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
  35 u64 jiffies_64 = INITIAL_JIFFIES;
  36
  37 EXPORT_SYMBOL(jiffies_64);
  38
  39 int have_rtc;  /* used to remember if we have an RTC or not */;
  40
  41 #define TICK_SIZE tick
  42
  43 extern unsigned long wall_jiffies;
  44 extern unsigned long loops_per_jiffy; /* init/main.c */
  45 unsigned long loops_per_usec;
  46
  47 extern unsigned long do_slow_gettimeoffset(void);
  48 static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
  49
  50 /*
  51  * This version of gettimeofday has near microsecond resolution.
  52  *
  53  * Note: Division is quite slow on CRIS and do_gettimeofday is called
  54  *       rather often. Maybe we should do some kind of approximation here
  55  *       (a naive approximation would be to divide by 1024).
  56  */
  57 void do_gettimeofday(struct timeval *tv)
  58 {
  59         unsigned long flags;
  60         signed long usec, sec;
  61         local_irq_save(flags);
  62         local_irq_disable();
  63         usec = do_gettimeoffset();
  64         {
  65                 unsigned long lost = jiffies - wall_jiffies;
  66                 if (lost)
  67                         usec += lost * (1000000 / HZ);
  68         }
  69
  70         /*
  71          * If time_adjust is negative then NTP is slowing the clock
  72          * so make sure not to go into next possible interval.
  73          * Better to lose some accuracy than have time go backwards..
  74          */
  75         if (unlikely(time_adjust < 0) && usec > tickadj)
  76                 usec = tickadj;
  77
  78         sec = xtime.tv_sec;
  79         usec += xtime.tv_nsec / 1000;
  80         local_irq_restore(flags);
  81
  82         while (usec >= 1000000) {
  83                 usec -= 1000000;
  84                 sec++;
  85         }
  86
  87         tv->tv_sec = sec;
  88         tv->tv_usec = usec;
  89 }
  90
  91 EXPORT_SYMBOL(do_gettimeofday);
  92
  93 int do_settimeofday(struct timespec *tv)
  94 {
  95         time_t wtm_sec, sec = tv->tv_sec;
  96         long wtm_nsec, nsec = tv->tv_nsec;
  97
  98         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
  99                 return -EINVAL;
 100
 101         write_seqlock_irq(&xtime_lock);
 102         /*
 103          * This is revolting. We need to set "xtime" correctly. However, the
 104          * value in this location is the value at the most recent update of
 105          * wall time.  Discover what correction gettimeofday() would have
 106          * made, and then undo it!
 107          */
 108         nsec -= do_gettimeoffset() * NSEC_PER_USEC;
 109         nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
 110
 111         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 112         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 113
 114         set_normalized_timespec(&xtime, sec, nsec);
 115         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 116
 117         ntp_clear();
 118         write_sequnlock_irq(&xtime_lock);
 119         clock_was_set();
 120         return 0;
 121 }
 122
 123 EXPORT_SYMBOL(do_settimeofday);
 124
 125
 126 /*
 127  * BUG: This routine does not handle hour overflow properly; it just
 128  *      sets the minutes. Usually you'll only notice that after reboot!
 129  */
 130
 131 int set_rtc_mmss(unsigned long nowtime)
 132 {
 133         int retval = 0;
 134         int real_seconds, real_minutes, cmos_minutes;
 135
 136         printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);
 137
 138         if(!have_rtc)
 139                 return 0;
 140
 141         cmos_minutes = CMOS_READ(RTC_MINUTES);
 142         BCD_TO_BIN(cmos_minutes);
 143
 144         /*
 145          * since we're only adjusting minutes and seconds,
 146          * don't interfere with hour overflow. This avoids
 147          * messing with unknown time zones but requires your
 148          * RTC not to be off by more than 15 minutes
 149          */
 150         real_seconds = nowtime % 60;
 151         real_minutes = nowtime / 60;
 152         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 153                 real_minutes += 30;             /* correct for half hour time zone */
 154         real_minutes %= 60;
 155
 156         if (abs(real_minutes - cmos_minutes) < 30) {
 157                 BIN_TO_BCD(real_seconds);
 158                 BIN_TO_BCD(real_minutes);
 159                 CMOS_WRITE(real_seconds,RTC_SECONDS);
 160                 CMOS_WRITE(real_minutes,RTC_MINUTES);
 161         } else {
 162                 printk(KERN_WARNING
 163                        "set_rtc_mmss: can't update from %d to %d\n",
 164                        cmos_minutes, real_minutes);
 165                 retval = -1;
 166         }
 167
 168         return retval;
 169 }
 170
 171 /* grab the time from the RTC chip */
 172
 173 unsigned long
 174 get_cmos_time(void)
 175 {
 176         unsigned int year, mon, day, hour, min, sec;
 177
 178         sec = CMOS_READ(RTC_SECONDS);
 179         min = CMOS_READ(RTC_MINUTES);
 180         hour = CMOS_READ(RTC_HOURS);
 181         day = CMOS_READ(RTC_DAY_OF_MONTH);
 182         mon = CMOS_READ(RTC_MONTH);
 183         year = CMOS_READ(RTC_YEAR);
 184
 185         printk(KERN_DEBUG
 186                "rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n",
 187                sec, min, hour, day, mon, year);
 188
 189         BCD_TO_BIN(sec);
 190         BCD_TO_BIN(min);
 191         BCD_TO_BIN(hour);
 192         BCD_TO_BIN(day);
 193         BCD_TO_BIN(mon);
 194         BCD_TO_BIN(year);
 195
 196         if ((year += 1900) < 1970)
 197                 year += 100;
 198
 199         return mktime(year, mon, day, hour, min, sec);
 200 }
 201
 202 /* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
 203  * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
 204  */
 205
 206 void
 207 update_xtime_from_cmos(void)
 208 {
 209         if(have_rtc) {
 210                 xtime.tv_sec = get_cmos_time();
 211                 xtime.tv_nsec = 0;
 212         }
 213 }
 214
 215 extern void cris_profile_sample(struct pt_regs* regs);
 216
 217 void
 218 cris_do_profile(struct pt_regs* regs)
 219 {
 220
 221 #if CONFIG_SYSTEM_PROFILER
 222         cris_profile_sample(regs);
 223 #endif
 224
 225 #if CONFIG_PROFILING
 226         profile_tick(CPU_PROFILING, regs);
 227 #endif
 228 }
 229
 230 /*
 231  * Scheduler clock - returns current time in nanosec units.
 232  */
 233 unsigned long long sched_clock(void)
 234 {
 235         return (unsigned long long)jiffies * (1000000000 / HZ);
 236 }
 237
 238 static int
 239 __init init_udelay(void)
 240 {
 241         loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
 242         return 0;
 243 }
 244
 245 __initcall(init_udelay);