Header File

/**************************************************************************
 *                                                                      *
 *                Copyright (C) 1993, Silicon Graphics, Inc.             *
 *                                                                      *
 *  These coded instructions, statements, and computer programs  contain  *
 *  unpublished  proprietary  information of Silicon Graphics, Inc., and  *
 *  are protected by Federal copyright law.  They  may  not be disclosed  *
 *  to  third  parties  or copied or duplicated in any form, in whole or  *
 *  in part, without the prior written consent of Silicon Graphics, Inc.  *
 *                                                                       *
 **************************************************************************/

/**************************************************************************
| This is ramdrive.h, containing declarations that are used in both the
| driver and in the unit-test application code.  Aside from the unit-test
| module, no user-level code ever needs these declarations.  The ram drive
| is accessed through the file system like any other disk.
***************************************************************************/

/**************************************************************************
| The driver name for lboot and configuration is "ramdrive."
| The driver prefix is "rd_"
***************************************************************************/

#define DRIVER_PFX "rd_"
#define DRIVER_NAME "ramdrive"

/**************************************************************************
| MAX_RD_DEVS declares the maximum number of distinct devices supported.
| Ram drive device special files are /dev/dsk/ramblk<n> for block devices
| and /dev/rdsk/ramchr<n> for character devices.  In each case <n> is the
| device minor number, between 0 and MAX_RD_DEVS-1.
**************************************************************************/

#define MAX_RD_DEVS 4

/**************************************************************************
| An array of MAX_RD_DEVS structures of the following type is maintained
| in the driver. VECTOR lines for up to MAX_RD_DEVS devices are written
| in /var/sysgen/system/ramdrive.sm, causing that many entries to the
| rd_edtinit() entry point, each entry initializing one structure.
|
| base:    address of allocated memory for the "drive."  If NULL, this
|          minor number has not been initialized or failed initialization.
|
| size:    size of the allocated memory in bytes, always rounded down to
|          a multiple of IO_NBPP.
|
| copen:   count of successful character opens, cleared to 0 in rd_close().
| bopen:   count of successful block opens (0 or 1), cleared in rd_close().
| xopen:   nonzero when an FEXCL open has succeeded.
|
| nmmap:   count of rd_map() entries, decremented in rd_unmap().  When the
|          any of copen, bopen, and nmaps over all devices is nonzero, the
|          driver returns EBUSY to the rd_unload() entry point.
|
| queue:   semaphore used to serialize access for reading and writing.
|          (Note however that in a multiprocessor, a user process can
|          perform an unsynchronized write to a mapped character device.)
|
| vh:      volume header structure prepared in edtinit(), and used to
|          initialize block 0 when "formatting" the drive.  The block-0
|          version can be modified by /etc/mkfs.
**************************************************************************/

typedef struct rd_info {
    caddr_t     *base;
    off_t       size;
    __uint32_t  copen, bopen, xopen, nmmap;
    sema_t      queue;  /* requires sys/sema.h */
    struct volume_header vh; /* requires sys/dvh.h */
} rd_info_t;