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 * $Id: nand_bbt.c,v 1.36 2005/11/07 11:14:30 gleixner Exp $
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
17 * When nand_scan_bbt is called, then it tries to find the bad block table
18 * depending on the options in the bbt descriptor(s). If a bbt is found
19 * then the contents are read and the memory based bbt is created. If a
20 * mirrored bbt is selected then the mirror is searched too and the
21 * versions are compared. If the mirror has a greater version number
22 * than the mirror bbt is used to build the memory based bbt.
23 * If the tables are not versioned, then we "or" the bad block information.
24 * If one of the bbt's is out of date or does not exist it is (re)created.
25 * If no bbt exists at all then the device is scanned for factory marked
26 * good / bad blocks and the bad block tables are created.
28 * For manufacturer created bbts like the one found on M-SYS DOC devices
29 * the bbt is searched and read but never created
31 * The autogenerated bad block table is located in the last good blocks
32 * of the device. The table is mirrored, so it can be updated eventually.
33 * The table is marked in the oob area with an ident pattern and a version
34 * number which indicates which of both tables is more up to date.
36 * The table uses 2 bits per block
38 * 00b: block is factory marked bad
39 * 01b, 10b: block is marked bad due to wear
41 * The memory bad block table uses the following scheme:
43 * 01b: block is marked bad due to wear
44 * 10b: block is reserved (to protect the bbt area)
45 * 11b: block is factory marked bad
47 * Multichip devices like DOC store the bad block info per floor.
49 * Following assumptions are made:
50 * - bbts start at a page boundary, if autolocated on a block boundary
51 * - the space necessary for a bbt in FLASH does not exceed a block boundary
55 #include <linux/slab.h>
56 #include <linux/types.h>
57 #include <linux/mtd/mtd.h>
58 #include <linux/mtd/nand.h>
59 #include <linux/mtd/nand_ecc.h>
60 #include <linux/mtd/compatmac.h>
61 #include <linux/bitops.h>
62 #include <linux/delay.h>
63 #include <linux/vmalloc.h>
66 * check_pattern - [GENERIC] check if a pattern is in the buffer
67 * @buf: the buffer to search
68 * @len: the length of buffer to search
69 * @paglen: the pagelength
70 * @td: search pattern descriptor
72 * Check for a pattern at the given place. Used to search bad block
73 * tables and good / bad block identifiers.
74 * If the SCAN_EMPTY option is set then check, if all bytes except the
75 * pattern area contain 0xff
78 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
83 end = paglen + td->offs;
84 if (td->options & NAND_BBT_SCANEMPTY) {
85 for (i = 0; i < end; i++) {
92 /* Compare the pattern */
93 for (i = 0; i < td->len; i++) {
94 if (p[i] != td->pattern[i])
98 if (td->options & NAND_BBT_SCANEMPTY) {
101 for (i = end; i < len; i++) {
110 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
111 * @buf: the buffer to search
112 * @td: search pattern descriptor
114 * Check for a pattern at the given place. Used to search bad block
115 * tables and good / bad block identifiers. Same as check_pattern, but
116 * no optional empty check
119 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
124 /* Compare the pattern */
125 for (i = 0; i < td->len; i++) {
126 if (p[td->offs + i] != td->pattern[i])
133 * read_bbt - [GENERIC] Read the bad block table starting from page
134 * @mtd: MTD device structure
135 * @buf: temporary buffer
136 * @page: the starting page
137 * @num: the number of bbt descriptors to read
138 * @bits: number of bits per block
139 * @offs: offset in the memory table
140 * @reserved_block_code: Pattern to identify reserved blocks
142 * Read the bad block table starting from page.
145 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
146 int bits, int offs, int reserved_block_code)
148 int res, i, j, act = 0;
149 struct nand_chip *this = mtd->priv;
150 size_t retlen, len, totlen;
152 uint8_t msk = (uint8_t) ((1 << bits) - 1);
154 totlen = (num * bits) >> 3;
155 from = ((loff_t) page) << this->page_shift;
158 len = min(totlen, (size_t) (1 << this->bbt_erase_shift));
159 res = mtd->read(mtd, from, len, &retlen, buf);
162 printk(KERN_INFO "nand_bbt: Error reading bad block table\n");
165 printk(KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
169 for (i = 0; i < len; i++) {
170 uint8_t dat = buf[i];
171 for (j = 0; j < 8; j += bits, act += 2) {
172 uint8_t tmp = (dat >> j) & msk;
175 if (reserved_block_code && (tmp == reserved_block_code)) {
176 printk(KERN_DEBUG "nand_read_bbt: Reserved block at 0x%08x\n",
177 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
178 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
181 /* Leave it for now, if its matured we can move this
182 * message to MTD_DEBUG_LEVEL0 */
183 printk(KERN_DEBUG "nand_read_bbt: Bad block at 0x%08x\n",
184 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
185 /* Factory marked bad or worn out ? */
187 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
189 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
199 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
200 * @mtd: MTD device structure
201 * @buf: temporary buffer
202 * @td: descriptor for the bad block table
203 * @chip: read the table for a specific chip, -1 read all chips.
204 * Applies only if NAND_BBT_PERCHIP option is set
206 * Read the bad block table for all chips starting at a given page
207 * We assume that the bbt bits are in consecutive order.
209 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
211 struct nand_chip *this = mtd->priv;
215 bits = td->options & NAND_BBT_NRBITS_MSK;
216 if (td->options & NAND_BBT_PERCHIP) {
218 for (i = 0; i < this->numchips; i++) {
219 if (chip == -1 || chip == i)
220 res = read_bbt (mtd, buf, td->pages[i], this->chipsize >> this->bbt_erase_shift, bits, offs, td->reserved_block_code);
223 offs += this->chipsize >> (this->bbt_erase_shift + 2);
226 res = read_bbt (mtd, buf, td->pages[0], mtd->size >> this->bbt_erase_shift, bits, 0, td->reserved_block_code);
234 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
235 * @mtd: MTD device structure
236 * @buf: temporary buffer
237 * @td: descriptor for the bad block table
238 * @md: descriptor for the bad block table mirror
240 * Read the bad block table(s) for all chips starting at a given page
241 * We assume that the bbt bits are in consecutive order.
244 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
246 struct nand_chip *this = mtd->priv;
248 /* Read the primary version, if available */
249 if (td->options & NAND_BBT_VERSION) {
250 nand_read_raw(mtd, buf, td->pages[0] << this->page_shift, mtd->writesize, mtd->oobsize);
251 td->version[0] = buf[mtd->writesize + td->veroffs];
252 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n", td->pages[0], td->version[0]);
255 /* Read the mirror version, if available */
256 if (md && (md->options & NAND_BBT_VERSION)) {
257 nand_read_raw(mtd, buf, md->pages[0] << this->page_shift, mtd->writesize, mtd->oobsize);
258 md->version[0] = buf[mtd->writesize + md->veroffs];
259 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n", md->pages[0], md->version[0]);
266 * create_bbt - [GENERIC] Create a bad block table by scanning the device
267 * @mtd: MTD device structure
268 * @buf: temporary buffer
269 * @bd: descriptor for the good/bad block search pattern
270 * @chip: create the table for a specific chip, -1 read all chips.
271 * Applies only if NAND_BBT_PERCHIP option is set
273 * Create a bad block table by scanning the device
274 * for the given good/bad block identify pattern
276 static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
278 struct nand_chip *this = mtd->priv;
279 int i, j, numblocks, len, scanlen;
282 size_t readlen, ooblen;
284 printk(KERN_INFO "Scanning device for bad blocks\n");
286 if (bd->options & NAND_BBT_SCANALLPAGES)
287 len = 1 << (this->bbt_erase_shift - this->page_shift);
289 if (bd->options & NAND_BBT_SCAN2NDPAGE)
295 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
296 /* We need only read few bytes from the OOB area */
297 scanlen = ooblen = 0;
300 /* Full page content should be read */
301 scanlen = mtd->writesize + mtd->oobsize;
302 readlen = len * mtd->writesize;
303 ooblen = len * mtd->oobsize;
307 /* Note that numblocks is 2 * (real numblocks) here, see i+=2 below as it
308 * makes shifting and masking less painful */
309 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
313 if (chip >= this->numchips) {
314 printk(KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
315 chip + 1, this->numchips);
318 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
319 startblock = chip * numblocks;
320 numblocks += startblock;
321 from = startblock << (this->bbt_erase_shift - 1);
324 for (i = startblock; i < numblocks;) {
327 if (bd->options & NAND_BBT_SCANEMPTY)
328 if ((ret = nand_read_raw(mtd, buf, from, readlen, ooblen)))
331 for (j = 0; j < len; j++) {
332 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
335 /* Read the full oob until read_oob is fixed to
336 * handle single byte reads for 16 bit buswidth */
337 ret = mtd->read_oob(mtd, from + j * mtd->writesize, mtd->oobsize, &retlen, buf);
341 if (check_short_pattern(buf, bd)) {
342 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
343 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
344 i >> 1, (unsigned int)from);
348 if (check_pattern(&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
349 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
350 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
351 i >> 1, (unsigned int)from);
357 from += (1 << this->bbt_erase_shift);
363 * search_bbt - [GENERIC] scan the device for a specific bad block table
364 * @mtd: MTD device structure
365 * @buf: temporary buffer
366 * @td: descriptor for the bad block table
368 * Read the bad block table by searching for a given ident pattern.
369 * Search is preformed either from the beginning up or from the end of
370 * the device downwards. The search starts always at the start of a
372 * If the option NAND_BBT_PERCHIP is given, each chip is searched
373 * for a bbt, which contains the bad block information of this chip.
374 * This is necessary to provide support for certain DOC devices.
376 * The bbt ident pattern resides in the oob area of the first page
379 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
381 struct nand_chip *this = mtd->priv;
383 int bits, startblock, block, dir;
384 int scanlen = mtd->writesize + mtd->oobsize;
387 /* Search direction top -> down ? */
388 if (td->options & NAND_BBT_LASTBLOCK) {
389 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
396 /* Do we have a bbt per chip ? */
397 if (td->options & NAND_BBT_PERCHIP) {
398 chips = this->numchips;
399 bbtblocks = this->chipsize >> this->bbt_erase_shift;
400 startblock &= bbtblocks - 1;
403 bbtblocks = mtd->size >> this->bbt_erase_shift;
406 /* Number of bits for each erase block in the bbt */
407 bits = td->options & NAND_BBT_NRBITS_MSK;
409 for (i = 0; i < chips; i++) {
410 /* Reset version information */
413 /* Scan the maximum number of blocks */
414 for (block = 0; block < td->maxblocks; block++) {
415 int actblock = startblock + dir * block;
416 /* Read first page */
417 nand_read_raw(mtd, buf, actblock << this->bbt_erase_shift, mtd->writesize, mtd->oobsize);
418 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
419 td->pages[i] = actblock << (this->bbt_erase_shift - this->page_shift);
420 if (td->options & NAND_BBT_VERSION) {
421 td->version[i] = buf[mtd->writesize + td->veroffs];
426 startblock += this->chipsize >> this->bbt_erase_shift;
428 /* Check, if we found a bbt for each requested chip */
429 for (i = 0; i < chips; i++) {
430 if (td->pages[i] == -1)
431 printk(KERN_WARNING "Bad block table not found for chip %d\n", i);
433 printk(KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i],
440 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
441 * @mtd: MTD device structure
442 * @buf: temporary buffer
443 * @td: descriptor for the bad block table
444 * @md: descriptor for the bad block table mirror
446 * Search and read the bad block table(s)
448 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
450 /* Search the primary table */
451 search_bbt(mtd, buf, td);
453 /* Search the mirror table */
455 search_bbt(mtd, buf, md);
457 /* Force result check */
462 * write_bbt - [GENERIC] (Re)write the bad block table
464 * @mtd: MTD device structure
465 * @buf: temporary buffer
466 * @td: descriptor for the bad block table
467 * @md: descriptor for the bad block table mirror
468 * @chipsel: selector for a specific chip, -1 for all
470 * (Re)write the bad block table
473 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
474 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
477 struct nand_chip *this = mtd->priv;
478 struct erase_info einfo;
479 int i, j, res, chip = 0;
480 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
481 int nrchips, bbtoffs, pageoffs, ooboffs;
483 uint8_t rcode = td->reserved_block_code;
484 size_t retlen, len = 0, ooblen;
489 /* Write bad block table per chip rather than per device ? */
490 if (td->options & NAND_BBT_PERCHIP) {
491 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
492 /* Full device write or specific chip ? */
494 nrchips = this->numchips;
496 nrchips = chipsel + 1;
500 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
504 /* Loop through the chips */
505 for (; chip < nrchips; chip++) {
507 /* There was already a version of the table, reuse the page
508 * This applies for absolute placement too, as we have the
509 * page nr. in td->pages.
511 if (td->pages[chip] != -1) {
512 page = td->pages[chip];
516 /* Automatic placement of the bad block table */
517 /* Search direction top -> down ? */
518 if (td->options & NAND_BBT_LASTBLOCK) {
519 startblock = numblocks * (chip + 1) - 1;
522 startblock = chip * numblocks;
526 for (i = 0; i < td->maxblocks; i++) {
527 int block = startblock + dir * i;
528 /* Check, if the block is bad */
529 switch ((this->bbt[block >> 2] >>
530 (2 * (block & 0x03))) & 0x03) {
536 (this->bbt_erase_shift - this->page_shift);
537 /* Check, if the block is used by the mirror table */
538 if (!md || md->pages[chip] != page)
541 printk(KERN_ERR "No space left to write bad block table\n");
545 /* Set up shift count and masks for the flash table */
546 bits = td->options & NAND_BBT_NRBITS_MSK;
549 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
552 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
555 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
558 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
561 default: return -EINVAL;
564 bbtoffs = chip * (numblocks >> 2);
566 to = ((loff_t) page) << this->page_shift;
568 /* Must we save the block contents ? */
569 if (td->options & NAND_BBT_SAVECONTENT) {
570 /* Make it block aligned */
571 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
572 len = 1 << this->bbt_erase_shift;
573 res = mtd->read(mtd, to, len, &retlen, buf);
576 printk(KERN_INFO "nand_bbt: Error "
577 "reading block for writing "
578 "the bad block table\n");
581 printk(KERN_WARNING "nand_bbt: ECC error "
582 "while reading block for writing "
583 "bad block table\n");
586 ooblen = (len >> this->page_shift) * mtd->oobsize;
587 res = mtd->read_oob(mtd, to + mtd->writesize, ooblen,
589 if (res < 0 || retlen != ooblen)
592 /* Calc the byte offset in the buffer */
593 pageoffs = page - (int)(to >> this->page_shift);
594 offs = pageoffs << this->page_shift;
595 /* Preset the bbt area with 0xff */
596 memset(&buf[offs], 0xff, (size_t) (numblocks >> sft));
597 ooboffs = len + (pageoffs * mtd->oobsize);
601 len = (size_t) (numblocks >> sft);
602 /* Make it page aligned ! */
603 len = (len + (mtd->writesize - 1)) &
604 ~(mtd->writesize - 1);
605 /* Preset the buffer with 0xff */
606 memset(buf, 0xff, len +
607 (len >> this->page_shift)* mtd->oobsize);
610 /* Pattern is located in oob area of first page */
611 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
614 if (td->options & NAND_BBT_VERSION)
615 buf[ooboffs + td->veroffs] = td->version[chip];
617 /* walk through the memory table */
618 for (i = 0; i < numblocks;) {
620 dat = this->bbt[bbtoffs + (i >> 2)];
621 for (j = 0; j < 4; j++, i++) {
622 int sftcnt = (i << (3 - sft)) & sftmsk;
623 /* Do not store the reserved bbt blocks ! */
624 buf[offs + (i >> sft)] &=
625 ~(msk[dat & 0x03] << sftcnt);
630 memset(&einfo, 0, sizeof(einfo));
632 einfo.addr = (unsigned long)to;
633 einfo.len = 1 << this->bbt_erase_shift;
634 res = nand_erase_nand(mtd, &einfo, 1);
638 res = nand_write_raw(mtd, to, len, &retlen, buf, &buf[len]);
642 printk(KERN_DEBUG "Bad block table written to 0x%08x, version "
643 "0x%02X\n", (unsigned int)to, td->version[chip]);
645 /* Mark it as used */
646 td->pages[chip] = page;
652 "nand_bbt: Error while writing bad block table %d\n", res);
657 * nand_memory_bbt - [GENERIC] create a memory based bad block table
658 * @mtd: MTD device structure
659 * @bd: descriptor for the good/bad block search pattern
661 * The function creates a memory based bbt by scanning the device
662 * for manufacturer / software marked good / bad blocks
664 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
666 struct nand_chip *this = mtd->priv;
668 bd->options &= ~NAND_BBT_SCANEMPTY;
669 return create_bbt(mtd, this->buffers.databuf, bd, -1);
673 * check_create - [GENERIC] create and write bbt(s) if necessary
674 * @mtd: MTD device structure
675 * @buf: temporary buffer
676 * @bd: descriptor for the good/bad block search pattern
678 * The function checks the results of the previous call to read_bbt
679 * and creates / updates the bbt(s) if necessary
680 * Creation is necessary if no bbt was found for the chip/device
681 * Update is necessary if one of the tables is missing or the
682 * version nr. of one table is less than the other
684 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
686 int i, chips, writeops, chipsel, res;
687 struct nand_chip *this = mtd->priv;
688 struct nand_bbt_descr *td = this->bbt_td;
689 struct nand_bbt_descr *md = this->bbt_md;
690 struct nand_bbt_descr *rd, *rd2;
692 /* Do we have a bbt per chip ? */
693 if (td->options & NAND_BBT_PERCHIP)
694 chips = this->numchips;
698 for (i = 0; i < chips; i++) {
702 /* Per chip or per device ? */
703 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
704 /* Mirrored table avilable ? */
706 if (td->pages[i] == -1 && md->pages[i] == -1) {
711 if (td->pages[i] == -1) {
713 td->version[i] = md->version[i];
718 if (md->pages[i] == -1) {
720 md->version[i] = td->version[i];
725 if (td->version[i] == md->version[i]) {
727 if (!(td->options & NAND_BBT_VERSION))
732 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
734 md->version[i] = td->version[i];
738 td->version[i] = md->version[i];
745 if (td->pages[i] == -1) {
753 /* Create the bad block table by scanning the device ? */
754 if (!(td->options & NAND_BBT_CREATE))
757 /* Create the table in memory by scanning the chip(s) */
758 create_bbt(mtd, buf, bd, chipsel);
764 /* read back first ? */
766 read_abs_bbt(mtd, buf, rd, chipsel);
767 /* If they weren't versioned, read both. */
769 read_abs_bbt(mtd, buf, rd2, chipsel);
771 /* Write the bad block table to the device ? */
772 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
773 res = write_bbt(mtd, buf, td, md, chipsel);
778 /* Write the mirror bad block table to the device ? */
779 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
780 res = write_bbt(mtd, buf, md, td, chipsel);
789 * mark_bbt_regions - [GENERIC] mark the bad block table regions
790 * @mtd: MTD device structure
791 * @td: bad block table descriptor
793 * The bad block table regions are marked as "bad" to prevent
794 * accidental erasures / writes. The regions are identified by
797 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
799 struct nand_chip *this = mtd->priv;
800 int i, j, chips, block, nrblocks, update;
801 uint8_t oldval, newval;
803 /* Do we have a bbt per chip ? */
804 if (td->options & NAND_BBT_PERCHIP) {
805 chips = this->numchips;
806 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
809 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
812 for (i = 0; i < chips; i++) {
813 if ((td->options & NAND_BBT_ABSPAGE) ||
814 !(td->options & NAND_BBT_WRITE)) {
815 if (td->pages[i] == -1)
817 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
819 oldval = this->bbt[(block >> 3)];
820 newval = oldval | (0x2 << (block & 0x06));
821 this->bbt[(block >> 3)] = newval;
822 if ((oldval != newval) && td->reserved_block_code)
823 nand_update_bbt(mtd, block << (this->bbt_erase_shift - 1));
827 if (td->options & NAND_BBT_LASTBLOCK)
828 block = ((i + 1) * nrblocks) - td->maxblocks;
830 block = i * nrblocks;
832 for (j = 0; j < td->maxblocks; j++) {
833 oldval = this->bbt[(block >> 3)];
834 newval = oldval | (0x2 << (block & 0x06));
835 this->bbt[(block >> 3)] = newval;
836 if (oldval != newval)
840 /* If we want reserved blocks to be recorded to flash, and some
841 new ones have been marked, then we need to update the stored
842 bbts. This should only happen once. */
843 if (update && td->reserved_block_code)
844 nand_update_bbt(mtd, (block - 2) << (this->bbt_erase_shift - 1));
849 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
850 * @mtd: MTD device structure
851 * @bd: descriptor for the good/bad block search pattern
853 * The function checks, if a bad block table(s) is/are already
854 * available. If not it scans the device for manufacturer
855 * marked good / bad blocks and writes the bad block table(s) to
856 * the selected place.
858 * The bad block table memory is allocated here. It must be freed
859 * by calling the nand_free_bbt function.
862 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
864 struct nand_chip *this = mtd->priv;
867 struct nand_bbt_descr *td = this->bbt_td;
868 struct nand_bbt_descr *md = this->bbt_md;
870 len = mtd->size >> (this->bbt_erase_shift + 2);
871 /* Allocate memory (2bit per block) */
872 this->bbt = kmalloc(len, GFP_KERNEL);
874 printk(KERN_ERR "nand_scan_bbt: Out of memory\n");
877 /* Clear the memory bad block table */
878 memset(this->bbt, 0x00, len);
880 /* If no primary table decriptor is given, scan the device
881 * to build a memory based bad block table
884 if ((res = nand_memory_bbt(mtd, bd))) {
885 printk(KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
892 /* Allocate a temporary buffer for one eraseblock incl. oob */
893 len = (1 << this->bbt_erase_shift);
894 len += (len >> this->page_shift) * mtd->oobsize;
897 printk(KERN_ERR "nand_bbt: Out of memory\n");
903 /* Is the bbt at a given page ? */
904 if (td->options & NAND_BBT_ABSPAGE) {
905 res = read_abs_bbts(mtd, buf, td, md);
907 /* Search the bad block table using a pattern in oob */
908 res = search_read_bbts(mtd, buf, td, md);
912 res = check_create(mtd, buf, bd);
914 /* Prevent the bbt regions from erasing / writing */
915 mark_bbt_region(mtd, td);
917 mark_bbt_region(mtd, md);
924 * nand_update_bbt - [NAND Interface] update bad block table(s)
925 * @mtd: MTD device structure
926 * @offs: the offset of the newly marked block
928 * The function updates the bad block table(s)
930 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
932 struct nand_chip *this = mtd->priv;
933 int len, res = 0, writeops = 0;
936 struct nand_bbt_descr *td = this->bbt_td;
937 struct nand_bbt_descr *md = this->bbt_md;
939 if (!this->bbt || !td)
942 len = mtd->size >> (this->bbt_erase_shift + 2);
943 /* Allocate a temporary buffer for one eraseblock incl. oob */
944 len = (1 << this->bbt_erase_shift);
945 len += (len >> this->page_shift) * mtd->oobsize;
946 buf = kmalloc(len, GFP_KERNEL);
948 printk(KERN_ERR "nand_update_bbt: Out of memory\n");
952 writeops = md != NULL ? 0x03 : 0x01;
954 /* Do we have a bbt per chip ? */
955 if (td->options & NAND_BBT_PERCHIP) {
956 chip = (int)(offs >> this->chip_shift);
967 /* Write the bad block table to the device ? */
968 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
969 res = write_bbt(mtd, buf, td, md, chipsel);
973 /* Write the mirror bad block table to the device ? */
974 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
975 res = write_bbt(mtd, buf, md, td, chipsel);
983 /* Define some generic bad / good block scan pattern which are used
984 * while scanning a device for factory marked good / bad blocks. */
985 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
987 static struct nand_bbt_descr smallpage_memorybased = {
988 .options = NAND_BBT_SCAN2NDPAGE,
991 .pattern = scan_ff_pattern
994 static struct nand_bbt_descr largepage_memorybased = {
998 .pattern = scan_ff_pattern
1001 static struct nand_bbt_descr smallpage_flashbased = {
1002 .options = NAND_BBT_SCAN2NDPAGE,
1005 .pattern = scan_ff_pattern
1008 static struct nand_bbt_descr largepage_flashbased = {
1009 .options = NAND_BBT_SCAN2NDPAGE,
1012 .pattern = scan_ff_pattern
1015 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1017 static struct nand_bbt_descr agand_flashbased = {
1018 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1021 .pattern = scan_agand_pattern
1024 /* Generic flash bbt decriptors
1026 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1027 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1029 static struct nand_bbt_descr bbt_main_descr = {
1030 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1031 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1036 .pattern = bbt_pattern
1039 static struct nand_bbt_descr bbt_mirror_descr = {
1040 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1041 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1046 .pattern = mirror_pattern
1050 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1051 * @mtd: MTD device structure
1053 * This function selects the default bad block table
1054 * support for the device and calls the nand_scan_bbt function
1057 int nand_default_bbt(struct mtd_info *mtd)
1059 struct nand_chip *this = mtd->priv;
1061 /* Default for AG-AND. We must use a flash based
1062 * bad block table as the devices have factory marked
1063 * _good_ blocks. Erasing those blocks leads to loss
1064 * of the good / bad information, so we _must_ store
1065 * this information in a good / bad table during
1068 if (this->options & NAND_IS_AND) {
1069 /* Use the default pattern descriptors */
1070 if (!this->bbt_td) {
1071 this->bbt_td = &bbt_main_descr;
1072 this->bbt_md = &bbt_mirror_descr;
1074 this->options |= NAND_USE_FLASH_BBT;
1075 return nand_scan_bbt(mtd, &agand_flashbased);
1078 /* Is a flash based bad block table requested ? */
1079 if (this->options & NAND_USE_FLASH_BBT) {
1080 /* Use the default pattern descriptors */
1081 if (!this->bbt_td) {
1082 this->bbt_td = &bbt_main_descr;
1083 this->bbt_md = &bbt_mirror_descr;
1085 if (!this->badblock_pattern) {
1086 this->badblock_pattern = (mtd->writesize > 512) ? &largepage_flashbased : &smallpage_flashbased;
1089 this->bbt_td = NULL;
1090 this->bbt_md = NULL;
1091 if (!this->badblock_pattern) {
1092 this->badblock_pattern = (mtd->writesize > 512) ?
1093 &largepage_memorybased : &smallpage_memorybased;
1096 return nand_scan_bbt(mtd, this->badblock_pattern);
1100 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1101 * @mtd: MTD device structure
1102 * @offs: offset in the device
1103 * @allowbbt: allow access to bad block table region
1106 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1108 struct nand_chip *this = mtd->priv;
1112 /* Get block number * 2 */
1113 block = (int)(offs >> (this->bbt_erase_shift - 1));
1114 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1116 DEBUG(MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1117 (unsigned int)offs, block >> 1, res);
1125 return allowbbt ? 0 : 1;
1130 EXPORT_SYMBOL(nand_scan_bbt);
1131 EXPORT_SYMBOL(nand_default_bbt);