yaffs_ramem.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_ramem.c
  16  // Since this creates the RAM block at start up it is pretty useless for testing the scanner.
  17
  18 const char *yaffs_ramem_c_version = "$Id: yaffs_ramem.c,v 1.3 2005-07-29 19:57:38 luc Exp $";
  19
  20 #ifndef __KERNEL__
  21 #define CONFIG_YAFFS_RAM_ENABLED
  22 #else
  23 #include <linux/config.h>
  24 #endif
  25
  26 #ifdef CONFIG_YAFFS_RAM_ENABLED
  27
  28 #include "yportenv.h"
  29
  30 #include "yaffs_nandemul.h"
  31 #include "yaffs_guts.h"
  32 #include "yaffsinterface.h"
  33 #include "devextras.h"
  34
  35
  36 #define EM_SIZE_IN_MEG 2
  37
  38 #define YAFFS_BLOCK_SIZE (32 * 528)
  39 #define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
  40 #define FILE_SIZE_IN_BLOCKS (FILE_SIZE_IN_MEG * BLOCKS_PER_MEG)
  41 #define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * YAFFS_BLOCK_SIZE)
  42
  43
  44
  45 #define DEFAULT_SIZE_IN_MB 2
  46
  47 typedef struct
  48 {
  49         __u8 data[528]; // Data + spare
  50         int count[3];   // The programming count for each area of
  51                         // the page (0..255,256..511,512..527
  52         int empty;      // is this empty?
  53 } nandemul_Page;
  54
  55 typedef struct
  56 {
  57         nandemul_Page page[32]; // The pages in the block
  58         __u8 damaged;           // Is the block damaged?
  59
  60 } nandemul_Block;
  61
  62
  63
  64 typedef struct
  65 {
  66         nandemul_Block **block;
  67         int nBlocks;
  68 } nandemul_Device;
  69
  70 static nandemul_Device ned;
  71
  72 static int sizeInMB = DEFAULT_SIZE_IN_MB;
  73
  74
  75 static void nandemul_yield(int n)
  76 {
  77 #ifdef __KERNEL__
  78         if(n > 0) schedule_timeout(n);
  79 #endif
  80
  81 }
  82
  83
  84 static void nandemul_ReallyEraseBlock(int blockNumber)
  85 {
  86         int i;
  87
  88         nandemul_Block *theBlock = ned.block[blockNumber];
  89
  90         for(i = 0; i < 32; i++)
  91         {
  92                 memset(theBlock->page[i].data,0xff,528);
  93                 theBlock->page[i].count[0] = 0;
  94                 theBlock->page[i].count[1] = 0;
  95                 theBlock->page[i].count[2] = 0;
  96                 theBlock->page[i].empty = 1;
  97                 nandemul_yield(2);
  98         }
  99
 100 }
 101
 102
 103 int nandemul_CalcNBlocks(void)
 104 {
 105         switch(sizeInMB)
 106         {
 107                 case 8:
 108                 case 16:
 109                 case 32:
 110                 case 64:
 111                 case 128:
 112                 case 256:
 113                 case 512:
 114                         break;
 115                 default:
 116                         sizeInMB = DEFAULT_SIZE_IN_MB;
 117         }
 118         return sizeInMB * 64;
 119 }
 120
 121
 122
 123 static int  CheckInit(void)
 124 {
 125         static int initialised = 0;
 126
 127         int i;
 128         int fail = 0;
 129         int nBlocks;
 130         int nAllocated = 0;
 131
 132         if(initialised)
 133         {
 134                 return YAFFS_OK;
 135         }
 136
 137
 138         nBlocks = nandemul_CalcNBlocks();
 139
 140         ned.block = YMALLOC(sizeof(nandemul_Block *) * nBlocks);
 141
 142         if(!ned.block) return 0;
 143
 144         for(i=0; i <nBlocks; i++)
 145         {
 146                 ned.block[i] = NULL;
 147         }
 148
 149         for(i=0; i <nBlocks && !fail; i++)
 150         {
 151                 if((ned.block[i] = YMALLOC(sizeof(nandemul_Block))) == 0)
 152                 {
 153                         fail = 1;
 154                 }
 155                 else
 156                 {
 157                         nandemul_ReallyEraseBlock(i);
 158                         ned.block[i]->damaged = 0;
 159                         nAllocated++;
 160                 }
 161         }
 162
 163         if(fail)
 164         {
 165                 for(i = 0; i < nAllocated; i++)
 166                 {
 167                         YFREE(ned.block[i]);
 168                 }
 169                 YFREE(ned.block);
 170
 171                 T(YAFFS_TRACE_ALWAYS,("Allocation failed, could only allocate %dMB of %dMB requested.\n",
 172                    nAllocated/64,sizeInMB));
 173                 return 0;
 174         }
 175
 176         ned.nBlocks = nBlocks;
 177
 178         initialised = 1;
 179
 180         return 1;
 181 }
 182
 183 int nandemul_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_Spare *spare)
 184 {
 185         int blk;
 186         int pg;
 187         int i;
 188
 189         __u8 *x;
 190
 191         __u8 *spareAsBytes = (__u8 *)spare;
 192
 193
 194         CheckInit();
 195
 196         blk = chunkInNAND/32;
 197         pg = chunkInNAND%32;
 198
 199
 200         if(data)
 201         {
 202                 x = ned.block[blk]->page[pg].data;
 203
 204                 for(i = 0; i < 512; i++)
 205                 {
 206                         x[i] &=data[i];
 207                 }
 208
 209                 ned.block[blk]->page[pg].count[0]++;
 210                 ned.block[blk]->page[pg].count[1]++;
 211                 ned.block[blk]->page[pg].empty = 0;
 212         }
 213
 214
 215         if(spare)
 216         {
 217                 x = &ned.block[blk]->page[pg].data[512];
 218
 219                 for(i = 0; i < 16; i++)
 220                 {
 221                         x[i] &=spareAsBytes[i];
 222                 }
 223                 ned.block[blk]->page[pg].count[2]++;
 224         }
 225
 226         if(spare || data)
 227         {
 228                 nandemul_yield(1);
 229         }
 230
 231         return YAFFS_OK;
 232 }
 233
 234
 235 int nandemul_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare)
 236 {
 237         int blk;
 238         int pg;
 239
 240
 241         CheckInit();
 242
 243         blk = chunkInNAND/32;
 244         pg = chunkInNAND%32;
 245
 246
 247         if(data)
 248         {
 249                 memcpy(data,ned.block[blk]->page[pg].data,512);
 250         }
 251
 252
 253         if(spare)
 254         {
 255                 memcpy(spare,&ned.block[blk]->page[pg].data[512],16);
 256         }
 257
 258         return YAFFS_OK;
 259 }
 260
 261
 262 int nandemul_CheckChunkErased(yaffs_Device *dev,int chunkInNAND)
 263 {
 264         int blk;
 265         int pg;
 266         int i;
 267
 268
 269         CheckInit();
 270
 271         blk = chunkInNAND/32;
 272         pg = chunkInNAND%32;
 273
 274
 275         for(i = 0; i < 528; 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 nandemul_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
 288 {
 289
 290         CheckInit();
 291
 292         if(blockNumber < 0 || blockNumber >= ned.nBlocks)
 293         {
 294                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber));
 295         }
 296         else if(ned.block[blockNumber]->damaged)
 297         {
 298                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase damaged block %d\n",blockNumber));
 299         }
 300         else
 301         {
 302                 nandemul_ReallyEraseBlock(blockNumber);
 303         }
 304
 305         return YAFFS_OK;
 306 }
 307
 308 int nandemul_InitialiseNAND(yaffs_Device *dev)
 309 {
 310         return YAFFS_OK;
 311 }
 312
 313 #endif //YAFFS_RAM_ENABLED
 314