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