www.pudn.com > yaffs2.zip > yaffs_ramdisk.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 rma disk under yaffs. 
// NB this is not intended for NAND emulation. 
// Use this with dev->useNANDECC enabled, then ECC overheads are not required. 
 
const char *yaffs_ramdisk_c_version = "$Id: yaffs_ramdisk.c,v 1.1 2004/11/03 08:29:28 charles Exp $"; 
 
 
#include "yportenv.h" 
 
#include "yaffs_ramdisk.h" 
#include "yaffs_guts.h" 
#include "devextras.h" 
#include "yaffs_packedtags.h" 
 
 
 
#define SIZE_IN_MB 2 
 
#define BLOCK_SIZE (32 * 528) 
#define BLOCKS_PER_MEG ((1024*1024)/(32 * 512)) 
 
 
 
 
 
typedef struct  
{ 
	__u8 data[528]; // Data + spare 
} yramdisk_Page; 
 
typedef struct 
{ 
	yramdisk_Page page[32]; // The pages in the block 
	 
} yramdisk_Block; 
 
 
 
typedef struct 
{ 
	yramdisk_Block **block; 
	int nBlocks; 
} yramdisk_Device; 
 
static yramdisk_Device ramdisk; 
 
static int  CheckInit(yaffs_Device *dev) 
{ 
	static int initialised = 0; 
	 
	int i; 
	int fail = 0; 
	//int nBlocks;  
	int nAllocated = 0; 
	 
	if(initialised)  
	{ 
		return YAFFS_OK; 
	} 
 
	initialised = 1; 
	 
	 
	ramdisk.nBlocks = (SIZE_IN_MB * 1024 * 1024)/(16 * 1024); 
	 
	ramdisk.block = YMALLOC(sizeof(yramdisk_Block *) * ramdisk.nBlocks); 
	 
	if(!ramdisk.block) return 0; 
	 
	for(i=0; i page[pg].data,data,512); 
	} 
	 
	 
	if(tags) 
	{ 
		yaffs_PackedTags pt; 
		 
		yaffs_PackTags(&pt,tags); 
		memcpy(&ramdisk.block[blk]->page[pg].data[512],&pt,sizeof(pt)); 
	} 
 
	return YAFFS_OK;	 
 
} 
 
 
int yramdisk_ReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *tags) 
{ 
	int blk; 
	int pg; 
 
	 
	CheckInit(dev); 
	 
	blk = chunkInNAND/32; 
	pg = chunkInNAND%32; 
	 
	 
	if(data) 
	{ 
		memcpy(data,ramdisk.block[blk]->page[pg].data,512); 
	} 
	 
	 
	if(tags) 
	{ 
		yaffs_PackedTags pt; 
		 
		memcpy(&pt,&ramdisk.block[blk]->page[pg].data[512],sizeof(pt)); 
		yaffs_UnpackTags(tags,&pt); 
		 
	} 
 
	return YAFFS_OK; 
} 
 
 
int yramdisk_CheckChunkErased(yaffs_Device *dev,int chunkInNAND) 
{ 
	int blk; 
	int pg; 
	int i; 
 
	 
	CheckInit(dev); 
	 
	blk = chunkInNAND/32; 
	pg = chunkInNAND%32; 
	 
	 
	for(i = 0; i < 528; i++) 
	{ 
		if(ramdisk.block[blk]->page[pg].data[i] != 0xFF) 
		{ 
			return YAFFS_FAIL; 
		} 
	} 
 
	return YAFFS_OK; 
 
} 
 
int yramdisk_EraseBlockInNAND(yaffs_Device *dev, int blockNumber) 
{ 
	 
	CheckInit(dev); 
	 
	if(blockNumber < 0 || blockNumber >= ramdisk.nBlocks) 
	{ 
		T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber)); 
		return YAFFS_FAIL; 
	} 
	else 
	{ 
		memset(ramdisk.block[blockNumber],0xFF,sizeof(yramdisk_Block)); 
		return YAFFS_OK; 
	} 
	 
} 
 
int yramdisk_InitialiseNAND(yaffs_Device *dev) 
{ 
	//dev->useNANDECC = 1; // force on useNANDECC which gets faked.  
						 // This saves us doing ECC checks. 
	 
	return YAFFS_OK; 
}