dvh.h

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/*
    Copyright (C) 1985 MIPS Computer Systems, Inc.
    Copyright (C) 2000 Silicon Graphics Computer Systems, 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 3 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, see <http://www.gnu.org/licenses/>.
*/
 
#ifndef _SYS_DVH_H
#define _SYS_DVH_H
 
/*
 * Format for volume header information
 *
 * The volume header is a block located at the beginning of all disk
 * media (sector 0).  It contains information pertaining to physical
 * device parameters and logical partition information.
 *
 * The volume header is manipulated by disk formatters/verifiers,
 * partition builders (e.g. fx, dvhtool, and mkfs), and disk drivers.
 *
 * Previous versions of IRIX wrote a copy of the volume header is
 * located at sector 0 of each track of cylinder 0.  These copies were
 * never used, and reduced the capacity of the volume header to hold large
 * files, so this practice was discontinued.
 * The volume header is constrained to be less than or equal to 512
 * bytes long.  A particular copy is assumed valid if no drive errors
 * are detected, the magic number is correct, and the 32 bit 2's complement
 * of the volume header is correct.  The checksum is calculated by initially
 * zeroing vh_csum, summing the entire structure and then storing the
 * 2's complement of the sum.  Thus a checksum to verify the volume header
 * should be 0.
 *
 * The error summary table, bad sector replacement table, and boot blocks are
 * located by searching the volume directory within the volume header.
 *
 * Tables are sized simply by the integral number of table records that
 * will fit in the space indicated by the directory entry.
 *
 * The amount of space allocated to the volume header, replacement blocks,
 * and other tables is user defined when the device is formatted.
 */
 
/*
 * device parameters are in the volume header to determine mapping
 * from logical block numbers to physical device addresses
 *
 * Linux doesn't care ...
 */
struct device_parameters {
        unsigned char   dp_skew;        /* spiral addressing skew */
        unsigned char   dp_gap1;        /* words of 0 before header */
        unsigned char   dp_gap2;        /* words of 0 between hdr and data */
        unsigned char   dp_spares_cyl;  /* This is for drives (such as SCSI
                that support zone oriented sparing, where the zone is larger
                than one track.  It gets subracteded from the cylinder size
                ( dp_trks0 * dp_sec) when doing partition size calculations */
        unsigned short  dp_cyls;        /* number of usable cylinders (i.e.,
                doesn't include cylinders reserved by the drive for badblocks,
                etc.). For drives with variable geometry, this number may be
                decreased so that:
                dp_cyls * ((dp_heads * dp_trks0) - dp_spares_cyl) <= actualcapacity
                This happens on SCSI drives such as the Wren IV and Toshiba 156
                Also see dp_cylshi below */
        unsigned short  dp_shd0;        /* starting head vol 0 */
        unsigned short  dp_trks0;       /* number of tracks / cylinder vol 0*/
        unsigned char   dp_ctq_depth;   /* Depth of CTQ queue */
        unsigned char   dp_cylshi;      /* high byte of 24 bits of cylinder count */
        unsigned short  dp_unused;      /* not used */
        unsigned short  dp_secs;        /* number of sectors/track */
        unsigned short  dp_secbytes;    /* length of sector in bytes */
        unsigned short  dp_interleave;  /* sector interleave */
        int     dp_flags;               /* controller characteristics */
        int     dp_datarate;            /* bytes/sec for kernel stats */
        int     dp_nretries;            /* max num retries on data error */
        int     dp_mspw;                /* ms per word to xfer, for iostat */
        unsigned short dp_xgap1;        /* Gap 1 for xylogics controllers */
        unsigned short dp_xsync;    /* sync delay for xylogics controllers */
        unsigned short dp_xrdly;    /* read delay for xylogics controllers */
        unsigned short dp_xgap2;    /* gap 2 for xylogics controllers */
        unsigned short dp_xrgate;   /* read gate for xylogics controllers */
        unsigned short dp_xwcont;   /* write continuation for xylogics */
};
 
/*
 * Device characterization flags
 * (dp_flags)
 */
#define DP_SECTSLIP     0x00000001      /* sector slip to spare sector */
#define DP_SECTFWD      0x00000002      /* forward to replacement sector */
#define DP_TRKFWD       0x00000004      /* forward to replacement track */
#define DP_MULTIVOL     0x00000008      /* multiple volumes per spindle */
#define DP_IGNOREERRORS 0x00000010      /* transfer data regardless of errors */
#define DP_RESEEK       0x00000020      /* recalibrate as last resort */
#define DP_CTQ_EN       0x00000040      /* enable command tag queueing */
 
/*
 * Boot blocks, bad sector tables, and the error summary table, are located
 * via the volume_directory.
 */
#define VDNAMESIZE      8
 
struct volume_directory {
        char    vd_name[VDNAMESIZE];    /* name */
        unsigned int    vd_lbn;                 /* logical block number */
        unsigned int    vd_nbytes;              /* file length in bytes */
};
 
/*
 * partition table describes logical device partitions
 * (device drivers examine this to determine mapping from logical units
 * to cylinder groups, device formatters/verifiers examine this to determine
 * location of replacement tracks/sectors, etc)
 *
 * NOTE: pt_firstlbn SHOULD BE CYLINDER ALIGNED
 */
struct partition_table {                /* one per logical partition */
        unsigned int    pt_nblks;               /* # of logical blks in partition */
        unsigned int    pt_firstlbn;            /* first lbn of partition */
        int             pt_type;                /* use of partition */
};
 
#define PTYPE_VOLHDR    0               /* partition is volume header */
#define PTYPE_TRKREPL   1               /* partition is used for repl trks */
#define PTYPE_SECREPL   2               /* partition is used for repl secs */
#define PTYPE_RAW       3               /* partition is used for data */
#define PTYPE_BSD42     4               /* partition is 4.2BSD file system */
#define PTYPE_BSD       4               /* partition is 4.2BSD file system */
#define PTYPE_SYSV      5               /* partition is SysV file system */
#define PTYPE_VOLUME    6               /* partition is entire volume */
#define PTYPE_EFS       7               /* partition is sgi EFS */
#define PTYPE_LVOL      8               /* partition is part of a logical vol */
#define PTYPE_RLVOL     9               /* part of a "raw" logical vol */
#define PTYPE_XFS       10              /* partition is sgi XFS */
#define PTYPE_XFSLOG    11              /* partition is sgi XFS log */
#define PTYPE_XLV       12              /* partition is part of an XLV vol */
#define PTYPE_XVM       13              /* partition is sgi XVM */
#define NPTYPES         16
 
#define VHMAGIC         0xbe5a941       /* randomly chosen value */
#define NPARTAB         16              /* 16 unix partitions */
#define NVDIR           15              /* max of 15 directory entries */
#define BFNAMESIZE      16              /* max 16 chars in boot file name */
 
/* Partition types for ARCS */
#define NOT_USED        0       /* Not used                             */
#define FAT_SHORT       1       /* FAT file system, 12-bit FAT entries  */
#define FAT_LONG        4       /* FAT file system, 16-bit FAT entries  */
#define EXTENDED        5       /* extended partition                   */
#define HUGE            6       /* huge partition- MS/DOS 4.0 and later */
 
/* Active flags for ARCS */
#define BOOTABLE        0x00;
#define NOT_BOOTABLE    0x80;
 
struct volume_header {
        int vh_magic;                           /* identifies volume header */
        short vh_rootpt;                        /* root partition number */
        short vh_swappt;                        /* swap partition number */
        char vh_bootfile[BFNAMESIZE];           /* name of file to boot */
        struct device_parameters vh_dp;         /* device parameters */
        struct volume_directory vh_vd[NVDIR];   /* other vol hdr contents */
        struct partition_table vh_pt[NPARTAB];  /* device partition layout */
        int vh_csum;                            /* volume header checksum */
        int vh_fill;    /* fill out to 512 bytes */
};
 
#endif /* _SYS_DVH_H */