/*
 * mtime, short for monotonic time, starts from 0 when system starts up.
 * It is a 64-bit variable counted in units of nanoseconds, which gives
 * ~584 years of time for the unsigned version.
 *
 * mtime is implemented on top of tock.  By reading tock values regularly
 * mtime can be advanced accordingly.
 *
 * mtime can be adjusted to achieve high accuracy, either by exploring
 * intrinsic tock skewing or through external time source.  Any adjustment to
 * mtime will preserve the monotonicity, i.e., no two consecutive
 * mtime readings will show backward movement in mtime.
 *
 * mtimers are timers that expire in mtime.  The callback of mtimer
 * when it expires is in interrupt context.
 */

#ifndef _LINUX_MTIME_H
#define _LINUX_MTIME_H

#include <linux/types.h>
#include <linux/tock.h>

/*
 * latch and return current mtime.
 */
u64 mtime_latch(void);

/*
 * return the last latched mtime.
 */
u64 mtime_get(void);

/*
 * Adjust mtime with the specified offset.  Return the amount of time
 * actually adjusted.
 */
s64 mtime_adjust(s64 delta);

/*
 * mtimers
 */
void mtimer_add(struct mtimer_struct *);
void mtimer_del(struct mtimer_struct *);
void mtimer_mod(struct mtimer_struct *, u64 new_expire);

#endif