2 * NTP state machine interfaces and logic.
4 * This code was mainly moved from kernel/timer.c and kernel/time.c
5 * Please see those files for relevant copyright info and historical
8 #include <linux/capability.h>
9 #include <linux/clocksource.h>
10 #include <linux/workqueue.h>
11 #include <linux/hrtimer.h>
12 #include <linux/jiffies.h>
13 #include <linux/math64.h>
14 #include <linux/timex.h>
15 #include <linux/time.h>
17 #include <linux/module.h>
18 #include <linux/rtc.h>
20 #include "tick-internal.h"
21 #include "ntp_internal.h"
24 * NTP timekeeping variables:
26 * Note: All of the NTP state is protected by the timekeeping locks.
30 /* USER_HZ period (usecs): */
31 unsigned long tick_usec = TICK_USEC;
33 /* SHIFTED_HZ period (nsecs): */
34 unsigned long tick_nsec;
36 static u64 tick_length;
37 static u64 tick_length_base;
39 #define MAX_TICKADJ 500LL /* usecs */
40 #define MAX_TICKADJ_SCALED \
41 (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
44 * phase-lock loop variables
48 * clock synchronization status
50 * (TIME_ERROR prevents overwriting the CMOS clock)
52 static int time_state = TIME_OK;
54 /* clock status bits: */
55 static int time_status = STA_UNSYNC;
57 /* time adjustment (nsecs): */
58 static s64 time_offset;
60 /* pll time constant: */
61 static long time_constant = 2;
63 /* maximum error (usecs): */
64 static long time_maxerror = NTP_PHASE_LIMIT;
66 /* estimated error (usecs): */
67 static long time_esterror = NTP_PHASE_LIMIT;
69 /* frequency offset (scaled nsecs/secs): */
72 /* time at last adjustment (secs): */
73 static long time_reftime;
75 static long time_adjust;
77 /* constant (boot-param configurable) NTP tick adjustment (upscaled) */
78 static s64 ntp_tick_adj;
83 * The following variables are used when a pulse-per-second (PPS) signal
84 * is available. They establish the engineering parameters of the clock
85 * discipline loop when controlled by the PPS signal.
87 #define PPS_VALID 10 /* PPS signal watchdog max (s) */
88 #define PPS_POPCORN 4 /* popcorn spike threshold (shift) */
89 #define PPS_INTMIN 2 /* min freq interval (s) (shift) */
90 #define PPS_INTMAX 8 /* max freq interval (s) (shift) */
91 #define PPS_INTCOUNT 4 /* number of consecutive good intervals to
92 increase pps_shift or consecutive bad
93 intervals to decrease it */
94 #define PPS_MAXWANDER 100000 /* max PPS freq wander (ns/s) */
96 static int pps_valid; /* signal watchdog counter */
97 static long pps_tf[3]; /* phase median filter */
98 static long pps_jitter; /* current jitter (ns) */
99 static struct timespec pps_fbase; /* beginning of the last freq interval */
100 static int pps_shift; /* current interval duration (s) (shift) */
101 static int pps_intcnt; /* interval counter */
102 static s64 pps_freq; /* frequency offset (scaled ns/s) */
103 static long pps_stabil; /* current stability (scaled ns/s) */
106 * PPS signal quality monitors
108 static long pps_calcnt; /* calibration intervals */
109 static long pps_jitcnt; /* jitter limit exceeded */
110 static long pps_stbcnt; /* stability limit exceeded */
111 static long pps_errcnt; /* calibration errors */
114 /* PPS kernel consumer compensates the whole phase error immediately.
115 * Otherwise, reduce the offset by a fixed factor times the time constant.
117 static inline s64 ntp_offset_chunk(s64 offset)
119 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
122 return shift_right(offset, SHIFT_PLL + time_constant);
125 static inline void pps_reset_freq_interval(void)
127 /* the PPS calibration interval may end
128 surprisingly early */
129 pps_shift = PPS_INTMIN;
134 * pps_clear - Clears the PPS state variables
136 static inline void pps_clear(void)
138 pps_reset_freq_interval();
142 pps_fbase.tv_sec = pps_fbase.tv_nsec = 0;
146 /* Decrease pps_valid to indicate that another second has passed since
147 * the last PPS signal. When it reaches 0, indicate that PPS signal is
150 static inline void pps_dec_valid(void)
155 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
156 STA_PPSWANDER | STA_PPSERROR);
161 static inline void pps_set_freq(s64 freq)
166 static inline int is_error_status(int status)
168 return (status & (STA_UNSYNC|STA_CLOCKERR))
169 /* PPS signal lost when either PPS time or
170 * PPS frequency synchronization requested
172 || ((status & (STA_PPSFREQ|STA_PPSTIME))
173 && !(status & STA_PPSSIGNAL))
174 /* PPS jitter exceeded when
175 * PPS time synchronization requested */
176 || ((status & (STA_PPSTIME|STA_PPSJITTER))
177 == (STA_PPSTIME|STA_PPSJITTER))
178 /* PPS wander exceeded or calibration error when
179 * PPS frequency synchronization requested
181 || ((status & STA_PPSFREQ)
182 && (status & (STA_PPSWANDER|STA_PPSERROR)));
185 static inline void pps_fill_timex(struct timex *txc)
187 txc->ppsfreq = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) *
188 PPM_SCALE_INV, NTP_SCALE_SHIFT);
189 txc->jitter = pps_jitter;
190 if (!(time_status & STA_NANO))
191 txc->jitter /= NSEC_PER_USEC;
192 txc->shift = pps_shift;
193 txc->stabil = pps_stabil;
194 txc->jitcnt = pps_jitcnt;
195 txc->calcnt = pps_calcnt;
196 txc->errcnt = pps_errcnt;
197 txc->stbcnt = pps_stbcnt;
200 #else /* !CONFIG_NTP_PPS */
202 static inline s64 ntp_offset_chunk(s64 offset)
204 return shift_right(offset, SHIFT_PLL + time_constant);
207 static inline void pps_reset_freq_interval(void) {}
208 static inline void pps_clear(void) {}
209 static inline void pps_dec_valid(void) {}
210 static inline void pps_set_freq(s64 freq) {}
212 static inline int is_error_status(int status)
214 return status & (STA_UNSYNC|STA_CLOCKERR);
217 static inline void pps_fill_timex(struct timex *txc)
219 /* PPS is not implemented, so these are zero */
230 #endif /* CONFIG_NTP_PPS */
234 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
237 static inline int ntp_synced(void)
239 return !(time_status & STA_UNSYNC);
248 * Update (tick_length, tick_length_base, tick_nsec), based
249 * on (tick_usec, ntp_tick_adj, time_freq):
251 static void ntp_update_frequency(void)
256 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
259 second_length += ntp_tick_adj;
260 second_length += time_freq;
262 tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
263 new_base = div_u64(second_length, NTP_INTERVAL_FREQ);
266 * Don't wait for the next second_overflow, apply
267 * the change to the tick length immediately:
269 tick_length += new_base - tick_length_base;
270 tick_length_base = new_base;
273 static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
275 time_status &= ~STA_MODE;
280 if (!(time_status & STA_FLL) && (secs <= MAXSEC))
283 time_status |= STA_MODE;
285 return div64_long(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
288 static void ntp_update_offset(long offset)
294 if (!(time_status & STA_PLL))
297 if (!(time_status & STA_NANO))
298 offset *= NSEC_PER_USEC;
301 * Scale the phase adjustment and
302 * clamp to the operating range.
304 offset = min(offset, MAXPHASE);
305 offset = max(offset, -MAXPHASE);
308 * Select how the frequency is to be controlled
309 * and in which mode (PLL or FLL).
311 secs = get_seconds() - time_reftime;
312 if (unlikely(time_status & STA_FREQHOLD))
315 time_reftime = get_seconds();
318 freq_adj = ntp_update_offset_fll(offset64, secs);
321 * Clamp update interval to reduce PLL gain with low
322 * sampling rate (e.g. intermittent network connection)
323 * to avoid instability.
325 if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
326 secs = 1 << (SHIFT_PLL + 1 + time_constant);
328 freq_adj += (offset64 * secs) <<
329 (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
331 freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED);
333 time_freq = max(freq_adj, -MAXFREQ_SCALED);
335 time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
339 * ntp_clear - Clears the NTP state variables
343 time_adjust = 0; /* stop active adjtime() */
344 time_status |= STA_UNSYNC;
345 time_maxerror = NTP_PHASE_LIMIT;
346 time_esterror = NTP_PHASE_LIMIT;
348 ntp_update_frequency();
350 tick_length = tick_length_base;
353 /* Clear PPS state variables */
358 u64 ntp_tick_length(void)
365 * this routine handles the overflow of the microsecond field
367 * The tricky bits of code to handle the accurate clock support
368 * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
369 * They were originally developed for SUN and DEC kernels.
370 * All the kudos should go to Dave for this stuff.
372 * Also handles leap second processing, and returns leap offset
374 int second_overflow(unsigned long secs)
380 * Leap second processing. If in leap-insert state at the end of the
381 * day, the system clock is set back one second; if in leap-delete
382 * state, the system clock is set ahead one second.
384 switch (time_state) {
386 if (time_status & STA_INS)
387 time_state = TIME_INS;
388 else if (time_status & STA_DEL)
389 time_state = TIME_DEL;
392 if (!(time_status & STA_INS))
393 time_state = TIME_OK;
394 else if (secs % 86400 == 0) {
396 time_state = TIME_OOP;
398 "Clock: inserting leap second 23:59:60 UTC\n");
402 if (!(time_status & STA_DEL))
403 time_state = TIME_OK;
404 else if ((secs + 1) % 86400 == 0) {
406 time_state = TIME_WAIT;
408 "Clock: deleting leap second 23:59:59 UTC\n");
412 time_state = TIME_WAIT;
416 if (!(time_status & (STA_INS | STA_DEL)))
417 time_state = TIME_OK;
422 /* Bump the maxerror field */
423 time_maxerror += MAXFREQ / NSEC_PER_USEC;
424 if (time_maxerror > NTP_PHASE_LIMIT) {
425 time_maxerror = NTP_PHASE_LIMIT;
426 time_status |= STA_UNSYNC;
429 /* Compute the phase adjustment for the next second */
430 tick_length = tick_length_base;
432 delta = ntp_offset_chunk(time_offset);
433 time_offset -= delta;
434 tick_length += delta;
436 /* Check PPS signal */
442 if (time_adjust > MAX_TICKADJ) {
443 time_adjust -= MAX_TICKADJ;
444 tick_length += MAX_TICKADJ_SCALED;
448 if (time_adjust < -MAX_TICKADJ) {
449 time_adjust += MAX_TICKADJ;
450 tick_length -= MAX_TICKADJ_SCALED;
454 tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
462 #if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC)
463 static void sync_cmos_clock(struct work_struct *work);
465 static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
467 static void sync_cmos_clock(struct work_struct *work)
469 struct timespec now, next;
473 * If we have an externally synchronized Linux clock, then update
474 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
475 * called as close as possible to 500 ms before the new second starts.
476 * This code is run on a timer. If the clock is set, that timer
477 * may not expire at the correct time. Thus, we adjust...
478 * We want the clock to be within a couple of ticks from the target.
482 * Not synced, exit, do not restart a timer (if one is
483 * running, let it run out).
488 getnstimeofday(&now);
489 if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec * 5) {
490 struct timespec adjust = now;
493 if (persistent_clock_is_local)
494 adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
495 #ifdef CONFIG_GENERIC_CMOS_UPDATE
496 fail = update_persistent_clock(adjust);
498 #ifdef CONFIG_RTC_SYSTOHC
500 fail = rtc_set_ntp_time(adjust);
504 next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
505 if (next.tv_nsec <= 0)
506 next.tv_nsec += NSEC_PER_SEC;
508 if (!fail || fail == -ENODEV)
513 if (next.tv_nsec >= NSEC_PER_SEC) {
515 next.tv_nsec -= NSEC_PER_SEC;
517 queue_delayed_work(system_power_efficient_wq,
518 &sync_cmos_work, timespec_to_jiffies(&next));
521 void ntp_notify_cmos_timer(void)
523 queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
527 void ntp_notify_cmos_timer(void) { }
532 * Propagate a new txc->status value into the NTP state:
534 static inline void process_adj_status(struct timex *txc, struct timespec *ts)
536 if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
537 time_state = TIME_OK;
538 time_status = STA_UNSYNC;
539 /* restart PPS frequency calibration */
540 pps_reset_freq_interval();
544 * If we turn on PLL adjustments then reset the
545 * reference time to current time.
547 if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
548 time_reftime = get_seconds();
550 /* only set allowed bits */
551 time_status &= STA_RONLY;
552 time_status |= txc->status & ~STA_RONLY;
556 static inline void process_adjtimex_modes(struct timex *txc,
560 if (txc->modes & ADJ_STATUS)
561 process_adj_status(txc, ts);
563 if (txc->modes & ADJ_NANO)
564 time_status |= STA_NANO;
566 if (txc->modes & ADJ_MICRO)
567 time_status &= ~STA_NANO;
569 if (txc->modes & ADJ_FREQUENCY) {
570 time_freq = txc->freq * PPM_SCALE;
571 time_freq = min(time_freq, MAXFREQ_SCALED);
572 time_freq = max(time_freq, -MAXFREQ_SCALED);
573 /* update pps_freq */
574 pps_set_freq(time_freq);
577 if (txc->modes & ADJ_MAXERROR)
578 time_maxerror = txc->maxerror;
580 if (txc->modes & ADJ_ESTERROR)
581 time_esterror = txc->esterror;
583 if (txc->modes & ADJ_TIMECONST) {
584 time_constant = txc->constant;
585 if (!(time_status & STA_NANO))
587 time_constant = min(time_constant, (long)MAXTC);
588 time_constant = max(time_constant, 0l);
591 if (txc->modes & ADJ_TAI && txc->constant > 0)
592 *time_tai = txc->constant;
594 if (txc->modes & ADJ_OFFSET)
595 ntp_update_offset(txc->offset);
597 if (txc->modes & ADJ_TICK)
598 tick_usec = txc->tick;
600 if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
601 ntp_update_frequency();
607 * ntp_validate_timex - Ensures the timex is ok for use in do_adjtimex
609 int ntp_validate_timex(struct timex *txc)
611 if (txc->modes & ADJ_ADJTIME) {
612 /* singleshot must not be used with any other mode bits */
613 if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
615 if (!(txc->modes & ADJ_OFFSET_READONLY) &&
616 !capable(CAP_SYS_TIME))
619 /* In order to modify anything, you gotta be super-user! */
620 if (txc->modes && !capable(CAP_SYS_TIME))
623 * if the quartz is off by more than 10% then
624 * something is VERY wrong!
626 if (txc->modes & ADJ_TICK &&
627 (txc->tick < 900000/USER_HZ ||
628 txc->tick > 1100000/USER_HZ))
632 if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME)))
640 * adjtimex mainly allows reading (and writing, if superuser) of
641 * kernel time-keeping variables. used by xntpd.
643 int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai)
647 if (txc->modes & ADJ_ADJTIME) {
648 long save_adjust = time_adjust;
650 if (!(txc->modes & ADJ_OFFSET_READONLY)) {
651 /* adjtime() is independent from ntp_adjtime() */
652 time_adjust = txc->offset;
653 ntp_update_frequency();
655 txc->offset = save_adjust;
658 /* If there are input parameters, then process them: */
660 process_adjtimex_modes(txc, ts, time_tai);
662 txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
664 if (!(time_status & STA_NANO))
665 txc->offset /= NSEC_PER_USEC;
668 result = time_state; /* mostly `TIME_OK' */
669 /* check for errors */
670 if (is_error_status(time_status))
673 txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
674 PPM_SCALE_INV, NTP_SCALE_SHIFT);
675 txc->maxerror = time_maxerror;
676 txc->esterror = time_esterror;
677 txc->status = time_status;
678 txc->constant = time_constant;
680 txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
681 txc->tick = tick_usec;
682 txc->tai = *time_tai;
684 /* fill PPS status fields */
687 txc->time.tv_sec = ts->tv_sec;
688 txc->time.tv_usec = ts->tv_nsec;
689 if (!(time_status & STA_NANO))
690 txc->time.tv_usec /= NSEC_PER_USEC;
695 #ifdef CONFIG_NTP_PPS
697 /* actually struct pps_normtime is good old struct timespec, but it is
698 * semantically different (and it is the reason why it was invented):
699 * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ]
700 * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */
701 struct pps_normtime {
702 __kernel_time_t sec; /* seconds */
703 long nsec; /* nanoseconds */
706 /* normalize the timestamp so that nsec is in the
707 ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */
708 static inline struct pps_normtime pps_normalize_ts(struct timespec ts)
710 struct pps_normtime norm = {
715 if (norm.nsec > (NSEC_PER_SEC >> 1)) {
716 norm.nsec -= NSEC_PER_SEC;
723 /* get current phase correction and jitter */
724 static inline long pps_phase_filter_get(long *jitter)
726 *jitter = pps_tf[0] - pps_tf[1];
730 /* TODO: test various filters */
734 /* add the sample to the phase filter */
735 static inline void pps_phase_filter_add(long err)
737 pps_tf[2] = pps_tf[1];
738 pps_tf[1] = pps_tf[0];
742 /* decrease frequency calibration interval length.
743 * It is halved after four consecutive unstable intervals.
745 static inline void pps_dec_freq_interval(void)
747 if (--pps_intcnt <= -PPS_INTCOUNT) {
748 pps_intcnt = -PPS_INTCOUNT;
749 if (pps_shift > PPS_INTMIN) {
756 /* increase frequency calibration interval length.
757 * It is doubled after four consecutive stable intervals.
759 static inline void pps_inc_freq_interval(void)
761 if (++pps_intcnt >= PPS_INTCOUNT) {
762 pps_intcnt = PPS_INTCOUNT;
763 if (pps_shift < PPS_INTMAX) {
770 /* update clock frequency based on MONOTONIC_RAW clock PPS signal
773 * At the end of the calibration interval the difference between the
774 * first and last MONOTONIC_RAW clock timestamps divided by the length
775 * of the interval becomes the frequency update. If the interval was
776 * too long, the data are discarded.
777 * Returns the difference between old and new frequency values.
779 static long hardpps_update_freq(struct pps_normtime freq_norm)
781 long delta, delta_mod;
784 /* check if the frequency interval was too long */
785 if (freq_norm.sec > (2 << pps_shift)) {
786 time_status |= STA_PPSERROR;
788 pps_dec_freq_interval();
789 pr_err("hardpps: PPSERROR: interval too long - %ld s\n",
794 /* here the raw frequency offset and wander (stability) is
795 * calculated. If the wander is less than the wander threshold
796 * the interval is increased; otherwise it is decreased.
798 ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT,
800 delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT);
802 if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) {
803 pr_warning("hardpps: PPSWANDER: change=%ld\n", delta);
804 time_status |= STA_PPSWANDER;
806 pps_dec_freq_interval();
807 } else { /* good sample */
808 pps_inc_freq_interval();
811 /* the stability metric is calculated as the average of recent
812 * frequency changes, but is used only for performance
817 delta_mod = -delta_mod;
818 pps_stabil += (div_s64(((s64)delta_mod) <<
819 (NTP_SCALE_SHIFT - SHIFT_USEC),
820 NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN;
822 /* if enabled, the system clock frequency is updated */
823 if ((time_status & STA_PPSFREQ) != 0 &&
824 (time_status & STA_FREQHOLD) == 0) {
825 time_freq = pps_freq;
826 ntp_update_frequency();
832 /* correct REALTIME clock phase error against PPS signal */
833 static void hardpps_update_phase(long error)
835 long correction = -error;
838 /* add the sample to the median filter */
839 pps_phase_filter_add(correction);
840 correction = pps_phase_filter_get(&jitter);
842 /* Nominal jitter is due to PPS signal noise. If it exceeds the
843 * threshold, the sample is discarded; otherwise, if so enabled,
844 * the time offset is updated.
846 if (jitter > (pps_jitter << PPS_POPCORN)) {
847 pr_warning("hardpps: PPSJITTER: jitter=%ld, limit=%ld\n",
848 jitter, (pps_jitter << PPS_POPCORN));
849 time_status |= STA_PPSJITTER;
851 } else if (time_status & STA_PPSTIME) {
852 /* correct the time using the phase offset */
853 time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT,
855 /* cancel running adjtime() */
859 pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN;
863 * __hardpps() - discipline CPU clock oscillator to external PPS signal
865 * This routine is called at each PPS signal arrival in order to
866 * discipline the CPU clock oscillator to the PPS signal. It takes two
867 * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former
868 * is used to correct clock phase error and the latter is used to
869 * correct the frequency.
871 * This code is based on David Mills's reference nanokernel
872 * implementation. It was mostly rewritten but keeps the same idea.
874 void __hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
876 struct pps_normtime pts_norm, freq_norm;
878 pts_norm = pps_normalize_ts(*phase_ts);
880 /* clear the error bits, they will be set again if needed */
881 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
883 /* indicate signal presence */
884 time_status |= STA_PPSSIGNAL;
885 pps_valid = PPS_VALID;
887 /* when called for the first time,
888 * just start the frequency interval */
889 if (unlikely(pps_fbase.tv_sec == 0)) {
894 /* ok, now we have a base for frequency calculation */
895 freq_norm = pps_normalize_ts(timespec_sub(*raw_ts, pps_fbase));
897 /* check that the signal is in the range
898 * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */
899 if ((freq_norm.sec == 0) ||
900 (freq_norm.nsec > MAXFREQ * freq_norm.sec) ||
901 (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) {
902 time_status |= STA_PPSJITTER;
903 /* restart the frequency calibration interval */
905 pr_err("hardpps: PPSJITTER: bad pulse\n");
911 /* check if the current frequency interval is finished */
912 if (freq_norm.sec >= (1 << pps_shift)) {
914 /* restart the frequency calibration interval */
916 hardpps_update_freq(freq_norm);
919 hardpps_update_phase(pts_norm.nsec);
922 #endif /* CONFIG_NTP_PPS */
924 static int __init ntp_tick_adj_setup(char *str)
926 int rc = kstrtol(str, 0, (long *)&ntp_tick_adj);
930 ntp_tick_adj <<= NTP_SCALE_SHIFT;
935 __setup("ntp_tick_adj=", ntp_tick_adj_setup);
937 void __init ntp_init(void)