arch/h8300/kernel/time.c

   1 /*
   2  *  linux/arch/h8300/kernel/time.c
   3  *
   4  *  Yoshinori Sato <ysato@users.sourceforge.jp>
   5  *
   6  *  Copied/hacked from:
   7  *
   8  *  linux/arch/m68k/kernel/time.c
   9  *
  10  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
  11  *
  12  * This file contains the m68k-specific time handling details.
  13  * Most of the stuff is located in the machine specific files.
  14  *
  15  * 1997-09-10   Updated NTP code according to technical memorandum Jan '96
  16  *              "A Kernel Model for Precision Timekeeping" by Dave Mills
  17  */
  18
  19 #include <linux/errno.h>
  20 #include <linux/module.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/param.h>
  24 #include <linux/string.h>
  25 #include <linux/mm.h>
  26 #include <linux/timex.h>
  27 #include <linux/profile.h>
  28
  29 #include <asm/io.h>
  30 #include <asm/target_time.h>
  31
  32 #define TICK_SIZE (tick_nsec / 1000)
  33
  34 /*
  35  * timer_interrupt() needs to keep up the real-time clock,
  36  * as well as call the "do_timer()" routine every clocktick
  37  */
  38 static void timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
  39 {
  40         /* may need to kick the hardware timer */
  41         platform_timer_eoi();
  42
  43         do_timer(1);
  44 #ifndef CONFIG_SMP
  45         update_process_times(user_mode(regs));
  46 #endif
  47         profile_tick(CPU_PROFILING, regs);
  48 }
  49
  50 void time_init(void)
  51 {
  52         unsigned int year, mon, day, hour, min, sec;
  53
  54         /* FIX by dqg : Set to zero for platforms that don't have tod */
  55         /* without this time is undefined and can overflow time_t, causing  */
  56         /* very stange errors */
  57         year = 1980;
  58         mon = day = 1;
  59         hour = min = sec = 0;
  60         platform_gettod (&year, &mon, &day, &hour, &min, &sec);
  61
  62         if ((year += 1900) < 1970)
  63                 year += 100;
  64         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
  65         xtime.tv_nsec = 0;
  66
  67         platform_timer_setup(timer_interrupt);
  68 }
  69
  70 /*
  71  * This version of gettimeofday has near microsecond resolution.
  72  */
  73 void do_gettimeofday(struct timeval *tv)
  74 {
  75         unsigned long flags;
  76         unsigned long usec, sec;
  77
  78         read_lock_irqsave(&xtime_lock, flags);
  79         usec = 0;
  80         sec = xtime.tv_sec;
  81         usec += (xtime.tv_nsec / 1000);
  82         read_unlock_irqrestore(&xtime_lock, flags);
  83
  84         while (usec >= 1000000) {
  85                 usec -= 1000000;
  86                 sec++;
  87         }
  88
  89         tv->tv_sec = sec;
  90         tv->tv_usec = usec;
  91 }
  92
  93 EXPORT_SYMBOL(do_gettimeofday);
  94
  95 int do_settimeofday(struct timespec *tv)
  96 {
  97         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  98                 return -EINVAL;
  99
 100         write_lock_irq(&xtime_lock);
 101         /* This is revolting. We need to set the xtime.tv_usec
 102          * correctly. However, the value in this location is
 103          * is value at the last tick.
 104          * Discover what correction gettimeofday
 105          * would have done, and then undo it!
 106          */
 107         while (tv->tv_nsec < 0) {
 108                 tv->tv_nsec += NSEC_PER_SEC;
 109                 tv->tv_sec--;
 110         }
 111
 112         xtime.tv_sec = tv->tv_sec;
 113         xtime.tv_nsec = tv->tv_nsec;
 114         ntp_clear();
 115         write_sequnlock_irq(&xtime_lock);
 116         clock_was_set();
 117         return 0;
 118 }
 119
 120 EXPORT_SYMBOL(do_settimeofday);
 121
 122 unsigned long long sched_clock(void)
 123 {
 124         return (unsigned long long)jiffies * (1000000000 / HZ);
 125
 126 }