/*

 *  GRUB  --  GRand Unified Bootloader

 *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

/*

 * Use is subject to license terms.

 */

#ifndef	_SYS_ZAP_IMPL_H

#define	_SYS_ZAP_IMPL_H

#define	ZAP_MAGIC 0x2F52AB2ABULL

#define	MZAP_ENT_LEN		64

#define	MZAP_NAME_LEN		(MZAP_ENT_LEN - 8 - 4 - 2)

#define	MZAP_MAX_BLKSHIFT	SPA_MAXBLOCKSHIFT

#define	MZAP_MAX_BLKSZ		(1 << MZAP_MAX_BLKSHIFT)

typedef struct mzap_ent_phys {

	uint64_t mze_value;

	uint32_t mze_cd;

	uint16_t mze_pad;	/* in case we want to chain them someday */

	char mze_name[MZAP_NAME_LEN];

} mzap_ent_phys_t;

typedef struct mzap_phys {

	uint64_t mz_block_type;	/* ZBT_MICRO */

	uint64_t mz_salt;

	uint64_t mz_pad[6];

	mzap_ent_phys_t mz_chunk[1];

	/* actually variable size depending on block size */

} mzap_phys_t;

/*

 * The (fat) zap is stored in one object. It is an array of

 * 1<<FZAP_BLOCK_SHIFT byte blocks. The layout looks like one of:

 *

 * ptrtbl fits in first block:

 * 	[zap_phys_t zap_ptrtbl_shift < 6] [zap_leaf_t] ...

 *

 * ptrtbl too big for first block:

 * 	[zap_phys_t zap_ptrtbl_shift >= 6] [zap_leaf_t] [ptrtbl] ...

 *

 */

#define	ZBT_LEAF		((1ULL << 63) + 0)

#define	ZBT_HEADER		((1ULL << 63) + 1)

#define	ZBT_MICRO		((1ULL << 63) + 3)

/* any other values are ptrtbl blocks */

/*

 * the embedded pointer table takes up half a block:

 * block size / entry size (2^3) / 2

 */

#define	ZAP_EMBEDDED_PTRTBL_SHIFT(zap) (FZAP_BLOCK_SHIFT(zap) - 3 - 1)

/*

 * The embedded pointer table starts half-way through the block.  Since

 * the pointer table itself is half the block, it starts at (64-bit)

 * word number (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap)).

 */

#define	ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) \

	((uint64_t *)(zap)->zap_f.zap_phys) \

	[(idx) + (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap))]

/*

 * TAKE NOTE:

 * If zap_phys_t is modified, zap_byteswap() must be modified.

 */

typedef struct zap_phys {

	uint64_t zap_block_type;	/* ZBT_HEADER */

	uint64_t zap_magic;		/* ZAP_MAGIC */

	struct zap_table_phys {

		uint64_t zt_blk;	/* starting block number */

		uint64_t zt_numblks;	/* number of blocks */

		uint64_t zt_shift;	/* bits to index it */

		uint64_t zt_nextblk;	/* next (larger) copy start block */

		uint64_t zt_blks_copied; /* number source blocks copied */

	} zap_ptrtbl;

	uint64_t zap_freeblk;		/* the next free block */

	uint64_t zap_num_leafs;		/* number of leafs */

	uint64_t zap_num_entries;	/* number of entries */

	uint64_t zap_salt;		/* salt to stir into hash function */

	/*

	 * This structure is followed by padding, and then the embedded

	 * pointer table.  The embedded pointer table takes up second

	 * half of the block.  It is accessed using the

	 * ZAP_EMBEDDED_PTRTBL_ENT() macro.

	 */

} zap_phys_t;

#endif /* _SYS_ZAP_IMPL_H */