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27 * If one of the BBTs is out of date or does not exist it is (re)created.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, 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);
208 printk(KERN_INFO "nand_bbt: Error reading bad block table\n");
211 printk(KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
215 for (i = 0; i < len; i++) {
216 uint8_t dat = buf[i];
217 for (j = 0; j < 8; j += bits, act += 2) {
218 uint8_t tmp = (dat >> j) & msk;
221 if (reserved_block_code && (tmp == reserved_block_code)) {
222 printk(KERN_DEBUG "nand_read_bbt: Reserved block at 0x%012llx\n",
223 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
224 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
225 mtd->ecc_stats.bbtblocks++;
229 * Leave it for now, if it's matured we can
230 * move this message to MTD_DEBUG_LEVEL0.
232 printk(KERN_DEBUG "nand_read_bbt: Bad block at 0x%012llx\n",
233 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
234 /* Factory marked bad or worn out? */
236 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
238 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
239 mtd->ecc_stats.badblocks++;
249 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
250 * @mtd: MTD device structure
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; aplies only if
254 * NAND_BBT_PERCHIP option is set
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.
259 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
261 struct nand_chip *this = mtd->priv;
264 if (td->options & NAND_BBT_PERCHIP) {
266 for (i = 0; i < this->numchips; i++) {
267 if (chip == -1 || chip == i)
268 res = read_bbt(mtd, buf, td->pages[i],
269 this->chipsize >> this->bbt_erase_shift,
273 offs += this->chipsize >> (this->bbt_erase_shift + 2);
276 res = read_bbt(mtd, buf, td->pages[0],
277 mtd->size >> this->bbt_erase_shift, td, 0);
284 /* BBT marker is in the first page, no OOB */
285 static int scan_read_raw_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
286 struct nand_bbt_descr *td)
292 if (td->options & NAND_BBT_VERSION)
295 return mtd->read(mtd, offs, len, &retlen, buf);
298 /* Scan read raw data from flash */
299 static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
302 struct mtd_oob_ops ops;
305 ops.mode = MTD_OOB_RAW;
307 ops.ooblen = mtd->oobsize;
311 if (len <= mtd->writesize) {
312 ops.oobbuf = buf + len;
315 return mtd->read_oob(mtd, offs, &ops);
317 ops.oobbuf = buf + mtd->writesize;
319 ops.len = mtd->writesize;
320 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_OOB_PLACE;
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 printk(KERN_DEBUG "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 printk(KERN_DEBUG "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);
412 for (j = 0; j < len; j++, buf += scanlen) {
413 if (check_pattern(buf, scanlen, mtd->writesize, bd))
419 /* Scan a given block partially */
420 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
421 loff_t offs, uint8_t *buf, int len)
423 struct mtd_oob_ops ops;
426 ops.ooblen = mtd->oobsize;
430 ops.mode = MTD_OOB_PLACE;
432 for (j = 0; j < len; j++) {
434 * Read the full oob until read_oob is fixed to handle single
435 * byte reads for 16 bit buswidth.
437 ret = mtd->read_oob(mtd, offs, &ops);
441 if (check_short_pattern(buf, bd))
444 offs += mtd->writesize;
450 * create_bbt - [GENERIC] Create a bad block table by scanning the device
451 * @mtd: MTD device structure
452 * @buf: temporary buffer
453 * @bd: descriptor for the good/bad block search pattern
454 * @chip: create the table for a specific chip, -1 read all chips; applies only
455 * if NAND_BBT_PERCHIP option is set
457 * Create a bad block table by scanning the device for the given good/bad block
460 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
461 struct nand_bbt_descr *bd, int chip)
463 struct nand_chip *this = mtd->priv;
464 int i, numblocks, len, scanlen;
469 printk(KERN_INFO "Scanning device for bad blocks\n");
471 if (bd->options & NAND_BBT_SCANALLPAGES)
472 len = 1 << (this->bbt_erase_shift - this->page_shift);
473 else if (bd->options & NAND_BBT_SCAN2NDPAGE)
478 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
479 /* We need only read few bytes from the OOB area */
483 /* Full page content should be read */
484 scanlen = mtd->writesize + mtd->oobsize;
485 readlen = len * mtd->writesize;
490 * Note that numblocks is 2 * (real numblocks) here, see i+=2
491 * below as it makes shifting and masking less painful
493 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
497 if (chip >= this->numchips) {
498 printk(KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
499 chip + 1, this->numchips);
502 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
503 startblock = chip * numblocks;
504 numblocks += startblock;
505 from = (loff_t)startblock << (this->bbt_erase_shift - 1);
508 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
509 from += mtd->erasesize - (mtd->writesize * len);
511 for (i = startblock; i < numblocks;) {
514 BUG_ON(bd->options & NAND_BBT_NO_OOB);
516 if (bd->options & NAND_BBT_SCANALLPAGES)
517 ret = scan_block_full(mtd, bd, from, buf, readlen,
520 ret = scan_block_fast(mtd, bd, from, buf, len);
526 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
527 printk(KERN_WARNING "Bad eraseblock %d at 0x%012llx\n",
528 i >> 1, (unsigned long long)from);
529 mtd->ecc_stats.badblocks++;
533 from += (1 << this->bbt_erase_shift);
539 * search_bbt - [GENERIC] scan the device for a specific bad block table
540 * @mtd: MTD device structure
541 * @buf: temporary buffer
542 * @td: descriptor for the bad block table
544 * Read the bad block table by searching for a given ident pattern. Search is
545 * preformed either from the beginning up or from the end of the device
546 * downwards. The search starts always at the start of a block. If the option
547 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
548 * the bad block information of this chip. This is necessary to provide support
549 * for certain DOC devices.
551 * The bbt ident pattern resides in the oob area of the first page in a block.
553 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
555 struct nand_chip *this = mtd->priv;
557 int bits, startblock, block, dir;
558 int scanlen = mtd->writesize + mtd->oobsize;
560 int blocktopage = this->bbt_erase_shift - this->page_shift;
562 /* Search direction top -> down? */
563 if (td->options & NAND_BBT_LASTBLOCK) {
564 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
571 /* Do we have a bbt per chip? */
572 if (td->options & NAND_BBT_PERCHIP) {
573 chips = this->numchips;
574 bbtblocks = this->chipsize >> this->bbt_erase_shift;
575 startblock &= bbtblocks - 1;
578 bbtblocks = mtd->size >> this->bbt_erase_shift;
581 /* Number of bits for each erase block in the bbt */
582 bits = td->options & NAND_BBT_NRBITS_MSK;
584 for (i = 0; i < chips; i++) {
585 /* Reset version information */
588 /* Scan the maximum number of blocks */
589 for (block = 0; block < td->maxblocks; block++) {
591 int actblock = startblock + dir * block;
592 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
594 /* Read first page */
595 scan_read_raw(mtd, buf, offs, mtd->writesize, td);
596 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
597 td->pages[i] = actblock << blocktopage;
598 if (td->options & NAND_BBT_VERSION) {
599 offs = bbt_get_ver_offs(mtd, td);
600 td->version[i] = buf[offs];
605 startblock += this->chipsize >> this->bbt_erase_shift;
607 /* Check, if we found a bbt for each requested chip */
608 for (i = 0; i < chips; i++) {
609 if (td->pages[i] == -1)
610 printk(KERN_WARNING "Bad block table not found for chip %d\n", i);
612 printk(KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i],
619 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
620 * @mtd: MTD device structure
621 * @buf: temporary buffer
622 * @td: descriptor for the bad block table
623 * @md: descriptor for the bad block table mirror
625 * Search and read the bad block table(s).
627 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
629 /* Search the primary table */
630 search_bbt(mtd, buf, td);
632 /* Search the mirror table */
634 search_bbt(mtd, buf, md);
636 /* Force result check */
641 * write_bbt - [GENERIC] (Re)write the bad block table
642 * @mtd: MTD device structure
643 * @buf: temporary buffer
644 * @td: descriptor for the bad block table
645 * @md: descriptor for the bad block table mirror
646 * @chipsel: selector for a specific chip, -1 for all
648 * (Re)write the bad block table.
650 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
651 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
654 struct nand_chip *this = mtd->priv;
655 struct erase_info einfo;
656 int i, j, res, chip = 0;
657 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
658 int nrchips, bbtoffs, pageoffs, ooboffs;
660 uint8_t rcode = td->reserved_block_code;
661 size_t retlen, len = 0;
663 struct mtd_oob_ops ops;
665 ops.ooblen = mtd->oobsize;
668 ops.mode = MTD_OOB_PLACE;
672 /* Write bad block table per chip rather than per device? */
673 if (td->options & NAND_BBT_PERCHIP) {
674 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
675 /* Full device write or specific chip? */
677 nrchips = this->numchips;
679 nrchips = chipsel + 1;
683 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
687 /* Loop through the chips */
688 for (; chip < nrchips; chip++) {
690 * There was already a version of the table, reuse the page
691 * This applies for absolute placement too, as we have the
692 * page nr. in td->pages.
694 if (td->pages[chip] != -1) {
695 page = td->pages[chip];
700 * Automatic placement of the bad block table. Search direction
703 if (td->options & NAND_BBT_LASTBLOCK) {
704 startblock = numblocks * (chip + 1) - 1;
707 startblock = chip * numblocks;
711 for (i = 0; i < td->maxblocks; i++) {
712 int block = startblock + dir * i;
713 /* Check, if the block is bad */
714 switch ((this->bbt[block >> 2] >>
715 (2 * (block & 0x03))) & 0x03) {
721 (this->bbt_erase_shift - this->page_shift);
722 /* Check, if the block is used by the mirror table */
723 if (!md || md->pages[chip] != page)
726 printk(KERN_ERR "No space left to write bad block table\n");
730 /* Set up shift count and masks for the flash table */
731 bits = td->options & NAND_BBT_NRBITS_MSK;
734 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
737 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
740 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
743 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
746 default: return -EINVAL;
749 bbtoffs = chip * (numblocks >> 2);
751 to = ((loff_t) page) << this->page_shift;
753 /* Must we save the block contents? */
754 if (td->options & NAND_BBT_SAVECONTENT) {
755 /* Make it block aligned */
756 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
757 len = 1 << this->bbt_erase_shift;
758 res = mtd->read(mtd, to, len, &retlen, buf);
761 printk(KERN_INFO "nand_bbt: Error "
762 "reading block for writing "
763 "the bad block table\n");
766 printk(KERN_WARNING "nand_bbt: ECC error "
767 "while reading block for writing "
768 "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 printk(KERN_DEBUG "Bad block table written to 0x%012llx, version "
844 "0x%02X\n", (unsigned long long)to, td->version[chip]);
846 /* Mark it as used */
847 td->pages[chip] = page;
853 "nand_bbt: Error while writing bad block table %d\n", res);
858 * nand_memory_bbt - [GENERIC] create a memory based bad block table
859 * @mtd: MTD device structure
860 * @bd: descriptor for the good/bad block search pattern
862 * The function creates a memory based bbt by scanning the device for
863 * manufacturer / software marked good / bad blocks.
865 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
867 struct nand_chip *this = mtd->priv;
869 bd->options &= ~NAND_BBT_SCANEMPTY;
870 return create_bbt(mtd, this->buffers->databuf, bd, -1);
874 * check_create - [GENERIC] create and write bbt(s) if necessary
875 * @mtd: MTD device structure
876 * @buf: temporary buffer
877 * @bd: descriptor for the good/bad block search pattern
879 * The function checks the results of the previous call to read_bbt and creates
880 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
881 * for the chip/device. Update is necessary if one of the tables is missing or
882 * the version nr. of one table is less than the other.
884 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
886 int i, chips, writeops, chipsel, res;
887 struct nand_chip *this = mtd->priv;
888 struct nand_bbt_descr *td = this->bbt_td;
889 struct nand_bbt_descr *md = this->bbt_md;
890 struct nand_bbt_descr *rd, *rd2;
892 /* Do we have a bbt per chip? */
893 if (td->options & NAND_BBT_PERCHIP)
894 chips = this->numchips;
898 for (i = 0; i < chips; i++) {
902 /* Per chip or per device? */
903 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
904 /* Mirrored table available? */
906 if (td->pages[i] == -1 && md->pages[i] == -1) {
911 if (td->pages[i] == -1) {
913 td->version[i] = md->version[i];
918 if (md->pages[i] == -1) {
920 md->version[i] = td->version[i];
925 if (td->version[i] == md->version[i]) {
927 if (!(td->options & NAND_BBT_VERSION))
932 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
934 md->version[i] = td->version[i];
938 td->version[i] = md->version[i];
945 if (td->pages[i] == -1) {
953 /* Create the bad block table by scanning the device? */
954 if (!(td->options & NAND_BBT_CREATE))
957 /* Create the table in memory by scanning the chip(s) */
958 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
959 create_bbt(mtd, buf, bd, chipsel);
965 /* Read back first? */
967 read_abs_bbt(mtd, buf, rd, chipsel);
968 /* If they weren't versioned, read both */
970 read_abs_bbt(mtd, buf, rd2, chipsel);
972 /* Write the bad block table to the device? */
973 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
974 res = write_bbt(mtd, buf, td, md, chipsel);
979 /* Write the mirror bad block table to the device? */
980 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
981 res = write_bbt(mtd, buf, md, td, chipsel);
990 * mark_bbt_regions - [GENERIC] mark the bad block table regions
991 * @mtd: MTD device structure
992 * @td: bad block table descriptor
994 * The bad block table regions are marked as "bad" to prevent accidental
995 * erasures / writes. The regions are identified by the mark 0x02.
997 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
999 struct nand_chip *this = mtd->priv;
1000 int i, j, chips, block, nrblocks, update;
1001 uint8_t oldval, newval;
1003 /* Do we have a bbt per chip? */
1004 if (td->options & NAND_BBT_PERCHIP) {
1005 chips = this->numchips;
1006 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
1009 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1012 for (i = 0; i < chips; i++) {
1013 if ((td->options & NAND_BBT_ABSPAGE) ||
1014 !(td->options & NAND_BBT_WRITE)) {
1015 if (td->pages[i] == -1)
1017 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1019 oldval = this->bbt[(block >> 3)];
1020 newval = oldval | (0x2 << (block & 0x06));
1021 this->bbt[(block >> 3)] = newval;
1022 if ((oldval != newval) && td->reserved_block_code)
1023 nand_update_bbt(mtd, (loff_t)block << (this->bbt_erase_shift - 1));
1027 if (td->options & NAND_BBT_LASTBLOCK)
1028 block = ((i + 1) * nrblocks) - td->maxblocks;
1030 block = i * nrblocks;
1032 for (j = 0; j < td->maxblocks; j++) {
1033 oldval = this->bbt[(block >> 3)];
1034 newval = oldval | (0x2 << (block & 0x06));
1035 this->bbt[(block >> 3)] = newval;
1036 if (oldval != newval)
1041 * If we want reserved blocks to be recorded to flash, and some
1042 * new ones have been marked, then we need to update the stored
1043 * bbts. This should only happen once.
1045 if (update && td->reserved_block_code)
1046 nand_update_bbt(mtd, (loff_t)(block - 2) << (this->bbt_erase_shift - 1));
1051 * verify_bbt_descr - verify the bad block description
1052 * @mtd: MTD device structure
1053 * @bd: the table to verify
1055 * This functions performs a few sanity checks on the bad block description
1058 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1060 struct nand_chip *this = mtd->priv;
1068 pattern_len = bd->len;
1069 bits = bd->options & NAND_BBT_NRBITS_MSK;
1071 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1072 !(this->bbt_options & NAND_BBT_USE_FLASH));
1075 if (bd->options & NAND_BBT_VERSION)
1078 if (bd->options & NAND_BBT_NO_OOB) {
1079 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1080 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1082 if (bd->options & NAND_BBT_VERSION)
1083 BUG_ON(bd->veroffs != bd->len);
1084 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1087 if (bd->options & NAND_BBT_PERCHIP)
1088 table_size = this->chipsize >> this->bbt_erase_shift;
1090 table_size = mtd->size >> this->bbt_erase_shift;
1093 if (bd->options & NAND_BBT_NO_OOB)
1094 table_size += pattern_len;
1095 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1099 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1100 * @mtd: MTD device structure
1101 * @bd: descriptor for the good/bad block search pattern
1103 * The function checks, if a bad block table(s) is/are already available. If
1104 * not it scans the device for manufacturer marked good / bad blocks and writes
1105 * the bad block table(s) to the selected place.
1107 * The bad block table memory is allocated here. It must be freed by calling
1108 * the nand_free_bbt function.
1110 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1112 struct nand_chip *this = mtd->priv;
1115 struct nand_bbt_descr *td = this->bbt_td;
1116 struct nand_bbt_descr *md = this->bbt_md;
1118 len = mtd->size >> (this->bbt_erase_shift + 2);
1120 * Allocate memory (2bit per block) and clear the memory bad block
1123 this->bbt = kzalloc(len, GFP_KERNEL);
1128 * If no primary table decriptor is given, scan the device to build a
1129 * memory based bad block table.
1132 if ((res = nand_memory_bbt(mtd, bd))) {
1133 printk(KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
1139 verify_bbt_descr(mtd, td);
1140 verify_bbt_descr(mtd, md);
1142 /* Allocate a temporary buffer for one eraseblock incl. oob */
1143 len = (1 << this->bbt_erase_shift);
1144 len += (len >> this->page_shift) * mtd->oobsize;
1152 /* Is the bbt at a given page? */
1153 if (td->options & NAND_BBT_ABSPAGE) {
1154 res = read_abs_bbts(mtd, buf, td, md);
1156 /* Search the bad block table using a pattern in oob */
1157 res = search_read_bbts(mtd, buf, td, md);
1161 res = check_create(mtd, buf, bd);
1163 /* Prevent the bbt regions from erasing / writing */
1164 mark_bbt_region(mtd, td);
1166 mark_bbt_region(mtd, md);
1173 * nand_update_bbt - [NAND Interface] update bad block table(s)
1174 * @mtd: MTD device structure
1175 * @offs: the offset of the newly marked block
1177 * The function updates the bad block table(s).
1179 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1181 struct nand_chip *this = mtd->priv;
1182 int len, res = 0, writeops = 0;
1185 struct nand_bbt_descr *td = this->bbt_td;
1186 struct nand_bbt_descr *md = this->bbt_md;
1188 if (!this->bbt || !td)
1191 /* Allocate a temporary buffer for one eraseblock incl. oob */
1192 len = (1 << this->bbt_erase_shift);
1193 len += (len >> this->page_shift) * mtd->oobsize;
1194 buf = kmalloc(len, GFP_KERNEL);
1198 writeops = md != NULL ? 0x03 : 0x01;
1200 /* Do we have a bbt per chip? */
1201 if (td->options & NAND_BBT_PERCHIP) {
1202 chip = (int)(offs >> this->chip_shift);
1209 td->version[chip]++;
1211 md->version[chip]++;
1213 /* Write the bad block table to the device? */
1214 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1215 res = write_bbt(mtd, buf, td, md, chipsel);
1219 /* Write the mirror bad block table to the device? */
1220 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1221 res = write_bbt(mtd, buf, md, td, chipsel);
1230 * Define some generic bad / good block scan pattern which are used
1231 * while scanning a device for factory marked good / bad blocks.
1233 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1235 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1237 static struct nand_bbt_descr agand_flashbased = {
1238 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1241 .pattern = scan_agand_pattern
1244 /* Generic flash bbt descriptors */
1245 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1246 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1248 static struct nand_bbt_descr bbt_main_descr = {
1249 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1250 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1255 .pattern = bbt_pattern
1258 static struct nand_bbt_descr bbt_mirror_descr = {
1259 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1260 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1265 .pattern = mirror_pattern
1268 static struct nand_bbt_descr bbt_main_no_bbt_descr = {
1269 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1270 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1275 .pattern = bbt_pattern
1278 static struct nand_bbt_descr bbt_mirror_no_bbt_descr = {
1279 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1280 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1285 .pattern = mirror_pattern
1289 * nand_create_default_bbt_descr - [INTERN] Creates a BBT descriptor structure
1290 * @this: NAND chip to create descriptor for
1292 * This function allocates and initializes a nand_bbt_descr for BBM detection
1293 * based on the properties of "this". The new descriptor is stored in
1294 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1295 * passed to this function.
1297 static int nand_create_default_bbt_descr(struct nand_chip *this)
1299 struct nand_bbt_descr *bd;
1300 if (this->badblock_pattern) {
1301 printk(KERN_WARNING "BBT descr already allocated; not replacing.\n");
1304 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1307 bd->options = this->bbt_options;
1308 bd->offs = this->badblockpos;
1309 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1310 bd->pattern = scan_ff_pattern;
1311 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1312 this->badblock_pattern = bd;
1317 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1318 * @mtd: MTD device structure
1320 * This function selects the default bad block table support for the device and
1321 * calls the nand_scan_bbt function.
1323 int nand_default_bbt(struct mtd_info *mtd)
1325 struct nand_chip *this = mtd->priv;
1328 * Default for AG-AND. We must use a flash based bad block table as the
1329 * devices have factory marked _good_ blocks. Erasing those blocks
1330 * leads to loss of the good / bad information, so we _must_ store this
1331 * information in a good / bad table during startup.
1333 if (this->options & NAND_IS_AND) {
1334 /* Use the default pattern descriptors */
1335 if (!this->bbt_td) {
1336 this->bbt_td = &bbt_main_descr;
1337 this->bbt_md = &bbt_mirror_descr;
1339 this->bbt_options |= NAND_BBT_USE_FLASH;
1340 return nand_scan_bbt(mtd, &agand_flashbased);
1343 /* Is a flash based bad block table requested? */
1344 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1345 /* Use the default pattern descriptors */
1346 if (!this->bbt_td) {
1347 if (this->bbt_options & NAND_BBT_NO_OOB) {
1348 this->bbt_td = &bbt_main_no_bbt_descr;
1349 this->bbt_md = &bbt_mirror_no_bbt_descr;
1351 this->bbt_td = &bbt_main_descr;
1352 this->bbt_md = &bbt_mirror_descr;
1356 this->bbt_td = NULL;
1357 this->bbt_md = NULL;
1360 if (!this->badblock_pattern)
1361 nand_create_default_bbt_descr(this);
1363 return nand_scan_bbt(mtd, this->badblock_pattern);
1367 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1368 * @mtd: MTD device structure
1369 * @offs: offset in the device
1370 * @allowbbt: allow access to bad block table region
1372 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1374 struct nand_chip *this = mtd->priv;
1378 /* Get block number * 2 */
1379 block = (int)(offs >> (this->bbt_erase_shift - 1));
1380 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1382 DEBUG(MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1383 (unsigned int)offs, block >> 1, res);
1391 return allowbbt ? 0 : 1;
1396 EXPORT_SYMBOL(nand_scan_bbt);
1397 EXPORT_SYMBOL(nand_default_bbt);