1 /*
2 * Copyright (c) 2008-2014 Travis Geiselbrecht
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files
6 * (the "Software"), to deal in the Software without restriction,
7 * including without limitation the rights to use, copy, modify, merge,
8 * publish, distribute, sublicense, and/or sell copies of the Software,
9 * and to permit persons to whom the Software is furnished to do so,
10 * subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23 #ifndef __KERNEL_EVENT_H
24 #define __KERNEL_EVENT_H
25
26 #include <compiler.h>
27 #include <stdbool.h>
28 #include <sys/types.h>
29 #include <kernel/thread.h>
30
31 __BEGIN_CDECLS;
32
33 #define EVENT_MAGIC (0x65766E74) // "evnt"
34
35 typedef struct event {
36 int magic;
37 bool signaled;
38 uint flags;
39 wait_queue_t wait;
40 } event_t;
41
42 #define EVENT_FLAG_AUTOUNSIGNAL 1
43
44 #define EVENT_INITIAL_VALUE(e, initial, _flags) \
45 { \
46 .magic = EVENT_MAGIC, \
47 .signaled = initial, \
48 .flags = _flags, \
49 .wait = WAIT_QUEUE_INITIAL_VALUE((e).wait), \
50 }
51
52 /* Rules for Events:
53 * - Events may be signaled from interrupt context *but* the reschedule
54 * parameter must be false in that case.
55 * - Events may not be waited upon from interrupt context.
56 * - Events without FLAG_AUTOUNSIGNAL:
57 * - Wake up any waiting threads when signaled.
58 * - Continue to do so (no threads will wait) until unsignaled.
59 * - Events with FLAG_AUTOUNSIGNAL:
60 * - If one or more threads are waiting when signaled, one thread will
61 * be woken up and return. The signaled state will not be set.
62 * - If no threads are waiting when signaled, the Event will remain
63 * in the signaled state until a thread attempts to wait (at which
64 * time it will unsignal atomicly and return immediately) or
65 * event_unsignal() is called.
66 */
67
68 void event_init(event_t *, bool initial, uint flags);
69 void event_destroy(event_t *);
70 status_t event_wait_timeout(event_t *, lk_time_t); /* wait on the event with a timeout */
71 status_t event_signal(event_t *, bool reschedule);
72 status_t event_unsignal(event_t *);
73
event_initialized(event_t * e)74 static inline bool event_initialized(event_t *e)
75 {
76 return e->magic == EVENT_MAGIC;
77 }
78
event_wait(event_t * e)79 static inline status_t event_wait(event_t *e)
80 {
81 return event_wait_timeout(e, INFINITE_TIME);
82 }
83
84 __END_CDECLS;
85
86 #endif
87
88