xref: /linux/drivers/mtd/inftlcore.c (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
1 /*
2  * inftlcore.c -- Linux driver for Inverse Flash Translation Layer (INFTL)
3  *
4  * (C) Copyright 2002, Greg Ungerer (gerg@snapgear.com)
5  *
6  * Based heavily on the nftlcore.c code which is:
7  * (c) 1999 Machine Vision Holdings, Inc.
8  * Author: David Woodhouse <dwmw2@infradead.org>
9  *
10  * $Id: inftlcore.c,v 1.19 2005/11/07 11:14:20 gleixner Exp $
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License as published by
14  * the Free Software Foundation; either version 2 of the License, or
15  * (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
25  */
26 
27 #include <linux/config.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/delay.h>
31 #include <linux/slab.h>
32 #include <linux/sched.h>
33 #include <linux/init.h>
34 #include <linux/kmod.h>
35 #include <linux/hdreg.h>
36 #include <linux/mtd/mtd.h>
37 #include <linux/mtd/nftl.h>
38 #include <linux/mtd/inftl.h>
39 #include <asm/uaccess.h>
40 #include <asm/errno.h>
41 #include <asm/io.h>
42 
43 /*
44  * Maximum number of loops while examining next block, to have a
45  * chance to detect consistency problems (they should never happen
46  * because of the checks done in the mounting.
47  */
48 #define MAX_LOOPS 10000
49 
50 static void inftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
51 {
52 	struct INFTLrecord *inftl;
53 	unsigned long temp;
54 
55 	if (mtd->type != MTD_NANDFLASH)
56 		return;
57 	/* OK, this is moderately ugly.  But probably safe.  Alternatives? */
58 	if (memcmp(mtd->name, "DiskOnChip", 10))
59 		return;
60 
61 	if (!mtd->block_isbad) {
62 		printk(KERN_ERR
63 "INFTL no longer supports the old DiskOnChip drivers loaded via docprobe.\n"
64 "Please use the new diskonchip driver under the NAND subsystem.\n");
65 		return;
66 	}
67 
68 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: add_mtd for %s\n", mtd->name);
69 
70 	inftl = kmalloc(sizeof(*inftl), GFP_KERNEL);
71 
72 	if (!inftl) {
73 		printk(KERN_WARNING "INFTL: Out of memory for data structures\n");
74 		return;
75 	}
76 	memset(inftl, 0, sizeof(*inftl));
77 
78 	inftl->mbd.mtd = mtd;
79 	inftl->mbd.devnum = -1;
80 	inftl->mbd.blksize = 512;
81 	inftl->mbd.tr = tr;
82 	memcpy(&inftl->oobinfo, &mtd->oobinfo, sizeof(struct nand_oobinfo));
83 	inftl->oobinfo.useecc = MTD_NANDECC_PLACEONLY;
84 
85         if (INFTL_mount(inftl) < 0) {
86 		printk(KERN_WARNING "INFTL: could not mount device\n");
87 		kfree(inftl);
88 		return;
89         }
90 
91 	/* OK, it's a new one. Set up all the data structures. */
92 
93 	/* Calculate geometry */
94 	inftl->cylinders = 1024;
95 	inftl->heads = 16;
96 
97 	temp = inftl->cylinders * inftl->heads;
98 	inftl->sectors = inftl->mbd.size / temp;
99 	if (inftl->mbd.size % temp) {
100 		inftl->sectors++;
101 		temp = inftl->cylinders * inftl->sectors;
102 		inftl->heads = inftl->mbd.size / temp;
103 
104 		if (inftl->mbd.size % temp) {
105 			inftl->heads++;
106 			temp = inftl->heads * inftl->sectors;
107 			inftl->cylinders = inftl->mbd.size / temp;
108 		}
109 	}
110 
111 	if (inftl->mbd.size != inftl->heads * inftl->cylinders * inftl->sectors) {
112 		/*
113 		  Oh no we don't have
114 		   mbd.size == heads * cylinders * sectors
115 		*/
116 		printk(KERN_WARNING "INFTL: cannot calculate a geometry to "
117 		       "match size of 0x%lx.\n", inftl->mbd.size);
118 		printk(KERN_WARNING "INFTL: using C:%d H:%d S:%d "
119 			"(== 0x%lx sects)\n",
120 			inftl->cylinders, inftl->heads , inftl->sectors,
121 			(long)inftl->cylinders * (long)inftl->heads *
122 			(long)inftl->sectors );
123 	}
124 
125 	if (add_mtd_blktrans_dev(&inftl->mbd)) {
126 		kfree(inftl->PUtable);
127 		kfree(inftl->VUtable);
128 		kfree(inftl);
129 		return;
130 	}
131 #ifdef PSYCHO_DEBUG
132 	printk(KERN_INFO "INFTL: Found new inftl%c\n", inftl->mbd.devnum + 'a');
133 #endif
134 	return;
135 }
136 
137 static void inftl_remove_dev(struct mtd_blktrans_dev *dev)
138 {
139 	struct INFTLrecord *inftl = (void *)dev;
140 
141 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: remove_dev (i=%d)\n", dev->devnum);
142 
143 	del_mtd_blktrans_dev(dev);
144 
145 	kfree(inftl->PUtable);
146 	kfree(inftl->VUtable);
147 	kfree(inftl);
148 }
149 
150 /*
151  * Actual INFTL access routines.
152  */
153 
154 /*
155  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
156  *	This function is used when the give Virtual Unit Chain.
157  */
158 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
159 {
160 	u16 pot = inftl->LastFreeEUN;
161 	int silly = inftl->nb_blocks;
162 
163 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
164 		"desperate=%d)\n", inftl, desperate);
165 
166 	/*
167 	 * Normally, we force a fold to happen before we run out of free
168 	 * blocks completely.
169 	 */
170 	if (!desperate && inftl->numfreeEUNs < 2) {
171 		DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
172 			"EUNs (%d)\n", inftl->numfreeEUNs);
173 		return 0xffff;
174 	}
175 
176 	/* Scan for a free block */
177 	do {
178 		if (inftl->PUtable[pot] == BLOCK_FREE) {
179 			inftl->LastFreeEUN = pot;
180 			return pot;
181 		}
182 
183 		if (++pot > inftl->lastEUN)
184 			pot = 0;
185 
186 		if (!silly--) {
187 			printk(KERN_WARNING "INFTL: no free blocks found!  "
188 				"EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
189 			return BLOCK_NIL;
190 		}
191 	} while (pot != inftl->LastFreeEUN);
192 
193 	return BLOCK_NIL;
194 }
195 
196 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
197 {
198 	u16 BlockMap[MAX_SECTORS_PER_UNIT];
199 	unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
200 	unsigned int thisEUN, prevEUN, status;
201 	int block, silly;
202 	unsigned int targetEUN;
203 	struct inftl_oob oob;
204         size_t retlen;
205 
206 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
207 		"pending=%d)\n", inftl, thisVUC, pendingblock);
208 
209 	memset(BlockMap, 0xff, sizeof(BlockMap));
210 	memset(BlockDeleted, 0, sizeof(BlockDeleted));
211 
212 	thisEUN = targetEUN = inftl->VUtable[thisVUC];
213 
214 	if (thisEUN == BLOCK_NIL) {
215 		printk(KERN_WARNING "INFTL: trying to fold non-existent "
216 		       "Virtual Unit Chain %d!\n", thisVUC);
217 		return BLOCK_NIL;
218 	}
219 
220 	/*
221 	 * Scan to find the Erase Unit which holds the actual data for each
222 	 * 512-byte block within the Chain.
223 	 */
224         silly = MAX_LOOPS;
225 	while (thisEUN < inftl->nb_blocks) {
226 		for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
227 			if ((BlockMap[block] != 0xffff) || BlockDeleted[block])
228 				continue;
229 
230 			if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize)
231 			     + (block * SECTORSIZE), 16 , &retlen,
232 			     (char *)&oob) < 0)
233 				status = SECTOR_IGNORE;
234 			else
235                         	status = oob.b.Status | oob.b.Status1;
236 
237 			switch(status) {
238 			case SECTOR_FREE:
239 			case SECTOR_IGNORE:
240 				break;
241 			case SECTOR_USED:
242 				BlockMap[block] = thisEUN;
243 				continue;
244 			case SECTOR_DELETED:
245 				BlockDeleted[block] = 1;
246 				continue;
247 			default:
248 				printk(KERN_WARNING "INFTL: unknown status "
249 					"for block %d in EUN %d: %x\n",
250 					block, thisEUN, status);
251 				break;
252 			}
253 		}
254 
255 		if (!silly--) {
256 			printk(KERN_WARNING "INFTL: infinite loop in Virtual "
257 				"Unit Chain 0x%x\n", thisVUC);
258 			return BLOCK_NIL;
259 		}
260 
261 		thisEUN = inftl->PUtable[thisEUN];
262 	}
263 
264 	/*
265 	 * OK. We now know the location of every block in the Virtual Unit
266 	 * Chain, and the Erase Unit into which we are supposed to be copying.
267 	 * Go for it.
268 	 */
269 	DEBUG(MTD_DEBUG_LEVEL1, "INFTL: folding chain %d into unit %d\n",
270 		thisVUC, targetEUN);
271 
272 	for (block = 0; block < inftl->EraseSize/SECTORSIZE ; block++) {
273 		unsigned char movebuf[SECTORSIZE];
274 		int ret;
275 
276 		/*
277 		 * If it's in the target EUN already, or if it's pending write,
278 		 * do nothing.
279 		 */
280 		if (BlockMap[block] == targetEUN || (pendingblock ==
281 		    (thisVUC * (inftl->EraseSize / SECTORSIZE) + block))) {
282 			continue;
283 		}
284 
285                 /*
286 		 * Copy only in non free block (free blocks can only
287                  * happen in case of media errors or deleted blocks).
288 		 */
289                 if (BlockMap[block] == BLOCK_NIL)
290                         continue;
291 
292                 ret = MTD_READ(inftl->mbd.mtd, (inftl->EraseSize *
293 			BlockMap[block]) + (block * SECTORSIZE), SECTORSIZE,
294 			&retlen, movebuf);
295                 if (ret < 0) {
296 			ret = MTD_READ(inftl->mbd.mtd, (inftl->EraseSize *
297 				BlockMap[block]) + (block * SECTORSIZE),
298 				SECTORSIZE, &retlen, movebuf);
299 			if (ret != -EIO)
300                         	DEBUG(MTD_DEBUG_LEVEL1, "INFTL: error went "
301 					"away on retry?\n");
302                 }
303                 memset(&oob, 0xff, sizeof(struct inftl_oob));
304                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
305                 MTD_WRITEECC(inftl->mbd.mtd, (inftl->EraseSize * targetEUN) +
306 			(block * SECTORSIZE), SECTORSIZE, &retlen,
307 			movebuf, (char *)&oob, &inftl->oobinfo);
308 	}
309 
310 	/*
311 	 * Newest unit in chain now contains data from _all_ older units.
312 	 * So go through and erase each unit in chain, oldest first. (This
313 	 * is important, by doing oldest first if we crash/reboot then it
314 	 * it is relatively simple to clean up the mess).
315 	 */
316 	DEBUG(MTD_DEBUG_LEVEL1, "INFTL: want to erase virtual chain %d\n",
317 		thisVUC);
318 
319 	for (;;) {
320 		/* Find oldest unit in chain. */
321 		thisEUN = inftl->VUtable[thisVUC];
322 		prevEUN = BLOCK_NIL;
323 		while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
324 			prevEUN = thisEUN;
325 			thisEUN = inftl->PUtable[thisEUN];
326 		}
327 
328 		/* Check if we are all done */
329 		if (thisEUN == targetEUN)
330 			break;
331 
332                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
333 			/*
334 			 * Could not erase : mark block as reserved.
335 			 */
336 			inftl->PUtable[thisEUN] = BLOCK_RESERVED;
337                 } else {
338 			/* Correctly erased : mark it as free */
339 			inftl->PUtable[thisEUN] = BLOCK_FREE;
340 			inftl->PUtable[prevEUN] = BLOCK_NIL;
341 			inftl->numfreeEUNs++;
342                 }
343 	}
344 
345 	return targetEUN;
346 }
347 
348 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
349 {
350 	/*
351 	 * This is the part that needs some cleverness applied.
352 	 * For now, I'm doing the minimum applicable to actually
353 	 * get the thing to work.
354 	 * Wear-levelling and other clever stuff needs to be implemented
355 	 * and we also need to do some assessment of the results when
356 	 * the system loses power half-way through the routine.
357 	 */
358 	u16 LongestChain = 0;
359 	u16 ChainLength = 0, thislen;
360 	u16 chain, EUN;
361 
362 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
363 		"pending=%d)\n", inftl, pendingblock);
364 
365 	for (chain = 0; chain < inftl->nb_blocks; chain++) {
366 		EUN = inftl->VUtable[chain];
367 		thislen = 0;
368 
369 		while (EUN <= inftl->lastEUN) {
370 			thislen++;
371 			EUN = inftl->PUtable[EUN];
372 			if (thislen > 0xff00) {
373 				printk(KERN_WARNING "INFTL: endless loop in "
374 					"Virtual Chain %d: Unit %x\n",
375 					chain, EUN);
376 				/*
377 				 * Actually, don't return failure.
378 				 * Just ignore this chain and get on with it.
379 				 */
380 				thislen = 0;
381 				break;
382 			}
383 		}
384 
385 		if (thislen > ChainLength) {
386 			ChainLength = thislen;
387 			LongestChain = chain;
388 		}
389 	}
390 
391 	if (ChainLength < 2) {
392 		printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
393 			"for folding. Failing request\n");
394 		return BLOCK_NIL;
395 	}
396 
397 	return INFTL_foldchain(inftl, LongestChain, pendingblock);
398 }
399 
400 static int nrbits(unsigned int val, int bitcount)
401 {
402 	int i, total = 0;
403 
404 	for (i = 0; (i < bitcount); i++)
405 		total += (((0x1 << i) & val) ? 1 : 0);
406 	return total;
407 }
408 
409 /*
410  * INFTL_findwriteunit: Return the unit number into which we can write
411  *                      for this block. Make it available if it isn't already.
412  */
413 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
414 {
415 	unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
416 	unsigned int thisEUN, writeEUN, prev_block, status;
417 	unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
418 	struct inftl_oob oob;
419 	struct inftl_bci bci;
420 	unsigned char anac, nacs, parity;
421 	size_t retlen;
422 	int silly, silly2 = 3;
423 
424 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findwriteunit(inftl=%p,"
425 		"block=%d)\n", inftl, block);
426 
427 	do {
428 		/*
429 		 * Scan the media to find a unit in the VUC which has
430 		 * a free space for the block in question.
431 		 */
432 		writeEUN = BLOCK_NIL;
433 		thisEUN = inftl->VUtable[thisVUC];
434 		silly = MAX_LOOPS;
435 
436 		while (thisEUN <= inftl->lastEUN) {
437 			MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize) +
438 				blockofs, 8, &retlen, (char *)&bci);
439 
440                         status = bci.Status | bci.Status1;
441 			DEBUG(MTD_DEBUG_LEVEL3, "INFTL: status of block %d in "
442 				"EUN %d is %x\n", block , writeEUN, status);
443 
444 			switch(status) {
445 			case SECTOR_FREE:
446 				writeEUN = thisEUN;
447 				break;
448 			case SECTOR_DELETED:
449 			case SECTOR_USED:
450 				/* Can't go any further */
451 				goto hitused;
452 			case SECTOR_IGNORE:
453 				break;
454 			default:
455 				/*
456 				 * Invalid block. Don't use it any more.
457 				 * Must implement.
458 				 */
459 				break;
460 			}
461 
462 			if (!silly--) {
463 				printk(KERN_WARNING "INFTL: infinite loop in "
464 					"Virtual Unit Chain 0x%x\n", thisVUC);
465 				return 0xffff;
466 			}
467 
468 			/* Skip to next block in chain */
469 			thisEUN = inftl->PUtable[thisEUN];
470 		}
471 
472 hitused:
473 		if (writeEUN != BLOCK_NIL)
474 			return writeEUN;
475 
476 
477 		/*
478 		 * OK. We didn't find one in the existing chain, or there
479 		 * is no existing chain. Allocate a new one.
480 		 */
481 		writeEUN = INFTL_findfreeblock(inftl, 0);
482 
483 		if (writeEUN == BLOCK_NIL) {
484 			/*
485 			 * That didn't work - there were no free blocks just
486 			 * waiting to be picked up. We're going to have to fold
487 			 * a chain to make room.
488 			 */
489 			thisEUN = INFTL_makefreeblock(inftl, 0xffff);
490 
491 			/*
492 			 * Hopefully we free something, lets try again.
493 			 * This time we are desperate...
494 			 */
495 			DEBUG(MTD_DEBUG_LEVEL1, "INFTL: using desperate==1 "
496 				"to find free EUN to accommodate write to "
497 				"VUC %d\n", thisVUC);
498 			writeEUN = INFTL_findfreeblock(inftl, 1);
499 			if (writeEUN == BLOCK_NIL) {
500 				/*
501 				 * Ouch. This should never happen - we should
502 				 * always be able to make some room somehow.
503 				 * If we get here, we've allocated more storage
504 				 * space than actual media, or our makefreeblock
505 				 * routine is missing something.
506 				 */
507 				printk(KERN_WARNING "INFTL: cannot make free "
508 					"space.\n");
509 #ifdef DEBUG
510 				INFTL_dumptables(inftl);
511 				INFTL_dumpVUchains(inftl);
512 #endif
513 				return BLOCK_NIL;
514 			}
515 		}
516 
517 		/*
518 		 * Insert new block into virtual chain. Firstly update the
519 		 * block headers in flash...
520 		 */
521 		anac = 0;
522 		nacs = 0;
523 		thisEUN = inftl->VUtable[thisVUC];
524 		if (thisEUN != BLOCK_NIL) {
525 			MTD_READOOB(inftl->mbd.mtd, thisEUN * inftl->EraseSize
526 				+ 8, 8, &retlen, (char *)&oob.u);
527 			anac = oob.u.a.ANAC + 1;
528 			nacs = oob.u.a.NACs + 1;
529 		}
530 
531 		prev_block = inftl->VUtable[thisVUC];
532 		if (prev_block < inftl->nb_blocks)
533 			prev_block -= inftl->firstEUN;
534 
535 		parity = (nrbits(thisVUC, 16) & 0x1) ? 0x1 : 0;
536 		parity |= (nrbits(prev_block, 16) & 0x1) ? 0x2 : 0;
537 		parity |= (nrbits(anac, 8) & 0x1) ? 0x4 : 0;
538 		parity |= (nrbits(nacs, 8) & 0x1) ? 0x8 : 0;
539 
540 		oob.u.a.virtualUnitNo = cpu_to_le16(thisVUC);
541 		oob.u.a.prevUnitNo = cpu_to_le16(prev_block);
542 		oob.u.a.ANAC = anac;
543 		oob.u.a.NACs = nacs;
544 		oob.u.a.parityPerField = parity;
545 		oob.u.a.discarded = 0xaa;
546 
547 		MTD_WRITEOOB(inftl->mbd.mtd, writeEUN * inftl->EraseSize + 8, 8,
548 			&retlen, (char *)&oob.u);
549 
550 		/* Also back up header... */
551 		oob.u.b.virtualUnitNo = cpu_to_le16(thisVUC);
552 		oob.u.b.prevUnitNo = cpu_to_le16(prev_block);
553 		oob.u.b.ANAC = anac;
554 		oob.u.b.NACs = nacs;
555 		oob.u.b.parityPerField = parity;
556 		oob.u.b.discarded = 0xaa;
557 
558 		MTD_WRITEOOB(inftl->mbd.mtd, writeEUN * inftl->EraseSize +
559 			SECTORSIZE * 4 + 8, 8, &retlen, (char *)&oob.u);
560 
561 		inftl->PUtable[writeEUN] = inftl->VUtable[thisVUC];
562 		inftl->VUtable[thisVUC] = writeEUN;
563 
564 		inftl->numfreeEUNs--;
565 		return writeEUN;
566 
567 	} while (silly2--);
568 
569 	printk(KERN_WARNING "INFTL: error folding to make room for Virtual "
570 		"Unit Chain 0x%x\n", thisVUC);
571 	return 0xffff;
572 }
573 
574 /*
575  * Given a Virtual Unit Chain, see if it can be deleted, and if so do it.
576  */
577 static void INFTL_trydeletechain(struct INFTLrecord *inftl, unsigned thisVUC)
578 {
579 	unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
580 	unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
581 	unsigned int thisEUN, status;
582 	int block, silly;
583 	struct inftl_bci bci;
584 	size_t retlen;
585 
586 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
587 		"thisVUC=%d)\n", inftl, thisVUC);
588 
589 	memset(BlockUsed, 0, sizeof(BlockUsed));
590 	memset(BlockDeleted, 0, sizeof(BlockDeleted));
591 
592 	thisEUN = inftl->VUtable[thisVUC];
593 	if (thisEUN == BLOCK_NIL) {
594 		printk(KERN_WARNING "INFTL: trying to delete non-existent "
595 		       "Virtual Unit Chain %d!\n", thisVUC);
596 		return;
597 	}
598 
599 	/*
600 	 * Scan through the Erase Units to determine whether any data is in
601 	 * each of the 512-byte blocks within the Chain.
602 	 */
603 	silly = MAX_LOOPS;
604 	while (thisEUN < inftl->nb_blocks) {
605 		for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
606 			if (BlockUsed[block] || BlockDeleted[block])
607 				continue;
608 
609 			if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize)
610 			    + (block * SECTORSIZE), 8 , &retlen,
611 			    (char *)&bci) < 0)
612 				status = SECTOR_IGNORE;
613 			else
614 				status = bci.Status | bci.Status1;
615 
616 			switch(status) {
617 			case SECTOR_FREE:
618 			case SECTOR_IGNORE:
619 				break;
620 			case SECTOR_USED:
621 				BlockUsed[block] = 1;
622 				continue;
623 			case SECTOR_DELETED:
624 				BlockDeleted[block] = 1;
625 				continue;
626 			default:
627 				printk(KERN_WARNING "INFTL: unknown status "
628 					"for block %d in EUN %d: 0x%x\n",
629 					block, thisEUN, status);
630 			}
631 		}
632 
633 		if (!silly--) {
634 			printk(KERN_WARNING "INFTL: infinite loop in Virtual "
635 				"Unit Chain 0x%x\n", thisVUC);
636 			return;
637 		}
638 
639 		thisEUN = inftl->PUtable[thisEUN];
640 	}
641 
642 	for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
643 		if (BlockUsed[block])
644 			return;
645 
646 	/*
647 	 * For each block in the chain free it and make it available
648 	 * for future use. Erase from the oldest unit first.
649 	 */
650 	DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
651 
652 	for (;;) {
653 		u16 *prevEUN = &inftl->VUtable[thisVUC];
654 		thisEUN = *prevEUN;
655 
656 		/* If the chain is all gone already, we're done */
657 		if (thisEUN == BLOCK_NIL) {
658 			DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
659 			return;
660 		}
661 
662 		/* Find oldest unit in chain. */
663 		while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
664 			BUG_ON(thisEUN >= inftl->nb_blocks);
665 
666 			prevEUN = &inftl->PUtable[thisEUN];
667 			thisEUN = *prevEUN;
668 		}
669 
670 		DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
671 		      thisEUN, thisVUC);
672 
673                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
674 			/*
675 			 * Could not erase : mark block as reserved.
676 			 */
677 			inftl->PUtable[thisEUN] = BLOCK_RESERVED;
678                 } else {
679 			/* Correctly erased : mark it as free */
680 			inftl->PUtable[thisEUN] = BLOCK_FREE;
681 			inftl->numfreeEUNs++;
682 		}
683 
684 		/* Now sort out whatever was pointing to it... */
685 		*prevEUN = BLOCK_NIL;
686 
687 		/* Ideally we'd actually be responsive to new
688 		   requests while we're doing this -- if there's
689 		   free space why should others be made to wait? */
690 		cond_resched();
691 	}
692 
693 	inftl->VUtable[thisVUC] = BLOCK_NIL;
694 }
695 
696 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
697 {
698 	unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
699 	unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
700 	unsigned int status;
701 	int silly = MAX_LOOPS;
702 	size_t retlen;
703 	struct inftl_bci bci;
704 
705 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
706 		"block=%d)\n", inftl, block);
707 
708 	while (thisEUN < inftl->nb_blocks) {
709 		if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize) +
710 		    blockofs, 8, &retlen, (char *)&bci) < 0)
711 			status = SECTOR_IGNORE;
712 		else
713 			status = bci.Status | bci.Status1;
714 
715 		switch (status) {
716 		case SECTOR_FREE:
717 		case SECTOR_IGNORE:
718 			break;
719 		case SECTOR_DELETED:
720 			thisEUN = BLOCK_NIL;
721 			goto foundit;
722 		case SECTOR_USED:
723 			goto foundit;
724 		default:
725 			printk(KERN_WARNING "INFTL: unknown status for "
726 				"block %d in EUN %d: 0x%x\n",
727 				block, thisEUN, status);
728 			break;
729 		}
730 
731 		if (!silly--) {
732 			printk(KERN_WARNING "INFTL: infinite loop in Virtual "
733 				"Unit Chain 0x%x\n",
734 				block / (inftl->EraseSize / SECTORSIZE));
735 			return 1;
736 		}
737 		thisEUN = inftl->PUtable[thisEUN];
738 	}
739 
740 foundit:
741 	if (thisEUN != BLOCK_NIL) {
742 		loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
743 
744 		if (MTD_READOOB(inftl->mbd.mtd, ptr, 8, &retlen, (char *)&bci) < 0)
745 			return -EIO;
746 		bci.Status = bci.Status1 = SECTOR_DELETED;
747 		if (MTD_WRITEOOB(inftl->mbd.mtd, ptr, 8, &retlen, (char *)&bci) < 0)
748 			return -EIO;
749 		INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
750 	}
751 	return 0;
752 }
753 
754 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
755 			    char *buffer)
756 {
757 	struct INFTLrecord *inftl = (void *)mbd;
758 	unsigned int writeEUN;
759 	unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
760 	size_t retlen;
761 	struct inftl_oob oob;
762 	char *p, *pend;
763 
764 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
765 		"buffer=%p)\n", inftl, block, buffer);
766 
767 	/* Is block all zero? */
768 	pend = buffer + SECTORSIZE;
769 	for (p = buffer; p < pend && !*p; p++)
770 		;
771 
772 	if (p < pend) {
773 		writeEUN = INFTL_findwriteunit(inftl, block);
774 
775 		if (writeEUN == BLOCK_NIL) {
776 			printk(KERN_WARNING "inftl_writeblock(): cannot find "
777 				"block to write to\n");
778 			/*
779 			 * If we _still_ haven't got a block to use,
780 			 * we're screwed.
781 			 */
782 			return 1;
783 		}
784 
785 		memset(&oob, 0xff, sizeof(struct inftl_oob));
786 		oob.b.Status = oob.b.Status1 = SECTOR_USED;
787 		MTD_WRITEECC(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
788 			blockofs, SECTORSIZE, &retlen, (char *)buffer,
789 			(char *)&oob, &inftl->oobinfo);
790 		/*
791 		 * need to write SECTOR_USED flags since they are not written
792 		 * in mtd_writeecc
793 		 */
794 	} else {
795 		INFTL_deleteblock(inftl, block);
796 	}
797 
798 	return 0;
799 }
800 
801 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
802 			   char *buffer)
803 {
804 	struct INFTLrecord *inftl = (void *)mbd;
805 	unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
806 	unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
807         unsigned int status;
808 	int silly = MAX_LOOPS;
809         struct inftl_bci bci;
810 	size_t retlen;
811 
812 	DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
813 		"buffer=%p)\n", inftl, block, buffer);
814 
815 	while (thisEUN < inftl->nb_blocks) {
816 		if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize) +
817 		     blockofs, 8, &retlen, (char *)&bci) < 0)
818 			status = SECTOR_IGNORE;
819 		else
820 			status = bci.Status | bci.Status1;
821 
822 		switch (status) {
823 		case SECTOR_DELETED:
824 			thisEUN = BLOCK_NIL;
825 			goto foundit;
826 		case SECTOR_USED:
827 			goto foundit;
828 		case SECTOR_FREE:
829 		case SECTOR_IGNORE:
830 			break;
831 		default:
832 			printk(KERN_WARNING "INFTL: unknown status for "
833 				"block %ld in EUN %d: 0x%04x\n",
834 				block, thisEUN, status);
835 			break;
836 		}
837 
838 		if (!silly--) {
839 			printk(KERN_WARNING "INFTL: infinite loop in "
840 				"Virtual Unit Chain 0x%lx\n",
841 				block / (inftl->EraseSize / SECTORSIZE));
842 			return 1;
843 		}
844 
845 		thisEUN = inftl->PUtable[thisEUN];
846 	}
847 
848 foundit:
849 	if (thisEUN == BLOCK_NIL) {
850 		/* The requested block is not on the media, return all 0x00 */
851 		memset(buffer, 0, SECTORSIZE);
852 	} else {
853         	size_t retlen;
854 		loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
855 		if (MTD_READ(inftl->mbd.mtd, ptr, SECTORSIZE, &retlen,
856 		    buffer))
857 			return -EIO;
858 	}
859 	return 0;
860 }
861 
862 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
863 {
864 	struct INFTLrecord *inftl = (void *)dev;
865 
866 	geo->heads = inftl->heads;
867 	geo->sectors = inftl->sectors;
868 	geo->cylinders = inftl->cylinders;
869 
870 	return 0;
871 }
872 
873 static struct mtd_blktrans_ops inftl_tr = {
874 	.name		= "inftl",
875 	.major		= INFTL_MAJOR,
876 	.part_bits	= INFTL_PARTN_BITS,
877 	.getgeo		= inftl_getgeo,
878 	.readsect	= inftl_readblock,
879 	.writesect	= inftl_writeblock,
880 	.add_mtd	= inftl_add_mtd,
881 	.remove_dev	= inftl_remove_dev,
882 	.owner		= THIS_MODULE,
883 };
884 
885 static int __init init_inftl(void)
886 {
887 	printk(KERN_INFO "INFTL: inftlcore.c $Revision: 1.19 $, "
888 		"inftlmount.c %s\n", inftlmountrev);
889 
890 	return register_mtd_blktrans(&inftl_tr);
891 }
892 
893 static void __exit cleanup_inftl(void)
894 {
895 	deregister_mtd_blktrans(&inftl_tr);
896 }
897 
898 module_init(init_inftl);
899 module_exit(cleanup_inftl);
900 
901 MODULE_LICENSE("GPL");
902 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
903 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");
904