yaffs_packedtags2.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_packedtags2.h"
  15 #include "yportenv.h"
  16 #include "yaffs_tagsvalidity.h"
  17
  18 /* This code packs a set of extended tags into a binary structure for
  19  * NAND storage
  20  */
  21
  22 /* Some of the information is "extra" struff which can be packed in to
  23  * speed scanning
  24  * This is defined by having the EXTRA_HEADER_INFO_FLAG set.
  25  */
  26
  27 /* Extra flags applied to chunkId */
  28
  29 #define EXTRA_HEADER_INFO_FLAG  0x80000000
  30 #define EXTRA_SHRINK_FLAG       0x40000000
  31 #define EXTRA_SHADOWS_FLAG      0x20000000
  32 #define EXTRA_SPARE_FLAGS       0x10000000
  33
  34 #define ALL_EXTRA_FLAGS         0xF0000000
  35
  36 /* Also, the top 4 bits of the object Id are set to the object type. */
  37 #define EXTRA_OBJECT_TYPE_SHIFT (28)
  38 #define EXTRA_OBJECT_TYPE_MASK  ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT)
  39
  40
  41 static void yaffs_DumpPackedTags2TagsPart(const yaffs_PackedTags2TagsPart *ptt)
  42 {
  43         T(YAFFS_TRACE_MTD,
  44           (TSTR("packed tags obj %d chunk %d byte %d seq %d" TENDSTR),
  45            ptt->objectId, ptt->chunkId, ptt->byteCount,
  46            ptt->sequenceNumber));
  47 }
  48 static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 *pt)
  49 {
  50         yaffs_DumpPackedTags2TagsPart(&pt->t);
  51 }
  52
  53 static void yaffs_DumpTags2(const yaffs_ExtendedTags *t)
  54 {
  55         T(YAFFS_TRACE_MTD,
  56           (TSTR
  57            ("ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte %d del %d ser %d seq %d"
  58             TENDSTR), t->eccResult, t->blockBad, t->chunkUsed, t->objectId,
  59            t->chunkId, t->byteCount, t->chunkDeleted, t->serialNumber,
  60            t->sequenceNumber));
  61
  62 }
  63
  64 void yaffs_PackTags2TagsPart(yaffs_PackedTags2TagsPart *ptt,
  65                 const yaffs_ExtendedTags *t)
  66 {
  67         ptt->chunkId = t->chunkId;
  68         ptt->sequenceNumber = t->sequenceNumber;
  69         ptt->byteCount = t->byteCount;
  70         ptt->objectId = t->objectId;
  71
  72         if (t->chunkId == 0 && t->extraHeaderInfoAvailable) {
  73                 /* Store the extra header info instead */
  74                 /* We save the parent object in the chunkId */
  75                 ptt->chunkId = EXTRA_HEADER_INFO_FLAG
  76                         | t->extraParentObjectId;
  77                 if (t->extraIsShrinkHeader) {
  78                         ptt->chunkId |= EXTRA_SHRINK_FLAG;
  79                 }
  80                 if (t->extraShadows) {
  81                         ptt->chunkId |= EXTRA_SHADOWS_FLAG;
  82                 }
  83
  84                 ptt->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
  85                 ptt->objectId |=
  86                     (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
  87
  88                 if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) {
  89                         ptt->byteCount = t->extraEquivalentObjectId;
  90                 } else if (t->extraObjectType == YAFFS_OBJECT_TYPE_FILE) {
  91                         ptt->byteCount = t->extraFileLength;
  92                 } else {
  93                         ptt->byteCount = 0;
  94                 }
  95         }
  96
  97         yaffs_DumpPackedTags2TagsPart(ptt);
  98         yaffs_DumpTags2(t);
  99 }
 100
 101
 102 void yaffs_PackTags2(yaffs_PackedTags2 *pt, const yaffs_ExtendedTags *t)
 103 {
 104         yaffs_PackTags2TagsPart(&pt->t, t);
 105
 106 #ifndef YAFFS_IGNORE_TAGS_ECC
 107         {
 108                 yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 109                                         sizeof(yaffs_PackedTags2TagsPart),
 110                                         &pt->ecc);
 111         }
 112 #endif
 113 }
 114
 115
 116 void yaffs_UnpackTags2TagsPart(yaffs_ExtendedTags *t,
 117                 yaffs_PackedTags2TagsPart *ptt)
 118 {
 119
 120         memset(t, 0, sizeof(yaffs_ExtendedTags));
 121
 122         yaffs_InitialiseTags(t);
 123
 124         if (ptt->sequenceNumber != 0xFFFFFFFF) {
 125                 t->blockBad = 0;
 126                 t->chunkUsed = 1;
 127                 t->objectId = ptt->objectId;
 128                 t->chunkId = ptt->chunkId;
 129                 t->byteCount = ptt->byteCount;
 130                 t->chunkDeleted = 0;
 131                 t->serialNumber = 0;
 132                 t->sequenceNumber = ptt->sequenceNumber;
 133
 134                 /* Do extra header info stuff */
 135
 136                 if (ptt->chunkId & EXTRA_HEADER_INFO_FLAG) {
 137                         t->chunkId = 0;
 138                         t->byteCount = 0;
 139
 140                         t->extraHeaderInfoAvailable = 1;
 141                         t->extraParentObjectId =
 142                             ptt->chunkId & (~(ALL_EXTRA_FLAGS));
 143                         t->extraIsShrinkHeader =
 144                             (ptt->chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
 145                         t->extraShadows =
 146                             (ptt->chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
 147                         t->extraObjectType =
 148                             ptt->objectId >> EXTRA_OBJECT_TYPE_SHIFT;
 149                         t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
 150
 151                         if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) {
 152                                 t->extraEquivalentObjectId = ptt->byteCount;
 153                         } else {
 154                                 t->extraFileLength = ptt->byteCount;
 155                         }
 156                 }
 157         }
 158
 159         yaffs_DumpPackedTags2TagsPart(ptt);
 160         yaffs_DumpTags2(t);
 161
 162 }
 163
 164
 165 void yaffs_UnpackTags2(yaffs_ExtendedTags *t, yaffs_PackedTags2 *pt)
 166 {
 167
 168         yaffs_ECCResult eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 169
 170         if (pt->t.sequenceNumber != 0xFFFFFFFF) {
 171                 /* Page is in use */
 172 #ifndef YAFFS_IGNORE_TAGS_ECC
 173                 {
 174                         yaffs_ECCOther ecc;
 175                         int result;
 176                         yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 177                                                 sizeof
 178                                                 (yaffs_PackedTags2TagsPart),
 179                                                 &ecc);
 180                         result =
 181                             yaffs_ECCCorrectOther((unsigned char *)&pt->t,
 182                                                   sizeof
 183                                                   (yaffs_PackedTags2TagsPart),
 184                                                   &pt->ecc, &ecc);
 185                         switch (result) {
 186                         case 0:
 187                                 eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 188                                 break;
 189                         case 1:
 190                                 eccResult = YAFFS_ECC_RESULT_FIXED;
 191                                 break;
 192                         case -1:
 193                                 eccResult = YAFFS_ECC_RESULT_UNFIXED;
 194                                 break;
 195                         default:
 196                                 eccResult = YAFFS_ECC_RESULT_UNKNOWN;
 197                         }
 198                 }
 199 #endif
 200         }
 201
 202         yaffs_UnpackTags2TagsPart(t, &pt->t);
 203
 204         t->eccResult = eccResult;
 205
 206         yaffs_DumpPackedTags2(pt);
 207         yaffs_DumpTags2(t);
 208
 209 }
 210