1/* time.c: FRV arch-specific time handling
2 *
3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from arch/m68k/kernel/time.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/module.h>
14#include <linux/errno.h>
15#include <linux/sched.h>
16#include <linux/kernel.h>
17#include <linux/param.h>
18#include <linux/string.h>
19#include <linux/interrupt.h>
20#include <linux/profile.h>
21#include <linux/irq.h>
22#include <linux/mm.h>
23
24#include <asm/io.h>
25#include <asm/timer-regs.h>
26#include <asm/mb-regs.h>
27#include <asm/mb86943a.h>
28
29#include <linux/timex.h>
30
31#define TICK_SIZE (tick_nsec / 1000)
32
33unsigned long __nongprelbss __clkin_clock_speed_HZ;
34unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
35unsigned long __nongprelbss __res_bus_clock_speed_HZ;
36unsigned long __nongprelbss __sdram_clock_speed_HZ;
37unsigned long __nongprelbss __core_bus_clock_speed_HZ;
38unsigned long __nongprelbss __core_clock_speed_HZ;
39unsigned long __nongprelbss __dsu_clock_speed_HZ;
40unsigned long __nongprelbss __serial_clock_speed_HZ;
41unsigned long __delay_loops_MHz;
42
43static irqreturn_t timer_interrupt(int irq, void *dummy);
44
45static struct irqaction timer_irq  = {
46	.handler = timer_interrupt,
47	.name = "timer",
48};
49
50/*
51 * timer_interrupt() needs to keep up the real-time clock,
52 * as well as call the "xtime_update()" routine every clocktick
53 */
54static irqreturn_t timer_interrupt(int irq, void *dummy)
55{
56	profile_tick(CPU_PROFILING);
57
58	xtime_update(1);
59
60#ifdef CONFIG_HEARTBEAT
61	static unsigned short n;
62	n++;
63	__set_LEDS(n);
64#endif /* CONFIG_HEARTBEAT */
65
66	update_process_times(user_mode(get_irq_regs()));
67
68	return IRQ_HANDLED;
69}
70
71void time_divisor_init(void)
72{
73	unsigned short base, pre, prediv;
74
75	/* set the scheduling timer going */
76	pre = 1;
77	prediv = 4;
78	base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
79
80	__set_TPRV(pre);
81	__set_TxCKSL_DATA(0, prediv);
82	__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
83	__set_TCSR_DATA(0, base & 0xff);
84	__set_TCSR_DATA(0, base >> 8);
85}
86
87
88void read_persistent_clock(struct timespec *ts)
89{
90	unsigned int year, mon, day, hour, min, sec;
91
92	extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
93
94	/* FIX by dqg : Set to zero for platforms that don't have tod */
95	/* without this time is undefined and can overflow time_t, causing  */
96	/* very strange errors */
97	year = 1980;
98	mon = day = 1;
99	hour = min = sec = 0;
100	arch_gettod (&year, &mon, &day, &hour, &min, &sec);
101
102	if ((year += 1900) < 1970)
103		year += 100;
104	ts->tv_sec = mktime(year, mon, day, hour, min, sec);
105	ts->tv_nsec = 0;
106}
107
108void time_init(void)
109{
110	/* install scheduling interrupt handler */
111	setup_irq(IRQ_CPU_TIMER0, &timer_irq);
112
113	time_divisor_init();
114}
115
116/*
117 * Scheduler clock - returns current time in nanosec units.
118 */
119unsigned long long sched_clock(void)
120{
121	return jiffies_64 * (1000000000 / HZ);
122}
123