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_ */