1/* $OpenBSD: timetc.h,v 1.14 2023/02/04 19:19:35 cheloha Exp $ */
2
3/*
4 * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19/*
20 * If we meet some day, and you think this stuff is worth it, you
21 * can buy me a beer in return. Poul-Henning Kamp
22 */
23
24#ifndef _SYS_TIMETC_H_
25#define _SYS_TIMETC_H_
26
27#if !defined(_KERNEL) && !defined(_LIBC)
28#error "no user-serviceable parts inside"
29#endif
30
31#include <machine/timetc.h>
32#include <sys/queue.h>
33
34/*-
35 * `struct timecounter' is the interface between the hardware which implements
36 * a timecounter and the MI code which uses this to keep track of time.
37 *
38 * A timecounter is a binary counter which has two properties:
39 * * it runs at a fixed, known frequency.
40 * * it has sufficient bits to not roll over in less than approximately
41 * max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta,
42 * for some indeterminate value of delta.)
43 */
44
45struct timecounter;
46typedef u_int timecounter_get_t(struct timecounter *);
47
48/*
49 * Locks used to protect struct members in this file:
50 * I immutable after initialization
51 * T tc_lock
52 * W windup_mtx
53 */
54
55struct timecounter {
56 timecounter_get_t *tc_get_timecount; /* [I] */
57 /*
58 * This function reads the counter. It is not required to
59 * mask any unimplemented bits out, as long as they are
60 * constant.
61 */
62 u_int tc_counter_mask; /* [I] */
63 /* This mask should mask off any unimplemented bits. */
64 u_int64_t tc_frequency; /* [I] */
65 /* Frequency of the counter in Hz. */
66 char *tc_name; /* [I] */
67 /* Name of the timecounter. */
68 int tc_quality; /* [I] */
69 /*
70 * Used to determine if this timecounter is better than
71 * another timecounter higher means better. Negative
72 * means "only use at explicit request".
73 */
74 void *tc_priv; /* [I] */
75 /* Pointer to the timecounter's private parts. */
76 int tc_user; /* [I] */
77 /* Expose this timecounter to userland. */
78 SLIST_ENTRY(timecounter) tc_next; /* [I] */
79 /* Pointer to the next timecounter. */
80 int64_t tc_freq_adj; /* [T,W] */
81 /* Current frequency adjustment. */
82 u_int64_t tc_precision; /* [I] */
83 /* Precision of the counter. Computed in tc_init(). */
84};
85
86struct timekeep {
87 /* set at initialization */
88 uint32_t tk_version; /* version number */
89
90 /* timehands members */
91 uint64_t tk_scale;
92 u_int tk_offset_count;
93 struct bintime tk_offset;
94 struct bintime tk_naptime;
95 struct bintime tk_boottime;
96 volatile u_int tk_generation;
97
98 /* timecounter members */
99 int tk_user;
100 u_int tk_counter_mask;
101};
102#define TK_VERSION 0
103
104struct rwlock;
105extern struct rwlock tc_lock;
106
107extern struct timecounter *timecounter;
108
109extern struct uvm_object *timekeep_object;
110extern struct timekeep *timekeep;
111
112u_int64_t tc_getfrequency(void);
113u_int64_t tc_getprecision(void);
114void tc_init(struct timecounter *tc);
115void tc_reset_quality(struct timecounter *, int);
116void tc_setclock(const struct timespec *ts);
117void tc_setrealtimeclock(const struct timespec *ts);
118void tc_ticktock(void);
119void inittimecounter(void);
120int sysctl_tc(int *, u_int, void *, size_t *, void *, size_t);
121void tc_adjfreq(int64_t *, int64_t *);
122void tc_adjtime(int64_t *, int64_t *);
123
124#endif /* !_SYS_TIMETC_H_ */