aboutsummaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/time.c
blob: 2995be1ab3cada3d9771e46cb95727f601cbad53 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
/*
 * Copyright 2001 MontaVista Software Inc.
 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
 * Copyright (c) 2003, 2004  Maciej W. Rozycki
 *
 * Common time service routines for MIPS machines.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */
#include <linux/bug.h>
#include <linux/clockchips.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/param.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/module.h>

#include <asm/cpu-features.h>
#include <asm/div64.h>
#include <asm/smtc_ipi.h>
#include <asm/time.h>

/*
 * forward reference
 */
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

int __weak rtc_mips_set_time(unsigned long sec)
{
	return 0;
}
EXPORT_SYMBOL(rtc_mips_set_time);

int __weak rtc_mips_set_mmss(unsigned long nowtime)
{
	return rtc_mips_set_time(nowtime);
}

int update_persistent_clock(struct timespec now)
{
	return rtc_mips_set_mmss(now.tv_sec);
}

int (*mips_timer_state)(void);

int null_perf_irq(void)
{
	return 0;
}

EXPORT_SYMBOL(null_perf_irq);

int (*perf_irq)(void) = null_perf_irq;

EXPORT_SYMBOL(perf_irq);

/*
 * time_init() - it does the following things.
 *
 * 1) plat_time_init() -
 * 	a) (optional) set up RTC routines,
 *      b) (optional) calibrate and set the mips_hpt_frequency
 *	    (only needed if you intended to use cpu counter as timer interrupt
 *	     source)
 * 2) calculate a couple of cached variables for later usage
 */

unsigned int mips_hpt_frequency;

void __init clocksource_set_clock(struct clocksource *cs, unsigned int clock)
{
	u64 temp;
	u32 shift;

	/* Find a shift value */
	for (shift = 32; shift > 0; shift--) {
		temp = (u64) NSEC_PER_SEC << shift;
		do_div(temp, clock);
		if ((temp >> 32) == 0)
			break;
	}
	cs->shift = shift;
	cs->mult = (u32) temp;
}

void __cpuinit clockevent_set_clock(struct clock_event_device *cd,
	unsigned int clock)
{
	u64 temp;
	u32 shift;

	/* Find a shift value */
	for (shift = 32; shift > 0; shift--) {
		temp = (u64) clock << shift;
		do_div(temp, NSEC_PER_SEC);
		if ((temp >> 32) == 0)
			break;
	}
	cd->shift = shift;
	cd->mult = (u32) temp;
}

/*
 * This function exists in order to cause an error due to a duplicate
 * definition if platform code should have its own implementation.  The hook
 * to use instead is plat_time_init.  plat_time_init does not receive the
 * irqaction pointer argument anymore.  This is because any function which
 * initializes an interrupt timer now takes care of its own request_irq rsp.
 * setup_irq calls and each clock_event_device should use its own
 * struct irqrequest.
 */
void __init plat_timer_setup(void)
{
	BUG();
}

static __init int cpu_has_mfc0_count_bug(void)
{
	switch (current_cpu_type()) {
	case CPU_R4000PC:
	case CPU_R4000SC:
	case CPU_R4000MC:
		/*
		 * V3.0 is documented as suffering from the mfc0 from count bug.
		 * Afaik this is the last version of the R4000.  Later versions
		 * were marketed as R4400.
		 */
		return 1;

	case CPU_R4400PC:
	case CPU_R4400SC:
	case CPU_R4400MC:
		/*
		 * The published errata for the R4400 upto 3.0 say the CPU
		 * has the mfc0 from count bug.
		 */
		if ((current_cpu_data.processor_id & 0xff) <= 0x30)
			return 1;

		/*
		 * we assume newer revisions are ok
		 */
		return 0;
	}

	return 0;
}

void __init time_init(void)
{
	plat_time_init();

	if (mips_clockevent_init() || !cpu_has_mfc0_count_bug())
		init_mips_clocksource();
}