2 * drivers/mtd/nand_bbt.c
5 * Bad block table support for the NAND driver
7 * Copyright © 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 no flash based BBT
17 * (NAND_BBT_USE_FLASH) is specified then the device is scanned for factory
18 * marked good / bad blocks. This information is used to create a memory BBT.
19 * Once a new bad block is discovered then the "factory" information is updated
21 * If a flash based BBT is specified then the function first tries to find the
22 * BBT on flash. If a BBT is found then the contents are read and the memory
23 * based BBT is created. If a mirrored BBT is selected then the mirror is
24 * searched too and the versions are compared. If the mirror has a greater
25 * version number, then the mirror BBT is used to build the memory based BBT.
26 * If the tables are not versioned, then we "or" the bad block information.
27 * If one of the BBTs is out of date or does not exist it is (re)created.
28 * If no BBT exists at all then the device is scanned for factory marked
29 * good / bad blocks and the bad block tables are created.
31 * For manufacturer created BBTs like the one found on M-SYS DOC devices
32 * the BBT is searched and read but never created
34 * The auto generated bad block table is located in the last good blocks
35 * of the device. The table is mirrored, so it can be updated eventually.
36 * The table is marked in the OOB area with an ident pattern and a version
37 * number which indicates which of both tables is more up to date. If the NAND
38 * controller needs the complete OOB area for the ECC information then the
39 * option NAND_BBT_NO_OOB should be used (along with NAND_BBT_USE_FLASH, of
40 * course): it moves the ident pattern and the version byte into the data area
41 * and the OOB area will remain untouched.
43 * The table uses 2 bits per block
45 * 00b: block is factory marked bad
46 * 01b, 10b: block is marked bad due to wear
48 * The memory bad block table uses the following scheme:
50 * 01b: block is marked bad due to wear
51 * 10b: block is reserved (to protect the bbt area)
52 * 11b: block is factory marked bad
54 * Multichip devices like DOC store the bad block info per floor.
56 * Following assumptions are made:
57 * - bbts start at a page boundary, if autolocated on a block boundary
58 * - the space necessary for a bbt in FLASH does not exceed a block boundary
63 #include <linux/slab.h>
64 #include <linux/types.h>
65 #include <linux/mtd/mtd.h>
66 #include <linux/mtd/bbm.h>
67 #include <linux/mtd/nand.h>
68 #include <linux/mtd/nand_ecc.h>
69 #include <linux/bitops.h>
70 #include <linux/delay.h>
71 #include <linux/vmalloc.h>
72 #include <linux/export.h>
73 #include <linux/string.h>
77 #include <linux/compat.h>
79 #include <linux/mtd/mtd.h>
80 #include <linux/mtd/bbm.h>
81 #include <linux/mtd/nand.h>
82 #include <linux/mtd/nand_ecc.h>
83 #include <linux/bitops.h>
84 #include <linux/string.h>
87 #define BBT_BLOCK_GOOD 0x00
88 #define BBT_BLOCK_WORN 0x01
89 #define BBT_BLOCK_RESERVED 0x02
90 #define BBT_BLOCK_FACTORY_BAD 0x03
92 #define BBT_ENTRY_MASK 0x03
93 #define BBT_ENTRY_SHIFT 2
95 static int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
97 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
99 uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
100 entry >>= (block & BBT_ENTRY_MASK) * 2;
101 return entry & BBT_ENTRY_MASK;
104 static inline void bbt_mark_entry(struct nand_chip *chip, int block,
107 uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);
108 chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;
111 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
113 if (memcmp(buf, td->pattern, td->len))
119 * check_pattern - [GENERIC] check if a pattern is in the buffer
120 * @buf: the buffer to search
121 * @len: the length of buffer to search
122 * @paglen: the pagelength
123 * @td: search pattern descriptor
125 * Check for a pattern at the given place. Used to search bad block tables and
126 * good / bad block identifiers.
128 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
130 if (td->options & NAND_BBT_NO_OOB)
131 return check_pattern_no_oob(buf, td);
133 /* Compare the pattern */
134 if (memcmp(buf + paglen + td->offs, td->pattern, td->len))
141 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
142 * @buf: the buffer to search
143 * @td: search pattern descriptor
145 * Check for a pattern at the given place. Used to search bad block tables and
146 * good / bad block identifiers. Same as check_pattern, but no optional empty
149 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
151 /* Compare the pattern */
152 if (memcmp(buf + td->offs, td->pattern, td->len))
158 * add_marker_len - compute the length of the marker in data area
159 * @td: BBT descriptor used for computation
161 * The length will be 0 if the marker is located in OOB area.
163 static u32 add_marker_len(struct nand_bbt_descr *td)
167 if (!(td->options & NAND_BBT_NO_OOB))
171 if (td->options & NAND_BBT_VERSION)
177 * read_bbt - [GENERIC] Read the bad block table starting from page
178 * @mtd: MTD device structure
179 * @buf: temporary buffer
180 * @page: the starting page
181 * @num: the number of bbt descriptors to read
182 * @td: the bbt describtion table
183 * @offs: block number offset in the table
185 * Read the bad block table starting from page.
187 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
188 struct nand_bbt_descr *td, int offs)
190 int res, ret = 0, i, j, act = 0;
191 struct nand_chip *this = mtd->priv;
192 size_t retlen, len, totlen;
194 int bits = td->options & NAND_BBT_NRBITS_MSK;
195 uint8_t msk = (uint8_t)((1 << bits) - 1);
197 int reserved_block_code = td->reserved_block_code;
199 totlen = (num * bits) >> 3;
200 marker_len = add_marker_len(td);
201 from = ((loff_t)page) << this->page_shift;
204 len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
207 * In case the BBT marker is not in the OOB area it
208 * will be just in the first page.
214 res = mtd_read(mtd, from, len, &retlen, buf);
216 if (mtd_is_eccerr(res)) {
217 pr_info("nand_bbt: ECC error in BBT at "
218 "0x%012llx\n", from & ~mtd->writesize);
220 } else if (mtd_is_bitflip(res)) {
221 pr_info("nand_bbt: corrected error in BBT at "
222 "0x%012llx\n", from & ~mtd->writesize);
225 pr_info("nand_bbt: error reading BBT\n");
231 for (i = 0; i < len; i++) {
232 uint8_t dat = buf[i];
233 for (j = 0; j < 8; j += bits, act++) {
234 uint8_t tmp = (dat >> j) & msk;
237 if (reserved_block_code && (tmp == reserved_block_code)) {
238 pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
239 (loff_t)(offs + act) <<
240 this->bbt_erase_shift);
241 bbt_mark_entry(this, offs + act,
243 mtd->ecc_stats.bbtblocks++;
247 * Leave it for now, if it's matured we can
248 * move this message to pr_debug.
250 pr_info("nand_read_bbt: bad block at 0x%012llx\n",
251 (loff_t)(offs + act) <<
252 this->bbt_erase_shift);
253 /* Factory marked bad or worn out? */
255 bbt_mark_entry(this, offs + act,
256 BBT_BLOCK_FACTORY_BAD);
258 bbt_mark_entry(this, offs + act,
260 mtd->ecc_stats.badblocks++;
270 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
271 * @mtd: MTD device structure
272 * @buf: temporary buffer
273 * @td: descriptor for the bad block table
274 * @chip: read the table for a specific chip, -1 read all chips; applies only if
275 * NAND_BBT_PERCHIP option is set
277 * Read the bad block table for all chips starting at a given page. We assume
278 * that the bbt bits are in consecutive order.
280 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
282 struct nand_chip *this = mtd->priv;
285 if (td->options & NAND_BBT_PERCHIP) {
287 for (i = 0; i < this->numchips; i++) {
288 if (chip == -1 || chip == i)
289 res = read_bbt(mtd, buf, td->pages[i],
290 this->chipsize >> this->bbt_erase_shift,
294 offs += this->chipsize >> this->bbt_erase_shift;
297 res = read_bbt(mtd, buf, td->pages[0],
298 mtd->size >> this->bbt_erase_shift, td, 0);
305 /* BBT marker is in the first page, no OOB */
306 static int scan_read_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
307 struct nand_bbt_descr *td)
313 if (td->options & NAND_BBT_VERSION)
316 return mtd_read(mtd, offs, len, &retlen, buf);
320 * scan_read_oob - [GENERIC] Scan data+OOB region to buffer
321 * @mtd: MTD device structure
322 * @buf: temporary buffer
323 * @offs: offset at which to scan
324 * @len: length of data region to read
326 * Scan read data from data+OOB. May traverse multiple pages, interleaving
327 * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest"
328 * ECC condition (error or bitflip). May quit on the first (non-ECC) error.
330 static int scan_read_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
333 struct mtd_oob_ops ops;
336 ops.mode = MTD_OPS_PLACE_OOB;
338 ops.ooblen = mtd->oobsize;
342 ops.len = min(len, (size_t)mtd->writesize);
343 ops.oobbuf = buf + ops.len;
345 res = mtd_read_oob(mtd, offs, &ops);
347 if (!mtd_is_bitflip_or_eccerr(res))
349 else if (mtd_is_eccerr(res) || !ret)
353 buf += mtd->oobsize + mtd->writesize;
354 len -= mtd->writesize;
355 offs += mtd->writesize;
360 static int scan_read(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
361 size_t len, struct nand_bbt_descr *td)
363 if (td->options & NAND_BBT_NO_OOB)
364 return scan_read_data(mtd, buf, offs, td);
366 return scan_read_oob(mtd, buf, offs, len);
369 /* Scan write data with oob to flash */
370 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
371 uint8_t *buf, uint8_t *oob)
373 struct mtd_oob_ops ops;
375 ops.mode = MTD_OPS_PLACE_OOB;
377 ops.ooblen = mtd->oobsize;
382 return mtd_write_oob(mtd, offs, &ops);
385 static u32 bbt_get_ver_offs(struct mtd_info *mtd, struct nand_bbt_descr *td)
387 u32 ver_offs = td->veroffs;
389 if (!(td->options & NAND_BBT_NO_OOB))
390 ver_offs += mtd->writesize;
395 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
396 * @mtd: MTD device structure
397 * @buf: temporary buffer
398 * @td: descriptor for the bad block table
399 * @md: descriptor for the bad block table mirror
401 * Read the bad block table(s) for all chips starting at a given page. We
402 * assume that the bbt bits are in consecutive order.
404 static void read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
405 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
407 struct nand_chip *this = mtd->priv;
409 /* Read the primary version, if available */
410 if (td->options & NAND_BBT_VERSION) {
411 scan_read(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
413 td->version[0] = buf[bbt_get_ver_offs(mtd, td)];
414 pr_info("Bad block table at page %d, version 0x%02X\n",
415 td->pages[0], td->version[0]);
418 /* Read the mirror version, if available */
419 if (md && (md->options & NAND_BBT_VERSION)) {
420 scan_read(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
422 md->version[0] = buf[bbt_get_ver_offs(mtd, md)];
423 pr_info("Bad block table at page %d, version 0x%02X\n",
424 md->pages[0], md->version[0]);
428 /* Scan a given block partially */
429 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
430 loff_t offs, uint8_t *buf, int numpages)
432 struct mtd_oob_ops ops;
435 ops.ooblen = mtd->oobsize;
439 ops.mode = MTD_OPS_PLACE_OOB;
441 for (j = 0; j < numpages; j++) {
443 * Read the full oob until read_oob is fixed to handle single
444 * byte reads for 16 bit buswidth.
446 ret = mtd_read_oob(mtd, offs, &ops);
447 /* Ignore ECC errors when checking for BBM */
448 if (ret && !mtd_is_bitflip_or_eccerr(ret))
451 if (check_short_pattern(buf, bd))
454 offs += mtd->writesize;
460 * create_bbt - [GENERIC] Create a bad block table by scanning the device
461 * @mtd: MTD device structure
462 * @buf: temporary buffer
463 * @bd: descriptor for the good/bad block search pattern
464 * @chip: create the table for a specific chip, -1 read all chips; applies only
465 * if NAND_BBT_PERCHIP option is set
467 * Create a bad block table by scanning the device for the given good/bad block
470 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
471 struct nand_bbt_descr *bd, int chip)
473 struct nand_chip *this = mtd->priv;
474 int i, numblocks, numpages;
478 pr_info("Scanning device for bad blocks\n");
480 if (bd->options & NAND_BBT_SCAN2NDPAGE)
486 numblocks = mtd->size >> this->bbt_erase_shift;
490 if (chip >= this->numchips) {
491 pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
492 chip + 1, this->numchips);
495 numblocks = this->chipsize >> this->bbt_erase_shift;
496 startblock = chip * numblocks;
497 numblocks += startblock;
498 from = (loff_t)startblock << this->bbt_erase_shift;
501 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
502 from += mtd->erasesize - (mtd->writesize * numpages);
504 for (i = startblock; i < numblocks; i++) {
507 BUG_ON(bd->options & NAND_BBT_NO_OOB);
509 ret = scan_block_fast(mtd, bd, from, buf, numpages);
514 bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
515 pr_warn("Bad eraseblock %d at 0x%012llx\n",
516 i, (unsigned long long)from);
517 mtd->ecc_stats.badblocks++;
520 from += (1 << this->bbt_erase_shift);
526 * search_bbt - [GENERIC] scan the device for a specific bad block table
527 * @mtd: MTD device structure
528 * @buf: temporary buffer
529 * @td: descriptor for the bad block table
531 * Read the bad block table by searching for a given ident pattern. Search is
532 * preformed either from the beginning up or from the end of the device
533 * downwards. The search starts always at the start of a block. If the option
534 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
535 * the bad block information of this chip. This is necessary to provide support
536 * for certain DOC devices.
538 * The bbt ident pattern resides in the oob area of the first page in a block.
540 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
542 struct nand_chip *this = mtd->priv;
545 int bits, startblock, block, dir;
547 int startblock, block, dir;
549 int scanlen = mtd->writesize + mtd->oobsize;
551 int blocktopage = this->bbt_erase_shift - this->page_shift;
553 /* Search direction top -> down? */
554 if (td->options & NAND_BBT_LASTBLOCK) {
555 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
562 /* Do we have a bbt per chip? */
563 if (td->options & NAND_BBT_PERCHIP) {
564 chips = this->numchips;
565 bbtblocks = this->chipsize >> this->bbt_erase_shift;
566 startblock &= bbtblocks - 1;
569 bbtblocks = mtd->size >> this->bbt_erase_shift;
573 /* Number of bits for each erase block in the bbt */
574 bits = td->options & NAND_BBT_NRBITS_MSK;
577 for (i = 0; i < chips; i++) {
578 /* Reset version information */
581 /* Scan the maximum number of blocks */
582 for (block = 0; block < td->maxblocks; block++) {
584 int actblock = startblock + dir * block;
585 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
587 /* Read first page */
588 scan_read(mtd, buf, offs, mtd->writesize, td);
589 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
590 td->pages[i] = actblock << blocktopage;
591 if (td->options & NAND_BBT_VERSION) {
592 offs = bbt_get_ver_offs(mtd, td);
593 td->version[i] = buf[offs];
598 startblock += this->chipsize >> this->bbt_erase_shift;
600 /* Check, if we found a bbt for each requested chip */
601 for (i = 0; i < chips; i++) {
602 if (td->pages[i] == -1)
603 pr_warn("Bad block table not found for chip %d\n", i);
605 pr_info("Bad block table found at page %d, version "
606 "0x%02X\n", td->pages[i], td->version[i]);
612 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
613 * @mtd: MTD device structure
614 * @buf: temporary buffer
615 * @td: descriptor for the bad block table
616 * @md: descriptor for the bad block table mirror
618 * Search and read the bad block table(s).
620 static void search_read_bbts(struct mtd_info *mtd, uint8_t *buf,
621 struct nand_bbt_descr *td,
622 struct nand_bbt_descr *md)
624 /* Search the primary table */
625 search_bbt(mtd, buf, td);
627 /* Search the mirror table */
629 search_bbt(mtd, buf, md);
633 * write_bbt - [GENERIC] (Re)write the bad block table
634 * @mtd: MTD device structure
635 * @buf: temporary buffer
636 * @td: descriptor for the bad block table
637 * @md: descriptor for the bad block table mirror
638 * @chipsel: selector for a specific chip, -1 for all
640 * (Re)write the bad block table.
642 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
643 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
646 struct nand_chip *this = mtd->priv;
647 struct erase_info einfo;
648 int i, res, chip = 0;
649 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
650 int nrchips, pageoffs, ooboffs;
652 uint8_t rcode = td->reserved_block_code;
653 size_t retlen, len = 0;
655 struct mtd_oob_ops ops;
657 ops.ooblen = mtd->oobsize;
660 ops.mode = MTD_OPS_PLACE_OOB;
664 /* Write bad block table per chip rather than per device? */
665 if (td->options & NAND_BBT_PERCHIP) {
666 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
667 /* Full device write or specific chip? */
669 nrchips = this->numchips;
671 nrchips = chipsel + 1;
675 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
679 /* Loop through the chips */
680 for (; chip < nrchips; chip++) {
682 * There was already a version of the table, reuse the page
683 * This applies for absolute placement too, as we have the
684 * page nr. in td->pages.
686 if (td->pages[chip] != -1) {
687 page = td->pages[chip];
692 * Automatic placement of the bad block table. Search direction
695 if (td->options & NAND_BBT_LASTBLOCK) {
696 startblock = numblocks * (chip + 1) - 1;
699 startblock = chip * numblocks;
703 for (i = 0; i < td->maxblocks; i++) {
704 int block = startblock + dir * i;
705 /* Check, if the block is bad */
706 switch (bbt_get_entry(this, block)) {
708 case BBT_BLOCK_FACTORY_BAD:
712 (this->bbt_erase_shift - this->page_shift);
713 /* Check, if the block is used by the mirror table */
714 if (!md || md->pages[chip] != page)
717 pr_err("No space left to write bad block table\n");
721 /* Set up shift count and masks for the flash table */
722 bits = td->options & NAND_BBT_NRBITS_MSK;
725 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
728 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
731 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
734 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
737 default: return -EINVAL;
740 to = ((loff_t)page) << this->page_shift;
742 /* Must we save the block contents? */
743 if (td->options & NAND_BBT_SAVECONTENT) {
744 /* Make it block aligned */
745 to &= ~((loff_t)((1 << this->bbt_erase_shift) - 1));
746 len = 1 << this->bbt_erase_shift;
747 res = mtd_read(mtd, to, len, &retlen, buf);
750 pr_info("nand_bbt: error reading block "
751 "for writing the bad block table\n");
754 pr_warn("nand_bbt: ECC error while reading "
755 "block for writing bad block table\n");
758 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
759 ops.oobbuf = &buf[len];
760 res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
761 if (res < 0 || ops.oobretlen != ops.ooblen)
764 /* Calc the byte offset in the buffer */
765 pageoffs = page - (int)(to >> this->page_shift);
766 offs = pageoffs << this->page_shift;
767 /* Preset the bbt area with 0xff */
768 memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
769 ooboffs = len + (pageoffs * mtd->oobsize);
771 } else if (td->options & NAND_BBT_NO_OOB) {
774 /* The version byte */
775 if (td->options & NAND_BBT_VERSION)
778 len = (size_t)(numblocks >> sft);
780 /* Make it page aligned! */
781 len = ALIGN(len, mtd->writesize);
782 /* Preset the buffer with 0xff */
783 memset(buf, 0xff, len);
784 /* Pattern is located at the begin of first page */
785 memcpy(buf, td->pattern, td->len);
788 len = (size_t)(numblocks >> sft);
789 /* Make it page aligned! */
790 len = ALIGN(len, mtd->writesize);
791 /* Preset the buffer with 0xff */
792 memset(buf, 0xff, len +
793 (len >> this->page_shift)* mtd->oobsize);
796 /* Pattern is located in oob area of first page */
797 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
800 if (td->options & NAND_BBT_VERSION)
801 buf[ooboffs + td->veroffs] = td->version[chip];
803 /* Walk through the memory table */
804 for (i = 0; i < numblocks; i++) {
806 int sftcnt = (i << (3 - sft)) & sftmsk;
807 dat = bbt_get_entry(this, chip * numblocks + i);
808 /* Do not store the reserved bbt blocks! */
809 buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
812 memset(&einfo, 0, sizeof(einfo));
815 einfo.len = 1 << this->bbt_erase_shift;
816 res = nand_erase_nand(mtd, &einfo, 1);
820 res = scan_write_bbt(mtd, to, len, buf,
821 td->options & NAND_BBT_NO_OOB ? NULL :
826 pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
827 (unsigned long long)to, td->version[chip]);
829 /* Mark it as used */
830 td->pages[chip] = page;
835 pr_warn("nand_bbt: error while writing bad block table %d\n", res);
840 * nand_memory_bbt - [GENERIC] create a memory based bad block table
841 * @mtd: MTD device structure
842 * @bd: descriptor for the good/bad block search pattern
844 * The function creates a memory based bbt by scanning the device for
845 * manufacturer / software marked good / bad blocks.
847 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
849 struct nand_chip *this = mtd->priv;
851 return create_bbt(mtd, this->buffers->databuf, bd, -1);
855 * check_create - [GENERIC] create and write bbt(s) if necessary
856 * @mtd: MTD device structure
857 * @buf: temporary buffer
858 * @bd: descriptor for the good/bad block search pattern
860 * The function checks the results of the previous call to read_bbt and creates
861 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
862 * for the chip/device. Update is necessary if one of the tables is missing or
863 * the version nr. of one table is less than the other.
865 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
867 int i, chips, writeops, create, chipsel, res, res2;
868 struct nand_chip *this = mtd->priv;
869 struct nand_bbt_descr *td = this->bbt_td;
870 struct nand_bbt_descr *md = this->bbt_md;
871 struct nand_bbt_descr *rd, *rd2;
873 /* Do we have a bbt per chip? */
874 if (td->options & NAND_BBT_PERCHIP)
875 chips = this->numchips;
879 for (i = 0; i < chips; i++) {
885 /* Per chip or per device? */
886 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
887 /* Mirrored table available? */
889 if (td->pages[i] == -1 && md->pages[i] == -1) {
892 } else if (td->pages[i] == -1) {
895 } else if (md->pages[i] == -1) {
898 } else if (td->version[i] == md->version[i]) {
900 if (!(td->options & NAND_BBT_VERSION))
902 } else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
910 if (td->pages[i] == -1) {
919 /* Create the bad block table by scanning the device? */
920 if (!(td->options & NAND_BBT_CREATE))
923 /* Create the table in memory by scanning the chip(s) */
924 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
925 create_bbt(mtd, buf, bd, chipsel);
932 /* Read back first? */
934 res = read_abs_bbt(mtd, buf, rd, chipsel);
935 if (mtd_is_eccerr(res)) {
936 /* Mark table as invalid */
943 /* If they weren't versioned, read both */
945 res2 = read_abs_bbt(mtd, buf, rd2, chipsel);
946 if (mtd_is_eccerr(res2)) {
947 /* Mark table as invalid */
955 /* Scrub the flash table(s)? */
956 if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
959 /* Update version numbers before writing */
961 td->version[i] = max(td->version[i], md->version[i]);
962 md->version[i] = td->version[i];
965 /* Write the bad block table to the device? */
966 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
967 res = write_bbt(mtd, buf, td, md, chipsel);
972 /* Write the mirror bad block table to the device? */
973 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
974 res = write_bbt(mtd, buf, md, td, chipsel);
983 * mark_bbt_regions - [GENERIC] mark the bad block table regions
984 * @mtd: MTD device structure
985 * @td: bad block table descriptor
987 * The bad block table regions are marked as "bad" to prevent accidental
988 * erasures / writes. The regions are identified by the mark 0x02.
990 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
992 struct nand_chip *this = mtd->priv;
993 int i, j, chips, block, nrblocks, update;
996 /* Do we have a bbt per chip? */
997 if (td->options & NAND_BBT_PERCHIP) {
998 chips = this->numchips;
999 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
1002 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1005 for (i = 0; i < chips; i++) {
1006 if ((td->options & NAND_BBT_ABSPAGE) ||
1007 !(td->options & NAND_BBT_WRITE)) {
1008 if (td->pages[i] == -1)
1010 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1011 oldval = bbt_get_entry(this, block);
1012 bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1013 if ((oldval != BBT_BLOCK_RESERVED) &&
1014 td->reserved_block_code)
1015 nand_update_bbt(mtd, (loff_t)block <<
1016 this->bbt_erase_shift);
1020 if (td->options & NAND_BBT_LASTBLOCK)
1021 block = ((i + 1) * nrblocks) - td->maxblocks;
1023 block = i * nrblocks;
1024 for (j = 0; j < td->maxblocks; j++) {
1025 oldval = bbt_get_entry(this, block);
1026 bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1027 if (oldval != BBT_BLOCK_RESERVED)
1032 * If we want reserved blocks to be recorded to flash, and some
1033 * new ones have been marked, then we need to update the stored
1034 * bbts. This should only happen once.
1036 if (update && td->reserved_block_code)
1037 nand_update_bbt(mtd, (loff_t)(block - 1) <<
1038 this->bbt_erase_shift);
1043 * verify_bbt_descr - verify the bad block description
1044 * @mtd: MTD device structure
1045 * @bd: the table to verify
1047 * This functions performs a few sanity checks on the bad block description
1050 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1052 struct nand_chip *this = mtd->priv;
1060 pattern_len = bd->len;
1061 bits = bd->options & NAND_BBT_NRBITS_MSK;
1063 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1064 !(this->bbt_options & NAND_BBT_USE_FLASH));
1067 if (bd->options & NAND_BBT_VERSION)
1070 if (bd->options & NAND_BBT_NO_OOB) {
1071 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1072 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1074 if (bd->options & NAND_BBT_VERSION)
1075 BUG_ON(bd->veroffs != bd->len);
1076 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1079 if (bd->options & NAND_BBT_PERCHIP)
1080 table_size = this->chipsize >> this->bbt_erase_shift;
1082 table_size = mtd->size >> this->bbt_erase_shift;
1085 if (bd->options & NAND_BBT_NO_OOB)
1086 table_size += pattern_len;
1087 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1091 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1092 * @mtd: MTD device structure
1093 * @bd: descriptor for the good/bad block search pattern
1095 * The function checks, if a bad block table(s) is/are already available. If
1096 * not it scans the device for manufacturer marked good / bad blocks and writes
1097 * the bad block table(s) to the selected place.
1099 * The bad block table memory is allocated here. It must be freed by calling
1100 * the nand_free_bbt function.
1102 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1104 struct nand_chip *this = mtd->priv;
1107 struct nand_bbt_descr *td = this->bbt_td;
1108 struct nand_bbt_descr *md = this->bbt_md;
1110 len = mtd->size >> (this->bbt_erase_shift + 2);
1112 * Allocate memory (2bit per block) and clear the memory bad block
1115 this->bbt = kzalloc(len, GFP_KERNEL);
1120 * If no primary table decriptor is given, scan the device to build a
1121 * memory based bad block table.
1124 if ((res = nand_memory_bbt(mtd, bd))) {
1125 pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1131 verify_bbt_descr(mtd, td);
1132 verify_bbt_descr(mtd, md);
1134 /* Allocate a temporary buffer for one eraseblock incl. oob */
1135 len = (1 << this->bbt_erase_shift);
1136 len += (len >> this->page_shift) * mtd->oobsize;
1144 /* Is the bbt at a given page? */
1145 if (td->options & NAND_BBT_ABSPAGE) {
1146 read_abs_bbts(mtd, buf, td, md);
1148 /* Search the bad block table using a pattern in oob */
1149 search_read_bbts(mtd, buf, td, md);
1152 res = check_create(mtd, buf, bd);
1154 /* Prevent the bbt regions from erasing / writing */
1155 mark_bbt_region(mtd, td);
1157 mark_bbt_region(mtd, md);
1164 * nand_update_bbt - update bad block table(s)
1165 * @mtd: MTD device structure
1166 * @offs: the offset of the newly marked block
1168 * The function updates the bad block table(s).
1170 static int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1172 struct nand_chip *this = mtd->priv;
1176 struct nand_bbt_descr *td = this->bbt_td;
1177 struct nand_bbt_descr *md = this->bbt_md;
1179 if (!this->bbt || !td)
1182 /* Allocate a temporary buffer for one eraseblock incl. oob */
1183 len = (1 << this->bbt_erase_shift);
1184 len += (len >> this->page_shift) * mtd->oobsize;
1185 buf = kmalloc(len, GFP_KERNEL);
1189 /* Do we have a bbt per chip? */
1190 if (td->options & NAND_BBT_PERCHIP) {
1191 chip = (int)(offs >> this->chip_shift);
1198 td->version[chip]++;
1200 md->version[chip]++;
1202 /* Write the bad block table to the device? */
1203 if (td->options & NAND_BBT_WRITE) {
1204 res = write_bbt(mtd, buf, td, md, chipsel);
1208 /* Write the mirror bad block table to the device? */
1209 if (md && (md->options & NAND_BBT_WRITE)) {
1210 res = write_bbt(mtd, buf, md, td, chipsel);
1219 * Define some generic bad / good block scan pattern which are used
1220 * while scanning a device for factory marked good / bad blocks.
1222 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1224 /* Generic flash bbt descriptors */
1225 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1226 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1228 static struct nand_bbt_descr bbt_main_descr = {
1229 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1230 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1234 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1235 .pattern = bbt_pattern
1238 static struct nand_bbt_descr bbt_mirror_descr = {
1239 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1240 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1244 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1245 .pattern = mirror_pattern
1248 static struct nand_bbt_descr bbt_main_no_oob_descr = {
1249 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1250 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1254 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1255 .pattern = bbt_pattern
1258 static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
1259 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1260 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1264 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1265 .pattern = mirror_pattern
1268 #define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1270 * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1271 * @this: NAND chip to create descriptor for
1273 * This function allocates and initializes a nand_bbt_descr for BBM detection
1274 * based on the properties of @this. The new descriptor is stored in
1275 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1276 * passed to this function.
1278 static int nand_create_badblock_pattern(struct nand_chip *this)
1280 struct nand_bbt_descr *bd;
1281 if (this->badblock_pattern) {
1282 pr_warn("Bad block pattern already allocated; not replacing\n");
1285 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1288 bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1289 bd->offs = this->badblockpos;
1290 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1291 bd->pattern = scan_ff_pattern;
1292 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1293 this->badblock_pattern = bd;
1298 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1299 * @mtd: MTD device structure
1301 * This function selects the default bad block table support for the device and
1302 * calls the nand_scan_bbt function.
1304 int nand_default_bbt(struct mtd_info *mtd)
1306 struct nand_chip *this = mtd->priv;
1308 /* Is a flash based bad block table requested? */
1309 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1310 /* Use the default pattern descriptors */
1311 if (!this->bbt_td) {
1312 if (this->bbt_options & NAND_BBT_NO_OOB) {
1313 this->bbt_td = &bbt_main_no_oob_descr;
1314 this->bbt_md = &bbt_mirror_no_oob_descr;
1316 this->bbt_td = &bbt_main_descr;
1317 this->bbt_md = &bbt_mirror_descr;
1321 this->bbt_td = NULL;
1322 this->bbt_md = NULL;
1325 if (!this->badblock_pattern)
1326 nand_create_badblock_pattern(this);
1328 return nand_scan_bbt(mtd, this->badblock_pattern);
1332 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1333 * @mtd: MTD device structure
1334 * @offs: offset in the device
1335 * @allowbbt: allow access to bad block table region
1337 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1339 struct nand_chip *this = mtd->priv;
1342 block = (int)(offs >> this->bbt_erase_shift);
1343 res = bbt_get_entry(this, block);
1345 pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: "
1346 "(block %d) 0x%02x\n",
1347 (unsigned int)offs, block, res);
1350 case BBT_BLOCK_GOOD:
1352 case BBT_BLOCK_WORN:
1354 case BBT_BLOCK_RESERVED:
1355 return allowbbt ? 0 : 1;
1361 * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1362 * @mtd: MTD device structure
1363 * @offs: offset of the bad block
1365 int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs)
1367 struct nand_chip *this = mtd->priv;
1370 block = (int)(offs >> this->bbt_erase_shift);
1372 /* Mark bad block in memory */
1373 bbt_mark_entry(this, block, BBT_BLOCK_WORN);
1375 /* Update flash-based bad block table */
1376 if (this->bbt_options & NAND_BBT_USE_FLASH)
1377 ret = nand_update_bbt(mtd, offs);
1382 EXPORT_SYMBOL(nand_scan_bbt);