Files
android_kernel_xiaomi_sm8450/include/linux/timekeeping.h
Heena Sirwani 9e3680b175 timekeeping: Provide fast accessor to the seconds part of CLOCK_MONOTONIC
This is the counterpart to get_seconds() based on CLOCK_MONOTONIC. The
use case for this interface are kernel internal coarse grained
timestamps which do neither require the nanoseconds fraction of
current time nor the CLOCK_REALTIME properties. Such timestamps can
currently only retrieved by calling ktime_get_ts64() and using the
tv_sec field of the returned timespec64. That's inefficient as it
involves the read of the clocksource, math operations and must be
protected by the timekeeper sequence counter.

To avoid the sequence counter protection we restrict the return value
to unsigned 32bit on 32bit machines. This covers ~136 years of uptime
and therefor an overflow is not expected to hit anytime soon.

To avoid math in the function we calculate the current seconds portion
of CLOCK_MONOTONIC when the timekeeper gets updated in
tk_update_ktime_data() similar to the CLOCK_REALTIME counterpart
xtime_sec.

[ tglx: Massaged changelog, simplified and commented the update
  	function, added docbook comment ]

Signed-off-by: Heena Sirwani <heenasirwani@gmail.com>
Reviewed-by: Arnd Bergman <arnd@arndb.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: opw-kernel@googlegroups.com
Link: http://lkml.kernel.org/r/da0b63f4bdf3478909f92becb35861197da3a905.1414578445.git.heenasirwani@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-29 15:15:40 +01:00

211 lines
4.3 KiB
C

#ifndef _LINUX_TIMEKEEPING_H
#define _LINUX_TIMEKEEPING_H
/* Included from linux/ktime.h */
void timekeeping_init(void);
extern int timekeeping_suspended;
/*
* Get and set timeofday
*/
extern void do_gettimeofday(struct timeval *tv);
extern int do_settimeofday(const struct timespec *tv);
extern int do_sys_settimeofday(const struct timespec *tv,
const struct timezone *tz);
/*
* Kernel time accessors
*/
unsigned long get_seconds(void);
struct timespec current_kernel_time(void);
/* does not take xtime_lock */
struct timespec __current_kernel_time(void);
/*
* timespec based interfaces
*/
struct timespec get_monotonic_coarse(void);
extern void getrawmonotonic(struct timespec *ts);
extern void ktime_get_ts64(struct timespec64 *ts);
extern time64_t ktime_get_seconds(void);
extern int __getnstimeofday64(struct timespec64 *tv);
extern void getnstimeofday64(struct timespec64 *tv);
#if BITS_PER_LONG == 64
static inline int __getnstimeofday(struct timespec *ts)
{
return __getnstimeofday64(ts);
}
static inline void getnstimeofday(struct timespec *ts)
{
getnstimeofday64(ts);
}
static inline void ktime_get_ts(struct timespec *ts)
{
ktime_get_ts64(ts);
}
static inline void ktime_get_real_ts(struct timespec *ts)
{
getnstimeofday64(ts);
}
#else
static inline int __getnstimeofday(struct timespec *ts)
{
struct timespec64 ts64;
int ret = __getnstimeofday64(&ts64);
*ts = timespec64_to_timespec(ts64);
return ret;
}
static inline void getnstimeofday(struct timespec *ts)
{
struct timespec64 ts64;
getnstimeofday64(&ts64);
*ts = timespec64_to_timespec(ts64);
}
static inline void ktime_get_ts(struct timespec *ts)
{
struct timespec64 ts64;
ktime_get_ts64(&ts64);
*ts = timespec64_to_timespec(ts64);
}
static inline void ktime_get_real_ts(struct timespec *ts)
{
struct timespec64 ts64;
getnstimeofday64(&ts64);
*ts = timespec64_to_timespec(ts64);
}
#endif
extern void getboottime(struct timespec *ts);
#define do_posix_clock_monotonic_gettime(ts) ktime_get_ts(ts)
#define ktime_get_real_ts64(ts) getnstimeofday64(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_mono_to_any(ktime_t tmono, enum tk_offsets offs);
extern ktime_t ktime_get_raw(void);
/**
* ktime_get_real - get the real (wall-) time in ktime_t format
*/
static inline ktime_t ktime_get_real(void)
{
return ktime_get_with_offset(TK_OFFS_REAL);
}
/**
* ktime_get_boottime - Returns monotonic time since boot in ktime_t format
*
* This is similar to CLOCK_MONTONIC/ktime_get, but also includes the
* time spent in suspend.
*/
static inline ktime_t ktime_get_boottime(void)
{
return ktime_get_with_offset(TK_OFFS_BOOT);
}
/**
* ktime_get_clocktai - Returns the TAI time of day in ktime_t format
*/
static inline ktime_t ktime_get_clocktai(void)
{
return ktime_get_with_offset(TK_OFFS_TAI);
}
/**
* ktime_mono_to_real - Convert monotonic time to clock realtime
*/
static inline ktime_t ktime_mono_to_real(ktime_t mono)
{
return ktime_mono_to_any(mono, TK_OFFS_REAL);
}
static inline u64 ktime_get_ns(void)
{
return ktime_to_ns(ktime_get());
}
static inline u64 ktime_get_real_ns(void)
{
return ktime_to_ns(ktime_get_real());
}
static inline u64 ktime_get_boot_ns(void)
{
return ktime_to_ns(ktime_get_boottime());
}
static inline u64 ktime_get_raw_ns(void)
{
return ktime_to_ns(ktime_get_raw());
}
extern u64 ktime_get_mono_fast_ns(void);
/*
* Timespec interfaces utilizing the ktime based ones
*/
static inline void get_monotonic_boottime(struct timespec *ts)
{
*ts = ktime_to_timespec(ktime_get_boottime());
}
static inline void timekeeping_clocktai(struct timespec *ts)
{
*ts = ktime_to_timespec(ktime_get_clocktai());
}
/*
* RTC specific
*/
extern void timekeeping_inject_sleeptime(struct timespec *delta);
/*
* PPS accessor
*/
extern void getnstime_raw_and_real(struct timespec *ts_raw,
struct timespec *ts_real);
/*
* Persistent clock related interfaces
*/
extern bool persistent_clock_exist;
extern int persistent_clock_is_local;
static inline bool has_persistent_clock(void)
{
return persistent_clock_exist;
}
extern void read_persistent_clock(struct timespec *ts);
extern void read_boot_clock(struct timespec *ts);
extern int update_persistent_clock(struct timespec now);
#endif