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22 * If one of the bbt's is out of date or does not exist it is (re)created.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%08x\n",
186 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
187 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
188 mtd->ecc_stats.bbtblocks++;
191 /* Leave it for now, if its matured we can move this
192 * message to MTD_DEBUG_LEVEL0 */
193 printk(KERN_DEBUG "nand_read_bbt: Bad block at 0x%08x\n",
194 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
195 /* Factory marked bad or worn out ? */
197 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
199 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
200 mtd->ecc_stats.badblocks++;
210 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
211 * @mtd: MTD device structure
212 * @buf: temporary buffer
213 * @td: descriptor for the bad block table
214 * @chip: read the table for a specific chip, -1 read all chips.
215 * Applies only if NAND_BBT_PERCHIP option is set
217 * Read the bad block table for all chips starting at a given page
218 * We assume that the bbt bits are in consecutive order.
220 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
222 struct nand_chip *this = mtd->priv;
226 bits = td->options & NAND_BBT_NRBITS_MSK;
227 if (td->options & NAND_BBT_PERCHIP) {
229 for (i = 0; i < this->numchips; i++) {
230 if (chip == -1 || chip == i)
231 res = read_bbt (mtd, buf, td->pages[i], this->chipsize >> this->bbt_erase_shift, bits, offs, td->reserved_block_code);
234 offs += this->chipsize >> (this->bbt_erase_shift + 2);
237 res = read_bbt (mtd, buf, td->pages[0], mtd->size >> this->bbt_erase_shift, bits, 0, td->reserved_block_code);
245 * Scan read raw data from flash
247 static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
250 struct mtd_oob_ops ops;
252 ops.mode = MTD_OOB_RAW;
254 ops.ooblen = mtd->oobsize;
259 return mtd->read_oob(mtd, offs, &ops);
263 * Scan write data with oob to flash
265 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
266 uint8_t *buf, uint8_t *oob)
268 struct mtd_oob_ops ops;
270 ops.mode = MTD_OOB_PLACE;
272 ops.ooblen = mtd->oobsize;
277 return mtd->write_oob(mtd, offs, &ops);
281 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
282 * @mtd: MTD device structure
283 * @buf: temporary buffer
284 * @td: descriptor for the bad block table
285 * @md: descriptor for the bad block table mirror
287 * Read the bad block table(s) for all chips starting at a given page
288 * We assume that the bbt bits are in consecutive order.
291 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
292 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
294 struct nand_chip *this = mtd->priv;
296 /* Read the primary version, if available */
297 if (td->options & NAND_BBT_VERSION) {
298 scan_read_raw(mtd, buf, td->pages[0] << this->page_shift,
300 td->version[0] = buf[mtd->writesize + td->veroffs];
301 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
302 td->pages[0], td->version[0]);
305 /* Read the mirror version, if available */
306 if (md && (md->options & NAND_BBT_VERSION)) {
307 scan_read_raw(mtd, buf, md->pages[0] << this->page_shift,
309 md->version[0] = buf[mtd->writesize + md->veroffs];
310 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
311 md->pages[0], md->version[0]);
317 * Scan a given block full
319 static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
320 loff_t offs, uint8_t *buf, size_t readlen,
321 int scanlen, int len)
325 ret = scan_read_raw(mtd, buf, offs, readlen);
329 for (j = 0; j < len; j++, buf += scanlen) {
330 if (check_pattern(buf, scanlen, mtd->writesize, bd))
337 * Scan a given block partially
339 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
340 loff_t offs, uint8_t *buf, int len)
342 struct mtd_oob_ops ops;
345 ops.ooblen = mtd->oobsize;
349 ops.mode = MTD_OOB_PLACE;
351 for (j = 0; j < len; j++) {
353 * Read the full oob until read_oob is fixed to
354 * handle single byte reads for 16 bit
357 ret = mtd->read_oob(mtd, offs, &ops);
361 if (check_short_pattern(buf, bd))
364 offs += mtd->writesize;
370 * create_bbt - [GENERIC] Create a bad block table by scanning the device
371 * @mtd: MTD device structure
372 * @buf: temporary buffer
373 * @bd: descriptor for the good/bad block search pattern
374 * @chip: create the table for a specific chip, -1 read all chips.
375 * Applies only if NAND_BBT_PERCHIP option is set
377 * Create a bad block table by scanning the device
378 * for the given good/bad block identify pattern
380 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
381 struct nand_bbt_descr *bd, int chip)
383 struct nand_chip *this = mtd->priv;
384 int i, numblocks, len, scanlen;
389 MTDDEBUG (MTD_DEBUG_LEVEL0, "Scanning device for bad blocks\n");
391 if (bd->options & NAND_BBT_SCANALLPAGES)
392 len = 1 << (this->bbt_erase_shift - this->page_shift);
394 if (bd->options & NAND_BBT_SCAN2NDPAGE)
400 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
401 /* We need only read few bytes from the OOB area */
405 /* Full page content should be read */
406 scanlen = mtd->writesize + mtd->oobsize;
407 readlen = len * mtd->writesize;
411 /* Note that numblocks is 2 * (real numblocks) here, see i+=2
412 * below as it makes shifting and masking less painful */
413 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
417 if (chip >= this->numchips) {
418 printk(KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
419 chip + 1, this->numchips);
422 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
423 startblock = chip * numblocks;
424 numblocks += startblock;
425 from = startblock << (this->bbt_erase_shift - 1);
428 for (i = startblock; i < numblocks;) {
431 if (bd->options & NAND_BBT_SCANALLPAGES)
432 ret = scan_block_full(mtd, bd, from, buf, readlen,
435 ret = scan_block_fast(mtd, bd, from, buf, len);
441 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
442 MTDDEBUG (MTD_DEBUG_LEVEL0,
443 "Bad eraseblock %d at 0x%08x\n",
444 i >> 1, (unsigned int)from);
445 mtd->ecc_stats.badblocks++;
449 from += (1 << this->bbt_erase_shift);
455 * search_bbt - [GENERIC] scan the device for a specific bad block table
456 * @mtd: MTD device structure
457 * @buf: temporary buffer
458 * @td: descriptor for the bad block table
460 * Read the bad block table by searching for a given ident pattern.
461 * Search is preformed either from the beginning up or from the end of
462 * the device downwards. The search starts always at the start of a
464 * If the option NAND_BBT_PERCHIP is given, each chip is searched
465 * for a bbt, which contains the bad block information of this chip.
466 * This is necessary to provide support for certain DOC devices.
468 * The bbt ident pattern resides in the oob area of the first page
471 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
473 struct nand_chip *this = mtd->priv;
475 int bits, startblock, block, dir;
476 int scanlen = mtd->writesize + mtd->oobsize;
478 int blocktopage = this->bbt_erase_shift - this->page_shift;
480 /* Search direction top -> down ? */
481 if (td->options & NAND_BBT_LASTBLOCK) {
482 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
489 /* Do we have a bbt per chip ? */
490 if (td->options & NAND_BBT_PERCHIP) {
491 chips = this->numchips;
492 bbtblocks = this->chipsize >> this->bbt_erase_shift;
493 startblock &= bbtblocks - 1;
496 bbtblocks = mtd->size >> this->bbt_erase_shift;
499 /* Number of bits for each erase block in the bbt */
500 bits = td->options & NAND_BBT_NRBITS_MSK;
502 for (i = 0; i < chips; i++) {
503 /* Reset version information */
506 /* Scan the maximum number of blocks */
507 for (block = 0; block < td->maxblocks; block++) {
509 int actblock = startblock + dir * block;
510 loff_t offs = actblock << this->bbt_erase_shift;
512 /* Read first page */
513 scan_read_raw(mtd, buf, offs, mtd->writesize);
514 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
515 td->pages[i] = actblock << blocktopage;
516 if (td->options & NAND_BBT_VERSION) {
517 td->version[i] = buf[mtd->writesize + td->veroffs];
522 startblock += this->chipsize >> this->bbt_erase_shift;
524 /* Check, if we found a bbt for each requested chip */
525 for (i = 0; i < chips; i++) {
526 if (td->pages[i] == -1)
527 printk(KERN_WARNING "Bad block table not found for chip %d\n", i);
529 printk(KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i],
536 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
537 * @mtd: MTD device structure
538 * @buf: temporary buffer
539 * @td: descriptor for the bad block table
540 * @md: descriptor for the bad block table mirror
542 * Search and read the bad block table(s)
544 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
546 /* Search the primary table */
547 search_bbt(mtd, buf, td);
549 /* Search the mirror table */
551 search_bbt(mtd, buf, md);
553 /* Force result check */
558 * write_bbt - [GENERIC] (Re)write the bad block table
560 * @mtd: MTD device structure
561 * @buf: temporary buffer
562 * @td: descriptor for the bad block table
563 * @md: descriptor for the bad block table mirror
564 * @chipsel: selector for a specific chip, -1 for all
566 * (Re)write the bad block table
569 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
570 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
573 struct nand_chip *this = mtd->priv;
574 struct erase_info einfo;
575 int i, j, res, chip = 0;
576 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
577 int nrchips, bbtoffs, pageoffs, ooboffs;
579 uint8_t rcode = td->reserved_block_code;
580 size_t retlen, len = 0;
582 struct mtd_oob_ops ops;
584 ops.ooblen = mtd->oobsize;
587 ops.mode = MTD_OOB_PLACE;
591 /* Write bad block table per chip rather than per device ? */
592 if (td->options & NAND_BBT_PERCHIP) {
593 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
594 /* Full device write or specific chip ? */
596 nrchips = this->numchips;
598 nrchips = chipsel + 1;
602 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
606 /* Loop through the chips */
607 for (; chip < nrchips; chip++) {
609 /* There was already a version of the table, reuse the page
610 * This applies for absolute placement too, as we have the
611 * page nr. in td->pages.
613 if (td->pages[chip] != -1) {
614 page = td->pages[chip];
618 /* Automatic placement of the bad block table */
619 /* Search direction top -> down ? */
620 if (td->options & NAND_BBT_LASTBLOCK) {
621 startblock = numblocks * (chip + 1) - 1;
624 startblock = chip * numblocks;
628 for (i = 0; i < td->maxblocks; i++) {
629 int block = startblock + dir * i;
630 /* Check, if the block is bad */
631 switch ((this->bbt[block >> 2] >>
632 (2 * (block & 0x03))) & 0x03) {
638 (this->bbt_erase_shift - this->page_shift);
639 /* Check, if the block is used by the mirror table */
640 if (!md || md->pages[chip] != page)
643 printk(KERN_ERR "No space left to write bad block table\n");
647 /* Set up shift count and masks for the flash table */
648 bits = td->options & NAND_BBT_NRBITS_MSK;
651 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
654 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
657 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
660 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
663 default: return -EINVAL;
666 bbtoffs = chip * (numblocks >> 2);
668 to = ((loff_t) page) << this->page_shift;
670 /* Must we save the block contents ? */
671 if (td->options & NAND_BBT_SAVECONTENT) {
672 /* Make it block aligned */
673 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
674 len = 1 << this->bbt_erase_shift;
675 res = mtd->read(mtd, to, len, &retlen, buf);
678 printk(KERN_INFO "nand_bbt: Error "
679 "reading block for writing "
680 "the bad block table\n");
683 printk(KERN_WARNING "nand_bbt: ECC error "
684 "while reading block for writing "
685 "bad block table\n");
688 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
689 ops.oobbuf = &buf[len];
690 res = mtd->read_oob(mtd, to + mtd->writesize, &ops);
691 if (res < 0 || ops.oobretlen != ops.ooblen)
694 /* Calc the byte offset in the buffer */
695 pageoffs = page - (int)(to >> this->page_shift);
696 offs = pageoffs << this->page_shift;
697 /* Preset the bbt area with 0xff */
698 memset(&buf[offs], 0xff, (size_t) (numblocks >> sft));
699 ooboffs = len + (pageoffs * mtd->oobsize);
703 len = (size_t) (numblocks >> sft);
704 /* Make it page aligned ! */
705 len = (len + (mtd->writesize - 1)) &
706 ~(mtd->writesize - 1);
707 /* Preset the buffer with 0xff */
708 memset(buf, 0xff, len +
709 (len >> this->page_shift)* mtd->oobsize);
712 /* Pattern is located in oob area of first page */
713 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
716 if (td->options & NAND_BBT_VERSION)
717 buf[ooboffs + td->veroffs] = td->version[chip];
719 /* walk through the memory table */
720 for (i = 0; i < numblocks;) {
722 dat = this->bbt[bbtoffs + (i >> 2)];
723 for (j = 0; j < 4; j++, i++) {
724 int sftcnt = (i << (3 - sft)) & sftmsk;
725 /* Do not store the reserved bbt blocks ! */
726 buf[offs + (i >> sft)] &=
727 ~(msk[dat & 0x03] << sftcnt);
732 memset(&einfo, 0, sizeof(einfo));
734 einfo.addr = (unsigned long)to;
735 einfo.len = 1 << this->bbt_erase_shift;
736 res = nand_erase_nand(mtd, &einfo, 1);
740 res = scan_write_bbt(mtd, to, len, buf, &buf[len]);
744 printk(KERN_DEBUG "Bad block table written to 0x%08x, version "
745 "0x%02X\n", (unsigned int)to, td->version[chip]);
747 /* Mark it as used */
748 td->pages[chip] = page;
754 "nand_bbt: Error while writing bad block table %d\n", res);
759 * nand_memory_bbt - [GENERIC] create a memory based bad block table
760 * @mtd: MTD device structure
761 * @bd: descriptor for the good/bad block search pattern
763 * The function creates a memory based bbt by scanning the device
764 * for manufacturer / software marked good / bad blocks
766 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
768 struct nand_chip *this = mtd->priv;
770 bd->options &= ~NAND_BBT_SCANEMPTY;
771 return create_bbt(mtd, this->buffers->databuf, bd, -1);
775 * check_create - [GENERIC] create and write bbt(s) if necessary
776 * @mtd: MTD device structure
777 * @buf: temporary buffer
778 * @bd: descriptor for the good/bad block search pattern
780 * The function checks the results of the previous call to read_bbt
781 * and creates / updates the bbt(s) if necessary
782 * Creation is necessary if no bbt was found for the chip/device
783 * Update is necessary if one of the tables is missing or the
784 * version nr. of one table is less than the other
786 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
788 int i, chips, writeops, chipsel, res;
789 struct nand_chip *this = mtd->priv;
790 struct nand_bbt_descr *td = this->bbt_td;
791 struct nand_bbt_descr *md = this->bbt_md;
792 struct nand_bbt_descr *rd, *rd2;
794 /* Do we have a bbt per chip ? */
795 if (td->options & NAND_BBT_PERCHIP)
796 chips = this->numchips;
800 for (i = 0; i < chips; i++) {
804 /* Per chip or per device ? */
805 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
806 /* Mirrored table avilable ? */
808 if (td->pages[i] == -1 && md->pages[i] == -1) {
813 if (td->pages[i] == -1) {
815 td->version[i] = md->version[i];
820 if (md->pages[i] == -1) {
822 md->version[i] = td->version[i];
827 if (td->version[i] == md->version[i]) {
829 if (!(td->options & NAND_BBT_VERSION))
834 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
836 md->version[i] = td->version[i];
840 td->version[i] = md->version[i];
847 if (td->pages[i] == -1) {
855 /* Create the bad block table by scanning the device ? */
856 if (!(td->options & NAND_BBT_CREATE))
859 /* Create the table in memory by scanning the chip(s) */
860 create_bbt(mtd, buf, bd, chipsel);
866 /* read back first ? */
868 read_abs_bbt(mtd, buf, rd, chipsel);
869 /* If they weren't versioned, read both. */
871 read_abs_bbt(mtd, buf, rd2, chipsel);
873 /* Write the bad block table to the device ? */
874 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
875 res = write_bbt(mtd, buf, td, md, chipsel);
880 /* Write the mirror bad block table to the device ? */
881 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
882 res = write_bbt(mtd, buf, md, td, chipsel);
891 * mark_bbt_regions - [GENERIC] mark the bad block table regions
892 * @mtd: MTD device structure
893 * @td: bad block table descriptor
895 * The bad block table regions are marked as "bad" to prevent
896 * accidental erasures / writes. The regions are identified by
899 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
901 struct nand_chip *this = mtd->priv;
902 int i, j, chips, block, nrblocks, update;
903 uint8_t oldval, newval;
905 /* Do we have a bbt per chip ? */
906 if (td->options & NAND_BBT_PERCHIP) {
907 chips = this->numchips;
908 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
911 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
914 for (i = 0; i < chips; i++) {
915 if ((td->options & NAND_BBT_ABSPAGE) ||
916 !(td->options & NAND_BBT_WRITE)) {
917 if (td->pages[i] == -1)
919 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
921 oldval = this->bbt[(block >> 3)];
922 newval = oldval | (0x2 << (block & 0x06));
923 this->bbt[(block >> 3)] = newval;
924 if ((oldval != newval) && td->reserved_block_code)
925 nand_update_bbt(mtd, block << (this->bbt_erase_shift - 1));
929 if (td->options & NAND_BBT_LASTBLOCK)
930 block = ((i + 1) * nrblocks) - td->maxblocks;
932 block = i * nrblocks;
934 for (j = 0; j < td->maxblocks; j++) {
935 oldval = this->bbt[(block >> 3)];
936 newval = oldval | (0x2 << (block & 0x06));
937 this->bbt[(block >> 3)] = newval;
938 if (oldval != newval)
942 /* If we want reserved blocks to be recorded to flash, and some
943 new ones have been marked, then we need to update the stored
944 bbts. This should only happen once. */
945 if (update && td->reserved_block_code)
946 nand_update_bbt(mtd, (block - 2) << (this->bbt_erase_shift - 1));
951 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
952 * @mtd: MTD device structure
953 * @bd: descriptor for the good/bad block search pattern
955 * The function checks, if a bad block table(s) is/are already
956 * available. If not it scans the device for manufacturer
957 * marked good / bad blocks and writes the bad block table(s) to
958 * the selected place.
960 * The bad block table memory is allocated here. It must be freed
961 * by calling the nand_free_bbt function.
964 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
966 struct nand_chip *this = mtd->priv;
969 struct nand_bbt_descr *td = this->bbt_td;
970 struct nand_bbt_descr *md = this->bbt_md;
972 len = mtd->size >> (this->bbt_erase_shift + 2);
973 /* Allocate memory (2bit per block) and clear the memory bad block table */
974 this->bbt = kzalloc(len, GFP_KERNEL);
976 printk(KERN_ERR "nand_scan_bbt: Out of memory\n");
980 /* If no primary table decriptor is given, scan the device
981 * to build a memory based bad block table
984 if ((res = nand_memory_bbt(mtd, bd))) {
985 printk(KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
992 /* Allocate a temporary buffer for one eraseblock incl. oob */
993 len = (1 << this->bbt_erase_shift);
994 len += (len >> this->page_shift) * mtd->oobsize;
997 printk(KERN_ERR "nand_bbt: Out of memory\n");
1003 /* Is the bbt at a given page ? */
1004 if (td->options & NAND_BBT_ABSPAGE) {
1005 res = read_abs_bbts(mtd, buf, td, md);
1007 /* Search the bad block table using a pattern in oob */
1008 res = search_read_bbts(mtd, buf, td, md);
1012 res = check_create(mtd, buf, bd);
1014 /* Prevent the bbt regions from erasing / writing */
1015 mark_bbt_region(mtd, td);
1017 mark_bbt_region(mtd, md);
1024 * nand_update_bbt - [NAND Interface] update bad block table(s)
1025 * @mtd: MTD device structure
1026 * @offs: the offset of the newly marked block
1028 * The function updates the bad block table(s)
1030 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1032 struct nand_chip *this = mtd->priv;
1033 int len, res = 0, writeops = 0;
1036 struct nand_bbt_descr *td = this->bbt_td;
1037 struct nand_bbt_descr *md = this->bbt_md;
1039 if (!this->bbt || !td)
1042 len = mtd->size >> (this->bbt_erase_shift + 2);
1043 /* Allocate a temporary buffer for one eraseblock incl. oob */
1044 len = (1 << this->bbt_erase_shift);
1045 len += (len >> this->page_shift) * mtd->oobsize;
1046 buf = kmalloc(len, GFP_KERNEL);
1048 printk(KERN_ERR "nand_update_bbt: Out of memory\n");
1052 writeops = md != NULL ? 0x03 : 0x01;
1054 /* Do we have a bbt per chip ? */
1055 if (td->options & NAND_BBT_PERCHIP) {
1056 chip = (int)(offs >> this->chip_shift);
1063 td->version[chip]++;
1065 md->version[chip]++;
1067 /* Write the bad block table to the device ? */
1068 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1069 res = write_bbt(mtd, buf, td, md, chipsel);
1073 /* Write the mirror bad block table to the device ? */
1074 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1075 res = write_bbt(mtd, buf, md, td, chipsel);
1083 /* Define some generic bad / good block scan pattern which are used
1084 * while scanning a device for factory marked good / bad blocks. */
1085 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1087 static struct nand_bbt_descr smallpage_memorybased = {
1088 .options = NAND_BBT_SCAN2NDPAGE,
1091 .pattern = scan_ff_pattern
1094 static struct nand_bbt_descr largepage_memorybased = {
1098 .pattern = scan_ff_pattern
1101 static struct nand_bbt_descr smallpage_flashbased = {
1102 .options = NAND_BBT_SCAN2NDPAGE,
1105 .pattern = scan_ff_pattern
1108 static struct nand_bbt_descr largepage_flashbased = {
1109 .options = NAND_BBT_SCAN2NDPAGE,
1112 .pattern = scan_ff_pattern
1115 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1117 static struct nand_bbt_descr agand_flashbased = {
1118 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1121 .pattern = scan_agand_pattern
1124 /* Generic flash bbt decriptors
1126 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1127 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1129 static struct nand_bbt_descr bbt_main_descr = {
1130 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1131 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1136 .pattern = bbt_pattern
1139 static struct nand_bbt_descr bbt_mirror_descr = {
1140 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1141 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1146 .pattern = mirror_pattern
1150 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1151 * @mtd: MTD device structure
1153 * This function selects the default bad block table
1154 * support for the device and calls the nand_scan_bbt function
1157 int nand_default_bbt(struct mtd_info *mtd)
1159 struct nand_chip *this = mtd->priv;
1161 /* Default for AG-AND. We must use a flash based
1162 * bad block table as the devices have factory marked
1163 * _good_ blocks. Erasing those blocks leads to loss
1164 * of the good / bad information, so we _must_ store
1165 * this information in a good / bad table during
1168 if (this->options & NAND_IS_AND) {
1169 /* Use the default pattern descriptors */
1170 if (!this->bbt_td) {
1171 this->bbt_td = &bbt_main_descr;
1172 this->bbt_md = &bbt_mirror_descr;
1174 this->options |= NAND_USE_FLASH_BBT;
1175 return nand_scan_bbt(mtd, &agand_flashbased);
1178 /* Is a flash based bad block table requested ? */
1179 if (this->options & NAND_USE_FLASH_BBT) {
1180 /* Use the default pattern descriptors */
1181 if (!this->bbt_td) {
1182 this->bbt_td = &bbt_main_descr;
1183 this->bbt_md = &bbt_mirror_descr;
1185 if (!this->badblock_pattern) {
1186 this->badblock_pattern = (mtd->writesize > 512) ? &largepage_flashbased : &smallpage_flashbased;
1189 this->bbt_td = NULL;
1190 this->bbt_md = NULL;
1191 if (!this->badblock_pattern) {
1192 this->badblock_pattern = (mtd->writesize > 512) ?
1193 &largepage_memorybased : &smallpage_memorybased;
1196 return nand_scan_bbt(mtd, this->badblock_pattern);
1200 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1201 * @mtd: MTD device structure
1202 * @offs: offset in the device
1203 * @allowbbt: allow access to bad block table region
1206 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1208 struct nand_chip *this = mtd->priv;
1212 /* Get block number * 2 */
1213 block = (int)(offs >> (this->bbt_erase_shift - 1));
1214 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1216 MTDDEBUG (MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: "
1217 "(block %d) 0x%02x\n", (unsigned int)offs, res, block >> 1);
1225 return allowbbt ? 0 : 1;
1230 /* XXX U-BOOT XXX */
1232 EXPORT_SYMBOL(nand_scan_bbt);
1233 EXPORT_SYMBOL(nand_default_bbt);