2 * drivers/mtd/nand_bbt.c
5 * Bad block table support for the NAND driver
7 * Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
15 * When nand_scan_bbt is called, then it tries to find the bad block table
16 * depending on the options in the BBT descriptor(s). If no flash based BBT
17 * (NAND_BBT_USE_FLASH) is specified then the device is scanned for factory
18 * marked good / bad blocks. This information is used to create a memory BBT.
19 * Once a new bad block is discovered then the "factory" information is updated
21 * If a flash based BBT is specified then the function first tries to find the
22 * BBT on flash. If a BBT is found then the contents are read and the memory
23 * based BBT is created. If a mirrored BBT is selected then the mirror is
24 * searched too and the versions are compared. If the mirror has a greater
25 * version number, then the mirror BBT is used to build the memory based BBT.
26 * If the tables are not versioned, then we "or" the bad block information.
27 * If one of the BBTs is out of date or does not exist it is (re)created.
28 * If no BBT exists at all then the device is scanned for factory marked
29 * good / bad blocks and the bad block tables are created.
31 * For manufacturer created BBTs like the one found on M-SYS DOC devices
32 * the BBT is searched and read but never created
34 * The auto generated bad block table is located in the last good blocks
35 * of the device. The table is mirrored, so it can be updated eventually.
36 * The table is marked in the OOB area with an ident pattern and a version
37 * number which indicates which of both tables is more up to date. If the NAND
38 * controller needs the complete OOB area for the ECC information then the
39 * option NAND_BBT_NO_OOB should be used (along with NAND_BBT_USE_FLASH, of
40 * course): it moves the ident pattern and the version byte into the data area
41 * and the OOB area will remain untouched.
43 * The table uses 2 bits per block
45 * 00b: block is factory marked bad
46 * 01b, 10b: block is marked bad due to wear
48 * The memory bad block table uses the following scheme:
50 * 01b: block is marked bad due to wear
51 * 10b: block is reserved (to protect the bbt area)
52 * 11b: block is factory marked bad
54 * Multichip devices like DOC store the bad block info per floor.
56 * Following assumptions are made:
57 * - bbts start at a page boundary, if autolocated on a block boundary
58 * - the space necessary for a bbt in FLASH does not exceed a block boundary
62 #include <linux/slab.h>
63 #include <linux/types.h>
64 #include <linux/mtd/mtd.h>
65 #include <linux/mtd/nand.h>
66 #include <linux/mtd/nand_ecc.h>
67 #include <linux/bitops.h>
68 #include <linux/delay.h>
69 #include <linux/vmalloc.h>
70 #include <linux/export.h>
72 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
74 if (memcmp(buf, td->pattern, td->len))
80 * check_pattern - [GENERIC] check if a pattern is in the buffer
81 * @buf: the buffer to search
82 * @len: the length of buffer to search
83 * @paglen: the pagelength
84 * @td: search pattern descriptor
86 * Check for a pattern at the given place. Used to search bad block tables and
87 * good / bad block identifiers. If the SCAN_EMPTY option is set then check, if
88 * all bytes except the pattern area contain 0xff.
90 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
95 if (td->options & NAND_BBT_NO_OOB)
96 return check_pattern_no_oob(buf, td);
98 end = paglen + td->offs;
99 if (td->options & NAND_BBT_SCANEMPTY) {
100 for (i = 0; i < end; i++) {
107 /* Compare the pattern */
108 if (memcmp(p, td->pattern, td->len))
111 if (td->options & NAND_BBT_SCANEMPTY) {
114 for (i = end; i < len; i++) {
123 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
124 * @buf: the buffer to search
125 * @td: search pattern descriptor
127 * Check for a pattern at the given place. Used to search bad block tables and
128 * good / bad block identifiers. Same as check_pattern, but no optional empty
131 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
136 /* Compare the pattern */
137 for (i = 0; i < td->len; i++) {
138 if (p[td->offs + i] != td->pattern[i])
145 * add_marker_len - compute the length of the marker in data area
146 * @td: BBT descriptor used for computation
148 * The length will be 0 if the marker is located in OOB area.
150 static u32 add_marker_len(struct nand_bbt_descr *td)
154 if (!(td->options & NAND_BBT_NO_OOB))
158 if (td->options & NAND_BBT_VERSION)
164 * read_bbt - [GENERIC] Read the bad block table starting from page
165 * @mtd: MTD device structure
166 * @buf: temporary buffer
167 * @page: the starting page
168 * @num: the number of bbt descriptors to read
169 * @td: the bbt describtion table
170 * @offs: offset in the memory table
172 * Read the bad block table starting from page.
174 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
175 struct nand_bbt_descr *td, int offs)
177 int res, ret = 0, i, j, act = 0;
178 struct nand_chip *this = mtd->priv;
179 size_t retlen, len, totlen;
181 int bits = td->options & NAND_BBT_NRBITS_MSK;
182 uint8_t msk = (uint8_t)((1 << bits) - 1);
184 int reserved_block_code = td->reserved_block_code;
186 totlen = (num * bits) >> 3;
187 marker_len = add_marker_len(td);
188 from = ((loff_t)page) << this->page_shift;
191 len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
194 * In case the BBT marker is not in the OOB area it
195 * will be just in the first page.
201 res = mtd_read(mtd, from, len, &retlen, buf);
203 if (mtd_is_eccerr(res)) {
204 pr_info("nand_bbt: ECC error in BBT at "
205 "0x%012llx\n", from & ~mtd->writesize);
207 } else if (mtd_is_bitflip(res)) {
208 pr_info("nand_bbt: corrected error in BBT at "
209 "0x%012llx\n", from & ~mtd->writesize);
212 pr_info("nand_bbt: error reading BBT\n");
218 for (i = 0; i < len; i++) {
219 uint8_t dat = buf[i];
220 for (j = 0; j < 8; j += bits, act += 2) {
221 uint8_t tmp = (dat >> j) & msk;
224 if (reserved_block_code && (tmp == reserved_block_code)) {
225 pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
226 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
227 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
228 mtd->ecc_stats.bbtblocks++;
232 * Leave it for now, if it's matured we can
233 * move this message to pr_debug.
235 pr_info("nand_read_bbt: bad block at 0x%012llx\n",
236 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
237 /* Factory marked bad or worn out? */
239 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
241 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
242 mtd->ecc_stats.badblocks++;
252 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
253 * @mtd: MTD device structure
254 * @buf: temporary buffer
255 * @td: descriptor for the bad block table
256 * @chip: read the table for a specific chip, -1 read all chips; applies only if
257 * NAND_BBT_PERCHIP option is set
259 * Read the bad block table for all chips starting at a given page. We assume
260 * that the bbt bits are in consecutive order.
262 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
264 struct nand_chip *this = mtd->priv;
267 if (td->options & NAND_BBT_PERCHIP) {
269 for (i = 0; i < this->numchips; i++) {
270 if (chip == -1 || chip == i)
271 res = read_bbt(mtd, buf, td->pages[i],
272 this->chipsize >> this->bbt_erase_shift,
276 offs += this->chipsize >> (this->bbt_erase_shift + 2);
279 res = read_bbt(mtd, buf, td->pages[0],
280 mtd->size >> this->bbt_erase_shift, td, 0);
287 /* BBT marker is in the first page, no OOB */
288 static int scan_read_raw_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
289 struct nand_bbt_descr *td)
295 if (td->options & NAND_BBT_VERSION)
298 return mtd_read(mtd, offs, len, &retlen, buf);
301 /* Scan read raw data from flash */
302 static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
305 struct mtd_oob_ops ops;
308 ops.mode = MTD_OPS_RAW;
310 ops.ooblen = mtd->oobsize;
314 ops.len = min(len, (size_t)mtd->writesize);
315 ops.oobbuf = buf + ops.len;
317 res = mtd_read_oob(mtd, offs, &ops);
322 buf += mtd->oobsize + mtd->writesize;
323 len -= mtd->writesize;
324 offs += mtd->writesize;
329 static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
330 size_t len, struct nand_bbt_descr *td)
332 if (td->options & NAND_BBT_NO_OOB)
333 return scan_read_raw_data(mtd, buf, offs, td);
335 return scan_read_raw_oob(mtd, buf, offs, len);
338 /* Scan write data with oob to flash */
339 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
340 uint8_t *buf, uint8_t *oob)
342 struct mtd_oob_ops ops;
344 ops.mode = MTD_OPS_PLACE_OOB;
346 ops.ooblen = mtd->oobsize;
351 return mtd_write_oob(mtd, offs, &ops);
354 static u32 bbt_get_ver_offs(struct mtd_info *mtd, struct nand_bbt_descr *td)
356 u32 ver_offs = td->veroffs;
358 if (!(td->options & NAND_BBT_NO_OOB))
359 ver_offs += mtd->writesize;
364 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
365 * @mtd: MTD device structure
366 * @buf: temporary buffer
367 * @td: descriptor for the bad block table
368 * @md: descriptor for the bad block table mirror
370 * Read the bad block table(s) for all chips starting at a given page. We
371 * assume that the bbt bits are in consecutive order.
373 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
374 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
376 struct nand_chip *this = mtd->priv;
378 /* Read the primary version, if available */
379 if (td->options & NAND_BBT_VERSION) {
380 scan_read_raw(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
382 td->version[0] = buf[bbt_get_ver_offs(mtd, td)];
383 pr_info("Bad block table at page %d, version 0x%02X\n",
384 td->pages[0], td->version[0]);
387 /* Read the mirror version, if available */
388 if (md && (md->options & NAND_BBT_VERSION)) {
389 scan_read_raw(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
391 md->version[0] = buf[bbt_get_ver_offs(mtd, md)];
392 pr_info("Bad block table at page %d, version 0x%02X\n",
393 md->pages[0], md->version[0]);
398 /* Scan a given block full */
399 static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
400 loff_t offs, uint8_t *buf, size_t readlen,
401 int scanlen, int len)
405 ret = scan_read_raw_oob(mtd, buf, offs, readlen);
406 /* Ignore ECC errors when checking for BBM */
407 if (ret && !mtd_is_bitflip_or_eccerr(ret))
410 for (j = 0; j < len; j++, buf += scanlen) {
411 if (check_pattern(buf, scanlen, mtd->writesize, bd))
417 /* Scan a given block partially */
418 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
419 loff_t offs, uint8_t *buf, int len)
421 struct mtd_oob_ops ops;
424 ops.ooblen = mtd->oobsize;
428 ops.mode = MTD_OPS_PLACE_OOB;
430 for (j = 0; j < len; j++) {
432 * Read the full oob until read_oob is fixed to handle single
433 * byte reads for 16 bit buswidth.
435 ret = mtd_read_oob(mtd, offs, &ops);
436 /* Ignore ECC errors when checking for BBM */
437 if (ret && !mtd_is_bitflip_or_eccerr(ret))
440 if (check_short_pattern(buf, bd))
443 offs += mtd->writesize;
449 * create_bbt - [GENERIC] Create a bad block table by scanning the device
450 * @mtd: MTD device structure
451 * @buf: temporary buffer
452 * @bd: descriptor for the good/bad block search pattern
453 * @chip: create the table for a specific chip, -1 read all chips; applies only
454 * if NAND_BBT_PERCHIP option is set
456 * Create a bad block table by scanning the device for the given good/bad block
459 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
460 struct nand_bbt_descr *bd, int chip)
462 struct nand_chip *this = mtd->priv;
463 int i, numblocks, len, scanlen;
468 pr_info("Scanning device for bad blocks\n");
470 if (bd->options & NAND_BBT_SCANALLPAGES)
471 len = 1 << (this->bbt_erase_shift - this->page_shift);
472 else if (bd->options & NAND_BBT_SCAN2NDPAGE)
477 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
478 /* We need only read few bytes from the OOB area */
482 /* Full page content should be read */
483 scanlen = mtd->writesize + mtd->oobsize;
484 readlen = len * mtd->writesize;
489 * Note that numblocks is 2 * (real numblocks) here, see i+=2
490 * below as it makes shifting and masking less painful
492 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
496 if (chip >= this->numchips) {
497 pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
498 chip + 1, this->numchips);
501 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
502 startblock = chip * numblocks;
503 numblocks += startblock;
504 from = (loff_t)startblock << (this->bbt_erase_shift - 1);
507 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
508 from += mtd->erasesize - (mtd->writesize * len);
510 for (i = startblock; i < numblocks;) {
513 BUG_ON(bd->options & NAND_BBT_NO_OOB);
515 if (bd->options & NAND_BBT_SCANALLPAGES)
516 ret = scan_block_full(mtd, bd, from, buf, readlen,
519 ret = scan_block_fast(mtd, bd, from, buf, len);
525 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
526 pr_warn("Bad eraseblock %d at 0x%012llx\n",
527 i >> 1, (unsigned long long)from);
528 mtd->ecc_stats.badblocks++;
532 from += (1 << this->bbt_erase_shift);
538 * search_bbt - [GENERIC] scan the device for a specific bad block table
539 * @mtd: MTD device structure
540 * @buf: temporary buffer
541 * @td: descriptor for the bad block table
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.
550 * The bbt ident pattern resides in the oob area of the first page in a block.
552 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
554 struct nand_chip *this = mtd->priv;
556 int bits, startblock, block, dir;
557 int scanlen = mtd->writesize + mtd->oobsize;
559 int blocktopage = this->bbt_erase_shift - this->page_shift;
561 /* Search direction top -> down? */
562 if (td->options & NAND_BBT_LASTBLOCK) {
563 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
570 /* Do we have a bbt per chip? */
571 if (td->options & NAND_BBT_PERCHIP) {
572 chips = this->numchips;
573 bbtblocks = this->chipsize >> this->bbt_erase_shift;
574 startblock &= bbtblocks - 1;
577 bbtblocks = mtd->size >> this->bbt_erase_shift;
580 /* Number of bits for each erase block in the bbt */
581 bits = td->options & NAND_BBT_NRBITS_MSK;
583 for (i = 0; i < chips; i++) {
584 /* Reset version information */
587 /* Scan the maximum number of blocks */
588 for (block = 0; block < td->maxblocks; block++) {
590 int actblock = startblock + dir * block;
591 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
593 /* Read first page */
594 scan_read_raw(mtd, buf, offs, mtd->writesize, td);
595 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
596 td->pages[i] = actblock << blocktopage;
597 if (td->options & NAND_BBT_VERSION) {
598 offs = bbt_get_ver_offs(mtd, td);
599 td->version[i] = buf[offs];
604 startblock += this->chipsize >> this->bbt_erase_shift;
606 /* Check, if we found a bbt for each requested chip */
607 for (i = 0; i < chips; i++) {
608 if (td->pages[i] == -1)
609 pr_warn("Bad block table not found for chip %d\n", i);
611 pr_info("Bad block table found at page %d, version "
612 "0x%02X\n", td->pages[i], td->version[i]);
618 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
619 * @mtd: MTD device structure
620 * @buf: temporary buffer
621 * @td: descriptor for the bad block table
622 * @md: descriptor for the bad block table mirror
624 * Search and read the bad block table(s).
626 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
628 /* Search the primary table */
629 search_bbt(mtd, buf, td);
631 /* Search the mirror table */
633 search_bbt(mtd, buf, md);
635 /* Force result check */
640 * write_bbt - [GENERIC] (Re)write the bad block table
641 * @mtd: MTD device structure
642 * @buf: temporary buffer
643 * @td: descriptor for the bad block table
644 * @md: descriptor for the bad block table mirror
645 * @chipsel: selector for a specific chip, -1 for all
647 * (Re)write the bad block table.
649 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
650 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
653 struct nand_chip *this = mtd->priv;
654 struct erase_info einfo;
655 int i, j, res, chip = 0;
656 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
657 int nrchips, bbtoffs, pageoffs, ooboffs;
659 uint8_t rcode = td->reserved_block_code;
660 size_t retlen, len = 0;
662 struct mtd_oob_ops ops;
664 ops.ooblen = mtd->oobsize;
667 ops.mode = MTD_OPS_PLACE_OOB;
671 /* Write bad block table per chip rather than per device? */
672 if (td->options & NAND_BBT_PERCHIP) {
673 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
674 /* Full device write or specific chip? */
676 nrchips = this->numchips;
678 nrchips = chipsel + 1;
682 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
686 /* Loop through the chips */
687 for (; chip < nrchips; chip++) {
689 * There was already a version of the table, reuse the page
690 * This applies for absolute placement too, as we have the
691 * page nr. in td->pages.
693 if (td->pages[chip] != -1) {
694 page = td->pages[chip];
699 * Automatic placement of the bad block table. Search direction
702 if (td->options & NAND_BBT_LASTBLOCK) {
703 startblock = numblocks * (chip + 1) - 1;
706 startblock = chip * numblocks;
710 for (i = 0; i < td->maxblocks; i++) {
711 int block = startblock + dir * i;
712 /* Check, if the block is bad */
713 switch ((this->bbt[block >> 2] >>
714 (2 * (block & 0x03))) & 0x03) {
720 (this->bbt_erase_shift - this->page_shift);
721 /* Check, if the block is used by the mirror table */
722 if (!md || md->pages[chip] != page)
725 pr_err("No space left to write bad block table\n");
729 /* Set up shift count and masks for the flash table */
730 bits = td->options & NAND_BBT_NRBITS_MSK;
733 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
736 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
739 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
742 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
745 default: return -EINVAL;
748 bbtoffs = chip * (numblocks >> 2);
750 to = ((loff_t)page) << this->page_shift;
752 /* Must we save the block contents? */
753 if (td->options & NAND_BBT_SAVECONTENT) {
754 /* Make it block aligned */
755 to &= ~((loff_t)((1 << this->bbt_erase_shift) - 1));
756 len = 1 << this->bbt_erase_shift;
757 res = mtd_read(mtd, to, len, &retlen, buf);
760 pr_info("nand_bbt: error reading block "
761 "for writing the bad block table\n");
764 pr_warn("nand_bbt: ECC error while reading "
765 "block for writing bad block table\n");
768 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
769 ops.oobbuf = &buf[len];
770 res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
771 if (res < 0 || ops.oobretlen != ops.ooblen)
774 /* Calc the byte offset in the buffer */
775 pageoffs = page - (int)(to >> this->page_shift);
776 offs = pageoffs << this->page_shift;
777 /* Preset the bbt area with 0xff */
778 memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
779 ooboffs = len + (pageoffs * mtd->oobsize);
781 } else if (td->options & NAND_BBT_NO_OOB) {
784 /* The version byte */
785 if (td->options & NAND_BBT_VERSION)
788 len = (size_t)(numblocks >> sft);
790 /* Make it page aligned! */
791 len = ALIGN(len, mtd->writesize);
792 /* Preset the buffer with 0xff */
793 memset(buf, 0xff, len);
794 /* Pattern is located at the begin of first page */
795 memcpy(buf, td->pattern, td->len);
798 len = (size_t)(numblocks >> sft);
799 /* Make it page aligned! */
800 len = ALIGN(len, mtd->writesize);
801 /* Preset the buffer with 0xff */
802 memset(buf, 0xff, len +
803 (len >> this->page_shift)* mtd->oobsize);
806 /* Pattern is located in oob area of first page */
807 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
810 if (td->options & NAND_BBT_VERSION)
811 buf[ooboffs + td->veroffs] = td->version[chip];
813 /* Walk through the memory table */
814 for (i = 0; i < numblocks;) {
816 dat = this->bbt[bbtoffs + (i >> 2)];
817 for (j = 0; j < 4; j++, i++) {
818 int sftcnt = (i << (3 - sft)) & sftmsk;
819 /* Do not store the reserved bbt blocks! */
820 buf[offs + (i >> sft)] &=
821 ~(msk[dat & 0x03] << sftcnt);
826 memset(&einfo, 0, sizeof(einfo));
829 einfo.len = 1 << this->bbt_erase_shift;
830 res = nand_erase_nand(mtd, &einfo, 1);
834 res = scan_write_bbt(mtd, to, len, buf,
835 td->options & NAND_BBT_NO_OOB ? NULL :
840 pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
841 (unsigned long long)to, td->version[chip]);
843 /* Mark it as used */
844 td->pages[chip] = page;
849 pr_warn("nand_bbt: error while writing bad block table %d\n", res);
854 * nand_memory_bbt - [GENERIC] create a memory based bad block table
855 * @mtd: MTD device structure
856 * @bd: descriptor for the good/bad block search pattern
858 * The function creates a memory based bbt by scanning the device for
859 * manufacturer / software marked good / bad blocks.
861 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
863 struct nand_chip *this = mtd->priv;
865 bd->options &= ~NAND_BBT_SCANEMPTY;
866 return create_bbt(mtd, this->buffers->databuf, bd, -1);
870 * check_create - [GENERIC] create and write bbt(s) if necessary
871 * @mtd: MTD device structure
872 * @buf: temporary buffer
873 * @bd: descriptor for the good/bad block search pattern
875 * The function checks the results of the previous call to read_bbt and creates
876 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
877 * for the chip/device. Update is necessary if one of the tables is missing or
878 * the version nr. of one table is less than the other.
880 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
882 int i, chips, writeops, create, chipsel, res, res2;
883 struct nand_chip *this = mtd->priv;
884 struct nand_bbt_descr *td = this->bbt_td;
885 struct nand_bbt_descr *md = this->bbt_md;
886 struct nand_bbt_descr *rd, *rd2;
888 /* Do we have a bbt per chip? */
889 if (td->options & NAND_BBT_PERCHIP)
890 chips = this->numchips;
894 for (i = 0; i < chips; i++) {
900 /* Per chip or per device? */
901 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
902 /* Mirrored table available? */
904 if (td->pages[i] == -1 && md->pages[i] == -1) {
907 } else if (td->pages[i] == -1) {
910 } else if (md->pages[i] == -1) {
913 } else if (td->version[i] == md->version[i]) {
915 if (!(td->options & NAND_BBT_VERSION))
917 } else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
925 if (td->pages[i] == -1) {
934 /* Create the bad block table by scanning the device? */
935 if (!(td->options & NAND_BBT_CREATE))
938 /* Create the table in memory by scanning the chip(s) */
939 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
940 create_bbt(mtd, buf, bd, chipsel);
947 /* Read back first? */
949 res = read_abs_bbt(mtd, buf, rd, chipsel);
950 if (mtd_is_eccerr(res)) {
951 /* Mark table as invalid */
958 /* If they weren't versioned, read both */
960 res2 = read_abs_bbt(mtd, buf, rd2, chipsel);
961 if (mtd_is_eccerr(res2)) {
962 /* Mark table as invalid */
970 /* Scrub the flash table(s)? */
971 if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
974 /* Update version numbers before writing */
976 td->version[i] = max(td->version[i], md->version[i]);
977 md->version[i] = td->version[i];
980 /* Write the bad block table to the device? */
981 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
982 res = write_bbt(mtd, buf, td, md, chipsel);
987 /* Write the mirror bad block table to the device? */
988 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
989 res = write_bbt(mtd, buf, md, td, chipsel);
998 * mark_bbt_regions - [GENERIC] mark the bad block table regions
999 * @mtd: MTD device structure
1000 * @td: bad block table descriptor
1002 * The bad block table regions are marked as "bad" to prevent accidental
1003 * erasures / writes. The regions are identified by the mark 0x02.
1005 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
1007 struct nand_chip *this = mtd->priv;
1008 int i, j, chips, block, nrblocks, update;
1009 uint8_t oldval, newval;
1011 /* Do we have a bbt per chip? */
1012 if (td->options & NAND_BBT_PERCHIP) {
1013 chips = this->numchips;
1014 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
1017 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1020 for (i = 0; i < chips; i++) {
1021 if ((td->options & NAND_BBT_ABSPAGE) ||
1022 !(td->options & NAND_BBT_WRITE)) {
1023 if (td->pages[i] == -1)
1025 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1027 oldval = this->bbt[(block >> 3)];
1028 newval = oldval | (0x2 << (block & 0x06));
1029 this->bbt[(block >> 3)] = newval;
1030 if ((oldval != newval) && td->reserved_block_code)
1031 nand_update_bbt(mtd, (loff_t)block << (this->bbt_erase_shift - 1));
1035 if (td->options & NAND_BBT_LASTBLOCK)
1036 block = ((i + 1) * nrblocks) - td->maxblocks;
1038 block = i * nrblocks;
1040 for (j = 0; j < td->maxblocks; j++) {
1041 oldval = this->bbt[(block >> 3)];
1042 newval = oldval | (0x2 << (block & 0x06));
1043 this->bbt[(block >> 3)] = newval;
1044 if (oldval != newval)
1049 * If we want reserved blocks to be recorded to flash, and some
1050 * new ones have been marked, then we need to update the stored
1051 * bbts. This should only happen once.
1053 if (update && td->reserved_block_code)
1054 nand_update_bbt(mtd, (loff_t)(block - 2) << (this->bbt_erase_shift - 1));
1059 * verify_bbt_descr - verify the bad block description
1060 * @mtd: MTD device structure
1061 * @bd: the table to verify
1063 * This functions performs a few sanity checks on the bad block description
1066 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1068 struct nand_chip *this = mtd->priv;
1076 pattern_len = bd->len;
1077 bits = bd->options & NAND_BBT_NRBITS_MSK;
1079 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1080 !(this->bbt_options & NAND_BBT_USE_FLASH));
1083 if (bd->options & NAND_BBT_VERSION)
1086 if (bd->options & NAND_BBT_NO_OOB) {
1087 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1088 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1090 if (bd->options & NAND_BBT_VERSION)
1091 BUG_ON(bd->veroffs != bd->len);
1092 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1095 if (bd->options & NAND_BBT_PERCHIP)
1096 table_size = this->chipsize >> this->bbt_erase_shift;
1098 table_size = mtd->size >> this->bbt_erase_shift;
1101 if (bd->options & NAND_BBT_NO_OOB)
1102 table_size += pattern_len;
1103 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1107 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1108 * @mtd: MTD device structure
1109 * @bd: descriptor for the good/bad block search pattern
1111 * The function checks, if a bad block table(s) is/are already available. If
1112 * not it scans the device for manufacturer marked good / bad blocks and writes
1113 * the bad block table(s) to the selected place.
1115 * The bad block table memory is allocated here. It must be freed by calling
1116 * the nand_free_bbt function.
1118 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1120 struct nand_chip *this = mtd->priv;
1123 struct nand_bbt_descr *td = this->bbt_td;
1124 struct nand_bbt_descr *md = this->bbt_md;
1126 len = mtd->size >> (this->bbt_erase_shift + 2);
1128 * Allocate memory (2bit per block) and clear the memory bad block
1131 this->bbt = kzalloc(len, GFP_KERNEL);
1136 * If no primary table decriptor is given, scan the device to build a
1137 * memory based bad block table.
1140 if ((res = nand_memory_bbt(mtd, bd))) {
1141 pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1147 verify_bbt_descr(mtd, td);
1148 verify_bbt_descr(mtd, md);
1150 /* Allocate a temporary buffer for one eraseblock incl. oob */
1151 len = (1 << this->bbt_erase_shift);
1152 len += (len >> this->page_shift) * mtd->oobsize;
1160 /* Is the bbt at a given page? */
1161 if (td->options & NAND_BBT_ABSPAGE) {
1162 res = read_abs_bbts(mtd, buf, td, md);
1164 /* Search the bad block table using a pattern in oob */
1165 res = search_read_bbts(mtd, buf, td, md);
1169 res = check_create(mtd, buf, bd);
1171 /* Prevent the bbt regions from erasing / writing */
1172 mark_bbt_region(mtd, td);
1174 mark_bbt_region(mtd, md);
1181 * nand_update_bbt - [NAND Interface] update bad block table(s)
1182 * @mtd: MTD device structure
1183 * @offs: the offset of the newly marked block
1185 * The function updates the bad block table(s).
1187 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1189 struct nand_chip *this = mtd->priv;
1193 struct nand_bbt_descr *td = this->bbt_td;
1194 struct nand_bbt_descr *md = this->bbt_md;
1196 if (!this->bbt || !td)
1199 /* Allocate a temporary buffer for one eraseblock incl. oob */
1200 len = (1 << this->bbt_erase_shift);
1201 len += (len >> this->page_shift) * mtd->oobsize;
1202 buf = kmalloc(len, GFP_KERNEL);
1206 /* Do we have a bbt per chip? */
1207 if (td->options & NAND_BBT_PERCHIP) {
1208 chip = (int)(offs >> this->chip_shift);
1215 td->version[chip]++;
1217 md->version[chip]++;
1219 /* Write the bad block table to the device? */
1220 if (td->options & NAND_BBT_WRITE) {
1221 res = write_bbt(mtd, buf, td, md, chipsel);
1225 /* Write the mirror bad block table to the device? */
1226 if (md && (md->options & NAND_BBT_WRITE)) {
1227 res = write_bbt(mtd, buf, md, td, chipsel);
1236 * Define some generic bad / good block scan pattern which are used
1237 * while scanning a device for factory marked good / bad blocks.
1239 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1241 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1243 static struct nand_bbt_descr agand_flashbased = {
1244 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1247 .pattern = scan_agand_pattern
1250 /* Generic flash bbt descriptors */
1251 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1252 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1254 static struct nand_bbt_descr bbt_main_descr = {
1255 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1256 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1261 .pattern = bbt_pattern
1264 static struct nand_bbt_descr bbt_mirror_descr = {
1265 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1266 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1271 .pattern = mirror_pattern
1274 static struct nand_bbt_descr bbt_main_no_oob_descr = {
1275 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1276 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1281 .pattern = bbt_pattern
1284 static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
1285 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1286 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1291 .pattern = mirror_pattern
1294 #define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1296 * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1297 * @this: NAND chip to create descriptor for
1299 * This function allocates and initializes a nand_bbt_descr for BBM detection
1300 * based on the properties of @this. The new descriptor is stored in
1301 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1302 * passed to this function.
1304 static int nand_create_badblock_pattern(struct nand_chip *this)
1306 struct nand_bbt_descr *bd;
1307 if (this->badblock_pattern) {
1308 pr_warn("Bad block pattern already allocated; not replacing\n");
1311 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1314 bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1315 bd->offs = this->badblockpos;
1316 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1317 bd->pattern = scan_ff_pattern;
1318 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1319 this->badblock_pattern = bd;
1324 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1325 * @mtd: MTD device structure
1327 * This function selects the default bad block table support for the device and
1328 * calls the nand_scan_bbt function.
1330 int nand_default_bbt(struct mtd_info *mtd)
1332 struct nand_chip *this = mtd->priv;
1335 * Default for AG-AND. We must use a flash based bad block table as the
1336 * devices have factory marked _good_ blocks. Erasing those blocks
1337 * leads to loss of the good / bad information, so we _must_ store this
1338 * information in a good / bad table during startup.
1340 if (this->options & NAND_IS_AND) {
1341 /* Use the default pattern descriptors */
1342 if (!this->bbt_td) {
1343 this->bbt_td = &bbt_main_descr;
1344 this->bbt_md = &bbt_mirror_descr;
1346 this->bbt_options |= NAND_BBT_USE_FLASH;
1347 return nand_scan_bbt(mtd, &agand_flashbased);
1350 /* Is a flash based bad block table requested? */
1351 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1352 /* Use the default pattern descriptors */
1353 if (!this->bbt_td) {
1354 if (this->bbt_options & NAND_BBT_NO_OOB) {
1355 this->bbt_td = &bbt_main_no_oob_descr;
1356 this->bbt_md = &bbt_mirror_no_oob_descr;
1358 this->bbt_td = &bbt_main_descr;
1359 this->bbt_md = &bbt_mirror_descr;
1363 this->bbt_td = NULL;
1364 this->bbt_md = NULL;
1367 if (!this->badblock_pattern)
1368 nand_create_badblock_pattern(this);
1370 return nand_scan_bbt(mtd, this->badblock_pattern);
1374 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1375 * @mtd: MTD device structure
1376 * @offs: offset in the device
1377 * @allowbbt: allow access to bad block table region
1379 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1381 struct nand_chip *this = mtd->priv;
1385 /* Get block number * 2 */
1386 block = (int)(offs >> (this->bbt_erase_shift - 1));
1387 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1389 pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: "
1390 "(block %d) 0x%02x\n",
1391 (unsigned int)offs, block >> 1, res);
1399 return allowbbt ? 0 : 1;
1404 EXPORT_SYMBOL(nand_scan_bbt);
1405 EXPORT_SYMBOL(nand_default_bbt);