xref: /linux/drivers/mtd/nand/raw/nand_bbt.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Overview:
4  *   Bad block table support for the NAND driver
5  *
6  *  Copyright © 2004 Thomas Gleixner (tglx@linutronix.de)
7  *
8  * Description:
9  *
10  * When nand_scan_bbt is called, then it tries to find the bad block table
11  * depending on the options in the BBT descriptor(s). If no flash based BBT
12  * (NAND_BBT_USE_FLASH) is specified then the device is scanned for factory
13  * marked good / bad blocks. This information is used to create a memory BBT.
14  * Once a new bad block is discovered then the "factory" information is updated
15  * on the device.
16  * If a flash based BBT is specified then the function first tries to find the
17  * BBT on flash. If a BBT is found then the contents are read and the memory
18  * based BBT is created. If a mirrored BBT is selected then the mirror is
19  * searched too and the versions are compared. If the mirror has a greater
20  * version number, then the mirror BBT is used to build the memory based BBT.
21  * If the tables are not versioned, then we "or" the bad block information.
22  * If one of the BBTs is out of date or does not exist it is (re)created.
23  * If no BBT exists at all then the device is scanned for factory marked
24  * good / bad blocks and the bad block tables are created.
25  *
26  * For manufacturer created BBTs like the one found on M-SYS DOC devices
27  * the BBT is searched and read but never created
28  *
29  * The auto generated bad block table is located in the last good blocks
30  * of the device. The table is mirrored, so it can be updated eventually.
31  * The table is marked in the OOB area with an ident pattern and a version
32  * number which indicates which of both tables is more up to date. If the NAND
33  * controller needs the complete OOB area for the ECC information then the
34  * option NAND_BBT_NO_OOB should be used (along with NAND_BBT_USE_FLASH, of
35  * course): it moves the ident pattern and the version byte into the data area
36  * and the OOB area will remain untouched.
37  *
38  * The table uses 2 bits per block
39  * 11b:		block is good
40  * 00b:		block is factory marked bad
41  * 01b, 10b:	block is marked bad due to wear
42  *
43  * The memory bad block table uses the following scheme:
44  * 00b:		block is good
45  * 01b:		block is marked bad due to wear
46  * 10b:		block is reserved (to protect the bbt area)
47  * 11b:		block is factory marked bad
48  *
49  * Multichip devices like DOC store the bad block info per floor.
50  *
51  * Following assumptions are made:
52  * - bbts start at a page boundary, if autolocated on a block boundary
53  * - the space necessary for a bbt in FLASH does not exceed a block boundary
54  */
55 
56 #include <linux/slab.h>
57 #include <linux/types.h>
58 #include <linux/mtd/mtd.h>
59 #include <linux/mtd/bbm.h>
60 #include <linux/bitops.h>
61 #include <linux/delay.h>
62 #include <linux/vmalloc.h>
63 #include <linux/export.h>
64 #include <linux/string.h>
65 
66 #include "internals.h"
67 
68 #define BBT_BLOCK_GOOD		0x00
69 #define BBT_BLOCK_WORN		0x01
70 #define BBT_BLOCK_RESERVED	0x02
71 #define BBT_BLOCK_FACTORY_BAD	0x03
72 
73 #define BBT_ENTRY_MASK		0x03
74 #define BBT_ENTRY_SHIFT		2
75 
bbt_get_entry(struct nand_chip * chip,int block)76 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
77 {
78 	uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
79 	entry >>= (block & BBT_ENTRY_MASK) * 2;
80 	return entry & BBT_ENTRY_MASK;
81 }
82 
bbt_mark_entry(struct nand_chip * chip,int block,uint8_t mark)83 static inline void bbt_mark_entry(struct nand_chip *chip, int block,
84 		uint8_t mark)
85 {
86 	uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);
87 	chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;
88 }
89 
check_pattern_no_oob(uint8_t * buf,struct nand_bbt_descr * td)90 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
91 {
92 	if (memcmp(buf, td->pattern, td->len))
93 		return -1;
94 	return 0;
95 }
96 
97 /**
98  * check_pattern - [GENERIC] check if a pattern is in the buffer
99  * @buf: the buffer to search
100  * @len: the length of buffer to search
101  * @paglen: the pagelength
102  * @td: search pattern descriptor
103  *
104  * Check for a pattern at the given place. Used to search bad block tables and
105  * good / bad block identifiers.
106  */
check_pattern(uint8_t * buf,int len,int paglen,struct nand_bbt_descr * td)107 static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
108 {
109 	if (td->options & NAND_BBT_NO_OOB)
110 		return check_pattern_no_oob(buf, td);
111 
112 	/* Compare the pattern */
113 	if (memcmp(buf + paglen + td->offs, td->pattern, td->len))
114 		return -1;
115 
116 	return 0;
117 }
118 
119 /**
120  * check_short_pattern - [GENERIC] check if a pattern is in the buffer
121  * @buf: the buffer to search
122  * @td:	search pattern descriptor
123  *
124  * Check for a pattern at the given place. Used to search bad block tables and
125  * good / bad block identifiers. Same as check_pattern, but no optional empty
126  * check.
127  */
check_short_pattern(uint8_t * buf,struct nand_bbt_descr * td)128 static int check_short_pattern(uint8_t *buf, struct nand_bbt_descr *td)
129 {
130 	/* Compare the pattern */
131 	if (memcmp(buf + td->offs, td->pattern, td->len))
132 		return -1;
133 	return 0;
134 }
135 
136 /**
137  * add_marker_len - compute the length of the marker in data area
138  * @td: BBT descriptor used for computation
139  *
140  * The length will be 0 if the marker is located in OOB area.
141  */
add_marker_len(struct nand_bbt_descr * td)142 static u32 add_marker_len(struct nand_bbt_descr *td)
143 {
144 	u32 len;
145 
146 	if (!(td->options & NAND_BBT_NO_OOB))
147 		return 0;
148 
149 	len = td->len;
150 	if (td->options & NAND_BBT_VERSION)
151 		len++;
152 	return len;
153 }
154 
155 /**
156  * read_bbt - [GENERIC] Read the bad block table starting from page
157  * @this: NAND chip object
158  * @buf: temporary buffer
159  * @page: the starting page
160  * @num: the number of bbt descriptors to read
161  * @td: the bbt describtion table
162  * @offs: block number offset in the table
163  *
164  * Read the bad block table starting from page.
165  */
read_bbt(struct nand_chip * this,uint8_t * buf,int page,int num,struct nand_bbt_descr * td,int offs)166 static int read_bbt(struct nand_chip *this, uint8_t *buf, int page, int num,
167 		    struct nand_bbt_descr *td, int offs)
168 {
169 	struct mtd_info *mtd = nand_to_mtd(this);
170 	int res, ret = 0, i, j, act = 0;
171 	size_t retlen, len, totlen;
172 	loff_t from;
173 	int bits = td->options & NAND_BBT_NRBITS_MSK;
174 	uint8_t msk = (uint8_t)((1 << bits) - 1);
175 	u32 marker_len;
176 	int reserved_block_code = td->reserved_block_code;
177 
178 	totlen = (num * bits) >> 3;
179 	marker_len = add_marker_len(td);
180 	from = ((loff_t)page) << this->page_shift;
181 
182 	while (totlen) {
183 		len = min(totlen, (size_t)(1 << this->bbt_erase_shift));
184 		if (marker_len) {
185 			/*
186 			 * In case the BBT marker is not in the OOB area it
187 			 * will be just in the first page.
188 			 */
189 			len -= marker_len;
190 			from += marker_len;
191 			marker_len = 0;
192 		}
193 		res = mtd_read(mtd, from, len, &retlen, buf);
194 		if (res < 0) {
195 			if (mtd_is_eccerr(res)) {
196 				pr_info("nand_bbt: ECC error in BBT at 0x%012llx\n",
197 					from & ~mtd->writesize);
198 				return res;
199 			} else if (mtd_is_bitflip(res)) {
200 				pr_info("nand_bbt: corrected error in BBT at 0x%012llx\n",
201 					from & ~mtd->writesize);
202 				ret = res;
203 			} else {
204 				pr_info("nand_bbt: error reading BBT\n");
205 				return res;
206 			}
207 		}
208 
209 		/* Analyse data */
210 		for (i = 0; i < len; i++) {
211 			uint8_t dat = buf[i];
212 			for (j = 0; j < 8; j += bits, act++) {
213 				uint8_t tmp = (dat >> j) & msk;
214 				if (tmp == msk)
215 					continue;
216 				if (reserved_block_code && (tmp == reserved_block_code)) {
217 					pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
218 						 (loff_t)(offs + act) <<
219 						 this->bbt_erase_shift);
220 					bbt_mark_entry(this, offs + act,
221 							BBT_BLOCK_RESERVED);
222 					mtd->ecc_stats.bbtblocks++;
223 					continue;
224 				}
225 				/*
226 				 * Leave it for now, if it's matured we can
227 				 * move this message to pr_debug.
228 				 */
229 				pr_info("nand_read_bbt: bad block at 0x%012llx\n",
230 					 (loff_t)(offs + act) <<
231 					 this->bbt_erase_shift);
232 				/* Factory marked bad or worn out? */
233 				if (tmp == 0)
234 					bbt_mark_entry(this, offs + act,
235 							BBT_BLOCK_FACTORY_BAD);
236 				else
237 					bbt_mark_entry(this, offs + act,
238 							BBT_BLOCK_WORN);
239 				mtd->ecc_stats.badblocks++;
240 			}
241 		}
242 		totlen -= len;
243 		from += len;
244 	}
245 	return ret;
246 }
247 
248 /**
249  * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
250  * @this: NAND chip object
251  * @buf: temporary buffer
252  * @td: descriptor for the bad block table
253  * @chip: read the table for a specific chip, -1 read all chips; applies only if
254  *        NAND_BBT_PERCHIP option is set
255  *
256  * Read the bad block table for all chips starting at a given page. We assume
257  * that the bbt bits are in consecutive order.
258  */
read_abs_bbt(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * td,int chip)259 static int read_abs_bbt(struct nand_chip *this, uint8_t *buf,
260 			struct nand_bbt_descr *td, int chip)
261 {
262 	struct mtd_info *mtd = nand_to_mtd(this);
263 	u64 targetsize = nanddev_target_size(&this->base);
264 	int res = 0, i;
265 
266 	if (td->options & NAND_BBT_PERCHIP) {
267 		int offs = 0;
268 		for (i = 0; i < nanddev_ntargets(&this->base); i++) {
269 			if (chip == -1 || chip == i)
270 				res = read_bbt(this, buf, td->pages[i],
271 					targetsize >> this->bbt_erase_shift,
272 					td, offs);
273 			if (res)
274 				return res;
275 			offs += targetsize >> this->bbt_erase_shift;
276 		}
277 	} else {
278 		res = read_bbt(this, buf, td->pages[0],
279 				mtd->size >> this->bbt_erase_shift, td, 0);
280 		if (res)
281 			return res;
282 	}
283 	return 0;
284 }
285 
286 /* BBT marker is in the first page, no OOB */
scan_read_data(struct nand_chip * this,uint8_t * buf,loff_t offs,struct nand_bbt_descr * td)287 static int scan_read_data(struct nand_chip *this, uint8_t *buf, loff_t offs,
288 			  struct nand_bbt_descr *td)
289 {
290 	struct mtd_info *mtd = nand_to_mtd(this);
291 	size_t retlen;
292 	size_t len;
293 
294 	len = td->len;
295 	if (td->options & NAND_BBT_VERSION)
296 		len++;
297 
298 	return mtd_read(mtd, offs, len, &retlen, buf);
299 }
300 
301 /**
302  * scan_read_oob - [GENERIC] Scan data+OOB region to buffer
303  * @this: NAND chip object
304  * @buf: temporary buffer
305  * @offs: offset at which to scan
306  * @len: length of data region to read
307  *
308  * Scan read data from data+OOB. May traverse multiple pages, interleaving
309  * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest"
310  * ECC condition (error or bitflip). May quit on the first (non-ECC) error.
311  */
scan_read_oob(struct nand_chip * this,uint8_t * buf,loff_t offs,size_t len)312 static int scan_read_oob(struct nand_chip *this, uint8_t *buf, loff_t offs,
313 			 size_t len)
314 {
315 	struct mtd_info *mtd = nand_to_mtd(this);
316 	struct mtd_oob_ops ops = { };
317 	int res, ret = 0;
318 
319 	ops.mode = MTD_OPS_PLACE_OOB;
320 	ops.ooboffs = 0;
321 	ops.ooblen = mtd->oobsize;
322 
323 	while (len > 0) {
324 		ops.datbuf = buf;
325 		ops.len = min(len, (size_t)mtd->writesize);
326 		ops.oobbuf = buf + ops.len;
327 
328 		res = mtd_read_oob(mtd, offs, &ops);
329 		if (res) {
330 			if (!mtd_is_bitflip_or_eccerr(res))
331 				return res;
332 			else if (mtd_is_eccerr(res) || !ret)
333 				ret = res;
334 		}
335 
336 		buf += mtd->oobsize + mtd->writesize;
337 		len -= mtd->writesize;
338 		offs += mtd->writesize;
339 	}
340 	return ret;
341 }
342 
scan_read(struct nand_chip * this,uint8_t * buf,loff_t offs,size_t len,struct nand_bbt_descr * td)343 static int scan_read(struct nand_chip *this, uint8_t *buf, loff_t offs,
344 		     size_t len, struct nand_bbt_descr *td)
345 {
346 	if (td->options & NAND_BBT_NO_OOB)
347 		return scan_read_data(this, buf, offs, td);
348 	else
349 		return scan_read_oob(this, buf, offs, len);
350 }
351 
352 /* Scan write data with oob to flash */
scan_write_bbt(struct nand_chip * this,loff_t offs,size_t len,uint8_t * buf,uint8_t * oob)353 static int scan_write_bbt(struct nand_chip *this, loff_t offs, size_t len,
354 			  uint8_t *buf, uint8_t *oob)
355 {
356 	struct mtd_info *mtd = nand_to_mtd(this);
357 	struct mtd_oob_ops ops = { };
358 
359 	ops.mode = MTD_OPS_PLACE_OOB;
360 	ops.ooboffs = 0;
361 	ops.ooblen = mtd->oobsize;
362 	ops.datbuf = buf;
363 	ops.oobbuf = oob;
364 	ops.len = len;
365 
366 	return mtd_write_oob(mtd, offs, &ops);
367 }
368 
bbt_get_ver_offs(struct nand_chip * this,struct nand_bbt_descr * td)369 static u32 bbt_get_ver_offs(struct nand_chip *this, struct nand_bbt_descr *td)
370 {
371 	struct mtd_info *mtd = nand_to_mtd(this);
372 	u32 ver_offs = td->veroffs;
373 
374 	if (!(td->options & NAND_BBT_NO_OOB))
375 		ver_offs += mtd->writesize;
376 	return ver_offs;
377 }
378 
379 /**
380  * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
381  * @this: NAND chip object
382  * @buf: temporary buffer
383  * @td: descriptor for the bad block table
384  * @md:	descriptor for the bad block table mirror
385  *
386  * Read the bad block table(s) for all chips starting at a given page. We
387  * assume that the bbt bits are in consecutive order.
388  */
read_abs_bbts(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * td,struct nand_bbt_descr * md)389 static void read_abs_bbts(struct nand_chip *this, uint8_t *buf,
390 			  struct nand_bbt_descr *td, struct nand_bbt_descr *md)
391 {
392 	struct mtd_info *mtd = nand_to_mtd(this);
393 
394 	/* Read the primary version, if available */
395 	if (td->options & NAND_BBT_VERSION) {
396 		scan_read(this, buf, (loff_t)td->pages[0] << this->page_shift,
397 			  mtd->writesize, td);
398 		td->version[0] = buf[bbt_get_ver_offs(this, td)];
399 		pr_info("Bad block table at page %d, version 0x%02X\n",
400 			 td->pages[0], td->version[0]);
401 	}
402 
403 	/* Read the mirror version, if available */
404 	if (md && (md->options & NAND_BBT_VERSION)) {
405 		scan_read(this, buf, (loff_t)md->pages[0] << this->page_shift,
406 			  mtd->writesize, md);
407 		md->version[0] = buf[bbt_get_ver_offs(this, md)];
408 		pr_info("Bad block table at page %d, version 0x%02X\n",
409 			 md->pages[0], md->version[0]);
410 	}
411 }
412 
413 /* Scan a given block partially */
scan_block_fast(struct nand_chip * this,struct nand_bbt_descr * bd,loff_t offs,uint8_t * buf)414 static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
415 			   loff_t offs, uint8_t *buf)
416 {
417 	struct mtd_info *mtd = nand_to_mtd(this);
418 
419 	struct mtd_oob_ops ops = { };
420 	int ret, page_offset;
421 
422 	ops.ooblen = mtd->oobsize;
423 	ops.oobbuf = buf;
424 	ops.ooboffs = 0;
425 	ops.datbuf = NULL;
426 	ops.mode = MTD_OPS_PLACE_OOB;
427 
428 	page_offset = nand_bbm_get_next_page(this, 0);
429 
430 	while (page_offset >= 0) {
431 		/*
432 		 * Read the full oob until read_oob is fixed to handle single
433 		 * byte reads for 16 bit buswidth.
434 		 */
435 		ret = mtd_read_oob(mtd, offs + (page_offset * mtd->writesize),
436 				   &ops);
437 		/* Ignore ECC errors when checking for BBM */
438 		if (ret && !mtd_is_bitflip_or_eccerr(ret))
439 			return ret;
440 
441 		if (check_short_pattern(buf, bd))
442 			return 1;
443 
444 		page_offset = nand_bbm_get_next_page(this, page_offset + 1);
445 	}
446 
447 	return 0;
448 }
449 
450 /* Check if a potential BBT block is marked as bad */
bbt_block_checkbad(struct nand_chip * this,struct nand_bbt_descr * td,loff_t offs,uint8_t * buf)451 static int bbt_block_checkbad(struct nand_chip *this, struct nand_bbt_descr *td,
452 			      loff_t offs, uint8_t *buf)
453 {
454 	struct nand_bbt_descr *bd = this->badblock_pattern;
455 
456 	/*
457 	 * No need to check for a bad BBT block if the BBM area overlaps with
458 	 * the bad block table marker area in OOB since writing a BBM here
459 	 * invalidates the bad block table marker anyway.
460 	 */
461 	if (!(td->options & NAND_BBT_NO_OOB) &&
462 	    td->offs >= bd->offs && td->offs < bd->offs + bd->len)
463 		return 0;
464 
465 	/*
466 	 * There is no point in checking for a bad block marker if writing
467 	 * such marker is not supported
468 	 */
469 	if (this->bbt_options & NAND_BBT_NO_OOB_BBM ||
470 	    this->options & NAND_NO_BBM_QUIRK)
471 		return 0;
472 
473 	if (scan_block_fast(this, bd, offs, buf) > 0)
474 		return 1;
475 
476 	return 0;
477 }
478 
479 /**
480  * create_bbt - [GENERIC] Create a bad block table by scanning the device
481  * @this: NAND chip object
482  * @buf: temporary buffer
483  * @bd: descriptor for the good/bad block search pattern
484  * @chip: create the table for a specific chip, -1 read all chips; applies only
485  *        if NAND_BBT_PERCHIP option is set
486  *
487  * Create a bad block table by scanning the device for the given good/bad block
488  * identify pattern.
489  */
create_bbt(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * bd,int chip)490 static int create_bbt(struct nand_chip *this, uint8_t *buf,
491 		      struct nand_bbt_descr *bd, int chip)
492 {
493 	u64 targetsize = nanddev_target_size(&this->base);
494 	struct mtd_info *mtd = nand_to_mtd(this);
495 	int i, numblocks, startblock;
496 	loff_t from;
497 
498 	pr_info("Scanning device for bad blocks\n");
499 
500 	if (chip == -1) {
501 		numblocks = mtd->size >> this->bbt_erase_shift;
502 		startblock = 0;
503 		from = 0;
504 	} else {
505 		if (chip >= nanddev_ntargets(&this->base)) {
506 			pr_warn("create_bbt(): chipnr (%d) > available chips (%d)\n",
507 			        chip + 1, nanddev_ntargets(&this->base));
508 			return -EINVAL;
509 		}
510 		numblocks = targetsize >> this->bbt_erase_shift;
511 		startblock = chip * numblocks;
512 		numblocks += startblock;
513 		from = (loff_t)startblock << this->bbt_erase_shift;
514 	}
515 
516 	for (i = startblock; i < numblocks; i++) {
517 		int ret;
518 
519 		BUG_ON(bd->options & NAND_BBT_NO_OOB);
520 
521 		ret = scan_block_fast(this, bd, from, buf);
522 		if (ret < 0)
523 			return ret;
524 
525 		if (ret) {
526 			bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
527 			pr_warn("Bad eraseblock %d at 0x%012llx\n",
528 				i, (unsigned long long)from);
529 			mtd->ecc_stats.badblocks++;
530 		}
531 
532 		from += (1 << this->bbt_erase_shift);
533 	}
534 	return 0;
535 }
536 
537 /**
538  * search_bbt - [GENERIC] scan the device for a specific bad block table
539  * @this: NAND chip object
540  * @buf: temporary buffer
541  * @td: descriptor for the bad block table
542  *
543  * Read the bad block table by searching for a given ident pattern. Search is
544  * preformed either from the beginning up or from the end of the device
545  * downwards. The search starts always at the start of a block. If the option
546  * NAND_BBT_PERCHIP is given, each chip is searched for a bbt, which contains
547  * the bad block information of this chip. This is necessary to provide support
548  * for certain DOC devices.
549  *
550  * The bbt ident pattern resides in the oob area of the first page in a block.
551  */
search_bbt(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * td)552 static int search_bbt(struct nand_chip *this, uint8_t *buf,
553 		      struct nand_bbt_descr *td)
554 {
555 	u64 targetsize = nanddev_target_size(&this->base);
556 	struct mtd_info *mtd = nand_to_mtd(this);
557 	int i, chips;
558 	int startblock, block, dir;
559 	int scanlen = mtd->writesize + mtd->oobsize;
560 	int bbtblocks;
561 	int blocktopage = this->bbt_erase_shift - this->page_shift;
562 
563 	/* Search direction top -> down? */
564 	if (td->options & NAND_BBT_LASTBLOCK) {
565 		startblock = (mtd->size >> this->bbt_erase_shift) - 1;
566 		dir = -1;
567 	} else {
568 		startblock = 0;
569 		dir = 1;
570 	}
571 
572 	/* Do we have a bbt per chip? */
573 	if (td->options & NAND_BBT_PERCHIP) {
574 		chips = nanddev_ntargets(&this->base);
575 		bbtblocks = targetsize >> this->bbt_erase_shift;
576 		startblock &= bbtblocks - 1;
577 	} else {
578 		chips = 1;
579 	}
580 
581 	for (i = 0; i < chips; i++) {
582 		/* Reset version information */
583 		td->version[i] = 0;
584 		td->pages[i] = -1;
585 		/* Scan the maximum number of blocks */
586 		for (block = 0; block < td->maxblocks; block++) {
587 
588 			int actblock = startblock + dir * block;
589 			loff_t offs = (loff_t)actblock << this->bbt_erase_shift;
590 
591 			/* Check if block is marked bad */
592 			if (bbt_block_checkbad(this, td, offs, buf))
593 				continue;
594 
595 			/* Read first page */
596 			scan_read(this, buf, offs, mtd->writesize, td);
597 			if (!check_pattern(buf, scanlen, mtd->writesize, td)) {
598 				td->pages[i] = actblock << blocktopage;
599 				if (td->options & NAND_BBT_VERSION) {
600 					offs = bbt_get_ver_offs(this, td);
601 					td->version[i] = buf[offs];
602 				}
603 				break;
604 			}
605 		}
606 		startblock += targetsize >> this->bbt_erase_shift;
607 	}
608 	/* Check, if we found a bbt for each requested chip */
609 	for (i = 0; i < chips; i++) {
610 		if (td->pages[i] == -1)
611 			pr_warn("Bad block table not found for chip %d\n", i);
612 		else
613 			pr_info("Bad block table found at page %d, version 0x%02X\n",
614 				td->pages[i], td->version[i]);
615 	}
616 	return 0;
617 }
618 
619 /**
620  * search_read_bbts - [GENERIC] scan the device for bad block table(s)
621  * @this: NAND chip object
622  * @buf: temporary buffer
623  * @td: descriptor for the bad block table
624  * @md: descriptor for the bad block table mirror
625  *
626  * Search and read the bad block table(s).
627  */
search_read_bbts(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * td,struct nand_bbt_descr * md)628 static void search_read_bbts(struct nand_chip *this, uint8_t *buf,
629 			     struct nand_bbt_descr *td,
630 			     struct nand_bbt_descr *md)
631 {
632 	/* Search the primary table */
633 	search_bbt(this, buf, td);
634 
635 	/* Search the mirror table */
636 	if (md)
637 		search_bbt(this, buf, md);
638 }
639 
640 /**
641  * get_bbt_block - Get the first valid eraseblock suitable to store a BBT
642  * @this: the NAND device
643  * @td: the BBT description
644  * @md: the mirror BBT descriptor
645  * @chip: the CHIP selector
646  *
647  * This functions returns a positive block number pointing a valid eraseblock
648  * suitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC if
649  * all blocks are already used of marked bad. If td->pages[chip] was already
650  * pointing to a valid block we re-use it, otherwise we search for the next
651  * valid one.
652  */
get_bbt_block(struct nand_chip * this,struct nand_bbt_descr * td,struct nand_bbt_descr * md,int chip)653 static int get_bbt_block(struct nand_chip *this, struct nand_bbt_descr *td,
654 			 struct nand_bbt_descr *md, int chip)
655 {
656 	u64 targetsize = nanddev_target_size(&this->base);
657 	int startblock, dir, page, numblocks, i;
658 
659 	/*
660 	 * There was already a version of the table, reuse the page. This
661 	 * applies for absolute placement too, as we have the page number in
662 	 * td->pages.
663 	 */
664 	if (td->pages[chip] != -1)
665 		return td->pages[chip] >>
666 				(this->bbt_erase_shift - this->page_shift);
667 
668 	numblocks = (int)(targetsize >> this->bbt_erase_shift);
669 	if (!(td->options & NAND_BBT_PERCHIP))
670 		numblocks *= nanddev_ntargets(&this->base);
671 
672 	/*
673 	 * Automatic placement of the bad block table. Search direction
674 	 * top -> down?
675 	 */
676 	if (td->options & NAND_BBT_LASTBLOCK) {
677 		startblock = numblocks * (chip + 1) - 1;
678 		dir = -1;
679 	} else {
680 		startblock = chip * numblocks;
681 		dir = 1;
682 	}
683 
684 	for (i = 0; i < td->maxblocks; i++) {
685 		int block = startblock + dir * i;
686 
687 		/* Check, if the block is bad */
688 		switch (bbt_get_entry(this, block)) {
689 		case BBT_BLOCK_WORN:
690 		case BBT_BLOCK_FACTORY_BAD:
691 			continue;
692 		}
693 
694 		page = block << (this->bbt_erase_shift - this->page_shift);
695 
696 		/* Check, if the block is used by the mirror table */
697 		if (!md || md->pages[chip] != page)
698 			return block;
699 	}
700 
701 	return -ENOSPC;
702 }
703 
704 /**
705  * mark_bbt_block_bad - Mark one of the block reserved for BBT bad
706  * @this: the NAND device
707  * @td: the BBT description
708  * @chip: the CHIP selector
709  * @block: the BBT block to mark
710  *
711  * Blocks reserved for BBT can become bad. This functions is an helper to mark
712  * such blocks as bad. It takes care of updating the in-memory BBT, marking the
713  * block as bad using a bad block marker and invalidating the associated
714  * td->pages[] entry.
715  */
mark_bbt_block_bad(struct nand_chip * this,struct nand_bbt_descr * td,int chip,int block)716 static void mark_bbt_block_bad(struct nand_chip *this,
717 			       struct nand_bbt_descr *td,
718 			       int chip, int block)
719 {
720 	loff_t to;
721 	int res;
722 
723 	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
724 
725 	to = (loff_t)block << this->bbt_erase_shift;
726 	res = nand_markbad_bbm(this, to);
727 	if (res)
728 		pr_warn("nand_bbt: error %d while marking block %d bad\n",
729 			res, block);
730 
731 	td->pages[chip] = -1;
732 }
733 
734 /**
735  * write_bbt - [GENERIC] (Re)write the bad block table
736  * @this: NAND chip object
737  * @buf: temporary buffer
738  * @td: descriptor for the bad block table
739  * @md: descriptor for the bad block table mirror
740  * @chipsel: selector for a specific chip, -1 for all
741  *
742  * (Re)write the bad block table.
743  */
write_bbt(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * td,struct nand_bbt_descr * md,int chipsel)744 static int write_bbt(struct nand_chip *this, uint8_t *buf,
745 		     struct nand_bbt_descr *td, struct nand_bbt_descr *md,
746 		     int chipsel)
747 {
748 	u64 targetsize = nanddev_target_size(&this->base);
749 	struct mtd_info *mtd = nand_to_mtd(this);
750 	struct erase_info einfo;
751 	int i, res, chip = 0;
752 	int bits, page, offs, numblocks, sft, sftmsk;
753 	int nrchips, pageoffs, ooboffs;
754 	uint8_t msk[4];
755 	uint8_t rcode = td->reserved_block_code;
756 	size_t retlen, len = 0;
757 	loff_t to;
758 	struct mtd_oob_ops ops = { };
759 
760 	ops.ooblen = mtd->oobsize;
761 	ops.ooboffs = 0;
762 	ops.datbuf = NULL;
763 	ops.mode = MTD_OPS_PLACE_OOB;
764 
765 	if (!rcode)
766 		rcode = 0xff;
767 	/* Write bad block table per chip rather than per device? */
768 	if (td->options & NAND_BBT_PERCHIP) {
769 		numblocks = (int)(targetsize >> this->bbt_erase_shift);
770 		/* Full device write or specific chip? */
771 		if (chipsel == -1) {
772 			nrchips = nanddev_ntargets(&this->base);
773 		} else {
774 			nrchips = chipsel + 1;
775 			chip = chipsel;
776 		}
777 	} else {
778 		numblocks = (int)(mtd->size >> this->bbt_erase_shift);
779 		nrchips = 1;
780 	}
781 
782 	/* Loop through the chips */
783 	while (chip < nrchips) {
784 		int block;
785 
786 		block = get_bbt_block(this, td, md, chip);
787 		if (block < 0) {
788 			pr_err("No space left to write bad block table\n");
789 			res = block;
790 			goto outerr;
791 		}
792 
793 		/*
794 		 * get_bbt_block() returns a block number, shift the value to
795 		 * get a page number.
796 		 */
797 		page = block << (this->bbt_erase_shift - this->page_shift);
798 
799 		/* Set up shift count and masks for the flash table */
800 		bits = td->options & NAND_BBT_NRBITS_MSK;
801 		msk[2] = ~rcode;
802 		switch (bits) {
803 		case 1: sft = 3; sftmsk = 0x07; msk[0] = 0x00; msk[1] = 0x01;
804 			msk[3] = 0x01;
805 			break;
806 		case 2: sft = 2; sftmsk = 0x06; msk[0] = 0x00; msk[1] = 0x01;
807 			msk[3] = 0x03;
808 			break;
809 		case 4: sft = 1; sftmsk = 0x04; msk[0] = 0x00; msk[1] = 0x0C;
810 			msk[3] = 0x0f;
811 			break;
812 		case 8: sft = 0; sftmsk = 0x00; msk[0] = 0x00; msk[1] = 0x0F;
813 			msk[3] = 0xff;
814 			break;
815 		default: return -EINVAL;
816 		}
817 
818 		to = ((loff_t)page) << this->page_shift;
819 
820 		/* Must we save the block contents? */
821 		if (td->options & NAND_BBT_SAVECONTENT) {
822 			/* Make it block aligned */
823 			to &= ~(((loff_t)1 << this->bbt_erase_shift) - 1);
824 			len = 1 << this->bbt_erase_shift;
825 			res = mtd_read(mtd, to, len, &retlen, buf);
826 			if (res < 0) {
827 				if (retlen != len) {
828 					pr_info("nand_bbt: error reading block for writing the bad block table\n");
829 					return res;
830 				}
831 				pr_warn("nand_bbt: ECC error while reading block for writing bad block table\n");
832 			}
833 			/* Read oob data */
834 			ops.ooblen = (len >> this->page_shift) * mtd->oobsize;
835 			ops.oobbuf = &buf[len];
836 			res = mtd_read_oob(mtd, to + mtd->writesize, &ops);
837 			if (res < 0 || ops.oobretlen != ops.ooblen)
838 				goto outerr;
839 
840 			/* Calc the byte offset in the buffer */
841 			pageoffs = page - (int)(to >> this->page_shift);
842 			offs = pageoffs << this->page_shift;
843 			/* Preset the bbt area with 0xff */
844 			memset(&buf[offs], 0xff, (size_t)(numblocks >> sft));
845 			ooboffs = len + (pageoffs * mtd->oobsize);
846 
847 		} else if (td->options & NAND_BBT_NO_OOB) {
848 			ooboffs = 0;
849 			offs = td->len;
850 			/* The version byte */
851 			if (td->options & NAND_BBT_VERSION)
852 				offs++;
853 			/* Calc length */
854 			len = (size_t)(numblocks >> sft);
855 			len += offs;
856 			/* Make it page aligned! */
857 			len = ALIGN(len, mtd->writesize);
858 			/* Preset the buffer with 0xff */
859 			memset(buf, 0xff, len);
860 			/* Pattern is located at the begin of first page */
861 			memcpy(buf, td->pattern, td->len);
862 		} else {
863 			/* Calc length */
864 			len = (size_t)(numblocks >> sft);
865 			/* Make it page aligned! */
866 			len = ALIGN(len, mtd->writesize);
867 			/* Preset the buffer with 0xff */
868 			memset(buf, 0xff, len +
869 			       (len >> this->page_shift)* mtd->oobsize);
870 			offs = 0;
871 			ooboffs = len;
872 			/* Pattern is located in oob area of first page */
873 			memcpy(&buf[ooboffs + td->offs], td->pattern, td->len);
874 		}
875 
876 		if (td->options & NAND_BBT_VERSION)
877 			buf[ooboffs + td->veroffs] = td->version[chip];
878 
879 		/* Walk through the memory table */
880 		for (i = 0; i < numblocks; i++) {
881 			uint8_t dat;
882 			int sftcnt = (i << (3 - sft)) & sftmsk;
883 			dat = bbt_get_entry(this, chip * numblocks + i);
884 			/* Do not store the reserved bbt blocks! */
885 			buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
886 		}
887 
888 		memset(&einfo, 0, sizeof(einfo));
889 		einfo.addr = to;
890 		einfo.len = 1 << this->bbt_erase_shift;
891 		res = nand_erase_nand(this, &einfo, 1);
892 		if (res < 0) {
893 			pr_warn("nand_bbt: error while erasing BBT block %d\n",
894 				res);
895 			mark_bbt_block_bad(this, td, chip, block);
896 			continue;
897 		}
898 
899 		res = scan_write_bbt(this, to, len, buf,
900 				     td->options & NAND_BBT_NO_OOB ?
901 				     NULL : &buf[len]);
902 		if (res < 0) {
903 			pr_warn("nand_bbt: error while writing BBT block %d\n",
904 				res);
905 			mark_bbt_block_bad(this, td, chip, block);
906 			continue;
907 		}
908 
909 		pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
910 			 (unsigned long long)to, td->version[chip]);
911 
912 		/* Mark it as used */
913 		td->pages[chip++] = page;
914 	}
915 	return 0;
916 
917  outerr:
918 	pr_warn("nand_bbt: error while writing bad block table %d\n", res);
919 	return res;
920 }
921 
922 /**
923  * nand_memory_bbt - [GENERIC] create a memory based bad block table
924  * @this: NAND chip object
925  * @bd: descriptor for the good/bad block search pattern
926  *
927  * The function creates a memory based bbt by scanning the device for
928  * manufacturer / software marked good / bad blocks.
929  */
nand_memory_bbt(struct nand_chip * this,struct nand_bbt_descr * bd)930 static inline int nand_memory_bbt(struct nand_chip *this,
931 				  struct nand_bbt_descr *bd)
932 {
933 	u8 *pagebuf = nand_get_data_buf(this);
934 
935 	return create_bbt(this, pagebuf, bd, -1);
936 }
937 
938 /**
939  * check_create - [GENERIC] create and write bbt(s) if necessary
940  * @this: the NAND device
941  * @buf: temporary buffer
942  * @bd: descriptor for the good/bad block search pattern
943  *
944  * The function checks the results of the previous call to read_bbt and creates
945  * / updates the bbt(s) if necessary. Creation is necessary if no bbt was found
946  * for the chip/device. Update is necessary if one of the tables is missing or
947  * the version nr. of one table is less than the other.
948  */
check_create(struct nand_chip * this,uint8_t * buf,struct nand_bbt_descr * bd)949 static int check_create(struct nand_chip *this, uint8_t *buf,
950 			struct nand_bbt_descr *bd)
951 {
952 	int i, chips, writeops, create, chipsel, res, res2;
953 	struct nand_bbt_descr *td = this->bbt_td;
954 	struct nand_bbt_descr *md = this->bbt_md;
955 	struct nand_bbt_descr *rd, *rd2;
956 
957 	/* Do we have a bbt per chip? */
958 	if (td->options & NAND_BBT_PERCHIP)
959 		chips = nanddev_ntargets(&this->base);
960 	else
961 		chips = 1;
962 
963 	for (i = 0; i < chips; i++) {
964 		writeops = 0;
965 		create = 0;
966 		rd = NULL;
967 		rd2 = NULL;
968 		res = res2 = 0;
969 		/* Per chip or per device? */
970 		chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1;
971 		/* Mirrored table available? */
972 		if (md) {
973 			if (td->pages[i] == -1 && md->pages[i] == -1) {
974 				create = 1;
975 				writeops = 0x03;
976 			} else if (td->pages[i] == -1) {
977 				rd = md;
978 				writeops = 0x01;
979 			} else if (md->pages[i] == -1) {
980 				rd = td;
981 				writeops = 0x02;
982 			} else if (td->version[i] == md->version[i]) {
983 				rd = td;
984 				if (!(td->options & NAND_BBT_VERSION))
985 					rd2 = md;
986 			} else if (((int8_t)(td->version[i] - md->version[i])) > 0) {
987 				rd = td;
988 				writeops = 0x02;
989 			} else {
990 				rd = md;
991 				writeops = 0x01;
992 			}
993 		} else {
994 			if (td->pages[i] == -1) {
995 				create = 1;
996 				writeops = 0x01;
997 			} else {
998 				rd = td;
999 			}
1000 		}
1001 
1002 		if (create) {
1003 			/* Create the bad block table by scanning the device? */
1004 			if (!(td->options & NAND_BBT_CREATE))
1005 				continue;
1006 
1007 			/* Create the table in memory by scanning the chip(s) */
1008 			if (!(this->bbt_options & NAND_BBT_CREATE_EMPTY))
1009 				create_bbt(this, buf, bd, chipsel);
1010 
1011 			td->version[i] = 1;
1012 			if (md)
1013 				md->version[i] = 1;
1014 		}
1015 
1016 		/* Read back first? */
1017 		if (rd) {
1018 			res = read_abs_bbt(this, buf, rd, chipsel);
1019 			if (mtd_is_eccerr(res)) {
1020 				/* Mark table as invalid */
1021 				rd->pages[i] = -1;
1022 				rd->version[i] = 0;
1023 				i--;
1024 				continue;
1025 			}
1026 		}
1027 		/* If they weren't versioned, read both */
1028 		if (rd2) {
1029 			res2 = read_abs_bbt(this, buf, rd2, chipsel);
1030 			if (mtd_is_eccerr(res2)) {
1031 				/* Mark table as invalid */
1032 				rd2->pages[i] = -1;
1033 				rd2->version[i] = 0;
1034 				i--;
1035 				continue;
1036 			}
1037 		}
1038 
1039 		/* Scrub the flash table(s)? */
1040 		if (mtd_is_bitflip(res) || mtd_is_bitflip(res2))
1041 			writeops = 0x03;
1042 
1043 		/* Update version numbers before writing */
1044 		if (md) {
1045 			td->version[i] = max(td->version[i], md->version[i]);
1046 			md->version[i] = td->version[i];
1047 		}
1048 
1049 		/* Write the bad block table to the device? */
1050 		if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) {
1051 			res = write_bbt(this, buf, td, md, chipsel);
1052 			if (res < 0)
1053 				return res;
1054 		}
1055 
1056 		/* Write the mirror bad block table to the device? */
1057 		if ((writeops & 0x02) && md && (md->options & NAND_BBT_WRITE)) {
1058 			res = write_bbt(this, buf, md, td, chipsel);
1059 			if (res < 0)
1060 				return res;
1061 		}
1062 	}
1063 	return 0;
1064 }
1065 
1066 /**
1067  * nand_update_bbt - update bad block table(s)
1068  * @this: the NAND device
1069  * @offs: the offset of the newly marked block
1070  *
1071  * The function updates the bad block table(s).
1072  */
nand_update_bbt(struct nand_chip * this,loff_t offs)1073 static int nand_update_bbt(struct nand_chip *this, loff_t offs)
1074 {
1075 	struct mtd_info *mtd = nand_to_mtd(this);
1076 	int len, res = 0;
1077 	int chip, chipsel;
1078 	uint8_t *buf;
1079 	struct nand_bbt_descr *td = this->bbt_td;
1080 	struct nand_bbt_descr *md = this->bbt_md;
1081 
1082 	if (!this->bbt || !td)
1083 		return -EINVAL;
1084 
1085 	/* Allocate a temporary buffer for one eraseblock incl. oob */
1086 	len = (1 << this->bbt_erase_shift);
1087 	len += (len >> this->page_shift) * mtd->oobsize;
1088 	buf = kmalloc(len, GFP_KERNEL);
1089 	if (!buf)
1090 		return -ENOMEM;
1091 
1092 	/* Do we have a bbt per chip? */
1093 	if (td->options & NAND_BBT_PERCHIP) {
1094 		chip = (int)(offs >> this->chip_shift);
1095 		chipsel = chip;
1096 	} else {
1097 		chip = 0;
1098 		chipsel = -1;
1099 	}
1100 
1101 	td->version[chip]++;
1102 	if (md)
1103 		md->version[chip]++;
1104 
1105 	/* Write the bad block table to the device? */
1106 	if (td->options & NAND_BBT_WRITE) {
1107 		res = write_bbt(this, buf, td, md, chipsel);
1108 		if (res < 0)
1109 			goto out;
1110 	}
1111 	/* Write the mirror bad block table to the device? */
1112 	if (md && (md->options & NAND_BBT_WRITE)) {
1113 		res = write_bbt(this, buf, md, td, chipsel);
1114 	}
1115 
1116  out:
1117 	kfree(buf);
1118 	return res;
1119 }
1120 
1121 /**
1122  * mark_bbt_region - [GENERIC] mark the bad block table regions
1123  * @this: the NAND device
1124  * @td: bad block table descriptor
1125  *
1126  * The bad block table regions are marked as "bad" to prevent accidental
1127  * erasures / writes. The regions are identified by the mark 0x02.
1128  */
mark_bbt_region(struct nand_chip * this,struct nand_bbt_descr * td)1129 static void mark_bbt_region(struct nand_chip *this, struct nand_bbt_descr *td)
1130 {
1131 	u64 targetsize = nanddev_target_size(&this->base);
1132 	struct mtd_info *mtd = nand_to_mtd(this);
1133 	int i, j, chips, block, nrblocks, update;
1134 	uint8_t oldval;
1135 
1136 	/* Do we have a bbt per chip? */
1137 	if (td->options & NAND_BBT_PERCHIP) {
1138 		chips = nanddev_ntargets(&this->base);
1139 		nrblocks = (int)(targetsize >> this->bbt_erase_shift);
1140 	} else {
1141 		chips = 1;
1142 		nrblocks = (int)(mtd->size >> this->bbt_erase_shift);
1143 	}
1144 
1145 	for (i = 0; i < chips; i++) {
1146 		if ((td->options & NAND_BBT_ABSPAGE) ||
1147 		    !(td->options & NAND_BBT_WRITE)) {
1148 			if (td->pages[i] == -1)
1149 				continue;
1150 			block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
1151 			oldval = bbt_get_entry(this, block);
1152 			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1153 			if ((oldval != BBT_BLOCK_RESERVED) &&
1154 					td->reserved_block_code)
1155 				nand_update_bbt(this, (loff_t)block <<
1156 						this->bbt_erase_shift);
1157 			continue;
1158 		}
1159 		update = 0;
1160 		if (td->options & NAND_BBT_LASTBLOCK)
1161 			block = ((i + 1) * nrblocks) - td->maxblocks;
1162 		else
1163 			block = i * nrblocks;
1164 		for (j = 0; j < td->maxblocks; j++) {
1165 			oldval = bbt_get_entry(this, block);
1166 			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
1167 			if (oldval != BBT_BLOCK_RESERVED)
1168 				update = 1;
1169 			block++;
1170 		}
1171 		/*
1172 		 * If we want reserved blocks to be recorded to flash, and some
1173 		 * new ones have been marked, then we need to update the stored
1174 		 * bbts.  This should only happen once.
1175 		 */
1176 		if (update && td->reserved_block_code)
1177 			nand_update_bbt(this, (loff_t)(block - 1) <<
1178 					this->bbt_erase_shift);
1179 	}
1180 }
1181 
1182 /**
1183  * verify_bbt_descr - verify the bad block description
1184  * @this: the NAND device
1185  * @bd: the table to verify
1186  *
1187  * This functions performs a few sanity checks on the bad block description
1188  * table.
1189  */
verify_bbt_descr(struct nand_chip * this,struct nand_bbt_descr * bd)1190 static void verify_bbt_descr(struct nand_chip *this, struct nand_bbt_descr *bd)
1191 {
1192 	u64 targetsize = nanddev_target_size(&this->base);
1193 	struct mtd_info *mtd = nand_to_mtd(this);
1194 	u32 pattern_len;
1195 	u32 bits;
1196 	u32 table_size;
1197 
1198 	if (!bd)
1199 		return;
1200 
1201 	pattern_len = bd->len;
1202 	bits = bd->options & NAND_BBT_NRBITS_MSK;
1203 
1204 	BUG_ON((this->bbt_options & NAND_BBT_NO_OOB) &&
1205 			!(this->bbt_options & NAND_BBT_USE_FLASH));
1206 	BUG_ON(!bits);
1207 
1208 	if (bd->options & NAND_BBT_VERSION)
1209 		pattern_len++;
1210 
1211 	if (bd->options & NAND_BBT_NO_OOB) {
1212 		BUG_ON(!(this->bbt_options & NAND_BBT_USE_FLASH));
1213 		BUG_ON(!(this->bbt_options & NAND_BBT_NO_OOB));
1214 		BUG_ON(bd->offs);
1215 		if (bd->options & NAND_BBT_VERSION)
1216 			BUG_ON(bd->veroffs != bd->len);
1217 		BUG_ON(bd->options & NAND_BBT_SAVECONTENT);
1218 	}
1219 
1220 	if (bd->options & NAND_BBT_PERCHIP)
1221 		table_size = targetsize >> this->bbt_erase_shift;
1222 	else
1223 		table_size = mtd->size >> this->bbt_erase_shift;
1224 	table_size >>= 3;
1225 	table_size *= bits;
1226 	if (bd->options & NAND_BBT_NO_OOB)
1227 		table_size += pattern_len;
1228 	BUG_ON(table_size > (1 << this->bbt_erase_shift));
1229 }
1230 
1231 /**
1232  * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1233  * @this: the NAND device
1234  * @bd: descriptor for the good/bad block search pattern
1235  *
1236  * The function checks, if a bad block table(s) is/are already available. If
1237  * not it scans the device for manufacturer marked good / bad blocks and writes
1238  * the bad block table(s) to the selected place.
1239  *
1240  * The bad block table memory is allocated here. It must be freed by calling
1241  * the nand_free_bbt function.
1242  */
nand_scan_bbt(struct nand_chip * this,struct nand_bbt_descr * bd)1243 static int nand_scan_bbt(struct nand_chip *this, struct nand_bbt_descr *bd)
1244 {
1245 	struct mtd_info *mtd = nand_to_mtd(this);
1246 	int len, res;
1247 	uint8_t *buf;
1248 	struct nand_bbt_descr *td = this->bbt_td;
1249 	struct nand_bbt_descr *md = this->bbt_md;
1250 
1251 	len = (mtd->size >> (this->bbt_erase_shift + 2)) ? : 1;
1252 	/*
1253 	 * Allocate memory (2bit per block) and clear the memory bad block
1254 	 * table.
1255 	 */
1256 	this->bbt = kzalloc(len, GFP_KERNEL);
1257 	if (!this->bbt)
1258 		return -ENOMEM;
1259 
1260 	/*
1261 	 * If no primary table descriptor is given, scan the device to build a
1262 	 * memory based bad block table.
1263 	 */
1264 	if (!td) {
1265 		if ((res = nand_memory_bbt(this, bd))) {
1266 			pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
1267 			goto err_free_bbt;
1268 		}
1269 		return 0;
1270 	}
1271 	verify_bbt_descr(this, td);
1272 	verify_bbt_descr(this, md);
1273 
1274 	/* Allocate a temporary buffer for one eraseblock incl. oob */
1275 	len = (1 << this->bbt_erase_shift);
1276 	len += (len >> this->page_shift) * mtd->oobsize;
1277 	buf = vmalloc(len);
1278 	if (!buf) {
1279 		res = -ENOMEM;
1280 		goto err_free_bbt;
1281 	}
1282 
1283 	/* Is the bbt at a given page? */
1284 	if (td->options & NAND_BBT_ABSPAGE) {
1285 		read_abs_bbts(this, buf, td, md);
1286 	} else {
1287 		/* Search the bad block table using a pattern in oob */
1288 		search_read_bbts(this, buf, td, md);
1289 	}
1290 
1291 	res = check_create(this, buf, bd);
1292 	if (res)
1293 		goto err_free_buf;
1294 
1295 	/* Prevent the bbt regions from erasing / writing */
1296 	mark_bbt_region(this, td);
1297 	if (md)
1298 		mark_bbt_region(this, md);
1299 
1300 	vfree(buf);
1301 	return 0;
1302 
1303 err_free_buf:
1304 	vfree(buf);
1305 err_free_bbt:
1306 	kfree(this->bbt);
1307 	this->bbt = NULL;
1308 	return res;
1309 }
1310 
1311 /*
1312  * Define some generic bad / good block scan pattern which are used
1313  * while scanning a device for factory marked good / bad blocks.
1314  */
1315 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
1316 
1317 /* Generic flash bbt descriptors */
1318 static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
1319 static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
1320 
1321 static struct nand_bbt_descr bbt_main_descr = {
1322 	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1323 		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1324 	.offs =	8,
1325 	.len = 4,
1326 	.veroffs = 12,
1327 	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1328 	.pattern = bbt_pattern
1329 };
1330 
1331 static struct nand_bbt_descr bbt_mirror_descr = {
1332 	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1333 		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
1334 	.offs =	8,
1335 	.len = 4,
1336 	.veroffs = 12,
1337 	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1338 	.pattern = mirror_pattern
1339 };
1340 
1341 static struct nand_bbt_descr bbt_main_no_oob_descr = {
1342 	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1343 		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1344 		| NAND_BBT_NO_OOB,
1345 	.len = 4,
1346 	.veroffs = 4,
1347 	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1348 	.pattern = bbt_pattern
1349 };
1350 
1351 static struct nand_bbt_descr bbt_mirror_no_oob_descr = {
1352 	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
1353 		| NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP
1354 		| NAND_BBT_NO_OOB,
1355 	.len = 4,
1356 	.veroffs = 4,
1357 	.maxblocks = NAND_BBT_SCAN_MAXBLOCKS,
1358 	.pattern = mirror_pattern
1359 };
1360 
1361 #define BADBLOCK_SCAN_MASK (~NAND_BBT_NO_OOB)
1362 /**
1363  * nand_create_badblock_pattern - [INTERN] Creates a BBT descriptor structure
1364  * @this: NAND chip to create descriptor for
1365  *
1366  * This function allocates and initializes a nand_bbt_descr for BBM detection
1367  * based on the properties of @this. The new descriptor is stored in
1368  * this->badblock_pattern. Thus, this->badblock_pattern should be NULL when
1369  * passed to this function.
1370  */
nand_create_badblock_pattern(struct nand_chip * this)1371 static int nand_create_badblock_pattern(struct nand_chip *this)
1372 {
1373 	struct nand_bbt_descr *bd;
1374 	if (this->badblock_pattern) {
1375 		pr_warn("Bad block pattern already allocated; not replacing\n");
1376 		return -EINVAL;
1377 	}
1378 	bd = kzalloc(sizeof(*bd), GFP_KERNEL);
1379 	if (!bd)
1380 		return -ENOMEM;
1381 	bd->options = this->bbt_options & BADBLOCK_SCAN_MASK;
1382 	bd->offs = this->badblockpos;
1383 	bd->len = (this->options & NAND_BUSWIDTH_16) ? 2 : 1;
1384 	bd->pattern = scan_ff_pattern;
1385 	bd->options |= NAND_BBT_DYNAMICSTRUCT;
1386 	this->badblock_pattern = bd;
1387 	return 0;
1388 }
1389 
1390 /**
1391  * nand_create_bbt - [NAND Interface] Select a default bad block table for the device
1392  * @this: NAND chip object
1393  *
1394  * This function selects the default bad block table support for the device and
1395  * calls the nand_scan_bbt function.
1396  */
nand_create_bbt(struct nand_chip * this)1397 int nand_create_bbt(struct nand_chip *this)
1398 {
1399 	int ret;
1400 
1401 	/* Is a flash based bad block table requested? */
1402 	if (this->bbt_options & NAND_BBT_USE_FLASH) {
1403 		/* Use the default pattern descriptors */
1404 		if (!this->bbt_td) {
1405 			if (this->bbt_options & NAND_BBT_NO_OOB) {
1406 				this->bbt_td = &bbt_main_no_oob_descr;
1407 				this->bbt_md = &bbt_mirror_no_oob_descr;
1408 			} else {
1409 				this->bbt_td = &bbt_main_descr;
1410 				this->bbt_md = &bbt_mirror_descr;
1411 			}
1412 		}
1413 	} else {
1414 		this->bbt_td = NULL;
1415 		this->bbt_md = NULL;
1416 	}
1417 
1418 	if (!this->badblock_pattern) {
1419 		ret = nand_create_badblock_pattern(this);
1420 		if (ret)
1421 			return ret;
1422 	}
1423 
1424 	return nand_scan_bbt(this, this->badblock_pattern);
1425 }
1426 EXPORT_SYMBOL(nand_create_bbt);
1427 
1428 /**
1429  * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
1430  * @this: NAND chip object
1431  * @offs: offset in the device
1432  */
nand_isreserved_bbt(struct nand_chip * this,loff_t offs)1433 int nand_isreserved_bbt(struct nand_chip *this, loff_t offs)
1434 {
1435 	int block;
1436 
1437 	block = (int)(offs >> this->bbt_erase_shift);
1438 	return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;
1439 }
1440 
1441 /**
1442  * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1443  * @this: NAND chip object
1444  * @offs: offset in the device
1445  * @allowbbt: allow access to bad block table region
1446  */
nand_isbad_bbt(struct nand_chip * this,loff_t offs,int allowbbt)1447 int nand_isbad_bbt(struct nand_chip *this, loff_t offs, int allowbbt)
1448 {
1449 	int block, res;
1450 
1451 	block = (int)(offs >> this->bbt_erase_shift);
1452 	res = bbt_get_entry(this, block);
1453 
1454 	pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",
1455 		 (unsigned int)offs, block, res);
1456 
1457 	if (mtd_check_expert_analysis_mode())
1458 		return 0;
1459 
1460 	switch (res) {
1461 	case BBT_BLOCK_GOOD:
1462 		return 0;
1463 	case BBT_BLOCK_WORN:
1464 		return 1;
1465 	case BBT_BLOCK_RESERVED:
1466 		return allowbbt ? 0 : 1;
1467 	}
1468 	return 1;
1469 }
1470 
1471 /**
1472  * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1473  * @this: NAND chip object
1474  * @offs: offset of the bad block
1475  */
nand_markbad_bbt(struct nand_chip * this,loff_t offs)1476 int nand_markbad_bbt(struct nand_chip *this, loff_t offs)
1477 {
1478 	int block, ret = 0;
1479 
1480 	block = (int)(offs >> this->bbt_erase_shift);
1481 
1482 	/* Mark bad block in memory */
1483 	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
1484 
1485 	/* Update flash-based bad block table */
1486 	if (this->bbt_options & NAND_BBT_USE_FLASH)
1487 		ret = nand_update_bbt(this, offs);
1488 
1489 	return ret;
1490 }
1491