initial commit with v2.6.9
[linux-2.6.9-moxart.git] / drivers / mtd / nand / nand_bbt.c
blob2642e11516e737be2491e9653adf4b819d7c318a
1 /*
2 * drivers/mtd/nand_bbt.c
4 * Overview:
5 * Bad block table support for the NAND driver
6 *
7 * Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
9 * $Id: nand_bbt.c,v 1.24 2004/06/28 08:25:35 gleixner Exp $
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
15 * Description:
17 * When nand_scan_bbt is called, then it tries to find the bad block table
18 * depending on the options in the bbt descriptor(s). If a bbt is found
19 * then the contents are read and the memory based bbt is created. If a
20 * mirrored bbt is selected then the mirror is searched too and the
21 * versions are compared. If the mirror has a greater version number
22 * than the mirror bbt is used to build the memory based bbt.
23 * If the tables are not versioned, then we "or" the bad block information.
24 * If one of the bbt's is out of date or does not exist it is (re)created.
25 * If no bbt exists at all then the device is scanned for factory marked
26 * good / bad blocks and the bad block tables are created.
28 * For manufacturer created bbts like the one found on M-SYS DOC devices
29 * the bbt is searched and read but never created
31 * The autogenerated bad block table is located in the last good blocks
32 * of the device. The table is mirrored, so it can be updated eventually.
33 * The table is marked in the oob area with an ident pattern and a version
34 * number which indicates which of both tables is more up to date.
36 * The table uses 2 bits per block
37 * 11b: block is good
38 * 00b: block is factory marked bad
39 * 01b, 10b: block is marked bad due to wear
41 * The memory bad block table uses the following scheme:
42 * 00b: block is good
43 * 01b: block is marked bad due to wear
44 * 10b: block is reserved (to protect the bbt area)
45 * 11b: block is factory marked bad
47 * Multichip devices like DOC store the bad block info per floor.
49 * Following assumptions are made:
50 * - bbts start at a page boundary, if autolocated on a block boundary
51 * - the space neccecary for a bbt in FLASH does not exceed a block boundary
55 #include <linux/slab.h>
56 #include <linux/types.h>
57 #include <linux/mtd/mtd.h>
58 #include <linux/mtd/nand.h>
59 #include <linux/mtd/nand_ecc.h>
60 #include <linux/mtd/compatmac.h>
61 #include <linux/bitops.h>
62 #include <linux/delay.h>
65 /**
66 * check_pattern - [GENERIC] check if a pattern is in the buffer
67 * @buf: the buffer to search
68 * @len: the length of buffer to search
69 * @paglen: the pagelength
70 * @td: search pattern descriptor
72 * Check for a pattern at the given place. Used to search bad block
73 * tables and good / bad block identifiers.
74 * If the SCAN_EMPTY option is set then check, if all bytes except the
75 * pattern area contain 0xff
78 static int check_pattern (uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
80 int i, end;
81 uint8_t *p = buf;
83 end = paglen + td->offs;
84 if (td->options & NAND_BBT_SCANEMPTY) {
85 for (i = 0; i < end; i++) {
86 if (p[i] != 0xff)
87 return -1;
90 p += end;
92 /* Compare the pattern */
93 for (i = 0; i < td->len; i++) {
94 if (p[i] != td->pattern[i])
95 return -1;
98 p += td->len;
99 end += td->len;
100 if (td->options & NAND_BBT_SCANEMPTY) {
101 for (i = end; i < len; i++) {
102 if (*p++ != 0xff)
103 return -1;
106 return 0;
110 * read_bbt - [GENERIC] Read the bad block table starting from page
111 * @mtd: MTD device structure
112 * @buf: temporary buffer
113 * @page: the starting page
114 * @num: the number of bbt descriptors to read
115 * @bits: number of bits per block
116 * @offs: offset in the memory table
118 * Read the bad block table starting from page.
121 static int read_bbt (struct mtd_info *mtd, uint8_t *buf, int page, int num,
122 int bits, int offs, int reserved_block_code)
124 int res, i, j, act = 0;
125 struct nand_chip *this = mtd->priv;
126 size_t retlen, len, totlen;
127 loff_t from;
128 uint8_t msk = (uint8_t) ((1 << bits) - 1);
130 totlen = (num * bits) >> 3;
131 from = ((loff_t)page) << this->page_shift;
133 while (totlen) {
134 len = min (totlen, (size_t) (1 << this->bbt_erase_shift));
135 res = mtd->read_ecc (mtd, from, len, &retlen, buf, NULL, this->autooob);
136 if (res < 0) {
137 if (retlen != len) {
138 printk (KERN_INFO "nand_bbt: Error reading bad block table\n");
139 return res;
141 printk (KERN_WARNING "nand_bbt: ECC error while reading bad block table\n");
144 /* Analyse data */
145 for (i = 0; i < len; i++) {
146 uint8_t dat = buf[i];
147 for (j = 0; j < 8; j += bits, act += 2) {
148 uint8_t tmp = (dat >> j) & msk;
149 if (tmp == msk)
150 continue;
151 if (reserved_block_code &&
152 (tmp == reserved_block_code)) {
153 printk (KERN_DEBUG "nand_read_bbt: Reserved block at 0x%08x\n",
154 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
155 this->bbt[offs + (act >> 3)] |= 0x2 << (act & 0x06);
156 continue;
158 /* Leave it for now, if its matured we can move this
159 * message to MTD_DEBUG_LEVEL0 */
160 printk (KERN_DEBUG "nand_read_bbt: Bad block at 0x%08x\n",
161 ((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
162 /* Factory marked bad or worn out ? */
163 if (tmp == 0)
164 this->bbt[offs + (act >> 3)] |= 0x3 << (act & 0x06);
165 else
166 this->bbt[offs + (act >> 3)] |= 0x1 << (act & 0x06);
169 totlen -= len;
170 from += len;
172 return 0;
176 * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
177 * @mtd: MTD device structure
178 * @buf: temporary buffer
179 * @td: descriptor for the bad block table
180 * @chip: read the table for a specific chip, -1 read all chips.
181 * Applies only if NAND_BBT_PERCHIP option is set
183 * Read the bad block table for all chips starting at a given page
184 * We assume that the bbt bits are in consecutive order.
186 static int read_abs_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td, int chip)
188 struct nand_chip *this = mtd->priv;
189 int res = 0, i;
190 int bits;
192 bits = td->options & NAND_BBT_NRBITS_MSK;
193 if (td->options & NAND_BBT_PERCHIP) {
194 int offs = 0;
195 for (i = 0; i < this->numchips; i++) {
196 if (chip == -1 || chip == i)
197 res = read_bbt (mtd, buf, td->pages[i], this->chipsize >> this->bbt_erase_shift, bits, offs, td->reserved_block_code);
198 if (res)
199 return res;
200 offs += this->chipsize >> (this->bbt_erase_shift + 2);
202 } else {
203 res = read_bbt (mtd, buf, td->pages[0], mtd->size >> this->bbt_erase_shift, bits, 0, td->reserved_block_code);
204 if (res)
205 return res;
207 return 0;
211 * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
212 * @mtd: MTD device structure
213 * @buf: temporary buffer
214 * @td: descriptor for the bad block table
215 * @md: descriptor for the bad block table mirror
217 * Read the bad block table(s) for all chips starting at a given page
218 * We assume that the bbt bits are in consecutive order.
221 static int read_abs_bbts (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td,
222 struct nand_bbt_descr *md)
224 struct nand_chip *this = mtd->priv;
226 /* Read the primary version, if available */
227 if (td->options & NAND_BBT_VERSION) {
228 nand_read_raw (mtd, buf, td->pages[0] << this->page_shift, mtd->oobblock, mtd->oobsize);
229 td->version[0] = buf[mtd->oobblock + td->veroffs];
230 printk (KERN_DEBUG "Bad block table at page %d, version 0x%02X\n", td->pages[0], td->version[0]);
233 /* Read the mirror version, if available */
234 if (md && (md->options & NAND_BBT_VERSION)) {
235 nand_read_raw (mtd, buf, md->pages[0] << this->page_shift, mtd->oobblock, mtd->oobsize);
236 md->version[0] = buf[mtd->oobblock + md->veroffs];
237 printk (KERN_DEBUG "Bad block table at page %d, version 0x%02X\n", md->pages[0], md->version[0]);
240 return 1;
244 * create_bbt - [GENERIC] Create a bad block table by scanning the device
245 * @mtd: MTD device structure
246 * @buf: temporary buffer
247 * @bd: descriptor for the good/bad block search pattern
248 * @chip: create the table for a specific chip, -1 read all chips.
249 * Applies only if NAND_BBT_PERCHIP option is set
251 * Create a bad block table by scanning the device
252 * for the given good/bad block identify pattern
254 static void create_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
256 struct nand_chip *this = mtd->priv;
257 int i, j, numblocks, len, scanlen;
258 int startblock;
259 loff_t from;
260 size_t readlen, ooblen;
262 printk (KERN_INFO "Scanning device for bad blocks\n");
264 if (bd->options & NAND_BBT_SCANALLPAGES)
265 len = 1 << (this->bbt_erase_shift - this->page_shift);
266 else {
267 if (bd->options & NAND_BBT_SCAN2NDPAGE)
268 len = 2;
269 else
270 len = 1;
272 scanlen = mtd->oobblock + mtd->oobsize;
273 readlen = len * mtd->oobblock;
274 ooblen = len * mtd->oobsize;
276 if (chip == -1) {
277 /* Note that numblocks is 2 * (real numblocks) here, see i+=2 below as it
278 * makes shifting and masking less painful */
279 numblocks = mtd->size >> (this->bbt_erase_shift - 1);
280 startblock = 0;
281 from = 0;
282 } else {
283 if (chip >= this->numchips) {
284 printk (KERN_WARNING "create_bbt(): chipnr (%d) > available chips (%d)\n",
285 chip + 1, this->numchips);
286 return;
288 numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
289 startblock = chip * numblocks;
290 numblocks += startblock;
291 from = startblock << (this->bbt_erase_shift - 1);
294 for (i = startblock; i < numblocks;) {
295 nand_read_raw (mtd, buf, from, readlen, ooblen);
296 for (j = 0; j < len; j++) {
297 if (check_pattern (&buf[j * scanlen], scanlen, mtd->oobblock, bd)) {
298 this->bbt[i >> 3] |= 0x03 << (i & 0x6);
299 printk (KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
300 i >> 1, (unsigned int) from);
301 break;
304 i += 2;
305 from += (1 << this->bbt_erase_shift);
310 * search_bbt - [GENERIC] scan the device for a specific bad block table
311 * @mtd: MTD device structure
312 * @buf: temporary buffer
313 * @td: descriptor for the bad block table
315 * Read the bad block table by searching for a given ident pattern.
316 * Search is preformed either from the beginning up or from the end of
317 * the device downwards. The search starts always at the start of a
318 * block.
319 * If the option NAND_BBT_PERCHIP is given, each chip is searched
320 * for a bbt, which contains the bad block information of this chip.
321 * This is neccecary to provide support for certain DOC devices.
323 * The bbt ident pattern resides in the oob area of the first page
324 * in a block.
326 static int search_bbt (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *td)
328 struct nand_chip *this = mtd->priv;
329 int i, chips;
330 int bits, startblock, block, dir;
331 int scanlen = mtd->oobblock + mtd->oobsize;
332 int bbtblocks;
334 /* Search direction top -> down ? */
335 if (td->options & NAND_BBT_LASTBLOCK) {
336 startblock = (mtd->size >> this->bbt_erase_shift) -1;
337 dir = -1;
338 } else {
339 startblock = 0;
340 dir = 1;
343 /* Do we have a bbt per chip ? */
344 if (td->options & NAND_BBT_PERCHIP) {
345 chips = this->numchips;
346 bbtblocks = this->chipsize >> this->bbt_erase_shift;
347 startblock &= bbtblocks - 1;
348 } else {
349 chips = 1;
350 bbtblocks = mtd->size >> this->bbt_erase_shift;
353 /* Number of bits for each erase block in the bbt */
354 bits = td->options & NAND_BBT_NRBITS_MSK;
356 for (i = 0; i < chips; i++) {
357 /* Reset version information */
358 td->version[i] = 0;
359 td->pages[i] = -1;
360 /* Scan the maximum number of blocks */
361 for (block = 0; block < td->maxblocks; block++) {
362 int actblock = startblock + dir * block;
363 /* Read first page */
364 nand_read_raw (mtd, buf, actblock << this->bbt_erase_shift, mtd->oobblock, mtd->oobsize);
365 if (!check_pattern(buf, scanlen, mtd->oobblock, td)) {
366 td->pages[i] = actblock << (this->bbt_erase_shift - this->page_shift);
367 if (td->options & NAND_BBT_VERSION) {
368 td->version[i] = buf[mtd->oobblock + td->veroffs];
370 break;
373 startblock += this->chipsize >> this->bbt_erase_shift;
375 /* Check, if we found a bbt for each requested chip */
376 for (i = 0; i < chips; i++) {
377 if (td->pages[i] == -1)
378 printk (KERN_WARNING "Bad block table not found for chip %d\n", i);
379 else
380 printk (KERN_DEBUG "Bad block table found at page %d, version 0x%02X\n", td->pages[i], td->version[i]);
382 return 0;
386 * search_read_bbts - [GENERIC] scan the device for bad block table(s)
387 * @mtd: MTD device structure
388 * @buf: temporary buffer
389 * @td: descriptor for the bad block table
390 * @md: descriptor for the bad block table mirror
392 * Search and read the bad block table(s)
394 static int search_read_bbts (struct mtd_info *mtd, uint8_t *buf,
395 struct nand_bbt_descr *td, struct nand_bbt_descr *md)
397 /* Search the primary table */
398 search_bbt (mtd, buf, td);
400 /* Search the mirror table */
401 if (md)
402 search_bbt (mtd, buf, md);
404 /* Force result check */
405 return 1;
409 /**
410 * write_bbt - [GENERIC] (Re)write the bad block table
412 * @mtd: MTD device structure
413 * @buf: temporary buffer
414 * @td: descriptor for the bad block table
415 * @md: descriptor for the bad block table mirror
416 * @chipsel: selector for a specific chip, -1 for all
418 * (Re)write the bad block table
421 static int write_bbt (struct mtd_info *mtd, uint8_t *buf,
422 struct nand_bbt_descr *td, struct nand_bbt_descr *md, int chipsel)
424 struct nand_chip *this = mtd->priv;
425 struct nand_oobinfo oobinfo;
426 struct erase_info einfo;
427 int i, j, res, chip = 0;
428 int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
429 int nrchips, bbtoffs, pageoffs;
430 uint8_t msk[4];
431 uint8_t rcode = td->reserved_block_code;
432 size_t retlen, len = 0;
433 loff_t to;
435 if (!rcode)
436 rcode = 0xff;
437 /* Write bad block table per chip rather than per device ? */
438 if (td->options & NAND_BBT_PERCHIP) {
439 numblocks = (int) (this->chipsize >> this->bbt_erase_shift);
440 /* Full device write or specific chip ? */
441 if (chipsel == -1) {
442 nrchips = this->numchips;
443 } else {
444 nrchips = chipsel + 1;
445 chip = chipsel;
447 } else {
448 numblocks = (int) (mtd->size >> this->bbt_erase_shift);
449 nrchips = 1;
452 /* Loop through the chips */
453 for (; chip < nrchips; chip++) {
455 /* There was already a version of the table, reuse the page
456 * This applies for absolute placement too, as we have the
457 * page nr. in td->pages.
459 if (td->pages[chip] != -1) {
460 page = td->pages[chip];
461 goto write;
464 /* Automatic placement of the bad block table */
465 /* Search direction top -> down ? */
466 if (td->options & NAND_BBT_LASTBLOCK) {
467 startblock = numblocks * (chip + 1) - 1;
468 dir = -1;
469 } else {
470 startblock = chip * numblocks;
471 dir = 1;
474 for (i = 0; i < td->maxblocks; i++) {
475 int block = startblock + dir * i;
476 /* Check, if the block is bad */
477 switch ((this->bbt[block >> 2] >> (2 * (block & 0x03))) & 0x03) {
478 case 0x01:
479 case 0x03:
480 continue;
482 page = block << (this->bbt_erase_shift - this->page_shift);
483 /* Check, if the block is used by the mirror table */
484 if (!md || md->pages[chip] != page)
485 goto write;
487 printk (KERN_ERR "No space left to write bad block table\n");
488 return -ENOSPC;
489 write:
491 /* Set up shift count and masks for the flash table */
492 bits = td->options & NAND_BBT_NRBITS_MSK;
493 switch (bits) {
494 case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01; msk[2] = ~rcode; msk[3] = 0x01; break;
495 case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01; msk[2] = ~rcode; msk[3] = 0x03; break;
496 case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C; msk[2] = ~rcode; msk[3] = 0x0f; break;
497 case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F; msk[2] = ~rcode; msk[3] = 0xff; break;
498 default: return -EINVAL;
501 bbtoffs = chip * (numblocks >> 2);
503 to = ((loff_t) page) << this->page_shift;
505 memcpy (&oobinfo, this->autooob, sizeof(oobinfo));
506 oobinfo.useecc = MTD_NANDECC_PLACEONLY;
508 /* Must we save the block contents ? */
509 if (td->options & NAND_BBT_SAVECONTENT) {
510 /* Make it block aligned */
511 to &= ~((loff_t) ((1 << this->bbt_erase_shift) - 1));
512 len = 1 << this->bbt_erase_shift;
513 res = mtd->read_ecc (mtd, to, len, &retlen, buf, &buf[len], &oobinfo);
514 if (res < 0) {
515 if (retlen != len) {
516 printk (KERN_INFO "nand_bbt: Error reading block for writing the bad block table\n");
517 return res;
519 printk (KERN_WARNING "nand_bbt: ECC error while reading block for writing bad block table\n");
521 /* Calc the byte offset in the buffer */
522 pageoffs = page - (int)(to >> this->page_shift);
523 offs = pageoffs << this->page_shift;
524 /* Preset the bbt area with 0xff */
525 memset (&buf[offs], 0xff, (size_t)(numblocks >> sft));
526 /* Preset the bbt's oob area with 0xff */
527 memset (&buf[len + pageoffs * mtd->oobsize], 0xff,
528 ((len >> this->page_shift) - pageoffs) * mtd->oobsize);
529 if (td->options & NAND_BBT_VERSION) {
530 buf[len + (pageoffs * mtd->oobsize) + td->veroffs] = td->version[chip];
532 } else {
533 /* Calc length */
534 len = (size_t) (numblocks >> sft);
535 /* Make it page aligned ! */
536 len = (len + (mtd->oobblock-1)) & ~(mtd->oobblock-1);
537 /* Preset the buffer with 0xff */
538 memset (buf, 0xff, len + (len >> this->page_shift) * mtd->oobsize);
539 offs = 0;
540 /* Pattern is located in oob area of first page */
541 memcpy (&buf[len + td->offs], td->pattern, td->len);
542 if (td->options & NAND_BBT_VERSION) {
543 buf[len + td->veroffs] = td->version[chip];
547 /* walk through the memory table */
548 for (i = 0; i < numblocks; ) {
549 uint8_t dat;
550 dat = this->bbt[bbtoffs + (i >> 2)];
551 for (j = 0; j < 4; j++ , i++) {
552 int sftcnt = (i << (3 - sft)) & sftmsk;
553 /* Do not store the reserved bbt blocks ! */
554 buf[offs + (i >> sft)] &= ~(msk[dat & 0x03] << sftcnt);
555 dat >>= 2;
559 memset (&einfo, 0, sizeof (einfo));
560 einfo.mtd = mtd;
561 einfo.addr = (unsigned long) to;
562 einfo.len = 1 << this->bbt_erase_shift;
563 res = nand_erase_nand (mtd, &einfo, 1);
564 if (res < 0) {
565 printk (KERN_WARNING "nand_bbt: Error during block erase: %d\n", res);
566 return res;
569 res = mtd->write_ecc (mtd, to, len, &retlen, buf, &buf[len], &oobinfo);
570 if (res < 0) {
571 printk (KERN_WARNING "nand_bbt: Error while writing bad block table %d\n", res);
572 return res;
574 printk (KERN_DEBUG "Bad block table written to 0x%08x, version 0x%02X\n",
575 (unsigned int) to, td->version[chip]);
577 /* Mark it as used */
578 td->pages[chip] = page;
580 return 0;
584 * nand_memory_bbt - [GENERIC] create a memory based bad block table
585 * @mtd: MTD device structure
586 * @bd: descriptor for the good/bad block search pattern
588 * The function creates a memory based bbt by scanning the device
589 * for manufacturer / software marked good / bad blocks
591 static int nand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
593 struct nand_chip *this = mtd->priv;
595 /* Ensure that we only scan for the pattern and nothing else */
596 bd->options = 0;
597 create_bbt (mtd, this->data_buf, bd, -1);
598 return 0;
602 * check_create - [GENERIC] create and write bbt(s) if neccecary
603 * @mtd: MTD device structure
604 * @buf: temporary buffer
605 * @bd: descriptor for the good/bad block search pattern
607 * The function checks the results of the previous call to read_bbt
608 * and creates / updates the bbt(s) if neccecary
609 * Creation is neccecary if no bbt was found for the chip/device
610 * Update is neccecary if one of the tables is missing or the
611 * version nr. of one table is less than the other
613 static int check_create (struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd)
615 int i, chips, writeops, chipsel, res;
616 struct nand_chip *this = mtd->priv;
617 struct nand_bbt_descr *td = this->bbt_td;
618 struct nand_bbt_descr *md = this->bbt_md;
619 struct nand_bbt_descr *rd, *rd2;
621 /* Do we have a bbt per chip ? */
622 if (td->options & NAND_BBT_PERCHIP)
623 chips = this->numchips;
624 else
625 chips = 1;
627 for (i = 0; i < chips; i++) {
628 writeops = 0;
629 rd = NULL;
630 rd2 = NULL;
631 /* Per chip or per device ? */
632 chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
633 /* Mirrored table avilable ? */
634 if (md) {
635 if (td->pages[i] == -1 && md->pages[i] == -1) {
636 writeops = 0x03;
637 goto create;
640 if (td->pages[i] == -1) {
641 rd = md;
642 td->version[i] = md->version[i];
643 writeops = 1;
644 goto writecheck;
647 if (md->pages[i] == -1) {
648 rd = td;
649 md->version[i] = td->version[i];
650 writeops = 2;
651 goto writecheck;
654 if (td->version[i] == md->version[i]) {
655 rd = td;
656 if (!(td->options & NAND_BBT_VERSION))
657 rd2 = md;
658 goto writecheck;
661 if (((int8_t) (td->version[i] - md->version[i])) > 0) {
662 rd = td;
663 md->version[i] = td->version[i];
664 writeops = 2;
665 } else {
666 rd = md;
667 td->version[i] = md->version[i];
668 writeops = 1;
671 goto writecheck;
673 } else {
674 if (td->pages[i] == -1) {
675 writeops = 0x01;
676 goto create;
678 rd = td;
679 goto writecheck;
681 create:
682 /* Create the bad block table by scanning the device ? */
683 if (!(td->options & NAND_BBT_CREATE))
684 continue;
686 /* Create the table in memory by scanning the chip(s) */
687 create_bbt (mtd, buf, bd, chipsel);
689 td->version[i] = 1;
690 if (md)
691 md->version[i] = 1;
692 writecheck:
693 /* read back first ? */
694 if (rd)
695 read_abs_bbt (mtd, buf, rd, chipsel);
696 /* If they weren't versioned, read both. */
697 if (rd2)
698 read_abs_bbt (mtd, buf, rd2, chipsel);
700 /* Write the bad block table to the device ? */
701 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
702 res = write_bbt (mtd, buf, td, md, chipsel);
703 if (res < 0)
704 return res;
707 /* Write the mirror bad block table to the device ? */
708 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
709 res = write_bbt (mtd, buf, md, td, chipsel);
710 if (res < 0)
711 return res;
714 return 0;
718 * mark_bbt_regions - [GENERIC] mark the bad block table regions
719 * @mtd: MTD device structure
720 * @td: bad block table descriptor
722 * The bad block table regions are marked as "bad" to prevent
723 * accidental erasures / writes. The regions are identified by
724 * the mark 0x02.
726 static void mark_bbt_region (struct mtd_info *mtd, struct nand_bbt_descr *td)
728 struct nand_chip *this = mtd->priv;
729 int i, j, chips, block, nrblocks, update;
730 uint8_t oldval, newval;
732 /* Do we have a bbt per chip ? */
733 if (td->options & NAND_BBT_PERCHIP) {
734 chips = this->numchips;
735 nrblocks = (int)(this->chipsize >> this->bbt_erase_shift);
736 } else {
737 chips = 1;
738 nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
741 for (i = 0; i < chips; i++) {
742 if ((td->options & NAND_BBT_ABSPAGE) ||
743 !(td->options & NAND_BBT_WRITE)) {
744 if (td->pages[i] == -1) continue;
745 block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
746 block <<= 1;
747 oldval = this->bbt[(block >> 3)];
748 newval = oldval | (0x2 << (block & 0x06));
749 this->bbt[(block >> 3)] = newval;
750 if ((oldval != newval) && td->reserved_block_code)
751 nand_update_bbt(mtd, block << (this->bbt_erase_shift - 1));
752 continue;
754 update = 0;
755 if (td->options & NAND_BBT_LASTBLOCK)
756 block = ((i + 1) * nrblocks) - td->maxblocks;
757 else
758 block = i * nrblocks;
759 block <<= 1;
760 for (j = 0; j < td->maxblocks; j++) {
761 oldval = this->bbt[(block >> 3)];
762 newval = oldval | (0x2 << (block & 0x06));
763 this->bbt[(block >> 3)] = newval;
764 if (oldval != newval) update = 1;
765 block += 2;
767 /* If we want reserved blocks to be recorded to flash, and some
768 new ones have been marked, then we need to update the stored
769 bbts. This should only happen once. */
770 if (update && td->reserved_block_code)
771 nand_update_bbt(mtd, (block - 2) << (this->bbt_erase_shift - 1));
776 * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
777 * @mtd: MTD device structure
778 * @bd: descriptor for the good/bad block search pattern
780 * The function checks, if a bad block table(s) is/are already
781 * available. If not it scans the device for manufacturer
782 * marked good / bad blocks and writes the bad block table(s) to
783 * the selected place.
785 * The bad block table memory is allocated here. It must be freed
786 * by calling the nand_free_bbt function.
789 int nand_scan_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
791 struct nand_chip *this = mtd->priv;
792 int len, res = 0;
793 uint8_t *buf;
794 struct nand_bbt_descr *td = this->bbt_td;
795 struct nand_bbt_descr *md = this->bbt_md;
797 len = mtd->size >> (this->bbt_erase_shift + 2);
798 /* Allocate memory (2bit per block) */
799 this->bbt = (uint8_t *) kmalloc (len, GFP_KERNEL);
800 if (!this->bbt) {
801 printk (KERN_ERR "nand_scan_bbt: Out of memory\n");
802 return -ENOMEM;
804 /* Clear the memory bad block table */
805 memset (this->bbt, 0x00, len);
807 /* If no primary table decriptor is given, scan the device
808 * to build a memory based bad block table
810 if (!td)
811 return nand_memory_bbt(mtd, bd);
813 /* Allocate a temporary buffer for one eraseblock incl. oob */
814 len = (1 << this->bbt_erase_shift);
815 len += (len >> this->page_shift) * mtd->oobsize;
816 buf = kmalloc (len, GFP_KERNEL);
817 if (!buf) {
818 printk (KERN_ERR "nand_bbt: Out of memory\n");
819 kfree (this->bbt);
820 this->bbt = NULL;
821 return -ENOMEM;
824 /* Is the bbt at a given page ? */
825 if (td->options & NAND_BBT_ABSPAGE) {
826 res = read_abs_bbts (mtd, buf, td, md);
827 } else {
828 /* Search the bad block table using a pattern in oob */
829 res = search_read_bbts (mtd, buf, td, md);
832 if (res)
833 res = check_create (mtd, buf, bd);
835 /* Prevent the bbt regions from erasing / writing */
836 mark_bbt_region (mtd, td);
837 if (md)
838 mark_bbt_region (mtd, md);
840 kfree (buf);
841 return res;
846 * nand_update_bbt - [NAND Interface] update bad block table(s)
847 * @mtd: MTD device structure
848 * @offs: the offset of the newly marked block
850 * The function updates the bad block table(s)
852 int nand_update_bbt (struct mtd_info *mtd, loff_t offs)
854 struct nand_chip *this = mtd->priv;
855 int len, res = 0, writeops = 0;
856 int chip, chipsel;
857 uint8_t *buf;
858 struct nand_bbt_descr *td = this->bbt_td;
859 struct nand_bbt_descr *md = this->bbt_md;
861 if (!this->bbt || !td)
862 return -EINVAL;
864 len = mtd->size >> (this->bbt_erase_shift + 2);
865 /* Allocate a temporary buffer for one eraseblock incl. oob */
866 len = (1 << this->bbt_erase_shift);
867 len += (len >> this->page_shift) * mtd->oobsize;
868 buf = kmalloc (len, GFP_KERNEL);
869 if (!buf) {
870 printk (KERN_ERR "nand_update_bbt: Out of memory\n");
871 return -ENOMEM;
874 writeops = md != NULL ? 0x03 : 0x01;
876 /* Do we have a bbt per chip ? */
877 if (td->options & NAND_BBT_PERCHIP) {
878 chip = (int) (offs >> this->chip_shift);
879 chipsel = chip;
880 } else {
881 chip = 0;
882 chipsel = -1;
885 td->version[chip]++;
886 if (md)
887 md->version[chip]++;
889 /* Write the bad block table to the device ? */
890 if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
891 res = write_bbt (mtd, buf, td, md, chipsel);
892 if (res < 0)
893 goto out;
895 /* Write the mirror bad block table to the device ? */
896 if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
897 res = write_bbt (mtd, buf, md, td, chipsel);
900 out:
901 kfree (buf);
902 return res;
905 /* Define some generic bad / good block scan pattern which are used
906 * while scanning a device for factory marked good / bad blocks
908 * The memory based patterns just
910 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
912 static struct nand_bbt_descr smallpage_memorybased = {
913 .options = 0,
914 .offs = 5,
915 .len = 1,
916 .pattern = scan_ff_pattern
919 static struct nand_bbt_descr largepage_memorybased = {
920 .options = 0,
921 .offs = 0,
922 .len = 2,
923 .pattern = scan_ff_pattern
926 static struct nand_bbt_descr smallpage_flashbased = {
927 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
928 .offs = 5,
929 .len = 1,
930 .pattern = scan_ff_pattern
933 static struct nand_bbt_descr largepage_flashbased = {
934 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
935 .offs = 0,
936 .len = 2,
937 .pattern = scan_ff_pattern
940 static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };
942 static struct nand_bbt_descr agand_flashbased = {
943 .options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
944 .offs = 0x20,
945 .len = 6,
946 .pattern = scan_agand_pattern
949 /* Generic flash bbt decriptors
951 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
952 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
954 static struct nand_bbt_descr bbt_main_descr = {
955 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
956 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
957 .offs = 8,
958 .len = 4,
959 .veroffs = 12,
960 .maxblocks = 4,
961 .pattern = bbt_pattern
964 static struct nand_bbt_descr bbt_mirror_descr = {
965 .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
966 | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
967 .offs = 8,
968 .len = 4,
969 .veroffs = 12,
970 .maxblocks = 4,
971 .pattern = mirror_pattern
975 * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
976 * @mtd: MTD device structure
978 * This function selects the default bad block table
979 * support for the device and calls the nand_scan_bbt function
982 int nand_default_bbt (struct mtd_info *mtd)
984 struct nand_chip *this = mtd->priv;
986 /* Default for AG-AND. We must use a flash based
987 * bad block table as the devices have factory marked
988 * _good_ blocks. Erasing those blocks leads to loss
989 * of the good / bad information, so we _must_ store
990 * this information in a good / bad table during
991 * startup
993 if (this->options & NAND_IS_AND) {
994 /* Use the default pattern descriptors */
995 if (!this->bbt_td) {
996 this->bbt_td = &bbt_main_descr;
997 this->bbt_md = &bbt_mirror_descr;
999 this->options |= NAND_USE_FLASH_BBT;
1000 return nand_scan_bbt (mtd, &agand_flashbased);
1003 /* Is a flash based bad block table requested ? */
1004 if (this->options & NAND_USE_FLASH_BBT) {
1005 /* Use the default pattern descriptors */
1006 if (!this->bbt_td) {
1007 this->bbt_td = &bbt_main_descr;
1008 this->bbt_md = &bbt_mirror_descr;
1010 if (mtd->oobblock > 512)
1011 return nand_scan_bbt (mtd, &largepage_flashbased);
1012 else
1013 return nand_scan_bbt (mtd, &smallpage_flashbased);
1014 } else {
1015 this->bbt_td = NULL;
1016 this->bbt_md = NULL;
1017 if (mtd->oobblock > 512)
1018 return nand_scan_bbt (mtd, &largepage_memorybased);
1019 else
1020 return nand_scan_bbt (mtd, &smallpage_memorybased);
1025 * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1026 * @mtd: MTD device structure
1027 * @offs: offset in the device
1028 * @allowbbt: allow access to bad block table region
1031 int nand_isbad_bbt (struct mtd_info *mtd, loff_t offs, int allowbbt)
1033 struct nand_chip *this = mtd->priv;
1034 int block;
1035 uint8_t res;
1037 /* Get block number * 2 */
1038 block = (int) (offs >> (this->bbt_erase_shift - 1));
1039 res = (this->bbt[block >> 3] >> (block & 0x06)) & 0x03;
1041 DEBUG (MTD_DEBUG_LEVEL2, "nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1042 (unsigned int)offs, res, block >> 1);
1044 switch ((int)res) {
1045 case 0x00: return 0;
1046 case 0x01: return 1;
1047 case 0x02: return allowbbt ? 0 : 1;
1049 return 1;
1052 EXPORT_SYMBOL (nand_scan_bbt);
1053 EXPORT_SYMBOL (nand_default_bbt);