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	.flags = IRQF_DISABLED,
48	.name = "timer",
49};
50
51/*
52 * timer_interrupt() needs to keep up the real-time clock,
53 * as well as call the "do_timer()" routine every clocktick
54 */
55static irqreturn_t timer_interrupt(int irq, void *dummy)
56{
57	profile_tick(CPU_PROFILING);
58	/*
59	 * Here we are in the timer irq handler. We just have irqs locally
60	 * disabled but we don't know if the timer_bh is running on the other
61	 * CPU. We need to avoid to SMP race with it. NOTE: we don't need
62	 * the irq version of write_lock because as just said we have irq
63	 * locally disabled. -arca
64	 */
65	write_seqlock(&xtime_lock);
66
67	do_timer(1);
68
69#ifdef CONFIG_HEARTBEAT
70	static unsigned short n;
71	n++;
72	__set_LEDS(n);
73#endif /* CONFIG_HEARTBEAT */
74
75	write_sequnlock(&xtime_lock);
76
77	update_process_times(user_mode(get_irq_regs()));
78
79	return IRQ_HANDLED;
80}
81
82void time_divisor_init(void)
83{
84	unsigned short base, pre, prediv;
85
86	/* set the scheduling timer going */
87	pre = 1;
88	prediv = 4;
89	base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
90
91	__set_TPRV(pre);
92	__set_TxCKSL_DATA(0, prediv);
93	__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
94	__set_TCSR_DATA(0, base & 0xff);
95	__set_TCSR_DATA(0, base >> 8);
96}
97
98
99void read_persistent_clock(struct timespec *ts)
100{
101	unsigned int year, mon, day, hour, min, sec;
102
103	extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
104
105	/* FIX by dqg : Set to zero for platforms that don't have tod */
106	/* without this time is undefined and can overflow time_t, causing  */
107	/* very strange errors */
108	year = 1980;
109	mon = day = 1;
110	hour = min = sec = 0;
111	arch_gettod (&year, &mon, &day, &hour, &min, &sec);
112
113	if ((year += 1900) < 1970)
114		year += 100;
115	ts->tv_sec = mktime(year, mon, day, hour, min, sec);
116	ts->tv_nsec = 0;
117}
118
119void time_init(void)
120{
121	/* install scheduling interrupt handler */
122	setup_irq(IRQ_CPU_TIMER0, &timer_irq);
123
124	time_divisor_init();
125}
126
127/*
128 * Scheduler clock - returns current time in nanosec units.
129 */
130unsigned long long sched_clock(void)
131{
132	return jiffies_64 * (1000000000 / HZ);
133}
134