1/*
  2 *  linux/arch/m68k/kernel/time.c
  3 *
  4 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
  5 *
  6 * This file contains the m68k-specific time handling details.
  7 * Most of the stuff is located in the machine specific files.
  8 *
  9 * 1997-09-10	Updated NTP code according to technical memorandum Jan '96
 10 *		"A Kernel Model for Precision Timekeeping" by Dave Mills
 11 */
 12
 13#include <linux/errno.h>
 14#include <linux/module.h>
 15#include <linux/sched.h>
 16#include <linux/kernel.h>
 17#include <linux/param.h>
 18#include <linux/string.h>
 19#include <linux/mm.h>
 20#include <linux/rtc.h>
 21#include <linux/platform_device.h>
 22
 23#include <asm/machdep.h>
 24#include <asm/io.h>
 25#include <asm/irq_regs.h>
 26
 27#include <linux/time.h>
 28#include <linux/timex.h>
 29#include <linux/profile.h>
 30
 31static inline int set_rtc_mmss(unsigned long nowtime)
 32{
 33  if (mach_set_clock_mmss)
 34    return mach_set_clock_mmss (nowtime);
 35  return -1;
 36}
 37
 38/*
 39 * timer_interrupt() needs to keep up the real-time clock,
 40 * as well as call the "xtime_update()" routine every clocktick
 41 */
 42static irqreturn_t timer_interrupt(int irq, void *dummy)
 43{
 44	xtime_update(1);
 45	update_process_times(user_mode(get_irq_regs()));
 46	profile_tick(CPU_PROFILING);
 47
 48#ifdef CONFIG_HEARTBEAT
 49	/* use power LED as a heartbeat instead -- much more useful
 50	   for debugging -- based on the version for PReP by Cort */
 51	/* acts like an actual heart beat -- ie thump-thump-pause... */
 52	if (mach_heartbeat) {
 53	    static unsigned cnt = 0, period = 0, dist = 0;
 54
 55	    if (cnt == 0 || cnt == dist)
 56		mach_heartbeat( 1 );
 57	    else if (cnt == 7 || cnt == dist+7)
 58		mach_heartbeat( 0 );
 59
 60	    if (++cnt > period) {
 61		cnt = 0;
 62		/* The hyperbolic function below modifies the heartbeat period
 63		 * length in dependency of the current (5min) load. It goes
 64		 * through the points f(0)=126, f(1)=86, f(5)=51,
 65		 * f(inf)->30. */
 66		period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
 67		dist = period / 4;
 68	    }
 69	}
 70#endif /* CONFIG_HEARTBEAT */
 71	return IRQ_HANDLED;
 72}
 73
 74void read_persistent_clock(struct timespec *ts)
 75{
 76	struct rtc_time time;
 77	ts->tv_sec = 0;
 78	ts->tv_nsec = 0;
 79
 80	if (mach_hwclk) {
 81		mach_hwclk(0, &time);
 82
 83		if ((time.tm_year += 1900) < 1970)
 84			time.tm_year += 100;
 85		ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
 86				      time.tm_hour, time.tm_min, time.tm_sec);
 87	}
 88}
 89
 90void __init time_init(void)
 91{
 92	mach_sched_init(timer_interrupt);
 93}
 94
 95u32 arch_gettimeoffset(void)
 96{
 97	return mach_gettimeoffset() * 1000;
 98}
 99
100static int __init rtc_init(void)
101{
102	struct platform_device *pdev;
103
104	if (!mach_hwclk)
105		return -ENODEV;
106
107	pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
108	if (IS_ERR(pdev))
109		return PTR_ERR(pdev);
110
111	return 0;
112}
113
114module_init(rtc_init);