arch/v850/kernel/time.c

   1 /*
   2  * linux/arch/v850/kernel/time.c -- Arch-dependent timer functions
   3  *
   4  *  Copyright (C) 1991, 1992, 1995, 2001, 2002  Linus Torvalds
   5  *
   6  * This file contains the v850-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/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/param.h>
  17 #include <linux/string.h>
  18 #include <linux/mm.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/time.h>
  21 #include <linux/timex.h>
  22 #include <linux/profile.h>
  23
  24 #include <asm/io.h>
  25
  26 #include "mach.h"
  27
  28 #define TICK_SIZE       (tick_nsec / 1000)
  29
  30 /*
  31  * timer_interrupt() needs to keep up the real-time clock,
  32  * as well as call the "do_timer()" routine every clocktick
  33  */
  34 static irqreturn_t timer_interrupt (int irq, void *dummy, struct pt_regs *regs)
  35 {
  36 #if 0
  37         /* last time the cmos clock got updated */
  38         static long last_rtc_update=0;
  39 #endif
  40
  41         /* may need to kick the hardware timer */
  42         if (mach_tick)
  43           mach_tick ();
  44
  45         do_timer (1);
  46 #ifndef CONFIG_SMP
  47         update_process_times(user_mode(regs));
  48 #endif
  49         profile_tick(CPU_PROFILING, regs);
  50 #if 0
  51         /*
  52          * If we have an externally synchronized Linux clock, then update
  53          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  54          * called as close as possible to 500 ms before the new second starts.
  55          */
  56         if (ntp_synced() &&
  57             xtime.tv_sec > last_rtc_update + 660 &&
  58             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  59             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
  60           if (set_rtc_mmss (xtime.tv_sec) == 0)
  61             last_rtc_update = xtime.tv_sec;
  62           else
  63             last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
  64         }
  65 #ifdef CONFIG_HEARTBEAT
  66         /* use power LED as a heartbeat instead -- much more useful
  67            for debugging -- based on the version for PReP by Cort */
  68         /* acts like an actual heart beat -- ie thump-thump-pause... */
  69         if (mach_heartbeat) {
  70             static unsigned cnt = 0, period = 0, dist = 0;
  71
  72             if (cnt == 0 || cnt == dist)
  73                 mach_heartbeat ( 1 );
  74             else if (cnt == 7 || cnt == dist+7)
  75                 mach_heartbeat ( 0 );
  76
  77             if (++cnt > period) {
  78                 cnt = 0;
  79                 /* The hyperbolic function below modifies the heartbeat period
  80                  * length in dependency of the current (5min) load. It goes
  81                  * through the points f(0)=126, f(1)=86, f(5)=51,
  82                  * f(inf)->30. */
  83                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  84                 dist = period / 4;
  85             }
  86         }
  87 #endif /* CONFIG_HEARTBEAT */
  88 #endif /* 0 */
  89
  90         return IRQ_HANDLED;
  91 }
  92
  93 static int timer_dev_id;
  94 static struct irqaction timer_irqaction = {
  95         timer_interrupt,
  96         IRQF_DISABLED,
  97         CPU_MASK_NONE,
  98         "timer",
  99         &timer_dev_id,
 100         NULL
 101 };
 102
 103 void time_init (void)
 104 {
 105         mach_gettimeofday (&xtime);
 106         mach_sched_init (&timer_irqaction);
 107 }