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ccdvar.h revision 1.2 
      1 /*	$NetBSD: ccdvar.h,v 1.2 1994/06/29 06:31:31 cgd Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1988 University of Utah.
      5  * Copyright (c) 1990 The Regents of the University of California.
      6  * All rights reserved.
      7  *
      8  * This code is derived from software contributed to Berkeley by
      9  * the Systems Programming Group of the University of Utah Computer
     10  * Science Department.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  *
     40  * from: Utah $Hdr: cdvar.h 1.1 90/07/09$
     41  *
     42  *	@(#)cdvar.h	7.2 (Berkeley) 11/4/90
     43  */
     44 
     45 #define	NCCDISKS	8		/* max # of component disks */
     46 
     47 /*
     48  * A concatenated disk is described at config time by this structure.
     49  */
     50 struct ccddevice {
     51 	int	ccd_unit;		/* logical unit of this ccd */
     52 	int	ccd_interleave;		/* interleave (DEV_BSIZE blocks) */
     53 	int	ccd_flags;		/* misc. information */
     54 	int	ccd_dk;			/* disk number */
     55 	dev_t	ccd_dev[NCCDISKS];	/* component devices */
     56 };
     57 
     58 /* ccd_flags */
     59 #define	CDF_SWAP	0x01	/* interleave should be dmmax */
     60 #define CDF_UNIFORM	0x02	/* use LCD of sizes for uniform interleave */
     61 
     62 /*
     63  * Component info table.
     64  * Describes a single component of a concatenated disk.
     65  */
     66 struct ccdcinfo {
     67 	dev_t		ci_dev;	 /* devno */
     68 	size_t		ci_size; /* size */
     69 };
     70 
     71 /*
     72  * Interleave description table.
     73  * Computed at boot time to speed irregular-interleave lookups.
     74  * The idea is that we interleave in "groups".  First we interleave
     75  * evenly over all component disks up to the size of the smallest
     76  * component (the first group), then we interleave evenly over all
     77  * remaining disks up to the size of the next-smallest (second group),
     78  * and so on.
     79  *
     80  * Each table entry describes the interleave characteristics of one
     81  * of these groups.  For example if a concatenated disk consisted of
     82  * three components of 5, 3, and 7 DEV_BSIZE blocks interleaved at
     83  * DEV_BSIZE (1), the table would have three entries:
     84  *
     85  *	ndisk	startblk	startoff	dev
     86  *	3	0		0		0, 1, 2
     87  *	2	9		3		0, 2
     88  *	1	13		5		2
     89  *	0	-		-		-
     90  *
     91  * which says that the first nine blocks (0-8) are interleaved over
     92  * 3 disks (0, 1, 2) starting at block offset 0 on any component disk,
     93  * the next 4 blocks (9-12) are interleaved over 2 disks (0, 2) starting
     94  * at component block 3, and the remaining blocks (13-14) are on disk
     95  * 2 starting at offset 5.
     96  */
     97 struct ccdiinfo {
     98 	int	ii_ndisk;	/* # of disks range is interleaved over */
     99 	daddr_t	ii_startblk;	/* starting scaled block # for range */
    100 	daddr_t	ii_startoff;	/* starting component offset (block #) */
    101 	char	ii_index[NCCDISKS];/* ordered list of components in range */
    102 };
    103 
    104 #ifdef KERNEL
    105 extern	struct ccddevice ccddevice[];
    106 #endif
    107