1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  Overview:
   4 *   Bad block table support for the NAND driver
   5 *
   6 *  Copyright © 2004 Thomas Gleixner (tglx@linutronix.de)
   7 *
   8 * Description:
   9 *
  10 * When nand_scan_bbt is called, then it tries to find the bad block table
  11 * depending on the options in the BBT descriptor(s). If no flash based BBT
  12 * (NAND_BBT_USE_FLASH) is specified then the device is scanned for factory
  13 * marked good / bad blocks. This information is used to create a memory BBT.
  14 * Once a new bad block is discovered then the "factory" information is updated
  15 * on the device.
  16 * If a flash based BBT is specified then the function first tries to find the
  17 * BBT on flash. If a BBT is found then the contents are read and the memory
  18 * based BBT is created. If a mirrored BBT is selected then the mirror is
  19 * searched too and the versions are compared. If the mirror has a greater
  20 * version number, then the mirror BBT is used to build the memory based BBT.
  21 * If the tables are not versioned, then we "or" the bad block information.
  22 * If one of the BBTs is out of date or does not exist it is (re)created.
  23 * If no BBT exists at all then the device is scanned for factory marked
  24 * good / bad blocks and the bad block tables are created.
  25 *
  26 * For manufacturer created BBTs like the one found on M-SYS DOC devices
  27 * the BBT is searched and read but never created
  28 *
  29 * The auto generated bad block table is located in the last good blocks
  30 * of the device. The table is mirrored, so it can be updated eventually.
  31 * The table is marked in the OOB area with an ident pattern and a version
  32 * number which indicates which of both tables is more up to date. If the NAND
  33 * controller needs the complete OOB area for the ECC information then the
  34 * option NAND_BBT_NO_OOB should be used (along with NAND_BBT_USE_FLASH, of
  35 * course): it moves the ident pattern and the version byte into the data area
  36 * and the OOB area will remain untouched.
  37 *
  38 * The table uses 2 bits per block
  39 * 11b:		block is good
  40 * 00b:		block is factory marked bad
  41 * 01b, 10b:	block is marked bad due to wear
  42 *
  43 * The memory bad block table uses the following scheme:
  44 * 00b:		block is good
  45 * 01b:		block is marked bad due to wear
  46 * 10b:		block is reserved (to protect the bbt area)
  47 * 11b:		block is factory marked bad
  48 *
  49 * Multichip devices like DOC store the bad block info per floor.
  50 *
  51 * Following assumptions are made:
  52 * - bbts start at a page boundary, if autolocated on a block boundary
  53 * - the space necessary for a bbt in FLASH does not exceed a block boundary
  54 */
  55
  56#include <linux/slab.h>
  57#include <linux/types.h>
  58#include <linux/mtd/mtd.h>
  59#include <linux/mtd/bbm.h>
  60#include <linux/bitops.h>
  61#include <linux/delay.h>
  62#include <linux/vmalloc.h>
  63#include <linux/export.h>
  64#include <linux/string.h>
  65
  66#include "internals.h"
  67
  68#define BBT_BLOCK_GOOD		0x00
  69#define BBT_BLOCK_WORN		0x01
  70#define BBT_BLOCK_RESERVED	0x02
  71#define BBT_BLOCK_FACTORY_BAD	0x03
  72
  73#define BBT_ENTRY_MASK		0x03
  74#define BBT_ENTRY_SHIFT		2
  75
  76static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
  77{
  78	uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
  79	entry >>= (block & BBT_ENTRY_MASK) * 2;
  80	return entry & BBT_ENTRY_MASK;
  81}
  82
  83static inline void bbt_mark_entry(struct nand_chip *chip, int block,
  84		uint8_t mark)
  85{
  86	uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);
  87	chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;
  88}
  89
  90static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
  91{
  92	if (memcmp(buf, td->pattern, td->len))
  93		return -1;
  94	return 0;
  95}
  96
  97/**
  98 * check_pattern - [GENERIC] check if a pattern is in the buffer
  99 * @buf: the buffer to search
 100 * @len: the length of buffer to search
 101 * @paglen: the pagelength
 102 * @td: search pattern descriptor
 103 *
 104 * Check for a pattern at the given place. Used to search bad block tables and
 105 * good / bad block identifiers.
 106 */
 107static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
 108{
 109	if (td->options & NAND_BBT_NO_OOB)
 110		return check_pattern_no_oob(buf, td);
 111
 112	/* Compare the pattern */
 113	if (memcmp(buf + paglen + td->offs, td->pattern, td->len))
 114		return -1;
 115
 116	return 0;
 117}
 118
 119/**
 120 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
 121 * @buf: the buffer to search
 122 * @td:	search pattern descriptor
 123 *
 124 * Check for a pattern at the given place. Used to search bad block tables and
 125 * good / bad block identifiers. Same as check_pattern, but no optional empty
 126 * check.
 127 */
 128static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
 129{
 130	/* Compare the pattern */
 131	if (memcmp(buf + td->offs, td->pattern, td->len))
 132		return -1;
 133	return 0;
 134}
 135
 136/**
 137 * add_marker_len - compute the length of the marker in data area
 138 * @td: BBT descriptor used for computation
 139 *
 140 * The length will be 0 if the marker is located in OOB area.
 141 */
 142static u32 add_marker_len(struct nand_bbt_descr *td)
 143{
 144	u32 len;
 145
 146	if (!(td->options & NAND_BBT_NO_OOB))
 147		return 0;
 148
 149	len = td->len;
 150	if (td->options & NAND_BBT_VERSION)
 151		len++;
 152	return len;
 153}
 154
 155/**
 156 * read_bbt - [GENERIC] Read the bad block table starting from page
 157 * @this: NAND chip object
 158 * @buf: temporary buffer
 159 * @page: the starting page
 160 * @num: the number of bbt descriptors to read
 161 * @td: the bbt describtion table
 162 * @offs: block number offset in the table
 163 *
 164 * Read the bad block table starting from page.
 165 */
 166static int read_bbt(struct nand_chip *this, uint8_t *buf, int page, int num,
 167		    struct nand_bbt_descr *td, int offs)
 168{
 169	struct mtd_info *mtd = nand_to_mtd(this);
 170	int res, ret = 0, i, j, act = 0;
 171	size_t retlen, len, totlen;
 172	loff_t from;
 173	int bits = td->options & NAND_BBT_NRBITS_MSK;
 174	uint8_t msk = (uint8_t)((1 << bits) - 1);
 175	u32 marker_len;
 176	int reserved_block_code = td->reserved_block_code;
 177
 178	totlen = (num * bits) >> 3;
 179	marker_len = add_marker_len(td);
 180	from = ((loff_t)page) << this->page_shift;
 181
 182	while (totlen) {
 183		len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
 184		if (marker_len) {
 185			/*
 186			 * In case the BBT marker is not in the OOB area it
 187			 * will be just in the first page.
 188			 */
 189			len -= marker_len;
 190			from += marker_len;
 191			marker_len = 0;
 192		}
 193		res = mtd_read(mtd, from, len, &retlen, buf);
 194		if (res < 0) {
 195			if (mtd_is_eccerr(res)) {
 196				pr_info("nand_bbt: ECC error in BBT at 0x%012llx\n",
 197					from & ~mtd->writesize);
 198				return res;
 199			} else if (mtd_is_bitflip(res)) {
 200				pr_info("nand_bbt: corrected error in BBT at 0x%012llx\n",
 201					from & ~mtd->writesize);
 202				ret = res;
 203			} else {
 204				pr_info("nand_bbt: error reading BBT\n");
 205				return res;
 206			}
 207		}
 208
 209		/* Analyse data */
 210		for (i = 0; i < len; i++) {
 211			uint8_t dat = buf[i];
 212			for (j = 0; j < 8; j += bits, act++) {
 213				uint8_t tmp = (dat >> j) & msk;
 214				if (tmp == msk)
 215					continue;
 216				if (reserved_block_code && (tmp == reserved_block_code)) {
 217					pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
 218						 (loff_t)(offs + act) <<
 219						 this->bbt_erase_shift);
 220					bbt_mark_entry(this, offs + act,
 221							BBT_BLOCK_RESERVED);
 222					mtd->ecc_stats.bbtblocks++;
 223					continue;
 224				}
 225				/*
 226				 * Leave it for now, if it's matured we can
 227				 * move this message to pr_debug.
 228				 */
 229				pr_info("nand_read_bbt: bad block at 0x%012llx\n",
 230					 (loff_t)(offs + act) <<
 231					 this->bbt_erase_shift);
 232				/* Factory marked bad or worn out? */
 233				if (tmp == 0)
 234					bbt_mark_entry(this, offs + act,
 235							BBT_BLOCK_FACTORY_BAD);
 236				else
 237					bbt_mark_entry(this, offs + act,
 238							BBT_BLOCK_WORN);
 239				mtd->ecc_stats.badblocks++;
 240			}
 241		}
 242		totlen -= len;
 243		from += len;
 244	}
 245	return ret;
 246}
 247
 248/**
 249 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
 250 * @this: NAND chip object
 251 * @buf: temporary buffer
 252 * @td: descriptor for the bad block table
 253 * @chip: read the table for a specific chip, -1 read all chips; applies only if
 254 *        NAND_BBT_PERCHIP option is set
 255 *
 256 * Read the bad block table for all chips starting at a given page. We assume
 257 * that the bbt bits are in consecutive order.
 258 */
 259static int read_abs_bbt(struct nand_chip *this, uint8_t *buf,
 260			struct nand_bbt_descr *td, int chip)
 261{
 262	struct mtd_info *mtd = nand_to_mtd(this);
 263	u64 targetsize = nanddev_target_size(&this->base);
 264	int res = 0, i;
 265
 266	if (td->options & NAND_BBT_PERCHIP) {
 267		int offs = 0;
 268		for (i = 0; i < nanddev_ntargets(&this->base); i++) {
 269			if (chip == -1 || chip == i)
 270				res = read_bbt(this, buf, td->pages[i],
 271					targetsize >> this->bbt_erase_shift,
 272					td, offs);
 273			if (res)
 274				return res;
 275			offs += targetsize >> this->bbt_erase_shift;
 276		}
 277	} else {
 278		res = read_bbt(this, buf, td->pages[0],
 279				mtd->size >> this->bbt_erase_shift, td, 0);
 280		if (res)
 281			return res;
 282	}
 283	return 0;
 284}
 285
 286/* BBT marker is in the first page, no OOB */
 287static int scan_read_data(struct nand_chip *this, uint8_t *buf, loff_t offs,
 288			  struct nand_bbt_descr *td)
 289{
 290	struct mtd_info *mtd = nand_to_mtd(this);
 291	size_t retlen;
 292	size_t len;
 293
 294	len = td->len;
 295	if (td->options & NAND_BBT_VERSION)
 296		len++;
 297
 298	return mtd_read(mtd, offs, len, &retlen, buf);
 299}
 300
 301/**
 302 * scan_read_oob - [GENERIC] Scan data+OOB region to buffer
 303 * @this: NAND chip object
 304 * @buf: temporary buffer
 305 * @offs: offset at which to scan
 306 * @len: length of data region to read
 307 *
 308 * Scan read data from data+OOB. May traverse multiple pages, interleaving
 309 * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest"
 310 * ECC condition (error or bitflip). May quit on the first (non-ECC) error.
 311 */
 312static int scan_read_oob(struct nand_chip *this, uint8_t *buf, loff_t offs,
 313			 size_t len)
 314{
 315	struct mtd_info *mtd = nand_to_mtd(this);
 316	struct mtd_oob_ops ops = { };
 317	int res, ret = 0;
 318
 319	ops.mode = MTD_OPS_PLACE_OOB;
 320	ops.ooboffs = 0;
 321	ops.ooblen = mtd->oobsize;
 322
 323	while (len > 0) {
 324		ops.datbuf = buf;
 325		ops.len = min(len, (size_t)mtd->writesize);
 326		ops.oobbuf = buf + ops.len;
 327
 328		res = mtd_read_oob(mtd, offs, &ops);
 329		if (res) {
 330			if (!mtd_is_bitflip_or_eccerr(res))
 331				return res;
 332			else if (mtd_is_eccerr(res) || !ret)
 333				ret = res;
 334		}
 335
 336		buf += mtd->oobsize + mtd->writesize;
 337		len -= mtd->writesize;
 338		offs += mtd->writesize;
 339	}
 340	return ret;
 341}
 342
 343static int scan_read(struct nand_chip *this, uint8_t *buf, loff_t offs,
 344		     size_t len, struct nand_bbt_descr *td)
 345{
 346	if (td->options & NAND_BBT_NO_OOB)
 347		return scan_read_data(this, buf, offs, td);
 348	else
 349		return scan_read_oob(this, buf, offs, len);
 350}
 351
 352/* Scan write data with oob to flash */
 353static int scan_write_bbt(struct nand_chip *this, loff_t offs, size_t len,
 354			  uint8_t *buf, uint8_t *oob)
 355{
 356	struct mtd_info *mtd = nand_to_mtd(this);
 357	struct mtd_oob_ops ops = { };
 358
 359	ops.mode = MTD_OPS_PLACE_OOB;
 360	ops.ooboffs = 0;
 361	ops.ooblen = mtd->oobsize;
 362	ops.datbuf = buf;
 363	ops.oobbuf = oob;
 364	ops.len = len;
 365
 366	return mtd_write_oob(mtd, offs, &ops);
 367}
 368
 369static u32 bbt_get_ver_offs(struct nand_chip *this, struct nand_bbt_descr *td)
 370{
 371	struct mtd_info *mtd = nand_to_mtd(this);
 372	u32 ver_offs = td->veroffs;
 373
 374	if (!(td->options & NAND_BBT_NO_OOB))
 375		ver_offs += mtd->writesize;
 376	return ver_offs;
 377}
 378
 379/**
 380 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
 381 * @this: NAND chip object
 382 * @buf: temporary buffer
 383 * @td: descriptor for the bad block table
 384 * @md:	descriptor for the bad block table mirror
 385 *
 386 * Read the bad block table(s) for all chips starting at a given page. We
 387 * assume that the bbt bits are in consecutive order.
 388 */
 389static void read_abs_bbts(struct nand_chip *this, uint8_t *buf,
 390			  struct nand_bbt_descr *td, struct nand_bbt_descr *md)
 391{
 392	struct mtd_info *mtd = nand_to_mtd(this);
 393
 394	/* Read the primary version, if available */
 395	if (td->options & NAND_BBT_VERSION) {
 396		scan_read(this, buf, (loff_t)td->pages[0] << this->page_shift,
 397			  mtd->writesize, td);
 398		td->version[0] = buf[bbt_get_ver_offs(this, td)];
 399		pr_info("Bad block table at page %d, version 0x%02X\n",
 400			 td->pages[0], td->version[0]);
 401	}
 402
 403	/* Read the mirror version, if available */
 404	if (md && (md->options & NAND_BBT_VERSION)) {
 405		scan_read(this, buf, (loff_t)md->pages[0] << this->page_shift,
 406			  mtd->writesize, md);
 407		md->version[0] = buf[bbt_get_ver_offs(this, md)];
 408		pr_info("Bad block table at page %d, version 0x%02X\n",
 409			 md->pages[0], md->version[0]);
 410	}
 411}
 412
 413/* Scan a given block partially */
 414static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
 415			   loff_t offs, uint8_t *buf)
 416{
 417	struct mtd_info *mtd = nand_to_mtd(this);
 418
 419	struct mtd_oob_ops ops = { };
 420	int ret, page_offset;
 421
 422	ops.ooblen = mtd->oobsize;
 423	ops.oobbuf = buf;
 424	ops.ooboffs = 0;
 425	ops.datbuf = NULL;
 426	ops.mode = MTD_OPS_PLACE_OOB;
 427
 428	page_offset = nand_bbm_get_next_page(this, 0);
 429
 430	while (page_offset >= 0) {
 431		/*
 432		 * Read the full oob until read_oob is fixed to handle single
 433		 * byte reads for 16 bit buswidth.
 434		 */
 435		ret = mtd_read_oob(mtd, offs + (page_offset * mtd->writesize),
 436				   &ops);
 437		/* Ignore ECC errors when checking for BBM */
 438		if (ret && !mtd_is_bitflip_or_eccerr(ret))
 439			return ret;
 440
 441		if (check_short_pattern(buf, bd))
 442			return 1;
 443
 444		page_offset = nand_bbm_get_next_page(this, page_offset + 1);
 445	}
 446
 447	return 0;
 448}
 449
 450/* Check if a potential BBT block is marked as bad */
 451static int bbt_block_checkbad(struct nand_chip *this, struct nand_bbt_descr *td,
 452			      loff_t offs, uint8_t *buf)
 453{
 454	struct nand_bbt_descr *bd = this->badblock_pattern;
 455
 456	/*
 457	 * No need to check for a bad BBT block if the BBM area overlaps with
 458	 * the bad block table marker area in OOB since writing a BBM here
 459	 * invalidates the bad block table marker anyway.
 460	 */
 461	if (!(td->options & NAND_BBT_NO_OOB) &&
 462	    td->offs >= bd->offs && td->offs < bd->offs + bd->len)
 463		return 0;
 464
 465	/*
 466	 * There is no point in checking for a bad block marker if writing
 467	 * such marker is not supported
 468	 */
 469	if (this->bbt_options & NAND_BBT_NO_OOB_BBM ||
 470	    this->options & NAND_NO_BBM_QUIRK)
 471		return 0;
 472
 473	if (scan_block_fast(this, bd, offs, buf) > 0)
 474		return 1;
 475
 476	return 0;
 477}
 478
 479/**
 480 * create_bbt - [GENERIC] Create a bad block table by scanning the device
 481 * @this: NAND chip object
 482 * @buf: temporary buffer
 483 * @bd: descriptor for the good/bad block search pattern
 484 * @chip: create the table for a specific chip, -1 read all chips; applies only
 485 *        if NAND_BBT_PERCHIP option is set
 486 *
 487 * Create a bad block table by scanning the device for the given good/bad block
 488 * identify pattern.
 489 */
 490static int create_bbt(struct nand_chip *this, uint8_t *buf,
 491		      struct nand_bbt_descr *bd, int chip)
 492{
 493	u64 targetsize = nanddev_target_size(&this->base);
 494	struct mtd_info *mtd = nand_to_mtd(this);
 495	int i, numblocks, startblock;
 496	loff_t from;
 497
 498	pr_info("Scanning device for bad blocks\n");
 499
 500	if (chip == -1) {
 501		numblocks = mtd->size >> this->bbt_erase_shift;
 502		startblock = 0;
 503		from = 0;
 504	} else {
 505		if (chip >= nanddev_ntargets(&this->base)) {
 506			pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
 507			        chip + 1, nanddev_ntargets(&this->base));
 508			return -EINVAL;
 509		}
 510		numblocks = targetsize >> this->bbt_erase_shift;
 511		startblock = chip * numblocks;
 512		numblocks += startblock;
 513		from = (loff_t)startblock << this->bbt_erase_shift;
 514	}
 515
 516	for (i = startblock; i < numblocks; i++) {
 517		int ret;
 518
 519		BUG_ON(bd->options & NAND_BBT_NO_OOB);
 520
 521		ret = scan_block_fast(this, bd, from, buf);
 522		if (ret < 0)
 523			return ret;
 524
 525		if (ret) {
 526			bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
 527			pr_warn("Bad eraseblock %d at 0x%012llx\n",
 528				i, (unsigned long long)from);
 529			mtd->ecc_stats.badblocks++;
 530		}
 531
 532		from += (1 << this->bbt_erase_shift);
 533	}
 534	return 0;
 535}
 536
 537/**
 538 * search_bbt - [GENERIC] scan the device for a specific bad block table
 539 * @this: NAND chip object
 540 * @buf: temporary buffer
 541 * @td: descriptor for the bad block table
 542 *
 543 * Read the bad block table by searching for a given ident pattern. Search is
 544 * preformed either from the beginning up or from the end of the device
 545 * downwards. The search starts always at the start of a block. If the option
 546 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
 547 * the bad block information of this chip. This is necessary to provide support
 548 * for certain DOC devices.
 549 *
 550 * The bbt ident pattern resides in the oob area of the first page in a block.
 551 */
 552static int search_bbt(struct nand_chip *this, uint8_t *buf,
 553		      struct nand_bbt_descr *td)
 554{
 555	u64 targetsize = nanddev_target_size(&this->base);
 556	struct mtd_info *mtd = nand_to_mtd(this);
 557	int i, chips;
 558	int startblock, block, dir;
 559	int scanlen = mtd->writesize + mtd->oobsize;
 560	int bbtblocks;
 561	int blocktopage = this->bbt_erase_shift - this->page_shift;
 562
 563	/* Search direction top -> down? */
 564	if (td->options & NAND_BBT_LASTBLOCK) {
 565		startblock = (mtd->size >> this->bbt_erase_shift) - 1;
 566		dir = -1;
 567	} else {
 568		startblock = 0;
 569		dir = 1;
 570	}
 571
 572	/* Do we have a bbt per chip? */
 573	if (td->options & NAND_BBT_PERCHIP) {
 574		chips = nanddev_ntargets(&this->base);
 575		bbtblocks = targetsize >> this->bbt_erase_shift;
 576		startblock &= bbtblocks - 1;
 577	} else {
 578		chips = 1;
 579		bbtblocks = mtd->size >> this->bbt_erase_shift;
 580	}
 581
 582	for (i = 0; i < chips; i++) {
 583		/* Reset version information */
 584		td->version[i] = 0;
 585		td->pages[i] = -1;
 586		/* Scan the maximum number of blocks */
 587		for (block = 0; block < td->maxblocks; block++) {
 588
 589			int actblock = startblock + dir * block;
 590			loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
 591
 592			/* Check if block is marked bad */
 593			if (bbt_block_checkbad(this, td, offs, buf))
 594				continue;
 595
 596			/* Read first page */
 597			scan_read(this, buf, offs, mtd->writesize, td);
 598			if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
 599				td->pages[i] = actblock << blocktopage;
 600				if (td->options & NAND_BBT_VERSION) {
 601					offs = bbt_get_ver_offs(this, td);
 602					td->version[i] = buf[offs];
 603				}
 604				break;
 605			}
 606		}
 607		startblock += targetsize >> this->bbt_erase_shift;
 608	}
 609	/* Check, if we found a bbt for each requested chip */
 610	for (i = 0; i < chips; i++) {
 611		if (td->pages[i] == -1)
 612			pr_warn("Bad block table not found for chip %d\n", i);
 613		else
 614			pr_info("Bad block table found at page %d, version 0x%02X\n",
 615				td->pages[i], td->version[i]);
 616	}
 617	return 0;
 618}
 619
 620/**
 621 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
 622 * @this: NAND chip object
 623 * @buf: temporary buffer
 624 * @td: descriptor for the bad block table
 625 * @md: descriptor for the bad block table mirror
 626 *
 627 * Search and read the bad block table(s).
 628 */
 629static void search_read_bbts(struct nand_chip *this, uint8_t *buf,
 630			     struct nand_bbt_descr *td,
 631			     struct nand_bbt_descr *md)
 632{
 633	/* Search the primary table */
 634	search_bbt(this, buf, td);
 635
 636	/* Search the mirror table */
 637	if (md)
 638		search_bbt(this, buf, md);
 639}
 640
 641/**
 642 * get_bbt_block - Get the first valid eraseblock suitable to store a BBT
 643 * @this: the NAND device
 644 * @td: the BBT description
 645 * @md: the mirror BBT descriptor
 646 * @chip: the CHIP selector
 647 *
 648 * This functions returns a positive block number pointing a valid eraseblock
 649 * suitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC if
 650 * all blocks are already used of marked bad. If td->pages[chip] was already
 651 * pointing to a valid block we re-use it, otherwise we search for the next
 652 * valid one.
 653 */
 654static int get_bbt_block(struct nand_chip *this, struct nand_bbt_descr *td,
 655			 struct nand_bbt_descr *md, int chip)
 656{
 657	u64 targetsize = nanddev_target_size(&this->base);
 658	int startblock, dir, page, numblocks, i;
 659
 660	/*
 661	 * There was already a version of the table, reuse the page. This
 662	 * applies for absolute placement too, as we have the page number in
 663	 * td->pages.
 664	 */
 665	if (td->pages[chip] != -1)
 666		return td->pages[chip] >>
 667				(this->bbt_erase_shift - this->page_shift);
 668
 669	numblocks = (int)(targetsize >> this->bbt_erase_shift);
 670	if (!(td->options & NAND_BBT_PERCHIP))
 671		numblocks *= nanddev_ntargets(&this->base);
 672
 673	/*
 674	 * Automatic placement of the bad block table. Search direction
 675	 * top -> down?
 676	 */
 677	if (td->options & NAND_BBT_LASTBLOCK) {
 678		startblock = numblocks * (chip + 1) - 1;
 679		dir = -1;
 680	} else {
 681		startblock = chip * numblocks;
 682		dir = 1;
 683	}
 684
 685	for (i = 0; i < td->maxblocks; i++) {
 686		int block = startblock + dir * i;
 687
 688		/* Check, if the block is bad */
 689		switch (bbt_get_entry(this, block)) {
 690		case BBT_BLOCK_WORN:
 691		case BBT_BLOCK_FACTORY_BAD:
 692			continue;
 693		}
 694
 695		page = block << (this->bbt_erase_shift - this->page_shift);
 696
 697		/* Check, if the block is used by the mirror table */
 698		if (!md || md->pages[chip] != page)
 699			return block;
 700	}
 701
 702	return -ENOSPC;
 703}
 704
 705/**
 706 * mark_bbt_block_bad - Mark one of the block reserved for BBT bad
 707 * @this: the NAND device
 708 * @td: the BBT description
 709 * @chip: the CHIP selector
 710 * @block: the BBT block to mark
 711 *
 712 * Blocks reserved for BBT can become bad. This functions is an helper to mark
 713 * such blocks as bad. It takes care of updating the in-memory BBT, marking the
 714 * block as bad using a bad block marker and invalidating the associated
 715 * td->pages[] entry.
 716 */
 717static void mark_bbt_block_bad(struct nand_chip *this,
 718			       struct nand_bbt_descr *td,
 719			       int chip, int block)
 720{
 721	loff_t to;
 722	int res;
 723
 724	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
 725
 726	to = (loff_t)block << this->bbt_erase_shift;
 727	res = nand_markbad_bbm(this, to);
 728	if (res)
 729		pr_warn("nand_bbt: error %d while marking block %d bad\n",
 730			res, block);
 731
 732	td->pages[chip] = -1;
 733}
 734
 735/**
 736 * write_bbt - [GENERIC] (Re)write the bad block table
 737 * @this: NAND chip object
 738 * @buf: temporary buffer
 739 * @td: descriptor for the bad block table
 740 * @md: descriptor for the bad block table mirror
 741 * @chipsel: selector for a specific chip, -1 for all
 742 *
 743 * (Re)write the bad block table.
 744 */
 745static int write_bbt(struct nand_chip *this, uint8_t *buf,
 746		     struct nand_bbt_descr *td, struct nand_bbt_descr *md,
 747		     int chipsel)
 748{
 749	u64 targetsize = nanddev_target_size(&this->base);
 750	struct mtd_info *mtd = nand_to_mtd(this);
 751	struct erase_info einfo;
 752	int i, res, chip = 0;
 753	int bits, page, offs, numblocks, sft, sftmsk;
 754	int nrchips, pageoffs, ooboffs;
 755	uint8_t msk[4];
 756	uint8_t rcode = td->reserved_block_code;
 757	size_t retlen, len = 0;
 758	loff_t to;
 759	struct mtd_oob_ops ops = { };
 760
 761	ops.ooblen = mtd->oobsize;
 762	ops.ooboffs = 0;
 763	ops.datbuf = NULL;
 764	ops.mode = MTD_OPS_PLACE_OOB;
 765
 766	if (!rcode)
 767		rcode = 0xff;
 768	/* Write bad block table per chip rather than per device? */
 769	if (td->options & NAND_BBT_PERCHIP) {
 770		numblocks = (int)(targetsize >> this->bbt_erase_shift);
 771		/* Full device write or specific chip? */
 772		if (chipsel == -1) {
 773			nrchips = nanddev_ntargets(&this->base);
 774		} else {
 775			nrchips = chipsel + 1;
 776			chip = chipsel;
 777		}
 778	} else {
 779		numblocks = (int)(mtd->size >> this->bbt_erase_shift);
 780		nrchips = 1;
 781	}
 782
 783	/* Loop through the chips */
 784	while (chip < nrchips) {
 785		int block;
 786
 787		block = get_bbt_block(this, td, md, chip);
 788		if (block < 0) {
 789			pr_err("No space left to write bad block table\n");
 790			res = block;
 791			goto outerr;
 792		}
 793
 794		/*
 795		 * get_bbt_block() returns a block number, shift the value to
 796		 * get a page number.
 797		 */
 798		page = block << (this->bbt_erase_shift - this->page_shift);
 799
 800		/* Set up shift count and masks for the flash table */
 801		bits = td->options & NAND_BBT_NRBITS_MSK;
 802		msk[2] = ~rcode;
 803		switch (bits) {
 804		case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
 805			msk[3] = 0x01;
 806			break;
 807		case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
 808			msk[3] = 0x03;
 809			break;
 810		case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
 811			msk[3] = 0x0f;
 812			break;
 813		case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
 814			msk[3] = 0xff;
 815			break;
 816		default: return -EINVAL;
 817		}
 818
 819		to = ((loff_t)page) << this->page_shift;
 820
 821		/* Must we save the block contents? */
 822		if (td->options & NAND_BBT_SAVECONTENT) {
 823			/* Make it block aligned */
 824			to &= ~(((loff_t)1 << this->bbt_erase_shift) - 1);
 825			len = 1 << this->bbt_erase_shift;
 826			res = mtd_read(mtd, to, len, &retlen, buf);
 827			if (res < 0) {
 828				if (retlen != len) {
 829					pr_info("nand_bbt: error reading block for writing the bad block table\n");
 830					return res;
 831				}
 832				pr_warn("nand_bbt: ECC error while reading block for writing bad block table\n");
 833			}
 834			/* Read oob data */
 835			ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
 836			ops.oobbuf = &buf[len];
 837			res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
 838			if (res < 0 || ops.oobretlen != ops.ooblen)
 839				goto outerr;
 840
 841			/* Calc the byte offset in the buffer */
 842			pageoffs = page - (int)(to >> this->page_shift);
 843			offs = pageoffs << this->page_shift;
 844			/* Preset the bbt area with 0xff */
 845			memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
 846			ooboffs = len + (pageoffs * mtd->oobsize);
 847
 848		} else if (td->options & NAND_BBT_NO_OOB) {
 849			ooboffs = 0;
 850			offs = td->len;
 851			/* The version byte */
 852			if (td->options & NAND_BBT_VERSION)
 853				offs++;
 854			/* Calc length */
 855			len = (size_t)(numblocks >> sft);
 856			len += offs;
 857			/* Make it page aligned! */
 858			len = ALIGN(len, mtd->writesize);
 859			/* Preset the buffer with 0xff */
 860			memset(buf, 0xff, len);
 861			/* Pattern is located at the begin of first page */
 862			memcpy(buf, td->pattern, td->len);
 863		} else {
 864			/* Calc length */
 865			len = (size_t)(numblocks >> sft);
 866			/* Make it page aligned! */
 867			len = ALIGN(len, mtd->writesize);
 868			/* Preset the buffer with 0xff */
 869			memset(buf, 0xff, len +
 870			       (len >> this->page_shift)* mtd->oobsize);
 871			offs = 0;
 872			ooboffs = len;
 873			/* Pattern is located in oob area of first page */
 874			memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
 875		}
 876
 877		if (td->options & NAND_BBT_VERSION)
 878			buf[ooboffs + td->veroffs] = td->version[chip];
 879
 880		/* Walk through the memory table */
 881		for (i = 0; i < numblocks; i++) {
 882			uint8_t dat;
 883			int sftcnt = (i << (3 - sft)) & sftmsk;
 884			dat = bbt_get_entry(this, chip * numblocks + i);
 885			/* Do not store the reserved bbt blocks! */
 886			buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
 887		}
 888
 889		memset(&einfo, 0, sizeof(einfo));
 890		einfo.addr = to;
 891		einfo.len = 1 << this->bbt_erase_shift;
 892		res = nand_erase_nand(this, &einfo, 1);
 893		if (res < 0) {
 894			pr_warn("nand_bbt: error while erasing BBT block %d\n",
 895				res);
 896			mark_bbt_block_bad(this, td, chip, block);
 897			continue;
 898		}
 899
 900		res = scan_write_bbt(this, to, len, buf,
 901				     td->options & NAND_BBT_NO_OOB ?
 902				     NULL : &buf[len]);
 903		if (res < 0) {
 904			pr_warn("nand_bbt: error while writing BBT block %d\n",
 905				res);
 906			mark_bbt_block_bad(this, td, chip, block);
 907			continue;
 908		}
 909
 910		pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
 911			 (unsigned long long)to, td->version[chip]);
 912
 913		/* Mark it as used */
 914		td->pages[chip++] = page;
 915	}
 916	return 0;
 917
 918 outerr:
 919	pr_warn("nand_bbt: error while writing bad block table %d\n", res);
 920	return res;
 921}
 922
 923/**
 924 * nand_memory_bbt - [GENERIC] create a memory based bad block table
 925 * @this: NAND chip object
 926 * @bd: descriptor for the good/bad block search pattern
 927 *
 928 * The function creates a memory based bbt by scanning the device for
 929 * manufacturer / software marked good / bad blocks.
 930 */
 931static inline int nand_memory_bbt(struct nand_chip *this,
 932				  struct nand_bbt_descr *bd)
 933{
 934	u8 *pagebuf = nand_get_data_buf(this);
 935
 936	return create_bbt(this, pagebuf, bd, -1);
 937}
 938
 939/**
 940 * check_create - [GENERIC] create and write bbt(s) if necessary
 941 * @this: the NAND device
 942 * @buf: temporary buffer
 943 * @bd: descriptor for the good/bad block search pattern
 944 *
 945 * The function checks the results of the previous call to read_bbt and creates
 946 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
 947 * for the chip/device. Update is necessary if one of the tables is missing or
 948 * the version nr. of one table is less than the other.
 949 */
 950static int check_create(struct nand_chip *this, uint8_t *buf,
 951			struct nand_bbt_descr *bd)
 952{
 953	int i, chips, writeops, create, chipsel, res, res2;
 954	struct nand_bbt_descr *td = this->bbt_td;
 955	struct nand_bbt_descr *md = this->bbt_md;
 956	struct nand_bbt_descr *rd, *rd2;
 957
 958	/* Do we have a bbt per chip? */
 959	if (td->options & NAND_BBT_PERCHIP)
 960		chips = nanddev_ntargets(&this->base);
 961	else
 962		chips = 1;
 963
 964	for (i = 0; i < chips; i++) {
 965		writeops = 0;
 966		create = 0;
 967		rd = NULL;
 968		rd2 = NULL;
 969		res = res2 = 0;
 970		/* Per chip or per device? */
 971		chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
 972		/* Mirrored table available? */
 973		if (md) {
 974			if (td->pages[i] == -1 && md->pages[i] == -1) {
 975				create = 1;
 976				writeops = 0x03;
 977			} else if (td->pages[i] == -1) {
 978				rd = md;
 979				writeops = 0x01;
 980			} else if (md->pages[i] == -1) {
 981				rd = td;
 982				writeops = 0x02;
 983			} else if (td->version[i] == md->version[i]) {
 984				rd = td;
 985				if (!(td->options & NAND_BBT_VERSION))
 986					rd2 = md;
 987			} else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
 988				rd = td;
 989				writeops = 0x02;
 990			} else {
 991				rd = md;
 992				writeops = 0x01;
 993			}
 994		} else {
 995			if (td->pages[i] == -1) {
 996				create = 1;
 997				writeops = 0x01;
 998			} else {
 999				rd = td;
1000			}
1001		}
1002
1003		if (create) {
1004			/* Create the bad block table by scanning the device? */
1005			if (!(td->options & NAND_BBT_CREATE))
1006				continue;
1007
1008			/* Create the table in memory by scanning the chip(s) */
1009			if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
1010				create_bbt(this, buf, bd, chipsel);
1011
1012			td->version[i] = 1;
1013			if (md)
1014				md->version[i] = 1;
1015		}
1016
1017		/* Read back first? */
1018		if (rd) {
1019			res = read_abs_bbt(this, buf, rd, chipsel);
1020			if (mtd_is_eccerr(res)) {
1021				/* Mark table as invalid */
1022				rd->pages[i] = -1;
1023				rd->version[i] = 0;
1024				i--;
1025				continue;
1026			}
1027		}
1028		/* If they weren't versioned, read both */
1029		if (rd2) {
1030			res2 = read_abs_bbt(this, buf, rd2, chipsel);
1031			if (mtd_is_eccerr(res2)) {
1032				/* Mark table as invalid */
1033				rd2->pages[i] = -1;
1034				rd2->version[i] = 0;
1035				i--;
1036				continue;
1037			}
1038		}
1039
1040		/* Scrub the flash table(s)? */
1041		if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
1042			writeops = 0x03;
1043
1044		/* Update version numbers before writing */
1045		if (md) {
1046			td->version[i] = max(td->version[i], md->version[i]);
1047			md->version[i] = td->version[i];
1048		}
1049
1050		/* Write the bad block table to the device? */
1051		if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1052			res = write_bbt(this, buf, td, md, chipsel);
1053			if (res < 0)
1054				return res;
1055		}
1056
1057		/* Write the mirror bad block table to the device? */
1058		if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1059			res = write_bbt(this, buf, md, td, chipsel);
1060			if (res < 0)
1061				return res;
1062		}
1063	}
1064	return 0;
1065}
1066
1067/**
1068 * nand_update_bbt - update bad block table(s)
1069 * @this: the NAND device
1070 * @offs: the offset of the newly marked block
1071 *
1072 * The function updates the bad block table(s).
1073 */
1074static int nand_update_bbt(struct nand_chip *this, loff_t offs)
1075{
1076	struct mtd_info *mtd = nand_to_mtd(this);
1077	int len, res = 0;
1078	int chip, chipsel;
1079	uint8_t *buf;
1080	struct nand_bbt_descr *td = this->bbt_td;
1081	struct nand_bbt_descr *md = this->bbt_md;
1082
1083	if (!this->bbt || !td)
1084		return -EINVAL;
1085
1086	/* Allocate a temporary buffer for one eraseblock incl. oob */
1087	len = (1 << this->bbt_erase_shift);
1088	len += (len >> this->page_shift) * mtd->oobsize;
1089	buf = kmalloc(len, GFP_KERNEL);
1090	if (!buf)
1091		return -ENOMEM;
1092
1093	/* Do we have a bbt per chip? */
1094	if (td->options & NAND_BBT_PERCHIP) {
1095		chip = (int)(offs >> this->chip_shift);
1096		chipsel = chip;
1097	} else {
1098		chip = 0;
1099		chipsel = -1;
1100	}
1101
1102	td->version[chip]++;
1103	if (md)
1104		md->version[chip]++;
1105
1106	/* Write the bad block table to the device? */
1107	if (td->options & NAND_BBT_WRITE) {
1108		res = write_bbt(this, buf, td, md, chipsel);
1109		if (res < 0)
1110			goto out;
1111	}
1112	/* Write the mirror bad block table to the device? */
1113	if (md && (md->options & NAND_BBT_WRITE)) {
1114		res = write_bbt(this, buf, md, td, chipsel);
1115	}
1116
1117 out:
1118	kfree(buf);
1119	return res;
1120}
1121
1122/**
1123 * mark_bbt_region - [GENERIC] mark the bad block table regions
1124 * @this: the NAND device
1125 * @td: bad block table descriptor
1126 *
1127 * The bad block table regions are marked as "bad" to prevent accidental
1128 * erasures / writes. The regions are identified by the mark 0x02.
1129 */
1130static void mark_bbt_region(struct nand_chip *this, struct nand_bbt_descr *td)
1131{
1132	u64 targetsize = nanddev_target_size(&this->base);
1133	struct mtd_info *mtd = nand_to_mtd(this);
1134	int i, j, chips, block, nrblocks, update;
1135	uint8_t oldval;
1136
1137	/* Do we have a bbt per chip? */
1138	if (td->options & NAND_BBT_PERCHIP) {
1139		chips = nanddev_ntargets(&this->base);
1140		nrblocks = (int)(targetsize >> this->bbt_erase_shift);
1141	} else {
1142		chips = 1;
1143		nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1144	}
1145
1146	for (i = 0; i < chips; i++) {
1147		if ((td->options & NAND_BBT_ABSPAGE) ||
1148		    !(td->options & NAND_BBT_WRITE)) {
1149			if (td->pages[i] == -1)
1150				continue;
1151			block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1152			oldval = bbt_get_entry(this, block);
1153			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1154			if ((oldval != BBT_BLOCK_RESERVED) &&
1155					td->reserved_block_code)
1156				nand_update_bbt(this, (loff_t)block <<
1157						this->bbt_erase_shift);
1158			continue;
1159		}
1160		update = 0;
1161		if (td->options & NAND_BBT_LASTBLOCK)
1162			block = ((i + 1) * nrblocks) - td->maxblocks;
1163		else
1164			block = i * nrblocks;
1165		for (j = 0; j < td->maxblocks; j++) {
1166			oldval = bbt_get_entry(this, block);
1167			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1168			if (oldval != BBT_BLOCK_RESERVED)
1169				update = 1;
1170			block++;
1171		}
1172		/*
1173		 * If we want reserved blocks to be recorded to flash, and some
1174		 * new ones have been marked, then we need to update the stored
1175		 * bbts.  This should only happen once.
1176		 */
1177		if (update && td->reserved_block_code)
1178			nand_update_bbt(this, (loff_t)(block - 1) <<
1179					this->bbt_erase_shift);
1180	}
1181}
1182
1183/**
1184 * verify_bbt_descr - verify the bad block description
1185 * @this: the NAND device
1186 * @bd: the table to verify
1187 *
1188 * This functions performs a few sanity checks on the bad block description
1189 * table.
1190 */
1191static void verify_bbt_descr(struct nand_chip *this, struct nand_bbt_descr *bd)
1192{
1193	u64 targetsize = nanddev_target_size(&this->base);
1194	struct mtd_info *mtd = nand_to_mtd(this);
1195	u32 pattern_len;
1196	u32 bits;
1197	u32 table_size;
1198
1199	if (!bd)
1200		return;
1201
1202	pattern_len = bd->len;
1203	bits = bd->options & NAND_BBT_NRBITS_MSK;
1204
1205	BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1206			!(this->bbt_options & NAND_BBT_USE_FLASH));
1207	BUG_ON(!bits);
1208
1209	if (bd->options & NAND_BBT_VERSION)
1210		pattern_len++;
1211
1212	if (bd->options & NAND_BBT_NO_OOB) {
1213		BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1214		BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1215		BUG_ON(bd->offs);
1216		if (bd->options & NAND_BBT_VERSION)
1217			BUG_ON(bd->veroffs != bd->len);
1218		BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1219	}
1220
1221	if (bd->options & NAND_BBT_PERCHIP)
1222		table_size = targetsize >> this->bbt_erase_shift;
1223	else
1224		table_size = mtd->size >> this->bbt_erase_shift;
1225	table_size >>= 3;
1226	table_size *= bits;
1227	if (bd->options & NAND_BBT_NO_OOB)
1228		table_size += pattern_len;
1229	BUG_ON(table_size > (1 << this->bbt_erase_shift));
1230}
1231
1232/**
1233 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1234 * @this: the NAND device
1235 * @bd: descriptor for the good/bad block search pattern
1236 *
1237 * The function checks, if a bad block table(s) is/are already available. If
1238 * not it scans the device for manufacturer marked good / bad blocks and writes
1239 * the bad block table(s) to the selected place.
1240 *
1241 * The bad block table memory is allocated here. It must be freed by calling
1242 * the nand_free_bbt function.
1243 */
1244static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
1245{
1246	struct mtd_info *mtd = nand_to_mtd(this);
1247	int len, res;
1248	uint8_t *buf;
1249	struct nand_bbt_descr *td = this->bbt_td;
1250	struct nand_bbt_descr *md = this->bbt_md;
1251
1252	len = (mtd->size >> (this->bbt_erase_shift + 2)) ? : 1;
1253	/*
1254	 * Allocate memory (2bit per block) and clear the memory bad block
1255	 * table.
1256	 */
1257	this->bbt = kzalloc(len, GFP_KERNEL);
1258	if (!this->bbt)
1259		return -ENOMEM;
1260
1261	/*
1262	 * If no primary table descriptor is given, scan the device to build a
1263	 * memory based bad block table.
1264	 */
1265	if (!td) {
1266		if ((res = nand_memory_bbt(this, bd))) {
1267			pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1268			goto err_free_bbt;
1269		}
1270		return 0;
1271	}
1272	verify_bbt_descr(this, td);
1273	verify_bbt_descr(this, md);
1274
1275	/* Allocate a temporary buffer for one eraseblock incl. oob */
1276	len = (1 << this->bbt_erase_shift);
1277	len += (len >> this->page_shift) * mtd->oobsize;
1278	buf = vmalloc(len);
1279	if (!buf) {
1280		res = -ENOMEM;
1281		goto err_free_bbt;
1282	}
1283
1284	/* Is the bbt at a given page? */
1285	if (td->options & NAND_BBT_ABSPAGE) {
1286		read_abs_bbts(this, buf, td, md);
1287	} else {
1288		/* Search the bad block table using a pattern in oob */
1289		search_read_bbts(this, buf, td, md);
1290	}
1291
1292	res = check_create(this, buf, bd);
1293	if (res)
1294		goto err_free_buf;
1295
1296	/* Prevent the bbt regions from erasing / writing */
1297	mark_bbt_region(this, td);
1298	if (md)
1299		mark_bbt_region(this, md);
1300
1301	vfree(buf);
1302	return 0;
1303
1304err_free_buf:
1305	vfree(buf);
1306err_free_bbt:
1307	kfree(this->bbt);
1308	this->bbt = NULL;
1309	return res;
1310}
1311
1312/*
1313 * Define some generic bad / good block scan pattern which are used
1314 * while scanning a device for factory marked good / bad blocks.
1315 */
1316static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1317
1318/* Generic flash bbt descriptors */
1319static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1320static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1321
1322static struct nand_bbt_descr bbt_main_descr = {
1323	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1324		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1325	.offs =	8,
1326	.len = 4,
1327	.veroffs = 12,
1328	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1329	.pattern = bbt_pattern
1330};
1331
1332static struct nand_bbt_descr bbt_mirror_descr = {
1333	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1334		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1335	.offs =	8,
1336	.len = 4,
1337	.veroffs = 12,
1338	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1339	.pattern = mirror_pattern
1340};
1341
1342static struct nand_bbt_descr bbt_main_no_oob_descr = {
1343	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1344		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1345		| NAND_BBT_NO_OOB,
1346	.len = 4,
1347	.veroffs = 4,
1348	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1349	.pattern = bbt_pattern
1350};
1351
1352static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
1353	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1354		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1355		| NAND_BBT_NO_OOB,
1356	.len = 4,
1357	.veroffs = 4,
1358	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1359	.pattern = mirror_pattern
1360};
1361
1362#define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1363/**
1364 * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1365 * @this: NAND chip to create descriptor for
1366 *
1367 * This function allocates and initializes a nand_bbt_descr for BBM detection
1368 * based on the properties of @this. The new descriptor is stored in
1369 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1370 * passed to this function.
1371 */
1372static int nand_create_badblock_pattern(struct nand_chip *this)
1373{
1374	struct nand_bbt_descr *bd;
1375	if (this->badblock_pattern) {
1376		pr_warn("Bad block pattern already allocated; not replacing\n");
1377		return -EINVAL;
1378	}
1379	bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1380	if (!bd)
1381		return -ENOMEM;
1382	bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1383	bd->offs = this->badblockpos;
1384	bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1385	bd->pattern = scan_ff_pattern;
1386	bd->options |= NAND_BBT_DYNAMICSTRUCT;
1387	this->badblock_pattern = bd;
1388	return 0;
1389}
1390
1391/**
1392 * nand_create_bbt - [NAND Interface] Select a default bad block table for the device
1393 * @this: NAND chip object
1394 *
1395 * This function selects the default bad block table support for the device and
1396 * calls the nand_scan_bbt function.
1397 */
1398int nand_create_bbt(struct nand_chip *this)
1399{
1400	int ret;
1401
1402	/* Is a flash based bad block table requested? */
1403	if (this->bbt_options & NAND_BBT_USE_FLASH) {
1404		/* Use the default pattern descriptors */
1405		if (!this->bbt_td) {
1406			if (this->bbt_options & NAND_BBT_NO_OOB) {
1407				this->bbt_td = &bbt_main_no_oob_descr;
1408				this->bbt_md = &bbt_mirror_no_oob_descr;
1409			} else {
1410				this->bbt_td = &bbt_main_descr;
1411				this->bbt_md = &bbt_mirror_descr;
1412			}
1413		}
1414	} else {
1415		this->bbt_td = NULL;
1416		this->bbt_md = NULL;
1417	}
1418
1419	if (!this->badblock_pattern) {
1420		ret = nand_create_badblock_pattern(this);
1421		if (ret)
1422			return ret;
1423	}
1424
1425	return nand_scan_bbt(this, this->badblock_pattern);
1426}
1427EXPORT_SYMBOL(nand_create_bbt);
1428
1429/**
1430 * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
1431 * @this: NAND chip object
1432 * @offs: offset in the device
1433 */
1434int nand_isreserved_bbt(struct nand_chip *this, loff_t offs)
1435{
1436	int block;
1437
1438	block = (int)(offs >> this->bbt_erase_shift);
1439	return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;
1440}
1441
1442/**
1443 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1444 * @this: NAND chip object
1445 * @offs: offset in the device
1446 * @allowbbt: allow access to bad block table region
1447 */
1448int nand_isbad_bbt(struct nand_chip *this, loff_t offs, int allowbbt)
1449{
1450	int block, res;
1451
1452	block = (int)(offs >> this->bbt_erase_shift);
1453	res = bbt_get_entry(this, block);
1454
1455	pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1456		 (unsigned int)offs, block, res);
1457
1458	if (mtd_check_expert_analysis_mode())
1459		return 0;
1460
1461	switch (res) {
1462	case BBT_BLOCK_GOOD:
1463		return 0;
1464	case BBT_BLOCK_WORN:
1465		return 1;
1466	case BBT_BLOCK_RESERVED:
1467		return allowbbt ? 0 : 1;
1468	}
1469	return 1;
1470}
1471
1472/**
1473 * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1474 * @this: NAND chip object
1475 * @offs: offset of the bad block
1476 */
1477int nand_markbad_bbt(struct nand_chip *this, loff_t offs)
1478{
1479	int block, ret = 0;
1480
1481	block = (int)(offs >> this->bbt_erase_shift);
1482
1483	/* Mark bad block in memory */
1484	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
1485
1486	/* Update flash-based bad block table */
1487	if (this->bbt_options & NAND_BBT_USE_FLASH)
1488		ret = nand_update_bbt(this, offs);
1489
1490	return ret;
1491}