Root/target/linux/generic-2.6/files/fs/yaffs2/yaffs_tagscompat.c

1/*
2 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
3 *
4 * Copyright (C) 2002-2007 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
6 *
7 * Created by Charles Manning <charles@aleph1.co.uk>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include "yaffs_guts.h"
15#include "yaffs_tagscompat.h"
16#include "yaffs_ecc.h"
17
18static void yaffs_HandleReadDataError(yaffs_Device * dev, int chunkInNAND);
19#ifdef NOTYET
20static void yaffs_CheckWrittenBlock(yaffs_Device * dev, int chunkInNAND);
21static void yaffs_HandleWriteChunkOk(yaffs_Device * dev, int chunkInNAND,
22                     const __u8 * data,
23                     const yaffs_Spare * spare);
24static void yaffs_HandleUpdateChunk(yaffs_Device * dev, int chunkInNAND,
25                    const yaffs_Spare * spare);
26static void yaffs_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND);
27#endif
28
29static const char yaffs_countBitsTable[256] = {
30    0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
31    1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
32    1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
33    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
34    1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
35    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
36    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
37    3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
38    1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
39    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
40    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
41    3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
42    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
43    3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
44    3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
45    4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
46};
47
48int yaffs_CountBits(__u8 x)
49{
50    int retVal;
51    retVal = yaffs_countBitsTable[x];
52    return retVal;
53}
54
55/********** Tags ECC calculations *********/
56
57void yaffs_CalcECC(const __u8 * data, yaffs_Spare * spare)
58{
59    yaffs_ECCCalculate(data, spare->ecc1);
60    yaffs_ECCCalculate(&data[256], spare->ecc2);
61}
62
63void yaffs_CalcTagsECC(yaffs_Tags * tags)
64{
65    /* Calculate an ecc */
66
67    unsigned char *b = ((yaffs_TagsUnion *) tags)->asBytes;
68    unsigned i, j;
69    unsigned ecc = 0;
70    unsigned bit = 0;
71
72    tags->ecc = 0;
73
74    for (i = 0; i < 8; i++) {
75        for (j = 1; j & 0xff; j <<= 1) {
76            bit++;
77            if (b[i] & j) {
78                ecc ^= bit;
79            }
80        }
81    }
82
83    tags->ecc = ecc;
84
85}
86
87int yaffs_CheckECCOnTags(yaffs_Tags * tags)
88{
89    unsigned ecc = tags->ecc;
90
91    yaffs_CalcTagsECC(tags);
92
93    ecc ^= tags->ecc;
94
95    if (ecc && ecc <= 64) {
96        /* TODO: Handle the failure better. Retire? */
97        unsigned char *b = ((yaffs_TagsUnion *) tags)->asBytes;
98
99        ecc--;
100
101        b[ecc / 8] ^= (1 << (ecc & 7));
102
103        /* Now recvalc the ecc */
104        yaffs_CalcTagsECC(tags);
105
106        return 1; /* recovered error */
107    } else if (ecc) {
108        /* Wierd ecc failure value */
109        /* TODO Need to do somethiong here */
110        return -1; /* unrecovered error */
111    }
112
113    return 0;
114}
115
116/********** Tags **********/
117
118static void yaffs_LoadTagsIntoSpare(yaffs_Spare * sparePtr,
119                    yaffs_Tags * tagsPtr)
120{
121    yaffs_TagsUnion *tu = (yaffs_TagsUnion *) tagsPtr;
122
123    yaffs_CalcTagsECC(tagsPtr);
124
125    sparePtr->tagByte0 = tu->asBytes[0];
126    sparePtr->tagByte1 = tu->asBytes[1];
127    sparePtr->tagByte2 = tu->asBytes[2];
128    sparePtr->tagByte3 = tu->asBytes[3];
129    sparePtr->tagByte4 = tu->asBytes[4];
130    sparePtr->tagByte5 = tu->asBytes[5];
131    sparePtr->tagByte6 = tu->asBytes[6];
132    sparePtr->tagByte7 = tu->asBytes[7];
133}
134
135static void yaffs_GetTagsFromSpare(yaffs_Device * dev, yaffs_Spare * sparePtr,
136                   yaffs_Tags * tagsPtr)
137{
138    yaffs_TagsUnion *tu = (yaffs_TagsUnion *) tagsPtr;
139    int result;
140
141    tu->asBytes[0] = sparePtr->tagByte0;
142    tu->asBytes[1] = sparePtr->tagByte1;
143    tu->asBytes[2] = sparePtr->tagByte2;
144    tu->asBytes[3] = sparePtr->tagByte3;
145    tu->asBytes[4] = sparePtr->tagByte4;
146    tu->asBytes[5] = sparePtr->tagByte5;
147    tu->asBytes[6] = sparePtr->tagByte6;
148    tu->asBytes[7] = sparePtr->tagByte7;
149
150    result = yaffs_CheckECCOnTags(tagsPtr);
151    if (result > 0) {
152        dev->tagsEccFixed++;
153    } else if (result < 0) {
154        dev->tagsEccUnfixed++;
155    }
156}
157
158static void yaffs_SpareInitialise(yaffs_Spare * spare)
159{
160    memset(spare, 0xFF, sizeof(yaffs_Spare));
161}
162
163static int yaffs_WriteChunkToNAND(struct yaffs_DeviceStruct *dev,
164                  int chunkInNAND, const __u8 * data,
165                  yaffs_Spare * spare)
166{
167    if (chunkInNAND < dev->startBlock * dev->nChunksPerBlock) {
168        T(YAFFS_TRACE_ERROR,
169          (TSTR("**>> yaffs chunk %d is not valid" TENDSTR),
170           chunkInNAND));
171        return YAFFS_FAIL;
172    }
173
174    dev->nPageWrites++;
175    return dev->writeChunkToNAND(dev, chunkInNAND, data, spare);
176}
177
178static int yaffs_ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,
179                   int chunkInNAND,
180                   __u8 * data,
181                   yaffs_Spare * spare,
182                   yaffs_ECCResult * eccResult,
183                   int doErrorCorrection)
184{
185    int retVal;
186    yaffs_Spare localSpare;
187
188    dev->nPageReads++;
189
190    if (!spare && data) {
191        /* If we don't have a real spare, then we use a local one. */
192        /* Need this for the calculation of the ecc */
193        spare = &localSpare;
194    }
195
196    if (!dev->useNANDECC) {
197        retVal = dev->readChunkFromNAND(dev, chunkInNAND, data, spare);
198        if (data && doErrorCorrection) {
199            /* Do ECC correction */
200            /* Todo handle any errors */
201            int eccResult1, eccResult2;
202            __u8 calcEcc[3];
203
204            yaffs_ECCCalculate(data, calcEcc);
205            eccResult1 =
206                yaffs_ECCCorrect(data, spare->ecc1, calcEcc);
207            yaffs_ECCCalculate(&data[256], calcEcc);
208            eccResult2 =
209                yaffs_ECCCorrect(&data[256], spare->ecc2, calcEcc);
210
211            if (eccResult1 > 0) {
212                T(YAFFS_TRACE_ERROR,
213                  (TSTR
214                   ("**>>yaffs ecc error fix performed on chunk %d:0"
215                    TENDSTR), chunkInNAND));
216                dev->eccFixed++;
217            } else if (eccResult1 < 0) {
218                T(YAFFS_TRACE_ERROR,
219                  (TSTR
220                   ("**>>yaffs ecc error unfixed on chunk %d:0"
221                    TENDSTR), chunkInNAND));
222                dev->eccUnfixed++;
223            }
224
225            if (eccResult2 > 0) {
226                T(YAFFS_TRACE_ERROR,
227                  (TSTR
228                   ("**>>yaffs ecc error fix performed on chunk %d:1"
229                    TENDSTR), chunkInNAND));
230                dev->eccFixed++;
231            } else if (eccResult2 < 0) {
232                T(YAFFS_TRACE_ERROR,
233                  (TSTR
234                   ("**>>yaffs ecc error unfixed on chunk %d:1"
235                    TENDSTR), chunkInNAND));
236                dev->eccUnfixed++;
237            }
238
239            if (eccResult1 || eccResult2) {
240                /* We had a data problem on this page */
241                yaffs_HandleReadDataError(dev, chunkInNAND);
242            }
243
244            if (eccResult1 < 0 || eccResult2 < 0)
245                *eccResult = YAFFS_ECC_RESULT_UNFIXED;
246            else if (eccResult1 > 0 || eccResult2 > 0)
247                *eccResult = YAFFS_ECC_RESULT_FIXED;
248            else
249                *eccResult = YAFFS_ECC_RESULT_NO_ERROR;
250        }
251    } else {
252        /* Must allocate enough memory for spare+2*sizeof(int) */
253        /* for ecc results from device. */
254        struct yaffs_NANDSpare nspare;
255        retVal =
256            dev->readChunkFromNAND(dev, chunkInNAND, data,
257                       (yaffs_Spare *) & nspare);
258        memcpy(spare, &nspare, sizeof(yaffs_Spare));
259        if (data && doErrorCorrection) {
260            if (nspare.eccres1 > 0) {
261                T(YAFFS_TRACE_ERROR,
262                  (TSTR
263                   ("**>>mtd ecc error fix performed on chunk %d:0"
264                    TENDSTR), chunkInNAND));
265            } else if (nspare.eccres1 < 0) {
266                T(YAFFS_TRACE_ERROR,
267                  (TSTR
268                   ("**>>mtd ecc error unfixed on chunk %d:0"
269                    TENDSTR), chunkInNAND));
270            }
271
272            if (nspare.eccres2 > 0) {
273                T(YAFFS_TRACE_ERROR,
274                  (TSTR
275                   ("**>>mtd ecc error fix performed on chunk %d:1"
276                    TENDSTR), chunkInNAND));
277            } else if (nspare.eccres2 < 0) {
278                T(YAFFS_TRACE_ERROR,
279                  (TSTR
280                   ("**>>mtd ecc error unfixed on chunk %d:1"
281                    TENDSTR), chunkInNAND));
282            }
283
284            if (nspare.eccres1 || nspare.eccres2) {
285                /* We had a data problem on this page */
286                yaffs_HandleReadDataError(dev, chunkInNAND);
287            }
288
289            if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
290                *eccResult = YAFFS_ECC_RESULT_UNFIXED;
291            else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
292                *eccResult = YAFFS_ECC_RESULT_FIXED;
293            else
294                *eccResult = YAFFS_ECC_RESULT_NO_ERROR;
295
296        }
297    }
298    return retVal;
299}
300
301#ifdef NOTYET
302static int yaffs_CheckChunkErased(struct yaffs_DeviceStruct *dev,
303                  int chunkInNAND)
304{
305
306    static int init = 0;
307    static __u8 cmpbuf[YAFFS_BYTES_PER_CHUNK];
308    static __u8 data[YAFFS_BYTES_PER_CHUNK];
309    /* Might as well always allocate the larger size for */
310    /* dev->useNANDECC == true; */
311    static __u8 spare[sizeof(struct yaffs_NANDSpare)];
312
313    dev->readChunkFromNAND(dev, chunkInNAND, data, (yaffs_Spare *) spare);
314
315    if (!init) {
316        memset(cmpbuf, 0xff, YAFFS_BYTES_PER_CHUNK);
317        init = 1;
318    }
319
320    if (memcmp(cmpbuf, data, YAFFS_BYTES_PER_CHUNK))
321        return YAFFS_FAIL;
322    if (memcmp(cmpbuf, spare, 16))
323        return YAFFS_FAIL;
324
325    return YAFFS_OK;
326
327}
328#endif
329
330/*
331 * Functions for robustisizing
332 */
333
334static void yaffs_HandleReadDataError(yaffs_Device * dev, int chunkInNAND)
335{
336    int blockInNAND = chunkInNAND / dev->nChunksPerBlock;
337
338    /* Mark the block for retirement */
339    yaffs_GetBlockInfo(dev, blockInNAND)->needsRetiring = 1;
340    T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
341      (TSTR("**>>Block %d marked for retirement" TENDSTR), blockInNAND));
342
343    /* TODO:
344     * Just do a garbage collection on the affected block
345     * then retire the block
346     * NB recursion
347     */
348}
349
350#ifdef NOTYET
351static void yaffs_CheckWrittenBlock(yaffs_Device * dev, int chunkInNAND)
352{
353}
354
355static void yaffs_HandleWriteChunkOk(yaffs_Device * dev, int chunkInNAND,
356                     const __u8 * data,
357                     const yaffs_Spare * spare)
358{
359}
360
361static void yaffs_HandleUpdateChunk(yaffs_Device * dev, int chunkInNAND,
362                    const yaffs_Spare * spare)
363{
364}
365
366static void yaffs_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND)
367{
368    int blockInNAND = chunkInNAND / dev->nChunksPerBlock;
369
370    /* Mark the block for retirement */
371    yaffs_GetBlockInfo(dev, blockInNAND)->needsRetiring = 1;
372    /* Delete the chunk */
373    yaffs_DeleteChunk(dev, chunkInNAND, 1, __LINE__);
374}
375
376static int yaffs_VerifyCompare(const __u8 * d0, const __u8 * d1,
377                   const yaffs_Spare * s0, const yaffs_Spare * s1)
378{
379
380    if (memcmp(d0, d1, YAFFS_BYTES_PER_CHUNK) != 0 ||
381        s0->tagByte0 != s1->tagByte0 ||
382        s0->tagByte1 != s1->tagByte1 ||
383        s0->tagByte2 != s1->tagByte2 ||
384        s0->tagByte3 != s1->tagByte3 ||
385        s0->tagByte4 != s1->tagByte4 ||
386        s0->tagByte5 != s1->tagByte5 ||
387        s0->tagByte6 != s1->tagByte6 ||
388        s0->tagByte7 != s1->tagByte7 ||
389        s0->ecc1[0] != s1->ecc1[0] ||
390        s0->ecc1[1] != s1->ecc1[1] ||
391        s0->ecc1[2] != s1->ecc1[2] ||
392        s0->ecc2[0] != s1->ecc2[0] ||
393        s0->ecc2[1] != s1->ecc2[1] || s0->ecc2[2] != s1->ecc2[2]) {
394        return 0;
395    }
396
397    return 1;
398}
399#endif /* NOTYET */
400
401int yaffs_TagsCompatabilityWriteChunkWithTagsToNAND(yaffs_Device * dev,
402                            int chunkInNAND,
403                            const __u8 * data,
404                            const yaffs_ExtendedTags *
405                            eTags)
406{
407    yaffs_Spare spare;
408    yaffs_Tags tags;
409
410    yaffs_SpareInitialise(&spare);
411
412    if (eTags->chunkDeleted) {
413        spare.pageStatus = 0;
414    } else {
415        tags.objectId = eTags->objectId;
416        tags.chunkId = eTags->chunkId;
417        tags.byteCount = eTags->byteCount;
418        tags.serialNumber = eTags->serialNumber;
419
420        if (!dev->useNANDECC && data) {
421            yaffs_CalcECC(data, &spare);
422        }
423        yaffs_LoadTagsIntoSpare(&spare, &tags);
424
425    }
426
427    return yaffs_WriteChunkToNAND(dev, chunkInNAND, data, &spare);
428}
429
430int yaffs_TagsCompatabilityReadChunkWithTagsFromNAND(yaffs_Device * dev,
431                             int chunkInNAND,
432                             __u8 * data,
433                             yaffs_ExtendedTags * eTags)
434{
435
436    yaffs_Spare spare;
437    yaffs_Tags tags;
438    yaffs_ECCResult eccResult;
439
440    static yaffs_Spare spareFF;
441    static int init;
442
443    if (!init) {
444        memset(&spareFF, 0xFF, sizeof(spareFF));
445        init = 1;
446    }
447
448    if (yaffs_ReadChunkFromNAND
449        (dev, chunkInNAND, data, &spare, &eccResult, 1)) {
450        /* eTags may be NULL */
451        if (eTags) {
452
453            int deleted =
454                (yaffs_CountBits(spare.pageStatus) < 7) ? 1 : 0;
455
456            eTags->chunkDeleted = deleted;
457            eTags->eccResult = eccResult;
458            eTags->blockBad = 0; /* We're reading it */
459            /* therefore it is not a bad block */
460            eTags->chunkUsed =
461                (memcmp(&spareFF, &spare, sizeof(spareFF)) !=
462                 0) ? 1 : 0;
463
464            if (eTags->chunkUsed) {
465                yaffs_GetTagsFromSpare(dev, &spare, &tags);
466
467                eTags->objectId = tags.objectId;
468                eTags->chunkId = tags.chunkId;
469                eTags->byteCount = tags.byteCount;
470                eTags->serialNumber = tags.serialNumber;
471            }
472        }
473
474        return YAFFS_OK;
475    } else {
476        return YAFFS_FAIL;
477    }
478}
479
480int yaffs_TagsCompatabilityMarkNANDBlockBad(struct yaffs_DeviceStruct *dev,
481                        int blockInNAND)
482{
483
484    yaffs_Spare spare;
485
486    memset(&spare, 0xff, sizeof(yaffs_Spare));
487
488    spare.blockStatus = 'Y';
489
490    yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock, NULL,
491                   &spare);
492    yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock + 1,
493                   NULL, &spare);
494
495    return YAFFS_OK;
496
497}
498
499int yaffs_TagsCompatabilityQueryNANDBlock(struct yaffs_DeviceStruct *dev,
500                      int blockNo, yaffs_BlockState *
501                      state,
502                      int *sequenceNumber)
503{
504
505    yaffs_Spare spare0, spare1;
506    static yaffs_Spare spareFF;
507    static int init;
508    yaffs_ECCResult dummy;
509
510    if (!init) {
511        memset(&spareFF, 0xFF, sizeof(spareFF));
512        init = 1;
513    }
514
515    *sequenceNumber = 0;
516
517    yaffs_ReadChunkFromNAND(dev, blockNo * dev->nChunksPerBlock, NULL,
518                &spare0, &dummy, 1);
519    yaffs_ReadChunkFromNAND(dev, blockNo * dev->nChunksPerBlock + 1, NULL,
520                &spare1, &dummy, 1);
521
522    if (yaffs_CountBits(spare0.blockStatus & spare1.blockStatus) < 7)
523        *state = YAFFS_BLOCK_STATE_DEAD;
524    else if (memcmp(&spareFF, &spare0, sizeof(spareFF)) == 0)
525        *state = YAFFS_BLOCK_STATE_EMPTY;
526    else
527        *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
528
529    return YAFFS_OK;
530}
531

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