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/*-
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* $FreeBSD$
*/
#ifndef _SYS_TIMETC_H_
#define _SYS_TIMETC_H_
#ifndef _KERNEL
#error "no user-serviceable parts inside"
#endif
/*-
* `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 *);
struct timecounter {
timecounter_get_t *tc_get_timecount;
/*
* 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;
/*
* 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;
/* This mask should mask off any unimplemented bits. */
u_int64_t tc_frequency;
/* Frequency of the counter in Hz. */
char *tc_name;
/* Name of the timecounter. */
int tc_quality;
/*
* Used to determine if this timecounter is better than
* another timecounter higher means better. Negative
* means "only use at explicit request".
*/
void *tc_priv;
/* Pointer to the timecounter's private parts. */
struct timecounter *tc_next;
/* Pointer to the next timecounter. */
};
extern struct timecounter *timecounter;
u_int64_t tc_getfrequency(void);
void tc_init(struct timecounter *tc);
void tc_setclock(struct timespec *ts);
void tc_ticktock(void);
#ifdef SYSCTL_DECL
SYSCTL_DECL(_kern_timecounter);
#endif
#endif /* !_SYS_TIMETC_H_ */
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