clock.c revision 192109 
1/*-
2 * Copyright (C) 1995, 1996 Wolfgang Solfrank.
3 * Copyright (C) 1995, 1996 TooLs GmbH.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed by TooLs GmbH.
17 * 4. The name of TooLs GmbH may not be used to endorse or promote products
18 *    derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 *	$NetBSD: clock.c,v 1.9 2000/01/19 02:52:19 msaitoh Exp $
32 */
33/*
34 * Copyright (C) 2001 Benno Rice.
35 * All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 *    notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 *    notice, this list of conditions and the following disclaimer in the
44 *    documentation and/or other materials provided with the distribution.
45 *
46 * THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR
47 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
48 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
49 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
51 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
52 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
53 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
54 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
55 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56 */
57
58#include <sys/cdefs.h>
59__FBSDID("$FreeBSD: head/sys/powerpc/aim/clock.c 192109 2009-05-14 16:48:25Z raj $");
60
61#include <sys/param.h>
62#include <sys/systm.h>
63#include <sys/kernel.h>
64#include <sys/bus.h>
65#include <sys/interrupt.h>
66#include <sys/pcpu.h>
67#include <sys/sysctl.h>
68#include <sys/timetc.h>
69
70#include <dev/ofw/openfirm.h>
71
72#include <machine/clock.h>
73#include <machine/cpu.h>
74#include <machine/intr.h>
75#include <machine/md_var.h>
76#include <machine/smp.h>
77
78/*
79 * Initially we assume a processor with a bus frequency of 12.5 MHz.
80 */
81u_long			ns_per_tick = 80;
82static u_long		ticks_per_sec = 12500000;
83static long		ticks_per_intr;
84
85static timecounter_get_t	decr_get_timecount;
86
87static struct timecounter	decr_timecounter = {
88	decr_get_timecount,	/* get_timecount */
89	0,			/* no poll_pps */
90	~0u,			/* counter_mask */
91	0,			/* frequency */
92	"decrementer"		/* name */
93};
94
95void
96decr_intr(struct trapframe *frame)
97{
98	long		tick;
99	int		nticks;
100
101	/*
102	 * Check whether we are initialized.
103	 */
104	if (!ticks_per_intr)
105		return;
106
107	/*
108	 * Based on the actual time delay since the last decrementer reload,
109	 * we arrange for earlier interrupt next time.
110	 */
111	__asm ("mfdec %0" : "=r"(tick));
112	for (nticks = 0; tick < 0; nticks++)
113		tick += ticks_per_intr;
114	mtdec(tick);
115
116	if (PCPU_GET(cpuid) == 0) {
117		while (nticks-- > 0)
118			hardclock(TRAPF_USERMODE(frame), TRAPF_PC(frame));
119	} else {
120		while (nticks-- > 0)
121			hardclock_cpu(TRAPF_USERMODE(frame));
122	}
123}
124
125void
126decr_init(void)
127{
128	struct cpuref cpu;
129	register_t msr;
130
131	/*
132	 * Check the BSP's timebase frequency. Sometimes we can't find the BSP, so fall
133	 * back to the first CPU in this case.
134	 */
135
136	if (platform_smp_get_bsp(&cpu) != 0)
137		platform_smp_first_cpu(&cpu);
138
139	ticks_per_sec = platform_timebase_freq(&cpu);
140
141	msr = mfmsr();
142	mtmsr(msr & ~PSL_EE);
143
144	ns_per_tick = 1000000000 / ticks_per_sec;
145	ticks_per_intr = ticks_per_sec / hz;
146	mtdec(ticks_per_intr);
147
148	mtmsr(msr);
149}
150
151#ifdef SMP
152void
153decr_ap_init(void)
154{
155
156}
157#endif
158
159void
160decr_tc_init(void)
161{
162	decr_timecounter.tc_frequency = ticks_per_sec;
163	tc_init(&decr_timecounter);
164}
165
166static unsigned
167decr_get_timecount(struct timecounter *tc)
168{
169	register_t tb;
170
171	__asm __volatile("mftb %0" : "=r"(tb));
172	return (tb);
173}
174
175/*
176 * Wait for about n microseconds (at least!).
177 */
178void
179DELAY(int n)
180{
181	u_quad_t	tb, ttb;
182
183	tb = mftb();
184	ttb = tb + (n * 1000 + ns_per_tick - 1) / ns_per_tick;
185	while (tb < ttb)
186		tb = mftb();
187}
188
189/*
190 * Nothing to do.
191 */
192void
193cpu_startprofclock(void)
194{
195
196	/* Do nothing */
197}
198
199void
200cpu_stopprofclock(void)
201{
202}
203