arch/m68knommu/kernel/time.c

   1 /*
   2  *  linux/arch/m68knommu/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/config.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/param.h>
  19 #include <linux/string.h>
  20 #include <linux/mm.h>
  21 #include <linux/profile.h>
  22 #include <linux/time.h>
  23 #include <linux/timex.h>
  24
  25 #include <asm/machdep.h>
  26 #include <asm/io.h>
  27
  28 #define TICK_SIZE (tick_nsec / 1000)
  29
  30 u64 jiffies_64 = INITIAL_JIFFIES;
  31
  32 EXPORT_SYMBOL(jiffies_64);
  33
  34 extern unsigned long wall_jiffies;
  35
  36
  37 static inline int set_rtc_mmss(unsigned long nowtime)
  38 {
  39         if (mach_set_clock_mmss)
  40                 return mach_set_clock_mmss (nowtime);
  41         return -1;
  42 }
  43
  44 /*
  45  * timer_interrupt() needs to keep up the real-time clock,
  46  * as well as call the "do_timer()" routine every clocktick
  47  */
  48 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
  49 {
  50         /* last time the cmos clock got updated */
  51         static long last_rtc_update=0;
  52
  53         /* may need to kick the hardware timer */
  54         if (mach_tick)
  55           mach_tick();
  56
  57         write_seqlock(&xtime_lock);
  58
  59         do_timer(regs);
  60 #ifndef CONFIG_SMP
  61         update_process_times(user_mode(regs));
  62 #endif
  63         if (current->pid)
  64                 profile_tick(CPU_PROFILING, regs);
  65
  66         /*
  67          * If we have an externally synchronized Linux clock, then update
  68          * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
  69          * called as close as possible to 500 ms before the new second starts.
  70          */
  71         if ((time_status & STA_UNSYNC) == 0 &&
  72             xtime.tv_sec > last_rtc_update + 660 &&
  73             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
  74             (xtime.tv_nsec  / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
  75           if (set_rtc_mmss(xtime.tv_sec) == 0)
  76             last_rtc_update = xtime.tv_sec;
  77           else
  78             last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
  79         }
  80 #ifdef CONFIG_HEARTBEAT
  81         /* use power LED as a heartbeat instead -- much more useful
  82            for debugging -- based on the version for PReP by Cort */
  83         /* acts like an actual heart beat -- ie thump-thump-pause... */
  84         if (mach_heartbeat) {
  85             static unsigned cnt = 0, period = 0, dist = 0;
  86
  87             if (cnt == 0 || cnt == dist)
  88                 mach_heartbeat( 1 );
  89             else if (cnt == 7 || cnt == dist+7)
  90                 mach_heartbeat( 0 );
  91
  92             if (++cnt > period) {
  93                 cnt = 0;
  94                 /* The hyperbolic function below modifies the heartbeat period
  95                  * length in dependency of the current (5min) load. It goes
  96                  * through the points f(0)=126, f(1)=86, f(5)=51,
  97                  * f(inf)->30. */
  98                 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
  99                 dist = period / 4;
 100             }
 101         }
 102 #endif /* CONFIG_HEARTBEAT */
 103
 104         write_sequnlock(&xtime_lock);
 105         return(IRQ_HANDLED);
 106 }
 107
 108 void time_init(void)
 109 {
 110         unsigned int year, mon, day, hour, min, sec;
 111
 112         extern void arch_gettod(int *year, int *mon, int *day, int *hour,
 113                                 int *min, int *sec);
 114
 115         arch_gettod(&year, &mon, &day, &hour, &min, &sec);
 116
 117         if ((year += 1900) < 1970)
 118                 year += 100;
 119         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 120         xtime.tv_nsec = 0;
 121         wall_to_monotonic.tv_sec = -xtime.tv_sec;
 122
 123         mach_sched_init(timer_interrupt);
 124 }
 125
 126 /*
 127  * This version of gettimeofday has near microsecond resolution.
 128  */
 129 void do_gettimeofday(struct timeval *tv)
 130 {
 131         unsigned long flags;
 132         unsigned long lost, seq;
 133         unsigned long usec, sec;
 134
 135         do {
 136                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 137                 usec = mach_gettimeoffset ? mach_gettimeoffset() : 0;
 138                 lost = jiffies - wall_jiffies;
 139                 if (lost)
 140                         usec += lost * (1000000 / HZ);
 141                 sec = xtime.tv_sec;
 142                 usec += (xtime.tv_nsec / 1000);
 143         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 144
 145         while (usec >= 1000000) {
 146                 usec -= 1000000;
 147                 sec++;
 148         }
 149
 150         tv->tv_sec = sec;
 151         tv->tv_usec = usec;
 152 }
 153
 154 EXPORT_SYMBOL(do_gettimeofday);
 155
 156 int do_settimeofday(struct timespec *tv)
 157 {
 158         time_t wtm_sec, sec = tv->tv_sec;
 159         long wtm_nsec, nsec = tv->tv_nsec;
 160
 161         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 162                 return -EINVAL;
 163
 164         write_seqlock_irq(&xtime_lock);
 165         /*
 166          * This is revolting. We need to set the xtime.tv_usec
 167          * correctly. However, the value in this location is
 168          * is value at the last tick.
 169          * Discover what correction gettimeofday
 170          * would have done, and then undo it!
 171          */
 172         if (mach_gettimeoffset)
 173                 nsec -= (mach_gettimeoffset() * 1000);
 174
 175         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 176         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 177
 178         set_normalized_timespec(&xtime, sec, nsec);
 179         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 180
 181         time_adjust = 0;                /* stop active adjtime() */
 182         time_status |= STA_UNSYNC;
 183         time_maxerror = NTP_PHASE_LIMIT;
 184         time_esterror = NTP_PHASE_LIMIT;
 185         write_sequnlock_irq(&xtime_lock);
 186         clock_was_set();
 187         return 0;
 188 }
 189
 190 /*
 191  * Scheduler clock - returns current time in nanosec units.
 192  */
 193 unsigned long long sched_clock(void)
 194 {
 195         return (unsigned long long)jiffies * (1000000000 / HZ);
 196 }
 197
 198 EXPORT_SYMBOL(do_settimeofday);