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 a bbt is found
17 * then the contents are read and the memory based bbt is created. If a
18 * mirrored bbt is selected then the mirror is searched too and the
19 * versions are compared. If the mirror has a greater version number
20 * than the mirror bbt is used to build the memory based bbt.
21 * If the tables are not versioned, then we "or" the bad block information.
22 * If one of the bbt's is out of date or does not exist it is (re)created.
23 * If no bbt exists at all then the device is scanned for factory marked
24 * good / bad blocks and the bad block tables are created.
26 * For manufacturer created bbts like the one found on M-SYS DOC devices
27 * the bbt is searched and read but never created
29 * The autogenerated bad block table is located in the last good blocks
30 * of the device. The table is mirrored, so it can be updated eventually.
31 * The table is marked in the oob area with an ident pattern and a version
32 * number which indicates which of both tables is more up to date.
34 * The table uses 2 bits per block
36 * 00b: block is factory marked bad
37 * 01b, 10b: block is marked bad due to wear
39 * The memory bad block table uses the following scheme:
41 * 01b: block is marked bad due to wear
42 * 10b: block is reserved (to protect the bbt area)
43 * 11b: block is factory marked bad
45 * Multichip devices like DOC store the bad block info per floor.
47 * Following assumptions are made:
48 * - bbts start at a page boundary, if autolocated on a block boundary
49 * - the space necessary for a bbt in FLASH does not exceed a block boundary
55 #include <linux/mtd/compat.h>
56 #include <linux/mtd/mtd.h>
57 #include <linux/mtd/nand.h>
59 #include <asm/errno.h>
63 #include <linux/slab.h>
64 #include <linux/types.h>
65 #include <linux/mtd/mtd.h>
66 #include <linux/mtd/nand.h>
67 #include <linux/mtd/nand_ecc.h>
68 #include <linux/mtd/compatmac.h>
69 #include <linux/bitops.h>
70 #include <linux/delay.h>
71 #include <linux/vmalloc.h>
75 * check_pattern - [GENERIC] check if a pattern is in the buffer
76 * @buf: the buffer to search
77 * @len: the length of buffer to search
78 * @paglen: the pagelength
79 * @td: search pattern descriptor
81 * Check for a pattern at the given place. Used to search bad block
82 * tables and good / bad block identifiers.
83 * If the SCAN_EMPTY option is set then check, if all bytes except the
84 * pattern area contain 0xff
87 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
92 end = paglen + td->offs;
93 if (td->options & NAND_BBT_SCANEMPTY) {
94 for (i = 0; i < end; i++) {
101 /* Compare the pattern */
102 for (i = 0; i < td->len; i++) {
103 if (p[i] != td->pattern[i])
107 if (td->options & NAND_BBT_SCANEMPTY) {
110 for (i = end; i < len; i++) {
119 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
120 * @buf: the buffer to search
121 * @td: search pattern descriptor
123 * Check for a pattern at the given place. Used to search bad block
124 * tables and good / bad block identifiers. Same as check_pattern, but
125 * no optional empty check
128 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
133 /* Compare the pattern */
134 for (i = 0; i < td->len; i++) {
135 if (p[td->offs + i] != td->pattern[i])
142 * read_bbt - [GENERIC] Read the bad block table starting from page
143 * @mtd: MTD device structure
144 * @buf: temporary buffer
145 * @page: the starting page
146 * @num: the number of bbt descriptors to read
147 * @bits: number of bits per block
148 * @offs: offset in the memory table
149 * @reserved_block_code: Pattern to identify reserved blocks
151 * Read the bad block table starting from page.
154 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
155 int bits, int offs, int reserved_block_code)
157 int res, i, j, act = 0;
158 struct nand_chip *this = mtd->priv;
159 size_t retlen, len, totlen;
161 uint8_t msk = (uint8_t) ((1 << bits) - 1);
163 totlen = (num * bits) >> 3;
164 from = ((loff_t) page) << this->page_shift;
167 len = min(totlen, (size_t) (1 << this->bbt_erase_shift));
168 res = mtd->read(mtd, from, len, &retlen, buf);
171 printk(KERN_INFO "nand_bbt: Error reading bad block table\n");
174 printk(KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
178 for (i = 0; i < len; i++) {
179 uint8_t dat = buf[i];
180 for (j = 0; j < 8; j += bits, act += 2) {
181 uint8_t tmp = (dat >> j) & msk;
184 if (reserved_block_code && (tmp == reserved_block_code)) {
185 printk(KERN_DEBUG "nand_read_bbt: Reserved block at 0x%012llx\n",
186 (loff_t)((offs << 2) +
188 this->bbt_erase_shift);
189 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
190 mtd->ecc_stats.bbtblocks++;
193 /* Leave it for now, if its matured we can move this
194 * message to MTD_DEBUG_LEVEL0 */
195 printk(KERN_DEBUG "nand_read_bbt: Bad block at 0x%012llx\n",
196 (loff_t)((offs << 2) + (act >> 1)) <<
197 this->bbt_erase_shift);
198 /* Factory marked bad or worn out ? */
200 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
202 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
203 mtd->ecc_stats.badblocks++;
213 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
214 * @mtd: MTD device structure
215 * @buf: temporary buffer
216 * @td: descriptor for the bad block table
217 * @chip: read the table for a specific chip, -1 read all chips.
218 * Applies only if NAND_BBT_PERCHIP option is set
220 * Read the bad block table for all chips starting at a given page
221 * We assume that the bbt bits are in consecutive order.
223 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
225 struct nand_chip *this = mtd->priv;
229 bits = td->options & NAND_BBT_NRBITS_MSK;
230 if (td->options & NAND_BBT_PERCHIP) {
232 for (i = 0; i < this->numchips; i++) {
233 if (chip == -1 || chip == i)
234 res = read_bbt (mtd, buf, td->pages[i], this->chipsize >> this->bbt_erase_shift, bits, offs, td->reserved_block_code);
237 offs += this->chipsize >> (this->bbt_erase_shift + 2);
240 res = read_bbt (mtd, buf, td->pages[0], mtd->size >> this->bbt_erase_shift, bits, 0, td->reserved_block_code);
248 * Scan read raw data from flash
250 static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
253 struct mtd_oob_ops ops;
255 ops.mode = MTD_OOB_RAW;
257 ops.ooblen = mtd->oobsize;
262 return mtd->read_oob(mtd, offs, &ops);
266 * Scan write data with oob to flash
268 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
269 uint8_t *buf, uint8_t *oob)
271 struct mtd_oob_ops ops;
273 ops.mode = MTD_OOB_PLACE;
275 ops.ooblen = mtd->oobsize;
280 return mtd->write_oob(mtd, offs, &ops);
284 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
285 * @mtd: MTD device structure
286 * @buf: temporary buffer
287 * @td: descriptor for the bad block table
288 * @md: descriptor for the bad block table mirror
290 * Read the bad block table(s) for all chips starting at a given page
291 * We assume that the bbt bits are in consecutive order.
294 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
295 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
297 struct nand_chip *this = mtd->priv;
299 /* Read the primary version, if available */
300 if (td->options & NAND_BBT_VERSION) {
301 scan_read_raw(mtd, buf, (loff_t)td->pages[0] <<
302 this->page_shift, mtd->writesize);
303 td->version[0] = buf[mtd->writesize + td->veroffs];
304 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
305 td->pages[0], td->version[0]);
308 /* Read the mirror version, if available */
309 if (md && (md->options & NAND_BBT_VERSION)) {
310 scan_read_raw(mtd, buf, (loff_t)md->pages[0] <<
311 this->page_shift, mtd->writesize);
312 md->version[0] = buf[mtd->writesize + md->veroffs];
313 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
314 md->pages[0], md->version[0]);
320 * Scan a given block full
322 static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
323 loff_t offs, uint8_t *buf, size_t readlen,
324 int scanlen, int len)
328 ret = scan_read_raw(mtd, buf, offs, readlen);
332 for (j = 0; j < len; j++, buf += scanlen) {
333 if (check_pattern(buf, scanlen, mtd->writesize, bd))
340 * Scan a given block partially
342 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
343 loff_t offs, uint8_t *buf, int len)
345 struct mtd_oob_ops ops;
348 ops.ooblen = mtd->oobsize;
352 ops.mode = MTD_OOB_PLACE;
354 for (j = 0; j < len; j++) {
356 * Read the full oob until read_oob is fixed to
357 * handle single byte reads for 16 bit
360 ret = mtd->read_oob(mtd, offs, &ops);
364 if (check_short_pattern(buf, bd))
367 offs += mtd->writesize;
373 * create_bbt - [GENERIC] Create a bad block table by scanning the device
374 * @mtd: MTD device structure
375 * @buf: temporary buffer
376 * @bd: descriptor for the good/bad block search pattern
377 * @chip: create the table for a specific chip, -1 read all chips.
378 * Applies only if NAND_BBT_PERCHIP option is set
380 * Create a bad block table by scanning the device
381 * for the given good/bad block identify pattern
383 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
384 struct nand_bbt_descr *bd, int chip)
386 struct nand_chip *this = mtd->priv;
387 int i, numblocks, len, scanlen;
392 MTDDEBUG (MTD_DEBUG_LEVEL0, "Scanning device for bad blocks\n");
394 if (bd->options & NAND_BBT_SCANALLPAGES)
395 len = 1 << (this->bbt_erase_shift - this->page_shift);
397 if (bd->options & NAND_BBT_SCAN2NDPAGE)
403 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
404 /* We need only read few bytes from the OOB area */
408 /* Full page content should be read */
409 scanlen = mtd->writesize + mtd->oobsize;
410 readlen = len * mtd->writesize;
414 /* Note that numblocks is 2 * (real numblocks) here, see i+=2
415 * below as it makes shifting and masking less painful */
416 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
420 if (chip >= this->numchips) {
421 printk(KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
422 chip + 1, this->numchips);
425 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
426 startblock = chip * numblocks;
427 numblocks += startblock;
428 from = (loff_t)startblock << (this->bbt_erase_shift - 1);
431 for (i = startblock; i < numblocks;) {
434 if (bd->options & NAND_BBT_SCANALLPAGES)
435 ret = scan_block_full(mtd, bd, from, buf, readlen,
438 ret = scan_block_fast(mtd, bd, from, buf, len);
444 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
445 MTDDEBUG (MTD_DEBUG_LEVEL0,
446 "Bad eraseblock %d at 0x%012llx\n",
447 i >> 1, (unsigned long long)from);
448 mtd->ecc_stats.badblocks++;
452 from += (1 << this->bbt_erase_shift);
458 * search_bbt - [GENERIC] scan the device for a specific bad block table
459 * @mtd: MTD device structure
460 * @buf: temporary buffer
461 * @td: descriptor for the bad block table
463 * Read the bad block table by searching for a given ident pattern.
464 * Search is preformed either from the beginning up or from the end of
465 * the device downwards. The search starts always at the start of a
467 * If the option NAND_BBT_PERCHIP is given, each chip is searched
468 * for a bbt, which contains the bad block information of this chip.
469 * This is necessary to provide support for certain DOC devices.
471 * The bbt ident pattern resides in the oob area of the first page
474 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
476 struct nand_chip *this = mtd->priv;
478 int bits, startblock, block, dir;
479 int scanlen = mtd->writesize + mtd->oobsize;
481 int blocktopage = this->bbt_erase_shift - this->page_shift;
483 /* Search direction top -> down ? */
484 if (td->options & NAND_BBT_LASTBLOCK) {
485 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
492 /* Do we have a bbt per chip ? */
493 if (td->options & NAND_BBT_PERCHIP) {
494 chips = this->numchips;
495 bbtblocks = this->chipsize >> this->bbt_erase_shift;
496 startblock &= bbtblocks - 1;
499 bbtblocks = mtd->size >> this->bbt_erase_shift;
502 /* Number of bits for each erase block in the bbt */
503 bits = td->options & NAND_BBT_NRBITS_MSK;
505 for (i = 0; i < chips; i++) {
506 /* Reset version information */
509 /* Scan the maximum number of blocks */
510 for (block = 0; block < td->maxblocks; block++) {
512 int actblock = startblock + dir * block;
513 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
515 /* Read first page */
516 scan_read_raw(mtd, buf, offs, mtd->writesize);
517 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
518 td->pages[i] = actblock << blocktopage;
519 if (td->options & NAND_BBT_VERSION) {
520 td->version[i] = buf[mtd->writesize + td->veroffs];
525 startblock += this->chipsize >> this->bbt_erase_shift;
527 /* Check, if we found a bbt for each requested chip */
528 for (i = 0; i < chips; i++) {
529 if (td->pages[i] == -1)
530 printk(KERN_WARNING "Bad block table not found for chip %d\n", i);
532 printk(KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i],
539 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
540 * @mtd: MTD device structure
541 * @buf: temporary buffer
542 * @td: descriptor for the bad block table
543 * @md: descriptor for the bad block table mirror
545 * Search and read the bad block table(s)
547 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
549 /* Search the primary table */
550 search_bbt(mtd, buf, td);
552 /* Search the mirror table */
554 search_bbt(mtd, buf, md);
556 /* Force result check */
561 * write_bbt - [GENERIC] (Re)write the bad block table
563 * @mtd: MTD device structure
564 * @buf: temporary buffer
565 * @td: descriptor for the bad block table
566 * @md: descriptor for the bad block table mirror
567 * @chipsel: selector for a specific chip, -1 for all
569 * (Re)write the bad block table
572 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
573 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
576 struct nand_chip *this = mtd->priv;
577 struct erase_info einfo;
578 int i, j, res, chip = 0;
579 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
580 int nrchips, bbtoffs, pageoffs, ooboffs;
582 uint8_t rcode = td->reserved_block_code;
583 size_t retlen, len = 0;
585 struct mtd_oob_ops ops;
587 ops.ooblen = mtd->oobsize;
590 ops.mode = MTD_OOB_PLACE;
594 /* Write bad block table per chip rather than per device ? */
595 if (td->options & NAND_BBT_PERCHIP) {
596 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
597 /* Full device write or specific chip ? */
599 nrchips = this->numchips;
601 nrchips = chipsel + 1;
605 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
609 /* Loop through the chips */
610 for (; chip < nrchips; chip++) {
612 /* There was already a version of the table, reuse the page
613 * This applies for absolute placement too, as we have the
614 * page nr. in td->pages.
616 if (td->pages[chip] != -1) {
617 page = td->pages[chip];
621 /* Automatic placement of the bad block table */
622 /* Search direction top -> down ? */
623 if (td->options & NAND_BBT_LASTBLOCK) {
624 startblock = numblocks * (chip + 1) - 1;
627 startblock = chip * numblocks;
631 for (i = 0; i < td->maxblocks; i++) {
632 int block = startblock + dir * i;
633 /* Check, if the block is bad */
634 switch ((this->bbt[block >> 2] >>
635 (2 * (block & 0x03))) & 0x03) {
641 (this->bbt_erase_shift - this->page_shift);
642 /* Check, if the block is used by the mirror table */
643 if (!md || md->pages[chip] != page)
646 printk(KERN_ERR "No space left to write bad block table\n");
650 /* Set up shift count and masks for the flash table */
651 bits = td->options & NAND_BBT_NRBITS_MSK;
654 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
657 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
660 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
663 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
666 default: return -EINVAL;
669 bbtoffs = chip * (numblocks >> 2);
671 to = ((loff_t) page) << this->page_shift;
673 /* Must we save the block contents ? */
674 if (td->options & NAND_BBT_SAVECONTENT) {
675 /* Make it block aligned */
676 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
677 len = 1 << this->bbt_erase_shift;
678 res = mtd->read(mtd, to, len, &retlen, buf);
681 printk(KERN_INFO "nand_bbt: Error "
682 "reading block for writing "
683 "the bad block table\n");
686 printk(KERN_WARNING "nand_bbt: ECC error "
687 "while reading block for writing "
688 "bad block table\n");
691 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
692 ops.oobbuf = &buf[len];
693 res = mtd->read_oob(mtd, to + mtd->writesize, &ops);
694 if (res < 0 || ops.oobretlen != ops.ooblen)
697 /* Calc the byte offset in the buffer */
698 pageoffs = page - (int)(to >> this->page_shift);
699 offs = pageoffs << this->page_shift;
700 /* Preset the bbt area with 0xff */
701 memset(&buf[offs], 0xff, (size_t) (numblocks >> sft));
702 ooboffs = len + (pageoffs * mtd->oobsize);
706 len = (size_t) (numblocks >> sft);
707 /* Make it page aligned ! */
708 len = (len + (mtd->writesize - 1)) &
709 ~(mtd->writesize - 1);
710 /* Preset the buffer with 0xff */
711 memset(buf, 0xff, len +
712 (len >> this->page_shift)* mtd->oobsize);
715 /* Pattern is located in oob area of first page */
716 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
719 if (td->options & NAND_BBT_VERSION)
720 buf[ooboffs + td->veroffs] = td->version[chip];
722 /* walk through the memory table */
723 for (i = 0; i < numblocks;) {
725 dat = this->bbt[bbtoffs + (i >> 2)];
726 for (j = 0; j < 4; j++, i++) {
727 int sftcnt = (i << (3 - sft)) & sftmsk;
728 /* Do not store the reserved bbt blocks ! */
729 buf[offs + (i >> sft)] &=
730 ~(msk[dat & 0x03] << sftcnt);
735 memset(&einfo, 0, sizeof(einfo));
738 einfo.len = 1 << this->bbt_erase_shift;
739 res = nand_erase_nand(mtd, &einfo, 1);
743 res = scan_write_bbt(mtd, to, len, buf, &buf[len]);
747 printk(KERN_DEBUG "Bad block table written to 0x%012llx, "
748 "version 0x%02X\n", (unsigned long long)to,
751 /* Mark it as used */
752 td->pages[chip] = page;
758 "nand_bbt: Error while writing bad block table %d\n", res);
763 * nand_memory_bbt - [GENERIC] create a memory based bad block table
764 * @mtd: MTD device structure
765 * @bd: descriptor for the good/bad block search pattern
767 * The function creates a memory based bbt by scanning the device
768 * for manufacturer / software marked good / bad blocks
770 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
772 struct nand_chip *this = mtd->priv;
774 bd->options &= ~NAND_BBT_SCANEMPTY;
775 return create_bbt(mtd, this->buffers->databuf, bd, -1);
779 * check_create - [GENERIC] create and write bbt(s) if necessary
780 * @mtd: MTD device structure
781 * @buf: temporary buffer
782 * @bd: descriptor for the good/bad block search pattern
784 * The function checks the results of the previous call to read_bbt
785 * and creates / updates the bbt(s) if necessary
786 * Creation is necessary if no bbt was found for the chip/device
787 * Update is necessary if one of the tables is missing or the
788 * version nr. of one table is less than the other
790 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
792 int i, chips, writeops, chipsel, res;
793 struct nand_chip *this = mtd->priv;
794 struct nand_bbt_descr *td = this->bbt_td;
795 struct nand_bbt_descr *md = this->bbt_md;
796 struct nand_bbt_descr *rd, *rd2;
798 /* Do we have a bbt per chip ? */
799 if (td->options & NAND_BBT_PERCHIP)
800 chips = this->numchips;
804 for (i = 0; i < chips; i++) {
808 /* Per chip or per device ? */
809 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
810 /* Mirrored table avilable ? */
812 if (td->pages[i] == -1 && md->pages[i] == -1) {
817 if (td->pages[i] == -1) {
819 td->version[i] = md->version[i];
824 if (md->pages[i] == -1) {
826 md->version[i] = td->version[i];
831 if (td->version[i] == md->version[i]) {
833 if (!(td->options & NAND_BBT_VERSION))
838 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
840 md->version[i] = td->version[i];
844 td->version[i] = md->version[i];
851 if (td->pages[i] == -1) {
859 /* Create the bad block table by scanning the device ? */
860 if (!(td->options & NAND_BBT_CREATE))
863 /* Create the table in memory by scanning the chip(s) */
864 create_bbt(mtd, buf, bd, chipsel);
870 /* read back first ? */
872 read_abs_bbt(mtd, buf, rd, chipsel);
873 /* If they weren't versioned, read both. */
875 read_abs_bbt(mtd, buf, rd2, chipsel);
877 /* Write the bad block table to the device ? */
878 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
879 res = write_bbt(mtd, buf, td, md, chipsel);
884 /* Write the mirror bad block table to the device ? */
885 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
886 res = write_bbt(mtd, buf, md, td, chipsel);
895 * mark_bbt_regions - [GENERIC] mark the bad block table regions
896 * @mtd: MTD device structure
897 * @td: bad block table descriptor
899 * The bad block table regions are marked as "bad" to prevent
900 * accidental erasures / writes. The regions are identified by
903 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
905 struct nand_chip *this = mtd->priv;
906 int i, j, chips, block, nrblocks, update;
907 uint8_t oldval, newval;
909 /* Do we have a bbt per chip ? */
910 if (td->options & NAND_BBT_PERCHIP) {
911 chips = this->numchips;
912 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
915 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
918 for (i = 0; i < chips; i++) {
919 if ((td->options & NAND_BBT_ABSPAGE) ||
920 !(td->options & NAND_BBT_WRITE)) {
921 if (td->pages[i] == -1)
923 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
925 oldval = this->bbt[(block >> 3)];
926 newval = oldval | (0x2 << (block & 0x06));
927 this->bbt[(block >> 3)] = newval;
928 if ((oldval != newval) && td->reserved_block_code)
929 nand_update_bbt(mtd, (loff_t)block <<
930 (this->bbt_erase_shift - 1));
934 if (td->options & NAND_BBT_LASTBLOCK)
935 block = ((i + 1) * nrblocks) - td->maxblocks;
937 block = i * nrblocks;
939 for (j = 0; j < td->maxblocks; j++) {
940 oldval = this->bbt[(block >> 3)];
941 newval = oldval | (0x2 << (block & 0x06));
942 this->bbt[(block >> 3)] = newval;
943 if (oldval != newval)
947 /* If we want reserved blocks to be recorded to flash, and some
948 new ones have been marked, then we need to update the stored
949 bbts. This should only happen once. */
950 if (update && td->reserved_block_code)
951 nand_update_bbt(mtd, (loff_t)(block - 2) <<
952 (this->bbt_erase_shift - 1));
957 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
958 * @mtd: MTD device structure
959 * @bd: descriptor for the good/bad block search pattern
961 * The function checks, if a bad block table(s) is/are already
962 * available. If not it scans the device for manufacturer
963 * marked good / bad blocks and writes the bad block table(s) to
964 * the selected place.
966 * The bad block table memory is allocated here. It must be freed
967 * by calling the nand_free_bbt function.
970 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
972 struct nand_chip *this = mtd->priv;
975 struct nand_bbt_descr *td = this->bbt_td;
976 struct nand_bbt_descr *md = this->bbt_md;
978 len = mtd->size >> (this->bbt_erase_shift + 2);
979 /* Allocate memory (2bit per block) and clear the memory bad block table */
980 this->bbt = kzalloc(len, GFP_KERNEL);
982 printk(KERN_ERR "nand_scan_bbt: Out of memory\n");
986 /* If no primary table decriptor is given, scan the device
987 * to build a memory based bad block table
990 if ((res = nand_memory_bbt(mtd, bd))) {
991 printk(KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
998 /* Allocate a temporary buffer for one eraseblock incl. oob */
999 len = (1 << this->bbt_erase_shift);
1000 len += (len >> this->page_shift) * mtd->oobsize;
1003 printk(KERN_ERR "nand_bbt: Out of memory\n");
1009 /* Is the bbt at a given page ? */
1010 if (td->options & NAND_BBT_ABSPAGE) {
1011 res = read_abs_bbts(mtd, buf, td, md);
1013 /* Search the bad block table using a pattern in oob */
1014 res = search_read_bbts(mtd, buf, td, md);
1018 res = check_create(mtd, buf, bd);
1020 /* Prevent the bbt regions from erasing / writing */
1021 mark_bbt_region(mtd, td);
1023 mark_bbt_region(mtd, md);
1030 * nand_update_bbt - [NAND Interface] update bad block table(s)
1031 * @mtd: MTD device structure
1032 * @offs: the offset of the newly marked block
1034 * The function updates the bad block table(s)
1036 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1038 struct nand_chip *this = mtd->priv;
1039 int len, res = 0, writeops = 0;
1042 struct nand_bbt_descr *td = this->bbt_td;
1043 struct nand_bbt_descr *md = this->bbt_md;
1045 if (!this->bbt || !td)
1048 /* Allocate a temporary buffer for one eraseblock incl. oob */
1049 len = (1 << this->bbt_erase_shift);
1050 len += (len >> this->page_shift) * mtd->oobsize;
1051 buf = kmalloc(len, GFP_KERNEL);
1053 printk(KERN_ERR "nand_update_bbt: Out of memory\n");
1057 writeops = md != NULL ? 0x03 : 0x01;
1059 /* Do we have a bbt per chip ? */
1060 if (td->options & NAND_BBT_PERCHIP) {
1061 chip = (int)(offs >> this->chip_shift);
1068 td->version[chip]++;
1070 md->version[chip]++;
1072 /* Write the bad block table to the device ? */
1073 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1074 res = write_bbt(mtd, buf, td, md, chipsel);
1078 /* Write the mirror bad block table to the device ? */
1079 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1080 res = write_bbt(mtd, buf, md, td, chipsel);
1088 /* Define some generic bad / good block scan pattern which are used
1089 * while scanning a device for factory marked good / bad blocks. */
1090 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1092 static struct nand_bbt_descr smallpage_memorybased = {
1093 .options = NAND_BBT_SCAN2NDPAGE,
1096 .pattern = scan_ff_pattern
1099 static struct nand_bbt_descr largepage_memorybased = {
1103 .pattern = scan_ff_pattern
1106 static struct nand_bbt_descr smallpage_flashbased = {
1107 .options = NAND_BBT_SCAN2NDPAGE,
1110 .pattern = scan_ff_pattern
1113 static struct nand_bbt_descr largepage_flashbased = {
1114 .options = NAND_BBT_SCAN2NDPAGE,
1117 .pattern = scan_ff_pattern
1120 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1122 static struct nand_bbt_descr agand_flashbased = {
1123 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1126 .pattern = scan_agand_pattern
1129 /* Generic flash bbt decriptors
1131 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1132 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1134 static struct nand_bbt_descr bbt_main_descr = {
1135 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1136 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1141 .pattern = bbt_pattern
1144 static struct nand_bbt_descr bbt_mirror_descr = {
1145 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1146 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1151 .pattern = mirror_pattern
1155 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1156 * @mtd: MTD device structure
1158 * This function selects the default bad block table
1159 * support for the device and calls the nand_scan_bbt function
1162 int nand_default_bbt(struct mtd_info *mtd)
1164 struct nand_chip *this = mtd->priv;
1166 /* Default for AG-AND. We must use a flash based
1167 * bad block table as the devices have factory marked
1168 * _good_ blocks. Erasing those blocks leads to loss
1169 * of the good / bad information, so we _must_ store
1170 * this information in a good / bad table during
1173 if (this->options & NAND_IS_AND) {
1174 /* Use the default pattern descriptors */
1175 if (!this->bbt_td) {
1176 this->bbt_td = &bbt_main_descr;
1177 this->bbt_md = &bbt_mirror_descr;
1179 this->options |= NAND_USE_FLASH_BBT;
1180 return nand_scan_bbt(mtd, &agand_flashbased);
1183 /* Is a flash based bad block table requested ? */
1184 if (this->options & NAND_USE_FLASH_BBT) {
1185 /* Use the default pattern descriptors */
1186 if (!this->bbt_td) {
1187 this->bbt_td = &bbt_main_descr;
1188 this->bbt_md = &bbt_mirror_descr;
1190 if (!this->badblock_pattern) {
1191 this->badblock_pattern = (mtd->writesize > 512) ? &largepage_flashbased : &smallpage_flashbased;
1194 this->bbt_td = NULL;
1195 this->bbt_md = NULL;
1196 if (!this->badblock_pattern) {
1197 this->badblock_pattern = (mtd->writesize > 512) ?
1198 &largepage_memorybased : &smallpage_memorybased;
1201 return nand_scan_bbt(mtd, this->badblock_pattern);
1205 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1206 * @mtd: MTD device structure
1207 * @offs: offset in the device
1208 * @allowbbt: allow access to bad block table region
1211 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1213 struct nand_chip *this = mtd->priv;
1217 /* Get block number * 2 */
1218 block = (int)(offs >> (this->bbt_erase_shift - 1));
1219 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1221 MTDDEBUG (MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: "
1222 "(block %d) 0x%02x\n", (unsigned int)offs, res, block >> 1);
1230 return allowbbt ? 0 : 1;
1235 /* XXX U-BOOT XXX */
1237 EXPORT_SYMBOL(nand_scan_bbt);
1238 EXPORT_SYMBOL(nand_default_bbt);