116 lines
3.9 KiB
C++
116 lines
3.9 KiB
C++
/**
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* @file PollingTask.h
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*
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* @brief This file contains the definition for the PollingTask class.
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*
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* @author Claas Ziemke, Bastian Baetz
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*
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* @date 17.03.2011
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*
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* Copyright 2009,2010, Claas Ziemke <claas.ziemke@gmx.net>
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* All rights reserved
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*
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*/
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#ifndef POLLINGTASK_H_
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#define POLLINGTASK_H_
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#include <framework/devicehandlers/PollingSequence.h>
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#include <framework/tasks/TaskBase.h>
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/**
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*
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* @brief This class represents a specialized thread to execute polling sequences.
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*
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* @image latex seq_PST_dynamic.eps "Sequence diagram of polling sequence operation" width=1@textwidth
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* @image html seq_PST_dynamic.png "Sequence diagram of polling sequence operation"
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*
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* @details The Polling Sequence Table is executed in a task of special type, called PollingTask.
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* After creation the polling task initializes the PST and starts taskFunctionality.
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* An infinite loop is entered within which the iteration through the PST is done by repetitive calls of
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* getInterval() and pollAndAdvance().
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* @ingroup task_handling
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*/
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class PollingTask: public TaskBase {
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protected:
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/**
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* @brief id of the associated OS period
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*/
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PeriodId_t periodId;
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/**
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* @brief This attribute is the pointer to the complete polling sequence table object.
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*
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* @details The most important attribute of the thread object.
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* It holds a pointer to the complete polling sequence table object.
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*/
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PollingSequence* pst;
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/**
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* @brief This attribute holds a function pointer that is executed when a deadline was missed.
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*
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* @details Another function may be announced to determine the actions to perform when a deadline was missed.
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* Currently, only one function for missing any deadline is allowed.
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* If not used, it shall be declared NULL.
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*/
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void ( *deadlineMissedFunc )( void );
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/**
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* @brief This is the entry point in a new polling thread.
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*
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* @details This method, that is the general entry point in the new thread, is here set to generate
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* and link the Polling Sequence Table to the thread object and start taskFunctionality()
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* on success. If operation of the task is ended for some reason,
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* the destructor is called to free allocated memory.
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*/
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static TaskReturn_t taskEntryPoint( TaskArgument_t argument );
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/**
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* @brief This function holds the main functionality of the thread.
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*
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*
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* @details Holding the main functionality of the task, this method is most important.
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* It links the functionalities provided by PollingSequence with the OS's System Calls
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* to keep the timing of the periods.
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*/
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void taskFunctionality( void );
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public:
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/**
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* @brief The standard constructor of the class.
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*
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* @details This is the general constructor of the class. In addition to the TaskBase parameters,
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* the following variables are passed:
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*
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* @param (*setDeadlineMissedFunc)() The function pointer to the deadline missed function that shall be assigned.
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*
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* @param getPst The object id of the completely initialized polling sequence.
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*/
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PollingTask( const char *name, TaskPriority_t setPriority, size_t setStack, void (*setDeadlineMissedFunc)(), object_id_t getPst );
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/**
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* @brief The destructor of the class.
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*
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* @details The destructor frees all heap memory that was allocated on thread initialization for the PST and
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* the device handlers. This is done by calling the PST's destructor.
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*/
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virtual ~PollingTask( void );
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/**
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* @brief The function to actually start a new task.
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*
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* @details As described in TaskBase this method invokes the operating systems method to start a new task.
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* Entry point is taskEntryPoint().
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*/
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ReturnValue_t startTask( void );
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/**
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* This static function can be used as #deadlineMissedFunc.
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* It counts missedDeadlines and prints the number of missed deadlines every 10th time.
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*/
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static void missedDeadlineCounter();
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/**
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* A helper variable to count missed deadlines.
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*/
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static uint32_t deadlineMissedCount;
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};
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#endif /* POLLINGTASK_H_ */
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