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/* $OpenBSD: timetc.h,v 1.10 2019/10/26 21:16:38 cheloha Exp $ */
/*
* Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* If we meet some day, and you think this stuff is worth it, you
* can buy me a beer in return. Poul-Henning Kamp
*/
#ifndef _SYS_TIMETC_H_
#define _SYS_TIMETC_H_
#ifndef _KERNEL
#error "no user-serviceable parts inside"
#endif
#include <sys/queue.h>
/*-
* `struct timecounter' is the interface between the hardware which implements
* a timecounter and the MI code which uses this to keep track of time.
*
* A timecounter is a binary counter which has two properties:
* * it runs at a fixed, known frequency.
* * it has sufficient bits to not roll over in less than approximately
* max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta,
* for some indeterminate value of delta.)
*/
struct timecounter;
typedef u_int timecounter_get_t(struct timecounter *);
typedef void timecounter_pps_t(struct timecounter *);
/*
* Locks used to protect struct members in this file:
* I immutable after initialization
* t tc_lock
* w windup_mtx
*/
struct timecounter {
timecounter_get_t *tc_get_timecount; /* [I] */
/*
* This function reads the counter. It is not required to
* mask any unimplemented bits out, as long as they are
* constant.
*/
timecounter_pps_t *tc_poll_pps; /* [I] */
/*
* This function is optional. It will be called whenever the
* timecounter is rewound, and is intended to check for PPS
* events. Normal hardware does not need it but timecounters
* which latch PPS in hardware (like sys/pci/xrpu.c) do.
*/
u_int tc_counter_mask; /* [I] */
/* This mask should mask off any unimplemented bits. */
u_int64_t tc_frequency; /* [I] */
/* Frequency of the counter in Hz. */
char *tc_name; /* [I] */
/* Name of the timecounter. */
int tc_quality; /* [I] */
/*
* Used to determine if this timecounter is better than
* another timecounter higher means better. Negative
* means "only use at explicit request".
*/
void *tc_priv; /* [I] */
/* Pointer to the timecounter's private parts. */
SLIST_ENTRY(timecounter) tc_next; /* [I] */
/* Pointer to the next timecounter. */
int64_t tc_freq_adj; /* [tw] */
/* Current frequency adjustment. */
u_int64_t tc_precision; /* [I] */
/* Precision of the counter. Computed in tc_init(). */
};
struct rwlock;
extern struct rwlock tc_lock;
extern struct timecounter *timecounter;
u_int64_t tc_getfrequency(void);
u_int64_t tc_getprecision(void);
void tc_init(struct timecounter *tc);
void tc_setclock(const struct timespec *ts);
void tc_setrealtimeclock(const struct timespec *ts);
void tc_ticktock(void);
void inittimecounter(void);
int sysctl_tc(int *, u_int, void *, size_t *, void *, size_t);
void tc_adjfreq(int64_t *, int64_t *);
void tc_adjtime(int64_t *, int64_t *);
#endif /* !_SYS_TIMETC_H_ */
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