siacs.c 2.54 KB

/*====================================================================
 * siacs.c
 *
 * Copyright 1995, Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This is UNPUBLISHED PROPRIETARY SOURCE CODE of Silicon Graphics,
 * Inc.; the contents of this file may not be disclosed to third
 * parties, copied or duplicated in any form, in whole or in part,
 * without the prior written permission of Silicon Graphics, Inc.
 *
 * RESTRICTED RIGHTS LEGEND:
 * Use, duplication or disclosure by the Government is subject to
 * restrictions as set forth in subdivision (c)(1)(ii) of the Rights
 * in Technical Data and Computer Software clause at DFARS
 * 252.227-7013, and/or in similar or successor clauses in the FAR,
 * DOD or NASA FAR Supplement. Unpublished - rights reserved under the
 * Copyright Laws of the United States.
 *====================================================================*/

/**************************************************************************
 *
 *  $Revision: 1.1.1.2 $
 *  $Date: 2002/10/29 08:06:43 $
 *  $Source: /root/leakn64/depot/rf/sw/bbplayer/libultra/monegi/si/siacs.c,v $
 *
 *  Description:
 *	This file contains routines to get access to the SI device.
 *
 **************************************************************************/


#include "osint.h"
#include "siint.h"


#define NUM_ACCESS_MESG		1

/* Access queue used for mutual exclusion on SI */
static OSMesg	siAccessBuf[NUM_ACCESS_MESG];

OSMesgQueue	__osSiAccessQueue;
int		__osSiAccessQueueEnabled = 0;


/*
 * Name:   __osSiCreateAccessQueue
 *
 * Description:
 *	
 *
 * Globals Referenced: 
 *	None
 */
void
__osSiCreateAccessQueue(void)
{
    __osSiAccessQueueEnabled = 1;

    osCreateMesgQueue(&__osSiAccessQueue, siAccessBuf, NUM_ACCESS_MESG);

    /* Initialize the access queue with a resource token */
    (void)osSendMesg(&__osSiAccessQueue, (OSMesg)0, OS_MESG_NOBLOCK);
}


/*
 * Name:   __osSiGetAccess
 *
 * Description:
 *	Get the access right to SI by blocking on the access queue. 
 *
 * Globals Referenced: 
 *	__osSiAccessQueue
 */
void
__osSiGetAccess(void)
{
    OSMesg dummyMesg;

    /* Create access message queue if haven't done so */
    if (!__osSiAccessQueueEnabled) {
        __osSiCreateAccessQueue();
    }

    (void)osRecvMesg(&__osSiAccessQueue, &dummyMesg, OS_MESG_BLOCK);
}


/*
 * Name:   __osSiRelAccess
 *
 * Description:
 *	Release the access right to SI by sending a mesg to the access queue. 
 *
 * Globals Referenced: 
 *	__osSiAccessQueue
 */
void
__osSiRelAccess(void)
{
    (void)osSendMesg(&__osSiAccessQueue, (OSMesg)0, OS_MESG_NOBLOCK);
}