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 u64 jiffies_64 = INITIAL_JIFFIES;
  30
  31 EXPORT_SYMBOL(jiffies_64);
  32
  33 #define TICK_SIZE       (tick_nsec / 1000)
  34
  35 /*
  36  * Scheduler clock - returns current time in nanosec units.
  37  */
  38 unsigned long long sched_clock(void)
  39 {
  40         return (unsigned long long)jiffies * (1000000000 / HZ);
  41 }
  42
  43 /*
  44  * timer_interrupt() needs to keep up the real-time clock,
  45  * as well as call the "do_timer()" routine every clocktick
  46  */
  47 static irqreturn_t timer_interrupt (int irq, void *dummy, struct pt_regs *regs)
  48 {
  49 #if 0
  50         /* last time the cmos clock got updated */
  51         static long last_rtc_update=0;
  52 #endif
  53
  54         /* may need to kick the hardware timer */
  55         if (mach_tick)
  56           mach_tick ();
  57
  58         do_timer (regs);
  59 #ifndef CONFIG_SMP
  60         update_process_times(user_mode(regs));
  61 #endif
  62         profile_tick(CPU_PROFILING, regs);
  63 #if 0
  64         /*
  65          * If we have an externally synchronized Linux clock, then update
  66          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  67          * called as close as possible to 500 ms before the new second starts.
  68          */
  69         if ((time_status & STA_UNSYNC) == 0 &&
  70             xtime.tv_sec > last_rtc_update + 660 &&
  71             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  72             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
  73           if (set_rtc_mmss (xtime.tv_sec) == 0)
  74             last_rtc_update = xtime.tv_sec;
  75           else
  76             last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
  77         }
  78 #ifdef CONFIG_HEARTBEAT
  79         /* use power LED as a heartbeat instead -- much more useful
  80            for debugging -- based on the version for PReP by Cort */
  81         /* acts like an actual heart beat -- ie thump-thump-pause... */
  82         if (mach_heartbeat) {
  83             static unsigned cnt = 0, period = 0, dist = 0;
  84
  85             if (cnt == 0 || cnt == dist)
  86                 mach_heartbeat ( 1 );
  87             else if (cnt == 7 || cnt == dist+7)
  88                 mach_heartbeat ( 0 );
  89
  90             if (++cnt > period) {
  91                 cnt = 0;
  92                 /* The hyperbolic function below modifies the heartbeat period
  93                  * length in dependency of the current (5min) load. It goes
  94                  * through the points f(0)=126, f(1)=86, f(5)=51,
  95                  * f(inf)->30. */
  96                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  97                 dist = period / 4;
  98             }
  99         }
 100 #endif /* CONFIG_HEARTBEAT */
 101 #endif /* 0 */
 102
 103         return IRQ_HANDLED;
 104 }
 105
 106 /*
 107  * This version of gettimeofday has near microsecond resolution.
 108  */
 109 void do_gettimeofday (struct timeval *tv)
 110 {
 111 #if 0 /* DAVIDM later if possible */
 112         extern volatile unsigned long lost_ticks;
 113         unsigned long lost;
 114 #endif
 115         unsigned long flags;
 116         unsigned long usec, sec;
 117         unsigned long seq;
 118
 119         do {
 120                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 121
 122 #if 0
 123                 usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
 124 #else
 125                 usec = 0;
 126 #endif
 127 #if 0 /* DAVIDM later if possible */
 128                 lost = lost_ticks;
 129                 if (lost)
 130                         usec += lost * (1000000/HZ);
 131 #endif
 132                 sec = xtime.tv_sec;
 133                 usec += xtime.tv_nsec / 1000;
 134         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 135
 136         while (usec >= 1000000) {
 137                 usec -= 1000000;
 138                 sec++;
 139         }
 140
 141         tv->tv_sec = sec;
 142         tv->tv_usec = usec;
 143 }
 144
 145 EXPORT_SYMBOL(do_gettimeofday);
 146
 147 int do_settimeofday(struct timespec *tv)
 148 {
 149         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 150                 return -EINVAL;
 151
 152         write_seqlock_irq (&xtime_lock);
 153
 154         /* This is revolting. We need to set the xtime.tv_nsec
 155          * correctly. However, the value in this location is
 156          * is value at the last tick.
 157          * Discover what correction gettimeofday
 158          * would have done, and then undo it!
 159          */
 160 #if 0
 161         tv->tv_nsec -= mach_gettimeoffset() * 1000;
 162 #endif
 163
 164         while (tv->tv_nsec < 0) {
 165                 tv->tv_nsec += NSEC_PER_SEC;
 166                 tv->tv_sec--;
 167         }
 168
 169         xtime.tv_sec = tv->tv_sec;
 170         xtime.tv_nsec = tv->tv_nsec;
 171
 172         time_adjust = 0;                /* stop active adjtime () */
 173         time_status |= STA_UNSYNC;
 174         time_maxerror = NTP_PHASE_LIMIT;
 175         time_esterror = NTP_PHASE_LIMIT;
 176
 177         write_sequnlock_irq (&xtime_lock);
 178         clock_was_set();
 179         return 0;
 180 }
 181
 182 EXPORT_SYMBOL(do_settimeofday);
 183
 184 static int timer_dev_id;
 185 static struct irqaction timer_irqaction = {
 186         timer_interrupt,
 187         SA_INTERRUPT,
 188         CPU_MASK_NONE,
 189         "timer",
 190         &timer_dev_id,
 191         NULL
 192 };
 193
 194 void time_init (void)
 195 {
 196         mach_gettimeofday (&xtime);
 197         mach_sched_init (&timer_irqaction);
 198 }