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 static 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 "do_timer()" routine every clocktick
  41  */
  42 static irqreturn_t timer_interrupt(int irq, void *dummy)
  43 {
  44         do_timer(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
  74 void 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
  90 void __init time_init(void)
  91 {
  92         mach_sched_init(timer_interrupt);
  93 }
  94
  95 u32 arch_gettimeoffset(void)
  96 {
  97         return mach_gettimeoffset() * 1000;
  98 }
  99
 100 static 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
 114 module_init(rtc_init);