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 than 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27 * If one of the BBTs is out of date or does not exist it is (re)created.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>
71 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
75 ret = memcmp(buf, td->pattern, td->len);
82 * check_pattern - [GENERIC] check if a pattern is in the buffer
83 * @buf: the buffer to search
84 * @len: the length of buffer to search
85 * @paglen: the pagelength
86 * @td: search pattern descriptor
88 * Check for a pattern at the given place. Used to search bad block tables and
89 * good / bad block identifiers. If the SCAN_EMPTY option is set then check, if
90 * all bytes except the pattern area contain 0xff.
92 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
97 if (td->options & NAND_BBT_NO_OOB)
98 return check_pattern_no_oob(buf, td);
100 end = paglen + td->offs;
101 if (td->options & NAND_BBT_SCANEMPTY) {
102 for (i = 0; i < end; i++) {
109 /* Compare the pattern */
110 for (i = 0; i < td->len; i++) {
111 if (p[i] != td->pattern[i])
115 if (td->options & NAND_BBT_SCANEMPTY) {
118 for (i = end; i < len; i++) {
127 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
128 * @buf: the buffer to search
129 * @td: search pattern descriptor
131 * Check for a pattern at the given place. Used to search bad block tables and
132 * good / bad block identifiers. Same as check_pattern, but no optional empty
135 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
140 /* Compare the pattern */
141 for (i = 0; i < td->len; i++) {
142 if (p[td->offs + i] != td->pattern[i])
149 * add_marker_len - compute the length of the marker in data area
150 * @td: BBT descriptor used for computation
152 * The length will be 0 if the marker is located in OOB area.
154 static u32 add_marker_len(struct nand_bbt_descr *td)
158 if (!(td->options & NAND_BBT_NO_OOB))
162 if (td->options & NAND_BBT_VERSION)
168 * read_bbt - [GENERIC] Read the bad block table starting from page
169 * @mtd: MTD device structure
170 * @buf: temporary buffer
171 * @page: the starting page
172 * @num: the number of bbt descriptors to read
173 * @td: the bbt describtion table
174 * @offs: offset in the memory table
176 * Read the bad block table starting from page.
178 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
179 struct nand_bbt_descr *td, int offs)
181 int res, ret = 0, i, j, act = 0;
182 struct nand_chip *this = mtd->priv;
183 size_t retlen, len, totlen;
185 int bits = td->options & NAND_BBT_NRBITS_MSK;
186 uint8_t msk = (uint8_t)((1 << bits) - 1);
188 int reserved_block_code = td->reserved_block_code;
190 totlen = (num * bits) >> 3;
191 marker_len = add_marker_len(td);
192 from = ((loff_t)page) << this->page_shift;
195 len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
198 * In case the BBT marker is not in the OOB area it
199 * will be just in the first page.
205 res = mtd->read(mtd, from, len, &retlen, buf);
207 if (mtd_is_eccerr(res)) {
208 pr_info("nand_bbt: ECC error in BBT at "
209 "0x%012llx\n", from & ~mtd->writesize);
211 } else if (mtd_is_bitflip(res)) {
212 pr_info("nand_bbt: corrected error in BBT at "
213 "0x%012llx\n", from & ~mtd->writesize);
216 pr_info("nand_bbt: error reading BBT\n");
222 for (i = 0; i < len; i++) {
223 uint8_t dat = buf[i];
224 for (j = 0; j < 8; j += bits, act += 2) {
225 uint8_t tmp = (dat >> j) & msk;
228 if (reserved_block_code && (tmp == reserved_block_code)) {
229 pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
230 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
231 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
232 mtd->ecc_stats.bbtblocks++;
236 * Leave it for now, if it's matured we can
237 * move this message to pr_debug.
239 pr_info("nand_read_bbt: bad block at 0x%012llx\n",
240 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
241 /* Factory marked bad or worn out? */
243 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
245 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
246 mtd->ecc_stats.badblocks++;
256 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
257 * @mtd: MTD device structure
258 * @buf: temporary buffer
259 * @td: descriptor for the bad block table
260 * @chip: read the table for a specific chip, -1 read all chips; applies only if
261 * NAND_BBT_PERCHIP option is set
263 * Read the bad block table for all chips starting at a given page. We assume
264 * that the bbt bits are in consecutive order.
266 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
268 struct nand_chip *this = mtd->priv;
271 if (td->options & NAND_BBT_PERCHIP) {
273 for (i = 0; i < this->numchips; i++) {
274 if (chip == -1 || chip == i)
275 res = read_bbt(mtd, buf, td->pages[i],
276 this->chipsize >> this->bbt_erase_shift,
280 offs += this->chipsize >> (this->bbt_erase_shift + 2);
283 res = read_bbt(mtd, buf, td->pages[0],
284 mtd->size >> this->bbt_erase_shift, td, 0);
291 /* BBT marker is in the first page, no OOB */
292 static int scan_read_raw_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
293 struct nand_bbt_descr *td)
299 if (td->options & NAND_BBT_VERSION)
302 return mtd->read(mtd, offs, len, &retlen, buf);
305 /* Scan read raw data from flash */
306 static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
309 struct mtd_oob_ops ops;
312 ops.mode = MTD_OPS_RAW;
314 ops.ooblen = mtd->oobsize;
318 ops.len = min(len, (size_t)mtd->writesize);
319 ops.oobbuf = buf + ops.len;
321 res = mtd->read_oob(mtd, offs, &ops);
326 buf += mtd->oobsize + mtd->writesize;
327 len -= mtd->writesize;
332 static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
333 size_t len, struct nand_bbt_descr *td)
335 if (td->options & NAND_BBT_NO_OOB)
336 return scan_read_raw_data(mtd, buf, offs, td);
338 return scan_read_raw_oob(mtd, buf, offs, len);
341 /* Scan write data with oob to flash */
342 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
343 uint8_t *buf, uint8_t *oob)
345 struct mtd_oob_ops ops;
347 ops.mode = MTD_OPS_PLACE_OOB;
349 ops.ooblen = mtd->oobsize;
354 return mtd->write_oob(mtd, offs, &ops);
357 static u32 bbt_get_ver_offs(struct mtd_info *mtd, struct nand_bbt_descr *td)
359 u32 ver_offs = td->veroffs;
361 if (!(td->options & NAND_BBT_NO_OOB))
362 ver_offs += mtd->writesize;
367 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
368 * @mtd: MTD device structure
369 * @buf: temporary buffer
370 * @td: descriptor for the bad block table
371 * @md: descriptor for the bad block table mirror
373 * Read the bad block table(s) for all chips starting at a given page. We
374 * assume that the bbt bits are in consecutive order.
376 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
377 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
379 struct nand_chip *this = mtd->priv;
381 /* Read the primary version, if available */
382 if (td->options & NAND_BBT_VERSION) {
383 scan_read_raw(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
385 td->version[0] = buf[bbt_get_ver_offs(mtd, td)];
386 pr_info("Bad block table at page %d, version 0x%02X\n",
387 td->pages[0], td->version[0]);
390 /* Read the mirror version, if available */
391 if (md && (md->options & NAND_BBT_VERSION)) {
392 scan_read_raw(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
394 md->version[0] = buf[bbt_get_ver_offs(mtd, md)];
395 pr_info("Bad block table at page %d, version 0x%02X\n",
396 md->pages[0], md->version[0]);
401 /* Scan a given block full */
402 static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
403 loff_t offs, uint8_t *buf, size_t readlen,
404 int scanlen, int len)
408 ret = scan_read_raw_oob(mtd, buf, offs, readlen);
409 /* Ignore ECC errors when checking for BBM */
410 if (ret && !mtd_is_bitflip_or_eccerr(ret))
413 for (j = 0; j < len; j++, buf += scanlen) {
414 if (check_pattern(buf, scanlen, mtd->writesize, bd))
420 /* Scan a given block partially */
421 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
422 loff_t offs, uint8_t *buf, int len)
424 struct mtd_oob_ops ops;
427 ops.ooblen = mtd->oobsize;
431 ops.mode = MTD_OPS_PLACE_OOB;
433 for (j = 0; j < len; j++) {
435 * Read the full oob until read_oob is fixed to handle single
436 * byte reads for 16 bit buswidth.
438 ret = mtd->read_oob(mtd, offs, &ops);
439 /* Ignore ECC errors when checking for BBM */
440 if (ret && !mtd_is_bitflip_or_eccerr(ret))
443 if (check_short_pattern(buf, bd))
446 offs += mtd->writesize;
452 * create_bbt - [GENERIC] Create a bad block table by scanning the device
453 * @mtd: MTD device structure
454 * @buf: temporary buffer
455 * @bd: descriptor for the good/bad block search pattern
456 * @chip: create the table for a specific chip, -1 read all chips; applies only
457 * if NAND_BBT_PERCHIP option is set
459 * Create a bad block table by scanning the device for the given good/bad block
462 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
463 struct nand_bbt_descr *bd, int chip)
465 struct nand_chip *this = mtd->priv;
466 int i, numblocks, len, scanlen;
471 pr_info("Scanning device for bad blocks\n");
473 if (bd->options & NAND_BBT_SCANALLPAGES)
474 len = 1 << (this->bbt_erase_shift - this->page_shift);
475 else if (bd->options & NAND_BBT_SCAN2NDPAGE)
480 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
481 /* We need only read few bytes from the OOB area */
485 /* Full page content should be read */
486 scanlen = mtd->writesize + mtd->oobsize;
487 readlen = len * mtd->writesize;
492 * Note that numblocks is 2 * (real numblocks) here, see i+=2
493 * below as it makes shifting and masking less painful
495 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
499 if (chip >= this->numchips) {
500 pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
501 chip + 1, this->numchips);
504 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
505 startblock = chip * numblocks;
506 numblocks += startblock;
507 from = (loff_t)startblock << (this->bbt_erase_shift - 1);
510 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
511 from += mtd->erasesize - (mtd->writesize * len);
513 for (i = startblock; i < numblocks;) {
516 BUG_ON(bd->options & NAND_BBT_NO_OOB);
518 if (bd->options & NAND_BBT_SCANALLPAGES)
519 ret = scan_block_full(mtd, bd, from, buf, readlen,
522 ret = scan_block_fast(mtd, bd, from, buf, len);
528 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
529 pr_warn("Bad eraseblock %d at 0x%012llx\n",
530 i >> 1, (unsigned long long)from);
531 mtd->ecc_stats.badblocks++;
535 from += (1 << this->bbt_erase_shift);
541 * search_bbt - [GENERIC] scan the device for a specific bad block table
542 * @mtd: MTD device structure
543 * @buf: temporary buffer
544 * @td: descriptor for the bad block table
546 * Read the bad block table by searching for a given ident pattern. Search is
547 * preformed either from the beginning up or from the end of the device
548 * downwards. The search starts always at the start of a block. If the option
549 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
550 * the bad block information of this chip. This is necessary to provide support
551 * for certain DOC devices.
553 * The bbt ident pattern resides in the oob area of the first page in a block.
555 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
557 struct nand_chip *this = mtd->priv;
559 int bits, startblock, block, dir;
560 int scanlen = mtd->writesize + mtd->oobsize;
562 int blocktopage = this->bbt_erase_shift - this->page_shift;
564 /* Search direction top -> down? */
565 if (td->options & NAND_BBT_LASTBLOCK) {
566 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
573 /* Do we have a bbt per chip? */
574 if (td->options & NAND_BBT_PERCHIP) {
575 chips = this->numchips;
576 bbtblocks = this->chipsize >> this->bbt_erase_shift;
577 startblock &= bbtblocks - 1;
580 bbtblocks = mtd->size >> this->bbt_erase_shift;
583 /* Number of bits for each erase block in the bbt */
584 bits = td->options & NAND_BBT_NRBITS_MSK;
586 for (i = 0; i < chips; i++) {
587 /* Reset version information */
590 /* Scan the maximum number of blocks */
591 for (block = 0; block < td->maxblocks; block++) {
593 int actblock = startblock + dir * block;
594 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
596 /* Read first page */
597 scan_read_raw(mtd, 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(mtd, td);
602 td->version[i] = buf[offs];
607 startblock += this->chipsize >> this->bbt_erase_shift;
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);
614 pr_info("Bad block table found at page %d, version "
615 "0x%02X\n", td->pages[i], td->version[i]);
621 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
622 * @mtd: MTD device structure
623 * @buf: temporary buffer
624 * @td: descriptor for the bad block table
625 * @md: descriptor for the bad block table mirror
627 * Search and read the bad block table(s).
629 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
631 /* Search the primary table */
632 search_bbt(mtd, buf, td);
634 /* Search the mirror table */
636 search_bbt(mtd, buf, md);
638 /* Force result check */
643 * write_bbt - [GENERIC] (Re)write the bad block table
644 * @mtd: MTD device structure
645 * @buf: temporary buffer
646 * @td: descriptor for the bad block table
647 * @md: descriptor for the bad block table mirror
648 * @chipsel: selector for a specific chip, -1 for all
650 * (Re)write the bad block table.
652 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
653 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
656 struct nand_chip *this = mtd->priv;
657 struct erase_info einfo;
658 int i, j, res, chip = 0;
659 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
660 int nrchips, bbtoffs, pageoffs, ooboffs;
662 uint8_t rcode = td->reserved_block_code;
663 size_t retlen, len = 0;
665 struct mtd_oob_ops ops;
667 ops.ooblen = mtd->oobsize;
670 ops.mode = MTD_OPS_PLACE_OOB;
674 /* Write bad block table per chip rather than per device? */
675 if (td->options & NAND_BBT_PERCHIP) {
676 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
677 /* Full device write or specific chip? */
679 nrchips = this->numchips;
681 nrchips = chipsel + 1;
685 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
689 /* Loop through the chips */
690 for (; chip < nrchips; chip++) {
692 * There was already a version of the table, reuse the page
693 * This applies for absolute placement too, as we have the
694 * page nr. in td->pages.
696 if (td->pages[chip] != -1) {
697 page = td->pages[chip];
702 * Automatic placement of the bad block table. Search direction
705 if (td->options & NAND_BBT_LASTBLOCK) {
706 startblock = numblocks * (chip + 1) - 1;
709 startblock = chip * numblocks;
713 for (i = 0; i < td->maxblocks; i++) {
714 int block = startblock + dir * i;
715 /* Check, if the block is bad */
716 switch ((this->bbt[block >> 2] >>
717 (2 * (block & 0x03))) & 0x03) {
723 (this->bbt_erase_shift - this->page_shift);
724 /* Check, if the block is used by the mirror table */
725 if (!md || md->pages[chip] != page)
728 pr_err("No space left to write bad block table\n");
732 /* Set up shift count and masks for the flash table */
733 bits = td->options & NAND_BBT_NRBITS_MSK;
736 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
739 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
742 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
745 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
748 default: return -EINVAL;
751 bbtoffs = chip * (numblocks >> 2);
753 to = ((loff_t)page) << this->page_shift;
755 /* Must we save the block contents? */
756 if (td->options & NAND_BBT_SAVECONTENT) {
757 /* Make it block aligned */
758 to &= ~((loff_t)((1 << this->bbt_erase_shift) - 1));
759 len = 1 << this->bbt_erase_shift;
760 res = mtd->read(mtd, to, len, &retlen, buf);
763 pr_info("nand_bbt: error reading block "
764 "for writing the bad block table\n");
767 pr_warn("nand_bbt: ECC error while reading "
768 "block for writing bad block table\n");
771 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
772 ops.oobbuf = &buf[len];
773 res = mtd->read_oob(mtd, to + mtd->writesize, &ops);
774 if (res < 0 || ops.oobretlen != ops.ooblen)
777 /* Calc the byte offset in the buffer */
778 pageoffs = page - (int)(to >> this->page_shift);
779 offs = pageoffs << this->page_shift;
780 /* Preset the bbt area with 0xff */
781 memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
782 ooboffs = len + (pageoffs * mtd->oobsize);
784 } else if (td->options & NAND_BBT_NO_OOB) {
787 /* The version byte */
788 if (td->options & NAND_BBT_VERSION)
791 len = (size_t)(numblocks >> sft);
793 /* Make it page aligned! */
794 len = ALIGN(len, mtd->writesize);
795 /* Preset the buffer with 0xff */
796 memset(buf, 0xff, len);
797 /* Pattern is located at the begin of first page */
798 memcpy(buf, td->pattern, td->len);
801 len = (size_t)(numblocks >> sft);
802 /* Make it page aligned! */
803 len = ALIGN(len, mtd->writesize);
804 /* Preset the buffer with 0xff */
805 memset(buf, 0xff, len +
806 (len >> this->page_shift)* mtd->oobsize);
809 /* Pattern is located in oob area of first page */
810 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
813 if (td->options & NAND_BBT_VERSION)
814 buf[ooboffs + td->veroffs] = td->version[chip];
816 /* Walk through the memory table */
817 for (i = 0; i < numblocks;) {
819 dat = this->bbt[bbtoffs + (i >> 2)];
820 for (j = 0; j < 4; j++, i++) {
821 int sftcnt = (i << (3 - sft)) & sftmsk;
822 /* Do not store the reserved bbt blocks! */
823 buf[offs + (i >> sft)] &=
824 ~(msk[dat & 0x03] << sftcnt);
829 memset(&einfo, 0, sizeof(einfo));
832 einfo.len = 1 << this->bbt_erase_shift;
833 res = nand_erase_nand(mtd, &einfo, 1);
837 res = scan_write_bbt(mtd, to, len, buf,
838 td->options & NAND_BBT_NO_OOB ? NULL :
843 pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
844 (unsigned long long)to, td->version[chip]);
846 /* Mark it as used */
847 td->pages[chip] = page;
852 pr_warn("nand_bbt: error while writing bad block table %d\n", res);
857 * nand_memory_bbt - [GENERIC] create a memory based bad block table
858 * @mtd: MTD device structure
859 * @bd: descriptor for the good/bad block search pattern
861 * The function creates a memory based bbt by scanning the device for
862 * manufacturer / software marked good / bad blocks.
864 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
866 struct nand_chip *this = mtd->priv;
868 bd->options &= ~NAND_BBT_SCANEMPTY;
869 return create_bbt(mtd, this->buffers->databuf, bd, -1);
873 * check_create - [GENERIC] create and write bbt(s) if necessary
874 * @mtd: MTD device structure
875 * @buf: temporary buffer
876 * @bd: descriptor for the good/bad block search pattern
878 * The function checks the results of the previous call to read_bbt and creates
879 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
880 * for the chip/device. Update is necessary if one of the tables is missing or
881 * the version nr. of one table is less than the other.
883 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
885 int i, chips, writeops, create, chipsel, res, res2;
886 struct nand_chip *this = mtd->priv;
887 struct nand_bbt_descr *td = this->bbt_td;
888 struct nand_bbt_descr *md = this->bbt_md;
889 struct nand_bbt_descr *rd, *rd2;
891 /* Do we have a bbt per chip? */
892 if (td->options & NAND_BBT_PERCHIP)
893 chips = this->numchips;
897 for (i = 0; i < chips; i++) {
903 /* Per chip or per device? */
904 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
905 /* Mirrored table available? */
907 if (td->pages[i] == -1 && md->pages[i] == -1) {
910 } else if (td->pages[i] == -1) {
912 td->version[i] = md->version[i];
914 } else if (md->pages[i] == -1) {
916 md->version[i] = td->version[i];
918 } else if (td->version[i] == md->version[i]) {
920 if (!(td->options & NAND_BBT_VERSION))
922 } else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
924 md->version[i] = td->version[i];
928 td->version[i] = md->version[i];
932 if (td->pages[i] == -1) {
941 /* Create the bad block table by scanning the device? */
942 if (!(td->options & NAND_BBT_CREATE))
945 /* Create the table in memory by scanning the chip(s) */
946 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
947 create_bbt(mtd, buf, bd, chipsel);
954 /* Read back first? */
956 res = read_abs_bbt(mtd, buf, rd, chipsel);
957 if (mtd_is_eccerr(res)) {
958 /* Mark table as invalid */
964 /* If they weren't versioned, read both */
966 res2 = read_abs_bbt(mtd, buf, rd2, chipsel);
967 if (mtd_is_eccerr(res2)) {
968 /* Mark table as invalid */
975 /* Scrub the flash table(s)? */
976 if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
979 /* Write the bad block table to the device? */
980 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
981 res = write_bbt(mtd, buf, td, md, chipsel);
986 /* Write the mirror bad block table to the device? */
987 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
988 res = write_bbt(mtd, buf, md, td, chipsel);
997 * mark_bbt_regions - [GENERIC] mark the bad block table regions
998 * @mtd: MTD device structure
999 * @td: bad block table descriptor
1001 * The bad block table regions are marked as "bad" to prevent accidental
1002 * erasures / writes. The regions are identified by the mark 0x02.
1004 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
1006 struct nand_chip *this = mtd->priv;
1007 int i, j, chips, block, nrblocks, update;
1008 uint8_t oldval, newval;
1010 /* Do we have a bbt per chip? */
1011 if (td->options & NAND_BBT_PERCHIP) {
1012 chips = this->numchips;
1013 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
1016 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1019 for (i = 0; i < chips; i++) {
1020 if ((td->options & NAND_BBT_ABSPAGE) ||
1021 !(td->options & NAND_BBT_WRITE)) {
1022 if (td->pages[i] == -1)
1024 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1026 oldval = this->bbt[(block >> 3)];
1027 newval = oldval | (0x2 << (block & 0x06));
1028 this->bbt[(block >> 3)] = newval;
1029 if ((oldval != newval) && td->reserved_block_code)
1030 nand_update_bbt(mtd, (loff_t)block << (this->bbt_erase_shift - 1));
1034 if (td->options & NAND_BBT_LASTBLOCK)
1035 block = ((i + 1) * nrblocks) - td->maxblocks;
1037 block = i * nrblocks;
1039 for (j = 0; j < td->maxblocks; j++) {
1040 oldval = this->bbt[(block >> 3)];
1041 newval = oldval | (0x2 << (block & 0x06));
1042 this->bbt[(block >> 3)] = newval;
1043 if (oldval != newval)
1048 * If we want reserved blocks to be recorded to flash, and some
1049 * new ones have been marked, then we need to update the stored
1050 * bbts. This should only happen once.
1052 if (update && td->reserved_block_code)
1053 nand_update_bbt(mtd, (loff_t)(block - 2) << (this->bbt_erase_shift - 1));
1058 * verify_bbt_descr - verify the bad block description
1059 * @mtd: MTD device structure
1060 * @bd: the table to verify
1062 * This functions performs a few sanity checks on the bad block description
1065 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1067 struct nand_chip *this = mtd->priv;
1075 pattern_len = bd->len;
1076 bits = bd->options & NAND_BBT_NRBITS_MSK;
1078 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1079 !(this->bbt_options & NAND_BBT_USE_FLASH));
1082 if (bd->options & NAND_BBT_VERSION)
1085 if (bd->options & NAND_BBT_NO_OOB) {
1086 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1087 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1089 if (bd->options & NAND_BBT_VERSION)
1090 BUG_ON(bd->veroffs != bd->len);
1091 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1094 if (bd->options & NAND_BBT_PERCHIP)
1095 table_size = this->chipsize >> this->bbt_erase_shift;
1097 table_size = mtd->size >> this->bbt_erase_shift;
1100 if (bd->options & NAND_BBT_NO_OOB)
1101 table_size += pattern_len;
1102 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1106 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1107 * @mtd: MTD device structure
1108 * @bd: descriptor for the good/bad block search pattern
1110 * The function checks, if a bad block table(s) is/are already available. If
1111 * not it scans the device for manufacturer marked good / bad blocks and writes
1112 * the bad block table(s) to the selected place.
1114 * The bad block table memory is allocated here. It must be freed by calling
1115 * the nand_free_bbt function.
1117 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1119 struct nand_chip *this = mtd->priv;
1122 struct nand_bbt_descr *td = this->bbt_td;
1123 struct nand_bbt_descr *md = this->bbt_md;
1125 len = mtd->size >> (this->bbt_erase_shift + 2);
1127 * Allocate memory (2bit per block) and clear the memory bad block
1130 this->bbt = kzalloc(len, GFP_KERNEL);
1135 * If no primary table decriptor is given, scan the device to build a
1136 * memory based bad block table.
1139 if ((res = nand_memory_bbt(mtd, bd))) {
1140 pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1146 verify_bbt_descr(mtd, td);
1147 verify_bbt_descr(mtd, md);
1149 /* Allocate a temporary buffer for one eraseblock incl. oob */
1150 len = (1 << this->bbt_erase_shift);
1151 len += (len >> this->page_shift) * mtd->oobsize;
1159 /* Is the bbt at a given page? */
1160 if (td->options & NAND_BBT_ABSPAGE) {
1161 res = read_abs_bbts(mtd, buf, td, md);
1163 /* Search the bad block table using a pattern in oob */
1164 res = search_read_bbts(mtd, buf, td, md);
1168 res = check_create(mtd, buf, bd);
1170 /* Prevent the bbt regions from erasing / writing */
1171 mark_bbt_region(mtd, td);
1173 mark_bbt_region(mtd, md);
1180 * nand_update_bbt - [NAND Interface] update bad block table(s)
1181 * @mtd: MTD device structure
1182 * @offs: the offset of the newly marked block
1184 * The function updates the bad block table(s).
1186 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1188 struct nand_chip *this = mtd->priv;
1192 struct nand_bbt_descr *td = this->bbt_td;
1193 struct nand_bbt_descr *md = this->bbt_md;
1195 if (!this->bbt || !td)
1198 /* Allocate a temporary buffer for one eraseblock incl. oob */
1199 len = (1 << this->bbt_erase_shift);
1200 len += (len >> this->page_shift) * mtd->oobsize;
1201 buf = kmalloc(len, GFP_KERNEL);
1205 /* Do we have a bbt per chip? */
1206 if (td->options & NAND_BBT_PERCHIP) {
1207 chip = (int)(offs >> this->chip_shift);
1214 td->version[chip]++;
1216 md->version[chip]++;
1218 /* Write the bad block table to the device? */
1219 if (td->options & NAND_BBT_WRITE) {
1220 res = write_bbt(mtd, buf, td, md, chipsel);
1224 /* Write the mirror bad block table to the device? */
1225 if (md && (md->options & NAND_BBT_WRITE)) {
1226 res = write_bbt(mtd, buf, md, td, chipsel);
1235 * Define some generic bad / good block scan pattern which are used
1236 * while scanning a device for factory marked good / bad blocks.
1238 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1240 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1242 static struct nand_bbt_descr agand_flashbased = {
1243 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1246 .pattern = scan_agand_pattern
1249 /* Generic flash bbt descriptors */
1250 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1251 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1253 static struct nand_bbt_descr bbt_main_descr = {
1254 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1255 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1260 .pattern = bbt_pattern
1263 static struct nand_bbt_descr bbt_mirror_descr = {
1264 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1265 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1270 .pattern = mirror_pattern
1273 static struct nand_bbt_descr bbt_main_no_bbt_descr = {
1274 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1275 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1280 .pattern = bbt_pattern
1283 static struct nand_bbt_descr bbt_mirror_no_bbt_descr = {
1284 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1285 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1290 .pattern = mirror_pattern
1294 * nand_create_default_bbt_descr - [INTERN] Creates a BBT descriptor structure
1295 * @this: NAND chip to create descriptor for
1297 * This function allocates and initializes a nand_bbt_descr for BBM detection
1298 * based on the properties of "this". The new descriptor is stored in
1299 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1300 * passed to this function.
1302 static int nand_create_default_bbt_descr(struct nand_chip *this)
1304 struct nand_bbt_descr *bd;
1305 if (this->badblock_pattern) {
1306 pr_warn("BBT descr already allocated; not replacing\n");
1309 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1312 bd->options = this->bbt_options;
1313 bd->offs = this->badblockpos;
1314 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1315 bd->pattern = scan_ff_pattern;
1316 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1317 this->badblock_pattern = bd;
1322 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1323 * @mtd: MTD device structure
1325 * This function selects the default bad block table support for the device and
1326 * calls the nand_scan_bbt function.
1328 int nand_default_bbt(struct mtd_info *mtd)
1330 struct nand_chip *this = mtd->priv;
1333 * Default for AG-AND. We must use a flash based bad block table as the
1334 * devices have factory marked _good_ blocks. Erasing those blocks
1335 * leads to loss of the good / bad information, so we _must_ store this
1336 * information in a good / bad table during startup.
1338 if (this->options & NAND_IS_AND) {
1339 /* Use the default pattern descriptors */
1340 if (!this->bbt_td) {
1341 this->bbt_td = &bbt_main_descr;
1342 this->bbt_md = &bbt_mirror_descr;
1344 this->bbt_options |= NAND_BBT_USE_FLASH;
1345 return nand_scan_bbt(mtd, &agand_flashbased);
1348 /* Is a flash based bad block table requested? */
1349 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1350 /* Use the default pattern descriptors */
1351 if (!this->bbt_td) {
1352 if (this->bbt_options & NAND_BBT_NO_OOB) {
1353 this->bbt_td = &bbt_main_no_bbt_descr;
1354 this->bbt_md = &bbt_mirror_no_bbt_descr;
1356 this->bbt_td = &bbt_main_descr;
1357 this->bbt_md = &bbt_mirror_descr;
1361 this->bbt_td = NULL;
1362 this->bbt_md = NULL;
1365 if (!this->badblock_pattern)
1366 nand_create_default_bbt_descr(this);
1368 return nand_scan_bbt(mtd, this->badblock_pattern);
1372 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1373 * @mtd: MTD device structure
1374 * @offs: offset in the device
1375 * @allowbbt: allow access to bad block table region
1377 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1379 struct nand_chip *this = mtd->priv;
1383 /* Get block number * 2 */
1384 block = (int)(offs >> (this->bbt_erase_shift - 1));
1385 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1387 pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: "
1388 "(block %d) 0x%02x\n",
1389 (unsigned int)offs, block >> 1, res);
1397 return allowbbt ? 0 : 1;
1402 EXPORT_SYMBOL(nand_scan_bbt);
1403 EXPORT_SYMBOL(nand_default_bbt);