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