yaffs_guts.h

YAFFS的升级版本YAFFS2

/*
 * 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 1.1 2004/11/03 08:14:07 charles Exp $
 */

#ifndef __YAFFS_GUTS_H__
#define __YAFFS_GUTS_H__

#include "devextras.h"
#include "yportenv.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

#ifndef CONFIG_YAFFS_NO_YAFFS1
#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)
#endif

#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

#ifdef CONFIG_YAFFS_UNICODE
#define YAFFS_MAX_NAME_LENGTH		127
#define YAFFS_MAX_ALIAS_LENGTH		79
#else
#define YAFFS_MAX_NAME_LENGTH		255
#define YAFFS_MAX_ALIAS_LENGTH		159
#endif

#define YAFFS_SHORT_NAME_LENGTH		15


#define YAFFS_OBJECTID_ROOT			1
#define YAFFS_OBJECTID_LOSTNFOUND	2
#define YAFFS_OBJECTID_UNLINKED		3
#define YAFFS_OBJECTID_DELETED		4

#define YAFFS_MAX_SHORT_OP_CACHES	20

#define YAFFS_N_TEMP_BUFFERS		4

// Sequence numbers are used in YAFFS2 to determine block allocation order.
// The range is limited slightly to help distinguish bad numbers from good.
// This also allows us to perhaps in the future use special numbers for
// special purposes.
// EFFFFF00 allows the allocation of 8 blocks per second (~1Mbytes) for 15 years, 
// and is a larger number than the lifetime of a 2GB device.

#define YAFFS_LOWEST_SEQUENCE_NUMBER	0x00001000
#define YAFFS_HIGHEST_SEQUENCE_NUMBER	0xEFFFFF00


// 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
	int locked; // Can't push out or flush while locked..
#ifdef YAFFS2_DEFINES
	__u8 *data;
#else
	__u8 data[YAFFS_BYTES_PER_CHUNK];
#endif
} yaffs_ChunkCache;


#ifndef CONFIG_YAFFS_NO_YAFFS1
// 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;

#endif

typedef enum
{
	YAFFS_ECC_RESULT_UNKNOWN,
	YAFFS_ECC_RESULT_NO_ERROR,
	YAFFS_ECC_RESULT_FIXED,
	YAFFS_ECC_RESULT_UNFIXED
} yaffs_ECCResult;

typedef struct
{

	unsigned validMarker0;
	unsigned chunkUsed;		    //  Status of the chunk: used or unused
	unsigned objectId;			// If 0 then this is not part of an object (unused)
	unsigned chunkId;			// If 0 then this is a header
	unsigned byteCount;		    // Only valid for data chunks
	// The following stuff only has meaning when we read
	yaffs_ECCResult eccResult;  // Only valid when we read.
	unsigned blockBad;			// Only valid on reading

	// YAFFS 1 stuff	
	unsigned chunkDeleted;		// The chunk is marked deleted
	unsigned serialNumber; 		// Yaffs1 2-bit serial number
	
	// YAFFS2 stuff
	unsigned sequenceNumber; 	// The sequence number of this block

	unsigned validMarker1;
	
} yaffs_ExtendedTags;

#ifndef CONFIG_YAFFS_NO_YAFFS1
// 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;
};
#endif


// Block data in RAM

typedef enum {
	YAFFS_BLOCK_STATE_UNKNOWN	= 0,
#ifndef YAFFS2_DEFINES
	YAFFS_BLOCK_STATE_SCANNING,
#else
	YAFFS_BLOCK_STATE_NEEDS_SCANNING,// The block might have something on it (ie it is allocating or full, perhaps empty)
									// but it needs to be scanned to determine its true state.
									// This state is only valid during yaffs_Scan.
									// NB We tolerate empty because the pre-scanner might be incapable of deciding
									// However, if this state is returned on a YAFFS2 device, then we expect a sequence number
									
#endif	
	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_COLLECTING,	// This block is being garbage collected
							
	YAFFS_BLOCK_STATE_DEAD 			// This block has failed and is not in use

} yaffs_BlockState;




typedef struct
{

	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.
#ifndef CONFIG_YAFFS_NO_YAFFS2
	__u32 hasShrinkHeader:1;// This block has at least one object header that does a shrink
	__u32 sequenceNumber;	// block sequence number for yaffs2
#endif

} 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
	YCHAR  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.
	YCHAR 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[5];
#else
	__u32 roomToGrow[11];
#endif

	// isShrink applies to bject headers written when we shrink the file (ie resize)
	__u32 isShrink;
	
} 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
{
	YCHAR *alias;
} yaffs_SymLinkStructure;