mutex.c

/*
* Copyright (c) 2014-2016, Siemens AG. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <embb/base/c/mutex.h>
#include <embb/base/c/thread.h>
#include <assert.h>

#include <embb/base/c/internal/unused.h>

#ifdef EMBB_PLATFORM_THREADING_WINTHREADS

int embb_mutex_init(embb_mutex_t* mutex, int type) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	/* Critical sections in Windows are always recursive */
	InitializeCriticalSection(mutex);
	EMBB_UNUSED(type);
	return EMBB_SUCCESS;
}

int embb_mutex_lock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	EnterCriticalSection(mutex);
	return EMBB_SUCCESS;
}

int embb_mutex_try_lock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	BOOL success;
	success = TryEnterCriticalSection(mutex);
	if (success == FALSE) return EMBB_ERROR;
	return EMBB_SUCCESS;
}

int embb_mutex_unlock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	LeaveCriticalSection(mutex);
	return EMBB_SUCCESS;
}

void embb_mutex_destroy(embb_mutex_t* mutex) {
	assert(NULL != mutex);
	DeleteCriticalSection(mutex);
}

#endif /* EMBB_PLATFORM_THREADING_WINTHREADS */

#ifdef EMBB_PLATFORM_THREADING_POSIXTHREADS

int embb_mutex_init(embb_mutex_t* mutex, int type) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	if (type == EMBB_MUTEX_PLAIN) {
		if (pthread_mutex_init(mutex, NULL) != 0) return EMBB_ERROR;
	} else {
		assert(type == EMBB_MUTEX_RECURSIVE);
		pthread_mutexattr_t attributes;
		if (pthread_mutexattr_init(&attributes) != 0) return EMBB_ERROR;
		if (pthread_mutexattr_settype(&attributes, PTHREAD_MUTEX_RECURSIVE) != 0) {
			pthread_mutexattr_destroy(&attributes);
			return EMBB_ERROR;
		}
		if (pthread_mutex_init(mutex, &attributes) != 0) {
			pthread_mutexattr_destroy(&attributes);
			return EMBB_ERROR;
		}
		if (pthread_mutexattr_destroy(&attributes) != 0) return EMBB_ERROR;
	}
	return EMBB_SUCCESS;
}

int embb_mutex_lock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	int result = pthread_mutex_lock(mutex);
	if (result != 0) {
		return EMBB_ERROR;
	}
	return EMBB_SUCCESS;
}

int embb_mutex_try_lock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	int result = pthread_mutex_trylock(mutex);
	if (result == 0) {
		return EMBB_SUCCESS;
	}
	if (result == EBUSY) {
		return EMBB_BUSY;
	}
	return EMBB_ERROR;
}

int embb_mutex_unlock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	int result = pthread_mutex_unlock(mutex);
	if (result != 0) {
		return EMBB_ERROR;
	}
	return EMBB_SUCCESS;
}

void embb_mutex_destroy(embb_mutex_t* mutex) {
	assert(NULL != mutex);
	pthread_mutex_destroy(mutex);
}

#endif /* EMBB_PLATFORM_THREADING_POSIXTHREADS */


#ifdef EMBB_PLATFORM_THREADING_RTOSTASKS

#include <FreeRTOS/semphr.h>
#include <FreeRTOS/portmacro.h>

int embb_mutex_init(embb_mutex_t* mutex, int type) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}

	/*
	 * scm34681:
	 * Type of mutex cannot be determined from SemaphoreHandle_t,
	 * but mutex gets locked with two different functions. 
	 * ==> only recursive mutexes are used. 
	 * Check Queue_t for type checking. Queue_t not defined in queue.h
	 * but queue.c...
	 */
	/*if(type == EMBB_MUTEX_PLAIN) {
		*mutex = xSemaphoreCreateMutex();
	}
	else {
		assert(type == EMBB_MUTEX_RECURSIVE);*/
		*mutex = xSemaphoreCreateRecursiveMutex();
	/*}*/
	
	EMBB_UNUSED(type);
	
	if(mutex == NULL) {
		return EMBB_ERROR;
	}
	
	return EMBB_SUCCESS;
}

int embb_mutex_lock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	int result = xSemaphoreTakeRecursive(*mutex, portMAX_DELAY);
	if (result != 1) return EMBB_ERROR;
	return EMBB_SUCCESS;
}

int embb_mutex_try_lock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	
	int result = xSemaphoreTakeRecursive(*mutex, 0);
	if (result != 1) return EMBB_ERROR;
	return EMBB_SUCCESS;
}

int embb_mutex_unlock(embb_mutex_t* mutex) {
	if (NULL == mutex) {
		return EMBB_ERROR;
	}
	int result = xSemaphoreGiveRecursive(*mutex);
	if(result != 1) return EMBB_ERROR;
	return EMBB_SUCCESS;
}

void embb_mutex_destroy(embb_mutex_t* mutex) {
	assert(NULL != mutex);
	vSemaphoreDelete(*mutex);
}


#endif /* EMBB_PLATFORM_THREADING_RTOSTASKS */

int embb_spin_init(embb_spinlock_t* spinlock) {
	if (NULL == spinlock) {
		return EMBB_ERROR;
	}
	// For now, store the initial value. In the future will use atomic init
	// function (as soon as available).
	embb_atomic_store_int(&spinlock->atomic_spin_variable_, 0);
	return EMBB_SUCCESS;
}

int embb_spin_lock(embb_spinlock_t* spinlock) {
	if (NULL == spinlock) {
		return EMBB_ERROR;
	}
	int expected = 0;
	int spins = 1;

	// try to swap the
	while (0 == embb_atomic_compare_and_swap_int(
	&spinlock->atomic_spin_variable_, &expected, 1)) {
		if (0 == (spins & 1023)) {
			embb_thread_yield();
		}
		spins++;
		// reset expected, as CAS might change it...
		expected = 0;
	}
	return EMBB_SUCCESS;
}

int embb_spin_try_lock(embb_spinlock_t* spinlock,
unsigned int max_number_spins) {
	if (NULL == spinlock) {
		return EMBB_ERROR;
	}
	if (max_number_spins == 0)
	return EMBB_BUSY;

	int expected = 0;
	while (0 == embb_atomic_compare_and_swap_int(
	&spinlock->atomic_spin_variable_,
	&expected, 1)) {
		max_number_spins--;
		if (0 == max_number_spins) {
			return EMBB_BUSY;
		}
		expected = 0;
	}

	return EMBB_SUCCESS;
}

int embb_spin_unlock(embb_spinlock_t* spinlock) {
	if (NULL == spinlock) {
		return EMBB_ERROR;
	}
	int expected = 1;
	return embb_atomic_compare_and_swap_int(&spinlock->atomic_spin_variable_,
	&expected, 0) ?
	EMBB_SUCCESS : EMBB_ERROR;
}

void embb_spin_destroy(embb_spinlock_t* spinlock) {
	assert(NULL != spinlock);
	// for now, doing nothing here... in future, will call the respective
	// destroy function for atomics...
	EMBB_UNUSED(spinlock);
}