arch/cris/kernel/time.c

   1 /* $Id: time.c,v 1.18 2005/03/04 08:16:17 starvik Exp $
   2  *
   3  *  linux/arch/cris/kernel/time.c
   4  *
   5  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   6  *  Copyright (C) 1999, 2000, 2001 Axis Communications AB
   7  *
   8  * 1994-07-02    Alan Modra
   9  *      fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
  10  * 1995-03-26    Markus Kuhn
  11  *      fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
  12  *      precision CMOS clock update
  13  * 1996-05-03    Ingo Molnar
  14  *      fixed time warps in do_[slow|fast]_gettimeoffset()
  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  * Linux/CRIS specific code:
  19  *
  20  * Authors:    Bjorn Wesen
  21  *             Johan Adolfsson
  22  *
  23  */
  24
  25 #include <asm/rtc.h>
  26 #include <linux/errno.h>
  27 #include <linux/module.h>
  28 #include <linux/param.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/bcd.h>
  31 #include <linux/timex.h>
  32 #include <linux/init.h>
  33 #include <linux/profile.h>
  34 #include <linux/sched.h>        /* just for sched_clock() - funny that */
  35
  36 int have_rtc;  /* used to remember if we have an RTC or not */;
  37
  38 #define TICK_SIZE tick
  39
  40 extern unsigned long loops_per_jiffy; /* init/main.c */
  41 unsigned long loops_per_usec;
  42
  43 extern unsigned long do_slow_gettimeoffset(void);
  44 static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
  45
  46 /*
  47  * This version of gettimeofday has near microsecond resolution.
  48  *
  49  * Note: Division is quite slow on CRIS and do_gettimeofday is called
  50  *       rather often. Maybe we should do some kind of approximation here
  51  *       (a naive approximation would be to divide by 1024).
  52  */
  53 void do_gettimeofday(struct timeval *tv)
  54 {
  55         unsigned long flags;
  56         signed long usec, sec;
  57         local_irq_save(flags);
  58         local_irq_disable();
  59         usec = do_gettimeoffset();
  60
  61         /*
  62          * If time_adjust is negative then NTP is slowing the clock
  63          * so make sure not to go into next possible interval.
  64          * Better to lose some accuracy than have time go backwards..
  65          */
  66         if (unlikely(time_adjust < 0) && usec > tickadj)
  67                 usec = tickadj;
  68
  69         sec = xtime.tv_sec;
  70         usec += xtime.tv_nsec / 1000;
  71         local_irq_restore(flags);
  72
  73         while (usec >= 1000000) {
  74                 usec -= 1000000;
  75                 sec++;
  76         }
  77
  78         tv->tv_sec = sec;
  79         tv->tv_usec = usec;
  80 }
  81
  82 EXPORT_SYMBOL(do_gettimeofday);
  83
  84 int do_settimeofday(struct timespec *tv)
  85 {
  86         time_t wtm_sec, sec = tv->tv_sec;
  87         long wtm_nsec, nsec = tv->tv_nsec;
  88
  89         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  90                 return -EINVAL;
  91
  92         write_seqlock_irq(&xtime_lock);
  93         /*
  94          * This is revolting. We need to set "xtime" correctly. However, the
  95          * value in this location is the value at the most recent update of
  96          * wall time.  Discover what correction gettimeofday() would have
  97          * made, and then undo it!
  98          */
  99         nsec -= do_gettimeoffset() * NSEC_PER_USEC;
 100
 101         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 102         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 103
 104         set_normalized_timespec(&xtime, sec, nsec);
 105         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 106
 107         ntp_clear();
 108         write_sequnlock_irq(&xtime_lock);
 109         clock_was_set();
 110         return 0;
 111 }
 112
 113 EXPORT_SYMBOL(do_settimeofday);
 114
 115
 116 /*
 117  * BUG: This routine does not handle hour overflow properly; it just
 118  *      sets the minutes. Usually you'll only notice that after reboot!
 119  */
 120
 121 int set_rtc_mmss(unsigned long nowtime)
 122 {
 123         int retval = 0;
 124         int real_seconds, real_minutes, cmos_minutes;
 125
 126         printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);
 127
 128         if(!have_rtc)
 129                 return 0;
 130
 131         cmos_minutes = CMOS_READ(RTC_MINUTES);
 132         BCD_TO_BIN(cmos_minutes);
 133
 134         /*
 135          * since we're only adjusting minutes and seconds,
 136          * don't interfere with hour overflow. This avoids
 137          * messing with unknown time zones but requires your
 138          * RTC not to be off by more than 15 minutes
 139          */
 140         real_seconds = nowtime % 60;
 141         real_minutes = nowtime / 60;
 142         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 143                 real_minutes += 30;             /* correct for half hour time zone */
 144         real_minutes %= 60;
 145
 146         if (abs(real_minutes - cmos_minutes) < 30) {
 147                 BIN_TO_BCD(real_seconds);
 148                 BIN_TO_BCD(real_minutes);
 149                 CMOS_WRITE(real_seconds,RTC_SECONDS);
 150                 CMOS_WRITE(real_minutes,RTC_MINUTES);
 151         } else {
 152                 printk(KERN_WARNING
 153                        "set_rtc_mmss: can't update from %d to %d\n",
 154                        cmos_minutes, real_minutes);
 155                 retval = -1;
 156         }
 157
 158         return retval;
 159 }
 160
 161 /* grab the time from the RTC chip */
 162
 163 unsigned long
 164 get_cmos_time(void)
 165 {
 166         unsigned int year, mon, day, hour, min, sec;
 167
 168         sec = CMOS_READ(RTC_SECONDS);
 169         min = CMOS_READ(RTC_MINUTES);
 170         hour = CMOS_READ(RTC_HOURS);
 171         day = CMOS_READ(RTC_DAY_OF_MONTH);
 172         mon = CMOS_READ(RTC_MONTH);
 173         year = CMOS_READ(RTC_YEAR);
 174
 175         printk(KERN_DEBUG
 176                "rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n",
 177                sec, min, hour, day, mon, year);
 178
 179         BCD_TO_BIN(sec);
 180         BCD_TO_BIN(min);
 181         BCD_TO_BIN(hour);
 182         BCD_TO_BIN(day);
 183         BCD_TO_BIN(mon);
 184         BCD_TO_BIN(year);
 185
 186         if ((year += 1900) < 1970)
 187                 year += 100;
 188
 189         return mktime(year, mon, day, hour, min, sec);
 190 }
 191
 192 /* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
 193  * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
 194  */
 195
 196 void
 197 update_xtime_from_cmos(void)
 198 {
 199         if(have_rtc) {
 200                 xtime.tv_sec = get_cmos_time();
 201                 xtime.tv_nsec = 0;
 202         }
 203 }
 204
 205 extern void cris_profile_sample(struct pt_regs* regs);
 206
 207 void
 208 cris_do_profile(struct pt_regs* regs)
 209 {
 210
 211 #if CONFIG_SYSTEM_PROFILER
 212         cris_profile_sample(regs);
 213 #endif
 214
 215 #if CONFIG_PROFILING
 216         profile_tick(CPU_PROFILING, regs);
 217 #endif
 218 }
 219
 220 /*
 221  * Scheduler clock - returns current time in nanosec units.
 222  */
 223 unsigned long long sched_clock(void)
 224 {
 225         return (unsigned long long)jiffies * (1000000000 / HZ);
 226 }
 227
 228 static int
 229 __init init_udelay(void)
 230 {
 231         loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
 232         return 0;
 233 }
 234
 235 __initcall(init_udelay);