xref: /linux/drivers/mtd/inftlmount.c (revision 2a2c74b2efcb1a0ca3fdcb5fbb96ad8de6a29177)
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 <asm/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 				instr->mtd = inftl->mbd.mtd;
212 
213 				/*
214 				 * 	Most likely this is using the
215 				 * 	undocumented qiuck mount feature.
216 				 * 	We don't support that, we will need
217 				 * 	to erase the hidden block for full
218 				 * 	compatibility.
219 				 */
220 				instr->addr = ip->Reserved0 * inftl->EraseSize;
221 				instr->len = inftl->EraseSize;
222 				mtd_erase(mtd, instr);
223 			}
224 			if ((ip->lastUnit - ip->firstUnit + 1) < ip->virtualUnits) {
225 				printk(KERN_WARNING "INFTL: Media Header "
226 					"Partition %d sanity check failed\n"
227 					"    firstUnit %d : lastUnit %d  >  "
228 					"virtualUnits %d\n", i, ip->lastUnit,
229 					ip->firstUnit, ip->Reserved0);
230 				return -1;
231 			}
232 			if (ip->Reserved1 != 0) {
233 				printk(KERN_WARNING "INFTL: Media Header "
234 					"Partition %d sanity check failed: "
235 					"Reserved1 %d != 0\n",
236 					i, ip->Reserved1);
237 				return -1;
238 			}
239 
240 			if (ip->flags & INFTL_BDTL)
241 				break;
242 		}
243 
244 		if (i >= 4) {
245 			printk(KERN_WARNING "INFTL: Media Header Partition "
246 				"sanity check failed:\n       No partition "
247 				"marked as Disk Partition\n");
248 			return -1;
249 		}
250 
251 		inftl->nb_boot_blocks = ip->firstUnit;
252 		inftl->numvunits = ip->virtualUnits;
253 		if (inftl->numvunits > (inftl->nb_blocks -
254 		    inftl->nb_boot_blocks - 2)) {
255 			printk(KERN_WARNING "INFTL: Media Header sanity check "
256 				"failed:\n        numvunits (%d) > nb_blocks "
257 				"(%d) - nb_boot_blocks(%d) - 2\n",
258 				inftl->numvunits, inftl->nb_blocks,
259 				inftl->nb_boot_blocks);
260 			return -1;
261 		}
262 
263 		inftl->mbd.size  = inftl->numvunits *
264 			(inftl->EraseSize / SECTORSIZE);
265 
266 		/*
267 		 * Block count is set to last used EUN (we won't need to keep
268 		 * any meta-data past that point).
269 		 */
270 		inftl->firstEUN = ip->firstUnit;
271 		inftl->lastEUN = ip->lastUnit;
272 		inftl->nb_blocks = ip->lastUnit + 1;
273 
274 		/* Memory alloc */
275 		inftl->PUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
276 		if (!inftl->PUtable) {
277 			printk(KERN_WARNING "INFTL: allocation of PUtable "
278 				"failed (%zd bytes)\n",
279 				inftl->nb_blocks * sizeof(u16));
280 			return -ENOMEM;
281 		}
282 
283 		inftl->VUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
284 		if (!inftl->VUtable) {
285 			kfree(inftl->PUtable);
286 			printk(KERN_WARNING "INFTL: allocation of VUtable "
287 				"failed (%zd bytes)\n",
288 				inftl->nb_blocks * sizeof(u16));
289 			return -ENOMEM;
290 		}
291 
292 		/* Mark the blocks before INFTL MediaHeader as reserved */
293 		for (i = 0; i < inftl->nb_boot_blocks; i++)
294 			inftl->PUtable[i] = BLOCK_RESERVED;
295 		/* Mark all remaining blocks as potentially containing data */
296 		for (; i < inftl->nb_blocks; i++)
297 			inftl->PUtable[i] = BLOCK_NOTEXPLORED;
298 
299 		/* Mark this boot record (NFTL MediaHeader) block as reserved */
300 		inftl->PUtable[block] = BLOCK_RESERVED;
301 
302 		/* Read Bad Erase Unit Table and modify PUtable[] accordingly */
303 		for (i = 0; i < inftl->nb_blocks; i++) {
304 			int physblock;
305 			/* If any of the physical eraseblocks are bad, don't
306 			   use the unit. */
307 			for (physblock = 0; physblock < inftl->EraseSize; physblock += inftl->mbd.mtd->erasesize) {
308 				if (mtd_block_isbad(inftl->mbd.mtd,
309 						    i * inftl->EraseSize + physblock))
310 					inftl->PUtable[i] = BLOCK_RESERVED;
311 			}
312 		}
313 
314 		inftl->MediaUnit = block;
315 		return 0;
316 	}
317 
318 	/* Not found. */
319 	return -1;
320 }
321 
322 static int memcmpb(void *a, int c, int n)
323 {
324 	int i;
325 	for (i = 0; i < n; i++) {
326 		if (c != ((unsigned char *)a)[i])
327 			return 1;
328 	}
329 	return 0;
330 }
331 
332 /*
333  * check_free_sector: check if a free sector is actually FREE,
334  *	i.e. All 0xff in data and oob area.
335  */
336 static int check_free_sectors(struct INFTLrecord *inftl, unsigned int address,
337 	int len, int check_oob)
338 {
339 	u8 buf[SECTORSIZE + inftl->mbd.mtd->oobsize];
340 	struct mtd_info *mtd = inftl->mbd.mtd;
341 	size_t retlen;
342 	int i;
343 
344 	for (i = 0; i < len; i += SECTORSIZE) {
345 		if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
346 			return -1;
347 		if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
348 			return -1;
349 
350 		if (check_oob) {
351 			if(inftl_read_oob(mtd, address, mtd->oobsize,
352 					  &retlen, &buf[SECTORSIZE]) < 0)
353 				return -1;
354 			if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
355 				return -1;
356 		}
357 		address += SECTORSIZE;
358 	}
359 
360 	return 0;
361 }
362 
363 /*
364  * INFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase
365  *		 Unit and Update INFTL metadata. Each erase operation is
366  *		 checked with check_free_sectors.
367  *
368  * Return: 0 when succeed, -1 on error.
369  *
370  * ToDo: 1. Is it necessary to check_free_sector after erasing ??
371  */
372 int INFTL_formatblock(struct INFTLrecord *inftl, int block)
373 {
374 	size_t retlen;
375 	struct inftl_unittail uci;
376 	struct erase_info *instr = &inftl->instr;
377 	struct mtd_info *mtd = inftl->mbd.mtd;
378 	int physblock;
379 
380 	pr_debug("INFTL: INFTL_formatblock(inftl=%p,block=%d)\n", inftl, block);
381 
382 	memset(instr, 0, sizeof(struct erase_info));
383 
384 	/* FIXME: Shouldn't we be setting the 'discarded' flag to zero
385 	   _first_? */
386 
387 	/* Use async erase interface, test return code */
388 	instr->mtd = inftl->mbd.mtd;
389 	instr->addr = block * inftl->EraseSize;
390 	instr->len = inftl->mbd.mtd->erasesize;
391 	/* Erase one physical eraseblock at a time, even though the NAND api
392 	   allows us to group them.  This way we if we have a failure, we can
393 	   mark only the failed block in the bbt. */
394 	for (physblock = 0; physblock < inftl->EraseSize;
395 	     physblock += instr->len, instr->addr += instr->len) {
396 		mtd_erase(inftl->mbd.mtd, instr);
397 
398 		if (instr->state == MTD_ERASE_FAILED) {
399 			printk(KERN_WARNING "INFTL: error while formatting block %d\n",
400 				block);
401 			goto fail;
402 		}
403 
404 		/*
405 		 * Check the "freeness" of Erase Unit before updating metadata.
406 		 * FixMe: is this check really necessary? Since we have check
407 		 * the return code after the erase operation.
408 		 */
409 		if (check_free_sectors(inftl, instr->addr, instr->len, 1) != 0)
410 			goto fail;
411 	}
412 
413 	uci.EraseMark = cpu_to_le16(ERASE_MARK);
414 	uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
415 	uci.Reserved[0] = 0;
416 	uci.Reserved[1] = 0;
417 	uci.Reserved[2] = 0;
418 	uci.Reserved[3] = 0;
419 	instr->addr = block * inftl->EraseSize + SECTORSIZE * 2;
420 	if (inftl_write_oob(mtd, instr->addr + 8, 8, &retlen, (char *)&uci) < 0)
421 		goto fail;
422 	return 0;
423 fail:
424 	/* could not format, update the bad block table (caller is responsible
425 	   for setting the PUtable to BLOCK_RESERVED on failure) */
426 	mtd_block_markbad(inftl->mbd.mtd, instr->addr);
427 	return -1;
428 }
429 
430 /*
431  * format_chain: Format an invalid Virtual Unit chain. It frees all the Erase
432  *	Units in a Virtual Unit Chain, i.e. all the units are disconnected.
433  *
434  *	Since the chain is invalid then we will have to erase it from its
435  *	head (normally for INFTL we go from the oldest). But if it has a
436  *	loop then there is no oldest...
437  */
438 static void format_chain(struct INFTLrecord *inftl, unsigned int first_block)
439 {
440 	unsigned int block = first_block, block1;
441 
442 	printk(KERN_WARNING "INFTL: formatting chain at block %d\n",
443 		first_block);
444 
445 	for (;;) {
446 		block1 = inftl->PUtable[block];
447 
448 		printk(KERN_WARNING "INFTL: formatting block %d\n", block);
449 		if (INFTL_formatblock(inftl, block) < 0) {
450 			/*
451 			 * Cannot format !!!! Mark it as Bad Unit,
452 			 */
453 			inftl->PUtable[block] = BLOCK_RESERVED;
454 		} else {
455 			inftl->PUtable[block] = BLOCK_FREE;
456 		}
457 
458 		/* Goto next block on the chain */
459 		block = block1;
460 
461 		if (block == BLOCK_NIL || block >= inftl->lastEUN)
462 			break;
463 	}
464 }
465 
466 void INFTL_dumptables(struct INFTLrecord *s)
467 {
468 	int i;
469 
470 	pr_debug("-------------------------------------------"
471 		"----------------------------------\n");
472 
473 	pr_debug("VUtable[%d] ->", s->nb_blocks);
474 	for (i = 0; i < s->nb_blocks; i++) {
475 		if ((i % 8) == 0)
476 			pr_debug("\n%04x: ", i);
477 		pr_debug("%04x ", s->VUtable[i]);
478 	}
479 
480 	pr_debug("\n-------------------------------------------"
481 		"----------------------------------\n");
482 
483 	pr_debug("PUtable[%d-%d=%d] ->", s->firstEUN, s->lastEUN, s->nb_blocks);
484 	for (i = 0; i <= s->lastEUN; i++) {
485 		if ((i % 8) == 0)
486 			pr_debug("\n%04x: ", i);
487 		pr_debug("%04x ", s->PUtable[i]);
488 	}
489 
490 	pr_debug("\n-------------------------------------------"
491 		"----------------------------------\n");
492 
493 	pr_debug("INFTL ->\n"
494 		"  EraseSize       = %d\n"
495 		"  h/s/c           = %d/%d/%d\n"
496 		"  numvunits       = %d\n"
497 		"  firstEUN        = %d\n"
498 		"  lastEUN         = %d\n"
499 		"  numfreeEUNs     = %d\n"
500 		"  LastFreeEUN     = %d\n"
501 		"  nb_blocks       = %d\n"
502 		"  nb_boot_blocks  = %d",
503 		s->EraseSize, s->heads, s->sectors, s->cylinders,
504 		s->numvunits, s->firstEUN, s->lastEUN, s->numfreeEUNs,
505 		s->LastFreeEUN, s->nb_blocks, s->nb_boot_blocks);
506 
507 	pr_debug("\n-------------------------------------------"
508 		"----------------------------------\n");
509 }
510 
511 void INFTL_dumpVUchains(struct INFTLrecord *s)
512 {
513 	int logical, block, i;
514 
515 	pr_debug("-------------------------------------------"
516 		"----------------------------------\n");
517 
518 	pr_debug("INFTL Virtual Unit Chains:\n");
519 	for (logical = 0; logical < s->nb_blocks; logical++) {
520 		block = s->VUtable[logical];
521 		if (block > s->nb_blocks)
522 			continue;
523 		pr_debug("  LOGICAL %d --> %d ", logical, block);
524 		for (i = 0; i < s->nb_blocks; i++) {
525 			if (s->PUtable[block] == BLOCK_NIL)
526 				break;
527 			block = s->PUtable[block];
528 			pr_debug("%d ", block);
529 		}
530 		pr_debug("\n");
531 	}
532 
533 	pr_debug("-------------------------------------------"
534 		"----------------------------------\n");
535 }
536 
537 int INFTL_mount(struct INFTLrecord *s)
538 {
539 	struct mtd_info *mtd = s->mbd.mtd;
540 	unsigned int block, first_block, prev_block, last_block;
541 	unsigned int first_logical_block, logical_block, erase_mark;
542 	int chain_length, do_format_chain;
543 	struct inftl_unithead1 h0;
544 	struct inftl_unittail h1;
545 	size_t retlen;
546 	int i;
547 	u8 *ANACtable, ANAC;
548 
549 	pr_debug("INFTL: INFTL_mount(inftl=%p)\n", s);
550 
551 	/* Search for INFTL MediaHeader and Spare INFTL Media Header */
552 	if (find_boot_record(s) < 0) {
553 		printk(KERN_WARNING "INFTL: could not find valid boot record?\n");
554 		return -ENXIO;
555 	}
556 
557 	/* Init the logical to physical table */
558 	for (i = 0; i < s->nb_blocks; i++)
559 		s->VUtable[i] = BLOCK_NIL;
560 
561 	logical_block = block = BLOCK_NIL;
562 
563 	/* Temporary buffer to store ANAC numbers. */
564 	ANACtable = kcalloc(s->nb_blocks, sizeof(u8), GFP_KERNEL);
565 	if (!ANACtable) {
566 		printk(KERN_WARNING "INFTL: allocation of ANACtable "
567 				"failed (%zd bytes)\n",
568 				s->nb_blocks * sizeof(u8));
569 		return -ENOMEM;
570 	}
571 
572 	/*
573 	 * First pass is to explore each physical unit, and construct the
574 	 * virtual chains that exist (newest physical unit goes into VUtable).
575 	 * Any block that is in any way invalid will be left in the
576 	 * NOTEXPLORED state. Then at the end we will try to format it and
577 	 * mark it as free.
578 	 */
579 	pr_debug("INFTL: pass 1, explore each unit\n");
580 	for (first_block = s->firstEUN; first_block <= s->lastEUN; first_block++) {
581 		if (s->PUtable[first_block] != BLOCK_NOTEXPLORED)
582 			continue;
583 
584 		do_format_chain = 0;
585 		first_logical_block = BLOCK_NIL;
586 		last_block = BLOCK_NIL;
587 		block = first_block;
588 
589 		for (chain_length = 0; ; chain_length++) {
590 
591 			if ((chain_length == 0) &&
592 			    (s->PUtable[block] != BLOCK_NOTEXPLORED)) {
593 				/* Nothing to do here, onto next block */
594 				break;
595 			}
596 
597 			if (inftl_read_oob(mtd, block * s->EraseSize + 8,
598 					   8, &retlen, (char *)&h0) < 0 ||
599 			    inftl_read_oob(mtd, block * s->EraseSize +
600 					   2 * SECTORSIZE + 8, 8, &retlen,
601 					   (char *)&h1) < 0) {
602 				/* Should never happen? */
603 				do_format_chain++;
604 				break;
605 			}
606 
607 			logical_block = le16_to_cpu(h0.virtualUnitNo);
608 			prev_block = le16_to_cpu(h0.prevUnitNo);
609 			erase_mark = le16_to_cpu((h1.EraseMark | h1.EraseMark1));
610 			ANACtable[block] = h0.ANAC;
611 
612 			/* Previous block is relative to start of Partition */
613 			if (prev_block < s->nb_blocks)
614 				prev_block += s->firstEUN;
615 
616 			/* Already explored partial chain? */
617 			if (s->PUtable[block] != BLOCK_NOTEXPLORED) {
618 				/* Check if chain for this logical */
619 				if (logical_block == first_logical_block) {
620 					if (last_block != BLOCK_NIL)
621 						s->PUtable[last_block] = block;
622 				}
623 				break;
624 			}
625 
626 			/* Check for invalid block */
627 			if (erase_mark != ERASE_MARK) {
628 				printk(KERN_WARNING "INFTL: corrupt block %d "
629 					"in chain %d, chain length %d, erase "
630 					"mark 0x%x?\n", block, first_block,
631 					chain_length, erase_mark);
632 				/*
633 				 * Assume end of chain, probably incomplete
634 				 * fold/erase...
635 				 */
636 				if (chain_length == 0)
637 					do_format_chain++;
638 				break;
639 			}
640 
641 			/* Check for it being free already then... */
642 			if ((logical_block == BLOCK_FREE) ||
643 			    (logical_block == BLOCK_NIL)) {
644 				s->PUtable[block] = BLOCK_FREE;
645 				break;
646 			}
647 
648 			/* Sanity checks on block numbers */
649 			if ((logical_block >= s->nb_blocks) ||
650 			    ((prev_block >= s->nb_blocks) &&
651 			     (prev_block != BLOCK_NIL))) {
652 				if (chain_length > 0) {
653 					printk(KERN_WARNING "INFTL: corrupt "
654 						"block %d in chain %d?\n",
655 						block, first_block);
656 					do_format_chain++;
657 				}
658 				break;
659 			}
660 
661 			if (first_logical_block == BLOCK_NIL) {
662 				first_logical_block = logical_block;
663 			} else {
664 				if (first_logical_block != logical_block) {
665 					/* Normal for folded chain... */
666 					break;
667 				}
668 			}
669 
670 			/*
671 			 * Current block is valid, so if we followed a virtual
672 			 * chain to get here then we can set the previous
673 			 * block pointer in our PUtable now. Then move onto
674 			 * the previous block in the chain.
675 			 */
676 			s->PUtable[block] = BLOCK_NIL;
677 			if (last_block != BLOCK_NIL)
678 				s->PUtable[last_block] = block;
679 			last_block = block;
680 			block = prev_block;
681 
682 			/* Check for end of chain */
683 			if (block == BLOCK_NIL)
684 				break;
685 
686 			/* Validate next block before following it... */
687 			if (block > s->lastEUN) {
688 				printk(KERN_WARNING "INFTL: invalid previous "
689 					"block %d in chain %d?\n", block,
690 					first_block);
691 				do_format_chain++;
692 				break;
693 			}
694 		}
695 
696 		if (do_format_chain) {
697 			format_chain(s, first_block);
698 			continue;
699 		}
700 
701 		/*
702 		 * Looks like a valid chain then. It may not really be the
703 		 * newest block in the chain, but it is the newest we have
704 		 * found so far. We might update it in later iterations of
705 		 * this loop if we find something newer.
706 		 */
707 		s->VUtable[first_logical_block] = first_block;
708 		logical_block = BLOCK_NIL;
709 	}
710 
711 	INFTL_dumptables(s);
712 
713 	/*
714 	 * Second pass, check for infinite loops in chains. These are
715 	 * possible because we don't update the previous pointers when
716 	 * we fold chains. No big deal, just fix them up in PUtable.
717 	 */
718 	pr_debug("INFTL: pass 2, validate virtual chains\n");
719 	for (logical_block = 0; logical_block < s->numvunits; logical_block++) {
720 		block = s->VUtable[logical_block];
721 		last_block = BLOCK_NIL;
722 
723 		/* Check for free/reserved/nil */
724 		if (block >= BLOCK_RESERVED)
725 			continue;
726 
727 		ANAC = ANACtable[block];
728 		for (i = 0; i < s->numvunits; i++) {
729 			if (s->PUtable[block] == BLOCK_NIL)
730 				break;
731 			if (s->PUtable[block] > s->lastEUN) {
732 				printk(KERN_WARNING "INFTL: invalid prev %d, "
733 					"in virtual chain %d\n",
734 					s->PUtable[block], logical_block);
735 				s->PUtable[block] = BLOCK_NIL;
736 
737 			}
738 			if (ANACtable[block] != ANAC) {
739 				/*
740 				 * Chain must point back to itself. This is ok,
741 				 * but we will need adjust the tables with this
742 				 * newest block and oldest block.
743 				 */
744 				s->VUtable[logical_block] = block;
745 				s->PUtable[last_block] = BLOCK_NIL;
746 				break;
747 			}
748 
749 			ANAC--;
750 			last_block = block;
751 			block = s->PUtable[block];
752 		}
753 
754 		if (i >= s->nb_blocks) {
755 			/*
756 			 * Uhoo, infinite chain with valid ANACS!
757 			 * Format whole chain...
758 			 */
759 			format_chain(s, first_block);
760 		}
761 	}
762 
763 	INFTL_dumptables(s);
764 	INFTL_dumpVUchains(s);
765 
766 	/*
767 	 * Third pass, format unreferenced blocks and init free block count.
768 	 */
769 	s->numfreeEUNs = 0;
770 	s->LastFreeEUN = BLOCK_NIL;
771 
772 	pr_debug("INFTL: pass 3, format unused blocks\n");
773 	for (block = s->firstEUN; block <= s->lastEUN; block++) {
774 		if (s->PUtable[block] == BLOCK_NOTEXPLORED) {
775 			printk("INFTL: unreferenced block %d, formatting it\n",
776 				block);
777 			if (INFTL_formatblock(s, block) < 0)
778 				s->PUtable[block] = BLOCK_RESERVED;
779 			else
780 				s->PUtable[block] = BLOCK_FREE;
781 		}
782 		if (s->PUtable[block] == BLOCK_FREE) {
783 			s->numfreeEUNs++;
784 			if (s->LastFreeEUN == BLOCK_NIL)
785 				s->LastFreeEUN = block;
786 		}
787 	}
788 
789 	kfree(ANACtable);
790 	return 0;
791 }
792