19 #include "tick-internal.h"
41  * phase-lock loop variables
45  * clock synchronization status
47  * (TIME_ERROR prevents overwriting the CMOS clock)
51 /* clock status bits:							*/
77 /* constant (boot-param configurable) NTP tick adjustment (upscaled)	*/
83  * The following variables are used when a pulse-per-second (PPS) signal
84  * is available. They establish the engineering parameters of the clock
115  * Otherwise, reduce the offset by a fixed factor times the time constant.
134  * pps_clear - Clears the PPS state variables
157 		pps_valid--;  in pps_dec_valid()
191 	txc->ppsfreq	   = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) *  in pps_fill_timex()
193 	txc->jitter	   = pps_jitter;  in pps_fill_timex()
195 		txc->jitter /= NSEC_PER_USEC;  in pps_fill_timex()
196 	txc->shift	   = pps_shift;  in pps_fill_timex()
197 	txc->stabil	   = pps_stabil;  in pps_fill_timex()
198 	txc->jitcnt	   = pps_jitcnt;  in pps_fill_timex()
199 	txc->calcnt	   = pps_calcnt;  in pps_fill_timex()
200 	txc->errcnt	   = pps_errcnt;  in pps_fill_timex()
201 	txc->stbcnt	   = pps_stbcnt;  in pps_fill_timex()
224 	txc->ppsfreq	   = 0;  in pps_fill_timex()
225 	txc->jitter	   = 0;  in pps_fill_timex()
226 	txc->shift	   = 0;  in pps_fill_timex()
227 	txc->stabil	   = 0;  in pps_fill_timex()
228 	txc->jitcnt	   = 0;  in pps_fill_timex()
229 	txc->calcnt	   = 0;  in pps_fill_timex()
230 	txc->errcnt	   = 0;  in pps_fill_timex()
231 	txc->stbcnt	   = 0;  in pps_fill_timex()
262 	tick_length		+= new_base - tick_length_base;  in ntp_update_frequency()
278 	return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);  in ntp_update_offset_fll()
298 	offset = max(offset, -MAXPHASE);  in ntp_update_offset()
304 	secs = get_seconds() - time_reftime;  in ntp_update_offset()
322 			(NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));  in ntp_update_offset()
326 	time_freq   = max(freq_adj, -MAXFREQ_SCALED);  in ntp_update_offset()
332  * ntp_clear - Clears the NTP state variables
353  * Leap second processing. If in leap-insert state at the end of the
354  * day, the system clock is set back one second; if in leap-delete
355  * state, the system clock is set ahead one second.
367 		timekeeping_leap_insert(-1);  in ntp_leap_second()
370 			"Clock: inserting leap second 23:59:60 UTC\n");  in ntp_leap_second()
376 		time_tai--;  in ntp_leap_second()
379 			"Clock: deleting leap second 23:59:59 UTC\n");  in ntp_leap_second()
399  * The tricky bits of code to handle the accurate clock support
419 	time_offset	-= delta;  in second_overflow()
429 		time_adjust -= MAX_TICKADJ;  in second_overflow()
434 	if (time_adjust < -MAX_TICKADJ) {  in second_overflow()
436 		tick_length -= MAX_TICKADJ_SCALED;  in second_overflow()
447 /* Disable the cmos update - used by virtualization and embedded */
460 	 * If we have an externally synchronized Linux clock, then update  in sync_cmos_clock()
461 	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be  in sync_cmos_clock()
463 	 * This code is run on a timer.  If the clock is set, that timer  in sync_cmos_clock()
475 	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)  in sync_cmos_clock()
478 	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);  in sync_cmos_clock()
489 		next.tv_nsec -= NSEC_PER_SEC;  in sync_cmos_clock()
509 	long now = ts->tv_sec;  in ntp_start_leap_timer()
513 		now += 86400 - now % 86400;  in ntp_start_leap_timer()
521 		now += 86400 - (now + 1) % 86400;  in ntp_start_leap_timer()
527  * Propagate a new txc->status value into the NTP state:
531 	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {  in process_adj_status()
542 	if (!(time_status & STA_PLL) && (txc->status & STA_PLL))  in process_adj_status()
547 	time_status |= txc->status & ~STA_RONLY;  in process_adj_status()
572 	if (txc->modes & ADJ_STATUS)  in process_adjtimex_modes()
575 	if (txc->modes & ADJ_NANO)  in process_adjtimex_modes()
578 	if (txc->modes & ADJ_MICRO)  in process_adjtimex_modes()
581 	if (txc->modes & ADJ_FREQUENCY) {  in process_adjtimex_modes()
582 		time_freq = txc->freq * PPM_SCALE;  in process_adjtimex_modes()
584 		time_freq = max(time_freq, -MAXFREQ_SCALED);  in process_adjtimex_modes()
589 	if (txc->modes & ADJ_MAXERROR)  in process_adjtimex_modes()
590 		time_maxerror = txc->maxerror;  in process_adjtimex_modes()
592 	if (txc->modes & ADJ_ESTERROR)  in process_adjtimex_modes()
593 		time_esterror = txc->esterror;  in process_adjtimex_modes()
595 	if (txc->modes & ADJ_TIMECONST) {  in process_adjtimex_modes()
596 		time_constant = txc->constant;  in process_adjtimex_modes()
603 	if (txc->modes & ADJ_TAI && txc->constant > 0)  in process_adjtimex_modes()
604 		time_tai = txc->constant;  in process_adjtimex_modes()
606 	if (txc->modes & ADJ_OFFSET)  in process_adjtimex_modes()
607 		ntp_update_offset(txc->offset);  in process_adjtimex_modes()
609 	if (txc->modes & ADJ_TICK)  in process_adjtimex_modes()
610 		tick_usec = txc->tick;  in process_adjtimex_modes()
612 	if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))  in process_adjtimex_modes()
618  * kernel time-keeping variables. used by xntpd.
626 	if (txc->modes & ADJ_ADJTIME) {  in do_adjtimex()
628 		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))  in do_adjtimex()
629 			return -EINVAL;  in do_adjtimex()
630 		if (!(txc->modes & ADJ_OFFSET_READONLY) &&  in do_adjtimex()
632 			return -EPERM;  in do_adjtimex()
634 		/* In order to modify anything, you gotta be super-user! */  in do_adjtimex()
635 		 if (txc->modes && !capable(CAP_SYS_TIME))  in do_adjtimex()
636 			return -EPERM;  in do_adjtimex()
642 		if (txc->modes & ADJ_TICK &&  in do_adjtimex()
643 		    (txc->tick <  900000/USER_HZ ||  in do_adjtimex()
644 		     txc->tick > 1100000/USER_HZ))  in do_adjtimex()
645 			return -EINVAL;  in do_adjtimex()
647 		if (txc->modes & ADJ_STATUS && time_state != TIME_OK)  in do_adjtimex()
651 	if (txc->modes & ADJ_SETOFFSET) {  in do_adjtimex()
653 		delta.tv_sec  = txc->time.tv_sec;  in do_adjtimex()
654 		delta.tv_nsec = txc->time.tv_usec;  in do_adjtimex()
656 			return -EPERM;  in do_adjtimex()
657 		if (!(txc->modes & ADJ_NANO))  in do_adjtimex()
668 	if (txc->modes & ADJ_ADJTIME) {  in do_adjtimex()
671 		if (!(txc->modes & ADJ_OFFSET_READONLY)) {  in do_adjtimex()
673 			time_adjust = txc->offset;  in do_adjtimex()
676 		txc->offset = save_adjust;  in do_adjtimex()
680 		if (txc->modes)  in do_adjtimex()
683 		txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,  in do_adjtimex()
686 			txc->offset /= NSEC_PER_USEC;  in do_adjtimex()
694 	txc->freq	   = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *  in do_adjtimex()
696 	txc->maxerror	   = time_maxerror;  in do_adjtimex()
697 	txc->esterror	   = time_esterror;  in do_adjtimex()
698 	txc->status	   = time_status;  in do_adjtimex()
699 	txc->constant	   = time_constant;  in do_adjtimex()
700 	txc->precision	   = 1;  in do_adjtimex()
701 	txc->tolerance	   = MAXFREQ_SCALED / PPM_SCALE;  in do_adjtimex()
702 	txc->tick	   = tick_usec;  in do_adjtimex()
703 	txc->tai	   = time_tai;  in do_adjtimex()
710 	txc->time.tv_sec = ts.tv_sec;  in do_adjtimex()
711 	txc->time.tv_usec = ts.tv_nsec;  in do_adjtimex()
713 		txc->time.tv_usec /= NSEC_PER_USEC;  in do_adjtimex()
724  * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ]
732    ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */
741 		norm.nsec -= NSEC_PER_SEC;  in pps_normalize_ts()
751 	*jitter = pps_tf[0] - pps_tf[1];  in pps_phase_filter_get()
753 		*jitter = -*jitter;  in pps_phase_filter_get()
772 	if (--pps_intcnt <= -PPS_INTCOUNT) {  in pps_dec_freq_interval()
773 		pps_intcnt = -PPS_INTCOUNT;  in pps_dec_freq_interval()
775 			pps_shift--;  in pps_dec_freq_interval()
795 /* update clock frequency based on MONOTONIC_RAW clock PPS signal
799  * first and last MONOTONIC_RAW clock timestamps divided by the length
814 		pr_err("hardpps: PPSERROR: interval too long - %ld s\n",  in hardpps_update_freq()
823 	ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT,  in hardpps_update_freq()
825 	delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT);  in hardpps_update_freq()
827 	if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) {  in hardpps_update_freq()
842 		delta_mod = -delta_mod;  in hardpps_update_freq()
844 				(NTP_SCALE_SHIFT - SHIFT_USEC),  in hardpps_update_freq()
845 				NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN;  in hardpps_update_freq()
847 	/* if enabled, the system clock frequency is updated */  in hardpps_update_freq()
857 /* correct REALTIME clock phase error against PPS signal */
860 	long correction = -error;  in hardpps_update_phase()
884 	pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN;  in hardpps_update_phase()
888  * hardpps() - discipline CPU clock oscillator to external PPS signal
891  * discipline the CPU clock oscillator to the PPS signal. It takes two
892  * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former
893  * is used to correct clock phase error and the latter is used to
927 	 * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */  in hardpps()
930 			(freq_norm.nsec < -MAXFREQ * freq_norm.sec)) {  in hardpps()