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/* $NetBSD: alpha_mmclock_init.c,v 1.1 1995/12/20 12:55:21 cgd Exp $ */
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Chris G. Demetriou
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/types.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
#include <machine/sysarch.h>
#include "libalpha.h"
volatile struct alpha_timedata *alpha_mmclockdata;
u_long alpha_cycles_per_second;
int __alpha_mmclock_init_failed;
volatile struct alpha_timedata *
alpha_mmclock_init()
{
int fd;
if (alpha_mmclockdata != NULL)
return (alpha_mmclockdata);
fd = open("/dev/mmclock", O_RDONLY, 0);
if (fd == -1)
goto fail;
alpha_mmclockdata = (struct alpha_timedata *)
mmap(NULL, getpagesize(), PROT_READ, MAP_FILE, fd, 0);
close(fd);
if (alpha_mmclockdata == NULL)
goto fail;
alpha_cycles_per_second = alpha_mmclockdata->td_cpc;
__alpha_mmclock_init_failed = 0;
return (alpha_mmclockdata);
fail:
__alpha_mmclock_init_failed = 1;
return (NULL);
}
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