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/config.h> /* CONFIG_HEARTBEAT */
  14 #include <linux/errno.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/param.h>
  18 #include <linux/string.h>
  19 #include <linux/mm.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/time.h>
  22 #include <linux/timex.h>
  23 #include <linux/profile.h>
  24
  25 #include <asm/io.h>
  26
  27 #include "mach.h"
  28
  29 #define TICK_SIZE       (tick_nsec / 1000)
  30
  31 /*
  32  * Scheduler clock - returns current time in nanosec units.
  33  */
  34 unsigned long long sched_clock(void)
  35 {
  36         return (unsigned long long)jiffies * (1000000000 / HZ);
  37 }
  38
  39 /*
  40  * timer_interrupt() needs to keep up the real-time clock,
  41  * as well as call the "do_timer()" routine every clocktick
  42  */
  43 static irqreturn_t timer_interrupt (int irq, void *dummy, struct pt_regs *regs)
  44 {
  45 #if 0
  46         /* last time the cmos clock got updated */
  47         static long last_rtc_update=0;
  48 #endif
  49
  50         /* may need to kick the hardware timer */
  51         if (mach_tick)
  52           mach_tick ();
  53
  54         do_timer (regs);
  55 #ifndef CONFIG_SMP
  56         update_process_times(user_mode(regs));
  57 #endif
  58         profile_tick(CPU_PROFILING, regs);
  59 #if 0
  60         /*
  61          * If we have an externally synchronized Linux clock, then update
  62          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  63          * called as close as possible to 500 ms before the new second starts.
  64          */
  65         if (ntp_synced() &&
  66             xtime.tv_sec > last_rtc_update + 660 &&
  67             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  68             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
  69           if (set_rtc_mmss (xtime.tv_sec) == 0)
  70             last_rtc_update = xtime.tv_sec;
  71           else
  72             last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
  73         }
  74 #ifdef CONFIG_HEARTBEAT
  75         /* use power LED as a heartbeat instead -- much more useful
  76            for debugging -- based on the version for PReP by Cort */
  77         /* acts like an actual heart beat -- ie thump-thump-pause... */
  78         if (mach_heartbeat) {
  79             static unsigned cnt = 0, period = 0, dist = 0;
  80
  81             if (cnt == 0 || cnt == dist)
  82                 mach_heartbeat ( 1 );
  83             else if (cnt == 7 || cnt == dist+7)
  84                 mach_heartbeat ( 0 );
  85
  86             if (++cnt > period) {
  87                 cnt = 0;
  88                 /* The hyperbolic function below modifies the heartbeat period
  89                  * length in dependency of the current (5min) load. It goes
  90                  * through the points f(0)=126, f(1)=86, f(5)=51,
  91                  * f(inf)->30. */
  92                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  93                 dist = period / 4;
  94             }
  95         }
  96 #endif /* CONFIG_HEARTBEAT */
  97 #endif /* 0 */
  98
  99         return IRQ_HANDLED;
 100 }
 101
 102 /*
 103  * This version of gettimeofday has near microsecond resolution.
 104  */
 105 void do_gettimeofday (struct timeval *tv)
 106 {
 107 #if 0 /* DAVIDM later if possible */
 108         extern volatile unsigned long lost_ticks;
 109         unsigned long lost;
 110 #endif
 111         unsigned long flags;
 112         unsigned long usec, sec;
 113         unsigned long seq;
 114
 115         do {
 116                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 117
 118 #if 0
 119                 usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
 120 #else
 121                 usec = 0;
 122 #endif
 123 #if 0 /* DAVIDM later if possible */
 124                 lost = lost_ticks;
 125                 if (lost)
 126                         usec += lost * (1000000/HZ);
 127 #endif
 128                 sec = xtime.tv_sec;
 129                 usec += xtime.tv_nsec / 1000;
 130         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 131
 132         while (usec >= 1000000) {
 133                 usec -= 1000000;
 134                 sec++;
 135         }
 136
 137         tv->tv_sec = sec;
 138         tv->tv_usec = usec;
 139 }
 140
 141 EXPORT_SYMBOL(do_gettimeofday);
 142
 143 int do_settimeofday(struct timespec *tv)
 144 {
 145         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 146                 return -EINVAL;
 147
 148         write_seqlock_irq (&xtime_lock);
 149
 150         /* This is revolting. We need to set the xtime.tv_nsec
 151          * correctly. However, the value in this location is
 152          * is value at the last tick.
 153          * Discover what correction gettimeofday
 154          * would have done, and then undo it!
 155          */
 156 #if 0
 157         tv->tv_nsec -= mach_gettimeoffset() * 1000;
 158 #endif
 159
 160         while (tv->tv_nsec < 0) {
 161                 tv->tv_nsec += NSEC_PER_SEC;
 162                 tv->tv_sec--;
 163         }
 164
 165         xtime.tv_sec = tv->tv_sec;
 166         xtime.tv_nsec = tv->tv_nsec;
 167
 168         ntp_clear();
 169
 170         write_sequnlock_irq (&xtime_lock);
 171         clock_was_set();
 172         return 0;
 173 }
 174
 175 EXPORT_SYMBOL(do_settimeofday);
 176
 177 static int timer_dev_id;
 178 static struct irqaction timer_irqaction = {
 179         timer_interrupt,
 180         IRQF_DISABLED,
 181         CPU_MASK_NONE,
 182         "timer",
 183         &timer_dev_id,
 184         NULL
 185 };
 186
 187 void time_init (void)
 188 {
 189         mach_gettimeofday (&xtime);
 190         mach_sched_init (&timer_irqaction);
 191 }