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