Mbed OS Reference | equeue_platform.h Source File

 /*
  * System specific implementation
  *
  * Copyright (c) 2016-2019 ARM Limited
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 #ifndef EQUEUE_PLATFORM_H
 #define EQUEUE_PLATFORM_H
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 #include <stdbool.h>
 #include <stdint.h>
 
 // Currently supported platforms
 //
 // Uncomment to select a supported platform or reimplement this file
 // for a specific target.
 //#define EQUEUE_PLATFORM_POSIX
 //#define EQUEUE_PLATFORM_MBED
 
 // Try to infer a platform if none was manually selected
 #if !defined(EQUEUE_PLATFORM_POSIX)     \
  && !defined(EQUEUE_PLATFORM_MBED)
 #if defined(__unix__)
 #define EQUEUE_PLATFORM_POSIX
 #elif defined(__MBED__)
 #define EQUEUE_PLATFORM_MBED
 #else
 #warning "Unknown platform! Please update equeue_platform.h"
 #endif
 #endif
 
 // Platform includes
 #if defined(EQUEUE_PLATFORM_POSIX)
 #include <pthread.h>
 #elif defined(EQUEUE_PLATFORM_MBED) && defined(MBED_CONF_RTOS_PRESENT)
 #include "cmsis_os2.h"
 #include "mbed_rtos_storage.h"
 #endif
 
 
 // Platform millisecond counter
 //
 // Return a tick that represents the number of milliseconds that have passed
 // since an arbitrary point in time. The granularity does not need to be at
 // the millisecond level, however the accuracy of the equeue library is
 // limited by the accuracy of this tick.
 //
 // Must intentionally overflow to 0 after 2^32-1
 void equeue_tick_init(void);
 unsigned equeue_tick(void);
 
 
 // Platform mutex type
 //
 // The equeue library requires at minimum a non-recursive mutex that is
 // safe in interrupt contexts. The mutex section is help for a bounded
 // amount of time, so simply disabling interrupts is acceptable
 //
 // If irq safety is not required, a regular blocking mutex can be used.
 #if defined(EQUEUE_PLATFORM_POSIX)
 typedef pthread_mutex_t equeue_mutex_t;
 #elif defined(EQUEUE_PLATFORM_WINDOWS)
 typedef CRITICAL_SECTION equeue_mutex_t;
 #elif defined(EQUEUE_PLATFORM_MBED)
 typedef unsigned equeue_mutex_t;
 #elif defined(EQUEUE_PLATFORM_FREERTOS)
 typedef UBaseType_t equeue_mutex_t;
 #endif
 
 // Platform mutex operations
 //
 // The equeue_mutex_create and equeue_mutex_destroy manage the lifetime
 // of the mutex. On error, equeue_mutex_create should return a negative
 // error code.
 //
 // The equeue_mutex_lock and equeue_mutex_unlock lock and unlock the
 // underlying mutex.
 int equeue_mutex_create(equeue_mutex_t *mutex);
 void equeue_mutex_destroy(equeue_mutex_t *mutex);
 void equeue_mutex_lock(equeue_mutex_t *mutex);
 void equeue_mutex_unlock(equeue_mutex_t *mutex);
 
 
 // Platform semaphore type
 //
 // The equeue library requires a binary semaphore type that can be safely
 // signaled from interrupt contexts and from inside a equeue_mutex section.
 //
 // The equeue_signal_wait is relied upon by the equeue library to sleep the
 // processor between events. Spurious wakeups have no negative-effects.
 //
 // A counting semaphore will also work, however may cause the event queue
 // dispatch loop to run unnecessarily. For that matter, equeue_signal_wait
 // may even be implemented as a single return statement.
 #if defined(EQUEUE_PLATFORM_POSIX)
 typedef struct equeue_sema {
     pthread_mutex_t mutex;
     pthread_cond_t cond;
     bool signal;
 } equeue_sema_t;
 #elif defined(EQUEUE_PLATFORM_MBED) && MBED_CONF_RTOS_API_PRESENT
 typedef struct equeue_sema {
     // We will actually store a C++ rtos:EventQueue in here;
     // attempt to match layout for storage, and assert size in equeue_mbed.cpp
 #if MBED_CONF_RTOS_PRESENT
     osEventFlagsId_t                _id;
     mbed_rtos_storage_event_flags_t _obj_mem;
 #else
     uint32_t _flags;
 #endif
 } equeue_sema_t;
 #elif defined(EQUEUE_PLATFORM_MBED)
 typedef int equeue_sema_t;
 #endif
 
 // Platform semaphore operations
 //
 // The equeue_sema_create and equeue_sema_destroy manage the lifetime
 // of the semaphore. On error, equeue_sema_create should return a negative
 // error code.
 //
 // The equeue_sema_signal marks a semaphore as signalled such that the next
 // equeue_sema_wait will return true.
 //
 // The equeue_sema_wait waits for a semaphore to be signalled or returns
 // immediately if equeue_sema_signal had been called since the last
 // equeue_sema_wait. The equeue_sema_wait returns true if it detected that
 // equeue_sema_signal had been called. If ms is negative, equeue_sema_wait
 // will wait for a signal indefinitely.
 int equeue_sema_create(equeue_sema_t *sema);
 void equeue_sema_destroy(equeue_sema_t *sema);
 void equeue_sema_signal(equeue_sema_t *sema);
 bool equeue_sema_wait(equeue_sema_t *sema, int ms);
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif
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