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         usec = do_gettimeoffset();
  59
  60         /*
  61          * If time_adjust is negative then NTP is slowing the clock
  62          * so make sure not to go into next possible interval.
  63          * Better to lose some accuracy than have time go backwards..
  64          */
  65         if (unlikely(time_adjust < 0) && usec > tickadj)
  66                 usec = tickadj;
  67
  68         sec = xtime.tv_sec;
  69         usec += xtime.tv_nsec / 1000;
  70         local_irq_restore(flags);
  71
  72         while (usec >= 1000000) {
  73                 usec -= 1000000;
  74                 sec++;
  75         }
  76
  77         tv->tv_sec = sec;
  78         tv->tv_usec = usec;
  79 }
  80
  81 EXPORT_SYMBOL(do_gettimeofday);
  82
  83 int do_settimeofday(struct timespec *tv)
  84 {
  85         time_t wtm_sec, sec = tv->tv_sec;
  86         long wtm_nsec, nsec = tv->tv_nsec;
  87
  88         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  89                 return -EINVAL;
  90
  91         write_seqlock_irq(&xtime_lock);
  92         /*
  93          * This is revolting. We need to set "xtime" correctly. However, the
  94          * value in this location is the value at the most recent update of
  95          * wall time.  Discover what correction gettimeofday() would have
  96          * made, and then undo it!
  97          */
  98         nsec -= do_gettimeoffset() * NSEC_PER_USEC;
  99
 100         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 101         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 102
 103         set_normalized_timespec(&xtime, sec, nsec);
 104         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 105
 106         ntp_clear();
 107         write_sequnlock_irq(&xtime_lock);
 108         clock_was_set();
 109         return 0;
 110 }
 111
 112 EXPORT_SYMBOL(do_settimeofday);
 113
 114
 115 /*
 116  * BUG: This routine does not handle hour overflow properly; it just
 117  *      sets the minutes. Usually you'll only notice that after reboot!
 118  */
 119
 120 int set_rtc_mmss(unsigned long nowtime)
 121 {
 122         int retval = 0;
 123         int real_seconds, real_minutes, cmos_minutes;
 124
 125         printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);
 126
 127         if(!have_rtc)
 128                 return 0;
 129
 130         cmos_minutes = CMOS_READ(RTC_MINUTES);
 131         BCD_TO_BIN(cmos_minutes);
 132
 133         /*
 134          * since we're only adjusting minutes and seconds,
 135          * don't interfere with hour overflow. This avoids
 136          * messing with unknown time zones but requires your
 137          * RTC not to be off by more than 15 minutes
 138          */
 139         real_seconds = nowtime % 60;
 140         real_minutes = nowtime / 60;
 141         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 142                 real_minutes += 30;             /* correct for half hour time zone */
 143         real_minutes %= 60;
 144
 145         if (abs(real_minutes - cmos_minutes) < 30) {
 146                 BIN_TO_BCD(real_seconds);
 147                 BIN_TO_BCD(real_minutes);
 148                 CMOS_WRITE(real_seconds,RTC_SECONDS);
 149                 CMOS_WRITE(real_minutes,RTC_MINUTES);
 150         } else {
 151                 printk(KERN_WARNING
 152                        "set_rtc_mmss: can't update from %d to %d\n",
 153                        cmos_minutes, real_minutes);
 154                 retval = -1;
 155         }
 156
 157         return retval;
 158 }
 159
 160 /* grab the time from the RTC chip */
 161
 162 unsigned long
 163 get_cmos_time(void)
 164 {
 165         unsigned int year, mon, day, hour, min, sec;
 166
 167         sec = CMOS_READ(RTC_SECONDS);
 168         min = CMOS_READ(RTC_MINUTES);
 169         hour = CMOS_READ(RTC_HOURS);
 170         day = CMOS_READ(RTC_DAY_OF_MONTH);
 171         mon = CMOS_READ(RTC_MONTH);
 172         year = CMOS_READ(RTC_YEAR);
 173
 174         printk(KERN_DEBUG
 175                "rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n",
 176                sec, min, hour, day, mon, year);
 177
 178         BCD_TO_BIN(sec);
 179         BCD_TO_BIN(min);
 180         BCD_TO_BIN(hour);
 181         BCD_TO_BIN(day);
 182         BCD_TO_BIN(mon);
 183         BCD_TO_BIN(year);
 184
 185         if ((year += 1900) < 1970)
 186                 year += 100;
 187
 188         return mktime(year, mon, day, hour, min, sec);
 189 }
 190
 191 /* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
 192  * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
 193  */
 194
 195 void
 196 update_xtime_from_cmos(void)
 197 {
 198         if(have_rtc) {
 199                 xtime.tv_sec = get_cmos_time();
 200                 xtime.tv_nsec = 0;
 201         }
 202 }
 203
 204 extern void cris_profile_sample(struct pt_regs* regs);
 205
 206 void
 207 cris_do_profile(struct pt_regs* regs)
 208 {
 209
 210 #if CONFIG_SYSTEM_PROFILER
 211         cris_profile_sample(regs);
 212 #endif
 213
 214 #if CONFIG_PROFILING
 215         profile_tick(CPU_PROFILING, regs);
 216 #endif
 217 }
 218
 219 /*
 220  * Scheduler clock - returns current time in nanosec units.
 221  */
 222 unsigned long long sched_clock(void)
 223 {
 224         return (unsigned long long)jiffies * (1000000000 / HZ);
 225 }
 226
 227 static int
 228 __init init_udelay(void)
 229 {
 230         loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
 231         return 0;
 232 }
 233
 234 __initcall(init_udelay);