direct/yaffs_fileem.c

   1 /*
   2  * YAFFS: Yet another FFS. A NAND-flash specific file system.
   3  * yaffs_ramdisk.c: yaffs ram disk component
   4  *
   5  * Copyright (C) 2002 Aleph One Ltd.
   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
  15 // This provides a YAFFS nand emulation on a file.
  16 // THis is only intended as test code to test persistence etc.
  17
  18 const char *yaffs_flashif_c_version = "$Id: yaffs_fileem.c,v 1.1 2003-01-21 03:32:17 charles Exp $";
  19
  20
  21 #include "yportenv.h"
  22
  23 #include "yaffs_flashif.h"
  24 #include "yaffs_guts.h"
  25 #include "devextras.h"
  26
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <fcntl.h>
  30 #include <unistd.h>
  31
  32
  33
  34 #define SIZE_IN_MB 16
  35
  36 #define BLOCK_SIZE (32 * 528)
  37 #define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
  38
  39
  40
  41 typedef struct
  42 {
  43         __u8 data[528]; // Data + spare
  44 } yflash_Page;
  45
  46 typedef struct
  47 {
  48         yflash_Page page[32]; // The pages in the block
  49
  50 } yflash_Block;
  51
  52
  53
  54 typedef struct
  55 {
  56         int handle;
  57         int nBlocks;
  58 } yflash_Device;
  59
  60 static yflash_Device filedisk;
  61
  62 static int  CheckInit(yaffs_Device *dev)
  63 {
  64         static int initialised = 0;
  65
  66         int i;
  67
  68
  69         int fSize;
  70         int written;
  71
  72         yflash_Page p;
  73
  74         if(initialised)
  75         {
  76                 return YAFFS_OK;
  77         }
  78
  79         initialised = 1;
  80
  81
  82         filedisk.nBlocks = (SIZE_IN_MB * 1024 * 1024)/(16 * 1024);
  83
  84         filedisk.handle = open("yaffsemfile", O_RDWR | O_CREAT, S_IREAD | S_IWRITE);
  85
  86         if(filedisk.handle < 0)
  87         {
  88                 perror("Failed to open yaffs emulation file");
  89                 return YAFFS_FAIL;
  90         }
  91
  92
  93         fSize = lseek(filedisk.handle,0,SEEK_END);
  94
  95         if(fSize < SIZE_IN_MB * 1024 * 1024)
  96         {
  97                 printf("Creating yaffs emulation file\n");
  98
  99                 lseek(filedisk.handle,0,SEEK_SET);
 100
 101                 memset(&p,0xff,sizeof(yflash_Page));
 102
 103                 for(i = 0; i < SIZE_IN_MB * 1024 * 1024; i+= 512)
 104                 {
 105                         written = write(filedisk.handle,&p,sizeof(yflash_Page));
 106
 107                         if(written != sizeof(yflash_Page))
 108                         {
 109                                 printf("Write failed\n");
 110                                 return YAFFS_FAIL;
 111                         }
 112                 }
 113         }
 114
 115         return 1;
 116 }
 117
 118 int yflash_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_Spare *spare)
 119 {
 120         int written;
 121
 122         CheckInit(dev);
 123
 124
 125
 126         if(data)
 127         {
 128                 lseek(filedisk.handle,chunkInNAND * 528,SEEK_SET);
 129                 written = write(filedisk.handle,data,512);
 130
 131                 if(written != 512) return YAFFS_FAIL;
 132         }
 133
 134         if(spare)
 135         {
 136                 lseek(filedisk.handle,chunkInNAND * 528 + 512,SEEK_SET);
 137                 written = write(filedisk.handle,spare,16);
 138
 139                 if(written != 16) return YAFFS_FAIL;
 140         }
 141
 142
 143         return YAFFS_OK;
 144
 145 }
 146
 147
 148 int yflash_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare)
 149 {
 150         int nread;
 151
 152         CheckInit(dev);
 153
 154
 155
 156         if(data)
 157         {
 158                 lseek(filedisk.handle,chunkInNAND * 528,SEEK_SET);
 159                 nread = read(filedisk.handle,data,512);
 160
 161                 if(nread != 512) return YAFFS_FAIL;
 162         }
 163
 164         if(spare)
 165         {
 166                 lseek(filedisk.handle,chunkInNAND * 528 + 512,SEEK_SET);
 167                 nread= read(filedisk.handle,spare,16);
 168
 169                 if(nread != 16) return YAFFS_FAIL;
 170         }
 171
 172
 173         return YAFFS_OK;
 174
 175 }
 176
 177
 178 int yflash_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
 179 {
 180
 181         int i;
 182
 183         CheckInit(dev);
 184
 185         if(blockNumber < 0 || blockNumber >= filedisk.nBlocks)
 186         {
 187                 T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber));
 188                 return YAFFS_FAIL;
 189         }
 190         else
 191         {
 192
 193                 yflash_Page pg;
 194
 195                 memset(&pg,0xff,sizeof(yflash_Page));
 196
 197                 lseek(filedisk.handle, blockNumber * 32 * 528, SEEK_SET);
 198
 199                 for(i = 0; i < 32; i++)
 200                 {
 201                         write(filedisk.handle,&pg,528);
 202                 }
 203                 return YAFFS_OK;
 204         }
 205
 206 }
 207
 208 int yflash_InitialiseNAND(yaffs_Device *dev)
 209 {
 210         dev->useNANDECC = 1; // force on useNANDECC which gets faked.
 211                                                  // This saves us doing ECC checks.
 212
 213         return YAFFS_OK;
 214 }
 215
 216