Commit 0077dc60 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by John Stultz
Browse files

timekeeping: Provide ktime_get_with_offset() 



Provide a helper function which lets us implement ktime_t based
interfaces for real, boot and tai clocks.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent a016a5bd

include/linux/timekeeping.h

+9 −0
Original line number Diff line number Diff line
@@ -98,7 +98,16 @@ extern void getboottime(struct timespec *ts); 
/*

 * ktime_t based interfaces

 */



enum tk_offsets {

	TK_OFFS_REAL,

	TK_OFFS_BOOT,

	TK_OFFS_TAI,

	TK_OFFS_MAX,

};



extern ktime_t ktime_get(void);

extern ktime_t ktime_get_with_offset(enum tk_offsets offs);

extern ktime_t ktime_get_real(void);

extern ktime_t ktime_get_boottime(void);

extern ktime_t ktime_get_monotonic_offset(void);

kernel/time/timekeeping.c

+27 −0
Original line number Diff line number Diff line
@@ -423,6 +423,33 @@ ktime_t ktime_get(void) 
}

EXPORT_SYMBOL_GPL(ktime_get);



static ktime_t *offsets[TK_OFFS_MAX] = {

	[TK_OFFS_REAL]	= &tk_core.timekeeper.offs_real,

	[TK_OFFS_BOOT]	= &tk_core.timekeeper.offs_boot,

	[TK_OFFS_TAI]	= &tk_core.timekeeper.offs_tai,

};



ktime_t ktime_get_with_offset(enum tk_offsets offs)

{

	struct timekeeper *tk = &tk_core.timekeeper;

	unsigned int seq;

	ktime_t base, *offset = offsets[offs];

	s64 nsecs;



	WARN_ON(timekeeping_suspended);



	do {

		seq = read_seqcount_begin(&tk_core.seq);

		base = ktime_add(tk->base_mono, *offset);

		nsecs = timekeeping_get_ns(tk);



	} while (read_seqcount_retry(&tk_core.seq, seq));



	return ktime_add_ns(base, nsecs);



}

EXPORT_SYMBOL_GPL(ktime_get_with_offset);



/**

 * ktime_get_ts64 - get the monotonic clock in timespec64 format

 * @ts:		pointer to timespec variable