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24 * If one of the bbt's is out of date or does not exist it is (re)created.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
57 #if defined(CONFIG_CMD_NAND) && !defined(CFG_NAND_LEGACY)
60 #include <linux/mtd/compat.h>
61 #include <linux/mtd/mtd.h>
62 #include <linux/mtd/nand.h>
64 #include <asm/errno.h>
68 #include <linux/slab.h>
69 #include <linux/types.h>
70 #include <linux/mtd/mtd.h>
71 #include <linux/mtd/nand.h>
72 #include <linux/mtd/nand_ecc.h>
73 #include <linux/mtd/compatmac.h>
74 #include <linux/bitops.h>
75 #include <linux/delay.h>
76 #include <linux/vmalloc.h>
80 * check_pattern - [GENERIC] check if a pattern is in the buffer
81 * @buf: the buffer to search
82 * @len: the length of buffer to search
83 * @paglen: the pagelength
84 * @td: search pattern descriptor
86 * Check for a pattern at the given place. Used to search bad block
87 * tables and good / bad block identifiers.
88 * If the SCAN_EMPTY option is set then check, if all bytes except the
89 * pattern area contain 0xff
92 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
97 end = paglen + td->offs;
98 if (td->options & NAND_BBT_SCANEMPTY) {
99 for (i = 0; i < end; i++) {
106 /* Compare the pattern */
107 for (i = 0; i < td->len; i++) {
108 if (p[i] != td->pattern[i])
112 if (td->options & NAND_BBT_SCANEMPTY) {
115 for (i = end; i < len; i++) {
124 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
125 * @buf: the buffer to search
126 * @td: search pattern descriptor
128 * Check for a pattern at the given place. Used to search bad block
129 * tables and good / bad block identifiers. Same as check_pattern, but
130 * no optional empty check
133 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
138 /* Compare the pattern */
139 for (i = 0; i < td->len; i++) {
140 if (p[td->offs + i] != td->pattern[i])
147 * read_bbt - [GENERIC] Read the bad block table starting from page
148 * @mtd: MTD device structure
149 * @buf: temporary buffer
150 * @page: the starting page
151 * @num: the number of bbt descriptors to read
152 * @bits: number of bits per block
153 * @offs: offset in the memory table
154 * @reserved_block_code: Pattern to identify reserved blocks
156 * Read the bad block table starting from page.
159 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
160 int bits, int offs, int reserved_block_code)
162 int res, i, j, act = 0;
163 struct nand_chip *this = mtd->priv;
164 size_t retlen, len, totlen;
166 uint8_t msk = (uint8_t) ((1 << bits) - 1);
168 totlen = (num * bits) >> 3;
169 from = ((loff_t) page) << this->page_shift;
172 len = min(totlen, (size_t) (1 << this->bbt_erase_shift));
173 res = mtd->read(mtd, from, len, &retlen, buf);
176 printk(KERN_INFO "nand_bbt: Error reading bad block table\n");
179 printk(KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
183 for (i = 0; i < len; i++) {
184 uint8_t dat = buf[i];
185 for (j = 0; j < 8; j += bits, act += 2) {
186 uint8_t tmp = (dat >> j) & msk;
189 if (reserved_block_code && (tmp == reserved_block_code)) {
190 printk(KERN_DEBUG "nand_read_bbt: Reserved block at 0x%08x\n",
191 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
192 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
193 mtd->ecc_stats.bbtblocks++;
196 /* Leave it for now, if its matured we can move this
197 * message to MTD_DEBUG_LEVEL0 */
198 printk(KERN_DEBUG "nand_read_bbt: Bad block at 0x%08x\n",
199 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
200 /* Factory marked bad or worn out ? */
202 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
204 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
205 mtd->ecc_stats.badblocks++;
215 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
216 * @mtd: MTD device structure
217 * @buf: temporary buffer
218 * @td: descriptor for the bad block table
219 * @chip: read the table for a specific chip, -1 read all chips.
220 * Applies only if NAND_BBT_PERCHIP option is set
222 * Read the bad block table for all chips starting at a given page
223 * We assume that the bbt bits are in consecutive order.
225 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
227 struct nand_chip *this = mtd->priv;
231 bits = td->options & NAND_BBT_NRBITS_MSK;
232 if (td->options & NAND_BBT_PERCHIP) {
234 for (i = 0; i < this->numchips; i++) {
235 if (chip == -1 || chip == i)
236 res = read_bbt (mtd, buf, td->pages[i], this->chipsize >> this->bbt_erase_shift, bits, offs, td->reserved_block_code);
239 offs += this->chipsize >> (this->bbt_erase_shift + 2);
242 res = read_bbt (mtd, buf, td->pages[0], mtd->size >> this->bbt_erase_shift, bits, 0, td->reserved_block_code);
250 * Scan read raw data from flash
252 static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
255 struct mtd_oob_ops ops;
257 ops.mode = MTD_OOB_RAW;
259 ops.ooblen = mtd->oobsize;
264 return mtd->read_oob(mtd, offs, &ops);
268 * Scan write data with oob to flash
270 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
271 uint8_t *buf, uint8_t *oob)
273 struct mtd_oob_ops ops;
275 ops.mode = MTD_OOB_PLACE;
277 ops.ooblen = mtd->oobsize;
282 return mtd->write_oob(mtd, offs, &ops);
286 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
287 * @mtd: MTD device structure
288 * @buf: temporary buffer
289 * @td: descriptor for the bad block table
290 * @md: descriptor for the bad block table mirror
292 * Read the bad block table(s) for all chips starting at a given page
293 * We assume that the bbt bits are in consecutive order.
296 static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
297 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
299 struct nand_chip *this = mtd->priv;
301 /* Read the primary version, if available */
302 if (td->options & NAND_BBT_VERSION) {
303 scan_read_raw(mtd, buf, td->pages[0] << this->page_shift,
305 td->version[0] = buf[mtd->writesize + td->veroffs];
306 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
307 td->pages[0], td->version[0]);
310 /* Read the mirror version, if available */
311 if (md && (md->options & NAND_BBT_VERSION)) {
312 scan_read_raw(mtd, buf, md->pages[0] << this->page_shift,
314 md->version[0] = buf[mtd->writesize + md->veroffs];
315 printk(KERN_DEBUG "Bad block table at page %d, version 0x%02X\n",
316 md->pages[0], md->version[0]);
322 * Scan a given block full
324 static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
325 loff_t offs, uint8_t *buf, size_t readlen,
326 int scanlen, int len)
330 ret = scan_read_raw(mtd, buf, offs, readlen);
334 for (j = 0; j < len; j++, buf += scanlen) {
335 if (check_pattern(buf, scanlen, mtd->writesize, bd))
342 * Scan a given block partially
344 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
345 loff_t offs, uint8_t *buf, int len)
347 struct mtd_oob_ops ops;
350 ops.ooblen = mtd->oobsize;
354 ops.mode = MTD_OOB_PLACE;
356 for (j = 0; j < len; j++) {
358 * Read the full oob until read_oob is fixed to
359 * handle single byte reads for 16 bit
362 ret = mtd->read_oob(mtd, offs, &ops);
366 if (check_short_pattern(buf, bd))
369 offs += mtd->writesize;
375 * create_bbt - [GENERIC] Create a bad block table by scanning the device
376 * @mtd: MTD device structure
377 * @buf: temporary buffer
378 * @bd: descriptor for the good/bad block search pattern
379 * @chip: create the table for a specific chip, -1 read all chips.
380 * Applies only if NAND_BBT_PERCHIP option is set
382 * Create a bad block table by scanning the device
383 * for the given good/bad block identify pattern
385 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
386 struct nand_bbt_descr *bd, int chip)
388 struct nand_chip *this = mtd->priv;
389 int i, numblocks, len, scanlen;
394 printk(KERN_INFO "Scanning device for bad blocks\n");
396 if (bd->options & NAND_BBT_SCANALLPAGES)
397 len = 1 << (this->bbt_erase_shift - this->page_shift);
399 if (bd->options & NAND_BBT_SCAN2NDPAGE)
405 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
406 /* We need only read few bytes from the OOB area */
410 /* Full page content should be read */
411 scanlen = mtd->writesize + mtd->oobsize;
412 readlen = len * mtd->writesize;
416 /* Note that numblocks is 2 * (real numblocks) here, see i+=2
417 * below as it makes shifting and masking less painful */
418 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
422 if (chip >= this->numchips) {
423 printk(KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
424 chip + 1, this->numchips);
427 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
428 startblock = chip * numblocks;
429 numblocks += startblock;
430 from = startblock << (this->bbt_erase_shift - 1);
433 for (i = startblock; i < numblocks;) {
436 if (bd->options & NAND_BBT_SCANALLPAGES)
437 ret = scan_block_full(mtd, bd, from, buf, readlen,
440 ret = scan_block_fast(mtd, bd, from, buf, len);
446 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
447 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
448 i >> 1, (unsigned int)from);
449 mtd->ecc_stats.badblocks++;
453 from += (1 << this->bbt_erase_shift);
459 * search_bbt - [GENERIC] scan the device for a specific bad block table
460 * @mtd: MTD device structure
461 * @buf: temporary buffer
462 * @td: descriptor for the bad block table
464 * Read the bad block table by searching for a given ident pattern.
465 * Search is preformed either from the beginning up or from the end of
466 * the device downwards. The search starts always at the start of a
468 * If the option NAND_BBT_PERCHIP is given, each chip is searched
469 * for a bbt, which contains the bad block information of this chip.
470 * This is necessary to provide support for certain DOC devices.
472 * The bbt ident pattern resides in the oob area of the first page
475 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
477 struct nand_chip *this = mtd->priv;
479 int bits, startblock, block, dir;
480 int scanlen = mtd->writesize + mtd->oobsize;
482 int blocktopage = this->bbt_erase_shift - this->page_shift;
484 /* Search direction top -> down ? */
485 if (td->options & NAND_BBT_LASTBLOCK) {
486 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
493 /* Do we have a bbt per chip ? */
494 if (td->options & NAND_BBT_PERCHIP) {
495 chips = this->numchips;
496 bbtblocks = this->chipsize >> this->bbt_erase_shift;
497 startblock &= bbtblocks - 1;
500 bbtblocks = mtd->size >> this->bbt_erase_shift;
503 /* Number of bits for each erase block in the bbt */
504 bits = td->options & NAND_BBT_NRBITS_MSK;
506 for (i = 0; i < chips; i++) {
507 /* Reset version information */
510 /* Scan the maximum number of blocks */
511 for (block = 0; block < td->maxblocks; block++) {
513 int actblock = startblock + dir * block;
514 loff_t offs = actblock << this->bbt_erase_shift;
516 /* Read first page */
517 scan_read_raw(mtd, buf, offs, mtd->writesize);
518 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
519 td->pages[i] = actblock << blocktopage;
520 if (td->options & NAND_BBT_VERSION) {
521 td->version[i] = buf[mtd->writesize + td->veroffs];
526 startblock += this->chipsize >> this->bbt_erase_shift;
528 /* Check, if we found a bbt for each requested chip */
529 for (i = 0; i < chips; i++) {
530 if (td->pages[i] == -1)
531 printk(KERN_WARNING "Bad block table not found for chip %d\n", i);
533 printk(KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i],
540 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
541 * @mtd: MTD device structure
542 * @buf: temporary buffer
543 * @td: descriptor for the bad block table
544 * @md: descriptor for the bad block table mirror
546 * Search and read the bad block table(s)
548 static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
550 /* Search the primary table */
551 search_bbt(mtd, buf, td);
553 /* Search the mirror table */
555 search_bbt(mtd, buf, md);
557 /* Force result check */
562 * write_bbt - [GENERIC] (Re)write the bad block table
564 * @mtd: MTD device structure
565 * @buf: temporary buffer
566 * @td: descriptor for the bad block table
567 * @md: descriptor for the bad block table mirror
568 * @chipsel: selector for a specific chip, -1 for all
570 * (Re)write the bad block table
573 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
574 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
577 struct nand_chip *this = mtd->priv;
578 struct erase_info einfo;
579 int i, j, res, chip = 0;
580 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
581 int nrchips, bbtoffs, pageoffs, ooboffs;
583 uint8_t rcode = td->reserved_block_code;
584 size_t retlen, len = 0;
586 struct mtd_oob_ops ops;
588 ops.ooblen = mtd->oobsize;
591 ops.mode = MTD_OOB_PLACE;
595 /* Write bad block table per chip rather than per device ? */
596 if (td->options & NAND_BBT_PERCHIP) {
597 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
598 /* Full device write or specific chip ? */
600 nrchips = this->numchips;
602 nrchips = chipsel + 1;
606 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
610 /* Loop through the chips */
611 for (; chip < nrchips; chip++) {
613 /* There was already a version of the table, reuse the page
614 * This applies for absolute placement too, as we have the
615 * page nr. in td->pages.
617 if (td->pages[chip] != -1) {
618 page = td->pages[chip];
622 /* Automatic placement of the bad block table */
623 /* Search direction top -> down ? */
624 if (td->options & NAND_BBT_LASTBLOCK) {
625 startblock = numblocks * (chip + 1) - 1;
628 startblock = chip * numblocks;
632 for (i = 0; i < td->maxblocks; i++) {
633 int block = startblock + dir * i;
634 /* Check, if the block is bad */
635 switch ((this->bbt[block >> 2] >>
636 (2 * (block & 0x03))) & 0x03) {
642 (this->bbt_erase_shift - this->page_shift);
643 /* Check, if the block is used by the mirror table */
644 if (!md || md->pages[chip] != page)
647 printk(KERN_ERR "No space left to write bad block table\n");
651 /* Set up shift count and masks for the flash table */
652 bits = td->options & NAND_BBT_NRBITS_MSK;
655 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
658 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
661 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
664 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
667 default: return -EINVAL;
670 bbtoffs = chip * (numblocks >> 2);
672 to = ((loff_t) page) << this->page_shift;
674 /* Must we save the block contents ? */
675 if (td->options & NAND_BBT_SAVECONTENT) {
676 /* Make it block aligned */
677 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
678 len = 1 << this->bbt_erase_shift;
679 res = mtd->read(mtd, to, len, &retlen, buf);
682 printk(KERN_INFO "nand_bbt: Error "
683 "reading block for writing "
684 "the bad block table\n");
687 printk(KERN_WARNING "nand_bbt: ECC error "
688 "while reading block for writing "
689 "bad block table\n");
692 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
693 ops.oobbuf = &buf[len];
694 res = mtd->read_oob(mtd, to + mtd->writesize, &ops);
695 if (res < 0 || ops.oobretlen != ops.ooblen)
698 /* Calc the byte offset in the buffer */
699 pageoffs = page - (int)(to >> this->page_shift);
700 offs = pageoffs << this->page_shift;
701 /* Preset the bbt area with 0xff */
702 memset(&buf[offs], 0xff, (size_t) (numblocks >> sft));
703 ooboffs = len + (pageoffs * mtd->oobsize);
707 len = (size_t) (numblocks >> sft);
708 /* Make it page aligned ! */
709 len = (len + (mtd->writesize - 1)) &
710 ~(mtd->writesize - 1);
711 /* Preset the buffer with 0xff */
712 memset(buf, 0xff, len +
713 (len >> this->page_shift)* mtd->oobsize);
716 /* Pattern is located in oob area of first page */
717 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
720 if (td->options & NAND_BBT_VERSION)
721 buf[ooboffs + td->veroffs] = td->version[chip];
723 /* walk through the memory table */
724 for (i = 0; i < numblocks;) {
726 dat = this->bbt[bbtoffs + (i >> 2)];
727 for (j = 0; j < 4; j++, i++) {
728 int sftcnt = (i << (3 - sft)) & sftmsk;
729 /* Do not store the reserved bbt blocks ! */
730 buf[offs + (i >> sft)] &=
731 ~(msk[dat & 0x03] << sftcnt);
736 memset(&einfo, 0, sizeof(einfo));
738 einfo.addr = (unsigned long)to;
739 einfo.len = 1 << this->bbt_erase_shift;
740 res = nand_erase_nand(mtd, &einfo, 1);
744 res = scan_write_bbt(mtd, to, len, buf, &buf[len]);
748 printk(KERN_DEBUG "Bad block table written to 0x%08x, version "
749 "0x%02X\n", (unsigned int)to, td->version[chip]);
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, block << (this->bbt_erase_shift - 1));
933 if (td->options & NAND_BBT_LASTBLOCK)
934 block = ((i + 1) * nrblocks) - td->maxblocks;
936 block = i * nrblocks;
938 for (j = 0; j < td->maxblocks; j++) {
939 oldval = this->bbt[(block >> 3)];
940 newval = oldval | (0x2 << (block & 0x06));
941 this->bbt[(block >> 3)] = newval;
942 if (oldval != newval)
946 /* If we want reserved blocks to be recorded to flash, and some
947 new ones have been marked, then we need to update the stored
948 bbts. This should only happen once. */
949 if (update && td->reserved_block_code)
950 nand_update_bbt(mtd, (block - 2) << (this->bbt_erase_shift - 1));
955 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
956 * @mtd: MTD device structure
957 * @bd: descriptor for the good/bad block search pattern
959 * The function checks, if a bad block table(s) is/are already
960 * available. If not it scans the device for manufacturer
961 * marked good / bad blocks and writes the bad block table(s) to
962 * the selected place.
964 * The bad block table memory is allocated here. It must be freed
965 * by calling the nand_free_bbt function.
968 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
970 struct nand_chip *this = mtd->priv;
973 struct nand_bbt_descr *td = this->bbt_td;
974 struct nand_bbt_descr *md = this->bbt_md;
976 len = mtd->size >> (this->bbt_erase_shift + 2);
977 /* Allocate memory (2bit per block) and clear the memory bad block table */
978 this->bbt = kzalloc(len, GFP_KERNEL);
980 printk(KERN_ERR "nand_scan_bbt: Out of memory\n");
984 /* If no primary table decriptor is given, scan the device
985 * to build a memory based bad block table
988 if ((res = nand_memory_bbt(mtd, bd))) {
989 printk(KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
996 /* Allocate a temporary buffer for one eraseblock incl. oob */
997 len = (1 << this->bbt_erase_shift);
998 len += (len >> this->page_shift) * mtd->oobsize;
1001 printk(KERN_ERR "nand_bbt: Out of memory\n");
1007 /* Is the bbt at a given page ? */
1008 if (td->options & NAND_BBT_ABSPAGE) {
1009 res = read_abs_bbts(mtd, buf, td, md);
1011 /* Search the bad block table using a pattern in oob */
1012 res = search_read_bbts(mtd, buf, td, md);
1016 res = check_create(mtd, buf, bd);
1018 /* Prevent the bbt regions from erasing / writing */
1019 mark_bbt_region(mtd, td);
1021 mark_bbt_region(mtd, md);
1028 * nand_update_bbt - [NAND Interface] update bad block table(s)
1029 * @mtd: MTD device structure
1030 * @offs: the offset of the newly marked block
1032 * The function updates the bad block table(s)
1034 int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1036 struct nand_chip *this = mtd->priv;
1037 int len, res = 0, writeops = 0;
1040 struct nand_bbt_descr *td = this->bbt_td;
1041 struct nand_bbt_descr *md = this->bbt_md;
1043 if (!this->bbt || !td)
1046 len = mtd->size >> (this->bbt_erase_shift + 2);
1047 /* Allocate a temporary buffer for one eraseblock incl. oob */
1048 len = (1 << this->bbt_erase_shift);
1049 len += (len >> this->page_shift) * mtd->oobsize;
1050 buf = kmalloc(len, GFP_KERNEL);
1052 printk(KERN_ERR "nand_update_bbt: Out of memory\n");
1056 writeops = md != NULL ? 0x03 : 0x01;
1058 /* Do we have a bbt per chip ? */
1059 if (td->options & NAND_BBT_PERCHIP) {
1060 chip = (int)(offs >> this->chip_shift);
1067 td->version[chip]++;
1069 md->version[chip]++;
1071 /* Write the bad block table to the device ? */
1072 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1073 res = write_bbt(mtd, buf, td, md, chipsel);
1077 /* Write the mirror bad block table to the device ? */
1078 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1079 res = write_bbt(mtd, buf, md, td, chipsel);
1087 /* Define some generic bad / good block scan pattern which are used
1088 * while scanning a device for factory marked good / bad blocks. */
1089 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1091 static struct nand_bbt_descr smallpage_memorybased = {
1092 .options = NAND_BBT_SCAN2NDPAGE,
1095 .pattern = scan_ff_pattern
1098 static struct nand_bbt_descr largepage_memorybased = {
1102 .pattern = scan_ff_pattern
1105 static struct nand_bbt_descr smallpage_flashbased = {
1106 .options = NAND_BBT_SCAN2NDPAGE,
1109 .pattern = scan_ff_pattern
1112 static struct nand_bbt_descr largepage_flashbased = {
1113 .options = NAND_BBT_SCAN2NDPAGE,
1116 .pattern = scan_ff_pattern
1119 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1121 static struct nand_bbt_descr agand_flashbased = {
1122 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1125 .pattern = scan_agand_pattern
1128 /* Generic flash bbt decriptors
1130 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1131 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1133 static struct nand_bbt_descr bbt_main_descr = {
1134 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1135 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1140 .pattern = bbt_pattern
1143 static struct nand_bbt_descr bbt_mirror_descr = {
1144 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1145 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1150 .pattern = mirror_pattern
1154 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1155 * @mtd: MTD device structure
1157 * This function selects the default bad block table
1158 * support for the device and calls the nand_scan_bbt function
1161 int nand_default_bbt(struct mtd_info *mtd)
1163 struct nand_chip *this = mtd->priv;
1165 /* Default for AG-AND. We must use a flash based
1166 * bad block table as the devices have factory marked
1167 * _good_ blocks. Erasing those blocks leads to loss
1168 * of the good / bad information, so we _must_ store
1169 * this information in a good / bad table during
1172 if (this->options & NAND_IS_AND) {
1173 /* Use the default pattern descriptors */
1174 if (!this->bbt_td) {
1175 this->bbt_td = &bbt_main_descr;
1176 this->bbt_md = &bbt_mirror_descr;
1178 this->options |= NAND_USE_FLASH_BBT;
1179 return nand_scan_bbt(mtd, &agand_flashbased);
1182 /* Is a flash based bad block table requested ? */
1183 if (this->options & NAND_USE_FLASH_BBT) {
1184 /* Use the default pattern descriptors */
1185 if (!this->bbt_td) {
1186 this->bbt_td = &bbt_main_descr;
1187 this->bbt_md = &bbt_mirror_descr;
1189 if (!this->badblock_pattern) {
1190 this->badblock_pattern = (mtd->writesize > 512) ? &largepage_flashbased : &smallpage_flashbased;
1193 this->bbt_td = NULL;
1194 this->bbt_md = NULL;
1195 if (!this->badblock_pattern) {
1196 this->badblock_pattern = (mtd->writesize > 512) ?
1197 &largepage_memorybased : &smallpage_memorybased;
1200 return nand_scan_bbt(mtd, this->badblock_pattern);
1204 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1205 * @mtd: MTD device structure
1206 * @offs: offset in the device
1207 * @allowbbt: allow access to bad block table region
1210 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1212 struct nand_chip *this = mtd->priv;
1216 /* Get block number * 2 */
1217 block = (int)(offs >> (this->bbt_erase_shift - 1));
1218 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1220 MTDDEBUG (MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: "
1221 "(block %d) 0x%02x\n", (unsigned int)offs, res, block >> 1);
1229 return allowbbt ? 0 : 1;
1234 /* XXX U-BOOT XXX */
1236 EXPORT_SYMBOL(nand_scan_bbt);
1237 EXPORT_SYMBOL(nand_default_bbt);