct nand_chip *this, struct nand_bbt_descr *td)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	u32 ver_offs = td->veroffs;
+
+	if (!(td->options & NAND_BBT_NO_OOB))
+		ver_offs += mtd->writesize;
+	return ver_offs;
+}
+
+/**
+ * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @td: descriptor for the bad block table
+ * @md:	descriptor for the bad block table mirror
+ *
+ * Read the bad block table(s) for all chips starting at a given page. We
+ * assume that the bbt bits are in consecutive order.
+ */
+static void read_abs_bbts(struct nand_chip *this, uint8_t *buf,
+			  struct nand_bbt_descr *td, struct nand_bbt_descr *md)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+
+	/* Read the primary version, if available */
+	if (td->options & NAND_BBT_VERSION) {
+		scan_read(this, buf, (loff_t)td->pages[0] << this->page_shift,
+			  mtd->writesize, td);
+		td->version[0] = buf[bbt_get_ver_offs(this, td)];
+		pr_info("Bad block table at page %d, version 0x%02X\n",
+			 td->pages[0], td->version[0]);
+	}
+
+	/* Read the mirror version, if available */
+	if (md && (md->options & NAND_BBT_VERSION)) {
+		scan_read(this, buf, (loff_t)md->pages[0] << this->page_shift,
+			  mtd->writesize, md);
+		md->version[0] = buf[bbt_get_ver_offs(this, md)];
+		pr_info("Bad block table at page %d, version 0x%02X\n",
+			 md->pages[0], md->version[0]);
+	}
+}
+
+/* Scan a given block partially */
+static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
+			   loff_t offs, uint8_t *buf)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+
+	struct mtd_oob_ops ops = { };
+	int ret, page_offset;
+
+	ops.ooblen = mtd->oobsize;
+	ops.oobbuf = buf;
+	ops.ooboffs = 0;
+	ops.datbuf = NULL;
+	ops.mode = MTD_OPS_PLACE_OOB;
+
+	page_offset = nand_bbm_get_next_page(this, 0);
+
+	while (page_offset >= 0) {
+		/*
+		 * Read the full oob until read_oob is fixed to handle single
+		 * byte reads for 16 bit buswidth.
+		 */
+		ret = mtd_read_oob(mtd, offs + (page_offset * mtd->writesize),
+				   &ops);
+		/* Ignore ECC errors when checking for BBM */
+		if (ret && !mtd_is_bitflip_or_eccerr(ret))
+			return ret;
+
+		if (check_short_pattern(buf, bd))
+			return 1;
+
+		page_offset = nand_bbm_get_next_page(this, page_offset + 1);
+	}
+
+	return 0;
+}
+
+/* Check if a potential BBT block is marked as bad */
+static int bbt_block_checkbad(struct nand_chip *this, struct nand_bbt_descr *td,
+			      loff_t offs, uint8_t *buf)
+{
+	struct nand_bbt_descr *bd = this->badblock_pattern;
+
+	/*
+	 * No need to check for a bad BBT block if the BBM area overlaps with
+	 * the bad block table marker area in OOB since writing a BBM here
+	 * invalidates the bad block table marker anyway.
+	 */
+	if (!(td->options & NAND_BBT_NO_OOB) &&
+	    td->offs >= bd->offs && td->offs < bd->offs + bd->len)
+		return 0;
+
+	/*
+	 * There is no point in checking for a bad block marker if writing
+	 * such marker is not supported
+	 */
+	if (this->bbt_options & NAND_BBT_NO_OOB_BBM ||
+	    this->options & NAND_NO_BBM_QUIRK)
+		return 0;
+
+	if (scan_block_fast(this, bd, offs, buf) > 0)
+		return 1;
+
+	return 0;
+}
+
+/**
+ * create_bbt - [GENERIC] Create a bad block table by scanning the device
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @bd: descriptor for the good/bad block search pattern
+ * @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 nand_chip *this, uint8_t *buf,
+		      struct nand_bbt_descr *bd, int chip)
+{
+	u64 targetsize = nanddev_target_size(&this->base);
+	struct mtd_info *mtd = nand_to_mtd(this);
+	int i, numblocks, startblock;
+	loff_t from;
+
+	pr_info("Scanning device for bad blocks\n");
+
+	if (chip == -1) {
+		numblocks = mtd->size >> this->bbt_erase_shift;
+		startblock = 0;
+		from = 0;
+	} else {
+		if (chip >= nanddev_ntargets(&this->base)) {
+			pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
+			        chip + 1, nanddev_ntargets(&this->base));
+			return -EINVAL;
+		}
+		numblocks = targetsize >> this->bbt_erase_shift;
+		startblock = chip * numblocks;
+		numblocks += startblock;
+		from = (loff_t)startblock << this->bbt_erase_shift;
+	}
+
+	for (i = startblock; i < numblocks; i++) {
+		int ret;
+
+		BUG_ON(bd->options & NAND_BBT_NO_OOB);
+
+		ret = scan_block_fast(this, bd, from, buf);
+		if (ret < 0)
+			return ret;
+
+		if (ret) {
+			bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
+			pr_warn("Bad eraseblock %d at 0x%012llx\n",
+				i, (unsigned long long)from);
+			mtd->ecc_stats.badblocks++;
+		}
+
+		from += (1 << this->bbt_erase_shift);
+	}
+	return 0;
+}
+
+/**
+ * search_bbt - [GENERIC] scan the device for a specific bad block table
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @td: descriptor for the bad block table
+ *
+ * Read the bad block table by searching for a given ident pattern. Search is
+ * preformed either from the beginning up or from the end of the device
+ * downwards. The search starts always at the start of a block. If the option
+ * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
+ * the bad block information of this chip. This is necessary to provide support
+ * for certain DOC devices.
+ *
+ * The bbt ident pattern resides in the oob area of the first page in a block.
+ */
+static int search_bbt(struct nand_chip *this, uint8_t *buf,
+		      struct nand_bbt_descr *td)
+{
+	u64 targetsize = nanddev_target_size(&this->base);
+	struct mtd_info *mtd = nand_to_mtd(this);
+	int i, chips;
+	int startblock, block, dir;
+	int scanlen = mtd->writesize + mtd->oobsize;
+	int bbtblocks;
+	int blocktopage = this->bbt_erase_shift - this->page_shift;
+
+	/* Search direction top -> down? */
+	if (td->options & NAND_BBT_LASTBLOCK) {
+		startblock = (mtd->size >> this->bbt_erase_shift) - 1;
+		dir = -1;
+	} else {
+		startblock = 0;
+		dir = 1;
+	}
+
+	/* Do we have a bbt per chip? */
+	if (td->options & NAND_BBT_PERCHIP) {
+		chips = nanddev_ntargets(&this->base);
+		bbtblocks = targetsize >> this->bbt_erase_shift;
+		startblock &= bbtblocks - 1;
+	} else {
+		chips = 1;
+		bbtblocks = mtd->size >> this->bbt_erase_shift;
+	}
+
+	for (i = 0; i < chips; i++) {
+		/* Reset version information */
+		td->version[i] = 0;
+		td->pages[i] = -1;
+		/* Scan the maximum number of blocks */
+		for (block = 0; block < td->maxblocks; block++) {
+
+			int actblock = startblock + dir * block;
+			loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
+
+			/* Check if block is marked bad */
+			if (bbt_block_checkbad(this, td, offs, buf))
+				continue;
+
+			/* Read first page */
+			scan_read(this, buf, offs, mtd->writesize, td);
+			if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
+				td->pages[i] = actblock << blocktopage;
+				if (td->options & NAND_BBT_VERSION) {
+					offs = bbt_get_ver_offs(this, td);
+					td->version[i] = buf[offs];
+				}
+				break;
+			}
+		}
+		startblock += targetsize >> this->bbt_erase_shift;
+	}
+	/* Check, if we found a bbt for each requested chip */
+	for (i = 0; i < chips; i++) {
+		if (td->pages[i] == -1)
+			pr_warn("Bad block table not found for chip %d\n", i);
+		else
+			pr_info("Bad block table found at page %d, version 0x%02X\n",
+				td->pages[i], td->version[i]);
+	}
+	return 0;
+}
+
+/**
+ * search_read_bbts - [GENERIC] scan the device for bad block table(s)
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @td: descriptor for the bad block table
+ * @md: descriptor for the bad block table mirror
+ *
+ * Search and read the bad block table(s).
+ */
+static void search_read_bbts(struct nand_chip *this, uint8_t *buf,
+			     struct nand_bbt_descr *td,
+			     struct nand_bbt_descr *md)
+{
+	/* Search the primary table */
+	search_bbt(this, buf, td);
+
+	/* Search the mirror table */
+	if (md)
+		search_bbt(this, buf, md);
+}
+
+/**
+ * get_bbt_block - Get the first valid eraseblock suitable to store a BBT
+ * @this: the NAND device
+ * @td: the BBT description
+ * @md: the mirror BBT descriptor
+ * @chip: the CHIP selector
+ *
+ * This functions returns a positive block number pointing a valid eraseblock
+ * suitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC if
+ * all blocks are already used of marked bad. If td->pages[chip] was already
+ * pointing to a valid block we re-use it, otherwise we search for the next
+ * valid one.
+ */
+static int get_bbt_block(struct nand_chip *this, struct nand_bbt_descr *td,
+			 struct nand_bbt_descr *md, int chip)
+{
+	u64 targetsize = nanddev_target_size(&this->base);
+	int startblock, dir, page, numblocks, i;
+
+	/*
+	 * There was already a version of the table, reuse the page. This
+	 * applies for absolute placement too, as we have the page number in
+	 * td->pages.
+	 */
+	if (td->pages[chip] != -1)
+		return td->pages[chip] >>
+				(this->bbt_erase_shift - this->page_shift);
+
+	numblocks = (int)(targetsize >> this->bbt_erase_shift);
+	if (!(td->options & NAND_BBT_PERCHIP))
+		numblocks *= nanddev_ntargets(&this->base);
+
+	/*
+	 * Automatic placement of the bad block table. Search direction
+	 * top -> down?
+	 */
+	if (td->options & NAND_BBT_LASTBLOCK) {
+		startblock = numblocks * (chip + 1) - 1;
+		dir = -1;
+	} else {
+		startblock = chip * numblocks;
+		dir = 1;
+	}
+
+	for (i = 0; i < td->maxblocks; i++) {
+		int block = startblock + dir * i;
+
+		/* Check, if the block is bad */
+		switch (bbt_get_entry(this, block)) {
+		case BBT_BLOCK_WORN:
+		case BBT_BLOCK_FACTORY_BAD:
+			continue;
+		}
+
+		page = block << (this->bbt_erase_shift - this->page_shift);
+
+		/* Check, if the block is used by the mirror table */
+		if (!md || md->pages[chip] != page)
+			return block;
+	}
+
+	return -ENOSPC;
+}
+
+/**
+ * mark_bbt_block_bad - Mark one of the block reserved for BBT bad
+ * @this: the NAND device
+ * @td: the BBT description
+ * @chip: the CHIP selector
+ * @block: the BBT block to mark
+ *
+ * Blocks reserved for BBT can become bad. This functions is an helper to mark
+ * such blocks as bad. It takes care of updating the in-memory BBT, marking the
+ * block as bad using a bad block marker and invalidating the associated
+ * td->pages[] entry.
+ */
+static void mark_bbt_block_bad(struct nand_chip *this,
+			       struct nand_bbt_descr *td,
+			       int chip, int block)
+{
+	loff_t to;
+	int res;
+
+	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
+
+	to = (loff_t)block << this->bbt_erase_shift;
+	res = nand_markbad_bbm(this, to);
+	if (res)
+		pr_warn("nand_bbt: error %d while marking block %d bad\n",
+			res, block);
+
+	td->pages[chip] = -1;
+}
+
+/**
+ * write_bbt - [GENERIC] (Re)write the bad block table
+ * @this: NAND chip object
+ * @buf: temporary buffer
+ * @td: descriptor for the bad block table
+ * @md: descriptor for the bad block table mirror
+ * @chipsel: selector for a specific chip, -1 for all
+ *
+ * (Re)write the bad block table.
+ */
+static int write_bbt(struct nand_chip *this, uint8_t *buf,
+		     struct nand_bbt_descr *td, struct nand_bbt_descr *md,
+		     int chipsel)
+{
+	u64 targetsize = nanddev_target_size(&this->base);
+	struct mtd_info *mtd = nand_to_mtd(this);
+	struct erase_info einfo;
+	int i, res, chip = 0;
+	int bits, page, offs, numblocks, sft, sftmsk;
+	int nrchips, pageoffs, ooboffs;
+	uint8_t msk[4];
+	uint8_t rcode = td->reserved_block_code;
+	size_t retlen, len = 0;
+	loff_t to;
+	struct mtd_oob_ops ops = { };
+
+	ops.ooblen = mtd->oobsize;
+	ops.ooboffs = 0;
+	ops.datbuf = NULL;
+	ops.mode = MTD_OPS_PLACE_OOB;
+
+	if (!rcode)
+		rcode = 0xff;
+	/* Write bad block table per chip rather than per device? */
+	if (td->options & NAND_BBT_PERCHIP) {
+		numblocks = (int)(targetsize >> this->bbt_erase_shift);
+		/* Full device write or specific chip? */
+		if (chipsel == -1) {
+			nrchips = nanddev_ntargets(&this->base);
+		} else {
+			nrchips = chipsel + 1;
+			chip = chipsel;
+		}
+	} else {
+		numblocks = (int)(mtd->size >> this->bbt_erase_shift);
+		nrchips = 1;
+	}
+
+	/* Loop through the chips */
+	while (chip < nrchips) {
+		int block;
+
+		block = get_bbt_block(this, td, md, chip);
+		if (block < 0) {
+			pr_err("No space left to write bad block table\n");
+			res = block;
+			goto outerr;
+		}
+
+		/*
+		 * get_bbt_block() returns a block number, shift the value to
+		 * get a page number.
+		 */
+		page = block << (this->bbt_erase_shift - this->page_shift);
+
+		/* Set up shift count and masks for the flash table */
+		bits = td->options & NAND_BBT_NRBITS_MSK;
+		msk[2] = ~rcode;
+		switch (bits) {
+		case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
+			msk[3] = 0x01;
+			break;
+		case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
+			msk[3] = 0x03;
+			break;
+		case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
+			msk[3] = 0x0f;
+			break;
+		case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
+			msk[3] = 0xff;
+			break;
+		default: return -EINVAL;
+		}
+
+		to = ((loff_t)page) << this->page_shift;
+
+		/* Must we save the block contents? */
+		if (td->options & NAND_BBT_SAVECONTENT) {
+			/* Make it block aligned */
+			to &= ~(((loff_t)1 << this->bbt_erase_shift) - 1);
+			len = 1 << this->bbt_erase_shift;
+			res = mtd_read(mtd, to, len, &retlen, buf);
+			if (res < 0) {
+				if (retlen != len) {
+					pr_info("nand_bbt: error reading block for writing the bad block table\n");
+					return res;
+				}
+				pr_warn("nand_bbt: ECC error while reading block for writing bad block table\n");
+			}
+			/* Read oob data */
+			ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
+			ops.oobbuf = &buf[len];
+			res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
+			if (res < 0 || ops.oobretlen != ops.ooblen)
+				goto outerr;
+
+			/* Calc the byte offset in the buffer */
+			pageoffs = page - (int)(to >> this->page_shift);
+			offs = pageoffs << this->page_shift;
+			/* Preset the bbt area with 0xff */
+			memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
+			ooboffs = len + (pageoffs * mtd->oobsize);
+
+		} else if (td->options & NAND_BBT_NO_OOB) {
+			ooboffs = 0;
+			offs = td->len;
+			/* The version byte */
+			if (td->options & NAND_BBT_VERSION)
+				offs++;
+			/* Calc length */
+			len = (size_t)(numblocks >> sft);
+			len += offs;
+			/* Make it page aligned! */
+			len = ALIGN(len, mtd->writesize);
+			/* Preset the buffer with 0xff */
+			memset(buf, 0xff, len);
+			/* Pattern is located at the begin of first page */
+			memcpy(buf, td->pattern, td->len);
+		} else {
+			/* Calc length */
+			len = (size_t)(numblocks >> sft);
+			/* Make it page aligned! */
+			len = ALIGN(len, mtd->writesize);
+			/* Preset the buffer with 0xff */
+			memset(buf, 0xff, len +
+			       (len >> this->page_shift)* mtd->oobsize);
+			offs = 0;
+			ooboffs = len;
+			/* Pattern is located in oob area of first page */
+			memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
+		}
+
+		if (td->options & NAND_BBT_VERSION)
+			buf[ooboffs + td->veroffs] = td->version[chip];
+
+		/* Walk through the memory table */
+		for (i = 0; i < numblocks; i++) {
+			uint8_t dat;
+			int sftcnt = (i << (3 - sft)) & sftmsk;
+			dat = bbt_get_entry(this, chip * numblocks + i);
+			/* Do not store the reserved bbt blocks! */
+			buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
+		}
+
+		memset(&einfo, 0, sizeof(einfo));
+		einfo.addr = to;
+		einfo.len = 1 << this->bbt_erase_shift;
+		res = nand_erase_nand(this, &einfo, 1);
+		if (res < 0) {
+			pr_warn("nand_bbt: error while erasing BBT block %d\n",
+				res);
+			mark_bbt_block_bad(this, td, chip, block);
+			continue;
+		}
+
+		res = scan_write_bbt(this, to, len, buf,
+				     td->options & NAND_BBT_NO_OOB ?
+				     NULL : &buf[len]);
+		if (res < 0) {
+			pr_warn("nand_bbt: error while writing BBT block %d\n",
+				res);
+			mark_bbt_block_bad(this, td, chip, block);
+			continue;
+		}
+
+		pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
+			 (unsigned long long)to, td->version[chip]);
+
+		/* Mark it as used */
+		td->pages[chip++] = page;
+	}
+	return 0;
+
+ outerr:
+	pr_warn("nand_bbt: error while writing bad block table %d\n", res);
+	return res;
+}
+
+/**
+ * nand_memory_bbt - [GENERIC] create a memory based bad block table
+ * @this: NAND chip object
+ * @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 nand_memory_bbt(struct nand_chip *this,
+				  struct nand_bbt_descr *bd)
+{
+	u8 *pagebuf = nand_get_data_buf(this);
+
+	return create_bbt(this, pagebuf, bd, -1);
+}
+
+/**
+ * check_create - [GENERIC] create and write bbt(s) if necessary
+ * @this: the NAND device
+ * @buf: temporary buffer
+ * @bd: descriptor for the good/bad block search pattern
+ *
+ * The function checks the results of the previous call to read_bbt and creates
+ * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
+ * for the chip/device. Update is necessary if one of the tables is missing or
+ * the version nr. of one table is less than the other.
+ */
+static int check_create(struct nand_chip *this, uint8_t *buf,
+			struct nand_bbt_descr *bd)
+{
+	int i, chips, writeops, create, chipsel, res, res2;
+	struct nand_bbt_descr *td = this->bbt_td;
+	struct nand_bbt_descr *md = this->bbt_md;
+	struct nand_bbt_descr *rd, *rd2;
+
+	/* Do we have a bbt per chip? */
+	if (td->options & NAND_BBT_PERCHIP)
+		chips = nanddev_ntargets(&this->base);
+	else
+		chips = 1;
+
+	for (i = 0; i < chips; i++) {
+		writeops = 0;
+		create = 0;
+		rd = NULL;
+		rd2 = NULL;
+		res = res2 = 0;
+		/* Per chip or per device? */
+		chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
+		/* Mirrored table available? */
+		if (md) {
+			if (td->pages[i] == -1 && md->pages[i] == -1) {
+				create = 1;
+				writeops = 0x03;
+			} else if (td->pages[i] == -1) {
+				rd = md;
+				writeops = 0x01;
+			} else if (md->pages[i] == -1) {
+				rd = td;
+				writeops = 0x02;
+			} else if (td->version[i] == md->version[i]) {
+				rd = td;
+				if (!(td->options & NAND_BBT_VERSION))
+					rd2 = md;
+			} else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
+				rd = td;
+				writeops = 0x02;
+			} else {
+				rd = md;
+				writeops = 0x01;
+			}
+		} else {
+			if (td->pages[i] == -1) {
+				create = 1;
+				writeops = 0x01;
+			} else {
+				rd = td;
+			}
+		}
+
+		if (create) {
+			/* Create the bad block table by scanning the device? */
+			if (!(td->options & NAND_BBT_CREATE))
+				continue;
+
+			/* Create the table in memory by scanning the chip(s) */
+			if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
+				create_bbt(this, buf, bd, chipsel);
+
+			td->version[i] = 1;
+			if (md)
+				md->version[i] = 1;
+		}
+
+		/* Read back first? */
+		if (rd) {
+			res = read_abs_bbt(this, buf, rd, chipsel);
+			if (mtd_is_eccerr(res)) {
+				/* Mark table as invalid */
+				rd->pages[i] = -1;
+				rd->version[i] = 0;
+				i--;
+				continue;
+			}
+		}
+		/* If they weren't versioned, read both */
+		if (rd2) {
+			res2 = read_abs_bbt(this, buf, rd2, chipsel);
+			if (mtd_is_eccerr(res2)) {
+				/* Mark table as invalid */
+				rd2->pages[i] = -1;
+				rd2->version[i] = 0;
+				i--;
+				continue;
+			}
+		}
+
+		/* Scrub the flash table(s)? */
+		if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
+			writeops = 0x03;
+
+		/* Update version numbers before writing */
+		if (md) {
+			td->version[i] = max(td->version[i], md->version[i]);
+			md->version[i] = td->version[i];
+		}
+
+		/* Write the bad block table to the device? */
+		if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
+			res = write_bbt(this, buf, td, md, chipsel);
+			if (res < 0)
+				return res;
+		}
+
+		/* Write the mirror bad block table to the device? */
+		if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
+			res = write_bbt(this, buf, md, td, chipsel);
+			if (res < 0)
+				return res;
+		}
+	}
+	return 0;
+}
+
+/**
+ * nand_update_bbt - update bad block table(s)
+ * @this: the NAND device
+ * @offs: the offset of the newly marked block
+ *
+ * The function updates the bad block table(s).
+ */
+static int nand_update_bbt(struct nand_chip *this, loff_t offs)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	int len, res = 0;
+	int chip, chipsel;
+	uint8_t *buf;
+	struct nand_bbt_descr *td = this->bbt_td;
+	struct nand_bbt_descr *md = this->bbt_md;
+
+	if (!this->bbt || !td)
+		return -EINVAL;
+
+	/* Allocate a temporary buffer for one eraseblock incl. oob */
+	len = (1 << this->bbt_erase_shift);
+	len += (len >> this->page_shift) * mtd->oobsize;
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Do we have a bbt per chip? */
+	if (td->options & NAND_BBT_PERCHIP) {
+		chip = (int)(offs >> this->chip_shift);
+		chipsel = chip;
+	} else {
+		chip = 0;
+		chipsel = -1;
+	}
+
+	td->version[chip]++;
+	if (md)
+		md->version[chip]++;
+
+	/* Write the bad block table to the device? */
+	if (td->options & NAND_BBT_WRITE) {
+		res = write_bbt(this, buf, td, md, chipsel);
+		if (res < 0)
+			goto out;
+	}
+	/* Write the mirror bad block table to the device? */
+	if (md && (md->options & NAND_BBT_WRITE)) {
+		res = write_bbt(this, buf, md, td, chipsel);
+	}
+
+ out:
+	kfree(buf);
+	return res;
+}
+
+/**
+ * mark_bbt_region - [GENERIC] mark the bad block table regions
+ * @this: the NAND device
+ * @td: bad block table descriptor
+ *
+ * The bad block table regions are marked as "bad" to prevent accidental
+ * erasures / writes. The regions are identified by the mark 0x02.
+ */
+static void mark_bbt_region(struct nand_chip *this, struct nand_bbt_descr *td)
+{
+	u64 targetsize = nanddev_target_size(&this->base);
+	struct mtd_info *mtd = nand_to_mtd(this);
+	int i, j, chips, block, nrblocks, update;
+	uint8_t oldval;
+
+	/* Do we have a bbt per chip? */
+	if (td->options & NAND_BBT_PERCHIP) {
+		chips = nanddev_ntargets(&this->base);
+		nrblocks = (int)(targetsize >> this->bbt_erase_shift);
+	} else {
+		chips = 1;
+		nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
+	}
+
+	for (i = 0; i < chips; i++) {
+		if ((td->options & NAND_BBT_ABSPAGE) ||
+		    !(td->options & NAND_BBT_WRITE)) {
+			if (td->pages[i] == -1)
+				continue;
+			block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
+			oldval = bbt_get_entry(this, block);
+			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
+			if ((oldval != BBT_BLOCK_RESERVED) &&
+					td->reserved_block_code)
+				nand_update_bbt(this, (loff_t)block <<
+						this->bbt_erase_shift);
+			continue;
+		}
+		update = 0;
+		if (td->options & NAND_BBT_LASTBLOCK)
+			block = ((i + 1) * nrblocks) - td->maxblocks;
+		else
+			block = i * nrblocks;
+		for (j = 0; j < td->maxblocks; j++) {
+			oldval = bbt_get_entry(this, block);
+			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
+			if (oldval != BBT_BLOCK_RESERVED)
+				update = 1;
+			block++;
+		}
+		/*
+		 * If we want reserved blocks to be recorded to flash, and some
+		 * new ones have been marked, then we need to update the stored
+		 * bbts.  This should only happen once.
+		 */
+		if (update && td->reserved_block_code)
+			nand_update_bbt(this, (loff_t)(block - 1) <<
+					this->bbt_erase_shift);
+	}
+}
+
+/**
+ * verify_bbt_descr - verify the bad block description
+ * @this: the NAND device
+ * @bd: the table to verify
+ *
+ * This functions performs a few sanity checks on the bad block description
+ * table.
+ */
+static void verify_bbt_descr(struct nand_chip *this, struct nand_bbt_descr *bd)
+{
+	u64 targetsize = nanddev_target_size(&this->base);
+	struct mtd_info *mtd = nand_to_mtd(this);
+	u32 pattern_len;
+	u32 bits;
+	u32 table_size;
+
+	if (!bd)
+		return;
+
+	pattern_len = bd->len;
+	bits = bd->options & NAND_BBT_NRBITS_MSK;
+
+	BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
+			!(this->bbt_options & NAND_BBT_USE_FLASH));
+	BUG_ON(!bits);
+
+	if (bd->options & NAND_BBT_VERSION)
+		pattern_len++;
+
+	if (bd->options & NAND_BBT_NO_OOB) {
+		BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
+		BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
+		BUG_ON(bd->offs);
+		if (bd->options & NAND_BBT_VERSION)
+			BUG_ON(bd->veroffs != bd->len);
+		BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
+	}
+
+	if (bd->options & NAND_BBT_PERCHIP)
+		table_size = targetsize >> this->bbt_erase_shift;
+	else
+		table_size = mtd->size >> this->bbt_erase_shift;
+	table_size >>= 3;
+	table_size *= bits;
+	if (bd->options & NAND_BBT_NO_OOB)
+		table_size += pattern_len;
+	BUG_ON(table_size > (1 << this->bbt_erase_shift));
+}
+
+/**
+ * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
+ * @this: the NAND device
+ * @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 nand_free_bbt function.
+ */
+static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	int len, res;
+	uint8_t *buf;
+	struct nand_bbt_descr *td = this->bbt_td;
+	struct nand_bbt_descr *md = this->bbt_md;
+
+	len = (mtd->size >> (this->bbt_erase_shift + 2)) ? : 1;
+	/*
+	 * Allocate memory (2bit per block) and clear the memory bad block
+	 * table.
+	 */
+	this->bbt = kzalloc(len, GFP_KERNEL);
+	if (!this->bbt)
+		return -ENOMEM;
+
+	/*
+	 * If no primary table descriptor is given, scan the device to build a
+	 * memory based bad block table.
+	 */
+	if (!td) {
+		if ((res = nand_memory_bbt(this, bd))) {
+			pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
+			goto err_free_bbt;
+		}
+		return 0;
+	}
+	verify_bbt_descr(this, td);
+	verify_bbt_descr(this, md);
+
+	/* Allocate a temporary buffer for one eraseblock incl. oob */
+	len = (1 << this->bbt_erase_shift);
+	len += (len >> this->page_shift) * mtd->oobsize;
+	buf = vmalloc(len);
+	if (!buf) {
+		res = -ENOMEM;
+		goto err_free_bbt;
+	}
+
+	/* Is the bbt at a given page? */
+	if (td->options & NAND_BBT_ABSPAGE) {
+		read_abs_bbts(this, buf, td, md);
+	} else {
+		/* Search the bad block table using a pattern in oob */
+		search_read_bbts(this, buf, td, md);
+	}
+
+	res = check_create(this, buf, bd);
+	if (res)
+		goto err_free_buf;
+
+	/* Prevent the bbt regions from erasing / writing */
+	mark_bbt_region(this, td);
+	if (md)
+		mark_bbt_region(this, md);
+
+	vfree(buf);
+	return 0;
+
+err_free_buf:
+	vfree(buf);
+err_free_bbt:
+	kfree(this->bbt);
+	this->bbt = NULL;
+	return res;
+}
+
+/*
+ * 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 };
+
+/* Generic flash bbt descriptors */
+static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
+static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
+
+static struct nand_bbt_descr bbt_main_descr = {
+	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
+	.offs =	8,
+	.len = 4,
+	.veroffs = 12,
+	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
+	.pattern = bbt_pattern
+};
+
+static struct nand_bbt_descr bbt_mirror_descr = {
+	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
+	.offs =	8,
+	.len = 4,
+	.veroffs = 12,
+	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
+	.pattern = mirror_pattern
+};
+
+static struct nand_bbt_descr bbt_main_no_oob_descr = {
+	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
+		| NAND_BBT_NO_OOB,
+	.len = 4,
+	.veroffs = 4,
+	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
+	.pattern = bbt_pattern
+};
+
+static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
+	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
+		| NAND_BBT_NO_OOB,
+	.len = 4,
+	.veroffs = 4,
+	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
+	.pattern = mirror_pattern
+};
+
+#define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
+/**
+ * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
+ * @this: NAND chip to create descriptor for
+ *
+ * This function allocates and initializes a nand_bbt_descr for BBM detection
+ * based on the properties of @this. The new descriptor is stored in
+ * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
+ * passed to this function.
+ */
+static int nand_create_badblock_pattern(struct nand_chip *this)
+{
+	struct nand_bbt_descr *bd;
+	if (this->badblock_pattern) {
+		pr_warn("Bad block pattern already allocated; not replacing\n");
+		return -EINVAL;
+	}
+	bd = kzalloc(sizeof(*bd), GFP_KERNEL);
+	if (!bd)
+		return -ENOMEM;
+	bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
+	bd->offs = this->badblockpos;
+	bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
+	bd->pattern = scan_ff_pattern;
+	bd->options |= NAND_BBT_DYNAMICSTRUCT;
+	this->badblock_pattern = bd;
+	return 0;
+}
+
+/**
+ * nand_create_bbt - [NAND Interface] Select a default bad block table for the device
+ * @this: NAND chip object
+ *
+ * This function selects the default bad block table support for the device and
+ * calls the nand_scan_bbt function.
+ */
+int nand_create_bbt(struct nand_chip *this)
+{
+	int ret;
+
+	/* Is a flash based bad block table requested? */
+	if (this->bbt_options & NAND_BBT_USE_FLASH) {
+		/* Use the default pattern descriptors */
+		if (!this->bbt_td) {
+			if (this->bbt_options & NAND_BBT_NO_OOB) {
+				this->bbt_td = &bbt_main_no_oob_descr;
+				this->bbt_md = &bbt_mirror_no_oob_descr;
+			} else {
+				this->bbt_td = &bbt_main_descr;
+				this->bbt_md = &bbt_mirror_descr;
+			}
+		}
+	} else {
+		this->bbt_td = NULL;
+		this->bbt_md = NULL;
+	}
+
+	if (!this->badblock_pattern) {
+		ret = nand_create_badblock_pattern(this);
+		if (ret)
+			return ret;
+	}
+
+	return nand_scan_bbt(this, this->badblock_pattern);
+}
+EXPORT_SYMBOL(nand_create_bbt);
+
+/**
+ * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
+ * @this: NAND chip object
+ * @offs: offset in the device
+ */
+int nand_isreserved_bbt(struct nand_chip *this, loff_t offs)
+{
+	int block;
+
+	block = (int)(offs >> this->bbt_erase_shift);
+	return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;
+}
+
+/**
+ * nand_isbad_bbt - [NAND Interface] Check if a block is bad
+ * @this: NAND chip object
+ * @offs: offset in the device
+ * @allowbbt: allow access to bad block table region
+ */
+int nand_isbad_bbt(struct nand_chip *this, loff_t offs, int allowbbt)
+{
+	int block, res;
+
+	block = (int)(offs >> this->bbt_erase_shift);
+	res = bbt_get_entry(this, block);
+
+	pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
+		 (unsigned int)offs, block, res);
+
+	if (mtd_check_expert_analysis_mode())
+		return 0;
+
+	switch (res) {
+	case BBT_BLOCK_GOOD:
+		return 0;
+	case BBT_BLOCK_WORN:
+		return 1;
+	case BBT_BLOCK_RESERVED:
+		return allowbbt ? 0 : 1;
+	}
+	return 1;
+}
+
+/**
+ * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
+ * @this: NAND chip object
+ * @offs: offset of the bad block
+ */
+int nand_markbad_bbt(struct nand_chip *this, loff_t offs)
+{
+	int block, ret = 0;
+
+	block = (int)(offs >> this->bbt_erase_shift);
+
+	/* Mark bad block in memory */
+	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
+
+	/* Update flash-based bad block table */
+	if (this->bbt_options & NAND_BBT_USE_FLASH)
+		ret = nand_update_bbt(this, offs);
+
+	return ret;
+}