88 lines
2.8 KiB
C
88 lines
2.8 KiB
C
/*
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* Copyright (c) 2008-2014 Travis Geiselbrecht
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef __KERNEL_EVENT_H
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#define __KERNEL_EVENT_H
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#include <compiler.h>
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#include <stdbool.h>
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#include <sys/types.h>
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#include <kernel/thread.h>
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__BEGIN_CDECLS
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#define EVENT_MAGIC (0x65766E74) // "evnt"
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typedef struct event {
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int magic;
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bool signaled;
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uint flags;
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wait_queue_t wait;
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} event_t;
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#define EVENT_FLAG_AUTOUNSIGNAL 1
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#define EVENT_INITIAL_VALUE(e, initial, _flags) \
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{ \
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.magic = EVENT_MAGIC, \
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.signaled = initial, \
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.flags = _flags, \
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.wait = WAIT_QUEUE_INITIAL_VALUE((e).wait), \
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}
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/* Rules for Events:
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* - Events may be signaled from interrupt context *but* the reschedule
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* parameter must be false in that case.
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* - Events may not be waited upon from interrupt context.
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* - Events without FLAG_AUTOUNSIGNAL:
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* - Wake up any waiting threads when signaled.
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* - Continue to do so (no threads will wait) until unsignaled.
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* - Events with FLAG_AUTOUNSIGNAL:
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* - If one or more threads are waiting when signaled, one thread will
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* be woken up and return. The signaled state will not be set.
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* - If no threads are waiting when signaled, the Event will remain
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* in the signaled state until a thread attempts to wait (at which
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* time it will unsignal atomicly and return immediately) or
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* event_unsignal() is called.
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*/
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void event_init(event_t *, bool initial, uint flags);
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void event_destroy(event_t *);
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status_t event_wait_timeout(event_t *, lk_time_t); /* wait on the event with a timeout */
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status_t event_signal(event_t *, bool reschedule);
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status_t event_unsignal(event_t *);
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static inline bool event_initialized(event_t *e)
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{
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return e->magic == EVENT_MAGIC;
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}
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static inline status_t event_wait(event_t *e)
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{
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return event_wait_timeout(e, INFINITE_TIME);
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}
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__END_CDECLS
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#endif
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