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