Commit e2c18e49 authored by Alexander Gordeev's avatar Alexander Gordeev Committed by Linus Torvalds
Browse files

pps: capture MONOTONIC_RAW timestamps as well 



MONOTONIC_RAW clock timestamps are ideally suited for frequency
calculation and also fit well into the original NTP hardpps design.  Now
phase and frequency can be adjusted separately: the former based on
REALTIME clock and the latter based on MONOTONIC_RAW clock.

A new function getnstime_raw_and_real is added to timekeeping subsystem to
capture both timestamps at the same time and atomically.

Signed-off-by: default avatarAlexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: default avatarJohn Stultz <johnstul@us.ibm.com>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 025b40ab

include/linux/pps_kernel.h

+14 −0
Original line number Diff line number Diff line
@@ -47,6 +47,9 @@ struct pps_source_info { 
};



struct pps_event_time {

#ifdef CONFIG_NTP_PPS

	struct timespec ts_raw;

#endif /* CONFIG_NTP_PPS */

	struct timespec ts_real;

};
@@ -97,10 +100,21 @@ static inline void timespec_to_pps_ktime(struct pps_ktime *kt, 
	kt->nsec = ts.tv_nsec;

}



#ifdef CONFIG_NTP_PPS



static inline void pps_get_ts(struct pps_event_time *ts)

{

	getnstime_raw_and_real(&ts->ts_raw, &ts->ts_real);

}



#else /* CONFIG_NTP_PPS */



static inline void pps_get_ts(struct pps_event_time *ts)

{

	getnstimeofday(&ts->ts_real);

}



#endif /* CONFIG_NTP_PPS */



#endif /* LINUX_PPS_KERNEL_H */

include/linux/time.h

+2 −0
Original line number Diff line number Diff line
@@ -158,6 +158,8 @@ extern unsigned int alarm_setitimer(unsigned int seconds); 
extern int do_getitimer(int which, struct itimerval *value);

extern void getnstimeofday(struct timespec *tv);

extern void getrawmonotonic(struct timespec *ts);

extern void getnstime_raw_and_real(struct timespec *ts_raw,

		struct timespec *ts_real);

extern void getboottime(struct timespec *ts);

extern void monotonic_to_bootbased(struct timespec *ts);

kernel/time/timekeeping.c

+43 −0
Original line number Diff line number Diff line
@@ -288,6 +288,49 @@ void ktime_get_ts(struct timespec *ts) 
}

EXPORT_SYMBOL_GPL(ktime_get_ts);



#ifdef CONFIG_NTP_PPS



/**

 * getnstime_raw_and_real - get day and raw monotonic time in timespec format

 * @ts_raw:	pointer to the timespec to be set to raw monotonic time

 * @ts_real:	pointer to the timespec to be set to the time of day

 *

 * This function reads both the time of day and raw monotonic time at the

 * same time atomically and stores the resulting timestamps in timespec

 * format.

 */

void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)

{

	unsigned long seq;

	s64 nsecs_raw, nsecs_real;



	WARN_ON_ONCE(timekeeping_suspended);



	do {

		u32 arch_offset;



		seq = read_seqbegin(&xtime_lock);



		*ts_raw = raw_time;

		*ts_real = xtime;



		nsecs_raw = timekeeping_get_ns_raw();

		nsecs_real = timekeeping_get_ns();



		/* If arch requires, add in gettimeoffset() */

		arch_offset = arch_gettimeoffset();

		nsecs_raw += arch_offset;

		nsecs_real += arch_offset;



	} while (read_seqretry(&xtime_lock, seq));



	timespec_add_ns(ts_raw, nsecs_raw);

	timespec_add_ns(ts_real, nsecs_real);

}

EXPORT_SYMBOL(getnstime_raw_and_real);



#endif /* CONFIG_NTP_PPS */



/**

 * do_gettimeofday - Returns the time of day in a timeval

 * @tv:		pointer to the timeval to be set

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