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-rw-r--r--drivers/mtd/nand/raw/nand_bbt.c1452
1 files changed, 1452 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 000000000000..36092850be2c
--- /dev/null
+++ b/drivers/mtd/nand/raw/nand_bbt.c
@@ -0,0 +1,1452 @@
+/*
+ * Overview:
+ * Bad block table support for the NAND driver
+ *
+ * Copyright © 2004 Thomas Gleixner (tglx@linutronix.de)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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+ * If one of the BBTs is out of date or does not exist it is (re)created.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/mtd/rawnand.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/vmalloc.h>
+#include <linux/export.h>
+#include <linux/string.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 int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
+
+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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf, int page, int num,
+ struct nand_bbt_descr *td, int offs)
+{
+ int res, ret = 0, i, j, act = 0;
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ int res = 0, i;
+
+ if (td->options & NAND_BBT_PERCHIP) {
+ int offs = 0;
+ for (i = 0; i < this->numchips; i++) {
+ if (chip == -1 || chip == i)
+ res = read_bbt(mtd, buf, td->pages[i],
+ this->chipsize >> this->bbt_erase_shift,
+ td, offs);
+ if (res)
+ return res;
+ offs += this->chipsize >> this->bbt_erase_shift;
+ }
+ } else {
+ res = read_bbt(mtd, 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 mtd_info *mtd, uint8_t *buf, loff_t offs,
+ struct nand_bbt_descr *td)
+{
+ 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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf, loff_t offs,
+ size_t len)
+{
+ 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 mtd_info *mtd, 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(mtd, buf, offs, td);
+ else
+ return scan_read_oob(mtd, buf, offs, len);
+}
+
+/* Scan write data with oob to flash */
+static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
+ uint8_t *buf, uint8_t *oob)
+{
+ 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 mtd_info *mtd, struct nand_bbt_descr *td)
+{
+ 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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf,
+ struct nand_bbt_descr *td, struct nand_bbt_descr *md)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+
+ /* Read the primary version, if available */
+ if (td->options & NAND_BBT_VERSION) {
+ scan_read(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
+ mtd->writesize, td);
+ td->version[0] = buf[bbt_get_ver_offs(mtd, 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(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
+ mtd->writesize, md);
+ md->version[0] = buf[bbt_get_ver_offs(mtd, 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 mtd_info *mtd, struct nand_bbt_descr *bd,
+ loff_t offs, uint8_t *buf, int numpages)
+{
+ struct mtd_oob_ops ops;
+ int j, ret;
+
+ ops.ooblen = mtd->oobsize;
+ ops.oobbuf = buf;
+ ops.ooboffs = 0;
+ ops.datbuf = NULL;
+ ops.mode = MTD_OPS_PLACE_OOB;
+
+ for (j = 0; j < numpages; j++) {
+ /*
+ * Read the full oob until read_oob is fixed to handle single
+ * byte reads for 16 bit buswidth.
+ */
+ ret = mtd_read_oob(mtd, offs, &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;
+
+ offs += mtd->writesize;
+ }
+ return 0;
+}
+
+/**
+ * create_bbt - [GENERIC] Create a bad block table by scanning the device
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf,
+ struct nand_bbt_descr *bd, int chip)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ int i, numblocks, numpages;
+ int startblock;
+ loff_t from;
+
+ pr_info("Scanning device for bad blocks\n");
+
+ if (bd->options & NAND_BBT_SCAN2NDPAGE)
+ numpages = 2;
+ else
+ numpages = 1;
+
+ if (chip == -1) {
+ numblocks = mtd->size >> this->bbt_erase_shift;
+ startblock = 0;
+ from = 0;
+ } else {
+ if (chip >= this->numchips) {
+ pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
+ chip + 1, this->numchips);
+ return -EINVAL;
+ }
+ numblocks = this->chipsize >> this->bbt_erase_shift;
+ startblock = chip * numblocks;
+ numblocks += startblock;
+ from = (loff_t)startblock << this->bbt_erase_shift;
+ }
+
+ if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
+ from += mtd->erasesize - (mtd->writesize * numpages);
+
+ for (i = startblock; i < numblocks; i++) {
+ int ret;
+
+ BUG_ON(bd->options & NAND_BBT_NO_OOB);
+
+ ret = scan_block_fast(mtd, bd, from, buf, numpages);
+ 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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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 = this->numchips;
+ bbtblocks = this->chipsize >> 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;
+
+ /* Read first page */
+ scan_read(mtd, 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(mtd, td);
+ td->version[i] = buf[offs];
+ }
+ break;
+ }
+ }
+ startblock += this->chipsize >> 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)
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf,
+ struct nand_bbt_descr *td,
+ struct nand_bbt_descr *md)
+{
+ /* Search the primary table */
+ search_bbt(mtd, buf, td);
+
+ /* Search the mirror table */
+ if (md)
+ search_bbt(mtd, 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)
+{
+ 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)(this->chipsize >> this->bbt_erase_shift);
+ if (!(td->options & NAND_BBT_PERCHIP))
+ numblocks *= this->numchips;
+
+ /*
+ * 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)
+{
+ struct mtd_info *mtd = nand_to_mtd(this);
+ loff_t to;
+ int res;
+
+ bbt_mark_entry(this, block, BBT_BLOCK_WORN);
+
+ to = (loff_t)block << this->bbt_erase_shift;
+ res = this->block_markbad(mtd, 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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf,
+ struct nand_bbt_descr *td, struct nand_bbt_descr *md,
+ int chipsel)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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)(this->chipsize >> this->bbt_erase_shift);
+ /* Full device write or specific chip? */
+ if (chipsel == -1) {
+ nrchips = this->numchips;
+ } 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.mtd = mtd;
+ einfo.addr = to;
+ einfo.len = 1 << this->bbt_erase_shift;
+ res = nand_erase_nand(mtd, &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(mtd, 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
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, struct nand_bbt_descr *bd)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+
+ return create_bbt(mtd, this->data_buf, bd, -1);
+}
+
+/**
+ * check_create - [GENERIC] create and write bbt(s) if necessary
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
+{
+ int i, chips, writeops, create, chipsel, res, res2;
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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 = this->numchips;
+ 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(mtd, buf, bd, chipsel);
+
+ td->version[i] = 1;
+ if (md)
+ md->version[i] = 1;
+ }
+
+ /* Read back first? */
+ if (rd) {
+ res = read_abs_bbt(mtd, 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(mtd, 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(mtd, 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(mtd, buf, md, td, chipsel);
+ if (res < 0)
+ return res;
+ }
+ }
+ return 0;
+}
+
+/**
+ * mark_bbt_regions - [GENERIC] mark the bad block table regions
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, struct nand_bbt_descr *td)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ int i, j, chips, block, nrblocks, update;
+ uint8_t oldval;
+
+ /* Do we have a bbt per chip? */
+ if (td->options & NAND_BBT_PERCHIP) {
+ chips = this->numchips;
+ nrblocks = (int)(this->chipsize >> 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(mtd, (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(mtd, (loff_t)(block - 1) <<
+ this->bbt_erase_shift);
+ }
+}
+
+/**
+ * verify_bbt_descr - verify the bad block description
+ * @mtd: MTD device structure
+ * @bd: the table to verify
+ *
+ * This functions performs a few sanity checks on the bad block description
+ * table.
+ */
+static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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 = this->chipsize >> 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)
+ * @mtd: MTD device structure
+ * @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 mtd_info *mtd, struct nand_bbt_descr *bd)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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 decriptor is given, scan the device to build a
+ * memory based bad block table.
+ */
+ if (!td) {
+ if ((res = nand_memory_bbt(mtd, bd))) {
+ pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
+ goto err;
+ }
+ return 0;
+ }
+ verify_bbt_descr(mtd, td);
+ verify_bbt_descr(mtd, 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;
+ }
+
+ /* Is the bbt at a given page? */
+ if (td->options & NAND_BBT_ABSPAGE) {
+ read_abs_bbts(mtd, buf, td, md);
+ } else {
+ /* Search the bad block table using a pattern in oob */
+ search_read_bbts(mtd, buf, td, md);
+ }
+
+ res = check_create(mtd, buf, bd);
+ if (res)
+ goto err;
+
+ /* Prevent the bbt regions from erasing / writing */
+ mark_bbt_region(mtd, td);
+ if (md)
+ mark_bbt_region(mtd, md);
+
+ vfree(buf);
+ return 0;
+
+err:
+ kfree(this->bbt);
+ this->bbt = NULL;
+ return res;
+}
+
+/**
+ * nand_update_bbt - update bad block table(s)
+ * @mtd: MTD device structure
+ * @offs: the offset of the newly marked block
+ *
+ * The function updates the bad block table(s).
+ */
+static int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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(mtd, 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(mtd, buf, md, td, chipsel);
+ }
+
+ out:
+ kfree(buf);
+ 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_default_bbt - [NAND Interface] Select a default bad block table for the device
+ * @mtd: MTD device structure
+ *
+ * This function selects the default bad block table support for the device and
+ * calls the nand_scan_bbt function.
+ */
+int nand_default_bbt(struct mtd_info *mtd)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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(mtd, this->badblock_pattern);
+}
+
+/**
+ * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
+ * @mtd: MTD device structure
+ * @offs: offset in the device
+ */
+int nand_isreserved_bbt(struct mtd_info *mtd, loff_t offs)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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
+ * @mtd: MTD device structure
+ * @offs: offset in the device
+ * @allowbbt: allow access to bad block table region
+ */
+int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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);
+
+ 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
+ * @mtd: MTD device structure
+ * @offs: offset of the bad block
+ */
+int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ 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(mtd, offs);
+
+ return ret;
+}