yaffs_ramem2k.c

   1 /*
   2  * YAFFS: Yet another FFS. A NAND-flash specific file system.
   3  * yaffs_ramem.c  NAND emulation on top of a chunk of RAM
   4  *
   5  * Copyright (C) 2002 Aleph One Ltd.
   6  *   for Toby Churchill Ltd and Brightstar Engineering
   7  *
   8  * Created by Charles Manning <charles@aleph1.co.uk>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  */
  15  //yaffs_ramem2k.c: RAM emulation in-kernel for 2K pages (YAFFS2)
  16
  17
  18 const char *yaffs_ramem2k_c_version = "$Id: yaffs_ramem2k.c,v 1.2 2005-04-24 09:26:08 charles Exp $";
  19
  20 #ifndef __KERNEL__
  21 #define CONFIG_YAFFS_RAM_ENABLED
  22 #endif
  23
  24 #ifdef CONFIG_YAFFS_RAM_ENABLED
  25
  26 #include "yportenv.h"
  27
  28 #include "yaffs_nandemul2k.h"
  29 #include "yaffs_guts.h"
  30 #include "yaffsinterface.h"
  31 #include "devextras.h"
  32 #include "yaffs_packedtags2.h"
  33
  34
  35
  36 #define EM_SIZE_IN_MEG (32)
  37 #define PAGE_DATA_SIZE  (2048)
  38 #define PAGE_SPARE_SIZE (64)
  39 #define PAGES_PER_BLOCK (64)
  40
  41
  42
  43 #define EM_SIZE_IN_BYTES (EM_SIZE_IN_MEG * (1<<20))
  44
  45 #define PAGE_TOTAL_SIZE (PAGE_DATA_SIZE+PAGE_SPARE_SIZE)
  46
  47 #define BLOCK_TOTAL_SIZE (PAGES_PER_BLOCK * PAGE_TOTAL_SIZE)
  48
  49 #define BLOCKS_PER_MEG ((1<<20)/(PAGES_PER_BLOCK * PAGE_DATA_SIZE))
  50
  51
  52 typedef struct
  53 {
  54         __u8 data[PAGE_TOTAL_SIZE]; // Data + spare
  55         int empty;      // is this empty?
  56 } nandemul_Page;
  57
  58
  59 typedef struct
  60 {
  61         nandemul_Page *page[PAGES_PER_BLOCK];
  62         int damaged;
  63 } nandemul_Block;
  64
  65
  66
  67 typedef struct
  68 {
  69         nandemul_Block**block;
  70         int nBlocks;
  71 } nandemul_Device;
  72
  73 static nandemul_Device ned;
  74
  75 static int sizeInMB = EM_SIZE_IN_MEG;
  76
  77
  78 static void nandemul_yield(int n)
  79 {
  80 #ifdef __KERNEL__
  81         if(n > 0) schedule_timeout(n);
  82 #endif
  83
  84 }
  85
  86
  87 static void nandemul_ReallyEraseBlock(int blockNumber)
  88 {
  89         int i;
  90
  91         nandemul_Block *blk;
  92
  93         if(blockNumber < 0 || blockNumber >= ned.nBlocks)
  94         {
  95                 return;
  96         }
  97
  98         blk = ned.block[blockNumber];
  99
 100         for(i = 0; i < PAGES_PER_BLOCK; i++)
 101         {
 102                 memset(blk->page[i],0xff,sizeof(nandemul_Page));
 103                 blk->page[i]->empty = 1;
 104         }
 105         nandemul_yield(2);
 106 }
 107
 108
 109 static int nandemul2k_CalcNBlocks(void)
 110 {
 111         return EM_SIZE_IN_MEG * BLOCKS_PER_MEG;
 112 }
 113
 114
 115
 116 static int  CheckInit(void)
 117 {
 118         static int initialised = 0;
 119
 120         int i,j;
 121
 122         int fail = 0;
 123         int nBlocks;
 124
 125         int nAllocated = 0;
 126
 127         if(initialised)
 128         {
 129                 return YAFFS_OK;
 130         }
 131
 132
 133         ned.nBlocks = nBlocks = nandemul2k_CalcNBlocks();
 134
 135
 136         ned.block = YMALLOC(sizeof(nandemul_Block*) * nBlocks );
 137
 138         if(!ned.block) return YAFFS_FAIL;
 139
 140
 141
 142
 143
 144         for(i=fail=0; i <nBlocks; i++)
 145         {
 146
 147                 nandemul_Block *blk;
 148
 149                 if(!(blk = ned.block[i] = YMALLOC(sizeof(nandemul_Block))))
 150                 {
 151                  fail = 1;
 152                 }
 153                 else
 154                 {
 155                         for(j = 0; j < PAGES_PER_BLOCK; j++)
 156                         {
 157                                 if((blk->page[j] = YMALLOC(sizeof(nandemul_Page))) == 0)
 158                                 {
 159                                         fail = 1;
 160                                 }
 161                         }
 162                         nandemul_ReallyEraseBlock(i);
 163                         ned.block[i]->damaged = 0;
 164                         nAllocated++;
 165                 }
 166         }
 167
 168         if(fail)
 169         {
 170                 //Todo thump pages
 171
 172                 for(i = 0; i < nAllocated; i++)
 173                 {
 174                         YFREE(ned.block[i]);
 175                 }
 176                 YFREE(ned.block);
 177
 178                 T(YAFFS_TRACE_ALWAYS,("Allocation failed, could only allocate %dMB of %dMB requested.\n",
 179                    nAllocated/64,sizeInMB));
 180                 return 0;
 181         }
 182
 183         ned.nBlocks = nBlocks;
 184
 185         initialised = 1;
 186
 187         return 1;
 188 }
 189
 190 int nandemul2k_WriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_ExtendedTags *tags)
 191 {
 192         int blk;
 193         int pg;
 194         int i;
 195
 196         __u8 *x;
 197
 198
 199         blk = chunkInNAND/PAGES_PER_BLOCK;
 200         pg = chunkInNAND%PAGES_PER_BLOCK;
 201
 202
 203         if(data)
 204         {
 205                 x = ned.block[blk]->page[pg]->data;
 206
 207                 for(i = 0; i < PAGE_DATA_SIZE; i++)
 208                 {
 209                         x[i] &=data[i];
 210                 }
 211
 212                 ned.block[blk]->page[pg]->empty = 0;
 213         }
 214
 215
 216         if(tags)
 217         {
 218                 x = &ned.block[blk]->page[pg]->data[PAGE_DATA_SIZE];
 219
 220                 yaffs_PackTags2((yaffs_PackedTags2 *)x,tags);
 221
 222         }
 223
 224         if(tags || data)
 225         {
 226                 nandemul_yield(1);
 227         }
 228
 229         return YAFFS_OK;
 230 }
 231
 232
 233 int nandemul2k_ReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *tags)
 234 {
 235         int blk;
 236         int pg;
 237
 238         __u8 *x;
 239
 240
 241
 242         blk = chunkInNAND/PAGES_PER_BLOCK;
 243         pg = chunkInNAND%PAGES_PER_BLOCK;
 244
 245
 246         if(data)
 247         {
 248                 memcpy(data,ned.block[blk]->page[pg]->data,PAGE_DATA_SIZE);
 249         }
 250
 251
 252         if(tags)
 253         {
 254                 x = &ned.block[blk]->page[pg]->data[PAGE_DATA_SIZE];
 255
 256                 yaffs_UnpackTags2(tags,(yaffs_PackedTags2 *)x);
 257         }
 258
 259         return YAFFS_OK;
 260 }
 261
 262
 263 int nandemul2k_CheckChunkErased(yaffs_Device *dev,int chunkInNAND)
 264 {
 265         int blk;
 266         int pg;
 267         int i;
 268
 269
 270
 271         blk = chunkInNAND/PAGES_PER_BLOCK;
 272         pg = chunkInNAND%PAGES_PER_BLOCK;
 273
 274
 275         for(i = 0; i < PAGE_TOTAL_SIZE; i++)
 276         {
 277                 if(ned.block[blk]->page[pg]->data[i] != 0xFF)
 278                 {
 279                         return YAFFS_FAIL;
 280                 }
 281         }
 282
 283         return YAFFS_OK;
 284
 285 }
 286
 287 int nandemul2k_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
 288 {
 289
 290
 291         if(blockNumber < 0 || blockNumber >= ned.nBlocks)
 292         {
 293                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber));
 294         }
 295         else if(ned.block[blockNumber]->damaged)
 296         {
 297                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase damaged block %d\n",blockNumber));
 298         }
 299         else
 300         {
 301                 nandemul_ReallyEraseBlock(blockNumber);
 302         }
 303
 304         return YAFFS_OK;
 305 }
 306
 307 int nandemul2k_InitialiseNAND(yaffs_Device *dev)
 308 {
 309         CheckInit();
 310         return YAFFS_OK;
 311 }
 312
 313 int nandemul2k_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo)
 314 {
 315
 316         __u8 *x;
 317
 318         x = &ned.block[blockNo]->page[0]->data[PAGE_DATA_SIZE];
 319
 320         memset(x,0,sizeof(yaffs_PackedTags2));
 321
 322
 323         return YAFFS_OK;
 324
 325 }
 326
 327 int nandemul2k_QueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo, yaffs_BlockState *state, int *sequenceNumber)
 328 {
 329         yaffs_ExtendedTags tags;
 330         int chunkNo;
 331
 332         *sequenceNumber = 0;
 333
 334         chunkNo = blockNo * dev->nChunksPerBlock;
 335
 336         nandemul2k_ReadChunkWithTagsFromNAND(dev,chunkNo,NULL,&tags);
 337         if(tags.blockBad)
 338         {
 339                 *state = YAFFS_BLOCK_STATE_DEAD;
 340         }
 341         else if(!tags.chunkUsed)
 342         {
 343                 *state = YAFFS_BLOCK_STATE_EMPTY;
 344         }
 345         else if(tags.chunkUsed)
 346         {
 347                 *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
 348                 *sequenceNumber = tags.sequenceNumber;
 349         }
 350         return YAFFS_OK;
 351 }
 352
 353 int nandemul2k_GetBytesPerChunk(void) { return PAGE_DATA_SIZE;}
 354
 355 int nandemul2k_GetChunksPerBlock(void) { return PAGES_PER_BLOCK; }
 356 int nandemul2k_GetNumberOfBlocks(void) {return nandemul2k_CalcNBlocks();}
 357
 358
 359 #endif //YAFFS_RAM_ENABLED
 360