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