68 lines
2.2 KiB
C
68 lines
2.2 KiB
C
/*-
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*/
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#ifndef _SYS_TIMETC_H_
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#define _SYS_TIMETC_H_
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#ifndef _KERNEL
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#error "no user-serviceable parts inside"
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#endif
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/*-
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* `struct timecounter' is the interface between the hardware which implements
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* a timecounter and the MI code which uses this to keep track of time.
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*
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* A timecounter is a binary counter which has two properties:
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* * it runs at a fixed, known frequency.
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* * it has sufficient bits to not roll over in less than approximately
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* max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta,
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* for some indeterminate value of delta.)
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*/
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struct timecounter;
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typedef u_int timecounter_get_t(struct timecounter *);
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typedef void timecounter_pps_t(struct timecounter *);
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struct timecounter {
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timecounter_get_t *tc_get_timecount;
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/*
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* This function reads the counter. It is not required to
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* mask any unimplemented bits out, as long as they are
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* constant.
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*/
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timecounter_pps_t *tc_poll_pps;
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/*
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* This function is optional. It will be called whenever the
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* timecounter is rewound, and is intended to check for PPS
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* events. Normal hardware does not need it but timecounters
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* which latch PPS in hardware (like sys/pci/xrpu.c) do.
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*/
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u_int tc_counter_mask;
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/* This mask should mask off any unimplemented bits. */
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u_int64_t tc_frequency;
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/* Frequency of the counter in Hz. */
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char *tc_name;
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/* Name of the timecounter. */
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void *tc_priv;
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/* Pointer to the timecounter's private parts. */
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struct timecounter *tc_next;
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/* Pointer to the next timecounter. */
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};
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extern struct timecounter *timecounter;
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u_int64_t tc_getfrequency(void);
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void tc_init(struct timecounter *tc);
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void tc_setclock(struct timespec *ts);
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void tc_ticktock(void);
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#endif /* !_SYS_TIMETC_H_ */
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