uvisor_semaphore.c

00001 #include "api/inc/uvisor_semaphore_exports.h"
00002 #include "api/inc/uvisor_exports.h"
00003 #include "api/inc/halt_exports.h"
00004 #include "cmsis_os.h"
00005 #include <string.h>
00006 
00007 typedef struct uvisor_semaphore_internal {
00008     osSemaphoreId id;
00009     osSemaphoreDef_t def;
00010     uint32_t data[2]; /* RTX expects this is 4-byte aligned */
00011 } UVISOR_ALIGN(4) uvisor_semaphore_internal_t;
00012 
00013 UVISOR_STATIC_ASSERT(UVISOR_SEMAPHORE_INTERNAL_SIZE >= sizeof(UvisorSemaphore), semaphore_size_too_small);
00014 
00015 int __uvisor_semaphore_init(UvisorSemaphore * s, int32_t count)
00016 {
00017     uvisor_semaphore_internal_t * semaphore = (uvisor_semaphore_internal_t *) s;
00018 
00019     memset(semaphore->data, 0, sizeof(semaphore->data));
00020     semaphore->def.semaphore = semaphore->data;
00021     semaphore->id = osSemaphoreCreate(&semaphore->def, count);
00022 
00023     /* Error when semaphore->id is NULL */
00024     return semaphore->id == NULL ? UVISOR_ERROR_OUT_OF_STRUCTURES : 0;
00025 }
00026 
00027 int __uvisor_semaphore_pend(UvisorSemaphore * s, uint32_t timeout_ms)
00028 {
00029     uvisor_semaphore_internal_t * semaphore = (uvisor_semaphore_internal_t *) s;
00030 
00031     int32_t num_available_tokens = osSemaphoreWait(semaphore->id, timeout_ms);
00032 
00033     if (num_available_tokens == -1) {
00034         return UVISOR_ERROR_INVALID_PARAMETERS;
00035     }
00036 
00037     if (num_available_tokens == 0) {
00038         return UVISOR_ERROR_TIMEOUT;
00039     }
00040 
00041     return 0;
00042 }
00043 
00044 int __uvisor_semaphore_post(UvisorSemaphore * s) {
00045     uvisor_semaphore_internal_t * semaphore = (uvisor_semaphore_internal_t *) s;
00046     return osSemaphoreRelease(semaphore->id);
00047 }