ntp: support for TAI
[safe/jmp/linux-2.6] / kernel / time / ntp.c
index 87aa5ff..10fe17d 100644 (file)
 
 #include <linux/mm.h>
 #include <linux/time.h>
+#include <linux/timer.h>
 #include <linux/timex.h>
 #include <linux/jiffies.h>
 #include <linux/hrtimer.h>
-
-#include <asm/div64.h>
+#include <linux/capability.h>
+#include <linux/math64.h>
 #include <asm/timex.h>
 
 /*
@@ -34,31 +35,69 @@ static u64 tick_length, tick_length_base;
 /* TIME_ERROR prevents overwriting the CMOS clock */
 static int time_state = TIME_OK;       /* clock synchronization status */
 int time_status = STA_UNSYNC;          /* clock status bits            */
-static s64 time_offset;                /* time adjustment (ns)         */
+static long time_tai;                  /* TAI offset (s)               */
+static s64 time_offset;                        /* time adjustment (ns)         */
 static long time_constant = 2;         /* pll time constant            */
 long time_maxerror = NTP_PHASE_LIMIT;  /* maximum error (us)           */
 long time_esterror = NTP_PHASE_LIMIT;  /* estimated error (us)         */
-long time_freq;                                /* frequency offset (scaled ppm)*/
+static s64 time_freq;                  /* frequency offset (scaled ns/s)*/
 static long time_reftime;              /* time at last adjustment (s)  */
 long time_adjust;
-
-#define CLOCK_TICK_OVERFLOW    (LATCH * HZ - CLOCK_TICK_RATE)
-#define CLOCK_TICK_ADJUST      (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
-                                       (s64)CLOCK_TICK_RATE)
+static long ntp_tick_adj;
 
 static void ntp_update_frequency(void)
 {
        u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
                                << TICK_LENGTH_SHIFT;
-       second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
-       second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
+       second_length += (s64)ntp_tick_adj << TICK_LENGTH_SHIFT;
+       second_length += time_freq;
 
        tick_length_base = second_length;
 
-       do_div(second_length, HZ);
-       tick_nsec = second_length >> TICK_LENGTH_SHIFT;
+       tick_nsec = div_u64(second_length, HZ) >> TICK_LENGTH_SHIFT;
+       tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ);
+}
+
+static void ntp_update_offset(long offset)
+{
+       long mtemp;
+       s64 freq_adj;
+
+       if (!(time_status & STA_PLL))
+               return;
+
+       if (!(time_status & STA_NANO))
+               offset *= NSEC_PER_USEC;
+
+       /*
+        * Scale the phase adjustment and
+        * clamp to the operating range.
+        */
+       offset = min(offset, MAXPHASE);
+       offset = max(offset, -MAXPHASE);
+
+       /*
+        * Select how the frequency is to be controlled
+        * and in which mode (PLL or FLL).
+        */
+       if (time_status & STA_FREQHOLD || time_reftime == 0)
+               time_reftime = xtime.tv_sec;
+       mtemp = xtime.tv_sec - time_reftime;
+       time_reftime = xtime.tv_sec;
+
+       freq_adj = (s64)offset * mtemp;
+       freq_adj <<= TICK_LENGTH_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant);
+       time_status &= ~STA_MODE;
+       if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
+               freq_adj += div_s64((s64)offset << (TICK_LENGTH_SHIFT - SHIFT_FLL),
+                                   mtemp);
+               time_status |= STA_MODE;
+       }
+       freq_adj += time_freq;
+       freq_adj = min(freq_adj, MAXFREQ_SCALED);
+       time_freq = max(freq_adj, -MAXFREQ_SCALED);
 
-       do_div(tick_length_base, NTP_INTERVAL_FREQ);
+       time_offset = div_s64((s64)offset << TICK_LENGTH_SHIFT, NTP_INTERVAL_FREQ);
 }
 
 /**
@@ -89,10 +128,10 @@ void ntp_clear(void)
  */
 void second_overflow(void)
 {
-       long time_adj;
+       s64 time_adj;
 
        /* Bump the maxerror field */
-       time_maxerror += MAXFREQ >> SHIFT_USEC;
+       time_maxerror += MAXFREQ / NSEC_PER_USEC;
        if (time_maxerror > NTP_PHASE_LIMIT) {
                time_maxerror = NTP_PHASE_LIMIT;
                time_status |= STA_UNSYNC;
@@ -116,13 +155,7 @@ void second_overflow(void)
                if (xtime.tv_sec % 86400 == 0) {
                        xtime.tv_sec--;
                        wall_to_monotonic.tv_sec++;
-                       /*
-                        * The timer interpolator will make time change
-                        * gradually instead of an immediate jump by one second
-                        */
-                       time_interpolator_update(-NSEC_PER_SEC);
                        time_state = TIME_OOP;
-                       clock_was_set();
                        printk(KERN_NOTICE "Clock: inserting leap second "
                                        "23:59:60 UTC\n");
                }
@@ -130,24 +163,20 @@ void second_overflow(void)
        case TIME_DEL:
                if ((xtime.tv_sec + 1) % 86400 == 0) {
                        xtime.tv_sec++;
+                       time_tai--;
                        wall_to_monotonic.tv_sec--;
-                       /*
-                        * Use of time interpolator for a gradual change of
-                        * time
-                        */
-                       time_interpolator_update(NSEC_PER_SEC);
                        time_state = TIME_WAIT;
-                       clock_was_set();
                        printk(KERN_NOTICE "Clock: deleting leap second "
                                        "23:59:59 UTC\n");
                }
                break;
        case TIME_OOP:
+               time_tai++;
                time_state = TIME_WAIT;
                break;
        case TIME_WAIT:
                if (!(time_status & (STA_INS | STA_DEL)))
-               time_state = TIME_OK;
+                       time_state = TIME_OK;
        }
 
        /*
@@ -157,7 +186,7 @@ void second_overflow(void)
        tick_length = tick_length_base;
        time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
        time_offset -= time_adj;
-       tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);
+       tick_length += time_adj;
 
        if (unlikely(time_adjust)) {
                if (time_adjust > MAX_TICKADJ) {
@@ -187,19 +216,71 @@ u64 current_tick_length(void)
        return tick_length;
 }
 
+#ifdef CONFIG_GENERIC_CMOS_UPDATE
+
+/* Disable the cmos update - used by virtualization and embedded */
+int no_sync_cmos_clock  __read_mostly;
+
+static void sync_cmos_clock(unsigned long dummy);
+
+static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
+
+static void sync_cmos_clock(unsigned long dummy)
+{
+       struct timespec now, next;
+       int fail = 1;
+
+       /*
+        * If we have an externally synchronized Linux clock, then update
+        * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
+        * called as close as possible to 500 ms before the new second starts.
+        * This code is run on a timer.  If the clock is set, that timer
+        * may not expire at the correct time.  Thus, we adjust...
+        */
+       if (!ntp_synced())
+               /*
+                * Not synced, exit, do not restart a timer (if one is
+                * running, let it run out).
+                */
+               return;
+
+       getnstimeofday(&now);
+       if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
+               fail = update_persistent_clock(now);
+
+       next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+       if (next.tv_nsec <= 0)
+               next.tv_nsec += NSEC_PER_SEC;
+
+       if (!fail)
+               next.tv_sec = 659;
+       else
+               next.tv_sec = 0;
+
+       if (next.tv_nsec >= NSEC_PER_SEC) {
+               next.tv_sec++;
+               next.tv_nsec -= NSEC_PER_SEC;
+       }
+       mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
+}
 
-void __attribute__ ((weak)) notify_arch_cmos_timer(void)
+static void notify_cmos_timer(void)
 {
-       return;
+       if (!no_sync_cmos_clock)
+               mod_timer(&sync_cmos_timer, jiffies + 1);
 }
 
+#else
+static inline void notify_cmos_timer(void) { }
+#endif
+
 /* adjtimex mainly allows reading (and writing, if superuser) of
  * kernel time-keeping variables. used by xntpd.
  */
 int do_adjtimex(struct timex *txc)
 {
-       long mtemp, save_adjust, rem;
-       s64 freq_adj, temp64;
+       struct timespec ts;
+       long save_adjust;
        int result;
 
        /* In order to modify anything, you gotta be super-user! */
@@ -208,15 +289,11 @@ int do_adjtimex(struct timex *txc)
 
        /* Now we validate the data before disabling interrupts */
 
-       if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
-         /* singleshot must not be used with any other mode bits */
-               if (txc->modes != ADJ_OFFSET_SINGLESHOT)
-                       return -EINVAL;
-
-       if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
-         /* adjustment Offset limited to +- .512 seconds */
-               if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
+       if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) {
+               /* singleshot must not be used with any other mode bits */
+               if (txc->modes & ~ADJ_OFFSET_SS_READ)
                        return -EINVAL;
+       }
 
        /* if the quartz is off by more than 10% something is VERY wrong ! */
        if (txc->modes & ADJ_TICK)
@@ -225,126 +302,88 @@ int do_adjtimex(struct timex *txc)
                        return -EINVAL;
 
        write_seqlock_irq(&xtime_lock);
-       result = time_state;    /* mostly `TIME_OK' */
 
        /* Save for later - semantics of adjtime is to return old value */
        save_adjust = time_adjust;
 
-#if 0  /* STA_CLOCKERR is never set yet */
-       time_status &= ~STA_CLOCKERR;           /* reset STA_CLOCKERR */
-#endif
        /* If there are input parameters, then process them */
-       if (txc->modes)
-       {
-           if (txc->modes & ADJ_STATUS)        /* only set allowed bits */
-               time_status =  (txc->status & ~STA_RONLY) |
-                             (time_status & STA_RONLY);
-
-           if (txc->modes & ADJ_FREQUENCY) {   /* p. 22 */
-               if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
-                   result = -EINVAL;
-                   goto leave;
-               }
-               time_freq = ((s64)txc->freq * NSEC_PER_USEC)
-                               >> (SHIFT_USEC - SHIFT_NSEC);
-           }
-
-           if (txc->modes & ADJ_MAXERROR) {
-               if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
-                   result = -EINVAL;
-                   goto leave;
+       if (txc->modes) {
+               if (txc->modes & ADJ_STATUS) {
+                       if ((time_status & STA_PLL) &&
+                           !(txc->status & STA_PLL)) {
+                               time_state = TIME_OK;
+                               time_status = STA_UNSYNC;
+                       }
+                       /* only set allowed bits */
+                       time_status &= STA_RONLY;
+                       time_status |= txc->status & ~STA_RONLY;
                }
-               time_maxerror = txc->maxerror;
-           }
 
-           if (txc->modes & ADJ_ESTERROR) {
-               if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
-                   result = -EINVAL;
-                   goto leave;
+               if (txc->modes & ADJ_NANO)
+                       time_status |= STA_NANO;
+               if (txc->modes & ADJ_MICRO)
+                       time_status &= ~STA_NANO;
+
+               if (txc->modes & ADJ_FREQUENCY) {
+                       time_freq = (s64)txc->freq * PPM_SCALE;
+                       time_freq = min(time_freq, MAXFREQ_SCALED);
+                       time_freq = max(time_freq, -MAXFREQ_SCALED);
                }
-               time_esterror = txc->esterror;
-           }
 
-           if (txc->modes & ADJ_TIMECONST) {   /* p. 24 */
-               if (txc->constant < 0) {        /* NTP v4 uses values > 6 */
-                   result = -EINVAL;
-                   goto leave;
+               if (txc->modes & ADJ_MAXERROR)
+                       time_maxerror = txc->maxerror;
+               if (txc->modes & ADJ_ESTERROR)
+                       time_esterror = txc->esterror;
+
+               if (txc->modes & ADJ_TIMECONST) {
+                       time_constant = txc->constant;
+                       if (!(time_status & STA_NANO))
+                               time_constant += 4;
+                       time_constant = min(time_constant, (long)MAXTC);
+                       time_constant = max(time_constant, 0l);
                }
-               time_constant = min(txc->constant + 4, (long)MAXTC);
-           }
 
-           if (txc->modes & ADJ_OFFSET) {      /* values checked earlier */
-               if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
-                   /* adjtime() is independent from ntp_adjtime() */
-                   time_adjust = txc->offset;
+               if (txc->modes & ADJ_TAI && txc->constant > 0)
+                       time_tai = txc->constant;
+
+               if (txc->modes & ADJ_OFFSET) {
+                       if (txc->modes == ADJ_OFFSET_SINGLESHOT)
+                               /* adjtime() is independent from ntp_adjtime() */
+                               time_adjust = txc->offset;
+                       else
+                               ntp_update_offset(txc->offset);
                }
-               else if (time_status & STA_PLL) {
-                   time_offset = txc->offset * NSEC_PER_USEC;
-
-                   /*
-                    * Scale the phase adjustment and
-                    * clamp to the operating range.
-                    */
-                   time_offset = min(time_offset, (s64)MAXPHASE * NSEC_PER_USEC);
-                   time_offset = max(time_offset, (s64)-MAXPHASE * NSEC_PER_USEC);
-
-                   /*
-                    * Select whether the frequency is to be controlled
-                    * and in which mode (PLL or FLL). Clamp to the operating
-                    * range. Ugly multiply/divide should be replaced someday.
-                    */
-
-                   if (time_status & STA_FREQHOLD || time_reftime == 0)
-                       time_reftime = xtime.tv_sec;
-                   mtemp = xtime.tv_sec - time_reftime;
-                   time_reftime = xtime.tv_sec;
-
-                   freq_adj = time_offset * mtemp;
-                   freq_adj = shift_right(freq_adj, time_constant * 2 +
-                                          (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
-                   if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
-                       temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
-                       if (time_offset < 0) {
-                           temp64 = -temp64;
-                           do_div(temp64, mtemp);
-                           freq_adj -= temp64;
-                       } else {
-                           do_div(temp64, mtemp);
-                           freq_adj += temp64;
-                       }
-                   }
-                   freq_adj += time_freq;
-                   freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
-                   time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
-                   time_offset = div_long_long_rem_signed(time_offset,
-                                                          NTP_INTERVAL_FREQ,
-                                                          &rem);
-                   time_offset <<= SHIFT_UPDATE;
-               } /* STA_PLL */
-           } /* txc->modes & ADJ_OFFSET */
-           if (txc->modes & ADJ_TICK)
-               tick_usec = txc->tick;
-
-           if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
-                   ntp_update_frequency();
-       } /* txc->modes */
-leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
+               if (txc->modes & ADJ_TICK)
+                       tick_usec = txc->tick;
+
+               if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
+                       ntp_update_frequency();
+       }
+
+       result = time_state;    /* mostly `TIME_OK' */
+       if (time_status & (STA_UNSYNC|STA_CLOCKERR))
                result = TIME_ERROR;
 
-       if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
+       if ((txc->modes == ADJ_OFFSET_SINGLESHOT) ||
+           (txc->modes == ADJ_OFFSET_SS_READ))
                txc->offset = save_adjust;
-       else
-               txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) *
-                               NTP_INTERVAL_FREQ / 1000;
-       txc->freq          = (time_freq / NSEC_PER_USEC) <<
-                               (SHIFT_USEC - SHIFT_NSEC);
+       else {
+               txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
+                                         TICK_LENGTH_SHIFT);
+               if (!(time_status & STA_NANO))
+                       txc->offset /= NSEC_PER_USEC;
+       }
+       txc->freq          = shift_right((s32)(time_freq >> PPM_SCALE_INV_SHIFT) *
+                                        (s64)PPM_SCALE_INV,
+                                        TICK_LENGTH_SHIFT);
        txc->maxerror      = time_maxerror;
        txc->esterror      = time_esterror;
        txc->status        = time_status;
        txc->constant      = time_constant;
        txc->precision     = 1;
-       txc->tolerance     = MAXFREQ;
+       txc->tolerance     = MAXFREQ_SCALED / PPM_SCALE;
        txc->tick          = tick_usec;
+       txc->tai           = time_tai;
 
        /* PPS is not implemented, so these are zero */
        txc->ppsfreq       = 0;
@@ -356,7 +395,22 @@ leave:     if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
        txc->errcnt        = 0;
        txc->stbcnt        = 0;
        write_sequnlock_irq(&xtime_lock);
-       do_gettimeofday(&txc->time);
-       notify_arch_cmos_timer();
-       return(result);
+
+       getnstimeofday(&ts);
+       txc->time.tv_sec = ts.tv_sec;
+       txc->time.tv_usec = ts.tv_nsec;
+       if (!(time_status & STA_NANO))
+               txc->time.tv_usec /= NSEC_PER_USEC;
+
+       notify_cmos_timer();
+
+       return result;
+}
+
+static int __init ntp_tick_adj_setup(char *str)
+{
+       ntp_tick_adj = simple_strtol(str, NULL, 0);
+       return 1;
 }
+
+__setup("ntp_tick_adj=", ntp_tick_adj_setup);