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22 * If one of the bbt's is out of date or does not exist it is (re)created.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
53 #include <linux/slab.h>
54 #include <linux/types.h>
55 #include <linux/mtd/mtd.h>
56 #include <linux/mtd/nand.h>
57 #include <linux/mtd/nand_ecc.h>
58 #include <linux/mtd/compatmac.h>
59 #include <linux/bitops.h>
60 #include <linux/delay.h>
61 #include <linux/vmalloc.h>
64 * check_pattern - [GENERIC] check if a pattern is in the buffer
65 * @buf: the buffer to search
66 * @len: the length of buffer to search
67 * @paglen: the pagelength
68 * @td: search pattern descriptor
70 * Check for a pattern at the given place. Used to search bad block
71 * tables and good / bad block identifiers.
72 * If the SCAN_EMPTY option is set then check, if all bytes except the
73 * pattern area contain 0xff
76 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
81 end = paglen + td->offs;
82 if (td->options & NAND_BBT_SCANEMPTY) {
83 for (i = 0; i < end; i++) {
90 /* Compare the pattern */
91 for (i = 0; i < td->len; i++) {
92 if (p[i] != td->pattern[i])
96 if (td->options & NAND_BBT_SCANEMPTY) {
99 for (i = end; i < len; i++) {
108 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
109 * @buf: the buffer to search
110 * @td: search pattern descriptor
112 * Check for a pattern at the given place. Used to search bad block
113 * tables and good / bad block identifiers. Same as check_pattern, but
114 * no optional empty check
117 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
122 /* Compare the pattern */
123 for (i = 0; i < td->len; i++) {
124 if (p[td->offs + i] != td->pattern[i])
131 * read_bbt - [GENERIC] Read the bad block table starting from page
132 * @mtd: MTD device structure
133 * @buf: temporary buffer
134 * @page: the starting page
135 * @num: the number of bbt descriptors to read
136 * @bits: number of bits per block
137 * @offs: offset in the memory table
138 * @reserved_block_code: Pattern to identify reserved blocks
140 * Read the bad block table starting from page.
143 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
144 int bits, int offs, int reserved_block_code)
146 int res, i, j, act = 0;
147 struct nand_chip *this = mtd->priv;
148 size_t retlen, len, totlen;
150 uint8_t msk = (uint8_t) ((1 << bits) - 1);
152 totlen = (num * bits) >> 3;
153 from = ((loff_t) page) << this->page_shift;
156 len = min(totlen, (size_t) (1 << this->bbt_erase_shift));
157 res = mtd->read(mtd, from, len, &retlen, buf);
160 printk(KERN_INFO "nand_bbt: Error reading bad block table\n");
163 printk(KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
167 for (i = 0; i < len; i++) {
168 uint8_t dat = buf[i];
169 for (j = 0; j < 8; j += bits, act += 2) {
170 uint8_t tmp = (dat >> j) & msk;
173 if (reserved_block_code && (tmp == reserved_block_code)) {
174 printk(KERN_DEBUG "nand_read_bbt: Reserved block at 0x%012llx\n",
175 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
176 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
177 mtd->ecc_stats.bbtblocks++;
180 /* Leave it for now, if its matured we can move this
181 * message to MTD_DEBUG_LEVEL0 */
182 printk(KERN_DEBUG "nand_read_bbt: Bad block at 0x%012llx\n",
183 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
184 /* Factory marked bad or worn out ? */
186 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
188 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
189 mtd->ecc_stats.badblocks++;
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 * Scan read raw data from flash
236 static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
239 struct mtd_oob_ops ops;
242 ops.mode = MTD_OOB_RAW;
244 ops.ooblen = mtd->oobsize;
248 if (len <= mtd->writesize) {
249 ops.oobbuf = buf + len;
252 return mtd->read_oob(mtd, offs, &ops);
254 ops.oobbuf = buf + mtd->writesize;
256 ops.len = mtd->writesize;
257 res = mtd->read_oob(mtd, offs, &ops);
263 buf += mtd->oobsize + mtd->writesize;
264 len -= mtd->writesize;
270 * Scan write data with oob to flash
272 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
273 uint8_t *buf, uint8_t *oob)
275 struct mtd_oob_ops ops;
277 ops.mode = MTD_OOB_PLACE;
279 ops.ooblen = mtd->oobsize;
284 return mtd->write_oob(mtd, offs, &ops);
288 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
289 * @mtd: MTD device structure
290 * @buf: temporary buffer
291 * @td: descriptor for the bad block table
292 * @md: descriptor for the bad block table mirror
294 * Read the bad block table(s) for all chips starting at a given page
295 * We assume that the bbt bits are in consecutive order.
298 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
299 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
301 struct nand_chip *this = mtd->priv;
303 /* Read the primary version, if available */
304 if (td->options & NAND_BBT_VERSION) {
305 scan_read_raw(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
307 td->version[0] = buf[mtd->writesize + td->veroffs];
308 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
309 td->pages[0], td->version[0]);
312 /* Read the mirror version, if available */
313 if (md && (md->options & NAND_BBT_VERSION)) {
314 scan_read_raw(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
316 md->version[0] = buf[mtd->writesize + md->veroffs];
317 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
318 md->pages[0], md->version[0]);
324 * Scan a given block full
326 static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
327 loff_t offs, uint8_t *buf, size_t readlen,
328 int scanlen, int len)
332 ret = scan_read_raw(mtd, buf, offs, readlen);
336 for (j = 0; j < len; j++, buf += scanlen) {
337 if (check_pattern(buf, scanlen, mtd->writesize, bd))
344 * Scan a given block partially
346 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
347 loff_t offs, uint8_t *buf, int len)
349 struct mtd_oob_ops ops;
352 ops.ooblen = mtd->oobsize;
356 ops.mode = MTD_OOB_PLACE;
358 for (j = 0; j < len; j++) {
360 * Read the full oob until read_oob is fixed to
361 * handle single byte reads for 16 bit
364 ret = mtd->read_oob(mtd, offs, &ops);
368 if (check_short_pattern(buf, bd))
371 offs += mtd->writesize;
377 * create_bbt - [GENERIC] Create a bad block table by scanning the device
378 * @mtd: MTD device structure
379 * @buf: temporary buffer
380 * @bd: descriptor for the good/bad block search pattern
381 * @chip: create the table for a specific chip, -1 read all chips.
382 * Applies only if NAND_BBT_PERCHIP option is set
384 * Create a bad block table by scanning the device
385 * for the given good/bad block identify pattern
387 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
388 struct nand_bbt_descr *bd, int chip)
390 struct nand_chip *this = mtd->priv;
391 int i, numblocks, len, scanlen;
396 printk(KERN_INFO "Scanning device for bad blocks\n");
398 if (bd->options & NAND_BBT_SCANALLPAGES)
399 len = 1 << (this->bbt_erase_shift - this->page_shift);
401 if (bd->options & NAND_BBT_SCAN2NDPAGE)
407 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
408 /* We need only read few bytes from the OOB area */
412 /* Full page content should be read */
413 scanlen = mtd->writesize + mtd->oobsize;
414 readlen = len * mtd->writesize;
418 /* Note that numblocks is 2 * (real numblocks) here, see i+=2
419 * below as it makes shifting and masking less painful */
420 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
424 if (chip >= this->numchips) {
425 printk(KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
426 chip + 1, this->numchips);
429 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
430 startblock = chip * numblocks;
431 numblocks += startblock;
432 from = (loff_t)startblock << (this->bbt_erase_shift - 1);
435 if (this->options & NAND_BBT_SCANLASTPAGE)
436 from += mtd->erasesize - (mtd->writesize * len);
438 for (i = startblock; i < numblocks;) {
441 if (bd->options & NAND_BBT_SCANALLPAGES)
442 ret = scan_block_full(mtd, bd, from, buf, readlen,
445 ret = scan_block_fast(mtd, bd, from, buf, len);
451 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
452 printk(KERN_WARNING "Bad eraseblock %d at 0x%012llx\n",
453 i >> 1, (unsigned long long)from);
454 mtd->ecc_stats.badblocks++;
458 from += (1 << this->bbt_erase_shift);
464 * search_bbt - [GENERIC] scan the device for a specific bad block table
465 * @mtd: MTD device structure
466 * @buf: temporary buffer
467 * @td: descriptor for the bad block table
469 * Read the bad block table by searching for a given ident pattern.
470 * Search is preformed either from the beginning up or from the end of
471 * the device downwards. The search starts always at the start of a
473 * If the option NAND_BBT_PERCHIP is given, each chip is searched
474 * for a bbt, which contains the bad block information of this chip.
475 * This is necessary to provide support for certain DOC devices.
477 * The bbt ident pattern resides in the oob area of the first page
480 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
482 struct nand_chip *this = mtd->priv;
484 int bits, startblock, block, dir;
485 int scanlen = mtd->writesize + mtd->oobsize;
487 int blocktopage = this->bbt_erase_shift - this->page_shift;
489 /* Search direction top -> down ? */
490 if (td->options & NAND_BBT_LASTBLOCK) {
491 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
498 /* Do we have a bbt per chip ? */
499 if (td->options & NAND_BBT_PERCHIP) {
500 chips = this->numchips;
501 bbtblocks = this->chipsize >> this->bbt_erase_shift;
502 startblock &= bbtblocks - 1;
505 bbtblocks = mtd->size >> this->bbt_erase_shift;
508 /* Number of bits for each erase block in the bbt */
509 bits = td->options & NAND_BBT_NRBITS_MSK;
511 for (i = 0; i < chips; i++) {
512 /* Reset version information */
515 /* Scan the maximum number of blocks */
516 for (block = 0; block < td->maxblocks; block++) {
518 int actblock = startblock + dir * block;
519 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
521 /* Read first page */
522 scan_read_raw(mtd, buf, offs, mtd->writesize);
523 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
524 td->pages[i] = actblock << blocktopage;
525 if (td->options & NAND_BBT_VERSION) {
526 td->version[i] = buf[mtd->writesize + td->veroffs];
531 startblock += this->chipsize >> this->bbt_erase_shift;
533 /* Check, if we found a bbt for each requested chip */
534 for (i = 0; i < chips; i++) {
535 if (td->pages[i] == -1)
536 printk(KERN_WARNING "Bad block table not found for chip %d\n", i);
538 printk(KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i],
545 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
546 * @mtd: MTD device structure
547 * @buf: temporary buffer
548 * @td: descriptor for the bad block table
549 * @md: descriptor for the bad block table mirror
551 * Search and read the bad block table(s)
553 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
555 /* Search the primary table */
556 search_bbt(mtd, buf, td);
558 /* Search the mirror table */
560 search_bbt(mtd, buf, md);
562 /* Force result check */
567 * write_bbt - [GENERIC] (Re)write the bad block table
569 * @mtd: MTD device structure
570 * @buf: temporary buffer
571 * @td: descriptor for the bad block table
572 * @md: descriptor for the bad block table mirror
573 * @chipsel: selector for a specific chip, -1 for all
575 * (Re)write the bad block table
578 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
579 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
582 struct nand_chip *this = mtd->priv;
583 struct erase_info einfo;
584 int i, j, res, chip = 0;
585 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
586 int nrchips, bbtoffs, pageoffs, ooboffs;
588 uint8_t rcode = td->reserved_block_code;
589 size_t retlen, len = 0;
591 struct mtd_oob_ops ops;
593 ops.ooblen = mtd->oobsize;
596 ops.mode = MTD_OOB_PLACE;
600 /* Write bad block table per chip rather than per device ? */
601 if (td->options & NAND_BBT_PERCHIP) {
602 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
603 /* Full device write or specific chip ? */
605 nrchips = this->numchips;
607 nrchips = chipsel + 1;
611 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
615 /* Loop through the chips */
616 for (; chip < nrchips; chip++) {
618 /* There was already a version of the table, reuse the page
619 * This applies for absolute placement too, as we have the
620 * page nr. in td->pages.
622 if (td->pages[chip] != -1) {
623 page = td->pages[chip];
627 /* Automatic placement of the bad block table */
628 /* Search direction top -> down ? */
629 if (td->options & NAND_BBT_LASTBLOCK) {
630 startblock = numblocks * (chip + 1) - 1;
633 startblock = chip * numblocks;
637 for (i = 0; i < td->maxblocks; i++) {
638 int block = startblock + dir * i;
639 /* Check, if the block is bad */
640 switch ((this->bbt[block >> 2] >>
641 (2 * (block & 0x03))) & 0x03) {
647 (this->bbt_erase_shift - this->page_shift);
648 /* Check, if the block is used by the mirror table */
649 if (!md || md->pages[chip] != page)
652 printk(KERN_ERR "No space left to write bad block table\n");
656 /* Set up shift count and masks for the flash table */
657 bits = td->options & NAND_BBT_NRBITS_MSK;
660 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
663 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
666 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
669 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
672 default: return -EINVAL;
675 bbtoffs = chip * (numblocks >> 2);
677 to = ((loff_t) page) << this->page_shift;
679 /* Must we save the block contents ? */
680 if (td->options & NAND_BBT_SAVECONTENT) {
681 /* Make it block aligned */
682 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
683 len = 1 << this->bbt_erase_shift;
684 res = mtd->read(mtd, to, len, &retlen, buf);
687 printk(KERN_INFO "nand_bbt: Error "
688 "reading block for writing "
689 "the bad block table\n");
692 printk(KERN_WARNING "nand_bbt: ECC error "
693 "while reading block for writing "
694 "bad block table\n");
697 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
698 ops.oobbuf = &buf[len];
699 res = mtd->read_oob(mtd, to + mtd->writesize, &ops);
700 if (res < 0 || ops.oobretlen != ops.ooblen)
703 /* Calc the byte offset in the buffer */
704 pageoffs = page - (int)(to >> this->page_shift);
705 offs = pageoffs << this->page_shift;
706 /* Preset the bbt area with 0xff */
707 memset(&buf[offs], 0xff, (size_t) (numblocks >> sft));
708 ooboffs = len + (pageoffs * mtd->oobsize);
712 len = (size_t) (numblocks >> sft);
713 /* Make it page aligned ! */
714 len = (len + (mtd->writesize - 1)) &
715 ~(mtd->writesize - 1);
716 /* Preset the buffer with 0xff */
717 memset(buf, 0xff, len +
718 (len >> this->page_shift)* mtd->oobsize);
721 /* Pattern is located in oob area of first page */
722 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
725 if (td->options & NAND_BBT_VERSION)
726 buf[ooboffs + td->veroffs] = td->version[chip];
728 /* walk through the memory table */
729 for (i = 0; i < numblocks;) {
731 dat = this->bbt[bbtoffs + (i >> 2)];
732 for (j = 0; j < 4; j++, i++) {
733 int sftcnt = (i << (3 - sft)) & sftmsk;
734 /* Do not store the reserved bbt blocks ! */
735 buf[offs + (i >> sft)] &=
736 ~(msk[dat & 0x03] << sftcnt);
741 memset(&einfo, 0, sizeof(einfo));
744 einfo.len = 1 << this->bbt_erase_shift;
745 res = nand_erase_nand(mtd, &einfo, 1);
749 res = scan_write_bbt(mtd, to, len, buf, &buf[len]);
753 printk(KERN_DEBUG "Bad block table written to 0x%012llx, version "
754 "0x%02X\n", (unsigned long long)to, td->version[chip]);
756 /* Mark it as used */
757 td->pages[chip] = page;
763 "nand_bbt: Error while writing bad block table %d\n", res);
768 * nand_memory_bbt - [GENERIC] create a memory based bad block table
769 * @mtd: MTD device structure
770 * @bd: descriptor for the good/bad block search pattern
772 * The function creates a memory based bbt by scanning the device
773 * for manufacturer / software marked good / bad blocks
775 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
777 struct nand_chip *this = mtd->priv;
779 bd->options &= ~NAND_BBT_SCANEMPTY;
780 return create_bbt(mtd, this->buffers->databuf, bd, -1);
784 * check_create - [GENERIC] create and write bbt(s) if necessary
785 * @mtd: MTD device structure
786 * @buf: temporary buffer
787 * @bd: descriptor for the good/bad block search pattern
789 * The function checks the results of the previous call to read_bbt
790 * and creates / updates the bbt(s) if necessary
791 * Creation is necessary if no bbt was found for the chip/device
792 * Update is necessary if one of the tables is missing or the
793 * version nr. of one table is less than the other
795 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
797 int i, chips, writeops, chipsel, res;
798 struct nand_chip *this = mtd->priv;
799 struct nand_bbt_descr *td = this->bbt_td;
800 struct nand_bbt_descr *md = this->bbt_md;
801 struct nand_bbt_descr *rd, *rd2;
803 /* Do we have a bbt per chip ? */
804 if (td->options & NAND_BBT_PERCHIP)
805 chips = this->numchips;
809 for (i = 0; i < chips; i++) {
813 /* Per chip or per device ? */
814 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
815 /* Mirrored table avilable ? */
817 if (td->pages[i] == -1 && md->pages[i] == -1) {
822 if (td->pages[i] == -1) {
824 td->version[i] = md->version[i];
829 if (md->pages[i] == -1) {
831 md->version[i] = td->version[i];
836 if (td->version[i] == md->version[i]) {
838 if (!(td->options & NAND_BBT_VERSION))
843 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
845 md->version[i] = td->version[i];
849 td->version[i] = md->version[i];
856 if (td->pages[i] == -1) {
864 /* Create the bad block table by scanning the device ? */
865 if (!(td->options & NAND_BBT_CREATE))
868 /* Create the table in memory by scanning the chip(s) */
869 create_bbt(mtd, buf, bd, chipsel);
875 /* read back first ? */
877 read_abs_bbt(mtd, buf, rd, chipsel);
878 /* If they weren't versioned, read both. */
880 read_abs_bbt(mtd, buf, rd2, chipsel);
882 /* Write the bad block table to the device ? */
883 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
884 res = write_bbt(mtd, buf, td, md, chipsel);
889 /* Write the mirror bad block table to the device ? */
890 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
891 res = write_bbt(mtd, buf, md, td, chipsel);
900 * mark_bbt_regions - [GENERIC] mark the bad block table regions
901 * @mtd: MTD device structure
902 * @td: bad block table descriptor
904 * The bad block table regions are marked as "bad" to prevent
905 * accidental erasures / writes. The regions are identified by
908 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
910 struct nand_chip *this = mtd->priv;
911 int i, j, chips, block, nrblocks, update;
912 uint8_t oldval, newval;
914 /* Do we have a bbt per chip ? */
915 if (td->options & NAND_BBT_PERCHIP) {
916 chips = this->numchips;
917 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
920 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
923 for (i = 0; i < chips; i++) {
924 if ((td->options & NAND_BBT_ABSPAGE) ||
925 !(td->options & NAND_BBT_WRITE)) {
926 if (td->pages[i] == -1)
928 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
930 oldval = this->bbt[(block >> 3)];
931 newval = oldval | (0x2 << (block & 0x06));
932 this->bbt[(block >> 3)] = newval;
933 if ((oldval != newval) && td->reserved_block_code)
934 nand_update_bbt(mtd, (loff_t)block << (this->bbt_erase_shift - 1));
938 if (td->options & NAND_BBT_LASTBLOCK)
939 block = ((i + 1) * nrblocks) - td->maxblocks;
941 block = i * nrblocks;
943 for (j = 0; j < td->maxblocks; j++) {
944 oldval = this->bbt[(block >> 3)];
945 newval = oldval | (0x2 << (block & 0x06));
946 this->bbt[(block >> 3)] = newval;
947 if (oldval != newval)
951 /* If we want reserved blocks to be recorded to flash, and some
952 new ones have been marked, then we need to update the stored
953 bbts. This should only happen once. */
954 if (update && td->reserved_block_code)
955 nand_update_bbt(mtd, (loff_t)(block - 2) << (this->bbt_erase_shift - 1));
960 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
961 * @mtd: MTD device structure
962 * @bd: descriptor for the good/bad block search pattern
964 * The function checks, if a bad block table(s) is/are already
965 * available. If not it scans the device for manufacturer
966 * marked good / bad blocks and writes the bad block table(s) to
967 * the selected place.
969 * The bad block table memory is allocated here. It must be freed
970 * by calling the nand_free_bbt function.
973 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
975 struct nand_chip *this = mtd->priv;
978 struct nand_bbt_descr *td = this->bbt_td;
979 struct nand_bbt_descr *md = this->bbt_md;
981 len = mtd->size >> (this->bbt_erase_shift + 2);
982 /* Allocate memory (2bit per block) and clear the memory bad block table */
983 this->bbt = kzalloc(len, GFP_KERNEL);
985 printk(KERN_ERR "nand_scan_bbt: Out of memory\n");
989 /* If no primary table decriptor is given, scan the device
990 * to build a memory based bad block table
993 if ((res = nand_memory_bbt(mtd, bd))) {
994 printk(KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
1001 /* Allocate a temporary buffer for one eraseblock incl. oob */
1002 len = (1 << this->bbt_erase_shift);
1003 len += (len >> this->page_shift) * mtd->oobsize;
1006 printk(KERN_ERR "nand_bbt: Out of memory\n");
1012 /* Is the bbt at a given page ? */
1013 if (td->options & NAND_BBT_ABSPAGE) {
1014 res = read_abs_bbts(mtd, buf, td, md);
1016 /* Search the bad block table using a pattern in oob */
1017 res = search_read_bbts(mtd, buf, td, md);
1021 res = check_create(mtd, buf, bd);
1023 /* Prevent the bbt regions from erasing / writing */
1024 mark_bbt_region(mtd, td);
1026 mark_bbt_region(mtd, md);
1033 * nand_update_bbt - [NAND Interface] update bad block table(s)
1034 * @mtd: MTD device structure
1035 * @offs: the offset of the newly marked block
1037 * The function updates the bad block table(s)
1039 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1041 struct nand_chip *this = mtd->priv;
1042 int len, res = 0, writeops = 0;
1045 struct nand_bbt_descr *td = this->bbt_td;
1046 struct nand_bbt_descr *md = this->bbt_md;
1048 if (!this->bbt || !td)
1051 /* Allocate a temporary buffer for one eraseblock incl. oob */
1052 len = (1 << this->bbt_erase_shift);
1053 len += (len >> this->page_shift) * mtd->oobsize;
1054 buf = kmalloc(len, GFP_KERNEL);
1056 printk(KERN_ERR "nand_update_bbt: Out of memory\n");
1060 writeops = md != NULL ? 0x03 : 0x01;
1062 /* Do we have a bbt per chip ? */
1063 if (td->options & NAND_BBT_PERCHIP) {
1064 chip = (int)(offs >> this->chip_shift);
1071 td->version[chip]++;
1073 md->version[chip]++;
1075 /* Write the bad block table to the device ? */
1076 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1077 res = write_bbt(mtd, buf, td, md, chipsel);
1081 /* Write the mirror bad block table to the device ? */
1082 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1083 res = write_bbt(mtd, buf, md, td, chipsel);
1091 /* Define some generic bad / good block scan pattern which are used
1092 * while scanning a device for factory marked good / bad blocks. */
1093 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1095 static struct nand_bbt_descr smallpage_memorybased = {
1096 .options = NAND_BBT_SCAN2NDPAGE,
1099 .pattern = scan_ff_pattern
1102 static struct nand_bbt_descr largepage_memorybased = {
1106 .pattern = scan_ff_pattern
1109 static struct nand_bbt_descr smallpage_flashbased = {
1110 .options = NAND_BBT_SCAN2NDPAGE,
1113 .pattern = scan_ff_pattern
1116 static struct nand_bbt_descr largepage_flashbased = {
1117 .options = NAND_BBT_SCAN2NDPAGE,
1120 .pattern = scan_ff_pattern
1123 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1125 static struct nand_bbt_descr agand_flashbased = {
1126 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1129 .pattern = scan_agand_pattern
1132 /* Generic flash bbt decriptors
1134 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1135 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1137 static struct nand_bbt_descr bbt_main_descr = {
1138 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1139 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1144 .pattern = bbt_pattern
1147 static struct nand_bbt_descr bbt_mirror_descr = {
1148 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1149 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1154 .pattern = mirror_pattern
1158 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1159 * @mtd: MTD device structure
1161 * This function selects the default bad block table
1162 * support for the device and calls the nand_scan_bbt function
1165 int nand_default_bbt(struct mtd_info *mtd)
1167 struct nand_chip *this = mtd->priv;
1169 /* Default for AG-AND. We must use a flash based
1170 * bad block table as the devices have factory marked
1171 * _good_ blocks. Erasing those blocks leads to loss
1172 * of the good / bad information, so we _must_ store
1173 * this information in a good / bad table during
1176 if (this->options & NAND_IS_AND) {
1177 /* Use the default pattern descriptors */
1178 if (!this->bbt_td) {
1179 this->bbt_td = &bbt_main_descr;
1180 this->bbt_md = &bbt_mirror_descr;
1182 this->options |= NAND_USE_FLASH_BBT;
1183 return nand_scan_bbt(mtd, &agand_flashbased);
1186 /* Is a flash based bad block table requested ? */
1187 if (this->options & NAND_USE_FLASH_BBT) {
1188 /* Use the default pattern descriptors */
1189 if (!this->bbt_td) {
1190 this->bbt_td = &bbt_main_descr;
1191 this->bbt_md = &bbt_mirror_descr;
1193 if (!this->badblock_pattern) {
1194 this->badblock_pattern = (mtd->writesize > 512) ? &largepage_flashbased : &smallpage_flashbased;
1197 this->bbt_td = NULL;
1198 this->bbt_md = NULL;
1199 if (!this->badblock_pattern) {
1200 this->badblock_pattern = (mtd->writesize > 512) ?
1201 &largepage_memorybased : &smallpage_memorybased;
1204 return nand_scan_bbt(mtd, this->badblock_pattern);
1208 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1209 * @mtd: MTD device structure
1210 * @offs: offset in the device
1211 * @allowbbt: allow access to bad block table region
1214 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1216 struct nand_chip *this = mtd->priv;
1220 /* Get block number * 2 */
1221 block = (int)(offs >> (this->bbt_erase_shift - 1));
1222 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1224 DEBUG(MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1225 (unsigned int)offs, block >> 1, res);
1233 return allowbbt ? 0 : 1;
1238 EXPORT_SYMBOL(nand_scan_bbt);
1239 EXPORT_SYMBOL(nand_default_bbt);