1 /******************************************************************************
2 *
3 * Copyright (C) 2015 Google, Inc.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 ******************************************************************************/
18
19
20 #include "osi/semaphore.h"
21
22 /*-----------------------------------------------------------------------------------*/
23 // Creates and returns a new semaphore. The "init_count" argument specifies
24 // the initial state of the semaphore, "max_count" specifies the maximum value
25 // that can be reached.
osi_sem_new(osi_sem_t * sem,uint32_t max_count,uint32_t init_count)26 int osi_sem_new(osi_sem_t *sem, uint32_t max_count, uint32_t init_count)
27 {
28 int ret = -1;
29
30 if (sem) {
31 *sem = xSemaphoreCreateCounting(max_count, init_count);
32 if ((*sem) != NULL) {
33 ret = 0;
34 }
35 }
36
37 return ret;
38 }
39
40 /*-----------------------------------------------------------------------------------*/
41 // Give a semaphore
osi_sem_give(osi_sem_t * sem)42 void osi_sem_give(osi_sem_t *sem)
43 {
44 xSemaphoreGive(*sem);
45 }
46
47 /*
48 Blocks the thread while waiting for the semaphore to be
49 signaled. If the "timeout" argument is non-zero, the thread should
50 only be blocked for the specified time (measured in
51 milliseconds).
52
53 */
54 int
osi_sem_take(osi_sem_t * sem,uint32_t timeout)55 osi_sem_take(osi_sem_t *sem, uint32_t timeout)
56 {
57 int ret = 0;
58
59 if (timeout == OSI_SEM_MAX_TIMEOUT) {
60 if (xSemaphoreTake(*sem, portMAX_DELAY) != pdTRUE) {
61 ret = -1;
62 }
63 } else {
64 if (xSemaphoreTake(*sem, timeout / portTICK_PERIOD_MS) != pdTRUE) {
65 ret = -2;
66 }
67 }
68
69 return ret;
70 }
71
72 // Deallocates a semaphore
osi_sem_free(osi_sem_t * sem)73 void osi_sem_free(osi_sem_t *sem)
74 {
75 vSemaphoreDelete(*sem);
76 *sem = NULL;
77 }
78
