xref: /linux/drivers/mtd/inftlmount.c (revision 801f5e1ac783df9fafff8899ef2d5511bd4dbdcb)
1 /*
2  * inftlmount.c -- INFTL mount code with extensive checks.
3  *
4  * Author: Greg Ungerer (gerg@snapgear.com)
5  * Copyright © 2002-2003, Greg Ungerer (gerg@snapgear.com)
6  *
7  * Based heavily on the nftlmount.c code which is:
8  * Author: Fabrice Bellard (fabrice.bellard@netgem.com)
9  * Copyright © 2000 Netgem S.A.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
24  */
25 
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <asm/errno.h>
29 #include <asm/io.h>
30 #include <linux/uaccess.h>
31 #include <linux/delay.h>
32 #include <linux/slab.h>
33 #include <linux/mtd/mtd.h>
34 #include <linux/mtd/nftl.h>
35 #include <linux/mtd/inftl.h>
36 
37 /*
38  * find_boot_record: Find the INFTL Media Header and its Spare copy which
39  *	contains the various device information of the INFTL partition and
40  *	Bad Unit Table. Update the PUtable[] table according to the Bad
41  *	Unit Table. PUtable[] is used for management of Erase Unit in
42  *	other routines in inftlcore.c and inftlmount.c.
43  */
44 static int find_boot_record(struct INFTLrecord *inftl)
45 {
46 	struct inftl_unittail h1;
47 	//struct inftl_oob oob;
48 	unsigned int i, block;
49 	u8 buf[SECTORSIZE];
50 	struct INFTLMediaHeader *mh = &inftl->MediaHdr;
51 	struct mtd_info *mtd = inftl->mbd.mtd;
52 	struct INFTLPartition *ip;
53 	size_t retlen;
54 
55 	pr_debug("INFTL: find_boot_record(inftl=%p)\n", inftl);
56 
57         /*
58 	 * Assume logical EraseSize == physical erasesize for starting the
59 	 * scan. We'll sort it out later if we find a MediaHeader which says
60 	 * otherwise.
61 	 */
62 	inftl->EraseSize = inftl->mbd.mtd->erasesize;
63         inftl->nb_blocks = (u32)inftl->mbd.mtd->size / inftl->EraseSize;
64 
65 	inftl->MediaUnit = BLOCK_NIL;
66 
67 	/* Search for a valid boot record */
68 	for (block = 0; block < inftl->nb_blocks; block++) {
69 		int ret;
70 
71 		/*
72 		 * Check for BNAND header first. Then whinge if it's found
73 		 * but later checks fail.
74 		 */
75 		ret = mtd_read(mtd, block * inftl->EraseSize, SECTORSIZE,
76 			       &retlen, buf);
77 		/* We ignore ret in case the ECC of the MediaHeader is invalid
78 		   (which is apparently acceptable) */
79 		if (retlen != SECTORSIZE) {
80 			static int warncount = 5;
81 
82 			if (warncount) {
83 				printk(KERN_WARNING "INFTL: block read at 0x%x "
84 					"of mtd%d failed: %d\n",
85 					block * inftl->EraseSize,
86 					inftl->mbd.mtd->index, ret);
87 				if (!--warncount)
88 					printk(KERN_WARNING "INFTL: further "
89 						"failures for this block will "
90 						"not be printed\n");
91 			}
92 			continue;
93 		}
94 
95 		if (retlen < 6 || memcmp(buf, "BNAND", 6)) {
96 			/* BNAND\0 not found. Continue */
97 			continue;
98 		}
99 
100 		/* To be safer with BIOS, also use erase mark as discriminant */
101 		ret = inftl_read_oob(mtd,
102 				     block * inftl->EraseSize + SECTORSIZE + 8,
103 				     8, &retlen,(char *)&h1);
104 		if (ret < 0) {
105 			printk(KERN_WARNING "INFTL: ANAND header found at "
106 				"0x%x in mtd%d, but OOB data read failed "
107 				"(err %d)\n", block * inftl->EraseSize,
108 				inftl->mbd.mtd->index, ret);
109 			continue;
110 		}
111 
112 
113 		/*
114 		 * This is the first we've seen.
115 		 * Copy the media header structure into place.
116 		 */
117 		memcpy(mh, buf, sizeof(struct INFTLMediaHeader));
118 
119 		/* Read the spare media header at offset 4096 */
120 		mtd_read(mtd, block * inftl->EraseSize + 4096, SECTORSIZE,
121 			 &retlen, buf);
122 		if (retlen != SECTORSIZE) {
123 			printk(KERN_WARNING "INFTL: Unable to read spare "
124 			       "Media Header\n");
125 			return -1;
126 		}
127 		/* Check if this one is the same as the first one we found. */
128 		if (memcmp(mh, buf, sizeof(struct INFTLMediaHeader))) {
129 			printk(KERN_WARNING "INFTL: Primary and spare Media "
130 			       "Headers disagree.\n");
131 			return -1;
132 		}
133 
134 		mh->NoOfBootImageBlocks = le32_to_cpu(mh->NoOfBootImageBlocks);
135 		mh->NoOfBinaryPartitions = le32_to_cpu(mh->NoOfBinaryPartitions);
136 		mh->NoOfBDTLPartitions = le32_to_cpu(mh->NoOfBDTLPartitions);
137 		mh->BlockMultiplierBits = le32_to_cpu(mh->BlockMultiplierBits);
138 		mh->FormatFlags = le32_to_cpu(mh->FormatFlags);
139 		mh->PercentUsed = le32_to_cpu(mh->PercentUsed);
140 
141 		pr_debug("INFTL: Media Header ->\n"
142 			 "    bootRecordID          = %s\n"
143 			 "    NoOfBootImageBlocks   = %d\n"
144 			 "    NoOfBinaryPartitions  = %d\n"
145 			 "    NoOfBDTLPartitions    = %d\n"
146 			 "    BlockMultiplerBits    = %d\n"
147 			 "    FormatFlgs            = %d\n"
148 			 "    OsakVersion           = 0x%x\n"
149 			 "    PercentUsed           = %d\n",
150 			 mh->bootRecordID, mh->NoOfBootImageBlocks,
151 			 mh->NoOfBinaryPartitions,
152 			 mh->NoOfBDTLPartitions,
153 			 mh->BlockMultiplierBits, mh->FormatFlags,
154 			 mh->OsakVersion, mh->PercentUsed);
155 
156 		if (mh->NoOfBDTLPartitions == 0) {
157 			printk(KERN_WARNING "INFTL: Media Header sanity check "
158 				"failed: NoOfBDTLPartitions (%d) == 0, "
159 				"must be at least 1\n", mh->NoOfBDTLPartitions);
160 			return -1;
161 		}
162 
163 		if ((mh->NoOfBDTLPartitions + mh->NoOfBinaryPartitions) > 4) {
164 			printk(KERN_WARNING "INFTL: Media Header sanity check "
165 				"failed: Total Partitions (%d) > 4, "
166 				"BDTL=%d Binary=%d\n", mh->NoOfBDTLPartitions +
167 				mh->NoOfBinaryPartitions,
168 				mh->NoOfBDTLPartitions,
169 				mh->NoOfBinaryPartitions);
170 			return -1;
171 		}
172 
173 		if (mh->BlockMultiplierBits > 1) {
174 			printk(KERN_WARNING "INFTL: sorry, we don't support "
175 				"UnitSizeFactor 0x%02x\n",
176 				mh->BlockMultiplierBits);
177 			return -1;
178 		} else if (mh->BlockMultiplierBits == 1) {
179 			printk(KERN_WARNING "INFTL: support for INFTL with "
180 				"UnitSizeFactor 0x%02x is experimental\n",
181 				mh->BlockMultiplierBits);
182 			inftl->EraseSize = inftl->mbd.mtd->erasesize <<
183 				mh->BlockMultiplierBits;
184 			inftl->nb_blocks = (u32)inftl->mbd.mtd->size / inftl->EraseSize;
185 			block >>= mh->BlockMultiplierBits;
186 		}
187 
188 		/* Scan the partitions */
189 		for (i = 0; (i < 4); i++) {
190 			ip = &mh->Partitions[i];
191 			ip->virtualUnits = le32_to_cpu(ip->virtualUnits);
192 			ip->firstUnit = le32_to_cpu(ip->firstUnit);
193 			ip->lastUnit = le32_to_cpu(ip->lastUnit);
194 			ip->flags = le32_to_cpu(ip->flags);
195 			ip->spareUnits = le32_to_cpu(ip->spareUnits);
196 			ip->Reserved0 = le32_to_cpu(ip->Reserved0);
197 
198 			pr_debug("    PARTITION[%d] ->\n"
199 				 "        virtualUnits    = %d\n"
200 				 "        firstUnit       = %d\n"
201 				 "        lastUnit        = %d\n"
202 				 "        flags           = 0x%x\n"
203 				 "        spareUnits      = %d\n",
204 				 i, ip->virtualUnits, ip->firstUnit,
205 				 ip->lastUnit, ip->flags,
206 				 ip->spareUnits);
207 
208 			if (ip->Reserved0 != ip->firstUnit) {
209 				struct erase_info *instr = &inftl->instr;
210 
211 				/*
212 				 * 	Most likely this is using the
213 				 * 	undocumented qiuck mount feature.
214 				 * 	We don't support that, we will need
215 				 * 	to erase the hidden block for full
216 				 * 	compatibility.
217 				 */
218 				instr->addr = ip->Reserved0 * inftl->EraseSize;
219 				instr->len = inftl->EraseSize;
220 				mtd_erase(mtd, instr);
221 			}
222 			if ((ip->lastUnit - ip->firstUnit + 1) < ip->virtualUnits) {
223 				printk(KERN_WARNING "INFTL: Media Header "
224 					"Partition %d sanity check failed\n"
225 					"    firstUnit %d : lastUnit %d  >  "
226 					"virtualUnits %d\n", i, ip->lastUnit,
227 					ip->firstUnit, ip->Reserved0);
228 				return -1;
229 			}
230 			if (ip->Reserved1 != 0) {
231 				printk(KERN_WARNING "INFTL: Media Header "
232 					"Partition %d sanity check failed: "
233 					"Reserved1 %d != 0\n",
234 					i, ip->Reserved1);
235 				return -1;
236 			}
237 
238 			if (ip->flags & INFTL_BDTL)
239 				break;
240 		}
241 
242 		if (i >= 4) {
243 			printk(KERN_WARNING "INFTL: Media Header Partition "
244 				"sanity check failed:\n       No partition "
245 				"marked as Disk Partition\n");
246 			return -1;
247 		}
248 
249 		inftl->nb_boot_blocks = ip->firstUnit;
250 		inftl->numvunits = ip->virtualUnits;
251 		if (inftl->numvunits > (inftl->nb_blocks -
252 		    inftl->nb_boot_blocks - 2)) {
253 			printk(KERN_WARNING "INFTL: Media Header sanity check "
254 				"failed:\n        numvunits (%d) > nb_blocks "
255 				"(%d) - nb_boot_blocks(%d) - 2\n",
256 				inftl->numvunits, inftl->nb_blocks,
257 				inftl->nb_boot_blocks);
258 			return -1;
259 		}
260 
261 		inftl->mbd.size  = inftl->numvunits *
262 			(inftl->EraseSize / SECTORSIZE);
263 
264 		/*
265 		 * Block count is set to last used EUN (we won't need to keep
266 		 * any meta-data past that point).
267 		 */
268 		inftl->firstEUN = ip->firstUnit;
269 		inftl->lastEUN = ip->lastUnit;
270 		inftl->nb_blocks = ip->lastUnit + 1;
271 
272 		/* Memory alloc */
273 		inftl->PUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
274 		if (!inftl->PUtable) {
275 			printk(KERN_WARNING "INFTL: allocation of PUtable "
276 				"failed (%zd bytes)\n",
277 				inftl->nb_blocks * sizeof(u16));
278 			return -ENOMEM;
279 		}
280 
281 		inftl->VUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
282 		if (!inftl->VUtable) {
283 			kfree(inftl->PUtable);
284 			printk(KERN_WARNING "INFTL: allocation of VUtable "
285 				"failed (%zd bytes)\n",
286 				inftl->nb_blocks * sizeof(u16));
287 			return -ENOMEM;
288 		}
289 
290 		/* Mark the blocks before INFTL MediaHeader as reserved */
291 		for (i = 0; i < inftl->nb_boot_blocks; i++)
292 			inftl->PUtable[i] = BLOCK_RESERVED;
293 		/* Mark all remaining blocks as potentially containing data */
294 		for (; i < inftl->nb_blocks; i++)
295 			inftl->PUtable[i] = BLOCK_NOTEXPLORED;
296 
297 		/* Mark this boot record (NFTL MediaHeader) block as reserved */
298 		inftl->PUtable[block] = BLOCK_RESERVED;
299 
300 		/* Read Bad Erase Unit Table and modify PUtable[] accordingly */
301 		for (i = 0; i < inftl->nb_blocks; i++) {
302 			int physblock;
303 			/* If any of the physical eraseblocks are bad, don't
304 			   use the unit. */
305 			for (physblock = 0; physblock < inftl->EraseSize; physblock += inftl->mbd.mtd->erasesize) {
306 				if (mtd_block_isbad(inftl->mbd.mtd,
307 						    i * inftl->EraseSize + physblock))
308 					inftl->PUtable[i] = BLOCK_RESERVED;
309 			}
310 		}
311 
312 		inftl->MediaUnit = block;
313 		return 0;
314 	}
315 
316 	/* Not found. */
317 	return -1;
318 }
319 
320 static int memcmpb(void *a, int c, int n)
321 {
322 	int i;
323 	for (i = 0; i < n; i++) {
324 		if (c != ((unsigned char *)a)[i])
325 			return 1;
326 	}
327 	return 0;
328 }
329 
330 /*
331  * check_free_sector: check if a free sector is actually FREE,
332  *	i.e. All 0xff in data and oob area.
333  */
334 static int check_free_sectors(struct INFTLrecord *inftl, unsigned int address,
335 	int len, int check_oob)
336 {
337 	struct mtd_info *mtd = inftl->mbd.mtd;
338 	size_t retlen;
339 	int i, ret;
340 	u8 *buf;
341 
342 	buf = kmalloc(SECTORSIZE + mtd->oobsize, GFP_KERNEL);
343 	if (!buf)
344 		return -1;
345 
346 	ret = -1;
347 	for (i = 0; i < len; i += SECTORSIZE) {
348 		if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
349 			goto out;
350 		if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
351 			goto out;
352 
353 		if (check_oob) {
354 			if(inftl_read_oob(mtd, address, mtd->oobsize,
355 					  &retlen, &buf[SECTORSIZE]) < 0)
356 				goto out;
357 			if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
358 				goto out;
359 		}
360 		address += SECTORSIZE;
361 	}
362 
363 	ret = 0;
364 
365 out:
366 	kfree(buf);
367 	return ret;
368 }
369 
370 /*
371  * INFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase
372  *		 Unit and Update INFTL metadata. Each erase operation is
373  *		 checked with check_free_sectors.
374  *
375  * Return: 0 when succeed, -1 on error.
376  *
377  * ToDo: 1. Is it necessary to check_free_sector after erasing ??
378  */
379 int INFTL_formatblock(struct INFTLrecord *inftl, int block)
380 {
381 	size_t retlen;
382 	struct inftl_unittail uci;
383 	struct erase_info *instr = &inftl->instr;
384 	struct mtd_info *mtd = inftl->mbd.mtd;
385 	int physblock;
386 
387 	pr_debug("INFTL: INFTL_formatblock(inftl=%p,block=%d)\n", inftl, block);
388 
389 	memset(instr, 0, sizeof(struct erase_info));
390 
391 	/* FIXME: Shouldn't we be setting the 'discarded' flag to zero
392 	   _first_? */
393 
394 	/* Use async erase interface, test return code */
395 	instr->addr = block * inftl->EraseSize;
396 	instr->len = inftl->mbd.mtd->erasesize;
397 	/* Erase one physical eraseblock at a time, even though the NAND api
398 	   allows us to group them.  This way we if we have a failure, we can
399 	   mark only the failed block in the bbt. */
400 	for (physblock = 0; physblock < inftl->EraseSize;
401 	     physblock += instr->len, instr->addr += instr->len) {
402 		int ret;
403 
404 		ret = mtd_erase(inftl->mbd.mtd, instr);
405 		if (ret) {
406 			printk(KERN_WARNING "INFTL: error while formatting block %d\n",
407 				block);
408 			goto fail;
409 		}
410 
411 		/*
412 		 * Check the "freeness" of Erase Unit before updating metadata.
413 		 * FixMe: is this check really necessary? Since we have check
414 		 * the return code after the erase operation.
415 		 */
416 		if (check_free_sectors(inftl, instr->addr, instr->len, 1) != 0)
417 			goto fail;
418 	}
419 
420 	uci.EraseMark = cpu_to_le16(ERASE_MARK);
421 	uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
422 	uci.Reserved[0] = 0;
423 	uci.Reserved[1] = 0;
424 	uci.Reserved[2] = 0;
425 	uci.Reserved[3] = 0;
426 	instr->addr = block * inftl->EraseSize + SECTORSIZE * 2;
427 	if (inftl_write_oob(mtd, instr->addr + 8, 8, &retlen, (char *)&uci) < 0)
428 		goto fail;
429 	return 0;
430 fail:
431 	/* could not format, update the bad block table (caller is responsible
432 	   for setting the PUtable to BLOCK_RESERVED on failure) */
433 	mtd_block_markbad(inftl->mbd.mtd, instr->addr);
434 	return -1;
435 }
436 
437 /*
438  * format_chain: Format an invalid Virtual Unit chain. It frees all the Erase
439  *	Units in a Virtual Unit Chain, i.e. all the units are disconnected.
440  *
441  *	Since the chain is invalid then we will have to erase it from its
442  *	head (normally for INFTL we go from the oldest). But if it has a
443  *	loop then there is no oldest...
444  */
445 static void format_chain(struct INFTLrecord *inftl, unsigned int first_block)
446 {
447 	unsigned int block = first_block, block1;
448 
449 	printk(KERN_WARNING "INFTL: formatting chain at block %d\n",
450 		first_block);
451 
452 	for (;;) {
453 		block1 = inftl->PUtable[block];
454 
455 		printk(KERN_WARNING "INFTL: formatting block %d\n", block);
456 		if (INFTL_formatblock(inftl, block) < 0) {
457 			/*
458 			 * Cannot format !!!! Mark it as Bad Unit,
459 			 */
460 			inftl->PUtable[block] = BLOCK_RESERVED;
461 		} else {
462 			inftl->PUtable[block] = BLOCK_FREE;
463 		}
464 
465 		/* Goto next block on the chain */
466 		block = block1;
467 
468 		if (block == BLOCK_NIL || block >= inftl->lastEUN)
469 			break;
470 	}
471 }
472 
473 void INFTL_dumptables(struct INFTLrecord *s)
474 {
475 	int i;
476 
477 	pr_debug("-------------------------------------------"
478 		"----------------------------------\n");
479 
480 	pr_debug("VUtable[%d] ->", s->nb_blocks);
481 	for (i = 0; i < s->nb_blocks; i++) {
482 		if ((i % 8) == 0)
483 			pr_debug("\n%04x: ", i);
484 		pr_debug("%04x ", s->VUtable[i]);
485 	}
486 
487 	pr_debug("\n-------------------------------------------"
488 		"----------------------------------\n");
489 
490 	pr_debug("PUtable[%d-%d=%d] ->", s->firstEUN, s->lastEUN, s->nb_blocks);
491 	for (i = 0; i <= s->lastEUN; i++) {
492 		if ((i % 8) == 0)
493 			pr_debug("\n%04x: ", i);
494 		pr_debug("%04x ", s->PUtable[i]);
495 	}
496 
497 	pr_debug("\n-------------------------------------------"
498 		"----------------------------------\n");
499 
500 	pr_debug("INFTL ->\n"
501 		"  EraseSize       = %d\n"
502 		"  h/s/c           = %d/%d/%d\n"
503 		"  numvunits       = %d\n"
504 		"  firstEUN        = %d\n"
505 		"  lastEUN         = %d\n"
506 		"  numfreeEUNs     = %d\n"
507 		"  LastFreeEUN     = %d\n"
508 		"  nb_blocks       = %d\n"
509 		"  nb_boot_blocks  = %d",
510 		s->EraseSize, s->heads, s->sectors, s->cylinders,
511 		s->numvunits, s->firstEUN, s->lastEUN, s->numfreeEUNs,
512 		s->LastFreeEUN, s->nb_blocks, s->nb_boot_blocks);
513 
514 	pr_debug("\n-------------------------------------------"
515 		"----------------------------------\n");
516 }
517 
518 void INFTL_dumpVUchains(struct INFTLrecord *s)
519 {
520 	int logical, block, i;
521 
522 	pr_debug("-------------------------------------------"
523 		"----------------------------------\n");
524 
525 	pr_debug("INFTL Virtual Unit Chains:\n");
526 	for (logical = 0; logical < s->nb_blocks; logical++) {
527 		block = s->VUtable[logical];
528 		if (block >= s->nb_blocks)
529 			continue;
530 		pr_debug("  LOGICAL %d --> %d ", logical, block);
531 		for (i = 0; i < s->nb_blocks; i++) {
532 			if (s->PUtable[block] == BLOCK_NIL)
533 				break;
534 			block = s->PUtable[block];
535 			pr_debug("%d ", block);
536 		}
537 		pr_debug("\n");
538 	}
539 
540 	pr_debug("-------------------------------------------"
541 		"----------------------------------\n");
542 }
543 
544 int INFTL_mount(struct INFTLrecord *s)
545 {
546 	struct mtd_info *mtd = s->mbd.mtd;
547 	unsigned int block, first_block, prev_block, last_block;
548 	unsigned int first_logical_block, logical_block, erase_mark;
549 	int chain_length, do_format_chain;
550 	struct inftl_unithead1 h0;
551 	struct inftl_unittail h1;
552 	size_t retlen;
553 	int i;
554 	u8 *ANACtable, ANAC;
555 
556 	pr_debug("INFTL: INFTL_mount(inftl=%p)\n", s);
557 
558 	/* Search for INFTL MediaHeader and Spare INFTL Media Header */
559 	if (find_boot_record(s) < 0) {
560 		printk(KERN_WARNING "INFTL: could not find valid boot record?\n");
561 		return -ENXIO;
562 	}
563 
564 	/* Init the logical to physical table */
565 	for (i = 0; i < s->nb_blocks; i++)
566 		s->VUtable[i] = BLOCK_NIL;
567 
568 	logical_block = block = BLOCK_NIL;
569 
570 	/* Temporary buffer to store ANAC numbers. */
571 	ANACtable = kcalloc(s->nb_blocks, sizeof(u8), GFP_KERNEL);
572 	if (!ANACtable) {
573 		printk(KERN_WARNING "INFTL: allocation of ANACtable "
574 				"failed (%zd bytes)\n",
575 				s->nb_blocks * sizeof(u8));
576 		return -ENOMEM;
577 	}
578 
579 	/*
580 	 * First pass is to explore each physical unit, and construct the
581 	 * virtual chains that exist (newest physical unit goes into VUtable).
582 	 * Any block that is in any way invalid will be left in the
583 	 * NOTEXPLORED state. Then at the end we will try to format it and
584 	 * mark it as free.
585 	 */
586 	pr_debug("INFTL: pass 1, explore each unit\n");
587 	for (first_block = s->firstEUN; first_block <= s->lastEUN; first_block++) {
588 		if (s->PUtable[first_block] != BLOCK_NOTEXPLORED)
589 			continue;
590 
591 		do_format_chain = 0;
592 		first_logical_block = BLOCK_NIL;
593 		last_block = BLOCK_NIL;
594 		block = first_block;
595 
596 		for (chain_length = 0; ; chain_length++) {
597 
598 			if ((chain_length == 0) &&
599 			    (s->PUtable[block] != BLOCK_NOTEXPLORED)) {
600 				/* Nothing to do here, onto next block */
601 				break;
602 			}
603 
604 			if (inftl_read_oob(mtd, block * s->EraseSize + 8,
605 					   8, &retlen, (char *)&h0) < 0 ||
606 			    inftl_read_oob(mtd, block * s->EraseSize +
607 					   2 * SECTORSIZE + 8, 8, &retlen,
608 					   (char *)&h1) < 0) {
609 				/* Should never happen? */
610 				do_format_chain++;
611 				break;
612 			}
613 
614 			logical_block = le16_to_cpu(h0.virtualUnitNo);
615 			prev_block = le16_to_cpu(h0.prevUnitNo);
616 			erase_mark = le16_to_cpu((h1.EraseMark | h1.EraseMark1));
617 			ANACtable[block] = h0.ANAC;
618 
619 			/* Previous block is relative to start of Partition */
620 			if (prev_block < s->nb_blocks)
621 				prev_block += s->firstEUN;
622 
623 			/* Already explored partial chain? */
624 			if (s->PUtable[block] != BLOCK_NOTEXPLORED) {
625 				/* Check if chain for this logical */
626 				if (logical_block == first_logical_block) {
627 					if (last_block != BLOCK_NIL)
628 						s->PUtable[last_block] = block;
629 				}
630 				break;
631 			}
632 
633 			/* Check for invalid block */
634 			if (erase_mark != ERASE_MARK) {
635 				printk(KERN_WARNING "INFTL: corrupt block %d "
636 					"in chain %d, chain length %d, erase "
637 					"mark 0x%x?\n", block, first_block,
638 					chain_length, erase_mark);
639 				/*
640 				 * Assume end of chain, probably incomplete
641 				 * fold/erase...
642 				 */
643 				if (chain_length == 0)
644 					do_format_chain++;
645 				break;
646 			}
647 
648 			/* Check for it being free already then... */
649 			if ((logical_block == BLOCK_FREE) ||
650 			    (logical_block == BLOCK_NIL)) {
651 				s->PUtable[block] = BLOCK_FREE;
652 				break;
653 			}
654 
655 			/* Sanity checks on block numbers */
656 			if ((logical_block >= s->nb_blocks) ||
657 			    ((prev_block >= s->nb_blocks) &&
658 			     (prev_block != BLOCK_NIL))) {
659 				if (chain_length > 0) {
660 					printk(KERN_WARNING "INFTL: corrupt "
661 						"block %d in chain %d?\n",
662 						block, first_block);
663 					do_format_chain++;
664 				}
665 				break;
666 			}
667 
668 			if (first_logical_block == BLOCK_NIL) {
669 				first_logical_block = logical_block;
670 			} else {
671 				if (first_logical_block != logical_block) {
672 					/* Normal for folded chain... */
673 					break;
674 				}
675 			}
676 
677 			/*
678 			 * Current block is valid, so if we followed a virtual
679 			 * chain to get here then we can set the previous
680 			 * block pointer in our PUtable now. Then move onto
681 			 * the previous block in the chain.
682 			 */
683 			s->PUtable[block] = BLOCK_NIL;
684 			if (last_block != BLOCK_NIL)
685 				s->PUtable[last_block] = block;
686 			last_block = block;
687 			block = prev_block;
688 
689 			/* Check for end of chain */
690 			if (block == BLOCK_NIL)
691 				break;
692 
693 			/* Validate next block before following it... */
694 			if (block > s->lastEUN) {
695 				printk(KERN_WARNING "INFTL: invalid previous "
696 					"block %d in chain %d?\n", block,
697 					first_block);
698 				do_format_chain++;
699 				break;
700 			}
701 		}
702 
703 		if (do_format_chain) {
704 			format_chain(s, first_block);
705 			continue;
706 		}
707 
708 		/*
709 		 * Looks like a valid chain then. It may not really be the
710 		 * newest block in the chain, but it is the newest we have
711 		 * found so far. We might update it in later iterations of
712 		 * this loop if we find something newer.
713 		 */
714 		s->VUtable[first_logical_block] = first_block;
715 		logical_block = BLOCK_NIL;
716 	}
717 
718 	INFTL_dumptables(s);
719 
720 	/*
721 	 * Second pass, check for infinite loops in chains. These are
722 	 * possible because we don't update the previous pointers when
723 	 * we fold chains. No big deal, just fix them up in PUtable.
724 	 */
725 	pr_debug("INFTL: pass 2, validate virtual chains\n");
726 	for (logical_block = 0; logical_block < s->numvunits; logical_block++) {
727 		block = s->VUtable[logical_block];
728 		last_block = BLOCK_NIL;
729 
730 		/* Check for free/reserved/nil */
731 		if (block >= BLOCK_RESERVED)
732 			continue;
733 
734 		ANAC = ANACtable[block];
735 		for (i = 0; i < s->numvunits; i++) {
736 			if (s->PUtable[block] == BLOCK_NIL)
737 				break;
738 			if (s->PUtable[block] > s->lastEUN) {
739 				printk(KERN_WARNING "INFTL: invalid prev %d, "
740 					"in virtual chain %d\n",
741 					s->PUtable[block], logical_block);
742 				s->PUtable[block] = BLOCK_NIL;
743 
744 			}
745 			if (ANACtable[block] != ANAC) {
746 				/*
747 				 * Chain must point back to itself. This is ok,
748 				 * but we will need adjust the tables with this
749 				 * newest block and oldest block.
750 				 */
751 				s->VUtable[logical_block] = block;
752 				s->PUtable[last_block] = BLOCK_NIL;
753 				break;
754 			}
755 
756 			ANAC--;
757 			last_block = block;
758 			block = s->PUtable[block];
759 		}
760 
761 		if (i >= s->nb_blocks) {
762 			/*
763 			 * Uhoo, infinite chain with valid ANACS!
764 			 * Format whole chain...
765 			 */
766 			format_chain(s, first_block);
767 		}
768 	}
769 
770 	INFTL_dumptables(s);
771 	INFTL_dumpVUchains(s);
772 
773 	/*
774 	 * Third pass, format unreferenced blocks and init free block count.
775 	 */
776 	s->numfreeEUNs = 0;
777 	s->LastFreeEUN = BLOCK_NIL;
778 
779 	pr_debug("INFTL: pass 3, format unused blocks\n");
780 	for (block = s->firstEUN; block <= s->lastEUN; block++) {
781 		if (s->PUtable[block] == BLOCK_NOTEXPLORED) {
782 			printk("INFTL: unreferenced block %d, formatting it\n",
783 				block);
784 			if (INFTL_formatblock(s, block) < 0)
785 				s->PUtable[block] = BLOCK_RESERVED;
786 			else
787 				s->PUtable[block] = BLOCK_FREE;
788 		}
789 		if (s->PUtable[block] == BLOCK_FREE) {
790 			s->numfreeEUNs++;
791 			if (s->LastFreeEUN == BLOCK_NIL)
792 				s->LastFreeEUN = block;
793 		}
794 	}
795 
796 	kfree(ANACtable);
797 	return 0;
798 }
799