target/linux/generic/files/fs/yaffs2/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                 if (t->extraShadows)
  80                         ptt->chunkId |= EXTRA_SHADOWS_FLAG;
  81
  82                 ptt->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
  83                 ptt->objectId |=
  84                     (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
  85
  86                 if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
  87                         ptt->byteCount = t->extraEquivalentObjectId;
  88                 else if (t->extraObjectType == YAFFS_OBJECT_TYPE_FILE)
  89                         ptt->byteCount = t->extraFileLength;
  90                 else
  91                         ptt->byteCount = 0;
  92         }
  93
  94         yaffs_DumpPackedTags2TagsPart(ptt);
  95         yaffs_DumpTags2(t);
  96 }
  97
  98
  99 void yaffs_PackTags2(yaffs_PackedTags2 *pt, const yaffs_ExtendedTags *t)
 100 {
 101         yaffs_PackTags2TagsPart(&pt->t, t);
 102
 103 #ifndef YAFFS_IGNORE_TAGS_ECC
 104         {
 105                 yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 106                                         sizeof(yaffs_PackedTags2TagsPart),
 107                                         &pt->ecc);
 108         }
 109 #endif
 110 }
 111
 112
 113 void yaffs_UnpackTags2TagsPart(yaffs_ExtendedTags *t,
 114                 yaffs_PackedTags2TagsPart *ptt)
 115 {
 116
 117         memset(t, 0, sizeof(yaffs_ExtendedTags));
 118
 119         yaffs_InitialiseTags(t);
 120
 121         if (ptt->sequenceNumber != 0xFFFFFFFF) {
 122                 t->blockBad = 0;
 123                 t->chunkUsed = 1;
 124                 t->objectId = ptt->objectId;
 125                 t->chunkId = ptt->chunkId;
 126                 t->byteCount = ptt->byteCount;
 127                 t->chunkDeleted = 0;
 128                 t->serialNumber = 0;
 129                 t->sequenceNumber = ptt->sequenceNumber;
 130
 131                 /* Do extra header info stuff */
 132
 133                 if (ptt->chunkId & EXTRA_HEADER_INFO_FLAG) {
 134                         t->chunkId = 0;
 135                         t->byteCount = 0;
 136
 137                         t->extraHeaderInfoAvailable = 1;
 138                         t->extraParentObjectId =
 139                             ptt->chunkId & (~(ALL_EXTRA_FLAGS));
 140                         t->extraIsShrinkHeader =
 141                             (ptt->chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
 142                         t->extraShadows =
 143                             (ptt->chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
 144                         t->extraObjectType =
 145                             ptt->objectId >> EXTRA_OBJECT_TYPE_SHIFT;
 146                         t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
 147
 148                         if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
 149                                 t->extraEquivalentObjectId = ptt->byteCount;
 150                         else
 151                                 t->extraFileLength = ptt->byteCount;
 152                 }
 153         }
 154
 155         yaffs_DumpPackedTags2TagsPart(ptt);
 156         yaffs_DumpTags2(t);
 157
 158 }
 159
 160
 161 void yaffs_UnpackTags2(yaffs_ExtendedTags *t, yaffs_PackedTags2 *pt)
 162 {
 163
 164         yaffs_ECCResult eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 165
 166         if (pt->t.sequenceNumber != 0xFFFFFFFF) {
 167                 /* Page is in use */
 168 #ifndef YAFFS_IGNORE_TAGS_ECC
 169                 {
 170                         yaffs_ECCOther ecc;
 171                         int result;
 172                         yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 173                                                 sizeof
 174                                                 (yaffs_PackedTags2TagsPart),
 175                                                 &ecc);
 176                         result =
 177                             yaffs_ECCCorrectOther((unsigned char *)&pt->t,
 178                                                   sizeof
 179                                                   (yaffs_PackedTags2TagsPart),
 180                                                   &pt->ecc, &ecc);
 181                         switch (result) {
 182                         case 0:
 183                                 eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 184                                 break;
 185                         case 1:
 186                                 eccResult = YAFFS_ECC_RESULT_FIXED;
 187                                 break;
 188                         case -1:
 189                                 eccResult = YAFFS_ECC_RESULT_UNFIXED;
 190                                 break;
 191                         default:
 192                                 eccResult = YAFFS_ECC_RESULT_UNKNOWN;
 193                         }
 194                 }
 195 #endif
 196         }
 197
 198         yaffs_UnpackTags2TagsPart(t, &pt->t);
 199
 200         t->eccResult = eccResult;
 201
 202         yaffs_DumpPackedTags2(pt);
 203         yaffs_DumpTags2(t);
 204
 205 }
 206