LXR linux/arch/m68k/kernel/time

   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);
 115