summaryrefslogtreecommitdiffstats
path: root/arch/frv/kernel/time.c
blob: 69f6a4ef5d61b35c67323a85485e1cebedff7a43 (plain)
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
/* time.c: FRV arch-specific time handling
 *
 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * - Derived from arch/m68k/kernel/time.c
 *
 * 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/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/profile.h>
#include <linux/irq.h>
#include <linux/mm.h>

#include <asm/io.h>
#include <asm/timer-regs.h>
#include <asm/mb-regs.h>
#include <asm/mb86943a.h>

#include <linux/timex.h>

#define TICK_SIZE (tick_nsec / 1000)

unsigned long __nongprelbss __clkin_clock_speed_HZ;
unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
unsigned long __nongprelbss __res_bus_clock_speed_HZ;
unsigned long __nongprelbss __sdram_clock_speed_HZ;
unsigned long __nongprelbss __core_bus_clock_speed_HZ;
unsigned long __nongprelbss __core_clock_speed_HZ;
unsigned long __nongprelbss __dsu_clock_speed_HZ;
unsigned long __nongprelbss __serial_clock_speed_HZ;
unsigned long __delay_loops_MHz;

static irqreturn_t timer_interrupt(int irq, void *dummy);

static struct irqaction timer_irq  = {
	.handler = timer_interrupt,
	.flags = IRQF_DISABLED,
	.mask = CPU_MASK_NONE,
	.name = "timer",
};

static inline int set_rtc_mmss(unsigned long nowtime)
{
	return -1;
}

/*
 * timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */
static irqreturn_t timer_interrupt(int irq, void *dummy)
{
	/* last time the cmos clock got updated */
	static long last_rtc_update = 0;

	profile_tick(CPU_PROFILING);
	/*
	 * Here we are in the timer irq handler. We just have irqs locally
	 * disabled but we don't know if the timer_bh is running on the other
	 * CPU. We need to avoid to SMP race with it. NOTE: we don't need
	 * the irq version of write_lock because as just said we have irq
	 * locally disabled. -arca
	 */
	write_seqlock(&xtime_lock);

	do_timer(1);

	/*
	 * If we have an externally synchronized Linux clock, then update
	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	 * called as close as possible to 500 ms before the new second starts.
	 */
	if (ntp_synced() &&
	    xtime.tv_sec > last_rtc_update + 660 &&
	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
	    (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2
	    ) {
		if (set_rtc_mmss(xtime.tv_sec) == 0)
			last_rtc_update = xtime.tv_sec;
		else
			last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
	}

#ifdef CONFIG_HEARTBEAT
	static unsigned short n;
	n++;
	__set_LEDS(n);
#endif /* CONFIG_HEARTBEAT */

	write_sequnlock(&xtime_lock);

	update_process_times(user_mode(get_irq_regs()));

	return IRQ_HANDLED;
}

void time_divisor_init(void)
{
	unsigned short base, pre, prediv;

	/* set the scheduling timer going */
	pre = 1;
	prediv = 4;
	base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);

	__set_TPRV(pre);
	__set_TxCKSL_DATA(0, prediv);
	__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
	__set_TCSR_DATA(0, base & 0xff);
	__set_TCSR_DATA(0, base >> 8);
}

void time_init(void)
{
	unsigned int year, mon, day, hour, min, sec;

	extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);

	/* FIX by dqg : Set to zero for platforms that don't have tod */
	/* without this time is undefined and can overflow time_t, causing  */
	/* very strange errors */
	year = 1980;
	mon = day = 1;
	hour = min = sec = 0;
	arch_gettod (&year, &mon, &day, &hour, &min, &sec);

	if ((year += 1900) < 1970)
		year += 100;
	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
	xtime.tv_nsec = 0;

	/* install scheduling interrupt handler */
	setup_irq(IRQ_CPU_TIMER0, &timer_irq);

	time_divisor_init();
}

/*
 * Scheduler clock - returns current time in nanosec units.
 */
unsigned long long sched_clock(void)
{
	return jiffies_64 * (1000000000 / HZ);
}
OpenPOWER on IntegriCloud