yaffs_fileem2k.c

这是ARM yaffs文件系统

/*
 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2007 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <[e-mail]>
 *
 * 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 1.12 2007/02/14 01:09:06 wookey Exp $";


#include "yportenv.h"

#include "yaffs_flashif.h"
#include "yaffs_guts.h"
#include "devextras.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h> 

#include "yaffs_fileem2k.h"
#include "yaffs_packedtags2.h"

//#define SIMULATE_FAILURES

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;



#define MAX_HANDLES 20
#define BLOCKS_PER_HANDLE 8000

typedef struct
{
	int handle[MAX_HANDLES];
	int nBlocks;
} yflash_Device;

static yflash_Device filedisk;

int yaffs_testPartialWrite = 0;




static __u8 localBuffer[PAGE_SIZE];

static char *NToName(char *buf,int n)
{
	sprintf(buf,"emfile%d",n);
	return buf;
}

static char dummyBuffer[BLOCK_SIZE];

static int GetBlockFileHandle(int n)
{
	int h;
	int requiredSize;
	
	char name[40];
	NToName(name,n);
	int fSize;
	int i;
	
	h =  open(name, O_RDWR | O_CREAT, S_IREAD | S_IWRITE);
	if(h >= 0){
		fSize = lseek(h,0,SEEK_END);
		requiredSize = BLOCKS_PER_HANDLE * BLOCK_SIZE;
		if(fSize < requiredSize){
		   for(i = 0; i < BLOCKS_PER_HANDLE; i++)
		   	if(write(h,dummyBuffer,BLOCK_SIZE) != BLOCK_SIZE)
				return -1;
			
		}
	}
	
	return h;

}

static int  CheckInit(void)
{
	static int initialised = 0;
	int h;
	int i;

	
	off_t fSize;
	off_t requiredSize;
	int written;
	int blk;
	
	yflash_Page p;
	
	if(initialised) 
	{
		return YAFFS_OK;
	}

	initialised = 1;
	
	memset(dummyBuffer,0xff,sizeof(dummyBuffer));
	
	
	filedisk.nBlocks = SIZE_IN_MB * BLOCKS_PER_MB;

	for(i = 0; i <  MAX_HANDLES; i++)
		filedisk.handle[i] = -1;
	
	for(i = 0,blk = 0; blk < filedisk.nBlocks; blk+=BLOCKS_PER_HANDLE,i++)
		filedisk.handle[i] = GetBlockFileHandle(i);
	
	
	return 1;
}


int yflash_GetNumberOfBlocks(void)
{
	CheckInit();
	
	return filedisk.nBlocks;
}

int yflash_WriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_ExtendedTags *tags)
{
	int written;
	int pos;
	int h;
	int i;
	int nRead;
	int error;
	
	T(YAFFS_TRACE_MTD,(TSTR("write chunk %d data %x tags %x" TENDSTR),chunkInNAND,(unsigned)data, (unsigned)tags));

	CheckInit();
	
	
	
	if(data)
	{
		pos = (chunkInNAND % (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE)) * PAGE_SIZE;
		h = filedisk.handle[(chunkInNAND / (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE))];
		
		lseek(h,pos,SEEK_SET);
		nRead =  read(h, localBuffer,dev->nDataBytesPerChunk);
		for(i = error = 0; i < dev->nDataBytesPerChunk && !error; i++){
			if(localBuffer[i] != 0xFF){
				printf("nand simulation: chunk %d data byte %d was %0x2\n",
					chunkInNAND,i,localBuffer[i]);
				error = 1;
			}
		}
		
		for(i = 0; i < dev->nDataBytesPerChunk; i++)
		  localBuffer[i] &= data[i];
		  
		if(memcmp(localBuffer,data,dev->nDataBytesPerChunk))
			printf("nand simulator: data does not match\n");
			
		lseek(h,pos,SEEK_SET);
		written = write(h,localBuffer,dev->nDataBytesPerChunk);
		
		if(yaffs_testPartialWrite){
			close(h);
			exit(1);
		}
		
#ifdef SIMULATE_FAILURES
			if((chunkInNAND >> 6) == 100) 
			  written = 0;

			if((chunkInNAND >> 6) == 110) 
			  written = 0;
#endif


		if(written != dev->nDataBytesPerChunk) return YAFFS_FAIL;
	}
	
	if(tags)
	{
		pos = (chunkInNAND % (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE)) * PAGE_SIZE + PAGE_DATA_SIZE ;
		h = filedisk.handle[(chunkInNAND / (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE))];
		
		lseek(h,pos,SEEK_SET);

		if( 0 && dev->isYaffs2)
		{
			
			written = write(h,tags,sizeof(yaffs_ExtendedTags));
			if(written != sizeof(yaffs_ExtendedTags)) return YAFFS_FAIL;
		}
		else
		{
			yaffs_PackedTags2 pt;
			yaffs_PackTags2(&pt,tags);
			__u8 * ptab = (__u8 *)&pt;

			nRead = read(h,localBuffer,sizeof(pt));
			for(i = error = 0; i < sizeof(pt) && !error; i++){
				if(localBuffer[i] != 0xFF){
					printf("nand simulation: chunk %d oob byte %d was %0x2\n",
						chunkInNAND,i,localBuffer[i]);
						error = 1;
				}
			}
		
			for(i = 0; i < sizeof(pt); i++)
			  localBuffer[i] &= ptab[i];
			 
			if(memcmp(localBuffer,&pt,sizeof(pt)))
				printf("nand sim: tags corruption\n");
				
			lseek(h,pos,SEEK_SET);
			
			written = write(h,localBuffer,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;
}


static int fail300 = 1;
static int fail320 = 1;

static int failRead10 = 2;

int yflash_ReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *tags)
{
	int nread;
	int pos;
	int h;
	
	T(YAFFS_TRACE_MTD,(TSTR("read chunk %d data %x tags %x" TENDSTR),chunkInNAND,(unsigned)data, (unsigned)tags));
	
	CheckInit();
	
	
	
	if(data)
	{

		pos = (chunkInNAND % (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE)) * PAGE_SIZE;
		h = filedisk.handle[(chunkInNAND / (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE))];		
		lseek(h,pos,SEEK_SET);
		nread = read(h,data,dev->nDataBytesPerChunk);
		
		
		if(nread != dev->nDataBytesPerChunk) return YAFFS_FAIL;
	}
	
	if(tags)
	{
		pos = (chunkInNAND % (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE)) * PAGE_SIZE + PAGE_DATA_SIZE;
		h = filedisk.handle[(chunkInNAND / (PAGES_PER_BLOCK * BLOCKS_PER_HANDLE))];		
		lseek(h,pos,SEEK_SET);

		if(0 && dev->isYaffs2)
		{
			nread= read(h,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_PackedTags2 pt;
			nread= read(h,&pt,sizeof(pt));
			yaffs_UnpackTags2(tags,&pt);
#ifdef SIMULATE_FAILURES
			if((chunkInNAND >> 6) == 100) {
			    if(fail300 && tags->eccResult == YAFFS_ECC_RESULT_NO_ERROR){
			       tags->eccResult = YAFFS_ECC_RESULT_FIXED;
			       fail300 = 0;
			    }
			    
			}
			if((chunkInNAND >> 6) == 110) {
			    if(fail320 && tags->eccResult == YAFFS_ECC_RESULT_NO_ERROR){
			       tags->eccResult = YAFFS_ECC_RESULT_FIXED;
			       fail320 = 0;
			    }
			}
#endif
			if(failRead10>0 && chunkInNAND == 10){
				failRead10--;
				nread = 0;
			}
			
			if(nread != sizeof(pt)) return YAFFS_FAIL;
		}
	}
	

	return YAFFS_OK;	

}


int yflash_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo)
{
	int written;
	int h;
	
	yaffs_PackedTags2 pt;

	CheckInit();
	
	memset(&pt,0,sizeof(pt));
	h = filedisk.handle[(blockNo / ( BLOCKS_PER_HANDLE))];
	lseek(h,((blockNo % BLOCKS_PER_HANDLE) * dev->nChunksPerBlock) * PAGE_SIZE + PAGE_DATA_SIZE,SEEK_SET);
	written = write(h,&pt,sizeof(pt));
		
	if(written != sizeof(pt)) return YAFFS_FAIL;
	
	
	return YAFFS_OK;
	
}

int yflash_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
{

	int i;
	int h;
		
	CheckInit();
	
	printf("erase block %d\n",blockNumber);
	
	if(blockNumber == 320)
		fail320 = 1;
	
	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);
		

		h = filedisk.handle[(blockNumber / ( BLOCKS_PER_HANDLE))];
		lseek(h,((blockNumber % BLOCKS_PER_HANDLE) * dev->nChunksPerBlock) * PAGE_SIZE,SEEK_SET);		
		for(i = 0; i < dev->nChunksPerBlock; i++)
		{
			write(h,pg,PAGE_SIZE);
		}
		pos = lseek(h, 0,SEEK_CUR);
		
		return YAFFS_OK;
	}
	
}

int yflash_InitialiseNAND(yaffs_Device *dev)
{
	CheckInit();
	
	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;
}