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time.c

/*
 *  linux/arch/cris/kernel/time.c
 *
 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
 *  Copyright (C) 1999, 2000, 2001 Axis Communications AB
 *
 * 1994-07-02    Alan Modra
 *    fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
 * 1995-03-26    Markus Kuhn
 *      fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
 *      precision CMOS clock update
 * 1996-05-03    Ingo Molnar
 *      fixed time warps in do_[slow|fast]_gettimeoffset()
 * 1997-09-10     Updated NTP code according to technical memorandum Jan '96
 *          "A Kernel Model for Precision Timekeeping" by Dave Mills
 *
 * Linux/CRIS specific code:
 *
 * Authors:    Bjorn Wesen
 *             Johan Adolfsson
 *
 */

#include <asm/rtc.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/jiffies.h>
#include <linux/bcd.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/profile.h>
#include <linux/sched.h>      /* just for sched_clock() - funny that */

int have_rtc;  /* used to remember if we have an RTC or not */;

#define TICK_SIZE tick

extern unsigned long loops_per_jiffy; /* init/main.c */
unsigned long loops_per_usec;

extern unsigned long do_slow_gettimeoffset(void);
static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;

/*
 * This version of gettimeofday has near microsecond resolution.
 *
 * Note: Division is quite slow on CRIS and do_gettimeofday is called
 *       rather often. Maybe we should do some kind of approximation here
 *       (a naive approximation would be to divide by 1024).
 */
void do_gettimeofday(struct timeval *tv)
{
      unsigned long flags;
      signed long usec, sec;
      local_irq_save(flags);
      usec = do_gettimeoffset();

        /*
       * If time_adjust is negative then NTP is slowing the clock
       * so make sure not to go into next possible interval.
       * Better to lose some accuracy than have time go backwards..
       */
      if (unlikely(time_adjust < 0) && usec > tickadj)
            usec = tickadj;

      sec = xtime.tv_sec;
      usec += xtime.tv_nsec / 1000;
      local_irq_restore(flags);

      while (usec >= 1000000) {
            usec -= 1000000;
            sec++;
      }

      tv->tv_sec = sec;
      tv->tv_usec = usec;
}

EXPORT_SYMBOL(do_gettimeofday);

int do_settimeofday(struct timespec *tv)
{
      time_t wtm_sec, sec = tv->tv_sec;
      long wtm_nsec, nsec = tv->tv_nsec;

      if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
            return -EINVAL;

      write_seqlock_irq(&xtime_lock);
      /*
       * This is revolting. We need to set "xtime" correctly. However, the
       * value in this location is the value at the most recent update of
       * wall time.  Discover what correction gettimeofday() would have
       * made, and then undo it!
       */
      nsec -= do_gettimeoffset() * NSEC_PER_USEC;

      wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
      wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

      set_normalized_timespec(&xtime, sec, nsec);
      set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);

      ntp_clear();
      write_sequnlock_irq(&xtime_lock);
      clock_was_set();
      return 0;
}

EXPORT_SYMBOL(do_settimeofday);


/*
 * BUG: This routine does not handle hour overflow properly; it just
 *      sets the minutes. Usually you'll only notice that after reboot!
 */

int set_rtc_mmss(unsigned long nowtime)
{
      int retval = 0;
      int real_seconds, real_minutes, cmos_minutes;

      printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);

      if(!have_rtc)
            return 0;

      cmos_minutes = CMOS_READ(RTC_MINUTES);
      cmos_minutes = bcd2bin(cmos_minutes);

      /*
       * since we're only adjusting minutes and seconds,
       * don't interfere with hour overflow. This avoids
       * messing with unknown time zones but requires your
       * RTC not to be off by more than 15 minutes
       */
      real_seconds = nowtime % 60;
      real_minutes = nowtime / 60;
      if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
            real_minutes += 30;           /* correct for half hour time zone */
      real_minutes %= 60;

      if (abs(real_minutes - cmos_minutes) < 30) {
            real_seconds = bin2bcd(real_seconds);
            real_minutes = bin2bcd(real_minutes);
            CMOS_WRITE(real_seconds,RTC_SECONDS);
            CMOS_WRITE(real_minutes,RTC_MINUTES);
      } else {
            printk(KERN_WARNING
                   "set_rtc_mmss: can't update from %d to %d\n",
                   cmos_minutes, real_minutes);
            retval = -1;
      }

      return retval;
}

/* grab the time from the RTC chip */

unsigned long
get_cmos_time(void)
{
      unsigned int year, mon, day, hour, min, sec;

      sec = CMOS_READ(RTC_SECONDS);
      min = CMOS_READ(RTC_MINUTES);
      hour = CMOS_READ(RTC_HOURS);
      day = CMOS_READ(RTC_DAY_OF_MONTH);
      mon = CMOS_READ(RTC_MONTH);
      year = CMOS_READ(RTC_YEAR);

      sec = bcd2bin(sec);
      min = bcd2bin(min);
      hour = bcd2bin(hour);
      day = bcd2bin(day);
      mon = bcd2bin(mon);
      year = bcd2bin(year);

      if ((year += 1900) < 1970)
            year += 100;

      return mktime(year, mon, day, hour, min, sec);
}

/* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
 * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
 */

void
update_xtime_from_cmos(void)
{
      if(have_rtc) {
            xtime.tv_sec = get_cmos_time();
            xtime.tv_nsec = 0;
      }
}

extern void cris_profile_sample(struct pt_regs* regs);

void
cris_do_profile(struct pt_regs* regs)
{

#ifdef CONFIG_SYSTEM_PROFILER
        cris_profile_sample(regs);
#endif

#ifdef CONFIG_PROFILING
      profile_tick(CPU_PROFILING);
#endif
}

unsigned long long sched_clock(void)
{
      return (unsigned long long)jiffies * (1000000000 / HZ) +
            get_ns_in_jiffie();
}

static int
__init init_udelay(void)
{
      loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
      return 0;
}

__initcall(init_udelay);

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