Merge branch 'mueller_BinSempahInterface' into mueller_framework

osal/FreeRTOS/BinarySemaphore.cpp

@@ -1,8 +1,3 @@
-/**
- * @file BinarySemaphore.cpp
- *
- * @date 25.02.2020
- */
 #include <framework/osal/FreeRTOS/BinarySemaphore.h>
 #include <framework/osal/FreeRTOS/TaskManagement.h>
 
@@ -11,8 +6,7 @@
 BinarySemaphore::BinarySemaphore() {
 	handle = xSemaphoreCreateBinary();
 	if(handle == nullptr) {
-
+		sif::error << "Semaphore: Binary semaph creation failure" << std::endl;
-		sif::error << "Binary semaphore creation failure" << std::endl;
 	}
 	xSemaphoreGive(handle);
 }
@@ -133,6 +127,17 @@ void BinarySemaphore::resetSemaphore() {
 	}
 }
 
+ReturnValue_t BinarySemaphore::acquire(uint32_t timeoutMs) {
+	return takeBinarySemaphore(timeoutMs);
+}
+
+ReturnValue_t BinarySemaphore::release() {
+	return giveBinarySemaphore();
+}
+
+uint8_t BinarySemaphore::getSemaphoreCounter() {
+	return uxSemaphoreGetCount(handle);
+}
 
 // Be careful with the stack size here. This is called from an ISR!
 ReturnValue_t BinarySemaphore::giveBinarySemaphoreFromISR(SemaphoreHandle_t semaphore,

osal/FreeRTOS/BinarySemaphore.h

@@ -1,30 +1,30 @@
-/**
- * @file BinarySempahore.h
- *
- * @date 25.02.2020
- */
 #ifndef FRAMEWORK_OSAL_FREERTOS_BINARYSEMPAHORE_H_
 #define FRAMEWORK_OSAL_FREERTOS_BINARYSEMPAHORE_H_
 
 #include <framework/returnvalues/HasReturnvaluesIF.h>
-
+#include <framework/tasks/SemaphoreIF.h>
 extern "C" {
-#include "FreeRTOS.h"
+#include <freertos/FreeRTOS.h>
-#include "semphr.h"
+#include <freertos/semphr.h>
 }
 
-
+// TODO: Counting semaphores and implement the new (better)
+//		 task notifications. However, those use task notifications require
+//		 the task handle. Maybe it would be better to make a separate class
+// 		 and switch between the classes with #ifdefs.
+//		 Task Notifications require FreeRTOS V8.2 something..
 /**
- * @brief OS Tool to achieve synchronization of between tasks or between task and ISR
+ * @brief 	OS Tool to achieve synchronization of between tasks or between
+ * 			task and ISR. The default semaphore implementation creates a
+ * 			binary semaphore, which can only be taken once.
  * @details
  * Documentation: https://www.freertos.org/Embedded-RTOS-Binary-Semaphores.html
  *
- * SHOULDDO: check freeRTOS version and use new task notifications,
+ * @author 	R. Mueller
- * if non-ancient freeRTOS version is used.
- *
  * @ingroup osal
  */
-class BinarySemaphore: public HasReturnvaluesIF {
+class BinarySemaphore: public SemaphoreIF,
+		public HasReturnvaluesIF {
 public:
 	static const uint8_t INTERFACE_ID = CLASS_ID::SEMAPHORE_IF;
 
@@ -37,39 +37,24 @@ public:
 	static constexpr TickType_t BLOCK_TIMEOUT_TICKS = portMAX_DELAY;
 	static constexpr uint32_t BLOCK_TIMEOUT = portMAX_DELAY;
 
-	//! Semaphore timeout
+	//! @brief Default ctor
-	static constexpr ReturnValue_t SEMAPHORE_TIMEOUT = MAKE_RETURN_CODE(1);
-	/** The current semaphore can not be given, because it is not owned */
-	static constexpr ReturnValue_t SEMAPHORE_NOT_OWNED = MAKE_RETURN_CODE(2);
-	static constexpr ReturnValue_t SEMAPHORE_NULLPOINTER = MAKE_RETURN_CODE(3);
-
 	BinarySemaphore();
-
+	//! @brief Copy ctor
-	/**
-	 * @brief Copy ctor
-	 */
 	BinarySemaphore(const BinarySemaphore&);
-
+	//! @brief Copy assignment
-	/**
-	 * @brief Copy assignment
-	 */
 	BinarySemaphore& operator=(const BinarySemaphore&);
-
+	//! @brief Move ctor
-	/**
-	 * @brief Move constructor
-	 */
 	BinarySemaphore (BinarySemaphore &&);
-
+	//! @brief Move assignment
-	/**
-	 * Move assignment
-	 */
 	BinarySemaphore & operator=(BinarySemaphore &&);
-
+	//! @brief Destructor
-	/**
-	 * Delete the binary semaphore to prevent a memory leak
-	 */
 	virtual ~BinarySemaphore();
 
+	ReturnValue_t acquire(uint32_t timeoutMs =
+	        BinarySemaphore::NO_BLOCK_TIMEOUT) override;
+	ReturnValue_t release() override;
+	uint8_t getSemaphoreCounter() override;
+
 	/**
 	 * Take the binary semaphore.
 	 * If the semaphore has already been taken, the task will be blocked
@@ -127,7 +112,8 @@ public:
 	 */
 	static ReturnValue_t giveBinarySemaphoreFromISR(SemaphoreHandle_t semaphore,
 				BaseType_t * higherPriorityTaskWoken);
-private:
+
+protected:
 	SemaphoreHandle_t handle;
 };
 

osal/FreeRTOS/CountingSemaphore.cpp

@@ -0,0 +1,26 @@
+#include <framework/osal/FreeRTOS/CountingSemaphore.h>
+#include <framework/serviceinterface/ServiceInterfaceStream.h>
+
+CountingSemaphore::CountingSemaphore(uint8_t count, uint8_t initCount):
+		count(count), initCount(initCount) {
+	handle = xSemaphoreCreateCounting(count, initCount);
+	if(handle == nullptr) {
+		sif::error << "CountingSemaphore: Creation failure" << std::endl;
+	}
+}
+
+CountingSemaphore::CountingSemaphore(CountingSemaphore&& other) {
+	handle = xSemaphoreCreateCounting(other.count, other.initCount);
+	if(handle == nullptr) {
+		sif::error << "CountingSemaphore: Creation failure" << std::endl;
+	}
+}
+
+CountingSemaphore& CountingSemaphore::operator =(
+		CountingSemaphore&& other) {
+	handle = xSemaphoreCreateCounting(other.count, other.initCount);
+	if(handle == nullptr) {
+		sif::error << "CountingSemaphore: Creation failure" << std::endl;
+	}
+	return * this;
+}

osal/FreeRTOS/CountingSemaphore.h

@@ -0,0 +1,29 @@
+#ifndef FRAMEWORK_OSAL_FREERTOS_COUNTINGSEMAPHORE_H_
+#define FRAMEWORK_OSAL_FREERTOS_COUNTINGSEMAPHORE_H_
+#include <framework/osal/FreeRTOS/BinarySemaphore.h>
+
+/**
+ * @brief 	Counting semaphores, which can be acquire more than once.
+ * @details
+ * See: https://www.freertos.org/CreateCounting.html
+ * API of counting semaphores is almost identical to binary semaphores,
+ * so we just inherit from binary semaphore and provide the respective
+ * constructors.
+ */
+class CountingSemaphore: public BinarySemaphore {
+public:
+	CountingSemaphore(uint8_t count, uint8_t initCount);
+	//! @brief Copy ctor, disabled
+	CountingSemaphore(const CountingSemaphore&) = delete;
+	//! @brief Copy assignment, disabled
+	CountingSemaphore& operator=(const CountingSemaphore&) = delete;
+	//! @brief Move ctor
+	CountingSemaphore (CountingSemaphore &&);
+	//! @brief Move assignment
+	CountingSemaphore & operator=(CountingSemaphore &&);
+private:
+	uint8_t count = 0;
+	uint8_t initCount = 0;
+};
+
+#endif /* FRAMEWORK_OSAL_FREERTOS_COUNTINGSEMAPHORE_H_ */

osal/FreeRTOS/MessageQueue.cpp

@@ -7,11 +7,10 @@
 // As a first step towards this, introduces system context variable which needs
 // to be switched manually
 // Haven't found function to find system context.
-MessageQueue::MessageQueue(size_t messageDepth, size_t maxMessageSize) :
+MessageQueue::MessageQueue(size_t messageDepth, size_t maxMessageSize) {
-defaultDestination(0),lastPartner(0), callContext(CallContext::task)  {
 	handle = xQueueCreate(messageDepth, maxMessageSize);
 	if (handle == NULL) {
-		sif::error << "MessageQueue creation failed" << std::endl;
+		sif::error << "MessageQueue: Creation failed" << std::endl;
 	}
 }
 
@@ -50,16 +49,18 @@ ReturnValue_t MessageQueue::reply(MessageQueueMessage* message) {
 ReturnValue_t MessageQueue::sendMessageFrom(MessageQueueId_t sendTo,
 		MessageQueueMessage* message, MessageQueueId_t sentFrom,
 		bool ignoreFault) {
-	return sendMessageFromMessageQueue(sendTo,message,sentFrom,ignoreFault, callContext);
+	return sendMessageFromMessageQueue(sendTo, message, sentFrom,
+			ignoreFault, callContext);
 }
 
 
 ReturnValue_t MessageQueue::handleSendResult(BaseType_t result, bool ignoreFault) {
 	if (result != pdPASS) {
-		if (!ignoreFault) {
+		if (not ignoreFault) {
-			InternalErrorReporterIF* internalErrorReporter = objectManager->get<InternalErrorReporterIF>(
+			InternalErrorReporterIF* internalErrorReporter =
+					objectManager->get<InternalErrorReporterIF>(
 					objects::INTERNAL_ERROR_REPORTER);
-			if (internalErrorReporter != NULL) {
+			if (internalErrorReporter != nullptr) {
 				internalErrorReporter->queueMessageNotSent();
 			}
 		}
@@ -78,7 +79,8 @@ ReturnValue_t MessageQueue::receiveMessage(MessageQueueMessage* message,
 }
 
 ReturnValue_t MessageQueue::receiveMessage(MessageQueueMessage* message) {
-	BaseType_t result = xQueueReceive(handle,reinterpret_cast<void*>(message->getBuffer()), 0);
+	BaseType_t result = xQueueReceive(handle,reinterpret_cast<void*>(
+			message->getBuffer()), 0);
 	if (result == pdPASS){
 		this->lastPartner = message->getSender();
 		return HasReturnvaluesIF::RETURN_OK;
@@ -103,6 +105,7 @@ MessageQueueId_t MessageQueue::getId() const {
 }
 
 void MessageQueue::setDefaultDestination(MessageQueueId_t defaultDestination) {
+	defaultDestinationSet = true;
 	this->defaultDestination = defaultDestination;
 }
 
@@ -111,7 +114,7 @@ MessageQueueId_t MessageQueue::getDefaultDestination() const {
 }
 
 bool MessageQueue::isDefaultDestinationSet() const {
-	return 0;
+	return defaultDestinationSet;
 }
 
 
@@ -126,9 +129,9 @@ ReturnValue_t MessageQueue::sendMessageFromMessageQueue(MessageQueueId_t sendTo,
                 static_cast<const void*>(message->getBuffer()), 0);
     }
     else {
-        // If the call context is from an interrupt,
+        /* If the call context is from an interrupt,
-        // request a context switch if a higher priority task
+         * request a context switch if a higher priority task
-        // was blocked by the interrupt.
+         * was blocked by the interrupt. */
         BaseType_t xHigherPriorityTaskWoken = pdFALSE;
         result = xQueueSendFromISR(reinterpret_cast<QueueHandle_t>(sendTo),
                 static_cast<const void*>(message->getBuffer()),

osal/FreeRTOS/MessageQueue.h

@@ -12,28 +12,30 @@ extern "C" {
 }
 
 
-
+// TODO: this class assumes that MessageQueueId_t is the same size as void*
-//TODO this class assumes that MessageQueueId_t is the same size as void* (the FreeRTOS handle type), compiler will catch this but it might be nice to have something checking or even an always working solution
+// (the FreeRTOS handle type), compiler will catch this but it might be nice
+// to have something checking or even an always working solution
 // https://scaryreasoner.wordpress.com/2009/02/28/checking-sizeof-at-compile-time/
 
 /**
- *	@brief		This class manages sending and receiving of message queue messages.
+ * @brief		This class manages sending and receiving of
- *
+ * 				message queue messages.
- *	@details	Message queues are used to pass asynchronous messages between processes.
+ * @details
+ * Message queues are used to pass asynchronous messages between processes.
  * They work like post boxes, where all incoming messages are stored in FIFO
  * order. This class creates a new receiving queue and provides methods to fetch
- *				received messages. Being a child of MessageQueueSender, this class also provides
+ * received messages. Being a child of MessageQueueSender, this class also
- *				methods to send a message to a user-defined or a default destination. In addition
+ * provides methods to send a message to a user-defined or a default destination.
- *				it also provides a reply method to answer to the queue it received its last message
+ * In addition it also provides a reply method to answer to the queue it
- *				from.
+ * received its last message from.
  *
- *				The MessageQueue should be used as "post box" for a single owning object. So all
+ * The MessageQueue should be used as "post box" for a single owning object.
- *				message queue communication is "n-to-one".
+ * So all message queue communication is "n-to-one".
- *				For creating the queue, as well as sending and receiving messages, the class makes
+ * For creating the queue, as well as sending and receiving messages, the class
- *				use of the operating system calls provided.
+ * makes use of the operating system calls provided.
  *
- *				Please keep in mind that FreeRTOS offers
+ * Please keep in mind that FreeRTOS offers different calls for message queue
- *				different calls for message queue operations if called from an ISR.
+ * operations if called from an ISR.
  * For now, the system context needs to be switched manually.
  * @ingroup osal
  * @ingroup message_queue
@@ -43,24 +45,38 @@ class MessageQueue : public MessageQueueIF {
 public:
 	/**
 	 * @brief	The constructor initializes and configures the message queue.
-	 * @details	By making use of the according operating system call, a message queue is created
+	 * @details
+	 * By making use of the according operating system call, a message queue is created
 	 * and initialized. The message depth - the maximum number of messages to be
 	 * buffered - may be set with the help of a parameter, whereas the message size is
 	 * automatically set to the maximum message queue message size. The operating system
 	 * sets the message queue id, or i case of failure, it is set to zero.
-	 * @param message_depth	The number of messages to be buffered before passing an error to the
+	 * @param message_depth
+	 * The number of messages to be buffered before passing an error to the
 	 * sender. Default is three.
-	 * @param max_message_size	With this parameter, the maximum message size can be adjusted.
+	 * @param max_message_size
+	 * With this parameter, the maximum message size can be adjusted.
 	 * This should be left default.
 	 */
-	MessageQueue( size_t message_depth = 3, size_t max_message_size = MessageQueueMessage::MAX_MESSAGE_SIZE );
+	MessageQueue( size_t messageDepth = 3,
+			size_t maxMessageSize = MessageQueueMessage::MAX_MESSAGE_SIZE );
+
+	/** Copying message queues forbidden */
+	MessageQueue(const MessageQueue&) = delete;
+	MessageQueue& operator=(const MessageQueue&) = delete;
 
 	/**
 	 * @brief	The destructor deletes the formerly created message queue.
-	 * @details	This is accomplished by using the delete call provided by the operating system.
+	 * @details	This is accomplished by using the delete call provided
+	 * 			by the operating system.
 	 */
 	virtual ~MessageQueue();
 
+	/**
+	 * This function is used to switch the call context. This has to be called
+	 * if a message is sent or received from an ISR!
+	 * @param callContext
+	 */
 	void switchSystemContext(CallContext callContext);
 
 	/**
@@ -90,27 +106,28 @@ public:
 	ReturnValue_t reply( MessageQueueMessage* message );
 
 	/**
-	 * \brief	With the sendMessage call, a queue message is sent to a receiving queue.
+	 * @brief	With the sendMessage call, a queue message is sent to a receiving queue.
-	 * \details	This method takes the message provided, adds the sentFrom information and passes
+	 * @details	This method takes the message provided, adds the sentFrom information and passes
 	 * 			it on to the destination provided with an operating system call. The OS's return
 	 * 			value is returned.
-	 * \param sendTo	This parameter specifies the message queue id to send the message to.
+	 * @param sendTo	This parameter specifies the message queue id to send the message to.
-	 * \param message	This is a pointer to a previously created message, which is sent.
+	 * @param message	This is a pointer to a previously created message, which is sent.
-	 * \param sentFrom	The sentFrom information can be set to inject the sender's queue id into the message.
+	 * @param sentFrom	The sentFrom information can be set to inject the sender's queue id into the message.
 	 * 					This variable is set to zero by default.
-	 * \param ignoreFault If set to true, the internal software fault counter is not incremented if queue is full.
+	 * @param ignoreFault If set to true, the internal software fault counter is not incremented if queue is full.
 	 */
 	virtual ReturnValue_t sendMessageFrom( MessageQueueId_t sendTo, MessageQueueMessage* message,
 			MessageQueueId_t sentFrom = NO_QUEUE, bool ignoreFault = false );
 
 	/**
-	 * \brief	The sendToDefault method sends a queue message to the default destination.
+	 * @brief	The sendToDefault method sends a queue message to the default destination.
-	 * \details	In all other aspects, it works identical to the sendMessage method.
+	 * @details	In all other aspects, it works identical to the sendMessage method.
-	 * \param message	This is a pointer to a previously created message, which is sent.
+	 * @param message	This is a pointer to a previously created message, which is sent.
-	 * \param sentFrom	The sentFrom information can be set to inject the sender's queue id into the message.
+	 * @param sentFrom	The sentFrom information can be set to inject the sender's queue id into the message.
 	 * 					This variable is set to zero by default.
 	 */
-	virtual ReturnValue_t sendToDefaultFrom( MessageQueueMessage* message, MessageQueueId_t sentFrom = NO_QUEUE, bool ignoreFault = false );
+	virtual ReturnValue_t sendToDefaultFrom( MessageQueueMessage* message,
+			MessageQueueId_t sentFrom = NO_QUEUE, bool ignoreFault = false );
 
 	/**
 	 * @brief	This function reads available messages from the message queue and returns the sender.
@@ -147,27 +164,38 @@ public:
 	MessageQueueId_t getId() const;
 
 	/**
+<<<<<<< HEAD
 	 * \brief	This method is a simple setter for the default destination.
+=======
+	 * @brief	This method is a simple setter for the default destination.
+>>>>>>> mueller_BinSempahInterface
 	 */
 	void setDefaultDestination(MessageQueueId_t defaultDestination);
 	/**
-	 * \brief	This method is a simple getter for the default destination.
+	 * @brief	This method is a simple getter for the default destination.
 	 */
 	MessageQueueId_t getDefaultDestination() const;
 
 	bool isDefaultDestinationSet() const;
 protected:
 	/**
-	 * Implementation to be called from any send Call within MessageQueue and MessageQueueSenderIF
+	 * @brief 	Implementation to be called from any send Call within
-	 * 	 \details	This method takes the message provided, adds the sentFrom information and passes
+	 * 			MessageQueue and MessageQueueSenderIF.
-	 * 			it on to the destination provided with an operating system call. The OS's return
+	 * @details
-	 * 			value is returned.
+	 * This method takes the message provided, adds the sentFrom information and
-	 * \param sendTo	This parameter specifies the message queue id to send the message to.
+	 * passes it on to the destination provided with an operating system call.
-	 * \param message	This is a pointer to a previously created message, which is sent.
+	 * The OS's return value is returned.
-	 * \param sentFrom	The sentFrom information can be set to inject the sender's queue id into the message.
+	 * @param sendTo
-	 * 					This variable is set to zero by default.
+	 * This parameter specifies the message queue id to send the message to.
-	 * \param ignoreFault If set to true, the internal software fault counter is not incremented if queue is full.
+	 * @param message
-	 * \param context
+	 * This is a pointer to a previously created message, which is sent.
+	 * @param sentFrom
+	 * The sentFrom information can be set to inject the sender's queue id into
+	 * the message. This variable is set to zero by default.
+	 * @param ignoreFault
+	 * If set to true, the internal software fault counter  is not incremented
+	 * if queue is full.
+	 * @param context Specify whether call is made from task or from an ISR.
 	 */
 	static ReturnValue_t sendMessageFromMessageQueue(MessageQueueId_t sendTo,
 			MessageQueueMessage* message, MessageQueueId_t sentFrom = NO_QUEUE,
@@ -175,12 +203,13 @@ protected:
 
 	static ReturnValue_t handleSendResult(BaseType_t result, bool ignoreFault);
 
-
 private:
+	bool defaultDestinationSet = false;
 	QueueHandle_t handle;
-	MessageQueueId_t defaultDestination;
+	MessageQueueId_t defaultDestination = 0;
-	MessageQueueId_t lastPartner;
+	MessageQueueId_t lastPartner = 0;
-	CallContext callContext; //!< Stores the current system context
+	//!< Stores the current system context
+	CallContext callContext =  CallContext::task;
 };
 
 #endif /* MESSAGEQUEUE_H_ */

osal/FreeRTOS/MutexFactory.cpp

@@ -1,9 +1,10 @@
 #include <framework/ipc/MutexFactory.h>
 #include <framework/osal/FreeRTOS/Mutex.h>
 
-//TODO: Different variant than the lazy loading in QueueFactory. What's better and why? -> one is on heap the other on bss/data
+//TODO: Different variant than the lazy loading in QueueFactory.
+//What's better and why? -> one is on heap the other on bss/data
 //MutexFactory* MutexFactory::factoryInstance = new MutexFactory();
-MutexFactory* MutexFactory::factoryInstance = NULL;
+MutexFactory* MutexFactory::factoryInstance = nullptr;
 
 MutexFactory::MutexFactory() {
 }
@@ -12,7 +13,7 @@ MutexFactory::~MutexFactory() {
 }
 
 MutexFactory* MutexFactory::instance() {
-	if (factoryInstance == NULL){
+	if (factoryInstance == nullptr){
 		factoryInstance = new MutexFactory();
 	}
 	return MutexFactory::factoryInstance;

osal/FreeRTOS/SemaphoreFactory.cpp

@@ -0,0 +1,33 @@
+#include <framework/osal/FreeRTOS/BinarySemaphore.h>
+#include <framework/osal/FreeRTOS/CountingSemaphore.h>
+#include <framework/tasks/SemaphoreFactory.h>
+#include <framework/serviceinterface/ServiceInterfaceStream.h>
+
+SemaphoreFactory* SemaphoreFactory::factoryInstance = nullptr;
+
+SemaphoreFactory::SemaphoreFactory() {
+}
+
+SemaphoreFactory::~SemaphoreFactory() {
+	delete factoryInstance;
+}
+
+SemaphoreFactory* SemaphoreFactory::instance() {
+	if (factoryInstance == nullptr){
+		factoryInstance = new SemaphoreFactory();
+	}
+	return SemaphoreFactory::factoryInstance;
+}
+
+SemaphoreIF* SemaphoreFactory::createBinarySemaphore() {
+	return new BinarySemaphore();
+}
+
+SemaphoreIF* SemaphoreFactory::createCountingSemaphore(uint8_t count,
+		uint8_t initCount) {
+	return new CountingSemaphore(count, initCount);
+}
+
+void SemaphoreFactory::deleteMutex(SemaphoreIF* semaphore) {
+	delete semaphore;
+}

osal/FreeRTOS/TaskManagement.cpp

@@ -4,7 +4,8 @@ void TaskManagement::requestContextSwitchFromTask() {
 	vTaskDelay(0);
 }
 
-void TaskManagement::requestContextSwitch(CallContext callContext = CallContext::task) {
+void TaskManagement::requestContextSwitch(
+		CallContext callContext = CallContext::task) {
 	if(callContext == CallContext::isr) {
 		// This function depends on the partmacro.h definition for the specific device
 		requestContextSwitchFromISR();
@@ -20,5 +21,3 @@ TaskHandle_t TaskManagement::getCurrentTaskHandle() {
 configSTACK_DEPTH_TYPE TaskManagement::getTaskStackHighWatermark() {
 	return uxTaskGetStackHighWaterMark(TaskManagement::getCurrentTaskHandle());
 }
-
-

osal/FreeRTOS/TaskManagement.h

@@ -18,9 +18,9 @@ extern "C" void requestContextSwitchFromISR();
 /*!
  * Used by functions to tell if they are being called from
  * within an ISR or from a regular task. This is required because FreeRTOS
- * has different functions for handling semaphores and messages from within an ISR and task.
+ * has different functions for handling semaphores and messages from within
+ * an ISR and task.
  */
-
 enum CallContext {
 	task = 0x00,//!< task_context
 	isr = 0xFF  //!< isr_context
@@ -30,10 +30,10 @@ enum CallContext {
 class TaskManagement {
 public:
 	/**
-	 * In this function, a function dependant on the portmacro.h header function calls
+	 * @brief	In this function, a function dependant on the portmacro.h header
-	 * to request a context switch can be specified.
+	 * 			function calls to request a context switch can be specified.
-	 * This can be used if sending to the queue from an ISR caused a task to unblock
+	 * This can be used if sending to the queue from an ISR caused a task
-	 * and a context switch is required.
+	 * to unblock and a context switch is required.
 	 */
 	static void requestContextSwitch(CallContext callContext);
 

tasks/SemaphoreFactory.h

@@ -0,0 +1,45 @@
+#ifndef FRAMEWORK_TASKS_SEMAPHOREFACTORY_H_
+#define FRAMEWORK_TASKS_SEMAPHOREFACTORY_H_
+#include <framework/tasks/SemaphoreIF.h>
+
+/**
+ * Creates Semaphore.
+ * This class is a "singleton" interface, i.e. it provides an
+ * interface, but also is the base class for a singleton.
+ */
+class SemaphoreFactory {
+public:
+	virtual ~SemaphoreFactory();
+	/**
+	 * Returns the single instance of SemaphoreFactory.
+	 * The implementation of #instance is found in its subclasses.
+	 * Thus, we choose link-time variability of the  instance.
+	 */
+	static SemaphoreFactory* instance();
+
+	/**
+	 * Create a binary semaphore.
+	 * Creator function for a binary semaphore which may only be acquired once
+	 * @return Pointer to newly created semaphore class instance.
+	 */
+	SemaphoreIF* createBinarySemaphore();
+	/**
+	 * Create a counting semaphore.
+	 * Creator functons for a counting semaphore which may be acquired multiple
+	 * times.
+	 * @param count Semaphore can be taken count times.
+	 * @param initCount Initial count value.
+	 * @return
+	 */
+	SemaphoreIF* createCountingSemaphore(uint8_t count, uint8_t initCount);
+	void deleteMutex(SemaphoreIF* mutex);
+
+private:
+	/**
+	 * External instantiation is not allowed.
+	 */
+	SemaphoreFactory();
+	static SemaphoreFactory* factoryInstance;
+};
+
+#endif /* FRAMEWORK_TASKS_SEMAPHOREFACTORY_H_ */

tasks/SemaphoreIF.h

@@ -0,0 +1,58 @@
+#ifndef FRAMEWORK_TASKS_SEMAPHOREIF_H_
+#define FRAMEWORK_TASKS_SEMAPHOREIF_H_
+#include <framework/returnvalues/FwClassIds.h>
+#include <framework/returnvalues/HasReturnvaluesIF.h>
+#include <cstdint>
+
+/**
+ * @brief 	Generic interface for semaphores, which can be used to achieve
+ * 			task synchronization. This is a generic interface which can be
+ * 			used for both binary semaphores and counting semaphores.
+ * @details
+ * A semaphore is a synchronization primitive.
+ * See: https://en.wikipedia.org/wiki/Semaphore_(programming)
+ * A semaphore can be used to achieve task synchonization and track the
+ * availability of resources.
+ *
+ * If mutual exlcusion of a resource is desired, a mutex should be used,
+ * which is a special form of a semaphore and has an own interface.
+ */
+class SemaphoreIF {
+public:
+	virtual~ SemaphoreIF() {};
+	//!< Needs to be defined in implementation.
+	static const uint32_t NO_TIMEOUT;
+	static const uint8_t INTERFACE_ID = CLASS_ID::SEMAPHORE_IF;
+	//! Semaphore timeout
+	static constexpr ReturnValue_t SEMAPHORE_TIMEOUT = MAKE_RETURN_CODE(1);
+	//! The current semaphore can not be given, because it is not owned
+	static constexpr ReturnValue_t SEMAPHORE_NOT_OWNED = MAKE_RETURN_CODE(2);
+	static constexpr ReturnValue_t SEMAPHORE_NULLPOINTER = MAKE_RETURN_CODE(3);
+
+	/**
+	 * Generic call to acquire a semaphore.
+	 * If there are no more semaphores to be taken (for a counting semaphore,
+	 * a semaphore may be taken more than once), the taks will block
+	 * for a maximum of timeoutMs while trying to acquire the semaphore.
+	 * This can be used to achieve task synchrnization.
+	 * @param timeoutMs
+	 * @return - c RETURN_OK for successfull acquisition
+	 */
+	virtual ReturnValue_t acquire(uint32_t timeoutMs) = 0;
+
+	/**
+	 * Corrensponding call to release a semaphore.
+	 * @return -@c RETURN_OK for successfull release
+	 */
+	virtual ReturnValue_t release() = 0;
+
+	/**
+	 * If the semaphore is a counting semaphore then the semaphores current
+	 * count value is returned. If the semaphore is a binary semaphore then 1
+	 * is returned if the semaphore is available, and 0 is returned if the
+	 * semaphore is not available.
+	 */
+	virtual uint8_t getSemaphoreCounter() = 0;
+};
+
+#endif /* FRAMEWORK_TASKS_SEMAPHOREIF_H_ */