xref: /openbmc/linux/drivers/mtd/inftlmount.c (revision b6dcefde)
1 /*
2  * inftlmount.c -- INFTL mount code with extensive checks.
3  *
4  * Author: Greg Ungerer (gerg@snapgear.com)
5  * (C) 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 (C) 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/init.h>
34 #include <linux/mtd/mtd.h>
35 #include <linux/mtd/nftl.h>
36 #include <linux/mtd/inftl.h>
37 #include <linux/mtd/compatmac.h>
38 
39 /*
40  * find_boot_record: Find the INFTL Media Header and its Spare copy which
41  *	contains the various device information of the INFTL partition and
42  *	Bad Unit Table. Update the PUtable[] table according to the Bad
43  *	Unit Table. PUtable[] is used for management of Erase Unit in
44  *	other routines in inftlcore.c and inftlmount.c.
45  */
46 static int find_boot_record(struct INFTLrecord *inftl)
47 {
48 	struct inftl_unittail h1;
49 	//struct inftl_oob oob;
50 	unsigned int i, block;
51 	u8 buf[SECTORSIZE];
52 	struct INFTLMediaHeader *mh = &inftl->MediaHdr;
53 	struct mtd_info *mtd = inftl->mbd.mtd;
54 	struct INFTLPartition *ip;
55 	size_t retlen;
56 
57 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: find_boot_record(inftl=%p)\n", inftl);
58 
59         /*
60 	 * Assume logical EraseSize == physical erasesize for starting the
61 	 * scan. We'll sort it out later if we find a MediaHeader which says
62 	 * otherwise.
63 	 */
64 	inftl->EraseSize = inftl->mbd.mtd->erasesize;
65         inftl->nb_blocks = (u32)inftl->mbd.mtd->size / inftl->EraseSize;
66 
67 	inftl->MediaUnit = BLOCK_NIL;
68 
69 	/* Search for a valid boot record */
70 	for (block = 0; block < inftl->nb_blocks; block++) {
71 		int ret;
72 
73 		/*
74 		 * Check for BNAND header first. Then whinge if it's found
75 		 * but later checks fail.
76 		 */
77 		ret = mtd->read(mtd, block * inftl->EraseSize,
78 				SECTORSIZE, &retlen, buf);
79 		/* We ignore ret in case the ECC of the MediaHeader is invalid
80 		   (which is apparently acceptable) */
81 		if (retlen != SECTORSIZE) {
82 			static int warncount = 5;
83 
84 			if (warncount) {
85 				printk(KERN_WARNING "INFTL: block read at 0x%x "
86 					"of mtd%d failed: %d\n",
87 					block * inftl->EraseSize,
88 					inftl->mbd.mtd->index, ret);
89 				if (!--warncount)
90 					printk(KERN_WARNING "INFTL: further "
91 						"failures for this block will "
92 						"not be printed\n");
93 			}
94 			continue;
95 		}
96 
97 		if (retlen < 6 || memcmp(buf, "BNAND", 6)) {
98 			/* BNAND\0 not found. Continue */
99 			continue;
100 		}
101 
102 		/* To be safer with BIOS, also use erase mark as discriminant */
103 		if ((ret = inftl_read_oob(mtd, block * inftl->EraseSize +
104 					  SECTORSIZE + 8, 8, &retlen,
105 					  (char *)&h1) < 0)) {
106 			printk(KERN_WARNING "INFTL: ANAND header found at "
107 				"0x%x in mtd%d, but OOB data read failed "
108 				"(err %d)\n", block * inftl->EraseSize,
109 				inftl->mbd.mtd->index, ret);
110 			continue;
111 		}
112 
113 
114 		/*
115 		 * This is the first we've seen.
116 		 * Copy the media header structure into place.
117 		 */
118 		memcpy(mh, buf, sizeof(struct INFTLMediaHeader));
119 
120 		/* Read the spare media header at offset 4096 */
121 		mtd->read(mtd, block * inftl->EraseSize + 4096,
122 			  SECTORSIZE, &retlen, buf);
123 		if (retlen != SECTORSIZE) {
124 			printk(KERN_WARNING "INFTL: Unable to read spare "
125 			       "Media Header\n");
126 			return -1;
127 		}
128 		/* Check if this one is the same as the first one we found. */
129 		if (memcmp(mh, buf, sizeof(struct INFTLMediaHeader))) {
130 			printk(KERN_WARNING "INFTL: Primary and spare Media "
131 			       "Headers disagree.\n");
132 			return -1;
133 		}
134 
135 		mh->NoOfBootImageBlocks = le32_to_cpu(mh->NoOfBootImageBlocks);
136 		mh->NoOfBinaryPartitions = le32_to_cpu(mh->NoOfBinaryPartitions);
137 		mh->NoOfBDTLPartitions = le32_to_cpu(mh->NoOfBDTLPartitions);
138 		mh->BlockMultiplierBits = le32_to_cpu(mh->BlockMultiplierBits);
139 		mh->FormatFlags = le32_to_cpu(mh->FormatFlags);
140 		mh->PercentUsed = le32_to_cpu(mh->PercentUsed);
141 
142 #ifdef CONFIG_MTD_DEBUG_VERBOSE
143 		if (CONFIG_MTD_DEBUG_VERBOSE >= 2) {
144 			printk("INFTL: Media Header ->\n"
145 				"    bootRecordID          = %s\n"
146 				"    NoOfBootImageBlocks   = %d\n"
147 				"    NoOfBinaryPartitions  = %d\n"
148 				"    NoOfBDTLPartitions    = %d\n"
149 				"    BlockMultiplerBits    = %d\n"
150 				"    FormatFlgs            = %d\n"
151 				"    OsakVersion           = 0x%x\n"
152 				"    PercentUsed           = %d\n",
153 				mh->bootRecordID, mh->NoOfBootImageBlocks,
154 				mh->NoOfBinaryPartitions,
155 				mh->NoOfBDTLPartitions,
156 				mh->BlockMultiplierBits, mh->FormatFlags,
157 				mh->OsakVersion, mh->PercentUsed);
158 		}
159 #endif
160 
161 		if (mh->NoOfBDTLPartitions == 0) {
162 			printk(KERN_WARNING "INFTL: Media Header sanity check "
163 				"failed: NoOfBDTLPartitions (%d) == 0, "
164 				"must be at least 1\n", mh->NoOfBDTLPartitions);
165 			return -1;
166 		}
167 
168 		if ((mh->NoOfBDTLPartitions + mh->NoOfBinaryPartitions) > 4) {
169 			printk(KERN_WARNING "INFTL: Media Header sanity check "
170 				"failed: Total Partitions (%d) > 4, "
171 				"BDTL=%d Binary=%d\n", mh->NoOfBDTLPartitions +
172 				mh->NoOfBinaryPartitions,
173 				mh->NoOfBDTLPartitions,
174 				mh->NoOfBinaryPartitions);
175 			return -1;
176 		}
177 
178 		if (mh->BlockMultiplierBits > 1) {
179 			printk(KERN_WARNING "INFTL: sorry, we don't support "
180 				"UnitSizeFactor 0x%02x\n",
181 				mh->BlockMultiplierBits);
182 			return -1;
183 		} else if (mh->BlockMultiplierBits == 1) {
184 			printk(KERN_WARNING "INFTL: support for INFTL with "
185 				"UnitSizeFactor 0x%02x is experimental\n",
186 				mh->BlockMultiplierBits);
187 			inftl->EraseSize = inftl->mbd.mtd->erasesize <<
188 				mh->BlockMultiplierBits;
189 			inftl->nb_blocks = (u32)inftl->mbd.mtd->size / inftl->EraseSize;
190 			block >>= mh->BlockMultiplierBits;
191 		}
192 
193 		/* Scan the partitions */
194 		for (i = 0; (i < 4); i++) {
195 			ip = &mh->Partitions[i];
196 			ip->virtualUnits = le32_to_cpu(ip->virtualUnits);
197 			ip->firstUnit = le32_to_cpu(ip->firstUnit);
198 			ip->lastUnit = le32_to_cpu(ip->lastUnit);
199 			ip->flags = le32_to_cpu(ip->flags);
200 			ip->spareUnits = le32_to_cpu(ip->spareUnits);
201 			ip->Reserved0 = le32_to_cpu(ip->Reserved0);
202 
203 #ifdef CONFIG_MTD_DEBUG_VERBOSE
204 			if (CONFIG_MTD_DEBUG_VERBOSE >= 2) {
205 				printk("    PARTITION[%d] ->\n"
206 					"        virtualUnits    = %d\n"
207 					"        firstUnit       = %d\n"
208 					"        lastUnit        = %d\n"
209 					"        flags           = 0x%x\n"
210 					"        spareUnits      = %d\n",
211 					i, ip->virtualUnits, ip->firstUnit,
212 					ip->lastUnit, ip->flags,
213 					ip->spareUnits);
214 			}
215 #endif
216 
217 			if (ip->Reserved0 != ip->firstUnit) {
218 				struct erase_info *instr = &inftl->instr;
219 
220 				instr->mtd = inftl->mbd.mtd;
221 
222 				/*
223 				 * 	Most likely this is using the
224 				 * 	undocumented qiuck mount feature.
225 				 * 	We don't support that, we will need
226 				 * 	to erase the hidden block for full
227 				 * 	compatibility.
228 				 */
229 				instr->addr = ip->Reserved0 * inftl->EraseSize;
230 				instr->len = inftl->EraseSize;
231 				mtd->erase(mtd, instr);
232 			}
233 			if ((ip->lastUnit - ip->firstUnit + 1) < ip->virtualUnits) {
234 				printk(KERN_WARNING "INFTL: Media Header "
235 					"Partition %d sanity check failed\n"
236 					"    firstUnit %d : lastUnit %d  >  "
237 					"virtualUnits %d\n", i, ip->lastUnit,
238 					ip->firstUnit, ip->Reserved0);
239 				return -1;
240 			}
241 			if (ip->Reserved1 != 0) {
242 				printk(KERN_WARNING "INFTL: Media Header "
243 					"Partition %d sanity check failed: "
244 					"Reserved1 %d != 0\n",
245 					i, ip->Reserved1);
246 				return -1;
247 			}
248 
249 			if (ip->flags & INFTL_BDTL)
250 				break;
251 		}
252 
253 		if (i >= 4) {
254 			printk(KERN_WARNING "INFTL: Media Header Partition "
255 				"sanity check failed:\n       No partition "
256 				"marked as Disk Partition\n");
257 			return -1;
258 		}
259 
260 		inftl->nb_boot_blocks = ip->firstUnit;
261 		inftl->numvunits = ip->virtualUnits;
262 		if (inftl->numvunits > (inftl->nb_blocks -
263 		    inftl->nb_boot_blocks - 2)) {
264 			printk(KERN_WARNING "INFTL: Media Header sanity check "
265 				"failed:\n        numvunits (%d) > nb_blocks "
266 				"(%d) - nb_boot_blocks(%d) - 2\n",
267 				inftl->numvunits, inftl->nb_blocks,
268 				inftl->nb_boot_blocks);
269 			return -1;
270 		}
271 
272 		inftl->mbd.size  = inftl->numvunits *
273 			(inftl->EraseSize / SECTORSIZE);
274 
275 		/*
276 		 * Block count is set to last used EUN (we won't need to keep
277 		 * any meta-data past that point).
278 		 */
279 		inftl->firstEUN = ip->firstUnit;
280 		inftl->lastEUN = ip->lastUnit;
281 		inftl->nb_blocks = ip->lastUnit + 1;
282 
283 		/* Memory alloc */
284 		inftl->PUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
285 		if (!inftl->PUtable) {
286 			printk(KERN_WARNING "INFTL: allocation of PUtable "
287 				"failed (%zd bytes)\n",
288 				inftl->nb_blocks * sizeof(u16));
289 			return -ENOMEM;
290 		}
291 
292 		inftl->VUtable = kmalloc(inftl->nb_blocks * sizeof(u16), GFP_KERNEL);
293 		if (!inftl->VUtable) {
294 			kfree(inftl->PUtable);
295 			printk(KERN_WARNING "INFTL: allocation of VUtable "
296 				"failed (%zd bytes)\n",
297 				inftl->nb_blocks * sizeof(u16));
298 			return -ENOMEM;
299 		}
300 
301 		/* Mark the blocks before INFTL MediaHeader as reserved */
302 		for (i = 0; i < inftl->nb_boot_blocks; i++)
303 			inftl->PUtable[i] = BLOCK_RESERVED;
304 		/* Mark all remaining blocks as potentially containing data */
305 		for (; i < inftl->nb_blocks; i++)
306 			inftl->PUtable[i] = BLOCK_NOTEXPLORED;
307 
308 		/* Mark this boot record (NFTL MediaHeader) block as reserved */
309 		inftl->PUtable[block] = BLOCK_RESERVED;
310 
311 		/* Read Bad Erase Unit Table and modify PUtable[] accordingly */
312 		for (i = 0; i < inftl->nb_blocks; i++) {
313 			int physblock;
314 			/* If any of the physical eraseblocks are bad, don't
315 			   use the unit. */
316 			for (physblock = 0; physblock < inftl->EraseSize; physblock += inftl->mbd.mtd->erasesize) {
317 				if (inftl->mbd.mtd->block_isbad(inftl->mbd.mtd, i * inftl->EraseSize + physblock))
318 					inftl->PUtable[i] = BLOCK_RESERVED;
319 			}
320 		}
321 
322 		inftl->MediaUnit = block;
323 		return 0;
324 	}
325 
326 	/* Not found. */
327 	return -1;
328 }
329 
330 static int memcmpb(void *a, int c, int n)
331 {
332 	int i;
333 	for (i = 0; i < n; i++) {
334 		if (c != ((unsigned char *)a)[i])
335 			return 1;
336 	}
337 	return 0;
338 }
339 
340 /*
341  * check_free_sector: check if a free sector is actually FREE,
342  *	i.e. All 0xff in data and oob area.
343  */
344 static int check_free_sectors(struct INFTLrecord *inftl, unsigned int address,
345 	int len, int check_oob)
346 {
347 	u8 buf[SECTORSIZE + inftl->mbd.mtd->oobsize];
348 	struct mtd_info *mtd = inftl->mbd.mtd;
349 	size_t retlen;
350 	int i;
351 
352 	for (i = 0; i < len; i += SECTORSIZE) {
353 		if (mtd->read(mtd, address, SECTORSIZE, &retlen, buf))
354 			return -1;
355 		if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
356 			return -1;
357 
358 		if (check_oob) {
359 			if(inftl_read_oob(mtd, address, mtd->oobsize,
360 					  &retlen, &buf[SECTORSIZE]) < 0)
361 				return -1;
362 			if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
363 				return -1;
364 		}
365 		address += SECTORSIZE;
366 	}
367 
368 	return 0;
369 }
370 
371 /*
372  * INFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase
373  *		 Unit and Update INFTL metadata. Each erase operation is
374  *		 checked with check_free_sectors.
375  *
376  * Return: 0 when succeed, -1 on error.
377  *
378  * ToDo: 1. Is it neceressary to check_free_sector after erasing ??
379  */
380 int INFTL_formatblock(struct INFTLrecord *inftl, int block)
381 {
382 	size_t retlen;
383 	struct inftl_unittail uci;
384 	struct erase_info *instr = &inftl->instr;
385 	struct mtd_info *mtd = inftl->mbd.mtd;
386 	int physblock;
387 
388 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_formatblock(inftl=%p,"
389 		"block=%d)\n", inftl, block);
390 
391 	memset(instr, 0, sizeof(struct erase_info));
392 
393 	/* FIXME: Shouldn't we be setting the 'discarded' flag to zero
394 	   _first_? */
395 
396 	/* Use async erase interface, test return code */
397 	instr->mtd = inftl->mbd.mtd;
398 	instr->addr = block * inftl->EraseSize;
399 	instr->len = inftl->mbd.mtd->erasesize;
400 	/* Erase one physical eraseblock at a time, even though the NAND api
401 	   allows us to group them.  This way we if we have a failure, we can
402 	   mark only the failed block in the bbt. */
403 	for (physblock = 0; physblock < inftl->EraseSize;
404 	     physblock += instr->len, instr->addr += instr->len) {
405 		mtd->erase(inftl->mbd.mtd, instr);
406 
407 		if (instr->state == MTD_ERASE_FAILED) {
408 			printk(KERN_WARNING "INFTL: error while formatting block %d\n",
409 				block);
410 			goto fail;
411 		}
412 
413 		/*
414 		 * Check the "freeness" of Erase Unit before updating metadata.
415 		 * FixMe: is this check really necessary? Since we have check
416 		 * the return code after the erase operation.
417 		 */
418 		if (check_free_sectors(inftl, instr->addr, instr->len, 1) != 0)
419 			goto fail;
420 	}
421 
422 	uci.EraseMark = cpu_to_le16(ERASE_MARK);
423 	uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
424 	uci.Reserved[0] = 0;
425 	uci.Reserved[1] = 0;
426 	uci.Reserved[2] = 0;
427 	uci.Reserved[3] = 0;
428 	instr->addr = block * inftl->EraseSize + SECTORSIZE * 2;
429 	if (inftl_write_oob(mtd, instr->addr + 8, 8, &retlen, (char *)&uci) < 0)
430 		goto fail;
431 	return 0;
432 fail:
433 	/* could not format, update the bad block table (caller is responsible
434 	   for setting the PUtable to BLOCK_RESERVED on failure) */
435 	inftl->mbd.mtd->block_markbad(inftl->mbd.mtd, instr->addr);
436 	return -1;
437 }
438 
439 /*
440  * format_chain: Format an invalid Virtual Unit chain. It frees all the Erase
441  *	Units in a Virtual Unit Chain, i.e. all the units are disconnected.
442  *
443  *	Since the chain is invalid then we will have to erase it from its
444  *	head (normally for INFTL we go from the oldest). But if it has a
445  *	loop then there is no oldest...
446  */
447 static void format_chain(struct INFTLrecord *inftl, unsigned int first_block)
448 {
449 	unsigned int block = first_block, block1;
450 
451 	printk(KERN_WARNING "INFTL: formatting chain at block %d\n",
452 		first_block);
453 
454 	for (;;) {
455 		block1 = inftl->PUtable[block];
456 
457 		printk(KERN_WARNING "INFTL: formatting block %d\n", block);
458 		if (INFTL_formatblock(inftl, block) < 0) {
459 			/*
460 			 * Cannot format !!!! Mark it as Bad Unit,
461 			 */
462 			inftl->PUtable[block] = BLOCK_RESERVED;
463 		} else {
464 			inftl->PUtable[block] = BLOCK_FREE;
465 		}
466 
467 		/* Goto next block on the chain */
468 		block = block1;
469 
470 		if (block == BLOCK_NIL || block >= inftl->lastEUN)
471 			break;
472 	}
473 }
474 
475 void INFTL_dumptables(struct INFTLrecord *s)
476 {
477 	int i;
478 
479 	printk("-------------------------------------------"
480 		"----------------------------------\n");
481 
482 	printk("VUtable[%d] ->", s->nb_blocks);
483 	for (i = 0; i < s->nb_blocks; i++) {
484 		if ((i % 8) == 0)
485 			printk("\n%04x: ", i);
486 		printk("%04x ", s->VUtable[i]);
487 	}
488 
489 	printk("\n-------------------------------------------"
490 		"----------------------------------\n");
491 
492 	printk("PUtable[%d-%d=%d] ->", s->firstEUN, s->lastEUN, s->nb_blocks);
493 	for (i = 0; i <= s->lastEUN; i++) {
494 		if ((i % 8) == 0)
495 			printk("\n%04x: ", i);
496 		printk("%04x ", s->PUtable[i]);
497 	}
498 
499 	printk("\n-------------------------------------------"
500 		"----------------------------------\n");
501 
502 	printk("INFTL ->\n"
503 		"  EraseSize       = %d\n"
504 		"  h/s/c           = %d/%d/%d\n"
505 		"  numvunits       = %d\n"
506 		"  firstEUN        = %d\n"
507 		"  lastEUN         = %d\n"
508 		"  numfreeEUNs     = %d\n"
509 		"  LastFreeEUN     = %d\n"
510 		"  nb_blocks       = %d\n"
511 		"  nb_boot_blocks  = %d",
512 		s->EraseSize, s->heads, s->sectors, s->cylinders,
513 		s->numvunits, s->firstEUN, s->lastEUN, s->numfreeEUNs,
514 		s->LastFreeEUN, s->nb_blocks, s->nb_boot_blocks);
515 
516 	printk("\n-------------------------------------------"
517 		"----------------------------------\n");
518 }
519 
520 void INFTL_dumpVUchains(struct INFTLrecord *s)
521 {
522 	int logical, block, i;
523 
524 	printk("-------------------------------------------"
525 		"----------------------------------\n");
526 
527 	printk("INFTL Virtual Unit Chains:\n");
528 	for (logical = 0; logical < s->nb_blocks; logical++) {
529 		block = s->VUtable[logical];
530 		if (block > s->nb_blocks)
531 			continue;
532 		printk("  LOGICAL %d --> %d ", logical, block);
533 		for (i = 0; i < s->nb_blocks; i++) {
534 			if (s->PUtable[block] == BLOCK_NIL)
535 				break;
536 			block = s->PUtable[block];
537 			printk("%d ", block);
538 		}
539 		printk("\n");
540 	}
541 
542 	printk("-------------------------------------------"
543 		"----------------------------------\n");
544 }
545 
546 int INFTL_mount(struct INFTLrecord *s)
547 {
548 	struct mtd_info *mtd = s->mbd.mtd;
549 	unsigned int block, first_block, prev_block, last_block;
550 	unsigned int first_logical_block, logical_block, erase_mark;
551 	int chain_length, do_format_chain;
552 	struct inftl_unithead1 h0;
553 	struct inftl_unittail h1;
554 	size_t retlen;
555 	int i;
556 	u8 *ANACtable, ANAC;
557 
558 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_mount(inftl=%p)\n", s);
559 
560 	/* Search for INFTL MediaHeader and Spare INFTL Media Header */
561 	if (find_boot_record(s) < 0) {
562 		printk(KERN_WARNING "INFTL: could not find valid boot record?\n");
563 		return -ENXIO;
564 	}
565 
566 	/* Init the logical to physical table */
567 	for (i = 0; i < s->nb_blocks; i++)
568 		s->VUtable[i] = BLOCK_NIL;
569 
570 	logical_block = block = BLOCK_NIL;
571 
572 	/* Temporary buffer to store ANAC numbers. */
573 	ANACtable = kcalloc(s->nb_blocks, sizeof(u8), GFP_KERNEL);
574 	if (!ANACtable) {
575 		printk(KERN_WARNING "INFTL: allocation of ANACtable "
576 				"failed (%zd bytes)\n",
577 				s->nb_blocks * sizeof(u8));
578 		return -ENOMEM;
579 	}
580 
581 	/*
582 	 * First pass is to explore each physical unit, and construct the
583 	 * virtual chains that exist (newest physical unit goes into VUtable).
584 	 * Any block that is in any way invalid will be left in the
585 	 * NOTEXPLORED state. Then at the end we will try to format it and
586 	 * mark it as free.
587 	 */
588 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: pass 1, explore each unit\n");
589 	for (first_block = s->firstEUN; first_block <= s->lastEUN; first_block++) {
590 		if (s->PUtable[first_block] != BLOCK_NOTEXPLORED)
591 			continue;
592 
593 		do_format_chain = 0;
594 		first_logical_block = BLOCK_NIL;
595 		last_block = BLOCK_NIL;
596 		block = first_block;
597 
598 		for (chain_length = 0; ; chain_length++) {
599 
600 			if ((chain_length == 0) &&
601 			    (s->PUtable[block] != BLOCK_NOTEXPLORED)) {
602 				/* Nothing to do here, onto next block */
603 				break;
604 			}
605 
606 			if (inftl_read_oob(mtd, block * s->EraseSize + 8,
607 					   8, &retlen, (char *)&h0) < 0 ||
608 			    inftl_read_oob(mtd, block * s->EraseSize +
609 					   2 * SECTORSIZE + 8, 8, &retlen,
610 					   (char *)&h1) < 0) {
611 				/* Should never happen? */
612 				do_format_chain++;
613 				break;
614 			}
615 
616 			logical_block = le16_to_cpu(h0.virtualUnitNo);
617 			prev_block = le16_to_cpu(h0.prevUnitNo);
618 			erase_mark = le16_to_cpu((h1.EraseMark | h1.EraseMark1));
619 			ANACtable[block] = h0.ANAC;
620 
621 			/* Previous block is relative to start of Partition */
622 			if (prev_block < s->nb_blocks)
623 				prev_block += s->firstEUN;
624 
625 			/* Already explored partial chain? */
626 			if (s->PUtable[block] != BLOCK_NOTEXPLORED) {
627 				/* Check if chain for this logical */
628 				if (logical_block == first_logical_block) {
629 					if (last_block != BLOCK_NIL)
630 						s->PUtable[last_block] = block;
631 				}
632 				break;
633 			}
634 
635 			/* Check for invalid block */
636 			if (erase_mark != ERASE_MARK) {
637 				printk(KERN_WARNING "INFTL: corrupt block %d "
638 					"in chain %d, chain length %d, erase "
639 					"mark 0x%x?\n", block, first_block,
640 					chain_length, erase_mark);
641 				/*
642 				 * Assume end of chain, probably incomplete
643 				 * fold/erase...
644 				 */
645 				if (chain_length == 0)
646 					do_format_chain++;
647 				break;
648 			}
649 
650 			/* Check for it being free already then... */
651 			if ((logical_block == BLOCK_FREE) ||
652 			    (logical_block == BLOCK_NIL)) {
653 				s->PUtable[block] = BLOCK_FREE;
654 				break;
655 			}
656 
657 			/* Sanity checks on block numbers */
658 			if ((logical_block >= s->nb_blocks) ||
659 			    ((prev_block >= s->nb_blocks) &&
660 			     (prev_block != BLOCK_NIL))) {
661 				if (chain_length > 0) {
662 					printk(KERN_WARNING "INFTL: corrupt "
663 						"block %d in chain %d?\n",
664 						block, first_block);
665 					do_format_chain++;
666 				}
667 				break;
668 			}
669 
670 			if (first_logical_block == BLOCK_NIL) {
671 				first_logical_block = logical_block;
672 			} else {
673 				if (first_logical_block != logical_block) {
674 					/* Normal for folded chain... */
675 					break;
676 				}
677 			}
678 
679 			/*
680 			 * Current block is valid, so if we followed a virtual
681 			 * chain to get here then we can set the previous
682 			 * block pointer in our PUtable now. Then move onto
683 			 * the previous block in the chain.
684 			 */
685 			s->PUtable[block] = BLOCK_NIL;
686 			if (last_block != BLOCK_NIL)
687 				s->PUtable[last_block] = block;
688 			last_block = block;
689 			block = prev_block;
690 
691 			/* Check for end of chain */
692 			if (block == BLOCK_NIL)
693 				break;
694 
695 			/* Validate next block before following it... */
696 			if (block > s->lastEUN) {
697 				printk(KERN_WARNING "INFTL: invalid previous "
698 					"block %d in chain %d?\n", block,
699 					first_block);
700 				do_format_chain++;
701 				break;
702 			}
703 		}
704 
705 		if (do_format_chain) {
706 			format_chain(s, first_block);
707 			continue;
708 		}
709 
710 		/*
711 		 * Looks like a valid chain then. It may not really be the
712 		 * newest block in the chain, but it is the newest we have
713 		 * found so far. We might update it in later iterations of
714 		 * this loop if we find something newer.
715 		 */
716 		s->VUtable[first_logical_block] = first_block;
717 		logical_block = BLOCK_NIL;
718 	}
719 
720 #ifdef CONFIG_MTD_DEBUG_VERBOSE
721 	if (CONFIG_MTD_DEBUG_VERBOSE >= 2)
722 		INFTL_dumptables(s);
723 #endif
724 
725 	/*
726 	 * Second pass, check for infinite loops in chains. These are
727 	 * possible because we don't update the previous pointers when
728 	 * we fold chains. No big deal, just fix them up in PUtable.
729 	 */
730 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: pass 2, validate virtual chains\n");
731 	for (logical_block = 0; logical_block < s->numvunits; logical_block++) {
732 		block = s->VUtable[logical_block];
733 		last_block = BLOCK_NIL;
734 
735 		/* Check for free/reserved/nil */
736 		if (block >= BLOCK_RESERVED)
737 			continue;
738 
739 		ANAC = ANACtable[block];
740 		for (i = 0; i < s->numvunits; i++) {
741 			if (s->PUtable[block] == BLOCK_NIL)
742 				break;
743 			if (s->PUtable[block] > s->lastEUN) {
744 				printk(KERN_WARNING "INFTL: invalid prev %d, "
745 					"in virtual chain %d\n",
746 					s->PUtable[block], logical_block);
747 				s->PUtable[block] = BLOCK_NIL;
748 
749 			}
750 			if (ANACtable[block] != ANAC) {
751 				/*
752 				 * Chain must point back to itself. This is ok,
753 				 * but we will need adjust the tables with this
754 				 * newest block and oldest block.
755 				 */
756 				s->VUtable[logical_block] = block;
757 				s->PUtable[last_block] = BLOCK_NIL;
758 				break;
759 			}
760 
761 			ANAC--;
762 			last_block = block;
763 			block = s->PUtable[block];
764 		}
765 
766 		if (i >= s->nb_blocks) {
767 			/*
768 			 * Uhoo, infinite chain with valid ANACS!
769 			 * Format whole chain...
770 			 */
771 			format_chain(s, first_block);
772 		}
773 	}
774 
775 #ifdef CONFIG_MTD_DEBUG_VERBOSE
776 	if (CONFIG_MTD_DEBUG_VERBOSE >= 2)
777 		INFTL_dumptables(s);
778 	if (CONFIG_MTD_DEBUG_VERBOSE >= 2)
779 		INFTL_dumpVUchains(s);
780 #endif
781 
782 	/*
783 	 * Third pass, format unreferenced blocks and init free block count.
784 	 */
785 	s->numfreeEUNs = 0;
786 	s->LastFreeEUN = BLOCK_NIL;
787 
788 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: pass 3, format unused blocks\n");
789 	for (block = s->firstEUN; block <= s->lastEUN; block++) {
790 		if (s->PUtable[block] == BLOCK_NOTEXPLORED) {
791 			printk("INFTL: unreferenced block %d, formatting it\n",
792 				block);
793 			if (INFTL_formatblock(s, block) < 0)
794 				s->PUtable[block] = BLOCK_RESERVED;
795 			else
796 				s->PUtable[block] = BLOCK_FREE;
797 		}
798 		if (s->PUtable[block] == BLOCK_FREE) {
799 			s->numfreeEUNs++;
800 			if (s->LastFreeEUN == BLOCK_NIL)
801 				s->LastFreeEUN = block;
802 		}
803 	}
804 
805 	kfree(ANACtable);
806 	return 0;
807 }
808