yaffs_fileem.c

   1 /*
   2  * YAFFS: Yet another FFS. A NAND-flash specific file system.
   3  * yaffs_fileem.c  NAND emulation on top of files
   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_fileem.c
  16
  17 #include "yaffs_nandif.h"
  18 #include "yaffs_guts.h"
  19 #include "yaffsinterface.h"
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <string.h>
  28
  29 #define FILE_SIZE_IN_MEG 2
  30
  31 #define BLOCK_SIZE (32 * 528)
  32 #define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
  33 #define FILE_SIZE_IN_BLOCKS (FILE_SIZE_IN_MEG * BLOCKS_PER_MEG)
  34 #define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * BLOCK_SIZE)
  35
  36
  37 static int h;
  38 static __u8 ffChunk[528];
  39
  40
  41
  42 static void  CheckInit(void)
  43 {
  44         static int initialised = 0;
  45
  46         int length;
  47
  48
  49         if(!initialised)
  50         {
  51                 memset(ffChunk,0xFF,528);
  52
  53                 h = open("yaffs-em-file" , O_RDWR | O_CREAT, S_IREAD | S_IWRITE);
  54                 if(h < 0)
  55                 {
  56                         perror("Fatal error opening yaffs emulation file");
  57                         exit(1);
  58                 }
  59                 initialised = 1;
  60
  61                 length = lseek(h,0,SEEK_END);
  62                 if(length !=  FILE_SIZE_IN_BYTES)
  63                 {
  64                         // Create file contents
  65                         int i;
  66
  67                         printf("Creating emulation file...\n");
  68                         for(i = 0; i < FILE_SIZE_IN_BLOCKS; i++)
  69                         {
  70                                 yaffs_EraseBlockInNAND(i);
  71                         }
  72                 }
  73         }
  74 }
  75
  76 int yaffs_WriteChunkToNAND(int chunkInNAND,__u8 *data, yaffs_Spare *spare)
  77 {
  78         int pos;
  79
  80         pos = chunkInNAND * 528;
  81
  82         CheckInit();
  83
  84
  85         if(data)
  86         {
  87                 lseek(h,pos,SEEK_SET);
  88                 write(h,data,512);
  89         }
  90
  91         pos += 512;
  92
  93         if(spare)
  94         {
  95                 lseek(h,pos,SEEK_SET);
  96                 write(h,spare,16);
  97         }
  98
  99         return YAFFS_OK;
 100 }
 101
 102
 103 int yaffs_ReadChunkFromNAND(int chunkInNAND, __u8 *data, yaffs_Spare *spare)
 104 {
 105         int pos;
 106
 107         pos = chunkInNAND * 528;
 108
 109
 110         CheckInit();
 111
 112         if(data)
 113         {
 114                 lseek(h,pos,SEEK_SET);
 115                 read(h,data,512);
 116         }
 117
 118         pos += 512;
 119
 120         if(spare)
 121         {
 122                 lseek(h,pos,SEEK_SET);
 123                 read(h,spare,16);
 124         }
 125
 126         return YAFFS_OK;
 127 }
 128
 129
 130 int yaffs_EraseBlockInNAND(int blockInNAND)
 131 {
 132         int i;
 133
 134         CheckInit();
 135
 136         printf("Erasing block %d\n",blockInNAND);
 137
 138         lseek(h,blockInNAND * BLOCK_SIZE,SEEK_SET);
 139         for(i = 0; i < 32; i++)
 140         {
 141                 write(h,ffChunk,528);
 142         }
 143         return YAFFS_OK;
 144 }
 145