1 /* semaphore.h 2 * 3 * Copyright 2012 Christopher Anderson <[email protected]> 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef __KERNEL_SEMAPHORE_H 18 #define __KERNEL_SEMAPHORE_H 19 20 #include <compiler.h> 21 #include <kernel/thread.h> 22 #include <kernel/mutex.h> 23 24 __BEGIN_CDECLS; 25 26 #define SEMAPHORE_MAGIC (0x73656D61) // 'sema' 27 28 typedef struct semaphore { 29 int magic; 30 int count; 31 wait_queue_t wait; 32 } semaphore_t; 33 34 #define SEMAPHORE_INITIAL_VALUE(s, _count) \ 35 { \ 36 .magic = SEMAPHORE_MAGIC, \ 37 .count = _count, \ 38 .wait = WAIT_QUEUE_INITIAL_VALUE((s).wait), \ 39 } 40 41 void sem_init(semaphore_t *, unsigned int); 42 void sem_destroy(semaphore_t *); 43 int sem_post(semaphore_t *, bool resched); 44 status_t sem_wait(semaphore_t *); 45 status_t sem_trywait(semaphore_t *); 46 status_t sem_timedwait(semaphore_t *, lk_time_t); 47 48 __END_CDECLS; 49 #endif 50