3 * Bad block table support for the NAND driver
5 * Copyright © 2004 Thomas Gleixner (tglx@linutronix.de)
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
13 * When nand_scan_bbt is called, then it tries to find the bad block table
14 * depending on the options in the BBT descriptor(s). If no flash based BBT
15 * (NAND_BBT_USE_FLASH) is specified then the device is scanned for factory
16 * marked good / bad blocks. This information is used to create a memory BBT.
17 * Once a new bad block is discovered then the "factory" information is updated
19 * If a flash based BBT is specified then the function first tries to find the
20 * BBT on flash. If a BBT is found then the contents are read and the memory
21 * based BBT is created. If a mirrored BBT is selected then the mirror is
22 * searched too and the versions are compared. If the mirror has a greater
23 * version number, then the mirror BBT is used to build the memory based BBT.
24 * If the tables are not versioned, then we "or" the bad block information.
25 * If one of the BBTs is out of date or does not exist it is (re)created.
26 * If no BBT exists at all then the device is scanned for factory marked
27 * good / bad blocks and the bad block tables are created.
29 * For manufacturer created BBTs like the one found on M-SYS DOC devices
30 * the BBT is searched and read but never created
32 * The auto generated bad block table is located in the last good blocks
33 * of the device. The table is mirrored, so it can be updated eventually.
34 * The table is marked in the OOB area with an ident pattern and a version
35 * number which indicates which of both tables is more up to date. If the NAND
36 * controller needs the complete OOB area for the ECC information then the
37 * option NAND_BBT_NO_OOB should be used (along with NAND_BBT_USE_FLASH, of
38 * course): it moves the ident pattern and the version byte into the data area
39 * and the OOB area will remain untouched.
41 * The table uses 2 bits per block
43 * 00b: block is factory marked bad
44 * 01b, 10b: block is marked bad due to wear
46 * The memory bad block table uses the following scheme:
48 * 01b: block is marked bad due to wear
49 * 10b: block is reserved (to protect the bbt area)
50 * 11b: block is factory marked bad
52 * Multichip devices like DOC store the bad block info per floor.
54 * Following assumptions are made:
55 * - bbts start at a page boundary, if autolocated on a block boundary
56 * - the space necessary for a bbt in FLASH does not exceed a block boundary
62 #include <linux/compat.h>
63 #include <linux/mtd/mtd.h>
64 #include <linux/mtd/bbm.h>
65 #include <linux/mtd/nand.h>
66 #include <linux/bitops.h>
67 #include <linux/string.h>
69 #define BBT_BLOCK_GOOD 0x00
70 #define BBT_BLOCK_WORN 0x01
71 #define BBT_BLOCK_RESERVED 0x02
72 #define BBT_BLOCK_FACTORY_BAD 0x03
74 #define BBT_ENTRY_MASK 0x03
75 #define BBT_ENTRY_SHIFT 2
77 static int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
79 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
81 uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
82 entry >>= (block & BBT_ENTRY_MASK) * 2;
83 return entry & BBT_ENTRY_MASK;
86 static inline void bbt_mark_entry(struct nand_chip *chip, int block,
89 uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);
90 chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;
93 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
95 if (memcmp(buf, td->pattern, td->len))
101 * check_pattern - [GENERIC] check if a pattern is in the buffer
102 * @buf: the buffer to search
103 * @len: the length of buffer to search
104 * @paglen: the pagelength
105 * @td: search pattern descriptor
107 * Check for a pattern at the given place. Used to search bad block tables and
108 * good / bad block identifiers.
110 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
112 if (td->options & NAND_BBT_NO_OOB)
113 return check_pattern_no_oob(buf, td);
115 /* Compare the pattern */
116 if (memcmp(buf + paglen + td->offs, td->pattern, td->len))
123 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
124 * @buf: the buffer to search
125 * @td: search pattern descriptor
127 * Check for a pattern at the given place. Used to search bad block tables and
128 * good / bad block identifiers. Same as check_pattern, but no optional empty
131 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
133 /* Compare the pattern */
134 if (memcmp(buf + td->offs, td->pattern, td->len))
140 * add_marker_len - compute the length of the marker in data area
141 * @td: BBT descriptor used for computation
143 * The length will be 0 if the marker is located in OOB area.
145 static u32 add_marker_len(struct nand_bbt_descr *td)
149 if (!(td->options & NAND_BBT_NO_OOB))
153 if (td->options & NAND_BBT_VERSION)
159 * read_bbt - [GENERIC] Read the bad block table starting from page
160 * @mtd: MTD device structure
161 * @buf: temporary buffer
162 * @page: the starting page
163 * @num: the number of bbt descriptors to read
164 * @td: the bbt describtion table
165 * @offs: block number offset in the table
167 * Read the bad block table starting from page.
169 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
170 struct nand_bbt_descr *td, int offs)
172 int res, ret = 0, i, j, act = 0;
173 struct nand_chip *this = mtd_to_nand(mtd);
174 size_t retlen, len, totlen;
176 int bits = td->options & NAND_BBT_NRBITS_MSK;
177 uint8_t msk = (uint8_t)((1 << bits) - 1);
179 int reserved_block_code = td->reserved_block_code;
181 totlen = (num * bits) >> 3;
182 marker_len = add_marker_len(td);
183 from = ((loff_t)page) << this->page_shift;
186 len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
189 * In case the BBT marker is not in the OOB area it
190 * will be just in the first page.
196 res = mtd_read(mtd, from, len, &retlen, buf);
198 if (mtd_is_eccerr(res)) {
199 pr_info("nand_bbt: ECC error in BBT at 0x%012llx\n",
200 from & ~mtd->writesize);
202 } else if (mtd_is_bitflip(res)) {
203 pr_info("nand_bbt: corrected error in BBT at 0x%012llx\n",
204 from & ~mtd->writesize);
207 pr_info("nand_bbt: error reading BBT\n");
213 for (i = 0; i < len; i++) {
214 uint8_t dat = buf[i];
215 for (j = 0; j < 8; j += bits, act++) {
216 uint8_t tmp = (dat >> j) & msk;
219 if (reserved_block_code && (tmp == reserved_block_code)) {
220 pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
221 (loff_t)(offs + act) <<
222 this->bbt_erase_shift);
223 bbt_mark_entry(this, offs + act,
225 mtd->ecc_stats.bbtblocks++;
229 * Leave it for now, if it's matured we can
230 * move this message to pr_debug.
232 pr_info("nand_read_bbt: bad block at 0x%012llx\n",
233 (loff_t)(offs + act) <<
234 this->bbt_erase_shift);
235 /* Factory marked bad or worn out? */
237 bbt_mark_entry(this, offs + act,
238 BBT_BLOCK_FACTORY_BAD);
240 bbt_mark_entry(this, offs + act,
242 mtd->ecc_stats.badblocks++;
252 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
253 * @mtd: MTD device structure
254 * @buf: temporary buffer
255 * @td: descriptor for the bad block table
256 * @chip: read the table for a specific chip, -1 read all chips; applies only if
257 * NAND_BBT_PERCHIP option is set
259 * Read the bad block table for all chips starting at a given page. We assume
260 * that the bbt bits are in consecutive order.
262 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
264 struct nand_chip *this = mtd_to_nand(mtd);
267 if (td->options & NAND_BBT_PERCHIP) {
269 for (i = 0; i < this->numchips; i++) {
270 if (chip == -1 || chip == i)
271 res = read_bbt(mtd, buf, td->pages[i],
272 this->chipsize >> this->bbt_erase_shift,
276 offs += this->chipsize >> this->bbt_erase_shift;
279 res = read_bbt(mtd, buf, td->pages[0],
280 mtd->size >> this->bbt_erase_shift, td, 0);
287 /* BBT marker is in the first page, no OOB */
288 static int scan_read_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
289 struct nand_bbt_descr *td)
295 if (td->options & NAND_BBT_VERSION)
298 return mtd_read(mtd, offs, len, &retlen, buf);
302 * scan_read_oob - [GENERIC] Scan data+OOB region to buffer
303 * @mtd: MTD device structure
304 * @buf: temporary buffer
305 * @offs: offset at which to scan
306 * @len: length of data region to read
308 * Scan read data from data+OOB. May traverse multiple pages, interleaving
309 * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest"
310 * ECC condition (error or bitflip). May quit on the first (non-ECC) error.
312 static int scan_read_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
315 struct mtd_oob_ops ops;
318 ops.mode = MTD_OPS_PLACE_OOB;
320 ops.ooblen = mtd->oobsize;
324 ops.len = min(len, (size_t)mtd->writesize);
325 ops.oobbuf = buf + ops.len;
327 res = mtd_read_oob(mtd, offs, &ops);
329 if (!mtd_is_bitflip_or_eccerr(res))
331 else if (mtd_is_eccerr(res) || !ret)
335 buf += mtd->oobsize + mtd->writesize;
336 len -= mtd->writesize;
337 offs += mtd->writesize;
342 static int scan_read(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
343 size_t len, struct nand_bbt_descr *td)
345 if (td->options & NAND_BBT_NO_OOB)
346 return scan_read_data(mtd, buf, offs, td);
348 return scan_read_oob(mtd, buf, offs, len);
351 /* Scan write data with oob to flash */
352 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
353 uint8_t *buf, uint8_t *oob)
355 struct mtd_oob_ops ops;
357 ops.mode = MTD_OPS_PLACE_OOB;
359 ops.ooblen = mtd->oobsize;
364 return mtd_write_oob(mtd, offs, &ops);
367 static u32 bbt_get_ver_offs(struct mtd_info *mtd, struct nand_bbt_descr *td)
369 u32 ver_offs = td->veroffs;
371 if (!(td->options & NAND_BBT_NO_OOB))
372 ver_offs += mtd->writesize;
377 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
378 * @mtd: MTD device structure
379 * @buf: temporary buffer
380 * @td: descriptor for the bad block table
381 * @md: descriptor for the bad block table mirror
383 * Read the bad block table(s) for all chips starting at a given page. We
384 * assume that the bbt bits are in consecutive order.
386 static void read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
387 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
389 struct nand_chip *this = mtd_to_nand(mtd);
391 /* Read the primary version, if available */
392 if (td->options & NAND_BBT_VERSION) {
393 scan_read(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
395 td->version[0] = buf[bbt_get_ver_offs(mtd, td)];
396 pr_info("Bad block table at page %d, version 0x%02X\n",
397 td->pages[0], td->version[0]);
400 /* Read the mirror version, if available */
401 if (md && (md->options & NAND_BBT_VERSION)) {
402 scan_read(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
404 md->version[0] = buf[bbt_get_ver_offs(mtd, md)];
405 pr_info("Bad block table at page %d, version 0x%02X\n",
406 md->pages[0], md->version[0]);
410 /* Scan a given block partially */
411 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
412 loff_t offs, uint8_t *buf, int numpages)
414 struct mtd_oob_ops ops;
417 ops.ooblen = mtd->oobsize;
421 ops.mode = MTD_OPS_PLACE_OOB;
423 for (j = 0; j < numpages; j++) {
425 * Read the full oob until read_oob is fixed to handle single
426 * byte reads for 16 bit buswidth.
428 ret = mtd_read_oob(mtd, offs, &ops);
429 /* Ignore ECC errors when checking for BBM */
430 if (ret && !mtd_is_bitflip_or_eccerr(ret))
433 if (check_short_pattern(buf, bd))
436 offs += mtd->writesize;
442 * create_bbt - [GENERIC] Create a bad block table by scanning the device
443 * @mtd: MTD device structure
444 * @buf: temporary buffer
445 * @bd: descriptor for the good/bad block search pattern
446 * @chip: create the table for a specific chip, -1 read all chips; applies only
447 * if NAND_BBT_PERCHIP option is set
449 * Create a bad block table by scanning the device for the given good/bad block
452 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
453 struct nand_bbt_descr *bd, int chip)
455 struct nand_chip *this = mtd_to_nand(mtd);
456 int i, numblocks, numpages;
460 pr_info("Scanning device for bad blocks\n");
462 if (bd->options & NAND_BBT_SCAN2NDPAGE)
468 numblocks = mtd->size >> this->bbt_erase_shift;
472 if (chip >= this->numchips) {
473 pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
474 chip + 1, this->numchips);
477 numblocks = this->chipsize >> this->bbt_erase_shift;
478 startblock = chip * numblocks;
479 numblocks += startblock;
480 from = (loff_t)startblock << this->bbt_erase_shift;
483 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
484 from += mtd->erasesize - (mtd->writesize * numpages);
486 for (i = startblock; i < numblocks; i++) {
489 BUG_ON(bd->options & NAND_BBT_NO_OOB);
491 ret = scan_block_fast(mtd, bd, from, buf, numpages);
496 bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
497 pr_warn("Bad eraseblock %d at 0x%012llx\n",
498 i, (unsigned long long)from);
499 mtd->ecc_stats.badblocks++;
502 from += (1 << this->bbt_erase_shift);
508 * search_bbt - [GENERIC] scan the device for a specific bad block table
509 * @mtd: MTD device structure
510 * @buf: temporary buffer
511 * @td: descriptor for the bad block table
513 * Read the bad block table by searching for a given ident pattern. Search is
514 * preformed either from the beginning up or from the end of the device
515 * downwards. The search starts always at the start of a block. If the option
516 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
517 * the bad block information of this chip. This is necessary to provide support
518 * for certain DOC devices.
520 * The bbt ident pattern resides in the oob area of the first page in a block.
522 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
524 struct nand_chip *this = mtd_to_nand(mtd);
526 int startblock, block, dir;
527 int scanlen = mtd->writesize + mtd->oobsize;
529 int blocktopage = this->bbt_erase_shift - this->page_shift;
531 /* Search direction top -> down? */
532 if (td->options & NAND_BBT_LASTBLOCK) {
533 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
540 /* Do we have a bbt per chip? */
541 if (td->options & NAND_BBT_PERCHIP) {
542 chips = this->numchips;
543 bbtblocks = this->chipsize >> this->bbt_erase_shift;
544 startblock &= bbtblocks - 1;
547 bbtblocks = mtd->size >> this->bbt_erase_shift;
550 for (i = 0; i < chips; i++) {
551 /* Reset version information */
554 /* Scan the maximum number of blocks */
555 for (block = 0; block < td->maxblocks; block++) {
557 int actblock = startblock + dir * block;
558 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
560 /* Read first page */
561 scan_read(mtd, buf, offs, mtd->writesize, td);
562 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
563 td->pages[i] = actblock << blocktopage;
564 if (td->options & NAND_BBT_VERSION) {
565 offs = bbt_get_ver_offs(mtd, td);
566 td->version[i] = buf[offs];
571 startblock += this->chipsize >> this->bbt_erase_shift;
573 /* Check, if we found a bbt for each requested chip */
574 for (i = 0; i < chips; i++) {
575 if (td->pages[i] == -1)
576 pr_warn("Bad block table not found for chip %d\n", i);
578 pr_info("Bad block table found at page %d, version 0x%02X\n",
579 td->pages[i], td->version[i]);
585 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
586 * @mtd: MTD device structure
587 * @buf: temporary buffer
588 * @td: descriptor for the bad block table
589 * @md: descriptor for the bad block table mirror
591 * Search and read the bad block table(s).
593 static void search_read_bbts(struct mtd_info *mtd, uint8_t *buf,
594 struct nand_bbt_descr *td,
595 struct nand_bbt_descr *md)
597 /* Search the primary table */
598 search_bbt(mtd, buf, td);
600 /* Search the mirror table */
602 search_bbt(mtd, buf, md);
606 * write_bbt - [GENERIC] (Re)write the bad block table
607 * @mtd: MTD device structure
608 * @buf: temporary buffer
609 * @td: descriptor for the bad block table
610 * @md: descriptor for the bad block table mirror
611 * @chipsel: selector for a specific chip, -1 for all
613 * (Re)write the bad block table.
615 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
616 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
619 struct nand_chip *this = mtd_to_nand(mtd);
620 struct erase_info einfo;
621 int i, res, chip = 0;
622 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
623 int nrchips, pageoffs, ooboffs;
625 uint8_t rcode = td->reserved_block_code;
626 size_t retlen, len = 0;
628 struct mtd_oob_ops ops;
630 ops.ooblen = mtd->oobsize;
633 ops.mode = MTD_OPS_PLACE_OOB;
637 /* Write bad block table per chip rather than per device? */
638 if (td->options & NAND_BBT_PERCHIP) {
639 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
640 /* Full device write or specific chip? */
642 nrchips = this->numchips;
644 nrchips = chipsel + 1;
648 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
652 /* Loop through the chips */
653 for (; chip < nrchips; chip++) {
655 * There was already a version of the table, reuse the page
656 * This applies for absolute placement too, as we have the
657 * page nr. in td->pages.
659 if (td->pages[chip] != -1) {
660 page = td->pages[chip];
665 * Automatic placement of the bad block table. Search direction
668 if (td->options & NAND_BBT_LASTBLOCK) {
669 startblock = numblocks * (chip + 1) - 1;
672 startblock = chip * numblocks;
676 for (i = 0; i < td->maxblocks; i++) {
677 int block = startblock + dir * i;
678 /* Check, if the block is bad */
679 switch (bbt_get_entry(this, block)) {
681 case BBT_BLOCK_FACTORY_BAD:
685 (this->bbt_erase_shift - this->page_shift);
686 /* Check, if the block is used by the mirror table */
687 if (!md || md->pages[chip] != page)
690 pr_err("No space left to write bad block table\n");
694 /* Set up shift count and masks for the flash table */
695 bits = td->options & NAND_BBT_NRBITS_MSK;
698 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
701 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
704 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
707 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
710 default: return -EINVAL;
713 to = ((loff_t)page) << this->page_shift;
715 /* Must we save the block contents? */
716 if (td->options & NAND_BBT_SAVECONTENT) {
717 /* Make it block aligned */
718 to &= ~(((loff_t)1 << this->bbt_erase_shift) - 1);
719 len = 1 << this->bbt_erase_shift;
720 res = mtd_read(mtd, to, len, &retlen, buf);
723 pr_info("nand_bbt: error reading block for writing the bad block table\n");
726 pr_warn("nand_bbt: ECC error while reading block for writing bad block table\n");
729 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
730 ops.oobbuf = &buf[len];
731 res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
732 if (res < 0 || ops.oobretlen != ops.ooblen)
735 /* Calc the byte offset in the buffer */
736 pageoffs = page - (int)(to >> this->page_shift);
737 offs = pageoffs << this->page_shift;
738 /* Preset the bbt area with 0xff */
739 memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
740 ooboffs = len + (pageoffs * mtd->oobsize);
742 } else if (td->options & NAND_BBT_NO_OOB) {
745 /* The version byte */
746 if (td->options & NAND_BBT_VERSION)
749 len = (size_t)(numblocks >> sft);
751 /* Make it page aligned! */
752 len = ALIGN(len, mtd->writesize);
753 /* Preset the buffer with 0xff */
754 memset(buf, 0xff, len);
755 /* Pattern is located at the begin of first page */
756 memcpy(buf, td->pattern, td->len);
759 len = (size_t)(numblocks >> sft);
760 /* Make it page aligned! */
761 len = ALIGN(len, mtd->writesize);
762 /* Preset the buffer with 0xff */
763 memset(buf, 0xff, len +
764 (len >> this->page_shift)* mtd->oobsize);
767 /* Pattern is located in oob area of first page */
768 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
771 if (td->options & NAND_BBT_VERSION)
772 buf[ooboffs + td->veroffs] = td->version[chip];
774 /* Walk through the memory table */
775 for (i = 0; i < numblocks; i++) {
777 int sftcnt = (i << (3 - sft)) & sftmsk;
778 dat = bbt_get_entry(this, chip * numblocks + i);
779 /* Do not store the reserved bbt blocks! */
780 buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
783 memset(&einfo, 0, sizeof(einfo));
786 einfo.len = 1 << this->bbt_erase_shift;
787 res = nand_erase_nand(mtd, &einfo, 1);
791 res = scan_write_bbt(mtd, to, len, buf,
792 td->options & NAND_BBT_NO_OOB ? NULL :
797 pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
798 (unsigned long long)to, td->version[chip]);
800 /* Mark it as used */
801 td->pages[chip] = page;
806 pr_warn("nand_bbt: error while writing bad block table %d\n", res);
811 * nand_memory_bbt - [GENERIC] create a memory based bad block table
812 * @mtd: MTD device structure
813 * @bd: descriptor for the good/bad block search pattern
815 * The function creates a memory based bbt by scanning the device for
816 * manufacturer / software marked good / bad blocks.
818 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
820 struct nand_chip *this = mtd_to_nand(mtd);
822 return create_bbt(mtd, this->buffers->databuf, bd, -1);
826 * check_create - [GENERIC] create and write bbt(s) if necessary
827 * @mtd: MTD device structure
828 * @buf: temporary buffer
829 * @bd: descriptor for the good/bad block search pattern
831 * The function checks the results of the previous call to read_bbt and creates
832 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
833 * for the chip/device. Update is necessary if one of the tables is missing or
834 * the version nr. of one table is less than the other.
836 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
838 int i, chips, writeops, create, chipsel, res, res2;
839 struct nand_chip *this = mtd_to_nand(mtd);
840 struct nand_bbt_descr *td = this->bbt_td;
841 struct nand_bbt_descr *md = this->bbt_md;
842 struct nand_bbt_descr *rd, *rd2;
844 /* Do we have a bbt per chip? */
845 if (td->options & NAND_BBT_PERCHIP)
846 chips = this->numchips;
850 for (i = 0; i < chips; i++) {
856 /* Per chip or per device? */
857 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
858 /* Mirrored table available? */
860 if (td->pages[i] == -1 && md->pages[i] == -1) {
863 } else if (td->pages[i] == -1) {
866 } else if (md->pages[i] == -1) {
869 } else if (td->version[i] == md->version[i]) {
871 if (!(td->options & NAND_BBT_VERSION))
873 } else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
881 if (td->pages[i] == -1) {
890 /* Create the bad block table by scanning the device? */
891 if (!(td->options & NAND_BBT_CREATE))
894 /* Create the table in memory by scanning the chip(s) */
895 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
896 create_bbt(mtd, buf, bd, chipsel);
903 /* Read back first? */
905 res = read_abs_bbt(mtd, buf, rd, chipsel);
906 if (mtd_is_eccerr(res)) {
907 /* Mark table as invalid */
914 /* If they weren't versioned, read both */
916 res2 = read_abs_bbt(mtd, buf, rd2, chipsel);
917 if (mtd_is_eccerr(res2)) {
918 /* Mark table as invalid */
926 /* Scrub the flash table(s)? */
927 if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
930 /* Update version numbers before writing */
932 td->version[i] = max(td->version[i], md->version[i]);
933 md->version[i] = td->version[i];
936 /* Write the bad block table to the device? */
937 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
938 res = write_bbt(mtd, buf, td, md, chipsel);
943 /* Write the mirror bad block table to the device? */
944 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
945 res = write_bbt(mtd, buf, md, td, chipsel);
954 * mark_bbt_regions - [GENERIC] mark the bad block table regions
955 * @mtd: MTD device structure
956 * @td: bad block table descriptor
958 * The bad block table regions are marked as "bad" to prevent accidental
959 * erasures / writes. The regions are identified by the mark 0x02.
961 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
963 struct nand_chip *this = mtd_to_nand(mtd);
964 int i, j, chips, block, nrblocks, update;
967 /* Do we have a bbt per chip? */
968 if (td->options & NAND_BBT_PERCHIP) {
969 chips = this->numchips;
970 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
973 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
976 for (i = 0; i < chips; i++) {
977 if ((td->options & NAND_BBT_ABSPAGE) ||
978 !(td->options & NAND_BBT_WRITE)) {
979 if (td->pages[i] == -1)
981 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
982 oldval = bbt_get_entry(this, block);
983 bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
984 if ((oldval != BBT_BLOCK_RESERVED) &&
985 td->reserved_block_code)
986 nand_update_bbt(mtd, (loff_t)block <<
987 this->bbt_erase_shift);
991 if (td->options & NAND_BBT_LASTBLOCK)
992 block = ((i + 1) * nrblocks) - td->maxblocks;
994 block = i * nrblocks;
995 for (j = 0; j < td->maxblocks; j++) {
996 oldval = bbt_get_entry(this, block);
997 bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
998 if (oldval != BBT_BLOCK_RESERVED)
1003 * If we want reserved blocks to be recorded to flash, and some
1004 * new ones have been marked, then we need to update the stored
1005 * bbts. This should only happen once.
1007 if (update && td->reserved_block_code)
1008 nand_update_bbt(mtd, (loff_t)(block - 1) <<
1009 this->bbt_erase_shift);
1014 * verify_bbt_descr - verify the bad block description
1015 * @mtd: MTD device structure
1016 * @bd: the table to verify
1018 * This functions performs a few sanity checks on the bad block description
1021 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1023 struct nand_chip *this = mtd_to_nand(mtd);
1031 pattern_len = bd->len;
1032 bits = bd->options & NAND_BBT_NRBITS_MSK;
1034 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1035 !(this->bbt_options & NAND_BBT_USE_FLASH));
1038 if (bd->options & NAND_BBT_VERSION)
1041 if (bd->options & NAND_BBT_NO_OOB) {
1042 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1043 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1045 if (bd->options & NAND_BBT_VERSION)
1046 BUG_ON(bd->veroffs != bd->len);
1047 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1050 if (bd->options & NAND_BBT_PERCHIP)
1051 table_size = this->chipsize >> this->bbt_erase_shift;
1053 table_size = mtd->size >> this->bbt_erase_shift;
1056 if (bd->options & NAND_BBT_NO_OOB)
1057 table_size += pattern_len;
1058 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1062 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1063 * @mtd: MTD device structure
1064 * @bd: descriptor for the good/bad block search pattern
1066 * The function checks, if a bad block table(s) is/are already available. If
1067 * not it scans the device for manufacturer marked good / bad blocks and writes
1068 * the bad block table(s) to the selected place.
1070 * The bad block table memory is allocated here. It must be freed by calling
1071 * the nand_free_bbt function.
1073 static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1075 struct nand_chip *this = mtd_to_nand(mtd);
1078 struct nand_bbt_descr *td = this->bbt_td;
1079 struct nand_bbt_descr *md = this->bbt_md;
1081 len = (mtd->size >> (this->bbt_erase_shift + 2)) ? : 1;
1083 * Allocate memory (2bit per block) and clear the memory bad block
1086 this->bbt = kzalloc(len, GFP_KERNEL);
1091 * If no primary table decriptor is given, scan the device to build a
1092 * memory based bad block table.
1095 if ((res = nand_memory_bbt(mtd, bd))) {
1096 pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1101 verify_bbt_descr(mtd, td);
1102 verify_bbt_descr(mtd, md);
1104 /* Allocate a temporary buffer for one eraseblock incl. oob */
1105 len = (1 << this->bbt_erase_shift);
1106 len += (len >> this->page_shift) * mtd->oobsize;
1113 /* Is the bbt at a given page? */
1114 if (td->options & NAND_BBT_ABSPAGE) {
1115 read_abs_bbts(mtd, buf, td, md);
1117 /* Search the bad block table using a pattern in oob */
1118 search_read_bbts(mtd, buf, td, md);
1121 res = check_create(mtd, buf, bd);
1125 /* Prevent the bbt regions from erasing / writing */
1126 mark_bbt_region(mtd, td);
1128 mark_bbt_region(mtd, md);
1140 * nand_update_bbt - update bad block table(s)
1141 * @mtd: MTD device structure
1142 * @offs: the offset of the newly marked block
1144 * The function updates the bad block table(s).
1146 static int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1148 struct nand_chip *this = mtd_to_nand(mtd);
1152 struct nand_bbt_descr *td = this->bbt_td;
1153 struct nand_bbt_descr *md = this->bbt_md;
1155 if (!this->bbt || !td)
1158 /* Allocate a temporary buffer for one eraseblock incl. oob */
1159 len = (1 << this->bbt_erase_shift);
1160 len += (len >> this->page_shift) * mtd->oobsize;
1161 buf = kmalloc(len, GFP_KERNEL);
1165 /* Do we have a bbt per chip? */
1166 if (td->options & NAND_BBT_PERCHIP) {
1167 chip = (int)(offs >> this->chip_shift);
1174 td->version[chip]++;
1176 md->version[chip]++;
1178 /* Write the bad block table to the device? */
1179 if (td->options & NAND_BBT_WRITE) {
1180 res = write_bbt(mtd, buf, td, md, chipsel);
1184 /* Write the mirror bad block table to the device? */
1185 if (md && (md->options & NAND_BBT_WRITE)) {
1186 res = write_bbt(mtd, buf, md, td, chipsel);
1195 * Define some generic bad / good block scan pattern which are used
1196 * while scanning a device for factory marked good / bad blocks.
1198 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1200 /* Generic flash bbt descriptors */
1201 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1202 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1204 static struct nand_bbt_descr bbt_main_descr = {
1205 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1206 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1210 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1211 .pattern = bbt_pattern
1214 static struct nand_bbt_descr bbt_mirror_descr = {
1215 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1216 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1220 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1221 .pattern = mirror_pattern
1224 static struct nand_bbt_descr bbt_main_no_oob_descr = {
1225 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1226 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1230 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1231 .pattern = bbt_pattern
1234 static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
1235 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1236 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1240 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1241 .pattern = mirror_pattern
1244 #define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1246 * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1247 * @this: NAND chip to create descriptor for
1249 * This function allocates and initializes a nand_bbt_descr for BBM detection
1250 * based on the properties of @this. The new descriptor is stored in
1251 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1252 * passed to this function.
1254 static int nand_create_badblock_pattern(struct nand_chip *this)
1256 struct nand_bbt_descr *bd;
1257 if (this->badblock_pattern) {
1258 pr_warn("Bad block pattern already allocated; not replacing\n");
1261 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1264 bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1265 bd->offs = this->badblockpos;
1266 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1267 bd->pattern = scan_ff_pattern;
1268 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1269 this->badblock_pattern = bd;
1274 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1275 * @mtd: MTD device structure
1277 * This function selects the default bad block table support for the device and
1278 * calls the nand_scan_bbt function.
1280 int nand_default_bbt(struct mtd_info *mtd)
1282 struct nand_chip *this = mtd_to_nand(mtd);
1285 /* Is a flash based bad block table requested? */
1286 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1287 /* Use the default pattern descriptors */
1288 if (!this->bbt_td) {
1289 if (this->bbt_options & NAND_BBT_NO_OOB) {
1290 this->bbt_td = &bbt_main_no_oob_descr;
1291 this->bbt_md = &bbt_mirror_no_oob_descr;
1293 this->bbt_td = &bbt_main_descr;
1294 this->bbt_md = &bbt_mirror_descr;
1298 this->bbt_td = NULL;
1299 this->bbt_md = NULL;
1302 if (!this->badblock_pattern) {
1303 ret = nand_create_badblock_pattern(this);
1308 return nand_scan_bbt(mtd, this->badblock_pattern);
1312 * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
1313 * @mtd: MTD device structure
1314 * @offs: offset in the device
1316 int nand_isreserved_bbt(struct mtd_info *mtd, loff_t offs)
1318 struct nand_chip *this = mtd_to_nand(mtd);
1321 block = (int)(offs >> this->bbt_erase_shift);
1322 return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;
1326 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1327 * @mtd: MTD device structure
1328 * @offs: offset in the device
1329 * @allowbbt: allow access to bad block table region
1331 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1333 struct nand_chip *this = mtd_to_nand(mtd);
1336 block = (int)(offs >> this->bbt_erase_shift);
1337 res = bbt_get_entry(this, block);
1339 pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1340 (unsigned int)offs, block, res);
1343 case BBT_BLOCK_GOOD:
1345 case BBT_BLOCK_WORN:
1347 case BBT_BLOCK_RESERVED:
1348 return allowbbt ? 0 : 1;
1354 * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1355 * @mtd: MTD device structure
1356 * @offs: offset of the bad block
1358 int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs)
1360 struct nand_chip *this = mtd_to_nand(mtd);
1363 block = (int)(offs >> this->bbt_erase_shift);
1365 /* Mark bad block in memory */
1366 bbt_mark_entry(this, block, BBT_BLOCK_WORN);
1368 /* Update flash-based bad block table */
1369 if (this->bbt_options & NAND_BBT_USE_FLASH)
1370 ret = nand_update_bbt(mtd, offs);