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 1.28 2004/11/13 10:19:09 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24 * If one of the bbt's is out of date or does not exist it is (re)created.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 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 end = paglen + td->offs;
84 if (td->options & NAND_BBT_SCANEMPTY) {
85 for (i = 0; i < end; i++) {
92 /* Compare the pattern */
93 for (i = 0; i < td->len; i++) {
94 if (p[i] != td->pattern[i])
100 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 void 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)
273 scanlen = mtd->oobblock + mtd->oobsize;
274 readlen = len * mtd->oobblock;
275 ooblen = len * mtd->oobsize;
278 /* Note that numblocks is 2 * (real numblocks) here, see i+=2 below as it
279 * makes shifting and masking less painful */
280 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
284 if (chip >= this->numchips) {
285 printk (KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
286 chip + 1, this->numchips);
289 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
290 startblock = chip * numblocks;
291 numblocks += startblock;
292 from = startblock << (this->bbt_erase_shift - 1);
295 for (i = startblock; i < numblocks;) {
296 nand_read_raw (mtd, buf, from, readlen, ooblen);
297 for (j = 0; j < len; j++) {
298 if (check_pattern (&buf[j * scanlen], scanlen, mtd->oobblock, bd)) {
299 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
300 printk (KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
301 i >> 1, (unsigned int) from);
306 from += (1 << this->bbt_erase_shift);
311 * search_bbt - [GENERIC] scan the device for a specific bad block table
312 * @mtd: MTD device structure
313 * @buf: temporary buffer
314 * @td: descriptor for the bad block table
316 * Read the bad block table by searching for a given ident pattern.
317 * Search is preformed either from the beginning up or from the end of
318 * the device downwards. The search starts always at the start of a
320 * If the option NAND_BBT_PERCHIP is given, each chip is searched
321 * for a bbt, which contains the bad block information of this chip.
322 * This is neccecary to provide support for certain DOC devices.
324 * The bbt ident pattern resides in the oob area of the first page
327 static int search_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
329 struct nand_chip *this = mtd->priv;
331 int bits, startblock, block, dir;
332 int scanlen = mtd->oobblock + mtd->oobsize;
335 /* Search direction top -> down ? */
336 if (td->options & NAND_BBT_LASTBLOCK) {
337 startblock = (mtd->size >> this->bbt_erase_shift) -1;
344 /* Do we have a bbt per chip ? */
345 if (td->options & NAND_BBT_PERCHIP) {
346 chips = this->numchips;
347 bbtblocks = this->chipsize >> this->bbt_erase_shift;
348 startblock &= bbtblocks - 1;
351 bbtblocks = mtd->size >> this->bbt_erase_shift;
354 /* Number of bits for each erase block in the bbt */
355 bits = td->options & NAND_BBT_NRBITS_MSK;
357 for (i = 0; i < chips; i++) {
358 /* Reset version information */
361 /* Scan the maximum number of blocks */
362 for (block = 0; block < td->maxblocks; block++) {
363 int actblock = startblock + dir * block;
364 /* Read first page */
365 nand_read_raw (mtd, buf, actblock << this->bbt_erase_shift, mtd->oobblock, mtd->oobsize);
366 if (!check_pattern(buf, scanlen, mtd->oobblock, td)) {
367 td->pages[i] = actblock << (this->bbt_erase_shift - this->page_shift);
368 if (td->options & NAND_BBT_VERSION) {
369 td->version[i] = buf[mtd->oobblock + td->veroffs];
374 startblock += this->chipsize >> this->bbt_erase_shift;
376 /* Check, if we found a bbt for each requested chip */
377 for (i = 0; i < chips; i++) {
378 if (td->pages[i] == -1)
379 printk (KERN_WARNING "Bad block table not found for chip %d\n", i);
381 printk (KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i], td->version[i]);
387 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
388 * @mtd: MTD device structure
389 * @buf: temporary buffer
390 * @td: descriptor for the bad block table
391 * @md: descriptor for the bad block table mirror
393 * Search and read the bad block table(s)
395 static int search_read_bbts (struct mtd_info *mtd, uint8_t *buf,
396 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
398 /* Search the primary table */
399 search_bbt (mtd, buf, td);
401 /* Search the mirror table */
403 search_bbt (mtd, buf, md);
405 /* Force result check */
411 * write_bbt - [GENERIC] (Re)write the bad block table
413 * @mtd: MTD device structure
414 * @buf: temporary buffer
415 * @td: descriptor for the bad block table
416 * @md: descriptor for the bad block table mirror
417 * @chipsel: selector for a specific chip, -1 for all
419 * (Re)write the bad block table
422 static int write_bbt (struct mtd_info *mtd, uint8_t *buf,
423 struct nand_bbt_descr *td, struct nand_bbt_descr *md, int chipsel)
425 struct nand_chip *this = mtd->priv;
426 struct nand_oobinfo oobinfo;
427 struct erase_info einfo;
428 int i, j, res, chip = 0;
429 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
430 int nrchips, bbtoffs, pageoffs;
432 uint8_t rcode = td->reserved_block_code;
433 size_t retlen, len = 0;
438 /* Write bad block table per chip rather than per device ? */
439 if (td->options & NAND_BBT_PERCHIP) {
440 numblocks = (int) (this->chipsize >> this->bbt_erase_shift);
441 /* Full device write or specific chip ? */
443 nrchips = this->numchips;
445 nrchips = chipsel + 1;
449 numblocks = (int) (mtd->size >> this->bbt_erase_shift);
453 /* Loop through the chips */
454 for (; chip < nrchips; chip++) {
456 /* There was already a version of the table, reuse the page
457 * This applies for absolute placement too, as we have the
458 * page nr. in td->pages.
460 if (td->pages[chip] != -1) {
461 page = td->pages[chip];
465 /* Automatic placement of the bad block table */
466 /* Search direction top -> down ? */
467 if (td->options & NAND_BBT_LASTBLOCK) {
468 startblock = numblocks * (chip + 1) - 1;
471 startblock = chip * numblocks;
475 for (i = 0; i < td->maxblocks; i++) {
476 int block = startblock + dir * i;
477 /* Check, if the block is bad */
478 switch ((this->bbt[block >> 2] >> (2 * (block & 0x03))) & 0x03) {
483 page = block << (this->bbt_erase_shift - this->page_shift);
484 /* Check, if the block is used by the mirror table */
485 if (!md || md->pages[chip] != page)
488 printk (KERN_ERR "No space left to write bad block table\n");
492 /* Set up shift count and masks for the flash table */
493 bits = td->options & NAND_BBT_NRBITS_MSK;
495 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01; msk[2] = ~rcode; msk[3] = 0x01; break;
496 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01; msk[2] = ~rcode; msk[3] = 0x03; break;
497 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C; msk[2] = ~rcode; msk[3] = 0x0f; break;
498 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F; msk[2] = ~rcode; msk[3] = 0xff; break;
499 default: return -EINVAL;
502 bbtoffs = chip * (numblocks >> 2);
504 to = ((loff_t) page) << this->page_shift;
506 memcpy (&oobinfo, this->autooob, sizeof(oobinfo));
507 oobinfo.useecc = MTD_NANDECC_PLACEONLY;
509 /* Must we save the block contents ? */
510 if (td->options & NAND_BBT_SAVECONTENT) {
511 /* Make it block aligned */
512 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
513 len = 1 << this->bbt_erase_shift;
514 res = mtd->read_ecc (mtd, to, len, &retlen, buf, &buf[len], &oobinfo);
517 printk (KERN_INFO "nand_bbt: Error reading block for writing the bad block table\n");
520 printk (KERN_WARNING "nand_bbt: ECC error while reading block for writing bad block table\n");
522 /* Calc the byte offset in the buffer */
523 pageoffs = page - (int)(to >> this->page_shift);
524 offs = pageoffs << this->page_shift;
525 /* Preset the bbt area with 0xff */
526 memset (&buf[offs], 0xff, (size_t)(numblocks >> sft));
527 /* Preset the bbt's oob area with 0xff */
528 memset (&buf[len + pageoffs * mtd->oobsize], 0xff,
529 ((len >> this->page_shift) - pageoffs) * mtd->oobsize);
530 if (td->options & NAND_BBT_VERSION) {
531 buf[len + (pageoffs * mtd->oobsize) + td->veroffs] = td->version[chip];
535 len = (size_t) (numblocks >> sft);
536 /* Make it page aligned ! */
537 len = (len + (mtd->oobblock-1)) & ~(mtd->oobblock-1);
538 /* Preset the buffer with 0xff */
539 memset (buf, 0xff, len + (len >> this->page_shift) * mtd->oobsize);
541 /* Pattern is located in oob area of first page */
542 memcpy (&buf[len + td->offs], td->pattern, td->len);
543 if (td->options & NAND_BBT_VERSION) {
544 buf[len + td->veroffs] = td->version[chip];
548 /* walk through the memory table */
549 for (i = 0; i < numblocks; ) {
551 dat = this->bbt[bbtoffs + (i >> 2)];
552 for (j = 0; j < 4; j++ , i++) {
553 int sftcnt = (i << (3 - sft)) & sftmsk;
554 /* Do not store the reserved bbt blocks ! */
555 buf[offs + (i >> sft)] &= ~(msk[dat & 0x03] << sftcnt);
560 memset (&einfo, 0, sizeof (einfo));
562 einfo.addr = (unsigned long) to;
563 einfo.len = 1 << this->bbt_erase_shift;
564 res = nand_erase_nand (mtd, &einfo, 1);
566 printk (KERN_WARNING "nand_bbt: Error during block erase: %d\n", res);
570 res = mtd->write_ecc (mtd, to, len, &retlen, buf, &buf[len], &oobinfo);
572 printk (KERN_WARNING "nand_bbt: Error while writing bad block table %d\n", res);
575 printk (KERN_DEBUG "Bad block table written to 0x%08x, version 0x%02X\n",
576 (unsigned int) to, td->version[chip]);
578 /* Mark it as used */
579 td->pages[chip] = page;
585 * nand_memory_bbt - [GENERIC] create a memory based bad block table
586 * @mtd: MTD device structure
587 * @bd: descriptor for the good/bad block search pattern
589 * The function creates a memory based bbt by scanning the device
590 * for manufacturer / software marked good / bad blocks
592 static int nand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
594 struct nand_chip *this = mtd->priv;
596 /* Ensure that we only scan for the pattern and nothing else */
598 create_bbt (mtd, this->data_buf, bd, -1);
603 * check_create - [GENERIC] create and write bbt(s) if neccecary
604 * @mtd: MTD device structure
605 * @buf: temporary buffer
606 * @bd: descriptor for the good/bad block search pattern
608 * The function checks the results of the previous call to read_bbt
609 * and creates / updates the bbt(s) if neccecary
610 * Creation is neccecary if no bbt was found for the chip/device
611 * Update is neccecary if one of the tables is missing or the
612 * version nr. of one table is less than the other
614 static int check_create (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
616 int i, chips, writeops, chipsel, res;
617 struct nand_chip *this = mtd->priv;
618 struct nand_bbt_descr *td = this->bbt_td;
619 struct nand_bbt_descr *md = this->bbt_md;
620 struct nand_bbt_descr *rd, *rd2;
622 /* Do we have a bbt per chip ? */
623 if (td->options & NAND_BBT_PERCHIP)
624 chips = this->numchips;
628 for (i = 0; i < chips; i++) {
632 /* Per chip or per device ? */
633 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
634 /* Mirrored table avilable ? */
636 if (td->pages[i] == -1 && md->pages[i] == -1) {
641 if (td->pages[i] == -1) {
643 td->version[i] = md->version[i];
648 if (md->pages[i] == -1) {
650 md->version[i] = td->version[i];
655 if (td->version[i] == md->version[i]) {
657 if (!(td->options & NAND_BBT_VERSION))
662 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
664 md->version[i] = td->version[i];
668 td->version[i] = md->version[i];
675 if (td->pages[i] == -1) {
683 /* Create the bad block table by scanning the device ? */
684 if (!(td->options & NAND_BBT_CREATE))
687 /* Create the table in memory by scanning the chip(s) */
688 create_bbt (mtd, buf, bd, chipsel);
694 /* read back first ? */
696 read_abs_bbt (mtd, buf, rd, chipsel);
697 /* If they weren't versioned, read both. */
699 read_abs_bbt (mtd, buf, rd2, chipsel);
701 /* Write the bad block table to the device ? */
702 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
703 res = write_bbt (mtd, buf, td, md, chipsel);
708 /* Write the mirror bad block table to the device ? */
709 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
710 res = write_bbt (mtd, buf, md, td, chipsel);
719 * mark_bbt_regions - [GENERIC] mark the bad block table regions
720 * @mtd: MTD device structure
721 * @td: bad block table descriptor
723 * The bad block table regions are marked as "bad" to prevent
724 * accidental erasures / writes. The regions are identified by
727 static void mark_bbt_region (struct mtd_info *mtd, struct nand_bbt_descr *td)
729 struct nand_chip *this = mtd->priv;
730 int i, j, chips, block, nrblocks, update;
731 uint8_t oldval, newval;
733 /* Do we have a bbt per chip ? */
734 if (td->options & NAND_BBT_PERCHIP) {
735 chips = this->numchips;
736 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
739 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
742 for (i = 0; i < chips; i++) {
743 if ((td->options & NAND_BBT_ABSPAGE) ||
744 !(td->options & NAND_BBT_WRITE)) {
745 if (td->pages[i] == -1) continue;
746 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
748 oldval = this->bbt[(block >> 3)];
749 newval = oldval | (0x2 << (block & 0x06));
750 this->bbt[(block >> 3)] = newval;
751 if ((oldval != newval) && td->reserved_block_code)
752 nand_update_bbt(mtd, block << (this->bbt_erase_shift - 1));
756 if (td->options & NAND_BBT_LASTBLOCK)
757 block = ((i + 1) * nrblocks) - td->maxblocks;
759 block = i * nrblocks;
761 for (j = 0; j < td->maxblocks; j++) {
762 oldval = this->bbt[(block >> 3)];
763 newval = oldval | (0x2 << (block & 0x06));
764 this->bbt[(block >> 3)] = newval;
765 if (oldval != newval) update = 1;
768 /* If we want reserved blocks to be recorded to flash, and some
769 new ones have been marked, then we need to update the stored
770 bbts. This should only happen once. */
771 if (update && td->reserved_block_code)
772 nand_update_bbt(mtd, (block - 2) << (this->bbt_erase_shift - 1));
777 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
778 * @mtd: MTD device structure
779 * @bd: descriptor for the good/bad block search pattern
781 * The function checks, if a bad block table(s) is/are already
782 * available. If not it scans the device for manufacturer
783 * marked good / bad blocks and writes the bad block table(s) to
784 * the selected place.
786 * The bad block table memory is allocated here. It must be freed
787 * by calling the nand_free_bbt function.
790 int nand_scan_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
792 struct nand_chip *this = mtd->priv;
795 struct nand_bbt_descr *td = this->bbt_td;
796 struct nand_bbt_descr *md = this->bbt_md;
798 len = mtd->size >> (this->bbt_erase_shift + 2);
799 /* Allocate memory (2bit per block) */
800 this->bbt = kmalloc (len, GFP_KERNEL);
802 printk (KERN_ERR "nand_scan_bbt: Out of memory\n");
805 /* Clear the memory bad block table */
806 memset (this->bbt, 0x00, len);
808 /* If no primary table decriptor is given, scan the device
809 * to build a memory based bad block table
812 return nand_memory_bbt(mtd, bd);
814 /* Allocate a temporary buffer for one eraseblock incl. oob */
815 len = (1 << this->bbt_erase_shift);
816 len += (len >> this->page_shift) * mtd->oobsize;
817 buf = kmalloc (len, GFP_KERNEL);
819 printk (KERN_ERR "nand_bbt: Out of memory\n");
825 /* Is the bbt at a given page ? */
826 if (td->options & NAND_BBT_ABSPAGE) {
827 res = read_abs_bbts (mtd, buf, td, md);
829 /* Search the bad block table using a pattern in oob */
830 res = search_read_bbts (mtd, buf, td, md);
834 res = check_create (mtd, buf, bd);
836 /* Prevent the bbt regions from erasing / writing */
837 mark_bbt_region (mtd, td);
839 mark_bbt_region (mtd, md);
847 * nand_update_bbt - [NAND Interface] update bad block table(s)
848 * @mtd: MTD device structure
849 * @offs: the offset of the newly marked block
851 * The function updates the bad block table(s)
853 int nand_update_bbt (struct mtd_info *mtd, loff_t offs)
855 struct nand_chip *this = mtd->priv;
856 int len, res = 0, writeops = 0;
859 struct nand_bbt_descr *td = this->bbt_td;
860 struct nand_bbt_descr *md = this->bbt_md;
862 if (!this->bbt || !td)
865 len = mtd->size >> (this->bbt_erase_shift + 2);
866 /* Allocate a temporary buffer for one eraseblock incl. oob */
867 len = (1 << this->bbt_erase_shift);
868 len += (len >> this->page_shift) * mtd->oobsize;
869 buf = kmalloc (len, GFP_KERNEL);
871 printk (KERN_ERR "nand_update_bbt: Out of memory\n");
875 writeops = md != NULL ? 0x03 : 0x01;
877 /* Do we have a bbt per chip ? */
878 if (td->options & NAND_BBT_PERCHIP) {
879 chip = (int) (offs >> this->chip_shift);
890 /* Write the bad block table to the device ? */
891 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
892 res = write_bbt (mtd, buf, td, md, chipsel);
896 /* Write the mirror bad block table to the device ? */
897 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
898 res = write_bbt (mtd, buf, md, td, chipsel);
906 /* Define some generic bad / good block scan pattern which are used
907 * while scanning a device for factory marked good / bad blocks
909 * The memory based patterns just
911 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
913 static struct nand_bbt_descr smallpage_memorybased = {
917 .pattern = scan_ff_pattern
920 static struct nand_bbt_descr largepage_memorybased = {
924 .pattern = scan_ff_pattern
927 static struct nand_bbt_descr smallpage_flashbased = {
928 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
931 .pattern = scan_ff_pattern
934 static struct nand_bbt_descr largepage_flashbased = {
935 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
938 .pattern = scan_ff_pattern
941 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
943 static struct nand_bbt_descr agand_flashbased = {
944 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
947 .pattern = scan_agand_pattern
950 /* Generic flash bbt decriptors
952 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
953 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
955 static struct nand_bbt_descr bbt_main_descr = {
956 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
957 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
962 .pattern = bbt_pattern
965 static struct nand_bbt_descr bbt_mirror_descr = {
966 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
967 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
972 .pattern = mirror_pattern
976 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
977 * @mtd: MTD device structure
979 * This function selects the default bad block table
980 * support for the device and calls the nand_scan_bbt function
983 int nand_default_bbt (struct mtd_info *mtd)
985 struct nand_chip *this = mtd->priv;
987 /* Default for AG-AND. We must use a flash based
988 * bad block table as the devices have factory marked
989 * _good_ blocks. Erasing those blocks leads to loss
990 * of the good / bad information, so we _must_ store
991 * this information in a good / bad table during
994 if (this->options & NAND_IS_AND) {
995 /* Use the default pattern descriptors */
997 this->bbt_td = &bbt_main_descr;
998 this->bbt_md = &bbt_mirror_descr;
1000 this->options |= NAND_USE_FLASH_BBT;
1001 return nand_scan_bbt (mtd, &agand_flashbased);
1005 /* Is a flash based bad block table requested ? */
1006 if (this->options & NAND_USE_FLASH_BBT) {
1007 /* Use the default pattern descriptors */
1008 if (!this->bbt_td) {
1009 this->bbt_td = &bbt_main_descr;
1010 this->bbt_md = &bbt_mirror_descr;
1012 if (!this->badblock_pattern) {
1013 this->badblock_pattern = (mtd->oobblock > 512) ?
1014 &largepage_flashbased : &smallpage_flashbased;
1017 this->bbt_td = NULL;
1018 this->bbt_md = NULL;
1019 if (!this->badblock_pattern) {
1020 this->badblock_pattern = (mtd->oobblock > 512) ?
1021 &largepage_memorybased : &smallpage_memorybased;
1024 return nand_scan_bbt (mtd, this->badblock_pattern);
1028 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1029 * @mtd: MTD device structure
1030 * @offs: offset in the device
1031 * @allowbbt: allow access to bad block table region
1034 int nand_isbad_bbt (struct mtd_info *mtd, loff_t offs, int allowbbt)
1036 struct nand_chip *this = mtd->priv;
1040 /* Get block number * 2 */
1041 block = (int) (offs >> (this->bbt_erase_shift - 1));
1042 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1044 DEBUG (MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1045 (unsigned int)offs, res, block >> 1);
1048 case 0x00: return 0;
1049 case 0x01: return 1;
1050 case 0x02: return allowbbt ? 0 : 1;
1055 EXPORT_SYMBOL (nand_scan_bbt);
1056 EXPORT_SYMBOL (nand_default_bbt);