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      1 /*	$NetBSD: clockvar.h,v 1.1 2024/01/02 07:41:00 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1996, 2002, 2023 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _VIRT68K_CLOCKVAR_H_
     33 #define _VIRT68K_CLOCKVAR_H_
     34 
     35 #include <sys/evcnt.h>
     36 #include <dev/clock_subr.h>
     37 
     38 extern	int clock_statvar;
     39 extern	int clock_statmin;
     40 struct clockframe;
     41 
     42 #define	CLOCK_NONE		-1
     43 #define	CLOCK_HARDCLOCK		0
     44 #define	CLOCK_STATCLOCK		1
     45 #define	NCLOCKS			2
     46 
     47 struct clock_attach_args {
     48 	void			(*ca_initfunc)(void *, unsigned int,
     49 				    struct evcnt *ev,
     50 				    void (*func)(struct clockframe *));
     51 	void			*ca_arg;
     52 	struct evcnt		*ca_parent_evcnt;
     53 	int			ca_which;
     54 };
     55 
     56 const char *clock_name(int);
     57 void	clock_attach(device_t, struct clock_attach_args *,
     58 	    void (*)(device_t, unsigned int));
     59 
     60 extern void *clock_devices[NCLOCKS];
     61 
     62 /*
     63  * Macro to compute a new randomized interval.  The intervals are
     64  * uniformly distributed on [statint - statvar / 2, statint + statvar / 2],
     65  * and therefore have mean statint, giving a stathz frequency clock.
     66  *
     67  * This is gratuitously stolen from sparc/sparc/clock.c
     68  */
     69 #define CLOCK_NEWINT(statvar, statmin)	({				\
     70 		u_long r, var = (statvar);				\
     71 		do { r = random() & (var - 1); } while (r == 0);	\
     72 		(statmin + r);						\
     73 	})
     74 
     75 /*
     76  * Sun chose the year `68' as their base count, so that
     77  * cl_year==0 means 1968.
     78  */
     79 #define YEAR0   1968
     80 
     81 #endif /* _VIRT68K_CLOCKVAR_H_ */
     82