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 1.31 2005/02/16 17:09:36 dedekind 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24 * If one of the bbt's is out of date or does not exist it is (re)created.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 neccecary 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>
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 if (td->options & NAND_BBT_SCANEMPTY) {
84 end = paglen + td->offs;
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 * read_bbt - [GENERIC] Read the bad block table starting from page
111 * @mtd: MTD device structure
112 * @buf: temporary buffer
113 * @page: the starting page
114 * @num: the number of bbt descriptors to read
115 * @bits: number of bits per block
116 * @offs: offset in the memory table
117 * @reserved_block_code: Pattern to identify reserved blocks
119 * Read the bad block table starting from page.
122 static int read_bbt (struct mtd_info *mtd, uint8_t *buf, int page, int num,
123 int bits, int offs, int reserved_block_code)
125 int res, i, j, act = 0;
126 struct nand_chip *this = mtd->priv;
127 size_t retlen, len, totlen;
129 uint8_t msk = (uint8_t) ((1 << bits) - 1);
131 totlen = (num * bits) >> 3;
132 from = ((loff_t)page) << this->page_shift;
135 len = min (totlen, (size_t) (1 << this->bbt_erase_shift));
136 res = mtd->read_ecc (mtd, from, len, &retlen, buf, NULL, this->autooob);
139 printk (KERN_INFO "nand_bbt: Error reading bad block table\n");
142 printk (KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
146 for (i = 0; i < len; i++) {
147 uint8_t dat = buf[i];
148 for (j = 0; j < 8; j += bits, act += 2) {
149 uint8_t tmp = (dat >> j) & msk;
152 if (reserved_block_code &&
153 (tmp == reserved_block_code)) {
154 printk (KERN_DEBUG "nand_read_bbt: Reserved block at 0x%08x\n",
155 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
156 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
159 /* Leave it for now, if its matured we can move this
160 * message to MTD_DEBUG_LEVEL0 */
161 printk (KERN_DEBUG "nand_read_bbt: Bad block at 0x%08x\n",
162 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
163 /* Factory marked bad or worn out ? */
165 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
167 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
177 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
178 * @mtd: MTD device structure
179 * @buf: temporary buffer
180 * @td: descriptor for the bad block table
181 * @chip: read the table for a specific chip, -1 read all chips.
182 * Applies only if NAND_BBT_PERCHIP option is set
184 * Read the bad block table for all chips starting at a given page
185 * We assume that the bbt bits are in consecutive order.
187 static int read_abs_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
189 struct nand_chip *this = mtd->priv;
193 bits = td->options & NAND_BBT_NRBITS_MSK;
194 if (td->options & NAND_BBT_PERCHIP) {
196 for (i = 0; i < this->numchips; i++) {
197 if (chip == -1 || chip == i)
198 res = read_bbt (mtd, buf, td->pages[i], this->chipsize >> this->bbt_erase_shift, bits, offs, td->reserved_block_code);
201 offs += this->chipsize >> (this->bbt_erase_shift + 2);
204 res = read_bbt (mtd, buf, td->pages[0], mtd->size >> this->bbt_erase_shift, bits, 0, td->reserved_block_code);
212 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
213 * @mtd: MTD device structure
214 * @buf: temporary buffer
215 * @td: descriptor for the bad block table
216 * @md: descriptor for the bad block table mirror
218 * Read the bad block table(s) for all chips starting at a given page
219 * We assume that the bbt bits are in consecutive order.
222 static int read_abs_bbts (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td,
223 struct nand_bbt_descr *md)
225 struct nand_chip *this = mtd->priv;
227 /* Read the primary version, if available */
228 if (td->options & NAND_BBT_VERSION) {
229 nand_read_raw (mtd, buf, td->pages[0] << this->page_shift, mtd->oobblock, mtd->oobsize);
230 td->version[0] = buf[mtd->oobblock + td->veroffs];
231 printk (KERN_DEBUG "Bad block table at page %d, version 0x%02X\n", td->pages[0], td->version[0]);
234 /* Read the mirror version, if available */
235 if (md && (md->options & NAND_BBT_VERSION)) {
236 nand_read_raw (mtd, buf, md->pages[0] << this->page_shift, mtd->oobblock, mtd->oobsize);
237 md->version[0] = buf[mtd->oobblock + md->veroffs];
238 printk (KERN_DEBUG "Bad block table at page %d, version 0x%02X\n", md->pages[0], md->version[0]);
245 * create_bbt - [GENERIC] Create a bad block table by scanning the device
246 * @mtd: MTD device structure
247 * @buf: temporary buffer
248 * @bd: descriptor for the good/bad block search pattern
249 * @chip: create the table for a specific chip, -1 read all chips.
250 * Applies only if NAND_BBT_PERCHIP option is set
252 * Create a bad block table by scanning the device
253 * for the given good/bad block identify pattern
255 static int create_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
257 struct nand_chip *this = mtd->priv;
258 int i, j, numblocks, len, scanlen;
261 size_t readlen, ooblen;
263 printk (KERN_INFO "Scanning device for bad blocks\n");
265 if (bd->options & NAND_BBT_SCANALLPAGES)
266 len = 1 << (this->bbt_erase_shift - this->page_shift);
268 if (bd->options & NAND_BBT_SCAN2NDPAGE)
274 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
275 /* We need only read few bytes from the OOB area */
276 scanlen = ooblen = 0;
279 /* Full page content should be read */
280 scanlen = mtd->oobblock + mtd->oobsize;
281 readlen = len * mtd->oobblock;
282 ooblen = len * mtd->oobsize;
286 /* Note that numblocks is 2 * (real numblocks) here, see i+=2 below as it
287 * makes shifting and masking less painful */
288 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
292 if (chip >= this->numchips) {
293 printk (KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
294 chip + 1, this->numchips);
297 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
298 startblock = chip * numblocks;
299 numblocks += startblock;
300 from = startblock << (this->bbt_erase_shift - 1);
303 for (i = startblock; i < numblocks;) {
306 if (bd->options & NAND_BBT_SCANEMPTY)
307 if ((ret = nand_read_raw (mtd, buf, from, readlen, ooblen)))
310 for (j = 0; j < len; j++) {
311 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
314 /* No need to read pages fully, just read required OOB bytes */
315 ret = mtd->read_oob(mtd, from + j * mtd->oobblock + bd->offs,
316 readlen, &retlen, &buf[0]);
320 if (check_pattern (&buf[j * scanlen], scanlen, mtd->oobblock, bd)) {
321 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
322 printk (KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
323 i >> 1, (unsigned int) from);
328 from += (1 << this->bbt_erase_shift);
335 * search_bbt - [GENERIC] scan the device for a specific bad block table
336 * @mtd: MTD device structure
337 * @buf: temporary buffer
338 * @td: descriptor for the bad block table
340 * Read the bad block table by searching for a given ident pattern.
341 * Search is preformed either from the beginning up or from the end of
342 * the device downwards. The search starts always at the start of a
344 * If the option NAND_BBT_PERCHIP is given, each chip is searched
345 * for a bbt, which contains the bad block information of this chip.
346 * This is neccecary to provide support for certain DOC devices.
348 * The bbt ident pattern resides in the oob area of the first page
351 static int search_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
353 struct nand_chip *this = mtd->priv;
355 int bits, startblock, block, dir;
356 int scanlen = mtd->oobblock + mtd->oobsize;
359 /* Search direction top -> down ? */
360 if (td->options & NAND_BBT_LASTBLOCK) {
361 startblock = (mtd->size >> this->bbt_erase_shift) -1;
368 /* Do we have a bbt per chip ? */
369 if (td->options & NAND_BBT_PERCHIP) {
370 chips = this->numchips;
371 bbtblocks = this->chipsize >> this->bbt_erase_shift;
372 startblock &= bbtblocks - 1;
375 bbtblocks = mtd->size >> this->bbt_erase_shift;
378 /* Number of bits for each erase block in the bbt */
379 bits = td->options & NAND_BBT_NRBITS_MSK;
381 for (i = 0; i < chips; i++) {
382 /* Reset version information */
385 /* Scan the maximum number of blocks */
386 for (block = 0; block < td->maxblocks; block++) {
387 int actblock = startblock + dir * block;
388 /* Read first page */
389 nand_read_raw (mtd, buf, actblock << this->bbt_erase_shift, mtd->oobblock, mtd->oobsize);
390 if (!check_pattern(buf, scanlen, mtd->oobblock, td)) {
391 td->pages[i] = actblock << (this->bbt_erase_shift - this->page_shift);
392 if (td->options & NAND_BBT_VERSION) {
393 td->version[i] = buf[mtd->oobblock + td->veroffs];
398 startblock += this->chipsize >> this->bbt_erase_shift;
400 /* Check, if we found a bbt for each requested chip */
401 for (i = 0; i < chips; i++) {
402 if (td->pages[i] == -1)
403 printk (KERN_WARNING "Bad block table not found for chip %d\n", i);
405 printk (KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i], td->version[i]);
411 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
412 * @mtd: MTD device structure
413 * @buf: temporary buffer
414 * @td: descriptor for the bad block table
415 * @md: descriptor for the bad block table mirror
417 * Search and read the bad block table(s)
419 static int search_read_bbts (struct mtd_info *mtd, uint8_t *buf,
420 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
422 /* Search the primary table */
423 search_bbt (mtd, buf, td);
425 /* Search the mirror table */
427 search_bbt (mtd, buf, md);
429 /* Force result check */
435 * write_bbt - [GENERIC] (Re)write the bad block table
437 * @mtd: MTD device structure
438 * @buf: temporary buffer
439 * @td: descriptor for the bad block table
440 * @md: descriptor for the bad block table mirror
441 * @chipsel: selector for a specific chip, -1 for all
443 * (Re)write the bad block table
446 static int write_bbt (struct mtd_info *mtd, uint8_t *buf,
447 struct nand_bbt_descr *td, struct nand_bbt_descr *md, int chipsel)
449 struct nand_chip *this = mtd->priv;
450 struct nand_oobinfo oobinfo;
451 struct erase_info einfo;
452 int i, j, res, chip = 0;
453 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
454 int nrchips, bbtoffs, pageoffs;
456 uint8_t rcode = td->reserved_block_code;
457 size_t retlen, len = 0;
462 /* Write bad block table per chip rather than per device ? */
463 if (td->options & NAND_BBT_PERCHIP) {
464 numblocks = (int) (this->chipsize >> this->bbt_erase_shift);
465 /* Full device write or specific chip ? */
467 nrchips = this->numchips;
469 nrchips = chipsel + 1;
473 numblocks = (int) (mtd->size >> this->bbt_erase_shift);
477 /* Loop through the chips */
478 for (; chip < nrchips; chip++) {
480 /* There was already a version of the table, reuse the page
481 * This applies for absolute placement too, as we have the
482 * page nr. in td->pages.
484 if (td->pages[chip] != -1) {
485 page = td->pages[chip];
489 /* Automatic placement of the bad block table */
490 /* Search direction top -> down ? */
491 if (td->options & NAND_BBT_LASTBLOCK) {
492 startblock = numblocks * (chip + 1) - 1;
495 startblock = chip * numblocks;
499 for (i = 0; i < td->maxblocks; i++) {
500 int block = startblock + dir * i;
501 /* Check, if the block is bad */
502 switch ((this->bbt[block >> 2] >> (2 * (block & 0x03))) & 0x03) {
507 page = block << (this->bbt_erase_shift - this->page_shift);
508 /* Check, if the block is used by the mirror table */
509 if (!md || md->pages[chip] != page)
512 printk (KERN_ERR "No space left to write bad block table\n");
516 /* Set up shift count and masks for the flash table */
517 bits = td->options & NAND_BBT_NRBITS_MSK;
519 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01; msk[2] = ~rcode; msk[3] = 0x01; break;
520 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01; msk[2] = ~rcode; msk[3] = 0x03; break;
521 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C; msk[2] = ~rcode; msk[3] = 0x0f; break;
522 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F; msk[2] = ~rcode; msk[3] = 0xff; break;
523 default: return -EINVAL;
526 bbtoffs = chip * (numblocks >> 2);
528 to = ((loff_t) page) << this->page_shift;
530 memcpy (&oobinfo, this->autooob, sizeof(oobinfo));
531 oobinfo.useecc = MTD_NANDECC_PLACEONLY;
533 /* Must we save the block contents ? */
534 if (td->options & NAND_BBT_SAVECONTENT) {
535 /* Make it block aligned */
536 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
537 len = 1 << this->bbt_erase_shift;
538 res = mtd->read_ecc (mtd, to, len, &retlen, buf, &buf[len], &oobinfo);
541 printk (KERN_INFO "nand_bbt: Error reading block for writing the bad block table\n");
544 printk (KERN_WARNING "nand_bbt: ECC error while reading block for writing bad block table\n");
546 /* Calc the byte offset in the buffer */
547 pageoffs = page - (int)(to >> this->page_shift);
548 offs = pageoffs << this->page_shift;
549 /* Preset the bbt area with 0xff */
550 memset (&buf[offs], 0xff, (size_t)(numblocks >> sft));
551 /* Preset the bbt's oob area with 0xff */
552 memset (&buf[len + pageoffs * mtd->oobsize], 0xff,
553 ((len >> this->page_shift) - pageoffs) * mtd->oobsize);
554 if (td->options & NAND_BBT_VERSION) {
555 buf[len + (pageoffs * mtd->oobsize) + td->veroffs] = td->version[chip];
559 len = (size_t) (numblocks >> sft);
560 /* Make it page aligned ! */
561 len = (len + (mtd->oobblock-1)) & ~(mtd->oobblock-1);
562 /* Preset the buffer with 0xff */
563 memset (buf, 0xff, len + (len >> this->page_shift) * mtd->oobsize);
565 /* Pattern is located in oob area of first page */
566 memcpy (&buf[len + td->offs], td->pattern, td->len);
567 if (td->options & NAND_BBT_VERSION) {
568 buf[len + td->veroffs] = td->version[chip];
572 /* walk through the memory table */
573 for (i = 0; i < numblocks; ) {
575 dat = this->bbt[bbtoffs + (i >> 2)];
576 for (j = 0; j < 4; j++ , i++) {
577 int sftcnt = (i << (3 - sft)) & sftmsk;
578 /* Do not store the reserved bbt blocks ! */
579 buf[offs + (i >> sft)] &= ~(msk[dat & 0x03] << sftcnt);
584 memset (&einfo, 0, sizeof (einfo));
586 einfo.addr = (unsigned long) to;
587 einfo.len = 1 << this->bbt_erase_shift;
588 res = nand_erase_nand (mtd, &einfo, 1);
590 printk (KERN_WARNING "nand_bbt: Error during block erase: %d\n", res);
594 res = mtd->write_ecc (mtd, to, len, &retlen, buf, &buf[len], &oobinfo);
596 printk (KERN_WARNING "nand_bbt: Error while writing bad block table %d\n", res);
599 printk (KERN_DEBUG "Bad block table written to 0x%08x, version 0x%02X\n",
600 (unsigned int) to, td->version[chip]);
602 /* Mark it as used */
603 td->pages[chip] = page;
609 * nand_memory_bbt - [GENERIC] create a memory based bad block table
610 * @mtd: MTD device structure
611 * @bd: descriptor for the good/bad block search pattern
613 * The function creates a memory based bbt by scanning the device
614 * for manufacturer / software marked good / bad blocks
616 static inline int nand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
618 struct nand_chip *this = mtd->priv;
620 bd->options &= ~NAND_BBT_SCANEMPTY;
621 return create_bbt (mtd, this->data_buf, bd, -1);
625 * check_create - [GENERIC] create and write bbt(s) if neccecary
626 * @mtd: MTD device structure
627 * @buf: temporary buffer
628 * @bd: descriptor for the good/bad block search pattern
630 * The function checks the results of the previous call to read_bbt
631 * and creates / updates the bbt(s) if neccecary
632 * Creation is neccecary if no bbt was found for the chip/device
633 * Update is neccecary if one of the tables is missing or the
634 * version nr. of one table is less than the other
636 static int check_create (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
638 int i, chips, writeops, chipsel, res;
639 struct nand_chip *this = mtd->priv;
640 struct nand_bbt_descr *td = this->bbt_td;
641 struct nand_bbt_descr *md = this->bbt_md;
642 struct nand_bbt_descr *rd, *rd2;
644 /* Do we have a bbt per chip ? */
645 if (td->options & NAND_BBT_PERCHIP)
646 chips = this->numchips;
650 for (i = 0; i < chips; i++) {
654 /* Per chip or per device ? */
655 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
656 /* Mirrored table avilable ? */
658 if (td->pages[i] == -1 && md->pages[i] == -1) {
663 if (td->pages[i] == -1) {
665 td->version[i] = md->version[i];
670 if (md->pages[i] == -1) {
672 md->version[i] = td->version[i];
677 if (td->version[i] == md->version[i]) {
679 if (!(td->options & NAND_BBT_VERSION))
684 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
686 md->version[i] = td->version[i];
690 td->version[i] = md->version[i];
697 if (td->pages[i] == -1) {
705 /* Create the bad block table by scanning the device ? */
706 if (!(td->options & NAND_BBT_CREATE))
709 /* Create the table in memory by scanning the chip(s) */
710 create_bbt (mtd, buf, bd, chipsel);
716 /* read back first ? */
718 read_abs_bbt (mtd, buf, rd, chipsel);
719 /* If they weren't versioned, read both. */
721 read_abs_bbt (mtd, buf, rd2, chipsel);
723 /* Write the bad block table to the device ? */
724 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
725 res = write_bbt (mtd, buf, td, md, chipsel);
730 /* Write the mirror bad block table to the device ? */
731 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
732 res = write_bbt (mtd, buf, md, td, chipsel);
741 * mark_bbt_regions - [GENERIC] mark the bad block table regions
742 * @mtd: MTD device structure
743 * @td: bad block table descriptor
745 * The bad block table regions are marked as "bad" to prevent
746 * accidental erasures / writes. The regions are identified by
749 static void mark_bbt_region (struct mtd_info *mtd, struct nand_bbt_descr *td)
751 struct nand_chip *this = mtd->priv;
752 int i, j, chips, block, nrblocks, update;
753 uint8_t oldval, newval;
755 /* Do we have a bbt per chip ? */
756 if (td->options & NAND_BBT_PERCHIP) {
757 chips = this->numchips;
758 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
761 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
764 for (i = 0; i < chips; i++) {
765 if ((td->options & NAND_BBT_ABSPAGE) ||
766 !(td->options & NAND_BBT_WRITE)) {
767 if (td->pages[i] == -1) continue;
768 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
770 oldval = this->bbt[(block >> 3)];
771 newval = oldval | (0x2 << (block & 0x06));
772 this->bbt[(block >> 3)] = newval;
773 if ((oldval != newval) && td->reserved_block_code)
774 nand_update_bbt(mtd, block << (this->bbt_erase_shift - 1));
778 if (td->options & NAND_BBT_LASTBLOCK)
779 block = ((i + 1) * nrblocks) - td->maxblocks;
781 block = i * nrblocks;
783 for (j = 0; j < td->maxblocks; j++) {
784 oldval = this->bbt[(block >> 3)];
785 newval = oldval | (0x2 << (block & 0x06));
786 this->bbt[(block >> 3)] = newval;
787 if (oldval != newval) update = 1;
790 /* If we want reserved blocks to be recorded to flash, and some
791 new ones have been marked, then we need to update the stored
792 bbts. This should only happen once. */
793 if (update && td->reserved_block_code)
794 nand_update_bbt(mtd, (block - 2) << (this->bbt_erase_shift - 1));
799 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
800 * @mtd: MTD device structure
801 * @bd: descriptor for the good/bad block search pattern
803 * The function checks, if a bad block table(s) is/are already
804 * available. If not it scans the device for manufacturer
805 * marked good / bad blocks and writes the bad block table(s) to
806 * the selected place.
808 * The bad block table memory is allocated here. It must be freed
809 * by calling the nand_free_bbt function.
812 int nand_scan_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
814 struct nand_chip *this = mtd->priv;
817 struct nand_bbt_descr *td = this->bbt_td;
818 struct nand_bbt_descr *md = this->bbt_md;
820 len = mtd->size >> (this->bbt_erase_shift + 2);
821 /* Allocate memory (2bit per block) */
822 this->bbt = kmalloc (len, GFP_KERNEL);
824 printk (KERN_ERR "nand_scan_bbt: Out of memory\n");
827 /* Clear the memory bad block table */
828 memset (this->bbt, 0x00, len);
830 /* If no primary table decriptor is given, scan the device
831 * to build a memory based bad block table
834 if ((res = nand_memory_bbt(mtd, bd))) {
835 printk (KERN_ERR "nand_bbt: Can't scan flash and build the RAM-based BBT\n");
842 /* Allocate a temporary buffer for one eraseblock incl. oob */
843 len = (1 << this->bbt_erase_shift);
844 len += (len >> this->page_shift) * mtd->oobsize;
845 buf = kmalloc (len, GFP_KERNEL);
847 printk (KERN_ERR "nand_bbt: Out of memory\n");
853 /* Is the bbt at a given page ? */
854 if (td->options & NAND_BBT_ABSPAGE) {
855 res = read_abs_bbts (mtd, buf, td, md);
857 /* Search the bad block table using a pattern in oob */
858 res = search_read_bbts (mtd, buf, td, md);
862 res = check_create (mtd, buf, bd);
864 /* Prevent the bbt regions from erasing / writing */
865 mark_bbt_region (mtd, td);
867 mark_bbt_region (mtd, md);
875 * nand_update_bbt - [NAND Interface] update bad block table(s)
876 * @mtd: MTD device structure
877 * @offs: the offset of the newly marked block
879 * The function updates the bad block table(s)
881 int nand_update_bbt (struct mtd_info *mtd, loff_t offs)
883 struct nand_chip *this = mtd->priv;
884 int len, res = 0, writeops = 0;
887 struct nand_bbt_descr *td = this->bbt_td;
888 struct nand_bbt_descr *md = this->bbt_md;
890 if (!this->bbt || !td)
893 len = mtd->size >> (this->bbt_erase_shift + 2);
894 /* Allocate a temporary buffer for one eraseblock incl. oob */
895 len = (1 << this->bbt_erase_shift);
896 len += (len >> this->page_shift) * mtd->oobsize;
897 buf = kmalloc (len, GFP_KERNEL);
899 printk (KERN_ERR "nand_update_bbt: Out of memory\n");
903 writeops = md != NULL ? 0x03 : 0x01;
905 /* Do we have a bbt per chip ? */
906 if (td->options & NAND_BBT_PERCHIP) {
907 chip = (int) (offs >> this->chip_shift);
918 /* Write the bad block table to the device ? */
919 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
920 res = write_bbt (mtd, buf, td, md, chipsel);
924 /* Write the mirror bad block table to the device ? */
925 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
926 res = write_bbt (mtd, buf, md, td, chipsel);
934 /* Define some generic bad / good block scan pattern which are used
935 * while scanning a device for factory marked good / bad blocks. */
936 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
938 static struct nand_bbt_descr smallpage_memorybased = {
939 .options = NAND_BBT_SCAN2NDPAGE,
942 .pattern = scan_ff_pattern
945 static struct nand_bbt_descr largepage_memorybased = {
949 .pattern = scan_ff_pattern
952 static struct nand_bbt_descr smallpage_flashbased = {
953 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
956 .pattern = scan_ff_pattern
959 static struct nand_bbt_descr largepage_flashbased = {
960 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
963 .pattern = scan_ff_pattern
966 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
968 static struct nand_bbt_descr agand_flashbased = {
969 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
972 .pattern = scan_agand_pattern
975 /* Generic flash bbt decriptors
977 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
978 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
980 static struct nand_bbt_descr bbt_main_descr = {
981 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
982 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
987 .pattern = bbt_pattern
990 static struct nand_bbt_descr bbt_mirror_descr = {
991 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
992 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
997 .pattern = mirror_pattern
1001 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1002 * @mtd: MTD device structure
1004 * This function selects the default bad block table
1005 * support for the device and calls the nand_scan_bbt function
1008 int nand_default_bbt (struct mtd_info *mtd)
1010 struct nand_chip *this = mtd->priv;
1012 /* Default for AG-AND. We must use a flash based
1013 * bad block table as the devices have factory marked
1014 * _good_ blocks. Erasing those blocks leads to loss
1015 * of the good / bad information, so we _must_ store
1016 * this information in a good / bad table during
1019 if (this->options & NAND_IS_AND) {
1020 /* Use the default pattern descriptors */
1021 if (!this->bbt_td) {
1022 this->bbt_td = &bbt_main_descr;
1023 this->bbt_md = &bbt_mirror_descr;
1025 this->options |= NAND_USE_FLASH_BBT;
1026 return nand_scan_bbt (mtd, &agand_flashbased);
1030 /* Is a flash based bad block table requested ? */
1031 if (this->options & NAND_USE_FLASH_BBT) {
1032 /* Use the default pattern descriptors */
1033 if (!this->bbt_td) {
1034 this->bbt_td = &bbt_main_descr;
1035 this->bbt_md = &bbt_mirror_descr;
1037 if (!this->badblock_pattern) {
1038 this->badblock_pattern = (mtd->oobblock > 512) ?
1039 &largepage_flashbased : &smallpage_flashbased;
1042 this->bbt_td = NULL;
1043 this->bbt_md = NULL;
1044 if (!this->badblock_pattern) {
1045 this->badblock_pattern = (mtd->oobblock > 512) ?
1046 &largepage_memorybased : &smallpage_memorybased;
1049 return nand_scan_bbt (mtd, this->badblock_pattern);
1053 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1054 * @mtd: MTD device structure
1055 * @offs: offset in the device
1056 * @allowbbt: allow access to bad block table region
1059 int nand_isbad_bbt (struct mtd_info *mtd, loff_t offs, int allowbbt)
1061 struct nand_chip *this = mtd->priv;
1065 /* Get block number * 2 */
1066 block = (int) (offs >> (this->bbt_erase_shift - 1));
1067 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1069 DEBUG (MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1070 (unsigned int)offs, block >> 1, res);
1073 case 0x00: return 0;
1074 case 0x01: return 1;
1075 case 0x02: return allowbbt ? 0 : 1;
1080 EXPORT_SYMBOL (nand_scan_bbt);
1081 EXPORT_SYMBOL (nand_default_bbt);