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1/*
2 * drivers/mtd/nand_bbt.c
3 *
4 * Overview:
5 * Bad block table support for the NAND driver
6 *
7 * Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
8 *
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.
12 *
13 * Description:
14 *
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
20 * on the device.
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 than 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27 * If one of the BBTs is out of date or does not exist it is (re)created.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.
30 *
31 * For manufacturer created BBTs like the one found on M-SYS DOC devices
32 * the BBT is searched and read but never created
33 *
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.
42 *
43 * The table uses 2 bits per block
44 * 11b: block is good
45 * 00b: block is factory marked bad
46 * 01b, 10b: block is marked bad due to wear
47 *
48 * The memory bad block table uses the following scheme:
49 * 00b: block is good
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
53 *
54 * Multichip devices like DOC store the bad block info per floor.
55 *
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
59 *
60 */
61
62#include <linux/slab.h>
63#include <linux/types.h>
64#include <linux/mtd/mtd.h>
65#include <linux/mtd/nand.h>
66#include <linux/mtd/nand_ecc.h>
67#include <linux/bitops.h>
68#include <linux/delay.h>
69#include <linux/vmalloc.h>
70#include <linux/export.h>
71
72static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
73{
74 int ret;
75
76 ret = memcmp(buf, td->pattern, td->len);
77 if (!ret)
78 return ret;
79 return -1;
80}
81
82/**
83 * check_pattern - [GENERIC] check if a pattern is in the buffer
84 * @buf: the buffer to search
85 * @len: the length of buffer to search
86 * @paglen: the pagelength
87 * @td: search pattern descriptor
88 *
89 * Check for a pattern at the given place. Used to search bad block tables and
90 * good / bad block identifiers. If the SCAN_EMPTY option is set then check, if
91 * all bytes except the pattern area contain 0xff.
92 */
93static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
94{
95 int i, end = 0;
96 uint8_t *p = buf;
97
98 if (td->options & NAND_BBT_NO_OOB)
99 return check_pattern_no_oob(buf, td);
100
101 end = paglen + td->offs;
102 if (td->options & NAND_BBT_SCANEMPTY) {
103 for (i = 0; i < end; i++) {
104 if (p[i] != 0xff)
105 return -1;
106 }
107 }
108 p += end;
109
110 /* Compare the pattern */
111 if (memcmp(p, td->pattern, td->len))
112 return -1;
113
114 if (td->options & NAND_BBT_SCANEMPTY) {
115 p += td->len;
116 end += td->len;
117 for (i = end; i < len; i++) {
118 if (*p++ != 0xff)
119 return -1;
120 }
121 }
122 return 0;
123}
124
125/**
126 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
127 * @buf: the buffer to search
128 * @td: search pattern descriptor
129 *
130 * Check for a pattern at the given place. Used to search bad block tables and
131 * good / bad block identifiers. Same as check_pattern, but no optional empty
132 * check.
133 */
134static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
135{
136 int i;
137 uint8_t *p = buf;
138
139 /* Compare the pattern */
140 for (i = 0; i < td->len; i++) {
141 if (p[td->offs + i] != td->pattern[i])
142 return -1;
143 }
144 return 0;
145}
146
147/**
148 * add_marker_len - compute the length of the marker in data area
149 * @td: BBT descriptor used for computation
150 *
151 * The length will be 0 if the marker is located in OOB area.
152 */
153static u32 add_marker_len(struct nand_bbt_descr *td)
154{
155 u32 len;
156
157 if (!(td->options & NAND_BBT_NO_OOB))
158 return 0;
159
160 len = td->len;
161 if (td->options & NAND_BBT_VERSION)
162 len++;
163 return len;
164}
165
166/**
167 * read_bbt - [GENERIC] Read the bad block table starting from page
168 * @mtd: MTD device structure
169 * @buf: temporary buffer
170 * @page: the starting page
171 * @num: the number of bbt descriptors to read
172 * @td: the bbt describtion table
173 * @offs: offset in the memory table
174 *
175 * Read the bad block table starting from page.
176 */
177static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
178 struct nand_bbt_descr *td, int offs)
179{
180 int res, ret = 0, i, j, act = 0;
181 struct nand_chip *this = mtd->priv;
182 size_t retlen, len, totlen;
183 loff_t from;
184 int bits = td->options & NAND_BBT_NRBITS_MSK;
185 uint8_t msk = (uint8_t)((1 << bits) - 1);
186 u32 marker_len;
187 int reserved_block_code = td->reserved_block_code;
188
189 totlen = (num * bits) >> 3;
190 marker_len = add_marker_len(td);
191 from = ((loff_t)page) << this->page_shift;
192
193 while (totlen) {
194 len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
195 if (marker_len) {
196 /*
197 * In case the BBT marker is not in the OOB area it
198 * will be just in the first page.
199 */
200 len -= marker_len;
201 from += marker_len;
202 marker_len = 0;
203 }
204 res = mtd_read(mtd, from, len, &retlen, buf);
205 if (res < 0) {
206 if (mtd_is_eccerr(res)) {
207 pr_info("nand_bbt: ECC error in BBT at "
208 "0x%012llx\n", from & ~mtd->writesize);
209 return res;
210 } else if (mtd_is_bitflip(res)) {
211 pr_info("nand_bbt: corrected error in BBT at "
212 "0x%012llx\n", from & ~mtd->writesize);
213 ret = res;
214 } else {
215 pr_info("nand_bbt: error reading BBT\n");
216 return res;
217 }
218 }
219
220 /* Analyse data */
221 for (i = 0; i < len; i++) {
222 uint8_t dat = buf[i];
223 for (j = 0; j < 8; j += bits, act += 2) {
224 uint8_t tmp = (dat >> j) & msk;
225 if (tmp == msk)
226 continue;
227 if (reserved_block_code && (tmp == reserved_block_code)) {
228 pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
229 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
230 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
231 mtd->ecc_stats.bbtblocks++;
232 continue;
233 }
234 /*
235 * Leave it for now, if it's matured we can
236 * move this message to pr_debug.
237 */
238 pr_info("nand_read_bbt: bad block at 0x%012llx\n",
239 (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
240 /* Factory marked bad or worn out? */
241 if (tmp == 0)
242 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
243 else
244 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
245 mtd->ecc_stats.badblocks++;
246 }
247 }
248 totlen -= len;
249 from += len;
250 }
251 return ret;
252}
253
254/**
255 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
256 * @mtd: MTD device structure
257 * @buf: temporary buffer
258 * @td: descriptor for the bad block table
259 * @chip: read the table for a specific chip, -1 read all chips; applies only if
260 * NAND_BBT_PERCHIP option is set
261 *
262 * Read the bad block table for all chips starting at a given page. We assume
263 * that the bbt bits are in consecutive order.
264 */
265static int read_abs_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
266{
267 struct nand_chip *this = mtd->priv;
268 int res = 0, i;
269
270 if (td->options & NAND_BBT_PERCHIP) {
271 int offs = 0;
272 for (i = 0; i < this->numchips; i++) {
273 if (chip == -1 || chip == i)
274 res = read_bbt(mtd, buf, td->pages[i],
275 this->chipsize >> this->bbt_erase_shift,
276 td, offs);
277 if (res)
278 return res;
279 offs += this->chipsize >> (this->bbt_erase_shift + 2);
280 }
281 } else {
282 res = read_bbt(mtd, buf, td->pages[0],
283 mtd->size >> this->bbt_erase_shift, td, 0);
284 if (res)
285 return res;
286 }
287 return 0;
288}
289
290/* BBT marker is in the first page, no OOB */
291static int scan_read_raw_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
292 struct nand_bbt_descr *td)
293{
294 size_t retlen;
295 size_t len;
296
297 len = td->len;
298 if (td->options & NAND_BBT_VERSION)
299 len++;
300
301 return mtd_read(mtd, offs, len, &retlen, buf);
302}
303
304/* Scan read raw data from flash */
305static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
306 size_t len)
307{
308 struct mtd_oob_ops ops;
309 int res;
310
311 ops.mode = MTD_OPS_RAW;
312 ops.ooboffs = 0;
313 ops.ooblen = mtd->oobsize;
314
315 while (len > 0) {
316 ops.datbuf = buf;
317 ops.len = min(len, (size_t)mtd->writesize);
318 ops.oobbuf = buf + ops.len;
319
320 res = mtd_read_oob(mtd, offs, &ops);
321
322 if (res)
323 return res;
324
325 buf += mtd->oobsize + mtd->writesize;
326 len -= mtd->writesize;
327 offs += mtd->writesize;
328 }
329 return 0;
330}
331
332static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
333 size_t len, struct nand_bbt_descr *td)
334{
335 if (td->options & NAND_BBT_NO_OOB)
336 return scan_read_raw_data(mtd, buf, offs, td);
337 else
338 return scan_read_raw_oob(mtd, buf, offs, len);
339}
340
341/* Scan write data with oob to flash */
342static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,
343 uint8_t *buf, uint8_t *oob)
344{
345 struct mtd_oob_ops ops;
346
347 ops.mode = MTD_OPS_PLACE_OOB;
348 ops.ooboffs = 0;
349 ops.ooblen = mtd->oobsize;
350 ops.datbuf = buf;
351 ops.oobbuf = oob;
352 ops.len = len;
353
354 return mtd_write_oob(mtd, offs, &ops);
355}
356
357static u32 bbt_get_ver_offs(struct mtd_info *mtd, struct nand_bbt_descr *td)
358{
359 u32 ver_offs = td->veroffs;
360
361 if (!(td->options & NAND_BBT_NO_OOB))
362 ver_offs += mtd->writesize;
363 return ver_offs;
364}
365
366/**
367 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
368 * @mtd: MTD device structure
369 * @buf: temporary buffer
370 * @td: descriptor for the bad block table
371 * @md: descriptor for the bad block table mirror
372 *
373 * Read the bad block table(s) for all chips starting at a given page. We
374 * assume that the bbt bits are in consecutive order.
375 */
376static int read_abs_bbts(struct mtd_info *mtd, uint8_t *buf,
377 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
378{
379 struct nand_chip *this = mtd->priv;
380
381 /* Read the primary version, if available */
382 if (td->options & NAND_BBT_VERSION) {
383 scan_read_raw(mtd, buf, (loff_t)td->pages[0] << this->page_shift,
384 mtd->writesize, td);
385 td->version[0] = buf[bbt_get_ver_offs(mtd, td)];
386 pr_info("Bad block table at page %d, version 0x%02X\n",
387 td->pages[0], td->version[0]);
388 }
389
390 /* Read the mirror version, if available */
391 if (md && (md->options & NAND_BBT_VERSION)) {
392 scan_read_raw(mtd, buf, (loff_t)md->pages[0] << this->page_shift,
393 mtd->writesize, td);
394 md->version[0] = buf[bbt_get_ver_offs(mtd, md)];
395 pr_info("Bad block table at page %d, version 0x%02X\n",
396 md->pages[0], md->version[0]);
397 }
398 return 1;
399}
400
401/* Scan a given block full */
402static int scan_block_full(struct mtd_info *mtd, struct nand_bbt_descr *bd,
403 loff_t offs, uint8_t *buf, size_t readlen,
404 int scanlen, int len)
405{
406 int ret, j;
407
408 ret = scan_read_raw_oob(mtd, buf, offs, readlen);
409 /* Ignore ECC errors when checking for BBM */
410 if (ret && !mtd_is_bitflip_or_eccerr(ret))
411 return ret;
412
413 for (j = 0; j < len; j++, buf += scanlen) {
414 if (check_pattern(buf, scanlen, mtd->writesize, bd))
415 return 1;
416 }
417 return 0;
418}
419
420/* Scan a given block partially */
421static int scan_block_fast(struct mtd_info *mtd, struct nand_bbt_descr *bd,
422 loff_t offs, uint8_t *buf, int len)
423{
424 struct mtd_oob_ops ops;
425 int j, ret;
426
427 ops.ooblen = mtd->oobsize;
428 ops.oobbuf = buf;
429 ops.ooboffs = 0;
430 ops.datbuf = NULL;
431 ops.mode = MTD_OPS_PLACE_OOB;
432
433 for (j = 0; j < len; j++) {
434 /*
435 * Read the full oob until read_oob is fixed to handle single
436 * byte reads for 16 bit buswidth.
437 */
438 ret = mtd_read_oob(mtd, offs, &ops);
439 /* Ignore ECC errors when checking for BBM */
440 if (ret && !mtd_is_bitflip_or_eccerr(ret))
441 return ret;
442
443 if (check_short_pattern(buf, bd))
444 return 1;
445
446 offs += mtd->writesize;
447 }
448 return 0;
449}
450
451/**
452 * create_bbt - [GENERIC] Create a bad block table by scanning the device
453 * @mtd: MTD device structure
454 * @buf: temporary buffer
455 * @bd: descriptor for the good/bad block search pattern
456 * @chip: create the table for a specific chip, -1 read all chips; applies only
457 * if NAND_BBT_PERCHIP option is set
458 *
459 * Create a bad block table by scanning the device for the given good/bad block
460 * identify pattern.
461 */
462static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
463 struct nand_bbt_descr *bd, int chip)
464{
465 struct nand_chip *this = mtd->priv;
466 int i, numblocks, len, scanlen;
467 int startblock;
468 loff_t from;
469 size_t readlen;
470
471 pr_info("Scanning device for bad blocks\n");
472
473 if (bd->options & NAND_BBT_SCANALLPAGES)
474 len = 1 << (this->bbt_erase_shift - this->page_shift);
475 else if (bd->options & NAND_BBT_SCAN2NDPAGE)
476 len = 2;
477 else
478 len = 1;
479
480 if (!(bd->options & NAND_BBT_SCANEMPTY)) {
481 /* We need only read few bytes from the OOB area */
482 scanlen = 0;
483 readlen = bd->len;
484 } else {
485 /* Full page content should be read */
486 scanlen = mtd->writesize + mtd->oobsize;
487 readlen = len * mtd->writesize;
488 }
489
490 if (chip == -1) {
491 /*
492 * Note that numblocks is 2 * (real numblocks) here, see i+=2
493 * below as it makes shifting and masking less painful
494 */
495 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
496 startblock = 0;
497 from = 0;
498 } else {
499 if (chip >= this->numchips) {
500 pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
501 chip + 1, this->numchips);
502 return -EINVAL;
503 }
504 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
505 startblock = chip * numblocks;
506 numblocks += startblock;
507 from = (loff_t)startblock << (this->bbt_erase_shift - 1);
508 }
509
510 if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
511 from += mtd->erasesize - (mtd->writesize * len);
512
513 for (i = startblock; i < numblocks;) {
514 int ret;
515
516 BUG_ON(bd->options & NAND_BBT_NO_OOB);
517
518 if (bd->options & NAND_BBT_SCANALLPAGES)
519 ret = scan_block_full(mtd, bd, from, buf, readlen,
520 scanlen, len);
521 else
522 ret = scan_block_fast(mtd, bd, from, buf, len);
523
524 if (ret < 0)
525 return ret;
526
527 if (ret) {
528 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
529 pr_warn("Bad eraseblock %d at 0x%012llx\n",
530 i >> 1, (unsigned long long)from);
531 mtd->ecc_stats.badblocks++;
532 }
533
534 i += 2;
535 from += (1 << this->bbt_erase_shift);
536 }
537 return 0;
538}
539
540/**
541 * search_bbt - [GENERIC] scan the device for a specific bad block table
542 * @mtd: MTD device structure
543 * @buf: temporary buffer
544 * @td: descriptor for the bad block table
545 *
546 * Read the bad block table by searching for a given ident pattern. Search is
547 * preformed either from the beginning up or from the end of the device
548 * downwards. The search starts always at the start of a block. If the option
549 * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
550 * the bad block information of this chip. This is necessary to provide support
551 * for certain DOC devices.
552 *
553 * The bbt ident pattern resides in the oob area of the first page in a block.
554 */
555static int search_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
556{
557 struct nand_chip *this = mtd->priv;
558 int i, chips;
559 int bits, startblock, block, dir;
560 int scanlen = mtd->writesize + mtd->oobsize;
561 int bbtblocks;
562 int blocktopage = this->bbt_erase_shift - this->page_shift;
563
564 /* Search direction top -> down? */
565 if (td->options & NAND_BBT_LASTBLOCK) {
566 startblock = (mtd->size >> this->bbt_erase_shift) - 1;
567 dir = -1;
568 } else {
569 startblock = 0;
570 dir = 1;
571 }
572
573 /* Do we have a bbt per chip? */
574 if (td->options & NAND_BBT_PERCHIP) {
575 chips = this->numchips;
576 bbtblocks = this->chipsize >> this->bbt_erase_shift;
577 startblock &= bbtblocks - 1;
578 } else {
579 chips = 1;
580 bbtblocks = mtd->size >> this->bbt_erase_shift;
581 }
582
583 /* Number of bits for each erase block in the bbt */
584 bits = td->options & NAND_BBT_NRBITS_MSK;
585
586 for (i = 0; i < chips; i++) {
587 /* Reset version information */
588 td->version[i] = 0;
589 td->pages[i] = -1;
590 /* Scan the maximum number of blocks */
591 for (block = 0; block < td->maxblocks; block++) {
592
593 int actblock = startblock + dir * block;
594 loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
595
596 /* Read first page */
597 scan_read_raw(mtd, buf, offs, mtd->writesize, td);
598 if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
599 td->pages[i] = actblock << blocktopage;
600 if (td->options & NAND_BBT_VERSION) {
601 offs = bbt_get_ver_offs(mtd, td);
602 td->version[i] = buf[offs];
603 }
604 break;
605 }
606 }
607 startblock += this->chipsize >> this->bbt_erase_shift;
608 }
609 /* Check, if we found a bbt for each requested chip */
610 for (i = 0; i < chips; i++) {
611 if (td->pages[i] == -1)
612 pr_warn("Bad block table not found for chip %d\n", i);
613 else
614 pr_info("Bad block table found at page %d, version "
615 "0x%02X\n", td->pages[i], td->version[i]);
616 }
617 return 0;
618}
619
620/**
621 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
622 * @mtd: MTD device structure
623 * @buf: temporary buffer
624 * @td: descriptor for the bad block table
625 * @md: descriptor for the bad block table mirror
626 *
627 * Search and read the bad block table(s).
628 */
629static int search_read_bbts(struct mtd_info *mtd, uint8_t * buf, struct nand_bbt_descr *td, struct nand_bbt_descr *md)
630{
631 /* Search the primary table */
632 search_bbt(mtd, buf, td);
633
634 /* Search the mirror table */
635 if (md)
636 search_bbt(mtd, buf, md);
637
638 /* Force result check */
639 return 1;
640}
641
642/**
643 * write_bbt - [GENERIC] (Re)write the bad block table
644 * @mtd: MTD device structure
645 * @buf: temporary buffer
646 * @td: descriptor for the bad block table
647 * @md: descriptor for the bad block table mirror
648 * @chipsel: selector for a specific chip, -1 for all
649 *
650 * (Re)write the bad block table.
651 */
652static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
653 struct nand_bbt_descr *td, struct nand_bbt_descr *md,
654 int chipsel)
655{
656 struct nand_chip *this = mtd->priv;
657 struct erase_info einfo;
658 int i, j, res, chip = 0;
659 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
660 int nrchips, bbtoffs, pageoffs, ooboffs;
661 uint8_t msk[4];
662 uint8_t rcode = td->reserved_block_code;
663 size_t retlen, len = 0;
664 loff_t to;
665 struct mtd_oob_ops ops;
666
667 ops.ooblen = mtd->oobsize;
668 ops.ooboffs = 0;
669 ops.datbuf = NULL;
670 ops.mode = MTD_OPS_PLACE_OOB;
671
672 if (!rcode)
673 rcode = 0xff;
674 /* Write bad block table per chip rather than per device? */
675 if (td->options & NAND_BBT_PERCHIP) {
676 numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
677 /* Full device write or specific chip? */
678 if (chipsel == -1) {
679 nrchips = this->numchips;
680 } else {
681 nrchips = chipsel + 1;
682 chip = chipsel;
683 }
684 } else {
685 numblocks = (int)(mtd->size >> this->bbt_erase_shift);
686 nrchips = 1;
687 }
688
689 /* Loop through the chips */
690 for (; chip < nrchips; chip++) {
691 /*
692 * There was already a version of the table, reuse the page
693 * This applies for absolute placement too, as we have the
694 * page nr. in td->pages.
695 */
696 if (td->pages[chip] != -1) {
697 page = td->pages[chip];
698 goto write;
699 }
700
701 /*
702 * Automatic placement of the bad block table. Search direction
703 * top -> down?
704 */
705 if (td->options & NAND_BBT_LASTBLOCK) {
706 startblock = numblocks * (chip + 1) - 1;
707 dir = -1;
708 } else {
709 startblock = chip * numblocks;
710 dir = 1;
711 }
712
713 for (i = 0; i < td->maxblocks; i++) {
714 int block = startblock + dir * i;
715 /* Check, if the block is bad */
716 switch ((this->bbt[block >> 2] >>
717 (2 * (block & 0x03))) & 0x03) {
718 case 0x01:
719 case 0x03:
720 continue;
721 }
722 page = block <<
723 (this->bbt_erase_shift - this->page_shift);
724 /* Check, if the block is used by the mirror table */
725 if (!md || md->pages[chip] != page)
726 goto write;
727 }
728 pr_err("No space left to write bad block table\n");
729 return -ENOSPC;
730 write:
731
732 /* Set up shift count and masks for the flash table */
733 bits = td->options & NAND_BBT_NRBITS_MSK;
734 msk[2] = ~rcode;
735 switch (bits) {
736 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
737 msk[3] = 0x01;
738 break;
739 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
740 msk[3] = 0x03;
741 break;
742 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
743 msk[3] = 0x0f;
744 break;
745 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
746 msk[3] = 0xff;
747 break;
748 default: return -EINVAL;
749 }
750
751 bbtoffs = chip * (numblocks >> 2);
752
753 to = ((loff_t)page) << this->page_shift;
754
755 /* Must we save the block contents? */
756 if (td->options & NAND_BBT_SAVECONTENT) {
757 /* Make it block aligned */
758 to &= ~((loff_t)((1 << this->bbt_erase_shift) - 1));
759 len = 1 << this->bbt_erase_shift;
760 res = mtd_read(mtd, to, len, &retlen, buf);
761 if (res < 0) {
762 if (retlen != len) {
763 pr_info("nand_bbt: error reading block "
764 "for writing the bad block table\n");
765 return res;
766 }
767 pr_warn("nand_bbt: ECC error while reading "
768 "block for writing bad block table\n");
769 }
770 /* Read oob data */
771 ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
772 ops.oobbuf = &buf[len];
773 res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
774 if (res < 0 || ops.oobretlen != ops.ooblen)
775 goto outerr;
776
777 /* Calc the byte offset in the buffer */
778 pageoffs = page - (int)(to >> this->page_shift);
779 offs = pageoffs << this->page_shift;
780 /* Preset the bbt area with 0xff */
781 memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
782 ooboffs = len + (pageoffs * mtd->oobsize);
783
784 } else if (td->options & NAND_BBT_NO_OOB) {
785 ooboffs = 0;
786 offs = td->len;
787 /* The version byte */
788 if (td->options & NAND_BBT_VERSION)
789 offs++;
790 /* Calc length */
791 len = (size_t)(numblocks >> sft);
792 len += offs;
793 /* Make it page aligned! */
794 len = ALIGN(len, mtd->writesize);
795 /* Preset the buffer with 0xff */
796 memset(buf, 0xff, len);
797 /* Pattern is located at the begin of first page */
798 memcpy(buf, td->pattern, td->len);
799 } else {
800 /* Calc length */
801 len = (size_t)(numblocks >> sft);
802 /* Make it page aligned! */
803 len = ALIGN(len, mtd->writesize);
804 /* Preset the buffer with 0xff */
805 memset(buf, 0xff, len +
806 (len >> this->page_shift)* mtd->oobsize);
807 offs = 0;
808 ooboffs = len;
809 /* Pattern is located in oob area of first page */
810 memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
811 }
812
813 if (td->options & NAND_BBT_VERSION)
814 buf[ooboffs + td->veroffs] = td->version[chip];
815
816 /* Walk through the memory table */
817 for (i = 0; i < numblocks;) {
818 uint8_t dat;
819 dat = this->bbt[bbtoffs + (i >> 2)];
820 for (j = 0; j < 4; j++, i++) {
821 int sftcnt = (i << (3 - sft)) & sftmsk;
822 /* Do not store the reserved bbt blocks! */
823 buf[offs + (i >> sft)] &=
824 ~(msk[dat & 0x03] << sftcnt);
825 dat >>= 2;
826 }
827 }
828
829 memset(&einfo, 0, sizeof(einfo));
830 einfo.mtd = mtd;
831 einfo.addr = to;
832 einfo.len = 1 << this->bbt_erase_shift;
833 res = nand_erase_nand(mtd, &einfo, 1);
834 if (res < 0)
835 goto outerr;
836
837 res = scan_write_bbt(mtd, to, len, buf,
838 td->options & NAND_BBT_NO_OOB ? NULL :
839 &buf[len]);
840 if (res < 0)
841 goto outerr;
842
843 pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
844 (unsigned long long)to, td->version[chip]);
845
846 /* Mark it as used */
847 td->pages[chip] = page;
848 }
849 return 0;
850
851 outerr:
852 pr_warn("nand_bbt: error while writing bad block table %d\n", res);
853 return res;
854}
855
856/**
857 * nand_memory_bbt - [GENERIC] create a memory based bad block table
858 * @mtd: MTD device structure
859 * @bd: descriptor for the good/bad block search pattern
860 *
861 * The function creates a memory based bbt by scanning the device for
862 * manufacturer / software marked good / bad blocks.
863 */
864static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
865{
866 struct nand_chip *this = mtd->priv;
867
868 bd->options &= ~NAND_BBT_SCANEMPTY;
869 return create_bbt(mtd, this->buffers->databuf, bd, -1);
870}
871
872/**
873 * check_create - [GENERIC] create and write bbt(s) if necessary
874 * @mtd: MTD device structure
875 * @buf: temporary buffer
876 * @bd: descriptor for the good/bad block search pattern
877 *
878 * The function checks the results of the previous call to read_bbt and creates
879 * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
880 * for the chip/device. Update is necessary if one of the tables is missing or
881 * the version nr. of one table is less than the other.
882 */
883static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
884{
885 int i, chips, writeops, create, chipsel, res, res2;
886 struct nand_chip *this = mtd->priv;
887 struct nand_bbt_descr *td = this->bbt_td;
888 struct nand_bbt_descr *md = this->bbt_md;
889 struct nand_bbt_descr *rd, *rd2;
890
891 /* Do we have a bbt per chip? */
892 if (td->options & NAND_BBT_PERCHIP)
893 chips = this->numchips;
894 else
895 chips = 1;
896
897 for (i = 0; i < chips; i++) {
898 writeops = 0;
899 create = 0;
900 rd = NULL;
901 rd2 = NULL;
902 res = res2 = 0;
903 /* Per chip or per device? */
904 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
905 /* Mirrored table available? */
906 if (md) {
907 if (td->pages[i] == -1 && md->pages[i] == -1) {
908 create = 1;
909 writeops = 0x03;
910 } else if (td->pages[i] == -1) {
911 rd = md;
912 writeops = 0x01;
913 } else if (md->pages[i] == -1) {
914 rd = td;
915 writeops = 0x02;
916 } else if (td->version[i] == md->version[i]) {
917 rd = td;
918 if (!(td->options & NAND_BBT_VERSION))
919 rd2 = md;
920 } else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
921 rd = td;
922 writeops = 0x02;
923 } else {
924 rd = md;
925 writeops = 0x01;
926 }
927 } else {
928 if (td->pages[i] == -1) {
929 create = 1;
930 writeops = 0x01;
931 } else {
932 rd = td;
933 }
934 }
935
936 if (create) {
937 /* Create the bad block table by scanning the device? */
938 if (!(td->options & NAND_BBT_CREATE))
939 continue;
940
941 /* Create the table in memory by scanning the chip(s) */
942 if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
943 create_bbt(mtd, buf, bd, chipsel);
944
945 td->version[i] = 1;
946 if (md)
947 md->version[i] = 1;
948 }
949
950 /* Read back first? */
951 if (rd) {
952 res = read_abs_bbt(mtd, buf, rd, chipsel);
953 if (mtd_is_eccerr(res)) {
954 /* Mark table as invalid */
955 rd->pages[i] = -1;
956 rd->version[i] = 0;
957 i--;
958 continue;
959 }
960 }
961 /* If they weren't versioned, read both */
962 if (rd2) {
963 res2 = read_abs_bbt(mtd, buf, rd2, chipsel);
964 if (mtd_is_eccerr(res2)) {
965 /* Mark table as invalid */
966 rd2->pages[i] = -1;
967 rd2->version[i] = 0;
968 i--;
969 continue;
970 }
971 }
972
973 /* Scrub the flash table(s)? */
974 if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
975 writeops = 0x03;
976
977 /* Update version numbers before writing */
978 if (md) {
979 td->version[i] = max(td->version[i], md->version[i]);
980 md->version[i] = td->version[i];
981 }
982
983 /* Write the bad block table to the device? */
984 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
985 res = write_bbt(mtd, buf, td, md, chipsel);
986 if (res < 0)
987 return res;
988 }
989
990 /* Write the mirror bad block table to the device? */
991 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
992 res = write_bbt(mtd, buf, md, td, chipsel);
993 if (res < 0)
994 return res;
995 }
996 }
997 return 0;
998}
999
1000/**
1001 * mark_bbt_regions - [GENERIC] mark the bad block table regions
1002 * @mtd: MTD device structure
1003 * @td: bad block table descriptor
1004 *
1005 * The bad block table regions are marked as "bad" to prevent accidental
1006 * erasures / writes. The regions are identified by the mark 0x02.
1007 */
1008static void mark_bbt_region(struct mtd_info *mtd, struct nand_bbt_descr *td)
1009{
1010 struct nand_chip *this = mtd->priv;
1011 int i, j, chips, block, nrblocks, update;
1012 uint8_t oldval, newval;
1013
1014 /* Do we have a bbt per chip? */
1015 if (td->options & NAND_BBT_PERCHIP) {
1016 chips = this->numchips;
1017 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
1018 } else {
1019 chips = 1;
1020 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1021 }
1022
1023 for (i = 0; i < chips; i++) {
1024 if ((td->options & NAND_BBT_ABSPAGE) ||
1025 !(td->options & NAND_BBT_WRITE)) {
1026 if (td->pages[i] == -1)
1027 continue;
1028 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1029 block <<= 1;
1030 oldval = this->bbt[(block >> 3)];
1031 newval = oldval | (0x2 << (block & 0x06));
1032 this->bbt[(block >> 3)] = newval;
1033 if ((oldval != newval) && td->reserved_block_code)
1034 nand_update_bbt(mtd, (loff_t)block << (this->bbt_erase_shift - 1));
1035 continue;
1036 }
1037 update = 0;
1038 if (td->options & NAND_BBT_LASTBLOCK)
1039 block = ((i + 1) * nrblocks) - td->maxblocks;
1040 else
1041 block = i * nrblocks;
1042 block <<= 1;
1043 for (j = 0; j < td->maxblocks; j++) {
1044 oldval = this->bbt[(block >> 3)];
1045 newval = oldval | (0x2 << (block & 0x06));
1046 this->bbt[(block >> 3)] = newval;
1047 if (oldval != newval)
1048 update = 1;
1049 block += 2;
1050 }
1051 /*
1052 * If we want reserved blocks to be recorded to flash, and some
1053 * new ones have been marked, then we need to update the stored
1054 * bbts. This should only happen once.
1055 */
1056 if (update && td->reserved_block_code)
1057 nand_update_bbt(mtd, (loff_t)(block - 2) << (this->bbt_erase_shift - 1));
1058 }
1059}
1060
1061/**
1062 * verify_bbt_descr - verify the bad block description
1063 * @mtd: MTD device structure
1064 * @bd: the table to verify
1065 *
1066 * This functions performs a few sanity checks on the bad block description
1067 * table.
1068 */
1069static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1070{
1071 struct nand_chip *this = mtd->priv;
1072 u32 pattern_len;
1073 u32 bits;
1074 u32 table_size;
1075
1076 if (!bd)
1077 return;
1078
1079 pattern_len = bd->len;
1080 bits = bd->options & NAND_BBT_NRBITS_MSK;
1081
1082 BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1083 !(this->bbt_options & NAND_BBT_USE_FLASH));
1084 BUG_ON(!bits);
1085
1086 if (bd->options & NAND_BBT_VERSION)
1087 pattern_len++;
1088
1089 if (bd->options & NAND_BBT_NO_OOB) {
1090 BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1091 BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1092 BUG_ON(bd->offs);
1093 if (bd->options & NAND_BBT_VERSION)
1094 BUG_ON(bd->veroffs != bd->len);
1095 BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1096 }
1097
1098 if (bd->options & NAND_BBT_PERCHIP)
1099 table_size = this->chipsize >> this->bbt_erase_shift;
1100 else
1101 table_size = mtd->size >> this->bbt_erase_shift;
1102 table_size >>= 3;
1103 table_size *= bits;
1104 if (bd->options & NAND_BBT_NO_OOB)
1105 table_size += pattern_len;
1106 BUG_ON(table_size > (1 << this->bbt_erase_shift));
1107}
1108
1109/**
1110 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1111 * @mtd: MTD device structure
1112 * @bd: descriptor for the good/bad block search pattern
1113 *
1114 * The function checks, if a bad block table(s) is/are already available. If
1115 * not it scans the device for manufacturer marked good / bad blocks and writes
1116 * the bad block table(s) to the selected place.
1117 *
1118 * The bad block table memory is allocated here. It must be freed by calling
1119 * the nand_free_bbt function.
1120 */
1121int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
1122{
1123 struct nand_chip *this = mtd->priv;
1124 int len, res = 0;
1125 uint8_t *buf;
1126 struct nand_bbt_descr *td = this->bbt_td;
1127 struct nand_bbt_descr *md = this->bbt_md;
1128
1129 len = mtd->size >> (this->bbt_erase_shift + 2);
1130 /*
1131 * Allocate memory (2bit per block) and clear the memory bad block
1132 * table.
1133 */
1134 this->bbt = kzalloc(len, GFP_KERNEL);
1135 if (!this->bbt)
1136 return -ENOMEM;
1137
1138 /*
1139 * If no primary table decriptor is given, scan the device to build a
1140 * memory based bad block table.
1141 */
1142 if (!td) {
1143 if ((res = nand_memory_bbt(mtd, bd))) {
1144 pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1145 kfree(this->bbt);
1146 this->bbt = NULL;
1147 }
1148 return res;
1149 }
1150 verify_bbt_descr(mtd, td);
1151 verify_bbt_descr(mtd, md);
1152
1153 /* Allocate a temporary buffer for one eraseblock incl. oob */
1154 len = (1 << this->bbt_erase_shift);
1155 len += (len >> this->page_shift) * mtd->oobsize;
1156 buf = vmalloc(len);
1157 if (!buf) {
1158 kfree(this->bbt);
1159 this->bbt = NULL;
1160 return -ENOMEM;
1161 }
1162
1163 /* Is the bbt at a given page? */
1164 if (td->options & NAND_BBT_ABSPAGE) {
1165 res = read_abs_bbts(mtd, buf, td, md);
1166 } else {
1167 /* Search the bad block table using a pattern in oob */
1168 res = search_read_bbts(mtd, buf, td, md);
1169 }
1170
1171 if (res)
1172 res = check_create(mtd, buf, bd);
1173
1174 /* Prevent the bbt regions from erasing / writing */
1175 mark_bbt_region(mtd, td);
1176 if (md)
1177 mark_bbt_region(mtd, md);
1178
1179 vfree(buf);
1180 return res;
1181}
1182
1183/**
1184 * nand_update_bbt - [NAND Interface] update bad block table(s)
1185 * @mtd: MTD device structure
1186 * @offs: the offset of the newly marked block
1187 *
1188 * The function updates the bad block table(s).
1189 */
1190int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
1191{
1192 struct nand_chip *this = mtd->priv;
1193 int len, res = 0;
1194 int chip, chipsel;
1195 uint8_t *buf;
1196 struct nand_bbt_descr *td = this->bbt_td;
1197 struct nand_bbt_descr *md = this->bbt_md;
1198
1199 if (!this->bbt || !td)
1200 return -EINVAL;
1201
1202 /* Allocate a temporary buffer for one eraseblock incl. oob */
1203 len = (1 << this->bbt_erase_shift);
1204 len += (len >> this->page_shift) * mtd->oobsize;
1205 buf = kmalloc(len, GFP_KERNEL);
1206 if (!buf)
1207 return -ENOMEM;
1208
1209 /* Do we have a bbt per chip? */
1210 if (td->options & NAND_BBT_PERCHIP) {
1211 chip = (int)(offs >> this->chip_shift);
1212 chipsel = chip;
1213 } else {
1214 chip = 0;
1215 chipsel = -1;
1216 }
1217
1218 td->version[chip]++;
1219 if (md)
1220 md->version[chip]++;
1221
1222 /* Write the bad block table to the device? */
1223 if (td->options & NAND_BBT_WRITE) {
1224 res = write_bbt(mtd, buf, td, md, chipsel);
1225 if (res < 0)
1226 goto out;
1227 }
1228 /* Write the mirror bad block table to the device? */
1229 if (md && (md->options & NAND_BBT_WRITE)) {
1230 res = write_bbt(mtd, buf, md, td, chipsel);
1231 }
1232
1233 out:
1234 kfree(buf);
1235 return res;
1236}
1237
1238/*
1239 * Define some generic bad / good block scan pattern which are used
1240 * while scanning a device for factory marked good / bad blocks.
1241 */
1242static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1243
1244static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
1245
1246static struct nand_bbt_descr agand_flashbased = {
1247 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
1248 .offs = 0x20,
1249 .len = 6,
1250 .pattern = scan_agand_pattern
1251};
1252
1253/* Generic flash bbt descriptors */
1254static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1255static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1256
1257static struct nand_bbt_descr bbt_main_descr = {
1258 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1259 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1260 .offs = 8,
1261 .len = 4,
1262 .veroffs = 12,
1263 .maxblocks = 4,
1264 .pattern = bbt_pattern
1265};
1266
1267static struct nand_bbt_descr bbt_mirror_descr = {
1268 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1269 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1270 .offs = 8,
1271 .len = 4,
1272 .veroffs = 12,
1273 .maxblocks = 4,
1274 .pattern = mirror_pattern
1275};
1276
1277static struct nand_bbt_descr bbt_main_no_bbt_descr = {
1278 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1279 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1280 | NAND_BBT_NO_OOB,
1281 .len = 4,
1282 .veroffs = 4,
1283 .maxblocks = 4,
1284 .pattern = bbt_pattern
1285};
1286
1287static struct nand_bbt_descr bbt_mirror_no_bbt_descr = {
1288 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1289 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1290 | NAND_BBT_NO_OOB,
1291 .len = 4,
1292 .veroffs = 4,
1293 .maxblocks = 4,
1294 .pattern = mirror_pattern
1295};
1296
1297#define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1298/**
1299 * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1300 * @this: NAND chip to create descriptor for
1301 *
1302 * This function allocates and initializes a nand_bbt_descr for BBM detection
1303 * based on the properties of @this. The new descriptor is stored in
1304 * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1305 * passed to this function.
1306 */
1307static int nand_create_badblock_pattern(struct nand_chip *this)
1308{
1309 struct nand_bbt_descr *bd;
1310 if (this->badblock_pattern) {
1311 pr_warn("Bad block pattern already allocated; not replacing\n");
1312 return -EINVAL;
1313 }
1314 bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1315 if (!bd)
1316 return -ENOMEM;
1317 bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1318 bd->offs = this->badblockpos;
1319 bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1320 bd->pattern = scan_ff_pattern;
1321 bd->options |= NAND_BBT_DYNAMICSTRUCT;
1322 this->badblock_pattern = bd;
1323 return 0;
1324}
1325
1326/**
1327 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1328 * @mtd: MTD device structure
1329 *
1330 * This function selects the default bad block table support for the device and
1331 * calls the nand_scan_bbt function.
1332 */
1333int nand_default_bbt(struct mtd_info *mtd)
1334{
1335 struct nand_chip *this = mtd->priv;
1336
1337 /*
1338 * Default for AG-AND. We must use a flash based bad block table as the
1339 * devices have factory marked _good_ blocks. Erasing those blocks
1340 * leads to loss of the good / bad information, so we _must_ store this
1341 * information in a good / bad table during startup.
1342 */
1343 if (this->options & NAND_IS_AND) {
1344 /* Use the default pattern descriptors */
1345 if (!this->bbt_td) {
1346 this->bbt_td = &bbt_main_descr;
1347 this->bbt_md = &bbt_mirror_descr;
1348 }
1349 this->bbt_options |= NAND_BBT_USE_FLASH;
1350 return nand_scan_bbt(mtd, &agand_flashbased);
1351 }
1352
1353 /* Is a flash based bad block table requested? */
1354 if (this->bbt_options & NAND_BBT_USE_FLASH) {
1355 /* Use the default pattern descriptors */
1356 if (!this->bbt_td) {
1357 if (this->bbt_options & NAND_BBT_NO_OOB) {
1358 this->bbt_td = &bbt_main_no_bbt_descr;
1359 this->bbt_md = &bbt_mirror_no_bbt_descr;
1360 } else {
1361 this->bbt_td = &bbt_main_descr;
1362 this->bbt_md = &bbt_mirror_descr;
1363 }
1364 }
1365 } else {
1366 this->bbt_td = NULL;
1367 this->bbt_md = NULL;
1368 }
1369
1370 if (!this->badblock_pattern)
1371 nand_create_badblock_pattern(this);
1372
1373 return nand_scan_bbt(mtd, this->badblock_pattern);
1374}
1375
1376/**
1377 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1378 * @mtd: MTD device structure
1379 * @offs: offset in the device
1380 * @allowbbt: allow access to bad block table region
1381 */
1382int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
1383{
1384 struct nand_chip *this = mtd->priv;
1385 int block;
1386 uint8_t res;
1387
1388 /* Get block number * 2 */
1389 block = (int)(offs >> (this->bbt_erase_shift - 1));
1390 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1391
1392 pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: "
1393 "(block %d) 0x%02x\n",
1394 (unsigned int)offs, block >> 1, res);
1395
1396 switch ((int)res) {
1397 case 0x00:
1398 return 0;
1399 case 0x01:
1400 return 1;
1401 case 0x02:
1402 return allowbbt ? 0 : 1;
1403 }
1404 return 1;
1405}
1406
1407EXPORT_SYMBOL(nand_scan_bbt);
1408EXPORT_SYMBOL(nand_default_bbt);