yaffs_guts.h

一个 yaffs2 日志文件系统 支持NAND FLASH等

/*
 * YAFFS: Yet another FFS. A NAND-flash specific file system. 
 * yaffs_guts.h: Configuration etc for yaffs_guts
 *
 * Copyright (C) 2002 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 Lesser General Public License version 2.1 as
 * published by the Free Software Foundation.
 *
 *
 * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
 *
 * $Id: yaffs_guts.h,v 1.16 2003/01/31 03:30:33 charles Exp $
 */

#ifndef __YAFFS_GUTS_H__
#define __YAFFS_GUTS_H__

#include "devextras.h"


#define YAFFS_OK	1
#define YAFFS_FAIL  0

// Give us a Y=0x59, 
// Give us an A=0x41, 
// Give us an FF=0xFF 
// Give us an S=0x53
// And what have we got... 
#define YAFFS_MAGIC					0x5941FF53

#define YAFFS_NTNODES_LEVEL0	  	16
#define YAFFS_TNODES_LEVEL0_BITS	4
#define YAFFS_TNODES_LEVEL0_MASK	0xf

#define YAFFS_NTNODES_INTERNAL 		(YAFFS_NTNODES_LEVEL0 / 2)
#define YAFFS_TNODES_INTERNAL_BITS 	(YAFFS_TNODES_LEVEL0_BITS - 1)
#define YAFFS_TNODES_INTERNAL_MASK	0x7
#define YAFFS_TNODES_MAX_LEVEL		6
		
#define YAFFS_BYTES_PER_SPARE		16

#define YAFFS_BYTES_PER_CHUNK		512
//#define YAFFS_CHUNK_SIZE_SHIFT		9


#define YAFFS_CHUNKS_PER_BLOCK		32
#define YAFFS_BYTES_PER_BLOCK		(YAFFS_CHUNKS_PER_BLOCK*YAFFS_BYTES_PER_CHUNK)

#define YAFFS_MAX_CHUNK_ID			0x000FFFFF

#define YAFFS_UNUSED_OBJECT_ID		0x0003FFFF

#define YAFFS_ALLOCATION_NOBJECTS	100
#define YAFFS_ALLOCATION_NTNODES	100
#define YAFFS_ALLOCATION_NLINKS		100

#define YAFFS_NOBJECT_BUCKETS		256


#define YAFFS_OBJECT_SPACE			0x40000
#define YAFFS_MAX_NAME_LENGTH		255
#define YAFFS_SHORT_NAME_LENGTH		15

#define YAFFS_MAX_ALIAS_LENGTH		159

#define YAFFS_OBJECTID_ROOT			1
#define YAFFS_OBJECTID_LOSTNFOUND	2
#define YAFFS_OBJECTID_UNLINKED		3

#define YAFFS_MAX_SHORT_OP_CACHES	20


// ChunkCache is used for short read/write operations.
typedef struct
{
	struct yaffs_ObjectStruct *object;
	int chunkId;
	int lastUse;
	int dirty;	
	int nBytes;	// Only valid if the cache is dirty
	__u8 data[YAFFS_BYTES_PER_CHUNK];
} yaffs_ChunkCache;

// Tags structures in RAM
// NB This uses bitfield. Bitfields should not straddle a u32 boundary otherwise
// the structure size will get blown out.

typedef struct
{
    unsigned chunkId:20;
    unsigned serialNumber:2;
    unsigned byteCount:10;
    unsigned objectId:18;
    unsigned ecc:12;
    unsigned unusedStuff:2;
} yaffs_Tags;

typedef union
{
    yaffs_Tags asTags;
    __u8       asBytes[8];
} yaffs_TagsUnion;


// Spare structure
typedef struct
{
    __u8  tagByte0;
    __u8  tagByte1;
    __u8  tagByte2;
    __u8  tagByte3;
    __u8  pageStatus; 	// set to 0 to delete the chunk
    __u8  blockStatus;
    __u8  tagByte4;
    __u8  tagByte5;
    __u8  ecc1[3];
    __u8  tagByte6;
    __u8  tagByte7;
    __u8  ecc2[3];
} yaffs_Spare;

//Special structure for passing through to mtd
struct yaffs_NANDSpare {
	yaffs_Spare	spare;
	int		eccres1;
	int		eccres2;
};

// Block data in RAM

typedef enum {
	YAFFS_BLOCK_STATE_UNKNOWN	= 0,
	YAFFS_BLOCK_STATE_SCANNING,		// Used while the block is being scanned.
									// NB Don't erase blocks while they're being scanned
	
	YAFFS_BLOCK_STATE_EMPTY,		// This block is empty
	
	YAFFS_BLOCK_STATE_ALLOCATING,	// This block is partially allocated. 
									// This is the one currently being used for page
									// allocation. Should never be more than one of these
							

	YAFFS_BLOCK_STATE_FULL,			// All the pages in this block have been allocated.
									// At least one page holds valid data.
							 
	YAFFS_BLOCK_STATE_DIRTY,		// All pages have been allocated and deleted. 
									// Erase me, reuse me.
							
	YAFFS_BLOCK_STATE_DEAD 			// This block has failed and is not in use

} yaffs_BlockState;




typedef struct
{
#ifndef CONFIG_YAFFS_NO_YAFFS2
	__u32 sequenceNumber;	// block sequence number for yaffs2
#endif
	int   softDeletions:8;  // number of soft deleted pages
    int   pagesInUse:8;		// number of pages in use
    __u32 blockState:4; 	// One of the above block states
    __u32 needsRetiring:1;	// Data has failed on this block, need to get valid data off
    						// and retire the block.
} yaffs_BlockInfo;


//////////////////// Object structure ///////////////////////////
// This is the object structure as stored on NAND

typedef enum
{
	YAFFS_OBJECT_TYPE_UNKNOWN,
	YAFFS_OBJECT_TYPE_FILE,
	YAFFS_OBJECT_TYPE_SYMLINK,
	YAFFS_OBJECT_TYPE_DIRECTORY,
	YAFFS_OBJECT_TYPE_HARDLINK,
	YAFFS_OBJECT_TYPE_SPECIAL
} yaffs_ObjectType;

typedef struct
{
	yaffs_ObjectType type;

	// Apply to everything	
	int   parentObjectId;
	__u16 sum__NoLongerUsed;	// checksum of name. Calc this off the name to prevent inconsistencies
	char  name[YAFFS_MAX_NAME_LENGTH + 1];

	// Thes following apply to directories, files, symlinks - not hard links
	__u32 st_mode;  // protection

#ifdef CONFIG_YAFFS_WINCE
	__u32 notForWinCE[5];
#else
	__u32 st_uid;   // user ID of owner
	__u32 st_gid;    // group ID of owner 
	__u32 st_atime; // time of last access
	__u32 st_mtime; // time of last modification
	__u32 st_ctime; // time of last change
#endif

	// File size  applies to files only
	int fileSize; 
		
	// Equivalent object id applies to hard links only.
	int  equivalentObjectId;
	
	// Alias is for symlinks only.
	char alias[YAFFS_MAX_ALIAS_LENGTH + 1];
	
	__u32 st_rdev;  // device stuff for block and char devices (maj/min)
	
#ifdef CONFIG_YAFFS_WINCE
	__u32 win_ctime[2];
	__u32 win_atime[2];
	__u32 win_mtime[2];
	__u32 roomToGrow[6];
#else
	__u32 roomToGrow[12];
#endif
	
} yaffs_ObjectHeader;



////////////////////  Tnode ///////////////////////////

union yaffs_Tnode_union
{
#ifdef CONFIG_YAFFS_TNODE_LIST_DEBUG
	union yaffs_Tnode_union *internal[YAFFS_NTNODES_INTERNAL+1];
#else
	union yaffs_Tnode_union *internal[YAFFS_NTNODES_INTERNAL];
#endif
	__u16 level0[YAFFS_NTNODES_LEVEL0];
	
};

typedef union yaffs_Tnode_union yaffs_Tnode;

struct yaffs_TnodeList_struct
{
	struct yaffs_TnodeList_struct *next;
	yaffs_Tnode *tnodes;
};

typedef struct yaffs_TnodeList_struct yaffs_TnodeList;



///////////////////  Object ////////////////////////////////
// An object can be one of:
// - a directory (no data, has children links
// - a regular file (data.... not prunes :->).
// - a symlink [symbolic link] (the alias).
// - a hard link


typedef struct 
{
	__u32 fileSize;
	__u32 scannedFileSize;
	int   topLevel;
	yaffs_Tnode *top;
} yaffs_FileStructure;

typedef struct
{
	struct list_head children; // list of child links
} yaffs_DirectoryStructure;

typedef struct
{
	char *alias;
} yaffs_SymLinkStructure;

typedef struct
{
	struct yaffs_ObjectStruct *equivalentObject;
	__u32	equivalentObjectId;
} yaffs_HardLinkStructure;

typedef union
{
	yaffs_FileStructure fileVariant;
	yaffs_DirectoryStructure directoryVariant;
	yaffs_SymLinkStructure symLinkVariant;
	yaffs_HardLinkStructure hardLinkVariant;