LXR linux/arch/m68k/kernel/time.c

   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/export.h>
  15#include <linux/module.h>
  16#include <linux/sched.h>
  17#include <linux/kernel.h>
  18#include <linux/param.h>
  19#include <linux/string.h>
  20#include <linux/mm.h>
  21#include <linux/rtc.h>
  22#include <linux/platform_device.h>
  23
  24#include <asm/machdep.h>
  25#include <asm/io.h>
  26#include <asm/irq_regs.h>
  27
  28#include <linux/time.h>
  29#include <linux/timex.h>
  30#include <linux/profile.h>
  31
  32
  33unsigned long (*mach_random_get_entropy)(void);
  34EXPORT_SYMBOL_GPL(mach_random_get_entropy);
  35
  36
  37/*
  38 * timer_interrupt() needs to keep up the real-time clock,
  39 * as well as call the "xtime_update()" routine every clocktick
  40 */
  41static irqreturn_t timer_interrupt(int irq, void *dummy)
  42{
  43        xtime_update(1);
  44        update_process_times(user_mode(get_irq_regs()));
  45        profile_tick(CPU_PROFILING);
  46
  47#ifdef CONFIG_HEARTBEAT
  48        /* use power LED as a heartbeat instead -- much more useful
  49           for debugging -- based on the version for PReP by Cort */
  50        /* acts like an actual heart beat -- ie thump-thump-pause... */
  51        if (mach_heartbeat) {
  52            static unsigned cnt = 0, period = 0, dist = 0;
  53
  54            if (cnt == 0 || cnt == dist)
  55                mach_heartbeat( 1 );
  56            else if (cnt == 7 || cnt == dist+7)
  57                mach_heartbeat( 0 );
  58
  59            if (++cnt > period) {
  60                cnt = 0;
  61                /* The hyperbolic function below modifies the heartbeat period
  62                 * length in dependency of the current (5min) load. It goes
  63                 * through the points f(0)=126, f(1)=86, f(5)=51,
  64                 * f(inf)->30. */
  65                period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  66                dist = period / 4;
  67            }
  68        }
  69#endif /* CONFIG_HEARTBEAT */
  70        return IRQ_HANDLED;
  71}
  72
  73void read_persistent_clock(struct timespec *ts)
  74{
  75        struct rtc_time time;
  76        ts->tv_sec = 0;
  77        ts->tv_nsec = 0;
  78
  79        if (mach_hwclk) {
  80                mach_hwclk(0, &time);
  81
  82                if ((time.tm_year += 1900) < 1970)
  83                        time.tm_year += 100;
  84                ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
  85                                      time.tm_hour, time.tm_min, time.tm_sec);
  86        }
  87}
  88
  89#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
  90
  91static int __init rtc_init(void)
  92{
  93        struct platform_device *pdev;
  94
  95        if (!mach_hwclk)
  96                return -ENODEV;
  97
  98        pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
  99        return PTR_ERR_OR_ZERO(pdev);
 100}
 101
 102module_init(rtc_init);
 103
 104#endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
 105
 106void __init time_init(void)
 107{
 108        mach_sched_init(timer_interrupt);
 109}
 110