www.pudn.com > yaffs2.zip > yaffs_fileem.c

/* 
 * YAFFS: Yet another FFS. A NAND-flash specific file system.  
 * yaffs_ramdisk.c: yaffs ram disk component 
 * 
 * Copyright (C) 2002 Aleph One Ltd. 
 * 
 * Created by Charles Manning  
 * 
 * This program is free software; you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License version 2 as 
 * published by the Free Software Foundation. 
 * 
 */ 
 
// This provides a YAFFS nand emulation on a file. 
// THis is only intended as test code to test persistence etc. 
 
const char *yaffs_flashif_c_version = "$Id: yaffs_fileem.c,v 1.1 2004/11/03 08:29:28 charles Exp $"; 
 
 
#include "yportenv.h" 
 
#include "yaffs_flashif.h" 
#include "yaffs_guts.h" 
 
#include "devextras.h" 
 
#include  
#include  
#include  
#include   
 
 
 
#define SIZE_IN_MB 16 
 
#define BLOCK_SIZE (32 * 528) 
#define BLOCKS_PER_MEG ((1024*1024)/(32 * 512)) 
 
 
 
typedef struct  
{ 
	__u8 data[528]; // Data + spare 
} yflash_Page; 
 
typedef struct 
{ 
	yflash_Page page[32]; // The pages in the block 
	 
} yflash_Block; 
 
 
 
typedef struct 
{ 
	int handle; 
	int nBlocks; 
} yflash_Device; 
 
static yflash_Device filedisk; 
 
static int  CheckInit(yaffs_Device *dev) 
{ 
	static int initialised = 0; 
	 
	int i; 
 
	 
	int fSize; 
	int written; 
	 
	yflash_Page p; 
	 
	if(initialised)  
	{ 
		return YAFFS_OK; 
	} 
 
	initialised = 1; 
	 
	 
	filedisk.nBlocks = (SIZE_IN_MB * 1024 * 1024)/(16 * 1024); 
	 
	filedisk.handle = open("yaffsemfile", O_RDWR | O_CREAT, S_IREAD | S_IWRITE); 
	 
	if(filedisk.handle < 0) 
	{ 
		perror("Failed to open yaffs emulation file"); 
		return YAFFS_FAIL; 
	} 
	 
	 
	fSize = lseek(filedisk.handle,0,SEEK_END); 
	 
	if(fSize < SIZE_IN_MB * 1024 * 1024) 
	{ 
		printf("Creating yaffs emulation file\n"); 
		 
		lseek(filedisk.handle,0,SEEK_SET); 
		 
		memset(&p,0xff,sizeof(yflash_Page)); 
		 
		for(i = 0; i < SIZE_IN_MB * 1024 * 1024; i+= 512) 
		{ 
			written = write(filedisk.handle,&p,sizeof(yflash_Page)); 
			 
			if(written != sizeof(yflash_Page)) 
			{ 
				printf("Write failed\n"); 
				return YAFFS_FAIL; 
			} 
		}		 
	} 
	 
	return 1; 
} 
 
int yflash_WriteChunkToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_Spare *spare) 
{ 
	int written; 
 
	CheckInit(dev); 
	 
	 
	 
	if(data) 
	{ 
		lseek(filedisk.handle,chunkInNAND * 528,SEEK_SET); 
		written = write(filedisk.handle,data,512); 
		 
		if(written != 512) return YAFFS_FAIL; 
	} 
	 
	if(spare) 
	{ 
		lseek(filedisk.handle,chunkInNAND * 528 + 512,SEEK_SET); 
		written = write(filedisk.handle,spare,16); 
		 
		if(written != 16) return YAFFS_FAIL; 
	} 
	 
 
	return YAFFS_OK;	 
 
} 
 
 
int yflash_ReadChunkFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_Spare *spare) 
{ 
	int nread; 
 
	CheckInit(dev); 
	 
	 
	 
	if(data) 
	{ 
		lseek(filedisk.handle,chunkInNAND * 528,SEEK_SET); 
		nread = read(filedisk.handle,data,512); 
		 
		if(nread != 512) return YAFFS_FAIL; 
	} 
	 
	if(spare) 
	{ 
		lseek(filedisk.handle,chunkInNAND * 528 + 512,SEEK_SET); 
		nread= read(filedisk.handle,spare,16); 
		 
		if(nread != 16) return YAFFS_FAIL; 
	} 
	 
 
	return YAFFS_OK;	 
 
} 
 
 
int yflash_EraseBlockInNAND(yaffs_Device *dev, int blockNumber) 
{ 
 
	int i; 
		 
	CheckInit(dev); 
	 
	if(blockNumber < 0 || blockNumber >= filedisk.nBlocks) 
	{ 
		T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber)); 
		return YAFFS_FAIL; 
	} 
	else 
	{ 
	 
		yflash_Page pg; 
		 
		memset(&pg,0xff,sizeof(yflash_Page)); 
		 
		lseek(filedisk.handle, blockNumber * 32 * 528, SEEK_SET); 
		 
		for(i = 0; i < 32; i++) 
		{ 
			write(filedisk.handle,&pg,528); 
		} 
		return YAFFS_OK; 
	} 
	 
} 
 
int yflash_InitialiseNAND(yaffs_Device *dev) 
{ 
	dev->useNANDECC = 1; // force on useNANDECC which gets faked.  
						 // This saves us doing ECC checks. 
	 
	return YAFFS_OK; 
}