arch/cris/kernel/time.c

   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
  35 int have_rtc;  /* used to remember if we have an RTC or not */;
  36
  37 #define TICK_SIZE tick
  38
  39 extern unsigned long loops_per_jiffy; /* init/main.c */
  40 unsigned long loops_per_usec;
  41
  42 extern unsigned long do_slow_gettimeoffset(void);
  43 static 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  */
  52 void 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
  80 EXPORT_SYMBOL(do_gettimeofday);
  81
  82 int 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
 111 EXPORT_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
 119 int 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
 161 unsigned long
 162 get_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
 190 void
 191 update_xtime_from_cmos(void)
 192 {
 193         if(have_rtc) {
 194                 xtime.tv_sec = get_cmos_time();
 195                 xtime.tv_nsec = 0;
 196         }
 197 }
 198
 199 extern void cris_profile_sample(struct pt_regs* regs);
 200
 201 void
 202 cris_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
 214 unsigned long long sched_clock(void)
 215 {
 216         return (unsigned long long)jiffies * (1000000000 / HZ) +
 217                 get_ns_in_jiffie();
 218 }
 219
 220 static 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);