1 /* $NetBSD: clock.c,v 1.47 2022/04/05 04:33:36 skrll Exp $ */
2
3 /*
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1992, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department and Ralph Campbell.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: Utah Hdr: clock.c 1.18 91/01/21
37 *
38 * @(#)clock.c 8.1 (Berkeley) 6/10/93
39 */
40
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.47 2022/04/05 04:33:36 skrll Exp $");
43
44 #include <sys/param.h>
45 #include <sys/kernel.h>
46 #include <sys/systm.h>
47 #include <sys/device.h>
48 #include <sys/lwp.h>
49
50 #include <machine/alpha.h>
51 #include <machine/autoconf.h>
52 #include <machine/cpuconf.h>
53 #include <machine/cpu_counter.h>
54
55 #include <alpha/alpha/clockvar.h>
56
57 #define PCC_QUAL 1000
58
59 void (*clock_init)(void *);
60 void *clockdev;
61
62 int alpha_use_cctr; /* != 0 if we're using the PCC timecounter */
63
64 void
clockattach(void (* fns)(void *),void * dev)65 clockattach(void (*fns)(void *), void *dev)
66 {
67
68 /*
69 * Just bookkeeping. We only allow one system clock. If
70 * we're running on real hardware, enforce this. If we're
71 * running under Qemu, anything after the first one.
72 */
73 if (clock_init != NULL) {
74 if (alpha_is_qemu) {
75 return;
76 }
77 panic("clockattach: multiple clocks");
78 }
79 clock_init = fns;
80 clockdev = dev;
81 }
82
83 /*
84 * Start the real-time and statistics clocks. Leave stathz 0 since there
85 * are no other timers available.
86 */
87 void
cpu_initclocks(void)88 cpu_initclocks(void)
89 {
90
91 if (clock_init == NULL)
92 panic("cpu_initclocks: no clock attached");
93
94 /*
95 * Establish the clock interrupt; it's a special case.
96 *
97 * We establish the clock interrupt this late because if
98 * we do it at clock attach time, we may have never been at
99 * spl0() since taking over the system. Some versions of
100 * PALcode save a clock interrupt, which would get delivered
101 * when we spl0() in autoconf.c. If established the clock
102 * interrupt handler earlier, that interrupt would go to
103 * hardclock, which would then fall over because p->p_stats
104 * isn't set at that time.
105 */
106 platform.clockintr = hardclock;
107 schedhz = 16;
108
109 /*
110 * Initialize PCC timecounter, unless we're running in Qemu
111 * (we will use a different timecounter in that case).
112 */
113 if (!alpha_is_qemu) {
114 const uint64_t pcc_freq = cpu_frequency(curcpu());
115 cc_init(NULL, pcc_freq, "PCC", PCC_QUAL);
116 alpha_use_cctr = 1;
117 }
118
119 /*
120 * Get the clock started.
121 */
122 (*clock_init)(clockdev);
123 }
124
125 /*
126 * Some platforms might have other per-cpu clock initialization. This
127 * is handled here.
128 */
129 void
cpu_initclocks_secondary(void)130 cpu_initclocks_secondary(void)
131 {
132 (*clock_init)(clockdev);
133 }
134
135 /*
136 * We assume newhz is either stathz or profhz, and that neither will
137 * change after being set up above. Could recalculate intervals here
138 * but that would be a drag.
139 */
140 void
setstatclockrate(int newhz)141 setstatclockrate(int newhz)
142 {
143
144 /* nothing we can do */
145 }
146