Merge branch 'x86/core' into x86/xsave
[linux-2.6] / drivers / mtd / inftlcore.c
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  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23  */
24
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/delay.h>
28 #include <linux/slab.h>
29 #include <linux/sched.h>
30 #include <linux/init.h>
31 #include <linux/kmod.h>
32 #include <linux/hdreg.h>
33 #include <linux/mtd/mtd.h>
34 #include <linux/mtd/nftl.h>
35 #include <linux/mtd/inftl.h>
36 #include <linux/mtd/nand.h>
37 #include <asm/uaccess.h>
38 #include <asm/errno.h>
39 #include <asm/io.h>
40
41 /*
42  * Maximum number of loops while examining next block, to have a
43  * chance to detect consistency problems (they should never happen
44  * because of the checks done in the mounting.
45  */
46 #define MAX_LOOPS 10000
47
48 static void inftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
49 {
50         struct INFTLrecord *inftl;
51         unsigned long temp;
52
53         if (mtd->type != MTD_NANDFLASH)
54                 return;
55         /* OK, this is moderately ugly.  But probably safe.  Alternatives? */
56         if (memcmp(mtd->name, "DiskOnChip", 10))
57                 return;
58
59         if (!mtd->block_isbad) {
60                 printk(KERN_ERR
61 "INFTL no longer supports the old DiskOnChip drivers loaded via docprobe.\n"
62 "Please use the new diskonchip driver under the NAND subsystem.\n");
63                 return;
64         }
65
66         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: add_mtd for %s\n", mtd->name);
67
68         inftl = kzalloc(sizeof(*inftl), GFP_KERNEL);
69
70         if (!inftl) {
71                 printk(KERN_WARNING "INFTL: Out of memory for data structures\n");
72                 return;
73         }
74
75         inftl->mbd.mtd = mtd;
76         inftl->mbd.devnum = -1;
77
78         inftl->mbd.tr = tr;
79
80         if (INFTL_mount(inftl) < 0) {
81                 printk(KERN_WARNING "INFTL: could not mount device\n");
82                 kfree(inftl);
83                 return;
84         }
85
86         /* OK, it's a new one. Set up all the data structures. */
87
88         /* Calculate geometry */
89         inftl->cylinders = 1024;
90         inftl->heads = 16;
91
92         temp = inftl->cylinders * inftl->heads;
93         inftl->sectors = inftl->mbd.size / temp;
94         if (inftl->mbd.size % temp) {
95                 inftl->sectors++;
96                 temp = inftl->cylinders * inftl->sectors;
97                 inftl->heads = inftl->mbd.size / temp;
98
99                 if (inftl->mbd.size % temp) {
100                         inftl->heads++;
101                         temp = inftl->heads * inftl->sectors;
102                         inftl->cylinders = inftl->mbd.size / temp;
103                 }
104         }
105
106         if (inftl->mbd.size != inftl->heads * inftl->cylinders * inftl->sectors) {
107                 /*
108                   Oh no we don't have
109                    mbd.size == heads * cylinders * sectors
110                 */
111                 printk(KERN_WARNING "INFTL: cannot calculate a geometry to "
112                        "match size of 0x%lx.\n", inftl->mbd.size);
113                 printk(KERN_WARNING "INFTL: using C:%d H:%d S:%d "
114                         "(== 0x%lx sects)\n",
115                         inftl->cylinders, inftl->heads , inftl->sectors,
116                         (long)inftl->cylinders * (long)inftl->heads *
117                         (long)inftl->sectors );
118         }
119
120         if (add_mtd_blktrans_dev(&inftl->mbd)) {
121                 kfree(inftl->PUtable);
122                 kfree(inftl->VUtable);
123                 kfree(inftl);
124                 return;
125         }
126 #ifdef PSYCHO_DEBUG
127         printk(KERN_INFO "INFTL: Found new inftl%c\n", inftl->mbd.devnum + 'a');
128 #endif
129         return;
130 }
131
132 static void inftl_remove_dev(struct mtd_blktrans_dev *dev)
133 {
134         struct INFTLrecord *inftl = (void *)dev;
135
136         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: remove_dev (i=%d)\n", dev->devnum);
137
138         del_mtd_blktrans_dev(dev);
139
140         kfree(inftl->PUtable);
141         kfree(inftl->VUtable);
142         kfree(inftl);
143 }
144
145 /*
146  * Actual INFTL access routines.
147  */
148
149 /*
150  * Read oob data from flash
151  */
152 int inftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
153                    size_t *retlen, uint8_t *buf)
154 {
155         struct mtd_oob_ops ops;
156         int res;
157
158         ops.mode = MTD_OOB_PLACE;
159         ops.ooboffs = offs & (mtd->writesize - 1);
160         ops.ooblen = len;
161         ops.oobbuf = buf;
162         ops.datbuf = NULL;
163
164         res = mtd->read_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
165         *retlen = ops.oobretlen;
166         return res;
167 }
168
169 /*
170  * Write oob data to flash
171  */
172 int inftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
173                     size_t *retlen, uint8_t *buf)
174 {
175         struct mtd_oob_ops ops;
176         int res;
177
178         ops.mode = MTD_OOB_PLACE;
179         ops.ooboffs = offs & (mtd->writesize - 1);
180         ops.ooblen = len;
181         ops.oobbuf = buf;
182         ops.datbuf = NULL;
183
184         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
185         *retlen = ops.oobretlen;
186         return res;
187 }
188
189 /*
190  * Write data and oob to flash
191  */
192 static int inftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
193                        size_t *retlen, uint8_t *buf, uint8_t *oob)
194 {
195         struct mtd_oob_ops ops;
196         int res;
197
198         ops.mode = MTD_OOB_PLACE;
199         ops.ooboffs = offs;
200         ops.ooblen = mtd->oobsize;
201         ops.oobbuf = oob;
202         ops.datbuf = buf;
203         ops.len = len;
204
205         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
206         *retlen = ops.retlen;
207         return res;
208 }
209
210 /*
211  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
212  *      This function is used when the give Virtual Unit Chain.
213  */
214 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
215 {
216         u16 pot = inftl->LastFreeEUN;
217         int silly = inftl->nb_blocks;
218
219         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
220                 "desperate=%d)\n", inftl, desperate);
221
222         /*
223          * Normally, we force a fold to happen before we run out of free
224          * blocks completely.
225          */
226         if (!desperate && inftl->numfreeEUNs < 2) {
227                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
228                         "EUNs (%d)\n", inftl->numfreeEUNs);
229                 return 0xffff;
230         }
231
232         /* Scan for a free block */
233         do {
234                 if (inftl->PUtable[pot] == BLOCK_FREE) {
235                         inftl->LastFreeEUN = pot;
236                         return pot;
237                 }
238
239                 if (++pot > inftl->lastEUN)
240                         pot = 0;
241
242                 if (!silly--) {
243                         printk(KERN_WARNING "INFTL: no free blocks found!  "
244                                 "EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
245                         return BLOCK_NIL;
246                 }
247         } while (pot != inftl->LastFreeEUN);
248
249         return BLOCK_NIL;
250 }
251
252 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
253 {
254         u16 BlockMap[MAX_SECTORS_PER_UNIT];
255         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
256         unsigned int thisEUN, prevEUN, status;
257         struct mtd_info *mtd = inftl->mbd.mtd;
258         int block, silly;
259         unsigned int targetEUN;
260         struct inftl_oob oob;
261         size_t retlen;
262
263         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
264                 "pending=%d)\n", inftl, thisVUC, pendingblock);
265
266         memset(BlockMap, 0xff, sizeof(BlockMap));
267         memset(BlockDeleted, 0, sizeof(BlockDeleted));
268
269         thisEUN = targetEUN = inftl->VUtable[thisVUC];
270
271         if (thisEUN == BLOCK_NIL) {
272                 printk(KERN_WARNING "INFTL: trying to fold non-existent "
273                        "Virtual Unit Chain %d!\n", thisVUC);
274                 return BLOCK_NIL;
275         }
276
277         /*
278          * Scan to find the Erase Unit which holds the actual data for each
279          * 512-byte block within the Chain.
280          */
281         silly = MAX_LOOPS;
282         while (thisEUN < inftl->nb_blocks) {
283                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
284                         if ((BlockMap[block] != 0xffff) || BlockDeleted[block])
285                                 continue;
286
287                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
288                                            + (block * SECTORSIZE), 16, &retlen,
289                                            (char *)&oob) < 0)
290                                 status = SECTOR_IGNORE;
291                         else
292                                 status = oob.b.Status | oob.b.Status1;
293
294                         switch(status) {
295                         case SECTOR_FREE:
296                         case SECTOR_IGNORE:
297                                 break;
298                         case SECTOR_USED:
299                                 BlockMap[block] = thisEUN;
300                                 continue;
301                         case SECTOR_DELETED:
302                                 BlockDeleted[block] = 1;
303                                 continue;
304                         default:
305                                 printk(KERN_WARNING "INFTL: unknown status "
306                                         "for block %d in EUN %d: %x\n",
307                                         block, thisEUN, status);
308                                 break;
309                         }
310                 }
311
312                 if (!silly--) {
313                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
314                                 "Unit Chain 0x%x\n", thisVUC);
315                         return BLOCK_NIL;
316                 }
317
318                 thisEUN = inftl->PUtable[thisEUN];
319         }
320
321         /*
322          * OK. We now know the location of every block in the Virtual Unit
323          * Chain, and the Erase Unit into which we are supposed to be copying.
324          * Go for it.
325          */
326         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: folding chain %d into unit %d\n",
327                 thisVUC, targetEUN);
328
329         for (block = 0; block < inftl->EraseSize/SECTORSIZE ; block++) {
330                 unsigned char movebuf[SECTORSIZE];
331                 int ret;
332
333                 /*
334                  * If it's in the target EUN already, or if it's pending write,
335                  * do nothing.
336                  */
337                 if (BlockMap[block] == targetEUN || (pendingblock ==
338                     (thisVUC * (inftl->EraseSize / SECTORSIZE) + block))) {
339                         continue;
340                 }
341
342                 /*
343                  * Copy only in non free block (free blocks can only
344                  * happen in case of media errors or deleted blocks).
345                  */
346                 if (BlockMap[block] == BLOCK_NIL)
347                         continue;
348
349                 ret = mtd->read(mtd, (inftl->EraseSize * BlockMap[block]) +
350                                 (block * SECTORSIZE), SECTORSIZE, &retlen,
351                                 movebuf);
352                 if (ret < 0 && ret != -EUCLEAN) {
353                         ret = mtd->read(mtd,
354                                         (inftl->EraseSize * BlockMap[block]) +
355                                         (block * SECTORSIZE), SECTORSIZE,
356                                         &retlen, movebuf);
357                         if (ret != -EIO)
358                                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: error went "
359                                       "away on retry?\n");
360                 }
361                 memset(&oob, 0xff, sizeof(struct inftl_oob));
362                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
363
364                 inftl_write(inftl->mbd.mtd, (inftl->EraseSize * targetEUN) +
365                             (block * SECTORSIZE), SECTORSIZE, &retlen,
366                             movebuf, (char *)&oob);
367         }
368
369         /*
370          * Newest unit in chain now contains data from _all_ older units.
371          * So go through and erase each unit in chain, oldest first. (This
372          * is important, by doing oldest first if we crash/reboot then it
373          * it is relatively simple to clean up the mess).
374          */
375         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: want to erase virtual chain %d\n",
376                 thisVUC);
377
378         for (;;) {
379                 /* Find oldest unit in chain. */
380                 thisEUN = inftl->VUtable[thisVUC];
381                 prevEUN = BLOCK_NIL;
382                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
383                         prevEUN = thisEUN;
384                         thisEUN = inftl->PUtable[thisEUN];
385                 }
386
387                 /* Check if we are all done */
388                 if (thisEUN == targetEUN)
389                         break;
390
391                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
392                         /*
393                          * Could not erase : mark block as reserved.
394                          */
395                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
396                 } else {
397                         /* Correctly erased : mark it as free */
398                         inftl->PUtable[thisEUN] = BLOCK_FREE;
399                         inftl->PUtable[prevEUN] = BLOCK_NIL;
400                         inftl->numfreeEUNs++;
401                 }
402         }
403
404         return targetEUN;
405 }
406
407 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
408 {
409         /*
410          * This is the part that needs some cleverness applied.
411          * For now, I'm doing the minimum applicable to actually
412          * get the thing to work.
413          * Wear-levelling and other clever stuff needs to be implemented
414          * and we also need to do some assessment of the results when
415          * the system loses power half-way through the routine.
416          */
417         u16 LongestChain = 0;
418         u16 ChainLength = 0, thislen;
419         u16 chain, EUN;
420
421         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
422                 "pending=%d)\n", inftl, pendingblock);
423
424         for (chain = 0; chain < inftl->nb_blocks; chain++) {
425                 EUN = inftl->VUtable[chain];
426                 thislen = 0;
427
428                 while (EUN <= inftl->lastEUN) {
429                         thislen++;
430                         EUN = inftl->PUtable[EUN];
431                         if (thislen > 0xff00) {
432                                 printk(KERN_WARNING "INFTL: endless loop in "
433                                         "Virtual Chain %d: Unit %x\n",
434                                         chain, EUN);
435                                 /*
436                                  * Actually, don't return failure.
437                                  * Just ignore this chain and get on with it.
438                                  */
439                                 thislen = 0;
440                                 break;
441                         }
442                 }
443
444                 if (thislen > ChainLength) {
445                         ChainLength = thislen;
446                         LongestChain = chain;
447                 }
448         }
449
450         if (ChainLength < 2) {
451                 printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
452                         "for folding. Failing request\n");
453                 return BLOCK_NIL;
454         }
455
456         return INFTL_foldchain(inftl, LongestChain, pendingblock);
457 }
458
459 static int nrbits(unsigned int val, int bitcount)
460 {
461         int i, total = 0;
462
463         for (i = 0; (i < bitcount); i++)
464                 total += (((0x1 << i) & val) ? 1 : 0);
465         return total;
466 }
467
468 /*
469  * INFTL_findwriteunit: Return the unit number into which we can write
470  *                      for this block. Make it available if it isn't already.
471  */
472 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
473 {
474         unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
475         unsigned int thisEUN, writeEUN, prev_block, status;
476         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
477         struct mtd_info *mtd = inftl->mbd.mtd;
478         struct inftl_oob oob;
479         struct inftl_bci bci;
480         unsigned char anac, nacs, parity;
481         size_t retlen;
482         int silly, silly2 = 3;
483
484         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findwriteunit(inftl=%p,"
485                 "block=%d)\n", inftl, block);
486
487         do {
488                 /*
489                  * Scan the media to find a unit in the VUC which has
490                  * a free space for the block in question.
491                  */
492                 writeEUN = BLOCK_NIL;
493                 thisEUN = inftl->VUtable[thisVUC];
494                 silly = MAX_LOOPS;
495
496                 while (thisEUN <= inftl->lastEUN) {
497                         inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
498                                        blockofs, 8, &retlen, (char *)&bci);
499
500                         status = bci.Status | bci.Status1;
501                         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: status of block %d in "
502                                 "EUN %d is %x\n", block , writeEUN, status);
503
504                         switch(status) {
505                         case SECTOR_FREE:
506                                 writeEUN = thisEUN;
507                                 break;
508                         case SECTOR_DELETED:
509                         case SECTOR_USED:
510                                 /* Can't go any further */
511                                 goto hitused;
512                         case SECTOR_IGNORE:
513                                 break;
514                         default:
515                                 /*
516                                  * Invalid block. Don't use it any more.
517                                  * Must implement.
518                                  */
519                                 break;
520                         }
521
522                         if (!silly--) {
523                                 printk(KERN_WARNING "INFTL: infinite loop in "
524                                         "Virtual Unit Chain 0x%x\n", thisVUC);
525                                 return 0xffff;
526                         }
527
528                         /* Skip to next block in chain */
529                         thisEUN = inftl->PUtable[thisEUN];
530                 }
531
532 hitused:
533                 if (writeEUN != BLOCK_NIL)
534                         return writeEUN;
535
536
537                 /*
538                  * OK. We didn't find one in the existing chain, or there
539                  * is no existing chain. Allocate a new one.
540                  */
541                 writeEUN = INFTL_findfreeblock(inftl, 0);
542
543                 if (writeEUN == BLOCK_NIL) {
544                         /*
545                          * That didn't work - there were no free blocks just
546                          * waiting to be picked up. We're going to have to fold
547                          * a chain to make room.
548                          */
549                         thisEUN = INFTL_makefreeblock(inftl, 0xffff);
550
551                         /*
552                          * Hopefully we free something, lets try again.
553                          * This time we are desperate...
554                          */
555                         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: using desperate==1 "
556                                 "to find free EUN to accommodate write to "
557                                 "VUC %d\n", thisVUC);
558                         writeEUN = INFTL_findfreeblock(inftl, 1);
559                         if (writeEUN == BLOCK_NIL) {
560                                 /*
561                                  * Ouch. This should never happen - we should
562                                  * always be able to make some room somehow.
563                                  * If we get here, we've allocated more storage
564                                  * space than actual media, or our makefreeblock
565                                  * routine is missing something.
566                                  */
567                                 printk(KERN_WARNING "INFTL: cannot make free "
568                                         "space.\n");
569 #ifdef DEBUG
570                                 INFTL_dumptables(inftl);
571                                 INFTL_dumpVUchains(inftl);
572 #endif
573                                 return BLOCK_NIL;
574                         }
575                 }
576
577                 /*
578                  * Insert new block into virtual chain. Firstly update the
579                  * block headers in flash...
580                  */
581                 anac = 0;
582                 nacs = 0;
583                 thisEUN = inftl->VUtable[thisVUC];
584                 if (thisEUN != BLOCK_NIL) {
585                         inftl_read_oob(mtd, thisEUN * inftl->EraseSize
586                                        + 8, 8, &retlen, (char *)&oob.u);
587                         anac = oob.u.a.ANAC + 1;
588                         nacs = oob.u.a.NACs + 1;
589                 }
590
591                 prev_block = inftl->VUtable[thisVUC];
592                 if (prev_block < inftl->nb_blocks)
593                         prev_block -= inftl->firstEUN;
594
595                 parity = (nrbits(thisVUC, 16) & 0x1) ? 0x1 : 0;
596                 parity |= (nrbits(prev_block, 16) & 0x1) ? 0x2 : 0;
597                 parity |= (nrbits(anac, 8) & 0x1) ? 0x4 : 0;
598                 parity |= (nrbits(nacs, 8) & 0x1) ? 0x8 : 0;
599
600                 oob.u.a.virtualUnitNo = cpu_to_le16(thisVUC);
601                 oob.u.a.prevUnitNo = cpu_to_le16(prev_block);
602                 oob.u.a.ANAC = anac;
603                 oob.u.a.NACs = nacs;
604                 oob.u.a.parityPerField = parity;
605                 oob.u.a.discarded = 0xaa;
606
607                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize + 8, 8,
608                                 &retlen, (char *)&oob.u);
609
610                 /* Also back up header... */
611                 oob.u.b.virtualUnitNo = cpu_to_le16(thisVUC);
612                 oob.u.b.prevUnitNo = cpu_to_le16(prev_block);
613                 oob.u.b.ANAC = anac;
614                 oob.u.b.NACs = nacs;
615                 oob.u.b.parityPerField = parity;
616                 oob.u.b.discarded = 0xaa;
617
618                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize +
619                                 SECTORSIZE * 4 + 8, 8, &retlen, (char *)&oob.u);
620
621                 inftl->PUtable[writeEUN] = inftl->VUtable[thisVUC];
622                 inftl->VUtable[thisVUC] = writeEUN;
623
624                 inftl->numfreeEUNs--;
625                 return writeEUN;
626
627         } while (silly2--);
628
629         printk(KERN_WARNING "INFTL: error folding to make room for Virtual "
630                 "Unit Chain 0x%x\n", thisVUC);
631         return 0xffff;
632 }
633
634 /*
635  * Given a Virtual Unit Chain, see if it can be deleted, and if so do it.
636  */
637 static void INFTL_trydeletechain(struct INFTLrecord *inftl, unsigned thisVUC)
638 {
639         struct mtd_info *mtd = inftl->mbd.mtd;
640         unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
641         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
642         unsigned int thisEUN, status;
643         int block, silly;
644         struct inftl_bci bci;
645         size_t retlen;
646
647         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
648                 "thisVUC=%d)\n", inftl, thisVUC);
649
650         memset(BlockUsed, 0, sizeof(BlockUsed));
651         memset(BlockDeleted, 0, sizeof(BlockDeleted));
652
653         thisEUN = inftl->VUtable[thisVUC];
654         if (thisEUN == BLOCK_NIL) {
655                 printk(KERN_WARNING "INFTL: trying to delete non-existent "
656                        "Virtual Unit Chain %d!\n", thisVUC);
657                 return;
658         }
659
660         /*
661          * Scan through the Erase Units to determine whether any data is in
662          * each of the 512-byte blocks within the Chain.
663          */
664         silly = MAX_LOOPS;
665         while (thisEUN < inftl->nb_blocks) {
666                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
667                         if (BlockUsed[block] || BlockDeleted[block])
668                                 continue;
669
670                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
671                                            + (block * SECTORSIZE), 8 , &retlen,
672                                           (char *)&bci) < 0)
673                                 status = SECTOR_IGNORE;
674                         else
675                                 status = bci.Status | bci.Status1;
676
677                         switch(status) {
678                         case SECTOR_FREE:
679                         case SECTOR_IGNORE:
680                                 break;
681                         case SECTOR_USED:
682                                 BlockUsed[block] = 1;
683                                 continue;
684                         case SECTOR_DELETED:
685                                 BlockDeleted[block] = 1;
686                                 continue;
687                         default:
688                                 printk(KERN_WARNING "INFTL: unknown status "
689                                         "for block %d in EUN %d: 0x%x\n",
690                                         block, thisEUN, status);
691                         }
692                 }
693
694                 if (!silly--) {
695                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
696                                 "Unit Chain 0x%x\n", thisVUC);
697                         return;
698                 }
699
700                 thisEUN = inftl->PUtable[thisEUN];
701         }
702
703         for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
704                 if (BlockUsed[block])
705                         return;
706
707         /*
708          * For each block in the chain free it and make it available
709          * for future use. Erase from the oldest unit first.
710          */
711         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
712
713         for (;;) {
714                 u16 *prevEUN = &inftl->VUtable[thisVUC];
715                 thisEUN = *prevEUN;
716
717                 /* If the chain is all gone already, we're done */
718                 if (thisEUN == BLOCK_NIL) {
719                         DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
720                         return;
721                 }
722
723                 /* Find oldest unit in chain. */
724                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
725                         BUG_ON(thisEUN >= inftl->nb_blocks);
726
727                         prevEUN = &inftl->PUtable[thisEUN];
728                         thisEUN = *prevEUN;
729                 }
730
731                 DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
732                       thisEUN, thisVUC);
733
734                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
735                         /*
736                          * Could not erase : mark block as reserved.
737                          */
738                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
739                 } else {
740                         /* Correctly erased : mark it as free */
741                         inftl->PUtable[thisEUN] = BLOCK_FREE;
742                         inftl->numfreeEUNs++;
743                 }
744
745                 /* Now sort out whatever was pointing to it... */
746                 *prevEUN = BLOCK_NIL;
747
748                 /* Ideally we'd actually be responsive to new
749                    requests while we're doing this -- if there's
750                    free space why should others be made to wait? */
751                 cond_resched();
752         }
753
754         inftl->VUtable[thisVUC] = BLOCK_NIL;
755 }
756
757 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
758 {
759         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
760         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
761         struct mtd_info *mtd = inftl->mbd.mtd;
762         unsigned int status;
763         int silly = MAX_LOOPS;
764         size_t retlen;
765         struct inftl_bci bci;
766
767         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
768                 "block=%d)\n", inftl, block);
769
770         while (thisEUN < inftl->nb_blocks) {
771                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
772                                    blockofs, 8, &retlen, (char *)&bci) < 0)
773                         status = SECTOR_IGNORE;
774                 else
775                         status = bci.Status | bci.Status1;
776
777                 switch (status) {
778                 case SECTOR_FREE:
779                 case SECTOR_IGNORE:
780                         break;
781                 case SECTOR_DELETED:
782                         thisEUN = BLOCK_NIL;
783                         goto foundit;
784                 case SECTOR_USED:
785                         goto foundit;
786                 default:
787                         printk(KERN_WARNING "INFTL: unknown status for "
788                                 "block %d in EUN %d: 0x%x\n",
789                                 block, thisEUN, status);
790                         break;
791                 }
792
793                 if (!silly--) {
794                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
795                                 "Unit Chain 0x%x\n",
796                                 block / (inftl->EraseSize / SECTORSIZE));
797                         return 1;
798                 }
799                 thisEUN = inftl->PUtable[thisEUN];
800         }
801
802 foundit:
803         if (thisEUN != BLOCK_NIL) {
804                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
805
806                 if (inftl_read_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
807                         return -EIO;
808                 bci.Status = bci.Status1 = SECTOR_DELETED;
809                 if (inftl_write_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
810                         return -EIO;
811                 INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
812         }
813         return 0;
814 }
815
816 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
817                             char *buffer)
818 {
819         struct INFTLrecord *inftl = (void *)mbd;
820         unsigned int writeEUN;
821         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
822         size_t retlen;
823         struct inftl_oob oob;
824         char *p, *pend;
825
826         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
827                 "buffer=%p)\n", inftl, block, buffer);
828
829         /* Is block all zero? */
830         pend = buffer + SECTORSIZE;
831         for (p = buffer; p < pend && !*p; p++)
832                 ;
833
834         if (p < pend) {
835                 writeEUN = INFTL_findwriteunit(inftl, block);
836
837                 if (writeEUN == BLOCK_NIL) {
838                         printk(KERN_WARNING "inftl_writeblock(): cannot find "
839                                 "block to write to\n");
840                         /*
841                          * If we _still_ haven't got a block to use,
842                          * we're screwed.
843                          */
844                         return 1;
845                 }
846
847                 memset(&oob, 0xff, sizeof(struct inftl_oob));
848                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
849
850                 inftl_write(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
851                             blockofs, SECTORSIZE, &retlen, (char *)buffer,
852                             (char *)&oob);
853                 /*
854                  * need to write SECTOR_USED flags since they are not written
855                  * in mtd_writeecc
856                  */
857         } else {
858                 INFTL_deleteblock(inftl, block);
859         }
860
861         return 0;
862 }
863
864 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
865                            char *buffer)
866 {
867         struct INFTLrecord *inftl = (void *)mbd;
868         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
869         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
870         struct mtd_info *mtd = inftl->mbd.mtd;
871         unsigned int status;
872         int silly = MAX_LOOPS;
873         struct inftl_bci bci;
874         size_t retlen;
875
876         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
877                 "buffer=%p)\n", inftl, block, buffer);
878
879         while (thisEUN < inftl->nb_blocks) {
880                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
881                                   blockofs, 8, &retlen, (char *)&bci) < 0)
882                         status = SECTOR_IGNORE;
883                 else
884                         status = bci.Status | bci.Status1;
885
886                 switch (status) {
887                 case SECTOR_DELETED:
888                         thisEUN = BLOCK_NIL;
889                         goto foundit;
890                 case SECTOR_USED:
891                         goto foundit;
892                 case SECTOR_FREE:
893                 case SECTOR_IGNORE:
894                         break;
895                 default:
896                         printk(KERN_WARNING "INFTL: unknown status for "
897                                 "block %ld in EUN %d: 0x%04x\n",
898                                 block, thisEUN, status);
899                         break;
900                 }
901
902                 if (!silly--) {
903                         printk(KERN_WARNING "INFTL: infinite loop in "
904                                 "Virtual Unit Chain 0x%lx\n",
905                                 block / (inftl->EraseSize / SECTORSIZE));
906                         return 1;
907                 }
908
909                 thisEUN = inftl->PUtable[thisEUN];
910         }
911
912 foundit:
913         if (thisEUN == BLOCK_NIL) {
914                 /* The requested block is not on the media, return all 0x00 */
915                 memset(buffer, 0, SECTORSIZE);
916         } else {
917                 size_t retlen;
918                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
919                 int ret = mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer);
920
921                 /* Handle corrected bit flips gracefully */
922                 if (ret < 0 && ret != -EUCLEAN)
923                         return -EIO;
924         }
925         return 0;
926 }
927
928 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
929 {
930         struct INFTLrecord *inftl = (void *)dev;
931
932         geo->heads = inftl->heads;
933         geo->sectors = inftl->sectors;
934         geo->cylinders = inftl->cylinders;
935
936         return 0;
937 }
938
939 static struct mtd_blktrans_ops inftl_tr = {
940         .name           = "inftl",
941         .major          = INFTL_MAJOR,
942         .part_bits      = INFTL_PARTN_BITS,
943         .blksize        = 512,
944         .getgeo         = inftl_getgeo,
945         .readsect       = inftl_readblock,
946         .writesect      = inftl_writeblock,
947         .add_mtd        = inftl_add_mtd,
948         .remove_dev     = inftl_remove_dev,
949         .owner          = THIS_MODULE,
950 };
951
952 static int __init init_inftl(void)
953 {
954         return register_mtd_blktrans(&inftl_tr);
955 }
956
957 static void __exit cleanup_inftl(void)
958 {
959         deregister_mtd_blktrans(&inftl_tr);
960 }
961
962 module_init(init_inftl);
963 module_exit(cleanup_inftl);
964
965 MODULE_LICENSE("GPL");
966 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
967 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");