1 /* Copyright (c) 2012, The Linux Foundation. All rights reserved. 2 * 3 * Redistribution and use in source and binary forms, with or without 4 * modification, are permitted provided that the following conditions are 5 * met: 6 * * Redistributions of source code must retain the above copyright 7 * notice, this list of conditions and the following disclaimer. 8 * * Redistributions in binary form must reproduce the above 9 * copyright notice, this list of conditions and the following 10 * disclaimer in the documentation and/or other materials provided 11 * with the distribution. 12 * * Neither the name of The Linux Foundation nor the names of its 13 * contributors may be used to endorse or promote products derived 14 * from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 23 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 25 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN 26 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 */ 29 30 #ifndef __QCAMERA_SEMAPHORE_H__ 31 #define __QCAMERA_SEMAPHORE_H__ 32 33 #ifdef __cplusplus 34 extern "C" { 35 #endif 36 37 /* Implement semaphore with mutex and conditional variable. 38 * Reason being, POSIX semaphore on Android are not used or 39 * well tested. 40 */ 41 42 typedef struct { 43 int val; 44 pthread_mutex_t mutex; 45 pthread_cond_t cond; 46 } cam_semaphore_t; 47 48 static inline void cam_sem_init(cam_semaphore_t *s, int n) 49 { 50 pthread_mutex_init(&(s->mutex), NULL); 51 pthread_cond_init(&(s->cond), NULL); 52 s->val = n; 53 } 54 55 static inline void cam_sem_post(cam_semaphore_t *s) 56 { 57 pthread_mutex_lock(&(s->mutex)); 58 s->val++; 59 pthread_cond_signal(&(s->cond)); 60 pthread_mutex_unlock(&(s->mutex)); 61 } 62 63 static inline int cam_sem_wait(cam_semaphore_t *s) 64 { 65 int rc = 0; 66 pthread_mutex_lock(&(s->mutex)); 67 while (s->val == 0) 68 rc = pthread_cond_wait(&(s->cond), &(s->mutex)); 69 s->val--; 70 pthread_mutex_unlock(&(s->mutex)); 71 return rc; 72 } 73 74 static inline void cam_sem_destroy(cam_semaphore_t *s) 75 { 76 pthread_mutex_destroy(&(s->mutex)); 77 pthread_cond_destroy(&(s->cond)); 78 s->val = 0; 79 } 80 81 #ifdef __cplusplus 82 } 83 #endif 84 85 #endif /* __QCAMERA_SEMAPHORE_H__ */ 86
