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 "xtime_update()" routine every clocktick
 54 */
 55static irqreturn_t timer_interrupt(int irq, void *dummy)
 56{
 57	profile_tick(CPU_PROFILING);
 58
 59	xtime_update(1);
 60
 61#ifdef CONFIG_HEARTBEAT
 62	static unsigned short n;
 63	n++;
 64	__set_LEDS(n);
 65#endif /* CONFIG_HEARTBEAT */
 66
 67	update_process_times(user_mode(get_irq_regs()));
 68
 69	return IRQ_HANDLED;
 70}
 71
 72void time_divisor_init(void)
 73{
 74	unsigned short base, pre, prediv;
 75
 76	/* set the scheduling timer going */
 77	pre = 1;
 78	prediv = 4;
 79	base = __res_bus_clock_speed_HZ / pre / HZ / (1 << prediv);
 80
 81	__set_TPRV(pre);
 82	__set_TxCKSL_DATA(0, prediv);
 83	__set_TCTR(TCTR_SC_CTR0 | TCTR_RL_RW_LH8 | TCTR_MODE_2);
 84	__set_TCSR_DATA(0, base & 0xff);
 85	__set_TCSR_DATA(0, base >> 8);
 86}
 87
 88
 89void read_persistent_clock(struct timespec *ts)
 90{
 91	unsigned int year, mon, day, hour, min, sec;
 92
 93	extern void arch_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec);
 94
 95	/* FIX by dqg : Set to zero for platforms that don't have tod */
 96	/* without this time is undefined and can overflow time_t, causing  */
 97	/* very strange errors */
 98	year = 1980;
 99	mon = day = 1;
100	hour = min = sec = 0;
101	arch_gettod (&year, &mon, &day, &hour, &min, &sec);
102
103	if ((year += 1900) < 1970)
104		year += 100;
105	ts->tv_sec = mktime(year, mon, day, hour, min, sec);
106	ts->tv_nsec = 0;
107}
108
109void time_init(void)
110{
111	/* install scheduling interrupt handler */
112	setup_irq(IRQ_CPU_TIMER0, &timer_irq);
113
114	time_divisor_init();
115}
116
117/*
118 * Scheduler clock - returns current time in nanosec units.
119 */
120unsigned long long sched_clock(void)
121{
122	return jiffies_64 * (1000000000 / HZ);
123}