1 /* $NetBSD: clock.c,v 1.27 2012/10/27 17:18:04 chs Exp $ */
2
3 /*
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * All advertising materials mentioning features or use of this software
12 * must display the following acknowledgement:
13 * This product includes software developed by the University of
14 * California, Lawrence Berkeley Laboratory.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
24 * 3. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * @(#)clock.c 8.1 (Berkeley) 6/11/93
41 */
42
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.27 2012/10/27 17:18:04 chs Exp $");
45
46 #include <sys/param.h>
47 #include <sys/kernel.h>
48 #include <sys/systm.h>
49 #include <sys/device.h>
50
51 #include <machine/psl.h>
52 #include <machine/bus.h>
53
54 #include <dev/mvme/clockvar.h>
55
56 static struct clock_attach_args *clock_args;
57
58 struct evcnt clock_profcnt;
59 struct evcnt clock_statcnt;
60
61 /*
62 * Statistics clock interval and variance, in usec. Variance must be a
63 * power of two. Since this gives us an even number, not an odd number,
64 * we discard one case and compensate. That is, a variance of 1024 would
65 * give us offsets in [0..1023]. Instead, we take offsets in [1..1023].
66 * This is symmetric about the point 512, or statvar/2, and thus averages
67 * to that value (assuming uniform random numbers).
68 */
69 /* XXX fix comment to match value */
70 int clock_statvar = 8192;
71 int clock_statmin; /* statclock interval - (1/2 * variance) */
72
73
74 /*
75 * Common parts of clock autoconfiguration.
76 */
77 void
clock_config(device_t dev,struct clock_attach_args * ca,struct evcnt * ev)78 clock_config(device_t dev, struct clock_attach_args *ca, struct evcnt *ev)
79 {
80 extern int delay_divisor; /* from machdep.c */
81
82 /* Hook up that which we need. */
83 clock_args = ca;
84
85 evcnt_attach_dynamic(&clock_profcnt, EVCNT_TYPE_INTR, ev,
86 device_xname(dev), "profint");
87 evcnt_attach_dynamic(&clock_statcnt, EVCNT_TYPE_INTR, ev,
88 device_xname(dev), "statint");
89
90 /* Print info about the clock. */
91 printf(": delay_divisor %d\n", delay_divisor);
92 }
93
94 /*
95 * Set up the real-time and statistics clocks. Leave stathz 0 only
96 * if no alternative timer is available.
97 *
98 * The frequencies of these clocks must be an even number of microseconds.
99 */
100 void
cpu_initclocks(void)101 cpu_initclocks(void)
102 {
103 int statint, minint;
104
105 if (clock_args == NULL)
106 panic("clock not configured");
107
108 if (1000000 % hz) {
109 printf("cannot get %d Hz clock; using 100 Hz\n", hz);
110 hz = 100;
111 tick = 1000000 / hz;
112 }
113 if (stathz == 0)
114 stathz = hz;
115 if (1000000 % stathz) {
116 printf("cannot get %d Hz statclock; using 100 Hz\n", stathz);
117 stathz = 100;
118 }
119 profhz = stathz; /* always */
120
121 statint = 1000000 / stathz;
122 minint = statint / 2 + 100;
123 while (clock_statvar > minint)
124 clock_statvar >>= 1;
125
126 clock_statmin = statint - (clock_statvar >> 1);
127
128 /* Call the machine-specific initclocks hook. */
129 (*clock_args->ca_initfunc)(clock_args->ca_arg, tick, statint);
130 }
131
132 void
setstatclockrate(int newhz)133 setstatclockrate(int newhz)
134 {
135
136 /* XXX should we do something here? XXX */
137 }
138