Annotation of sys/sys/timetc.h, Revision 1.1
1.1 ! nbrk 1: /*-
! 2: * ----------------------------------------------------------------------------
! 3: * "THE BEER-WARE LICENSE" (Revision 42):
! 4: * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
! 5: * can do whatever you want with this stuff. If we meet some day, and you think
! 6: * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
! 7: * ----------------------------------------------------------------------------
! 8: *
! 9: * $OpenBSD: timetc.h,v 1.2 2006/10/30 20:19:33 otto Exp $
! 10: * $FreeBSD: src/sys/sys/timetc.h,v 1.57 2003/04/10 23:07:24 des Exp $
! 11: */
! 12:
! 13: #ifndef _SYS_TIMETC_H_
! 14: #define _SYS_TIMETC_H_
! 15:
! 16: #ifndef _KERNEL
! 17: #error "no user-serviceable parts inside"
! 18: #endif
! 19:
! 20: /*-
! 21: * `struct timecounter' is the interface between the hardware which implements
! 22: * a timecounter and the MI code which uses this to keep track of time.
! 23: *
! 24: * A timecounter is a binary counter which has two properties:
! 25: * * it runs at a fixed, known frequency.
! 26: * * it has sufficient bits to not roll over in less than approximately
! 27: * max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta,
! 28: * for some indeterminate value of delta.)
! 29: */
! 30:
! 31: struct timecounter;
! 32: typedef u_int timecounter_get_t(struct timecounter *);
! 33: typedef void timecounter_pps_t(struct timecounter *);
! 34:
! 35: struct timecounter {
! 36: timecounter_get_t *tc_get_timecount;
! 37: /*
! 38: * This function reads the counter. It is not required to
! 39: * mask any unimplemented bits out, as long as they are
! 40: * constant.
! 41: */
! 42: timecounter_pps_t *tc_poll_pps;
! 43: /*
! 44: * This function is optional. It will be called whenever the
! 45: * timecounter is rewound, and is intended to check for PPS
! 46: * events. Normal hardware does not need it but timecounters
! 47: * which latch PPS in hardware (like sys/pci/xrpu.c) do.
! 48: */
! 49: u_int tc_counter_mask;
! 50: /* This mask should mask off any unimplemented bits. */
! 51: u_int64_t tc_frequency;
! 52: /* Frequency of the counter in Hz. */
! 53: char *tc_name;
! 54: /* Name of the timecounter. */
! 55: int tc_quality;
! 56: /*
! 57: * Used to determine if this timecounter is better than
! 58: * another timecounter higher means better. Negative
! 59: * means "only use at explicit request".
! 60: */
! 61: void *tc_priv;
! 62: /* Pointer to the timecounter's private parts. */
! 63: struct timecounter *tc_next;
! 64: /* Pointer to the next timecounter. */
! 65: int64_t tc_freq_adj;
! 66: /* Current frequency adjustment. */
! 67: };
! 68:
! 69: extern struct timecounter *timecounter;
! 70:
! 71: u_int64_t tc_getfrequency(void);
! 72: void tc_init(struct timecounter *tc);
! 73: void tc_setclock(struct timespec *ts);
! 74: void tc_ticktock(void);
! 75: void inittimecounter(void);
! 76: int sysctl_tc(int *, u_int, void *, size_t *, void *, size_t);
! 77: int tc_adjfreq(int64_t *, int64_t *);
! 78:
! 79: #endif /* !_SYS_TIMETC_H_ */
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