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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Linux driver for NAND Flash Translation Layer
4 *
5 * Copyright © 1999 Machine Vision Holdings, Inc.
6 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
7 */
8
9#define PRERELEASE
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <asm/errno.h>
14#include <asm/io.h>
15#include <linux/uaccess.h>
16#include <linux/delay.h>
17#include <linux/slab.h>
18#include <linux/init.h>
19#include <linux/hdreg.h>
20#include <linux/blkdev.h>
21
22#include <linux/kmod.h>
23#include <linux/mtd/mtd.h>
24#include <linux/mtd/rawnand.h>
25#include <linux/mtd/nftl.h>
26#include <linux/mtd/blktrans.h>
27
28/* maximum number of loops while examining next block, to have a
29 chance to detect consistency problems (they should never happen
30 because of the checks done in the mounting */
31
32#define MAX_LOOPS 10000
33
34
35static void nftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
36{
37 struct NFTLrecord *nftl;
38 unsigned long temp;
39
40 if (!mtd_type_is_nand(mtd) || mtd->size > UINT_MAX)
41 return;
42 /* OK, this is moderately ugly. But probably safe. Alternatives? */
43 if (memcmp(mtd->name, "DiskOnChip", 10))
44 return;
45
46 pr_debug("NFTL: add_mtd for %s\n", mtd->name);
47
48 nftl = kzalloc(sizeof(struct NFTLrecord), GFP_KERNEL);
49
50 if (!nftl)
51 return;
52
53 nftl->mbd.mtd = mtd;
54 nftl->mbd.devnum = -1;
55
56 nftl->mbd.tr = tr;
57
58 if (NFTL_mount(nftl) < 0) {
59 printk(KERN_WARNING "NFTL: could not mount device\n");
60 kfree(nftl);
61 return;
62 }
63
64 /* OK, it's a new one. Set up all the data structures. */
65
66 /* Calculate geometry */
67 nftl->cylinders = 1024;
68 nftl->heads = 16;
69
70 temp = nftl->cylinders * nftl->heads;
71 nftl->sectors = nftl->mbd.size / temp;
72 if (nftl->mbd.size % temp) {
73 nftl->sectors++;
74 temp = nftl->cylinders * nftl->sectors;
75 nftl->heads = nftl->mbd.size / temp;
76
77 if (nftl->mbd.size % temp) {
78 nftl->heads++;
79 temp = nftl->heads * nftl->sectors;
80 nftl->cylinders = nftl->mbd.size / temp;
81 }
82 }
83
84 if (nftl->mbd.size != nftl->heads * nftl->cylinders * nftl->sectors) {
85 /*
86 Oh no we don't have
87 mbd.size == heads * cylinders * sectors
88 */
89 printk(KERN_WARNING "NFTL: cannot calculate a geometry to "
90 "match size of 0x%lx.\n", nftl->mbd.size);
91 printk(KERN_WARNING "NFTL: using C:%d H:%d S:%d "
92 "(== 0x%lx sects)\n",
93 nftl->cylinders, nftl->heads , nftl->sectors,
94 (long)nftl->cylinders * (long)nftl->heads *
95 (long)nftl->sectors );
96 }
97
98 if (add_mtd_blktrans_dev(&nftl->mbd)) {
99 kfree(nftl->ReplUnitTable);
100 kfree(nftl->EUNtable);
101 kfree(nftl);
102 return;
103 }
104#ifdef PSYCHO_DEBUG
105 printk(KERN_INFO "NFTL: Found new nftl%c\n", nftl->mbd.devnum + 'a');
106#endif
107}
108
109static void nftl_remove_dev(struct mtd_blktrans_dev *dev)
110{
111 struct NFTLrecord *nftl = (void *)dev;
112
113 pr_debug("NFTL: remove_dev (i=%d)\n", dev->devnum);
114
115 del_mtd_blktrans_dev(dev);
116 kfree(nftl->ReplUnitTable);
117 kfree(nftl->EUNtable);
118}
119
120/*
121 * Read oob data from flash
122 */
123int nftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
124 size_t *retlen, uint8_t *buf)
125{
126 loff_t mask = mtd->writesize - 1;
127 struct mtd_oob_ops ops = { };
128 int res;
129
130 ops.mode = MTD_OPS_PLACE_OOB;
131 ops.ooboffs = offs & mask;
132 ops.ooblen = len;
133 ops.oobbuf = buf;
134 ops.datbuf = NULL;
135
136 res = mtd_read_oob(mtd, offs & ~mask, &ops);
137 *retlen = ops.oobretlen;
138 return res;
139}
140
141/*
142 * Write oob data to flash
143 */
144int nftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
145 size_t *retlen, uint8_t *buf)
146{
147 loff_t mask = mtd->writesize - 1;
148 struct mtd_oob_ops ops = { };
149 int res;
150
151 ops.mode = MTD_OPS_PLACE_OOB;
152 ops.ooboffs = offs & mask;
153 ops.ooblen = len;
154 ops.oobbuf = buf;
155 ops.datbuf = NULL;
156
157 res = mtd_write_oob(mtd, offs & ~mask, &ops);
158 *retlen = ops.oobretlen;
159 return res;
160}
161
162#ifdef CONFIG_NFTL_RW
163
164/*
165 * Write data and oob to flash
166 */
167static int nftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
168 size_t *retlen, uint8_t *buf, uint8_t *oob)
169{
170 loff_t mask = mtd->writesize - 1;
171 struct mtd_oob_ops ops = { };
172 int res;
173
174 ops.mode = MTD_OPS_PLACE_OOB;
175 ops.ooboffs = offs & mask;
176 ops.ooblen = mtd->oobsize;
177 ops.oobbuf = oob;
178 ops.datbuf = buf;
179 ops.len = len;
180
181 res = mtd_write_oob(mtd, offs & ~mask, &ops);
182 *retlen = ops.retlen;
183 return res;
184}
185
186/* Actual NFTL access routines */
187/* NFTL_findfreeblock: Find a free Erase Unit on the NFTL partition. This function is used
188 * when the give Virtual Unit Chain
189 */
190static u16 NFTL_findfreeblock(struct NFTLrecord *nftl, int desperate )
191{
192 /* For a given Virtual Unit Chain: find or create a free block and
193 add it to the chain */
194 /* We're passed the number of the last EUN in the chain, to save us from
195 having to look it up again */
196 u16 pot = nftl->LastFreeEUN;
197 int silly = nftl->nb_blocks;
198
199 /* Normally, we force a fold to happen before we run out of free blocks completely */
200 if (!desperate && nftl->numfreeEUNs < 2) {
201 pr_debug("NFTL_findfreeblock: there are too few free EUNs\n");
202 return BLOCK_NIL;
203 }
204
205 /* Scan for a free block */
206 do {
207 if (nftl->ReplUnitTable[pot] == BLOCK_FREE) {
208 nftl->LastFreeEUN = pot;
209 nftl->numfreeEUNs--;
210 return pot;
211 }
212
213 /* This will probably point to the MediaHdr unit itself,
214 right at the beginning of the partition. But that unit
215 (and the backup unit too) should have the UCI set
216 up so that it's not selected for overwriting */
217 if (++pot > nftl->lastEUN)
218 pot = le16_to_cpu(nftl->MediaHdr.FirstPhysicalEUN);
219
220 if (!silly--) {
221 printk("Argh! No free blocks found! LastFreeEUN = %d, "
222 "FirstEUN = %d\n", nftl->LastFreeEUN,
223 le16_to_cpu(nftl->MediaHdr.FirstPhysicalEUN));
224 return BLOCK_NIL;
225 }
226 } while (pot != nftl->LastFreeEUN);
227
228 return BLOCK_NIL;
229}
230
231static u16 NFTL_foldchain (struct NFTLrecord *nftl, unsigned thisVUC, unsigned pendingblock )
232{
233 struct mtd_info *mtd = nftl->mbd.mtd;
234 u16 BlockMap[MAX_SECTORS_PER_UNIT];
235 unsigned char BlockLastState[MAX_SECTORS_PER_UNIT];
236 unsigned char BlockFreeFound[MAX_SECTORS_PER_UNIT];
237 unsigned int thisEUN;
238 int block;
239 int silly;
240 unsigned int targetEUN;
241 struct nftl_oob oob;
242 int inplace = 1;
243 size_t retlen;
244
245 memset(BlockMap, 0xff, sizeof(BlockMap));
246 memset(BlockFreeFound, 0, sizeof(BlockFreeFound));
247
248 thisEUN = nftl->EUNtable[thisVUC];
249
250 if (thisEUN == BLOCK_NIL) {
251 printk(KERN_WARNING "Trying to fold non-existent "
252 "Virtual Unit Chain %d!\n", thisVUC);
253 return BLOCK_NIL;
254 }
255
256 /* Scan to find the Erase Unit which holds the actual data for each
257 512-byte block within the Chain.
258 */
259 silly = MAX_LOOPS;
260 targetEUN = BLOCK_NIL;
261 while (thisEUN <= nftl->lastEUN ) {
262 unsigned int status, foldmark;
263
264 targetEUN = thisEUN;
265 for (block = 0; block < nftl->EraseSize / 512; block ++) {
266 nftl_read_oob(mtd, (thisEUN * nftl->EraseSize) +
267 (block * 512), 16 , &retlen,
268 (char *)&oob);
269 if (block == 2) {
270 foldmark = oob.u.c.FoldMark | oob.u.c.FoldMark1;
271 if (foldmark == FOLD_MARK_IN_PROGRESS) {
272 pr_debug("Write Inhibited on EUN %d\n", thisEUN);
273 inplace = 0;
274 } else {
275 /* There's no other reason not to do inplace,
276 except ones that come later. So we don't need
277 to preserve inplace */
278 inplace = 1;
279 }
280 }
281 status = oob.b.Status | oob.b.Status1;
282 BlockLastState[block] = status;
283
284 switch(status) {
285 case SECTOR_FREE:
286 BlockFreeFound[block] = 1;
287 break;
288
289 case SECTOR_USED:
290 if (!BlockFreeFound[block])
291 BlockMap[block] = thisEUN;
292 else
293 printk(KERN_WARNING
294 "SECTOR_USED found after SECTOR_FREE "
295 "in Virtual Unit Chain %d for block %d\n",
296 thisVUC, block);
297 break;
298 case SECTOR_DELETED:
299 if (!BlockFreeFound[block])
300 BlockMap[block] = BLOCK_NIL;
301 else
302 printk(KERN_WARNING
303 "SECTOR_DELETED found after SECTOR_FREE "
304 "in Virtual Unit Chain %d for block %d\n",
305 thisVUC, block);
306 break;
307
308 case SECTOR_IGNORE:
309 break;
310 default:
311 printk("Unknown status for block %d in EUN %d: %x\n",
312 block, thisEUN, status);
313 }
314 }
315
316 if (!silly--) {
317 printk(KERN_WARNING "Infinite loop in Virtual Unit Chain 0x%x\n",
318 thisVUC);
319 return BLOCK_NIL;
320 }
321
322 thisEUN = nftl->ReplUnitTable[thisEUN];
323 }
324
325 if (inplace) {
326 /* We're being asked to be a fold-in-place. Check
327 that all blocks which actually have data associated
328 with them (i.e. BlockMap[block] != BLOCK_NIL) are
329 either already present or SECTOR_FREE in the target
330 block. If not, we're going to have to fold out-of-place
331 anyway.
332 */
333 for (block = 0; block < nftl->EraseSize / 512 ; block++) {
334 if (BlockLastState[block] != SECTOR_FREE &&
335 BlockMap[block] != BLOCK_NIL &&
336 BlockMap[block] != targetEUN) {
337 pr_debug("Setting inplace to 0. VUC %d, "
338 "block %d was %x lastEUN, "
339 "and is in EUN %d (%s) %d\n",
340 thisVUC, block, BlockLastState[block],
341 BlockMap[block],
342 BlockMap[block]== targetEUN ? "==" : "!=",
343 targetEUN);
344 inplace = 0;
345 break;
346 }
347 }
348
349 if (pendingblock >= (thisVUC * (nftl->EraseSize / 512)) &&
350 pendingblock < ((thisVUC + 1)* (nftl->EraseSize / 512)) &&
351 BlockLastState[pendingblock - (thisVUC * (nftl->EraseSize / 512))] !=
352 SECTOR_FREE) {
353 pr_debug("Pending write not free in EUN %d. "
354 "Folding out of place.\n", targetEUN);
355 inplace = 0;
356 }
357 }
358
359 if (!inplace) {
360 pr_debug("Cannot fold Virtual Unit Chain %d in place. "
361 "Trying out-of-place\n", thisVUC);
362 /* We need to find a targetEUN to fold into. */
363 targetEUN = NFTL_findfreeblock(nftl, 1);
364 if (targetEUN == BLOCK_NIL) {
365 /* Ouch. Now we're screwed. We need to do a
366 fold-in-place of another chain to make room
367 for this one. We need a better way of selecting
368 which chain to fold, because makefreeblock will
369 only ask us to fold the same one again.
370 */
371 printk(KERN_WARNING
372 "NFTL_findfreeblock(desperate) returns 0xffff.\n");
373 return BLOCK_NIL;
374 }
375 } else {
376 /* We put a fold mark in the chain we are folding only if we
377 fold in place to help the mount check code. If we do not fold in
378 place, it is possible to find the valid chain by selecting the
379 longer one */
380 oob.u.c.FoldMark = oob.u.c.FoldMark1 = cpu_to_le16(FOLD_MARK_IN_PROGRESS);
381 oob.u.c.unused = 0xffffffff;
382 nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 2 * 512 + 8,
383 8, &retlen, (char *)&oob.u);
384 }
385
386 /* OK. We now know the location of every block in the Virtual Unit Chain,
387 and the Erase Unit into which we are supposed to be copying.
388 Go for it.
389 */
390 pr_debug("Folding chain %d into unit %d\n", thisVUC, targetEUN);
391 for (block = 0; block < nftl->EraseSize / 512 ; block++) {
392 unsigned char movebuf[512];
393 int ret;
394
395 /* If it's in the target EUN already, or if it's pending write, do nothing */
396 if (BlockMap[block] == targetEUN ||
397 (pendingblock == (thisVUC * (nftl->EraseSize / 512) + block))) {
398 continue;
399 }
400
401 /* copy only in non free block (free blocks can only
402 happen in case of media errors or deleted blocks) */
403 if (BlockMap[block] == BLOCK_NIL)
404 continue;
405
406 ret = mtd_read(mtd,
407 (nftl->EraseSize * BlockMap[block]) + (block * 512),
408 512,
409 &retlen,
410 movebuf);
411 if (ret < 0 && !mtd_is_bitflip(ret)) {
412 ret = mtd_read(mtd,
413 (nftl->EraseSize * BlockMap[block]) + (block * 512),
414 512,
415 &retlen,
416 movebuf);
417 if (ret != -EIO)
418 printk("Error went away on retry.\n");
419 }
420 memset(&oob, 0xff, sizeof(struct nftl_oob));
421 oob.b.Status = oob.b.Status1 = SECTOR_USED;
422
423 nftl_write(nftl->mbd.mtd, (nftl->EraseSize * targetEUN) +
424 (block * 512), 512, &retlen, movebuf, (char *)&oob);
425 }
426
427 /* add the header so that it is now a valid chain */
428 oob.u.a.VirtUnitNum = oob.u.a.SpareVirtUnitNum = cpu_to_le16(thisVUC);
429 oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum = BLOCK_NIL;
430
431 nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 8,
432 8, &retlen, (char *)&oob.u);
433
434 /* OK. We've moved the whole lot into the new block. Now we have to free the original blocks. */
435
436 /* At this point, we have two different chains for this Virtual Unit, and no way to tell
437 them apart. If we crash now, we get confused. However, both contain the same data, so we
438 shouldn't actually lose data in this case. It's just that when we load up on a medium which
439 has duplicate chains, we need to free one of the chains because it's not necessary any more.
440 */
441 thisEUN = nftl->EUNtable[thisVUC];
442 pr_debug("Want to erase\n");
443
444 /* For each block in the old chain (except the targetEUN of course),
445 free it and make it available for future use */
446 while (thisEUN <= nftl->lastEUN && thisEUN != targetEUN) {
447 unsigned int EUNtmp;
448
449 EUNtmp = nftl->ReplUnitTable[thisEUN];
450
451 if (NFTL_formatblock(nftl, thisEUN) < 0) {
452 /* could not erase : mark block as reserved
453 */
454 nftl->ReplUnitTable[thisEUN] = BLOCK_RESERVED;
455 } else {
456 /* correctly erased : mark it as free */
457 nftl->ReplUnitTable[thisEUN] = BLOCK_FREE;
458 nftl->numfreeEUNs++;
459 }
460 thisEUN = EUNtmp;
461 }
462
463 /* Make this the new start of chain for thisVUC */
464 nftl->ReplUnitTable[targetEUN] = BLOCK_NIL;
465 nftl->EUNtable[thisVUC] = targetEUN;
466
467 return targetEUN;
468}
469
470static u16 NFTL_makefreeblock( struct NFTLrecord *nftl , unsigned pendingblock)
471{
472 /* This is the part that needs some cleverness applied.
473 For now, I'm doing the minimum applicable to actually
474 get the thing to work.
475 Wear-levelling and other clever stuff needs to be implemented
476 and we also need to do some assessment of the results when
477 the system loses power half-way through the routine.
478 */
479 u16 LongestChain = 0;
480 u16 ChainLength = 0, thislen;
481 u16 chain, EUN;
482
483 for (chain = 0; chain < le32_to_cpu(nftl->MediaHdr.FormattedSize) / nftl->EraseSize; chain++) {
484 EUN = nftl->EUNtable[chain];
485 thislen = 0;
486
487 while (EUN <= nftl->lastEUN) {
488 thislen++;
489 //printk("VUC %d reaches len %d with EUN %d\n", chain, thislen, EUN);
490 EUN = nftl->ReplUnitTable[EUN] & 0x7fff;
491 if (thislen > 0xff00) {
492 printk("Endless loop in Virtual Chain %d: Unit %x\n",
493 chain, EUN);
494 }
495 if (thislen > 0xff10) {
496 /* Actually, don't return failure. Just ignore this chain and
497 get on with it. */
498 thislen = 0;
499 break;
500 }
501 }
502
503 if (thislen > ChainLength) {
504 //printk("New longest chain is %d with length %d\n", chain, thislen);
505 ChainLength = thislen;
506 LongestChain = chain;
507 }
508 }
509
510 if (ChainLength < 2) {
511 printk(KERN_WARNING "No Virtual Unit Chains available for folding. "
512 "Failing request\n");
513 return BLOCK_NIL;
514 }
515
516 return NFTL_foldchain (nftl, LongestChain, pendingblock);
517}
518
519/* NFTL_findwriteunit: Return the unit number into which we can write
520 for this block. Make it available if it isn't already
521*/
522static inline u16 NFTL_findwriteunit(struct NFTLrecord *nftl, unsigned block)
523{
524 u16 lastEUN;
525 u16 thisVUC = block / (nftl->EraseSize / 512);
526 struct mtd_info *mtd = nftl->mbd.mtd;
527 unsigned int writeEUN;
528 unsigned long blockofs = (block * 512) & (nftl->EraseSize -1);
529 size_t retlen;
530 int silly, silly2 = 3;
531 struct nftl_oob oob;
532
533 do {
534 /* Scan the media to find a unit in the VUC which has
535 a free space for the block in question.
536 */
537
538 /* This condition catches the 0x[7f]fff cases, as well as
539 being a sanity check for past-end-of-media access
540 */
541 lastEUN = BLOCK_NIL;
542 writeEUN = nftl->EUNtable[thisVUC];
543 silly = MAX_LOOPS;
544 while (writeEUN <= nftl->lastEUN) {
545 struct nftl_bci bci;
546 size_t retlen;
547 unsigned int status;
548
549 lastEUN = writeEUN;
550
551 nftl_read_oob(mtd,
552 (writeEUN * nftl->EraseSize) + blockofs,
553 8, &retlen, (char *)&bci);
554
555 pr_debug("Status of block %d in EUN %d is %x\n",
556 block , writeEUN, le16_to_cpu(bci.Status));
557
558 status = bci.Status | bci.Status1;
559 switch(status) {
560 case SECTOR_FREE:
561 return writeEUN;
562
563 case SECTOR_DELETED:
564 case SECTOR_USED:
565 case SECTOR_IGNORE:
566 break;
567 default:
568 // Invalid block. Don't use it any more. Must implement.
569 break;
570 }
571
572 if (!silly--) {
573 printk(KERN_WARNING
574 "Infinite loop in Virtual Unit Chain 0x%x\n",
575 thisVUC);
576 return BLOCK_NIL;
577 }
578
579 /* Skip to next block in chain */
580 writeEUN = nftl->ReplUnitTable[writeEUN];
581 }
582
583 /* OK. We didn't find one in the existing chain, or there
584 is no existing chain. */
585
586 /* Try to find an already-free block */
587 writeEUN = NFTL_findfreeblock(nftl, 0);
588
589 if (writeEUN == BLOCK_NIL) {
590 /* That didn't work - there were no free blocks just
591 waiting to be picked up. We're going to have to fold
592 a chain to make room.
593 */
594
595 /* First remember the start of this chain */
596 //u16 startEUN = nftl->EUNtable[thisVUC];
597
598 //printk("Write to VirtualUnitChain %d, calling makefreeblock()\n", thisVUC);
599 writeEUN = NFTL_makefreeblock(nftl, BLOCK_NIL);
600
601 if (writeEUN == BLOCK_NIL) {
602 /* OK, we accept that the above comment is
603 lying - there may have been free blocks
604 last time we called NFTL_findfreeblock(),
605 but they are reserved for when we're
606 desperate. Well, now we're desperate.
607 */
608 pr_debug("Using desperate==1 to find free EUN to accommodate write to VUC %d\n", thisVUC);
609 writeEUN = NFTL_findfreeblock(nftl, 1);
610 }
611 if (writeEUN == BLOCK_NIL) {
612 /* Ouch. This should never happen - we should
613 always be able to make some room somehow.
614 If we get here, we've allocated more storage
615 space than actual media, or our makefreeblock
616 routine is missing something.
617 */
618 printk(KERN_WARNING "Cannot make free space.\n");
619 return BLOCK_NIL;
620 }
621 //printk("Restarting scan\n");
622 continue;
623 }
624
625 /* We've found a free block. Insert it into the chain. */
626
627 if (lastEUN != BLOCK_NIL) {
628 thisVUC |= 0x8000; /* It's a replacement block */
629 } else {
630 /* The first block in a new chain */
631 nftl->EUNtable[thisVUC] = writeEUN;
632 }
633
634 /* set up the actual EUN we're writing into */
635 /* Both in our cache... */
636 nftl->ReplUnitTable[writeEUN] = BLOCK_NIL;
637
638 /* ... and on the flash itself */
639 nftl_read_oob(mtd, writeEUN * nftl->EraseSize + 8, 8,
640 &retlen, (char *)&oob.u);
641
642 oob.u.a.VirtUnitNum = oob.u.a.SpareVirtUnitNum = cpu_to_le16(thisVUC);
643
644 nftl_write_oob(mtd, writeEUN * nftl->EraseSize + 8, 8,
645 &retlen, (char *)&oob.u);
646
647 /* we link the new block to the chain only after the
648 block is ready. It avoids the case where the chain
649 could point to a free block */
650 if (lastEUN != BLOCK_NIL) {
651 /* Both in our cache... */
652 nftl->ReplUnitTable[lastEUN] = writeEUN;
653 /* ... and on the flash itself */
654 nftl_read_oob(mtd, (lastEUN * nftl->EraseSize) + 8,
655 8, &retlen, (char *)&oob.u);
656
657 oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum
658 = cpu_to_le16(writeEUN);
659
660 nftl_write_oob(mtd, (lastEUN * nftl->EraseSize) + 8,
661 8, &retlen, (char *)&oob.u);
662 }
663
664 return writeEUN;
665
666 } while (silly2--);
667
668 printk(KERN_WARNING "Error folding to make room for Virtual Unit Chain 0x%x\n",
669 thisVUC);
670 return BLOCK_NIL;
671}
672
673static int nftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
674 char *buffer)
675{
676 struct NFTLrecord *nftl = (void *)mbd;
677 u16 writeEUN;
678 unsigned long blockofs = (block * 512) & (nftl->EraseSize - 1);
679 size_t retlen;
680 struct nftl_oob oob;
681
682 writeEUN = NFTL_findwriteunit(nftl, block);
683
684 if (writeEUN == BLOCK_NIL) {
685 printk(KERN_WARNING
686 "NFTL_writeblock(): Cannot find block to write to\n");
687 /* If we _still_ haven't got a block to use, we're screwed */
688 return 1;
689 }
690
691 memset(&oob, 0xff, sizeof(struct nftl_oob));
692 oob.b.Status = oob.b.Status1 = SECTOR_USED;
693
694 nftl_write(nftl->mbd.mtd, (writeEUN * nftl->EraseSize) + blockofs,
695 512, &retlen, (char *)buffer, (char *)&oob);
696 return 0;
697}
698#endif /* CONFIG_NFTL_RW */
699
700static int nftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
701 char *buffer)
702{
703 struct NFTLrecord *nftl = (void *)mbd;
704 struct mtd_info *mtd = nftl->mbd.mtd;
705 u16 lastgoodEUN;
706 u16 thisEUN = nftl->EUNtable[block / (nftl->EraseSize / 512)];
707 unsigned long blockofs = (block * 512) & (nftl->EraseSize - 1);
708 unsigned int status;
709 int silly = MAX_LOOPS;
710 size_t retlen;
711 struct nftl_bci bci;
712
713 lastgoodEUN = BLOCK_NIL;
714
715 if (thisEUN != BLOCK_NIL) {
716 while (thisEUN < nftl->nb_blocks) {
717 if (nftl_read_oob(mtd, (thisEUN * nftl->EraseSize) +
718 blockofs, 8, &retlen,
719 (char *)&bci) < 0)
720 status = SECTOR_IGNORE;
721 else
722 status = bci.Status | bci.Status1;
723
724 switch (status) {
725 case SECTOR_FREE:
726 /* no modification of a sector should follow a free sector */
727 goto the_end;
728 case SECTOR_DELETED:
729 lastgoodEUN = BLOCK_NIL;
730 break;
731 case SECTOR_USED:
732 lastgoodEUN = thisEUN;
733 break;
734 case SECTOR_IGNORE:
735 break;
736 default:
737 printk("Unknown status for block %ld in EUN %d: %x\n",
738 block, thisEUN, status);
739 break;
740 }
741
742 if (!silly--) {
743 printk(KERN_WARNING "Infinite loop in Virtual Unit Chain 0x%lx\n",
744 block / (nftl->EraseSize / 512));
745 return 1;
746 }
747 thisEUN = nftl->ReplUnitTable[thisEUN];
748 }
749 }
750
751 the_end:
752 if (lastgoodEUN == BLOCK_NIL) {
753 /* the requested block is not on the media, return all 0x00 */
754 memset(buffer, 0, 512);
755 } else {
756 loff_t ptr = (lastgoodEUN * nftl->EraseSize) + blockofs;
757 size_t retlen;
758 int res = mtd_read(mtd, ptr, 512, &retlen, buffer);
759
760 if (res < 0 && !mtd_is_bitflip(res))
761 return -EIO;
762 }
763 return 0;
764}
765
766static int nftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
767{
768 struct NFTLrecord *nftl = (void *)dev;
769
770 geo->heads = nftl->heads;
771 geo->sectors = nftl->sectors;
772 geo->cylinders = nftl->cylinders;
773
774 return 0;
775}
776
777/****************************************************************************
778 *
779 * Module stuff
780 *
781 ****************************************************************************/
782
783
784static struct mtd_blktrans_ops nftl_tr = {
785 .name = "nftl",
786 .major = NFTL_MAJOR,
787 .part_bits = NFTL_PARTN_BITS,
788 .blksize = 512,
789 .getgeo = nftl_getgeo,
790 .readsect = nftl_readblock,
791#ifdef CONFIG_NFTL_RW
792 .writesect = nftl_writeblock,
793#endif
794 .add_mtd = nftl_add_mtd,
795 .remove_dev = nftl_remove_dev,
796 .owner = THIS_MODULE,
797};
798
799module_mtd_blktrans(nftl_tr);
800
801MODULE_LICENSE("GPL");
802MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
803MODULE_DESCRIPTION("Support code for NAND Flash Translation Layer, used on M-Systems DiskOnChip 2000 and Millennium");
804MODULE_ALIAS_BLOCKDEV_MAJOR(NFTL_MAJOR);
1/*
2 * Linux driver for NAND Flash Translation Layer
3 *
4 * Copyright © 1999 Machine Vision Holdings, Inc.
5 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#define PRERELEASE
23
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <asm/errno.h>
27#include <asm/io.h>
28#include <asm/uaccess.h>
29#include <linux/delay.h>
30#include <linux/slab.h>
31#include <linux/init.h>
32#include <linux/hdreg.h>
33#include <linux/blkdev.h>
34
35#include <linux/kmod.h>
36#include <linux/mtd/mtd.h>
37#include <linux/mtd/nand.h>
38#include <linux/mtd/nftl.h>
39#include <linux/mtd/blktrans.h>
40
41/* maximum number of loops while examining next block, to have a
42 chance to detect consistency problems (they should never happen
43 because of the checks done in the mounting */
44
45#define MAX_LOOPS 10000
46
47
48static void nftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
49{
50 struct NFTLrecord *nftl;
51 unsigned long temp;
52
53 if (mtd->type != MTD_NANDFLASH || mtd->size > UINT_MAX)
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"NFTL 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_LEVEL1, "NFTL: add_mtd for %s\n", mtd->name);
67
68 nftl = kzalloc(sizeof(struct NFTLrecord), GFP_KERNEL);
69
70 if (!nftl) {
71 printk(KERN_WARNING "NFTL: out of memory for data structures\n");
72 return;
73 }
74
75 nftl->mbd.mtd = mtd;
76 nftl->mbd.devnum = -1;
77
78 nftl->mbd.tr = tr;
79
80 if (NFTL_mount(nftl) < 0) {
81 printk(KERN_WARNING "NFTL: could not mount device\n");
82 kfree(nftl);
83 return;
84 }
85
86 /* OK, it's a new one. Set up all the data structures. */
87
88 /* Calculate geometry */
89 nftl->cylinders = 1024;
90 nftl->heads = 16;
91
92 temp = nftl->cylinders * nftl->heads;
93 nftl->sectors = nftl->mbd.size / temp;
94 if (nftl->mbd.size % temp) {
95 nftl->sectors++;
96 temp = nftl->cylinders * nftl->sectors;
97 nftl->heads = nftl->mbd.size / temp;
98
99 if (nftl->mbd.size % temp) {
100 nftl->heads++;
101 temp = nftl->heads * nftl->sectors;
102 nftl->cylinders = nftl->mbd.size / temp;
103 }
104 }
105
106 if (nftl->mbd.size != nftl->heads * nftl->cylinders * nftl->sectors) {
107 /*
108 Oh no we don't have
109 mbd.size == heads * cylinders * sectors
110 */
111 printk(KERN_WARNING "NFTL: cannot calculate a geometry to "
112 "match size of 0x%lx.\n", nftl->mbd.size);
113 printk(KERN_WARNING "NFTL: using C:%d H:%d S:%d "
114 "(== 0x%lx sects)\n",
115 nftl->cylinders, nftl->heads , nftl->sectors,
116 (long)nftl->cylinders * (long)nftl->heads *
117 (long)nftl->sectors );
118 }
119
120 if (add_mtd_blktrans_dev(&nftl->mbd)) {
121 kfree(nftl->ReplUnitTable);
122 kfree(nftl->EUNtable);
123 kfree(nftl);
124 return;
125 }
126#ifdef PSYCHO_DEBUG
127 printk(KERN_INFO "NFTL: Found new nftl%c\n", nftl->mbd.devnum + 'a');
128#endif
129}
130
131static void nftl_remove_dev(struct mtd_blktrans_dev *dev)
132{
133 struct NFTLrecord *nftl = (void *)dev;
134
135 DEBUG(MTD_DEBUG_LEVEL1, "NFTL: remove_dev (i=%d)\n", dev->devnum);
136
137 del_mtd_blktrans_dev(dev);
138 kfree(nftl->ReplUnitTable);
139 kfree(nftl->EUNtable);
140}
141
142/*
143 * Read oob data from flash
144 */
145int nftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
146 size_t *retlen, uint8_t *buf)
147{
148 loff_t mask = mtd->writesize - 1;
149 struct mtd_oob_ops ops;
150 int res;
151
152 ops.mode = MTD_OOB_PLACE;
153 ops.ooboffs = offs & mask;
154 ops.ooblen = len;
155 ops.oobbuf = buf;
156 ops.datbuf = NULL;
157
158 res = mtd->read_oob(mtd, offs & ~mask, &ops);
159 *retlen = ops.oobretlen;
160 return res;
161}
162
163/*
164 * Write oob data to flash
165 */
166int nftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
167 size_t *retlen, uint8_t *buf)
168{
169 loff_t mask = mtd->writesize - 1;
170 struct mtd_oob_ops ops;
171 int res;
172
173 ops.mode = MTD_OOB_PLACE;
174 ops.ooboffs = offs & mask;
175 ops.ooblen = len;
176 ops.oobbuf = buf;
177 ops.datbuf = NULL;
178
179 res = mtd->write_oob(mtd, offs & ~mask, &ops);
180 *retlen = ops.oobretlen;
181 return res;
182}
183
184#ifdef CONFIG_NFTL_RW
185
186/*
187 * Write data and oob to flash
188 */
189static int nftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
190 size_t *retlen, uint8_t *buf, uint8_t *oob)
191{
192 loff_t mask = mtd->writesize - 1;
193 struct mtd_oob_ops ops;
194 int res;
195
196 ops.mode = MTD_OOB_PLACE;
197 ops.ooboffs = offs & mask;
198 ops.ooblen = mtd->oobsize;
199 ops.oobbuf = oob;
200 ops.datbuf = buf;
201 ops.len = len;
202
203 res = mtd->write_oob(mtd, offs & ~mask, &ops);
204 *retlen = ops.retlen;
205 return res;
206}
207
208/* Actual NFTL access routines */
209/* NFTL_findfreeblock: Find a free Erase Unit on the NFTL partition. This function is used
210 * when the give Virtual Unit Chain
211 */
212static u16 NFTL_findfreeblock(struct NFTLrecord *nftl, int desperate )
213{
214 /* For a given Virtual Unit Chain: find or create a free block and
215 add it to the chain */
216 /* We're passed the number of the last EUN in the chain, to save us from
217 having to look it up again */
218 u16 pot = nftl->LastFreeEUN;
219 int silly = nftl->nb_blocks;
220
221 /* Normally, we force a fold to happen before we run out of free blocks completely */
222 if (!desperate && nftl->numfreeEUNs < 2) {
223 DEBUG(MTD_DEBUG_LEVEL1, "NFTL_findfreeblock: there are too few free EUNs\n");
224 return BLOCK_NIL;
225 }
226
227 /* Scan for a free block */
228 do {
229 if (nftl->ReplUnitTable[pot] == BLOCK_FREE) {
230 nftl->LastFreeEUN = pot;
231 nftl->numfreeEUNs--;
232 return pot;
233 }
234
235 /* This will probably point to the MediaHdr unit itself,
236 right at the beginning of the partition. But that unit
237 (and the backup unit too) should have the UCI set
238 up so that it's not selected for overwriting */
239 if (++pot > nftl->lastEUN)
240 pot = le16_to_cpu(nftl->MediaHdr.FirstPhysicalEUN);
241
242 if (!silly--) {
243 printk("Argh! No free blocks found! LastFreeEUN = %d, "
244 "FirstEUN = %d\n", nftl->LastFreeEUN,
245 le16_to_cpu(nftl->MediaHdr.FirstPhysicalEUN));
246 return BLOCK_NIL;
247 }
248 } while (pot != nftl->LastFreeEUN);
249
250 return BLOCK_NIL;
251}
252
253static u16 NFTL_foldchain (struct NFTLrecord *nftl, unsigned thisVUC, unsigned pendingblock )
254{
255 struct mtd_info *mtd = nftl->mbd.mtd;
256 u16 BlockMap[MAX_SECTORS_PER_UNIT];
257 unsigned char BlockLastState[MAX_SECTORS_PER_UNIT];
258 unsigned char BlockFreeFound[MAX_SECTORS_PER_UNIT];
259 unsigned int thisEUN;
260 int block;
261 int silly;
262 unsigned int targetEUN;
263 struct nftl_oob oob;
264 int inplace = 1;
265 size_t retlen;
266
267 memset(BlockMap, 0xff, sizeof(BlockMap));
268 memset(BlockFreeFound, 0, sizeof(BlockFreeFound));
269
270 thisEUN = nftl->EUNtable[thisVUC];
271
272 if (thisEUN == BLOCK_NIL) {
273 printk(KERN_WARNING "Trying to fold non-existent "
274 "Virtual Unit Chain %d!\n", thisVUC);
275 return BLOCK_NIL;
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 targetEUN = BLOCK_NIL;
283 while (thisEUN <= nftl->lastEUN ) {
284 unsigned int status, foldmark;
285
286 targetEUN = thisEUN;
287 for (block = 0; block < nftl->EraseSize / 512; block ++) {
288 nftl_read_oob(mtd, (thisEUN * nftl->EraseSize) +
289 (block * 512), 16 , &retlen,
290 (char *)&oob);
291 if (block == 2) {
292 foldmark = oob.u.c.FoldMark | oob.u.c.FoldMark1;
293 if (foldmark == FOLD_MARK_IN_PROGRESS) {
294 DEBUG(MTD_DEBUG_LEVEL1,
295 "Write Inhibited on EUN %d\n", thisEUN);
296 inplace = 0;
297 } else {
298 /* There's no other reason not to do inplace,
299 except ones that come later. So we don't need
300 to preserve inplace */
301 inplace = 1;
302 }
303 }
304 status = oob.b.Status | oob.b.Status1;
305 BlockLastState[block] = status;
306
307 switch(status) {
308 case SECTOR_FREE:
309 BlockFreeFound[block] = 1;
310 break;
311
312 case SECTOR_USED:
313 if (!BlockFreeFound[block])
314 BlockMap[block] = thisEUN;
315 else
316 printk(KERN_WARNING
317 "SECTOR_USED found after SECTOR_FREE "
318 "in Virtual Unit Chain %d for block %d\n",
319 thisVUC, block);
320 break;
321 case SECTOR_DELETED:
322 if (!BlockFreeFound[block])
323 BlockMap[block] = BLOCK_NIL;
324 else
325 printk(KERN_WARNING
326 "SECTOR_DELETED found after SECTOR_FREE "
327 "in Virtual Unit Chain %d for block %d\n",
328 thisVUC, block);
329 break;
330
331 case SECTOR_IGNORE:
332 break;
333 default:
334 printk("Unknown status for block %d in EUN %d: %x\n",
335 block, thisEUN, status);
336 }
337 }
338
339 if (!silly--) {
340 printk(KERN_WARNING "Infinite loop in Virtual Unit Chain 0x%x\n",
341 thisVUC);
342 return BLOCK_NIL;
343 }
344
345 thisEUN = nftl->ReplUnitTable[thisEUN];
346 }
347
348 if (inplace) {
349 /* We're being asked to be a fold-in-place. Check
350 that all blocks which actually have data associated
351 with them (i.e. BlockMap[block] != BLOCK_NIL) are
352 either already present or SECTOR_FREE in the target
353 block. If not, we're going to have to fold out-of-place
354 anyway.
355 */
356 for (block = 0; block < nftl->EraseSize / 512 ; block++) {
357 if (BlockLastState[block] != SECTOR_FREE &&
358 BlockMap[block] != BLOCK_NIL &&
359 BlockMap[block] != targetEUN) {
360 DEBUG(MTD_DEBUG_LEVEL1, "Setting inplace to 0. VUC %d, "
361 "block %d was %x lastEUN, "
362 "and is in EUN %d (%s) %d\n",
363 thisVUC, block, BlockLastState[block],
364 BlockMap[block],
365 BlockMap[block]== targetEUN ? "==" : "!=",
366 targetEUN);
367 inplace = 0;
368 break;
369 }
370 }
371
372 if (pendingblock >= (thisVUC * (nftl->EraseSize / 512)) &&
373 pendingblock < ((thisVUC + 1)* (nftl->EraseSize / 512)) &&
374 BlockLastState[pendingblock - (thisVUC * (nftl->EraseSize / 512))] !=
375 SECTOR_FREE) {
376 DEBUG(MTD_DEBUG_LEVEL1, "Pending write not free in EUN %d. "
377 "Folding out of place.\n", targetEUN);
378 inplace = 0;
379 }
380 }
381
382 if (!inplace) {
383 DEBUG(MTD_DEBUG_LEVEL1, "Cannot fold Virtual Unit Chain %d in place. "
384 "Trying out-of-place\n", thisVUC);
385 /* We need to find a targetEUN to fold into. */
386 targetEUN = NFTL_findfreeblock(nftl, 1);
387 if (targetEUN == BLOCK_NIL) {
388 /* Ouch. Now we're screwed. We need to do a
389 fold-in-place of another chain to make room
390 for this one. We need a better way of selecting
391 which chain to fold, because makefreeblock will
392 only ask us to fold the same one again.
393 */
394 printk(KERN_WARNING
395 "NFTL_findfreeblock(desperate) returns 0xffff.\n");
396 return BLOCK_NIL;
397 }
398 } else {
399 /* We put a fold mark in the chain we are folding only if we
400 fold in place to help the mount check code. If we do not fold in
401 place, it is possible to find the valid chain by selecting the
402 longer one */
403 oob.u.c.FoldMark = oob.u.c.FoldMark1 = cpu_to_le16(FOLD_MARK_IN_PROGRESS);
404 oob.u.c.unused = 0xffffffff;
405 nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 2 * 512 + 8,
406 8, &retlen, (char *)&oob.u);
407 }
408
409 /* OK. We now know the location of every block in the Virtual Unit Chain,
410 and the Erase Unit into which we are supposed to be copying.
411 Go for it.
412 */
413 DEBUG(MTD_DEBUG_LEVEL1,"Folding chain %d into unit %d\n", thisVUC, targetEUN);
414 for (block = 0; block < nftl->EraseSize / 512 ; block++) {
415 unsigned char movebuf[512];
416 int ret;
417
418 /* If it's in the target EUN already, or if it's pending write, do nothing */
419 if (BlockMap[block] == targetEUN ||
420 (pendingblock == (thisVUC * (nftl->EraseSize / 512) + block))) {
421 continue;
422 }
423
424 /* copy only in non free block (free blocks can only
425 happen in case of media errors or deleted blocks) */
426 if (BlockMap[block] == BLOCK_NIL)
427 continue;
428
429 ret = mtd->read(mtd, (nftl->EraseSize * BlockMap[block]) + (block * 512),
430 512, &retlen, movebuf);
431 if (ret < 0 && ret != -EUCLEAN) {
432 ret = mtd->read(mtd, (nftl->EraseSize * BlockMap[block])
433 + (block * 512), 512, &retlen,
434 movebuf);
435 if (ret != -EIO)
436 printk("Error went away on retry.\n");
437 }
438 memset(&oob, 0xff, sizeof(struct nftl_oob));
439 oob.b.Status = oob.b.Status1 = SECTOR_USED;
440
441 nftl_write(nftl->mbd.mtd, (nftl->EraseSize * targetEUN) +
442 (block * 512), 512, &retlen, movebuf, (char *)&oob);
443 }
444
445 /* add the header so that it is now a valid chain */
446 oob.u.a.VirtUnitNum = oob.u.a.SpareVirtUnitNum = cpu_to_le16(thisVUC);
447 oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum = BLOCK_NIL;
448
449 nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 8,
450 8, &retlen, (char *)&oob.u);
451
452 /* OK. We've moved the whole lot into the new block. Now we have to free the original blocks. */
453
454 /* At this point, we have two different chains for this Virtual Unit, and no way to tell
455 them apart. If we crash now, we get confused. However, both contain the same data, so we
456 shouldn't actually lose data in this case. It's just that when we load up on a medium which
457 has duplicate chains, we need to free one of the chains because it's not necessary any more.
458 */
459 thisEUN = nftl->EUNtable[thisVUC];
460 DEBUG(MTD_DEBUG_LEVEL1,"Want to erase\n");
461
462 /* For each block in the old chain (except the targetEUN of course),
463 free it and make it available for future use */
464 while (thisEUN <= nftl->lastEUN && thisEUN != targetEUN) {
465 unsigned int EUNtmp;
466
467 EUNtmp = nftl->ReplUnitTable[thisEUN];
468
469 if (NFTL_formatblock(nftl, thisEUN) < 0) {
470 /* could not erase : mark block as reserved
471 */
472 nftl->ReplUnitTable[thisEUN] = BLOCK_RESERVED;
473 } else {
474 /* correctly erased : mark it as free */
475 nftl->ReplUnitTable[thisEUN] = BLOCK_FREE;
476 nftl->numfreeEUNs++;
477 }
478 thisEUN = EUNtmp;
479 }
480
481 /* Make this the new start of chain for thisVUC */
482 nftl->ReplUnitTable[targetEUN] = BLOCK_NIL;
483 nftl->EUNtable[thisVUC] = targetEUN;
484
485 return targetEUN;
486}
487
488static u16 NFTL_makefreeblock( struct NFTLrecord *nftl , unsigned pendingblock)
489{
490 /* This is the part that needs some cleverness applied.
491 For now, I'm doing the minimum applicable to actually
492 get the thing to work.
493 Wear-levelling and other clever stuff needs to be implemented
494 and we also need to do some assessment of the results when
495 the system loses power half-way through the routine.
496 */
497 u16 LongestChain = 0;
498 u16 ChainLength = 0, thislen;
499 u16 chain, EUN;
500
501 for (chain = 0; chain < le32_to_cpu(nftl->MediaHdr.FormattedSize) / nftl->EraseSize; chain++) {
502 EUN = nftl->EUNtable[chain];
503 thislen = 0;
504
505 while (EUN <= nftl->lastEUN) {
506 thislen++;
507 //printk("VUC %d reaches len %d with EUN %d\n", chain, thislen, EUN);
508 EUN = nftl->ReplUnitTable[EUN] & 0x7fff;
509 if (thislen > 0xff00) {
510 printk("Endless loop in Virtual Chain %d: Unit %x\n",
511 chain, EUN);
512 }
513 if (thislen > 0xff10) {
514 /* Actually, don't return failure. Just ignore this chain and
515 get on with it. */
516 thislen = 0;
517 break;
518 }
519 }
520
521 if (thislen > ChainLength) {
522 //printk("New longest chain is %d with length %d\n", chain, thislen);
523 ChainLength = thislen;
524 LongestChain = chain;
525 }
526 }
527
528 if (ChainLength < 2) {
529 printk(KERN_WARNING "No Virtual Unit Chains available for folding. "
530 "Failing request\n");
531 return BLOCK_NIL;
532 }
533
534 return NFTL_foldchain (nftl, LongestChain, pendingblock);
535}
536
537/* NFTL_findwriteunit: Return the unit number into which we can write
538 for this block. Make it available if it isn't already
539*/
540static inline u16 NFTL_findwriteunit(struct NFTLrecord *nftl, unsigned block)
541{
542 u16 lastEUN;
543 u16 thisVUC = block / (nftl->EraseSize / 512);
544 struct mtd_info *mtd = nftl->mbd.mtd;
545 unsigned int writeEUN;
546 unsigned long blockofs = (block * 512) & (nftl->EraseSize -1);
547 size_t retlen;
548 int silly, silly2 = 3;
549 struct nftl_oob oob;
550
551 do {
552 /* Scan the media to find a unit in the VUC which has
553 a free space for the block in question.
554 */
555
556 /* This condition catches the 0x[7f]fff cases, as well as
557 being a sanity check for past-end-of-media access
558 */
559 lastEUN = BLOCK_NIL;
560 writeEUN = nftl->EUNtable[thisVUC];
561 silly = MAX_LOOPS;
562 while (writeEUN <= nftl->lastEUN) {
563 struct nftl_bci bci;
564 size_t retlen;
565 unsigned int status;
566
567 lastEUN = writeEUN;
568
569 nftl_read_oob(mtd,
570 (writeEUN * nftl->EraseSize) + blockofs,
571 8, &retlen, (char *)&bci);
572
573 DEBUG(MTD_DEBUG_LEVEL2, "Status of block %d in EUN %d is %x\n",
574 block , writeEUN, le16_to_cpu(bci.Status));
575
576 status = bci.Status | bci.Status1;
577 switch(status) {
578 case SECTOR_FREE:
579 return writeEUN;
580
581 case SECTOR_DELETED:
582 case SECTOR_USED:
583 case SECTOR_IGNORE:
584 break;
585 default:
586 // Invalid block. Don't use it any more. Must implement.
587 break;
588 }
589
590 if (!silly--) {
591 printk(KERN_WARNING
592 "Infinite loop in Virtual Unit Chain 0x%x\n",
593 thisVUC);
594 return BLOCK_NIL;
595 }
596
597 /* Skip to next block in chain */
598 writeEUN = nftl->ReplUnitTable[writeEUN];
599 }
600
601 /* OK. We didn't find one in the existing chain, or there
602 is no existing chain. */
603
604 /* Try to find an already-free block */
605 writeEUN = NFTL_findfreeblock(nftl, 0);
606
607 if (writeEUN == BLOCK_NIL) {
608 /* That didn't work - there were no free blocks just
609 waiting to be picked up. We're going to have to fold
610 a chain to make room.
611 */
612
613 /* First remember the start of this chain */
614 //u16 startEUN = nftl->EUNtable[thisVUC];
615
616 //printk("Write to VirtualUnitChain %d, calling makefreeblock()\n", thisVUC);
617 writeEUN = NFTL_makefreeblock(nftl, BLOCK_NIL);
618
619 if (writeEUN == BLOCK_NIL) {
620 /* OK, we accept that the above comment is
621 lying - there may have been free blocks
622 last time we called NFTL_findfreeblock(),
623 but they are reserved for when we're
624 desperate. Well, now we're desperate.
625 */
626 DEBUG(MTD_DEBUG_LEVEL1, "Using desperate==1 to find free EUN to accommodate write to VUC %d\n", thisVUC);
627 writeEUN = NFTL_findfreeblock(nftl, 1);
628 }
629 if (writeEUN == BLOCK_NIL) {
630 /* Ouch. This should never happen - we should
631 always be able to make some room somehow.
632 If we get here, we've allocated more storage
633 space than actual media, or our makefreeblock
634 routine is missing something.
635 */
636 printk(KERN_WARNING "Cannot make free space.\n");
637 return BLOCK_NIL;
638 }
639 //printk("Restarting scan\n");
640 lastEUN = BLOCK_NIL;
641 continue;
642 }
643
644 /* We've found a free block. Insert it into the chain. */
645
646 if (lastEUN != BLOCK_NIL) {
647 thisVUC |= 0x8000; /* It's a replacement block */
648 } else {
649 /* The first block in a new chain */
650 nftl->EUNtable[thisVUC] = writeEUN;
651 }
652
653 /* set up the actual EUN we're writing into */
654 /* Both in our cache... */
655 nftl->ReplUnitTable[writeEUN] = BLOCK_NIL;
656
657 /* ... and on the flash itself */
658 nftl_read_oob(mtd, writeEUN * nftl->EraseSize + 8, 8,
659 &retlen, (char *)&oob.u);
660
661 oob.u.a.VirtUnitNum = oob.u.a.SpareVirtUnitNum = cpu_to_le16(thisVUC);
662
663 nftl_write_oob(mtd, writeEUN * nftl->EraseSize + 8, 8,
664 &retlen, (char *)&oob.u);
665
666 /* we link the new block to the chain only after the
667 block is ready. It avoids the case where the chain
668 could point to a free block */
669 if (lastEUN != BLOCK_NIL) {
670 /* Both in our cache... */
671 nftl->ReplUnitTable[lastEUN] = writeEUN;
672 /* ... and on the flash itself */
673 nftl_read_oob(mtd, (lastEUN * nftl->EraseSize) + 8,
674 8, &retlen, (char *)&oob.u);
675
676 oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum
677 = cpu_to_le16(writeEUN);
678
679 nftl_write_oob(mtd, (lastEUN * nftl->EraseSize) + 8,
680 8, &retlen, (char *)&oob.u);
681 }
682
683 return writeEUN;
684
685 } while (silly2--);
686
687 printk(KERN_WARNING "Error folding to make room for Virtual Unit Chain 0x%x\n",
688 thisVUC);
689 return BLOCK_NIL;
690}
691
692static int nftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
693 char *buffer)
694{
695 struct NFTLrecord *nftl = (void *)mbd;
696 u16 writeEUN;
697 unsigned long blockofs = (block * 512) & (nftl->EraseSize - 1);
698 size_t retlen;
699 struct nftl_oob oob;
700
701 writeEUN = NFTL_findwriteunit(nftl, block);
702
703 if (writeEUN == BLOCK_NIL) {
704 printk(KERN_WARNING
705 "NFTL_writeblock(): Cannot find block to write to\n");
706 /* If we _still_ haven't got a block to use, we're screwed */
707 return 1;
708 }
709
710 memset(&oob, 0xff, sizeof(struct nftl_oob));
711 oob.b.Status = oob.b.Status1 = SECTOR_USED;
712
713 nftl_write(nftl->mbd.mtd, (writeEUN * nftl->EraseSize) + blockofs,
714 512, &retlen, (char *)buffer, (char *)&oob);
715 return 0;
716}
717#endif /* CONFIG_NFTL_RW */
718
719static int nftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
720 char *buffer)
721{
722 struct NFTLrecord *nftl = (void *)mbd;
723 struct mtd_info *mtd = nftl->mbd.mtd;
724 u16 lastgoodEUN;
725 u16 thisEUN = nftl->EUNtable[block / (nftl->EraseSize / 512)];
726 unsigned long blockofs = (block * 512) & (nftl->EraseSize - 1);
727 unsigned int status;
728 int silly = MAX_LOOPS;
729 size_t retlen;
730 struct nftl_bci bci;
731
732 lastgoodEUN = BLOCK_NIL;
733
734 if (thisEUN != BLOCK_NIL) {
735 while (thisEUN < nftl->nb_blocks) {
736 if (nftl_read_oob(mtd, (thisEUN * nftl->EraseSize) +
737 blockofs, 8, &retlen,
738 (char *)&bci) < 0)
739 status = SECTOR_IGNORE;
740 else
741 status = bci.Status | bci.Status1;
742
743 switch (status) {
744 case SECTOR_FREE:
745 /* no modification of a sector should follow a free sector */
746 goto the_end;
747 case SECTOR_DELETED:
748 lastgoodEUN = BLOCK_NIL;
749 break;
750 case SECTOR_USED:
751 lastgoodEUN = thisEUN;
752 break;
753 case SECTOR_IGNORE:
754 break;
755 default:
756 printk("Unknown status for block %ld in EUN %d: %x\n",
757 block, thisEUN, status);
758 break;
759 }
760
761 if (!silly--) {
762 printk(KERN_WARNING "Infinite loop in Virtual Unit Chain 0x%lx\n",
763 block / (nftl->EraseSize / 512));
764 return 1;
765 }
766 thisEUN = nftl->ReplUnitTable[thisEUN];
767 }
768 }
769
770 the_end:
771 if (lastgoodEUN == BLOCK_NIL) {
772 /* the requested block is not on the media, return all 0x00 */
773 memset(buffer, 0, 512);
774 } else {
775 loff_t ptr = (lastgoodEUN * nftl->EraseSize) + blockofs;
776 size_t retlen;
777 int res = mtd->read(mtd, ptr, 512, &retlen, buffer);
778
779 if (res < 0 && res != -EUCLEAN)
780 return -EIO;
781 }
782 return 0;
783}
784
785static int nftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
786{
787 struct NFTLrecord *nftl = (void *)dev;
788
789 geo->heads = nftl->heads;
790 geo->sectors = nftl->sectors;
791 geo->cylinders = nftl->cylinders;
792
793 return 0;
794}
795
796/****************************************************************************
797 *
798 * Module stuff
799 *
800 ****************************************************************************/
801
802
803static struct mtd_blktrans_ops nftl_tr = {
804 .name = "nftl",
805 .major = NFTL_MAJOR,
806 .part_bits = NFTL_PARTN_BITS,
807 .blksize = 512,
808 .getgeo = nftl_getgeo,
809 .readsect = nftl_readblock,
810#ifdef CONFIG_NFTL_RW
811 .writesect = nftl_writeblock,
812#endif
813 .add_mtd = nftl_add_mtd,
814 .remove_dev = nftl_remove_dev,
815 .owner = THIS_MODULE,
816};
817
818static int __init init_nftl(void)
819{
820 return register_mtd_blktrans(&nftl_tr);
821}
822
823static void __exit cleanup_nftl(void)
824{
825 deregister_mtd_blktrans(&nftl_tr);
826}
827
828module_init(init_nftl);
829module_exit(cleanup_nftl);
830
831MODULE_LICENSE("GPL");
832MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
833MODULE_DESCRIPTION("Support code for NAND Flash Translation Layer, used on M-Systems DiskOnChip 2000 and Millennium");
834MODULE_ALIAS_BLOCKDEV_MAJOR(NFTL_MAJOR);