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27 * If one of the BBTs is out of date or does not exist it is (re)created.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
62 #include <linux/slab.h>
63 #include <linux/types.h>
64 #include <linux/mtd/mtd.h>
65 #include <linux/mtd/bbm.h>
66 #include <linux/mtd/nand.h>
67 #include <linux/mtd/nand_ecc.h>
68 #include <linux/bitops.h>
69 #include <linux/delay.h>
70 #include <linux/vmalloc.h>
71 #include <linux/export.h>
72 #include <linux/string.h>
74 #define BBT_BLOCK_GOOD 0x00
75 #define BBT_BLOCK_WORN 0x01
76 #define BBT_BLOCK_RESERVED 0x02
77 #define BBT_BLOCK_FACTORY_BAD 0x03
79 #define BBT_ENTRY_MASK 0x03
80 #define BBT_ENTRY_SHIFT 2
82 static int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
84 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
86 uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
87 entry >>= (block & BBT_ENTRY_MASK) * 2;
88 return entry & BBT_ENTRY_MASK;
91 static inline void bbt_mark_entry(struct nand_chip *chip, int block,
94 uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);
95 chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;
98 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
100 if (memcmp(buf, td->pattern, td->len))
106 * check_pattern - [GENERIC] check if a pattern is in the buffer
107 * @buf: the buffer to search
108 * @len: the length of buffer to search
109 * @paglen: the pagelength
110 * @td: search pattern descriptor
112 * Check for a pattern at the given place. Used to search bad block tables and
113 * good / bad block identifiers.
115 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
117 if (td->options & NAND_BBT_NO_OOB)
118 return check_pattern_no_oob(buf, td);
120 /* Compare the pattern */
121 if (memcmp(buf + paglen + td->offs, td->pattern, td->len))
128 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
129 * @buf: the buffer to search
130 * @td: search pattern descriptor
132 * Check for a pattern at the given place. Used to search bad block tables and
133 * good / bad block identifiers. Same as check_pattern, but no optional empty
136 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
138 /* Compare the pattern */
139 if (memcmp(buf + td->offs, td->pattern, td->len))
145 * add_marker_len - compute the length of the marker in data area
146 * @td: BBT descriptor used for computation
148 * The length will be 0 if the marker is located in OOB area.
150 static u32 add_marker_len(struct nand_bbt_descr *td)
154 if (!(td->options & NAND_BBT_NO_OOB))
158 if (td->options & NAND_BBT_VERSION)
164 * read_bbt - [GENERIC] Read the bad block table starting from page
165 * @mtd: MTD device structure
166 * @buf: temporary buffer
167 * @page: the starting page
168 * @num: the number of bbt descriptors to read
169 * @td: the bbt describtion table
170 * @offs: block number offset in the table
172 * Read the bad block table starting from page.
174 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
175 struct nand_bbt_descr *td, int offs)
177 int res, ret = 0, i, j, act = 0;
178 struct nand_chip *this = mtd->priv;
179 size_t retlen, len, totlen;
181 int bits = td->options & NAND_BBT_NRBITS_MSK;
182 uint8_t msk = (uint8_t)((1 << bits) - 1);
184 int reserved_block_code = td->reserved_block_code;
186 totlen = (num * bits) >> 3;
187 marker_len = add_marker_len(td);
188 from = ((loff_t)page) << this->page_shift;
191 len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
194 * In case the BBT marker is not in the OOB area it
195 * will be just in the first page.
201 res = mtd_read(mtd, from, len, &retlen, buf);
203 if (mtd_is_eccerr(res)) {
204 pr_info("nand_bbt: ECC error in BBT at "
205 "0x%012llx\n", from & ~mtd->writesize);
207 } else if (mtd_is_bitflip(res)) {
208 pr_info("nand_bbt: corrected error in BBT at "
209 "0x%012llx\n", from & ~mtd->writesize);
212 pr_info("nand_bbt: error reading BBT\n");
218 for (i = 0; i < len; i++) {
219 uint8_t dat = buf[i];
220 for (j = 0; j < 8; j += bits, act++) {
221 uint8_t tmp = (dat >> j) & msk;
224 if (reserved_block_code && (tmp == reserved_block_code)) {
225 pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
226 (loff_t)(offs + act) <<
227 this->bbt_erase_shift);
228 bbt_mark_entry(this, offs + act,
230 mtd->ecc_stats.bbtblocks++;
234 * Leave it for now, if it's matured we can
235 * move this message to pr_debug.
237 pr_info("nand_read_bbt: bad block at 0x%012llx\n",
238 (loff_t)(offs + act) <<
239 this->bbt_erase_shift);
240 /* Factory marked bad or worn out? */
242 bbt_mark_entry(this, offs + act,
243 BBT_BLOCK_FACTORY_BAD);
245 bbt_mark_entry(this, offs + act,
247 mtd->ecc_stats.badblocks++;
257 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
258 * @mtd: MTD device structure
259 * @buf: temporary buffer
260 * @td: descriptor for the bad block table
261 * @chip: read the table for a specific chip, -1 read all chips; applies only if
262 * NAND_BBT_PERCHIP option is set
264 * Read the bad block table for all chips starting at a given page. We assume
265 * that the bbt bits are in consecutive order.
267 static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
269 struct nand_chip *this = mtd->priv;
272 if (td->options & NAND_BBT_PERCHIP) {
274 for (i = 0; i < this->numchips; i++) {
275 if (chip == -1 || chip == i)
276 res = read_bbt(mtd, buf, td->pages[i],
277 this->chipsize >> this->bbt_erase_shift,
281 offs += this->chipsize >> this->bbt_erase_shift;
284 res = read_bbt(mtd, buf, td->pages[0],
285 mtd->size >> this->bbt_erase_shift, td, 0);
292 /* BBT marker is in the first page, no OOB */
293 static int scan_read_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
294 struct nand_bbt_descr *td)
300 if (td->options & NAND_BBT_VERSION)
303 return mtd_read(mtd, offs, len, &retlen, buf);
307 * scan_read_oob - [GENERIC] Scan data+OOB region to buffer
308 * @mtd: MTD device structure
309 * @buf: temporary buffer
310 * @offs: offset at which to scan
311 * @len: length of data region to read
313 * Scan read data from data+OOB. May traverse multiple pages, interleaving
314 * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest"
315 * ECC condition (error or bitflip). May quit on the first (non-ECC) error.
317 static int scan_read_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
320 struct mtd_oob_ops ops;
323 ops.mode = MTD_OPS_PLACE_OOB;
325 ops.ooblen = mtd->oobsize;
329 ops.len = min(len, (size_t)mtd->writesize);
330 ops.oobbuf = buf + ops.len;
332 res = mtd_read_oob(mtd, offs, &ops);
334 if (!mtd_is_bitflip_or_eccerr(res))
336 else if (mtd_is_eccerr(res) || !ret)
340 buf += mtd->oobsize + mtd->writesize;
341 len -= mtd->writesize;
342 offs += mtd->writesize;
347 static int scan_read(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
348 size_t len, struct nand_bbt_descr *td)
350 if (td->options & NAND_BBT_NO_OOB)
351 return scan_read_data(mtd, buf, offs, td);
353 return scan_read_oob(mtd, buf, offs, len);
356 /* Scan write data with oob to flash */
357 static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
358 uint8_t *buf, uint8_t *oob)
360 struct mtd_oob_ops ops;
362 ops.mode = MTD_OPS_PLACE_OOB;
364 ops.ooblen = mtd->oobsize;
369 return mtd_write_oob(mtd, offs, &ops);
372 static u32 bbt_get_ver_offs(struct mtd_info *mtd, struct nand_bbt_descr *td)
374 u32 ver_offs = td->veroffs;
376 if (!(td->options & NAND_BBT_NO_OOB))
377 ver_offs += mtd->writesize;
382 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
383 * @mtd: MTD device structure
384 * @buf: temporary buffer
385 * @td: descriptor for the bad block table
386 * @md: descriptor for the bad block table mirror
388 * Read the bad block table(s) for all chips starting at a given page. We
389 * assume that the bbt bits are in consecutive order.
391 static void read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
392 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
394 struct nand_chip *this = mtd->priv;
396 /* Read the primary version, if available */
397 if (td->options & NAND_BBT_VERSION) {
398 scan_read(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
400 td->version[0] = buf[bbt_get_ver_offs(mtd, td)];
401 pr_info("Bad block table at page %d, version 0x%02X\n",
402 td->pages[0], td->version[0]);
405 /* Read the mirror version, if available */
406 if (md && (md->options & NAND_BBT_VERSION)) {
407 scan_read(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
409 md->version[0] = buf[bbt_get_ver_offs(mtd, md)];
410 pr_info("Bad block table at page %d, version 0x%02X\n",
411 md->pages[0], md->version[0]);
415 /* Scan a given block partially */
416 static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
417 loff_t offs, uint8_t *buf, int numpages)
419 struct mtd_oob_ops ops;
422 ops.ooblen = mtd->oobsize;
426 ops.mode = MTD_OPS_PLACE_OOB;
428 for (j = 0; j < numpages; j++) {
430 * Read the full oob until read_oob is fixed to handle single
431 * byte reads for 16 bit buswidth.
433 ret = mtd_read_oob(mtd, offs, &ops);
434 /* Ignore ECC errors when checking for BBM */
435 if (ret && !mtd_is_bitflip_or_eccerr(ret))
438 if (check_short_pattern(buf, bd))
441 offs += mtd->writesize;
447 * create_bbt - [GENERIC] Create a bad block table by scanning the device
448 * @mtd: MTD device structure
449 * @buf: temporary buffer
450 * @bd: descriptor for the good/bad block search pattern
451 * @chip: create the table for a specific chip, -1 read all chips; applies only
452 * if NAND_BBT_PERCHIP option is set
454 * Create a bad block table by scanning the device for the given good/bad block
457 static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
458 struct nand_bbt_descr *bd, int chip)
460 struct nand_chip *this = mtd->priv;
461 int i, numblocks, numpages;
465 pr_info("Scanning device for bad blocks\n");
467 if (bd->options & NAND_BBT_SCAN2NDPAGE)
473 numblocks = mtd->size >> this->bbt_erase_shift;
477 if (chip >= this->numchips) {
478 pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
479 chip + 1, this->numchips);
482 numblocks = this->chipsize >> this->bbt_erase_shift;
483 startblock = chip * numblocks;
484 numblocks += startblock;
485 from = (loff_t)startblock << this->bbt_erase_shift;
488 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
489 from += mtd->erasesize - (mtd->writesize * numpages);
491 for (i = startblock; i < numblocks; i++) {
494 BUG_ON(bd->options & NAND_BBT_NO_OOB);
496 ret = scan_block_fast(mtd, bd, from, buf, numpages);
501 bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
502 pr_warn("Bad eraseblock %d at 0x%012llx\n",
503 i, (unsigned long long)from);
504 mtd->ecc_stats.badblocks++;
507 from += (1 << this->bbt_erase_shift);
513 * search_bbt - [GENERIC] scan the device for a specific bad block table
514 * @mtd: MTD device structure
515 * @buf: temporary buffer
516 * @td: descriptor for the bad block table
518 * Read the bad block table by searching for a given ident pattern. Search is
519 * preformed either from the beginning up or from the end of the device
520 * downwards. The search starts always at the start of a block. If the option
521 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
522 * the bad block information of this chip. This is necessary to provide support
523 * for certain DOC devices.
525 * The bbt ident pattern resides in the oob area of the first page in a block.
527 static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
529 struct nand_chip *this = mtd->priv;
531 int startblock, block, dir;
532 int scanlen = mtd->writesize + mtd->oobsize;
534 int blocktopage = this->bbt_erase_shift - this->page_shift;
536 /* Search direction top -> down? */
537 if (td->options & NAND_BBT_LASTBLOCK) {
538 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
545 /* Do we have a bbt per chip? */
546 if (td->options & NAND_BBT_PERCHIP) {
547 chips = this->numchips;
548 bbtblocks = this->chipsize >> this->bbt_erase_shift;
549 startblock &= bbtblocks - 1;
552 bbtblocks = mtd->size >> this->bbt_erase_shift;
555 for (i = 0; i < chips; i++) {
556 /* Reset version information */
559 /* Scan the maximum number of blocks */
560 for (block = 0; block < td->maxblocks; block++) {
562 int actblock = startblock + dir * block;
563 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
565 /* Read first page */
566 scan_read(mtd, buf, offs, mtd->writesize, td);
567 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
568 td->pages[i] = actblock << blocktopage;
569 if (td->options & NAND_BBT_VERSION) {
570 offs = bbt_get_ver_offs(mtd, td);
571 td->version[i] = buf[offs];
576 startblock += this->chipsize >> this->bbt_erase_shift;
578 /* Check, if we found a bbt for each requested chip */
579 for (i = 0; i < chips; i++) {
580 if (td->pages[i] == -1)
581 pr_warn("Bad block table not found for chip %d\n", i);
583 pr_info("Bad block table found at page %d, version "
584 "0x%02X\n", td->pages[i], td->version[i]);
590 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
591 * @mtd: MTD device structure
592 * @buf: temporary buffer
593 * @td: descriptor for the bad block table
594 * @md: descriptor for the bad block table mirror
596 * Search and read the bad block table(s).
598 static void search_read_bbts(struct mtd_info *mtd, uint8_t *buf,
599 struct nand_bbt_descr *td,
600 struct nand_bbt_descr *md)
602 /* Search the primary table */
603 search_bbt(mtd, buf, td);
605 /* Search the mirror table */
607 search_bbt(mtd, buf, md);
611 * write_bbt - [GENERIC] (Re)write the bad block table
612 * @mtd: MTD device structure
613 * @buf: temporary buffer
614 * @td: descriptor for the bad block table
615 * @md: descriptor for the bad block table mirror
616 * @chipsel: selector for a specific chip, -1 for all
618 * (Re)write the bad block table.
620 static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
621 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
624 struct nand_chip *this = mtd->priv;
625 struct erase_info einfo;
626 int i, res, chip = 0;
627 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
628 int nrchips, pageoffs, ooboffs;
630 uint8_t rcode = td->reserved_block_code;
631 size_t retlen, len = 0;
633 struct mtd_oob_ops ops;
635 ops.ooblen = mtd->oobsize;
638 ops.mode = MTD_OPS_PLACE_OOB;
642 /* Write bad block table per chip rather than per device? */
643 if (td->options & NAND_BBT_PERCHIP) {
644 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
645 /* Full device write or specific chip? */
647 nrchips = this->numchips;
649 nrchips = chipsel + 1;
653 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
657 /* Loop through the chips */
658 for (; chip < nrchips; chip++) {
660 * There was already a version of the table, reuse the page
661 * This applies for absolute placement too, as we have the
662 * page nr. in td->pages.
664 if (td->pages[chip] != -1) {
665 page = td->pages[chip];
670 * Automatic placement of the bad block table. Search direction
673 if (td->options & NAND_BBT_LASTBLOCK) {
674 startblock = numblocks * (chip + 1) - 1;
677 startblock = chip * numblocks;
681 for (i = 0; i < td->maxblocks; i++) {
682 int block = startblock + dir * i;
683 /* Check, if the block is bad */
684 switch (bbt_get_entry(this, block)) {
686 case BBT_BLOCK_FACTORY_BAD:
690 (this->bbt_erase_shift - this->page_shift);
691 /* Check, if the block is used by the mirror table */
692 if (!md || md->pages[chip] != page)
695 pr_err("No space left to write bad block table\n");
699 /* Set up shift count and masks for the flash table */
700 bits = td->options & NAND_BBT_NRBITS_MSK;
703 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
706 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
709 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
712 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
715 default: return -EINVAL;
718 to = ((loff_t)page) << this->page_shift;
720 /* Must we save the block contents? */
721 if (td->options & NAND_BBT_SAVECONTENT) {
722 /* Make it block aligned */
723 to &= ~((loff_t)((1 << this->bbt_erase_shift) - 1));
724 len = 1 << this->bbt_erase_shift;
725 res = mtd_read(mtd, to, len, &retlen, buf);
728 pr_info("nand_bbt: error reading block "
729 "for writing the bad block table\n");
732 pr_warn("nand_bbt: ECC error while reading "
733 "block for writing bad block table\n");
736 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
737 ops.oobbuf = &buf[len];
738 res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
739 if (res < 0 || ops.oobretlen != ops.ooblen)
742 /* Calc the byte offset in the buffer */
743 pageoffs = page - (int)(to >> this->page_shift);
744 offs = pageoffs << this->page_shift;
745 /* Preset the bbt area with 0xff */
746 memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
747 ooboffs = len + (pageoffs * mtd->oobsize);
749 } else if (td->options & NAND_BBT_NO_OOB) {
752 /* The version byte */
753 if (td->options & NAND_BBT_VERSION)
756 len = (size_t)(numblocks >> sft);
758 /* Make it page aligned! */
759 len = ALIGN(len, mtd->writesize);
760 /* Preset the buffer with 0xff */
761 memset(buf, 0xff, len);
762 /* Pattern is located at the begin of first page */
763 memcpy(buf, td->pattern, td->len);
766 len = (size_t)(numblocks >> sft);
767 /* Make it page aligned! */
768 len = ALIGN(len, mtd->writesize);
769 /* Preset the buffer with 0xff */
770 memset(buf, 0xff, len +
771 (len >> this->page_shift)* mtd->oobsize);
774 /* Pattern is located in oob area of first page */
775 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
778 if (td->options & NAND_BBT_VERSION)
779 buf[ooboffs + td->veroffs] = td->version[chip];
781 /* Walk through the memory table */
782 for (i = 0; i < numblocks; i++) {
784 int sftcnt = (i << (3 - sft)) & sftmsk;
785 dat = bbt_get_entry(this, chip * numblocks + i);
786 /* Do not store the reserved bbt blocks! */
787 buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
790 memset(&einfo, 0, sizeof(einfo));
793 einfo.len = 1 << this->bbt_erase_shift;
794 res = nand_erase_nand(mtd, &einfo, 1);
798 res = scan_write_bbt(mtd, to, len, buf,
799 td->options & NAND_BBT_NO_OOB ? NULL :
804 pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
805 (unsigned long long)to, td->version[chip]);
807 /* Mark it as used */
808 td->pages[chip] = page;
813 pr_warn("nand_bbt: error while writing bad block table %d\n", res);
818 * nand_memory_bbt - [GENERIC] create a memory based bad block table
819 * @mtd: MTD device structure
820 * @bd: descriptor for the good/bad block search pattern
822 * The function creates a memory based bbt by scanning the device for
823 * manufacturer / software marked good / bad blocks.
825 static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
827 struct nand_chip *this = mtd->priv;
829 return create_bbt(mtd, this->buffers->databuf, bd, -1);
833 * check_create - [GENERIC] create and write bbt(s) if necessary
834 * @mtd: MTD device structure
835 * @buf: temporary buffer
836 * @bd: descriptor for the good/bad block search pattern
838 * The function checks the results of the previous call to read_bbt and creates
839 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
840 * for the chip/device. Update is necessary if one of the tables is missing or
841 * the version nr. of one table is less than the other.
843 static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
845 int i, chips, writeops, create, chipsel, res, res2;
846 struct nand_chip *this = mtd->priv;
847 struct nand_bbt_descr *td = this->bbt_td;
848 struct nand_bbt_descr *md = this->bbt_md;
849 struct nand_bbt_descr *rd, *rd2;
851 /* Do we have a bbt per chip? */
852 if (td->options & NAND_BBT_PERCHIP)
853 chips = this->numchips;
857 for (i = 0; i < chips; i++) {
863 /* Per chip or per device? */
864 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
865 /* Mirrored table available? */
867 if (td->pages[i] == -1 && md->pages[i] == -1) {
870 } else if (td->pages[i] == -1) {
873 } else if (md->pages[i] == -1) {
876 } else if (td->version[i] == md->version[i]) {
878 if (!(td->options & NAND_BBT_VERSION))
880 } else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
888 if (td->pages[i] == -1) {
897 /* Create the bad block table by scanning the device? */
898 if (!(td->options & NAND_BBT_CREATE))
901 /* Create the table in memory by scanning the chip(s) */
902 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
903 create_bbt(mtd, buf, bd, chipsel);
910 /* Read back first? */
912 res = read_abs_bbt(mtd, buf, rd, chipsel);
913 if (mtd_is_eccerr(res)) {
914 /* Mark table as invalid */
921 /* If they weren't versioned, read both */
923 res2 = read_abs_bbt(mtd, buf, rd2, chipsel);
924 if (mtd_is_eccerr(res2)) {
925 /* Mark table as invalid */
933 /* Scrub the flash table(s)? */
934 if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
937 /* Update version numbers before writing */
939 td->version[i] = max(td->version[i], md->version[i]);
940 md->version[i] = td->version[i];
943 /* Write the bad block table to the device? */
944 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
945 res = write_bbt(mtd, buf, td, md, chipsel);
950 /* Write the mirror bad block table to the device? */
951 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
952 res = write_bbt(mtd, buf, md, td, chipsel);
961 * mark_bbt_regions - [GENERIC] mark the bad block table regions
962 * @mtd: MTD device structure
963 * @td: bad block table descriptor
965 * The bad block table regions are marked as "bad" to prevent accidental
966 * erasures / writes. The regions are identified by the mark 0x02.
968 static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
970 struct nand_chip *this = mtd->priv;
971 int i, j, chips, block, nrblocks, update;
974 /* Do we have a bbt per chip? */
975 if (td->options & NAND_BBT_PERCHIP) {
976 chips = this->numchips;
977 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
980 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
983 for (i = 0; i < chips; i++) {
984 if ((td->options & NAND_BBT_ABSPAGE) ||
985 !(td->options & NAND_BBT_WRITE)) {
986 if (td->pages[i] == -1)
988 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
989 oldval = bbt_get_entry(this, block);
990 bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
991 if ((oldval != BBT_BLOCK_RESERVED) &&
992 td->reserved_block_code)
993 nand_update_bbt(mtd, (loff_t)block <<
994 this->bbt_erase_shift);
998 if (td->options & NAND_BBT_LASTBLOCK)
999 block = ((i + 1) * nrblocks) - td->maxblocks;
1001 block = i * nrblocks;
1002 for (j = 0; j < td->maxblocks; j++) {
1003 oldval = bbt_get_entry(this, block);
1004 bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1005 if (oldval != BBT_BLOCK_RESERVED)
1010 * If we want reserved blocks to be recorded to flash, and some
1011 * new ones have been marked, then we need to update the stored
1012 * bbts. This should only happen once.
1014 if (update && td->reserved_block_code)
1015 nand_update_bbt(mtd, (loff_t)(block - 1) <<
1016 this->bbt_erase_shift);
1021 * verify_bbt_descr - verify the bad block description
1022 * @mtd: MTD device structure
1023 * @bd: the table to verify
1025 * This functions performs a few sanity checks on the bad block description
1028 static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1030 struct nand_chip *this = mtd->priv;
1038 pattern_len = bd->len;
1039 bits = bd->options & NAND_BBT_NRBITS_MSK;
1041 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1042 !(this->bbt_options & NAND_BBT_USE_FLASH));
1045 if (bd->options & NAND_BBT_VERSION)
1048 if (bd->options & NAND_BBT_NO_OOB) {
1049 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1050 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1052 if (bd->options & NAND_BBT_VERSION)
1053 BUG_ON(bd->veroffs != bd->len);
1054 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1057 if (bd->options & NAND_BBT_PERCHIP)
1058 table_size = this->chipsize >> this->bbt_erase_shift;
1060 table_size = mtd->size >> this->bbt_erase_shift;
1063 if (bd->options & NAND_BBT_NO_OOB)
1064 table_size += pattern_len;
1065 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1069 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1070 * @mtd: MTD device structure
1071 * @bd: descriptor for the good/bad block search pattern
1073 * The function checks, if a bad block table(s) is/are already available. If
1074 * not it scans the device for manufacturer marked good / bad blocks and writes
1075 * the bad block table(s) to the selected place.
1077 * The bad block table memory is allocated here. It must be freed by calling
1078 * the nand_free_bbt function.
1080 int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1082 struct nand_chip *this = mtd->priv;
1085 struct nand_bbt_descr *td = this->bbt_td;
1086 struct nand_bbt_descr *md = this->bbt_md;
1088 len = mtd->size >> (this->bbt_erase_shift + 2);
1090 * Allocate memory (2bit per block) and clear the memory bad block
1093 this->bbt = kzalloc(len, GFP_KERNEL);
1098 * If no primary table decriptor is given, scan the device to build a
1099 * memory based bad block table.
1102 if ((res = nand_memory_bbt(mtd, bd))) {
1103 pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1109 verify_bbt_descr(mtd, td);
1110 verify_bbt_descr(mtd, md);
1112 /* Allocate a temporary buffer for one eraseblock incl. oob */
1113 len = (1 << this->bbt_erase_shift);
1114 len += (len >> this->page_shift) * mtd->oobsize;
1122 /* Is the bbt at a given page? */
1123 if (td->options & NAND_BBT_ABSPAGE) {
1124 read_abs_bbts(mtd, buf, td, md);
1126 /* Search the bad block table using a pattern in oob */
1127 search_read_bbts(mtd, buf, td, md);
1130 res = check_create(mtd, buf, bd);
1132 /* Prevent the bbt regions from erasing / writing */
1133 mark_bbt_region(mtd, td);
1135 mark_bbt_region(mtd, md);
1142 * nand_update_bbt - update bad block table(s)
1143 * @mtd: MTD device structure
1144 * @offs: the offset of the newly marked block
1146 * The function updates the bad block table(s).
1148 static int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1150 struct nand_chip *this = mtd->priv;
1154 struct nand_bbt_descr *td = this->bbt_td;
1155 struct nand_bbt_descr *md = this->bbt_md;
1157 if (!this->bbt || !td)
1160 /* Allocate a temporary buffer for one eraseblock incl. oob */
1161 len = (1 << this->bbt_erase_shift);
1162 len += (len >> this->page_shift) * mtd->oobsize;
1163 buf = kmalloc(len, GFP_KERNEL);
1167 /* Do we have a bbt per chip? */
1168 if (td->options & NAND_BBT_PERCHIP) {
1169 chip = (int)(offs >> this->chip_shift);
1176 td->version[chip]++;
1178 md->version[chip]++;
1180 /* Write the bad block table to the device? */
1181 if (td->options & NAND_BBT_WRITE) {
1182 res = write_bbt(mtd, buf, td, md, chipsel);
1186 /* Write the mirror bad block table to the device? */
1187 if (md && (md->options & NAND_BBT_WRITE)) {
1188 res = write_bbt(mtd, buf, md, td, chipsel);
1197 * Define some generic bad / good block scan pattern which are used
1198 * while scanning a device for factory marked good / bad blocks.
1200 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1202 /* Generic flash bbt descriptors */
1203 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1204 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1206 static struct nand_bbt_descr bbt_main_descr = {
1207 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1208 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1212 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1213 .pattern = bbt_pattern
1216 static struct nand_bbt_descr bbt_mirror_descr = {
1217 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1218 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1222 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1223 .pattern = mirror_pattern
1226 static struct nand_bbt_descr bbt_main_no_oob_descr = {
1227 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1228 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1232 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1233 .pattern = bbt_pattern
1236 static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
1237 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1238 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1242 .maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1243 .pattern = mirror_pattern
1246 #define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1248 * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1249 * @this: NAND chip to create descriptor for
1251 * This function allocates and initializes a nand_bbt_descr for BBM detection
1252 * based on the properties of @this. The new descriptor is stored in
1253 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1254 * passed to this function.
1256 static int nand_create_badblock_pattern(struct nand_chip *this)
1258 struct nand_bbt_descr *bd;
1259 if (this->badblock_pattern) {
1260 pr_warn("Bad block pattern already allocated; not replacing\n");
1263 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1266 bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1267 bd->offs = this->badblockpos;
1268 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1269 bd->pattern = scan_ff_pattern;
1270 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1271 this->badblock_pattern = bd;
1276 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1277 * @mtd: MTD device structure
1279 * This function selects the default bad block table support for the device and
1280 * calls the nand_scan_bbt function.
1282 int nand_default_bbt(struct mtd_info *mtd)
1284 struct nand_chip *this = mtd->priv;
1287 /* Is a flash based bad block table requested? */
1288 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1289 /* Use the default pattern descriptors */
1290 if (!this->bbt_td) {
1291 if (this->bbt_options & NAND_BBT_NO_OOB) {
1292 this->bbt_td = &bbt_main_no_oob_descr;
1293 this->bbt_md = &bbt_mirror_no_oob_descr;
1295 this->bbt_td = &bbt_main_descr;
1296 this->bbt_md = &bbt_mirror_descr;
1300 this->bbt_td = NULL;
1301 this->bbt_md = NULL;
1304 if (!this->badblock_pattern) {
1305 ret = nand_create_badblock_pattern(this);
1310 return nand_scan_bbt(mtd, this->badblock_pattern);
1314 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1315 * @mtd: MTD device structure
1316 * @offs: offset in the device
1317 * @allowbbt: allow access to bad block table region
1319 int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1321 struct nand_chip *this = mtd->priv;
1324 block = (int)(offs >> this->bbt_erase_shift);
1325 res = bbt_get_entry(this, block);
1327 pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: "
1328 "(block %d) 0x%02x\n",
1329 (unsigned int)offs, block, res);
1332 case BBT_BLOCK_GOOD:
1334 case BBT_BLOCK_WORN:
1336 case BBT_BLOCK_RESERVED:
1337 return allowbbt ? 0 : 1;
1343 * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1344 * @mtd: MTD device structure
1345 * @offs: offset of the bad block
1347 int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs)
1349 struct nand_chip *this = mtd->priv;
1352 block = (int)(offs >> this->bbt_erase_shift);
1354 /* Mark bad block in memory */
1355 bbt_mark_entry(this, block, BBT_BLOCK_WORN);
1357 /* Update flash-based bad block table */
1358 if (this->bbt_options & NAND_BBT_USE_FLASH)
1359 ret = nand_update_bbt(mtd, offs);
1364 EXPORT_SYMBOL(nand_scan_bbt);