www.pudn.com > yaffs2.zip > yaffs_fileem2k.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 for emulating 2kB pages. 
// THis is only intended as test code to test persistence etc. 
 
const char *yaffs_flashif_c_version = "$Id: yaffs_fileem2k.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   
 
#include "yaffs_fileem2k.h" 
#include "yaffs_packedtags.h" 
 
 
 
typedef struct  
{ 
	__u8 data[PAGE_SIZE]; // Data + spare 
} yflash_Page; 
 
typedef struct 
{ 
	yflash_Page page[PAGES_PER_BLOCK]; // 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 * BLOCKS_PER_MB; 
	 
	filedisk.handle = open("yaffsemfile2k", 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 < filedisk.nBlocks * BLOCK_SIZE) 
	{ 
		printf("Creating yaffs emulation file\n"); 
		 
		lseek(filedisk.handle,0,SEEK_SET); 
		 
		memset(&p,0xff,sizeof(yflash_Page)); 
		 
		for(i = 0; i <  filedisk.nBlocks * BLOCK_SIZE; i+= PAGE_SIZE) 
		{ 
			written = write(filedisk.handle,&p,sizeof(yflash_Page)); 
			 
			if(written != sizeof(yflash_Page)) 
			{ 
				printf("Write failed\n"); 
				return YAFFS_FAIL; 
			} 
		}		 
	} 
	 
	return 1; 
} 
 
int yflash_WriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_ExtendedTags *tags) 
{ 
	int written; 
	int pos; 
 
	CheckInit(dev); 
	 
	 
	 
	if(data) 
	{ 
		pos = chunkInNAND * PAGE_SIZE; 
		lseek(filedisk.handle,pos,SEEK_SET); 
		written = write(filedisk.handle,data,dev->nBytesPerChunk); 
		 
		if(written != dev->nBytesPerChunk) return YAFFS_FAIL; 
	} 
	 
	if(tags) 
	{ 
		pos = chunkInNAND * PAGE_SIZE + PAGE_DATA_SIZE; 
		lseek(filedisk.handle,pos,SEEK_SET); 
		if(dev->isYaffs2) 
		{ 
			 
			written = write(filedisk.handle,tags,sizeof(yaffs_ExtendedTags)); 
			if(written != sizeof(yaffs_ExtendedTags)) return YAFFS_FAIL; 
		} 
		else 
		{ 
			yaffs_PackedTags pt; 
			yaffs_PackTags(&pt,tags); 
 
			written = write(filedisk.handle,&pt,sizeof(pt)); 
			if(written != sizeof(pt)) return YAFFS_FAIL; 
		} 
	} 
	 
 
	return YAFFS_OK;	 
 
} 
 
int yflash_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo) 
{ 
	int written; 
	 
	yaffs_PackedTags pt; 
 
	CheckInit(dev); 
	 
	memset(&pt,0,sizeof(pt)); 
	lseek(filedisk.handle,(blockNo * dev->nChunksPerBlock) * PAGE_SIZE + PAGE_DATA_SIZE,SEEK_SET); 
	written = write(filedisk.handle,&pt,sizeof(pt)); 
		 
	if(written != sizeof(pt)) return YAFFS_FAIL; 
	 
	 
	return YAFFS_OK; 
	 
} 
 
int yaffs_CheckAllFF(const __u8 *ptr, int n) 
{ 
	while(n) 
	{ 
		n--; 
		if(*ptr!=0xFF) return 0; 
		ptr++; 
	} 
	return 1; 
} 
 
 
int yflash_ReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *tags) 
{ 
	int nread; 
	int pos; 
 
	CheckInit(dev); 
	 
	 
	 
	if(data) 
	{ 
		pos = chunkInNAND * PAGE_SIZE; 
		lseek(filedisk.handle,pos,SEEK_SET); 
		nread = read(filedisk.handle,data,dev->nBytesPerChunk); 
		 
		if(nread != dev->nBytesPerChunk) return YAFFS_FAIL; 
	} 
	 
	if(tags) 
	{ 
		pos = chunkInNAND * PAGE_SIZE + PAGE_DATA_SIZE; 
		lseek(filedisk.handle,pos,SEEK_SET); 
		if(dev->isYaffs2) 
		{ 
			nread= read(filedisk.handle,tags,sizeof(yaffs_ExtendedTags)); 
			if(nread != sizeof(yaffs_ExtendedTags)) return YAFFS_FAIL; 
			if(yaffs_CheckAllFF((__u8 *)tags,sizeof(yaffs_ExtendedTags))) 
			{ 
				yaffs_InitialiseTags(tags); 
			} 
			else 
			{ 
				tags->chunkUsed = 1; 
			} 
		} 
		else 
		{ 
			yaffs_PackedTags pt; 
			nread= read(filedisk.handle,&pt,sizeof(pt)); 
			yaffs_UnpackTags(tags,&pt); 
			if(nread != sizeof(pt)) 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 
	{ 
	 
		__u8 pg[PAGE_SIZE]; 
		int syz = PAGE_SIZE; 
		int pos; 
		 
		memset(pg,0xff,syz); 
		 
		pos = lseek(filedisk.handle, blockNumber * dev->nChunksPerBlock * PAGE_SIZE, SEEK_SET); 
		 
		for(i = 0; i < dev->nChunksPerBlock; i++) 
		{ 
			write(filedisk.handle,pg,PAGE_SIZE); 
		} 
		pos = lseek(filedisk.handle, 0,SEEK_CUR); 
		 
		return YAFFS_OK; 
	} 
	 
} 
 
int yflash_InitialiseNAND(yaffs_Device *dev) 
{ 
	CheckInit(dev); 
	 
	return YAFFS_OK; 
} 
 
 
 
 
int yflash_QueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo, yaffs_BlockState *state, int *sequenceNumber) 
{ 
	yaffs_ExtendedTags tags; 
	int chunkNo; 
 
	*sequenceNumber = 0; 
	 
	chunkNo = blockNo * dev->nChunksPerBlock; 
	 
	yflash_ReadChunkWithTagsFromNAND(dev,chunkNo,NULL,&tags); 
	if(tags.blockBad) 
	{ 
		*state = YAFFS_BLOCK_STATE_DEAD; 
	} 
	else if(!tags.chunkUsed) 
	{ 
		*state = YAFFS_BLOCK_STATE_EMPTY; 
	} 
	else if(tags.chunkUsed) 
	{ 
		*state = YAFFS_BLOCK_STATE_NEEDS_SCANNING; 
		*sequenceNumber = tags.sequenceNumber; 
	} 
	return YAFFS_OK; 
}