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 1.1 2004-12-17 04:39:04 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_nandemul.h"
  29 #include "yaffs_guts.h"
  30 #include "yaffsinterface.h"
  31 #include "devextras.h"
  32
  33
  34 #define EM_SIZE_IN_MEG 2
  35
  36 #define BLOCK_SIZE (32 * 528)
  37 #define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
  38 #define FILE_SIZE_IN_BLOCKS (FILE_SIZE_IN_MEG * BLOCKS_PER_MEG)
  39 #define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * BLOCK_SIZE)
  40
  41
  42
  43 #define DEFAULT_SIZE_IN_MB 2
  44
  45 typedef struct
  46 {
  47         __u8 data[528]; // Data + spare
  48         int count[3];   // The programming count for each area of
  49                         // the page (0..255,256..511,512..527
  50         int empty;      // is this empty?
  51 } nandemul_Page;
  52
  53 typedef struct
  54 {
  55         nandemul_Page page[32]; // The pages in the block
  56         __u8 damaged;           // Is the block damaged?
  57
  58 } nandemul_Block;
  59
  60
  61
  62 typedef struct
  63 {
  64         nandemul_Block **block;
  65         int nBlocks;
  66 } nandemul_Device;
  67
  68 static nandemul_Device ned;
  69
  70 static int sizeInMB = DEFAULT_SIZE_IN_MB;
  71
  72
  73 static void nandemul_yield(int n)
  74 {
  75 #ifdef __KERNEL__
  76         if(n > 0) schedule_timeout(n);
  77 #endif
  78
  79 }
  80
  81
  82 static void nandemul_ReallyEraseBlock(int blockNumber)
  83 {
  84         int i;
  85
  86         nandemul_Block *theBlock = ned.block[blockNumber];
  87
  88         for(i = 0; i < 32; i++)
  89         {
  90                 memset(theBlock->page[i].data,0xff,528);
  91                 theBlock->page[i].count[0] = 0;
  92                 theBlock->page[i].count[1] = 0;
  93                 theBlock->page[i].count[2] = 0;
  94                 theBlock->page[i].empty = 1;
  95                 nandemul_yield(2);
  96         }
  97
  98 }
  99
 100
 101 int nandemul_CalcNBlocks(void)
 102 {
 103         switch(sizeInMB)
 104         {
 105                 case 8:
 106                 case 16:
 107                 case 32:
 108                 case 64:
 109                 case 128:
 110                 case 256:
 111                 case 512:
 112                         break;
 113                 default:
 114                         sizeInMB = DEFAULT_SIZE_IN_MB;
 115         }
 116         return sizeInMB * 64;
 117 }
 118
 119
 120
 121 static int  CheckInit(void)
 122 {
 123         static int initialised = 0;
 124
 125         int i;
 126         int fail = 0;
 127         int nBlocks;
 128         int nAllocated = 0;
 129
 130         if(initialised)
 131         {
 132                 return YAFFS_OK;
 133         }
 134
 135
 136         nBlocks = nandemul_CalcNBlocks();
 137
 138         ned.block = YMALLOC(sizeof(nandemul_Block *) * nBlocks);
 139
 140         if(!ned.block) return 0;
 141
 142         for(i=0; i <nBlocks; i++)
 143         {
 144                 ned.block[i] = NULL;
 145         }
 146
 147         for(i=0; i <nBlocks && !fail; i++)
 148         {
 149                 if((ned.block[i] = YMALLOC(sizeof(nandemul_Block))) == 0)
 150                 {
 151                         fail = 1;
 152                 }
 153                 else
 154                 {
 155                         nandemul_ReallyEraseBlock(i);
 156                         ned.block[i]->damaged = 0;
 157                         nAllocated++;
 158                 }
 159         }
 160
 161         if(fail)
 162         {
 163                 for(i = 0; i < nAllocated; i++)
 164                 {
 165                         YFREE(ned.block[i]);
 166                 }
 167                 YFREE(ned.block);
 168
 169                 T(YAFFS_TRACE_ALWAYS,("Allocation failed, could only allocate %dMB of %dMB requested.\n",
 170                    nAllocated/64,sizeInMB));
 171                 return 0;
 172         }
 173
 174         ned.nBlocks = nBlocks;
 175
 176         initialised = 1;
 177
 178         return 1;
 179 }
 180
 181 int nandemul_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_Spare *spare)
 182 {
 183         int blk;
 184         int pg;
 185         int i;
 186
 187         __u8 *x;
 188
 189         __u8 *spareAsBytes = (__u8 *)spare;
 190
 191
 192         CheckInit();
 193
 194         blk = chunkInNAND/32;
 195         pg = chunkInNAND%32;
 196
 197
 198         if(data)
 199         {
 200                 x = ned.block[blk]->page[pg].data;
 201
 202                 for(i = 0; i < 512; i++)
 203                 {
 204                         x[i] &=data[i];
 205                 }
 206
 207                 ned.block[blk]->page[pg].count[0]++;
 208                 ned.block[blk]->page[pg].count[1]++;
 209                 ned.block[blk]->page[pg].empty = 0;
 210         }
 211
 212
 213         if(spare)
 214         {
 215                 x = &ned.block[blk]->page[pg].data[512];
 216
 217                 for(i = 0; i < 16; i++)
 218                 {
 219                         x[i] &=spareAsBytes[i];
 220                 }
 221                 ned.block[blk]->page[pg].count[2]++;
 222         }
 223
 224         if(spare || data)
 225         {
 226                 nandemul_yield(1);
 227         }
 228
 229         return YAFFS_OK;
 230 }
 231
 232
 233 int nandemul_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare)
 234 {
 235         int blk;
 236         int pg;
 237
 238
 239         CheckInit();
 240
 241         blk = chunkInNAND/32;
 242         pg = chunkInNAND%32;
 243
 244
 245         if(data)
 246         {
 247                 memcpy(data,ned.block[blk]->page[pg].data,512);
 248         }
 249
 250
 251         if(spare)
 252         {
 253                 memcpy(spare,&ned.block[blk]->page[pg].data[512],16);
 254         }
 255
 256         return YAFFS_OK;
 257 }
 258
 259
 260 int nandemul_CheckChunkErased(yaffs_Device *dev,int chunkInNAND)
 261 {
 262         int blk;
 263         int pg;
 264         int i;
 265
 266
 267         CheckInit();
 268
 269         blk = chunkInNAND/32;
 270         pg = chunkInNAND%32;
 271
 272
 273         for(i = 0; i < 528; i++)
 274         {
 275                 if(ned.block[blk]->page[pg].data[i] != 0xFF)
 276                 {
 277                         return YAFFS_FAIL;
 278                 }
 279         }
 280
 281         return YAFFS_OK;
 282
 283 }
 284
 285 int nandemul_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
 286 {
 287
 288         CheckInit();
 289
 290         if(blockNumber < 0 || blockNumber >= ned.nBlocks)
 291         {
 292                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber));
 293         }
 294         else if(ned.block[blockNumber]->damaged)
 295         {
 296                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase damaged block %d\n",blockNumber));
 297         }
 298         else
 299         {
 300                 nandemul_ReallyEraseBlock(blockNumber);
 301         }
 302
 303         return YAFFS_OK;
 304 }
 305
 306 int nandemul_InitialiseNAND(yaffs_Device *dev)
 307 {
 308         return YAFFS_OK;
 309 }
 310
 311 #endif //YAFFS_RAM_ENABLED
 312