1 /* $OpenBSD: timeout.h,v 1.16 2003/06/03 01:27:31 art Exp $ */
2 /*
3 * Copyright (c) 2000-2001 Artur Grabowski <art@openbsd.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
16 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
17 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
18 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #ifndef _SYS_TIMEOUT_H_
28 #define _SYS_TIMEOUT_H_
29
30 /*
31 * Interface for handling time driven events in the kernel.
32 *
33 * The basic component of this API is the struct timeout. The user should not
34 * touch the internals of this structure, but it's the users responsibility
35 * to allocate and deallocate timeouts.
36 *
37 * The functions used to manipulate timeouts are:
38 * - timeout_set(timeout, function, argument)
39 * Initializes a timeout struct to call the function with the argument.
40 * A timeout only needs to be initialized once.
41 * - timeout_add(timeout, ticks)
42 * Schedule this timeout to run in "ticks" ticks (there are hz ticks in
43 * one second). You may not touch the timeout with timeout_set once the
44 * timeout is scheduled. A second call to timeout_add with an already
45 * scheduled timeout will cause the old timeout to be canceled and the
46 * new will be scheduled.
47 * - timeout_del(timeout)
48 * Remove the timeout from the timeout queue. It's legal to remove
49 * a timeout that has already happened.
50 *
51 * These functions may be called in interrupt context (anything below splhigh).
52 */
53
54 struct circq {
55 struct circq *next; /* next element */
56 struct circq *prev; /* previous element */
57 };
58
59 struct timeout {
60 struct circq to_list; /* timeout queue, don't move */
61 void (*to_func)(void *); /* function to call */
62 void *to_arg; /* function argument */
63 int to_time; /* ticks on event */
64 int to_flags; /* misc flags */
65 };
66
67 /*
68 * flags in the to_flags field.
69 */
70 #define TIMEOUT_ONQUEUE 2 /* timeout is on the todo queue */
71 #define TIMEOUT_INITIALIZED 4 /* timeout is initialized */
72 #define TIMEOUT_TRIGGERED 8 /* timeout is running or ran */
73 /*
74 * special macros
75 *
76 * timeout_pending(to) - is this timeout already scheduled to run?
77 * timeout_initialized(to) - is this timeout initialized?
78 */
79 #define timeout_pending(to) ((to)->to_flags & TIMEOUT_ONQUEUE)
80 #define timeout_initialized(to) ((to)->to_flags & TIMEOUT_INITIALIZED)
81 #define timeout_triggered(to) ((to)->to_flags & TIMEOUT_TRIGGERED)
82
83 #ifdef _KERNEL
84 void timeout_set(struct timeout *, void (*)(void *), void *);
85 void timeout_add(struct timeout *, int);
86 void timeout_del(struct timeout *);
87
88 void timeout_startup(void);
89
90 /*
91 * called once every hardclock. returns non-zero if we need to schedule a
92 * softclock.
93 */
94 int timeout_hardclock_update(void);
95 #endif /* _KERNEL */
96
97 #endif /* _SYS_TIMEOUT_H_ */