linux/arch/cris/kernel/time.c
<<
>>
Prefs
   1/*
   2 *  linux/arch/cris/kernel/time.c
   3 *
   4 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   5 *  Copyright (C) 1999, 2000, 2001 Axis Communications AB
   6 *
   7 * 1994-07-02    Alan Modra
   8 *      fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
   9 * 1995-03-26    Markus Kuhn
  10 *      fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
  11 *      precision CMOS clock update
  12 * 1996-05-03    Ingo Molnar
  13 *      fixed time warps in do_[slow|fast]_gettimeoffset()
  14 * 1997-09-10   Updated NTP code according to technical memorandum Jan '96
  15 *              "A Kernel Model for Precision Timekeeping" by Dave Mills
  16 *
  17 * Linux/CRIS specific code:
  18 *
  19 * Authors:    Bjorn Wesen
  20 *             Johan Adolfsson
  21 *
  22 */
  23
  24#include <asm/rtc.h>
  25#include <linux/errno.h>
  26#include <linux/module.h>
  27#include <linux/param.h>
  28#include <linux/jiffies.h>
  29#include <linux/bcd.h>
  30#include <linux/timex.h>
  31#include <linux/init.h>
  32#include <linux/profile.h>
  33#include <linux/sched.h>        /* just for sched_clock() - funny that */
  34
  35int have_rtc;  /* used to remember if we have an RTC or not */;
  36
  37#define TICK_SIZE tick
  38
  39extern unsigned long loops_per_jiffy; /* init/main.c */
  40unsigned long loops_per_usec;
  41
  42extern unsigned long do_slow_gettimeoffset(void);
  43static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
  44
  45/*
  46 * This version of gettimeofday has near microsecond resolution.
  47 *
  48 * Note: Division is quite slow on CRIS and do_gettimeofday is called
  49 *       rather often. Maybe we should do some kind of approximation here
  50 *       (a naive approximation would be to divide by 1024).
  51 */
  52void do_gettimeofday(struct timeval *tv)
  53{
  54        unsigned long flags;
  55        signed long usec, sec;
  56        local_irq_save(flags);
  57        usec = do_gettimeoffset();
  58
  59        /*
  60         * If time_adjust is negative then NTP is slowing the clock
  61         * so make sure not to go into next possible interval.
  62         * Better to lose some accuracy than have time go backwards..
  63         */
  64        if (unlikely(time_adjust < 0) && usec > tickadj)
  65                usec = tickadj;
  66
  67        sec = xtime.tv_sec;
  68        usec += xtime.tv_nsec / 1000;
  69        local_irq_restore(flags);
  70
  71        while (usec >= 1000000) {
  72                usec -= 1000000;
  73                sec++;
  74        }
  75
  76        tv->tv_sec = sec;
  77        tv->tv_usec = usec;
  78}
  79
  80EXPORT_SYMBOL(do_gettimeofday);
  81
  82int do_settimeofday(struct timespec *tv)
  83{
  84        time_t wtm_sec, sec = tv->tv_sec;
  85        long wtm_nsec, nsec = tv->tv_nsec;
  86
  87        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  88                return -EINVAL;
  89
  90        write_seqlock_irq(&xtime_lock);
  91        /*
  92         * This is revolting. We need to set "xtime" correctly. However, the
  93         * value in this location is the value at the most recent update of
  94         * wall time.  Discover what correction gettimeofday() would have
  95         * made, and then undo it!
  96         */
  97        nsec -= do_gettimeoffset() * NSEC_PER_USEC;
  98
  99        wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 100        wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 101
 102        set_normalized_timespec(&xtime, sec, nsec);
 103        set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 104
 105        ntp_clear();
 106        write_sequnlock_irq(&xtime_lock);
 107        clock_was_set();
 108        return 0;
 109}
 110
 111EXPORT_SYMBOL(do_settimeofday);
 112
 113
 114/*
 115 * BUG: This routine does not handle hour overflow properly; it just
 116 *      sets the minutes. Usually you'll only notice that after reboot!
 117 */
 118
 119int set_rtc_mmss(unsigned long nowtime)
 120{
 121        int retval = 0;
 122        int real_seconds, real_minutes, cmos_minutes;
 123
 124        printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);
 125
 126        if(!have_rtc)
 127                return 0;
 128
 129        cmos_minutes = CMOS_READ(RTC_MINUTES);
 130        BCD_TO_BIN(cmos_minutes);
 131
 132        /*
 133         * since we're only adjusting minutes and seconds,
 134         * don't interfere with hour overflow. This avoids
 135         * messing with unknown time zones but requires your
 136         * RTC not to be off by more than 15 minutes
 137         */
 138        real_seconds = nowtime % 60;
 139        real_minutes = nowtime / 60;
 140        if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 141                real_minutes += 30;             /* correct for half hour time zone */
 142        real_minutes %= 60;
 143
 144        if (abs(real_minutes - cmos_minutes) < 30) {
 145                BIN_TO_BCD(real_seconds);
 146                BIN_TO_BCD(real_minutes);
 147                CMOS_WRITE(real_seconds,RTC_SECONDS);
 148                CMOS_WRITE(real_minutes,RTC_MINUTES);
 149        } else {
 150                printk(KERN_WARNING
 151                       "set_rtc_mmss: can't update from %d to %d\n",
 152                       cmos_minutes, real_minutes);
 153                retval = -1;
 154        }
 155
 156        return retval;
 157}
 158
 159/* grab the time from the RTC chip */
 160
 161unsigned long
 162get_cmos_time(void)
 163{
 164        unsigned int year, mon, day, hour, min, sec;
 165
 166        sec = CMOS_READ(RTC_SECONDS);
 167        min = CMOS_READ(RTC_MINUTES);
 168        hour = CMOS_READ(RTC_HOURS);
 169        day = CMOS_READ(RTC_DAY_OF_MONTH);
 170        mon = CMOS_READ(RTC_MONTH);
 171        year = CMOS_READ(RTC_YEAR);
 172
 173        BCD_TO_BIN(sec);
 174        BCD_TO_BIN(min);
 175        BCD_TO_BIN(hour);
 176        BCD_TO_BIN(day);
 177        BCD_TO_BIN(mon);
 178        BCD_TO_BIN(year);
 179
 180        if ((year += 1900) < 1970)
 181                year += 100;
 182
 183        return mktime(year, mon, day, hour, min, sec);
 184}
 185
 186/* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
 187 * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
 188 */
 189
 190void
 191update_xtime_from_cmos(void)
 192{
 193        if(have_rtc) {
 194                xtime.tv_sec = get_cmos_time();
 195                xtime.tv_nsec = 0;
 196        }
 197}
 198
 199extern void cris_profile_sample(struct pt_regs* regs);
 200
 201void
 202cris_do_profile(struct pt_regs* regs)
 203{
 204
 205#ifdef CONFIG_SYSTEM_PROFILER
 206        cris_profile_sample(regs);
 207#endif
 208
 209#ifdef CONFIG_PROFILING
 210        profile_tick(CPU_PROFILING);
 211#endif
 212}
 213
 214unsigned long long sched_clock(void)
 215{
 216        return (unsigned long long)jiffies * (1000000000 / HZ) +
 217                get_ns_in_jiffie();
 218}
 219
 220static int
 221__init init_udelay(void)
 222{
 223        loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
 224        return 0;
 225}
 226
 227__initcall(init_udelay);
 228