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 /*
  94  * This version of gettimeofday has near microsecond resolution.
  95  */
  96 void do_gettimeofday (struct timeval *tv)
  97 {
  98 #if 0 /* DAVIDM later if possible */
  99         extern volatile unsigned long lost_ticks;
 100         unsigned long lost;
 101 #endif
 102         unsigned long flags;
 103         unsigned long usec, sec;
 104         unsigned long seq;
 105
 106         do {
 107                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 108
 109 #if 0
 110                 usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
 111 #else
 112                 usec = 0;
 113 #endif
 114 #if 0 /* DAVIDM later if possible */
 115                 lost = lost_ticks;
 116                 if (lost)
 117                         usec += lost * (1000000/HZ);
 118 #endif
 119                 sec = xtime.tv_sec;
 120                 usec += xtime.tv_nsec / 1000;
 121         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 122
 123         while (usec >= 1000000) {
 124                 usec -= 1000000;
 125                 sec++;
 126         }
 127
 128         tv->tv_sec = sec;
 129         tv->tv_usec = usec;
 130 }
 131
 132 EXPORT_SYMBOL(do_gettimeofday);
 133
 134 int do_settimeofday(struct timespec *tv)
 135 {
 136         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 137                 return -EINVAL;
 138
 139         write_seqlock_irq (&xtime_lock);
 140
 141         /* This is revolting. We need to set the xtime.tv_nsec
 142          * correctly. However, the value in this location is
 143          * is value at the last tick.
 144          * Discover what correction gettimeofday
 145          * would have done, and then undo it!
 146          */
 147 #if 0
 148         tv->tv_nsec -= mach_gettimeoffset() * 1000;
 149 #endif
 150
 151         while (tv->tv_nsec < 0) {
 152                 tv->tv_nsec += NSEC_PER_SEC;
 153                 tv->tv_sec--;
 154         }
 155
 156         xtime.tv_sec = tv->tv_sec;
 157         xtime.tv_nsec = tv->tv_nsec;
 158
 159         ntp_clear();
 160
 161         write_sequnlock_irq (&xtime_lock);
 162         clock_was_set();
 163         return 0;
 164 }
 165
 166 EXPORT_SYMBOL(do_settimeofday);
 167
 168 static int timer_dev_id;
 169 static struct irqaction timer_irqaction = {
 170         timer_interrupt,
 171         IRQF_DISABLED,
 172         CPU_MASK_NONE,
 173         "timer",
 174         &timer_dev_id,
 175         NULL
 176 };
 177
 178 void time_init (void)
 179 {
 180         mach_gettimeofday (&xtime);
 181         mach_sched_init (&timer_irqaction);
 182 }