FreeRTOS-Pooling-Server

Implement polling server for FreeRTOS

include/FreeRTOS.h - We've added a declaration for Macro portIS_ENDED_API (Line 509)
portable/MSVC-MingW/portmacro.h - We've added a declaration for Macro portIS_ENDED (Line 99)
	#define portIS_ENDED(pxTopOfStack) vIsEnded(pxTopOfStack)
	
portable/port.c - We've added a function "vIsEnded"

In file tasks.c:

// Update of struct tskTCB. We've added:
```
	unsigned long capacityC; // Task capacity
	unsigned long periodT;   // period of task
	unsigned long start;	  // Tick in which task has started
	unsigned long endT;   // Tick in which task has ended
	
	pdTASK_CODE pxTaskCode;   // Pointer to function that task should execute
	void *vParam;			  // Parameters that are passed to function
	
	
// Define struct aptskTCB. This struct describes aperiodic tasks.

	typedef struct aperiodicTaskControlBlock {
		unsigned long capacityC;	// capacity - execution time of aperiodic task, but it is not real time.
									// It is number how many CPU ticks it needs to be executed.
		unsigned long durationC;	// How long the task is executed
		pdTASK_CODE pxTaskCode;		// PPointer to function that task should execute
		void *vParam;				// Parameters of function
	} aptskTCB;


// Added some variables on lines 15 to 170

	PRIVILEGED_DATA static unsigned long serverCapacityC = 0;			// Max capacity of server
	PRIVILEGED_DATA static unsigned long serverCapacityCCurrent = 0;	// Current capacity of server
	PRIVILEGED_DATA static unsigned long serverPeriodT = 0;			// Server period
	PRIVILEGED_DATA static unsigned long serverWorkingTicks = 0;			// How much ticks has server been working in current period
	PRIVILEGED_DATA static unsigned long serverBeginWorking = 0;			// In which ticks scheduler switch on server
	PRIVILEGED_DATA static unsigned long serverLastTick = 0;			// Last server tick
	
	PRIVILEGED_DATA static unsigned long serverLastPeriod = ULONG_MAX;	// Time when server have been last time updated
	
	PRIVILEGED_DATA static tskTCB *serverTCB = 0;						// Pointer to TCB of server
	
	PRIVILEGED_DATA static xList pxReadyAperiodicTasksLists;		// Tasks that are ready for server to be executed i.e. tasks that server have taken
	PRIVILEGED_DATA static xList pxWaitingAperiodicTasksLists;		// All aperiodic tasks that are waiting for server to be executed
	PRIVILEGED_DATA static int areAperiodicListsInitialised = 0;	// Additional variable that we use to initialize above 2 lists
			
	

// Function vTaskStartScheduler(Linije od 110 do 1115) is key to start server. In fact it calls just xTaskCreate with correct parameters.

	static int runned = 0;
	if (runned == 0) { // Start server just one time
		serverTCB = (tskTCB*) malloc(sizeof(tskTCB));
	
		// Creating periodic task which function is prvServerTick.
		xTaskCreate(prvServerTick, (signed char * ) "Server",
				configMINIMAL_STACK_SIZE, NULL, uxPriority, &serverTCB, kapacitetC, periodaT);
		// Inicialize global parameters
		serverCapacityC = kapacitetC;
		serverCapacityCCurrent = kapacitetC; // Server at start have max capacity
		serverPeriodT = periodaT;
	}
	runned++;


// Declared function prvServerTick on line 425. Ova f-ja izvrsava kod servera

	static void prvServerTick();
	

// Implement function prvServerTick on line 1894. This function is execudet in server.

	void prvServerTick() {
		while (1) {
			printf("%lu (Server Message) Starting Next Task\n", xTaskGetTickCount());
			fflush(stdout);
	
			// Pick first task that is ready i.e. the one that is first in readyAperiodicTaskLists
			xListItem *curr = (&((&pxReadyAperiodicTasksLists)->xListEnd))->pxNext;
	
			//go through all ready tasks and execude them in order
			int i = 0;
			unsigned n = pxReadyAperiodicTasksLists.uxNumberOfItems;
			for (; i < n; ++i) {
				xListItem *next = curr->pxNext;
				aptskTCB *currentTCB = curr->pvOwner;
				(*currentTCB->pxTaskCode)(currentTCB->vParam);
	
				// When it's finished, remove him from ready list
				vListRemove(curr);
				curr = next;
			}
			// When you have finished everything - suspend me
			printf("%lu (Server Message) Server is suspended [No more tasks]\n",
					xTaskGetTickCount());
			fflush(stdout);
			vTaskSuspend(serverTCB);
		}
	}
	

// Implemented function xTaskCreateAperiodic in taks.c (line 607). But it is declared in task.h (line 1319). This function just add tasks in aperiodicTaskList

	void xTaskCreateAperiodic(pdTASK_CODE pvTaskCode, void *pvParameters,
		unsigned long capacityC) {
	
		// Allocate new aptskTCB
		aptskTCB *newTCB = (aptskTCB*) malloc(sizeof(aptskTCB));
		newTCB->capacityC = capacityC;
		newTCB->vParam = pvParameters;
		newTCB->pxTaskCode = pvTaskCode;
		newTCB->durationC = 0;
	
		// Allocate new waiting tasks list node
		xListItem *newItem = (xListItem*) malloc(sizeof(xListItem));
		newItem->pvOwner = newTCB;
		vListInitialiseItem(newItem); // Inicialize
		// If it's this function first time called, then initialize lists for waiting and ready tasks
		if (areAperiodicListsInitialised == 0) {
			vListInitialise(&pxWaitingAperiodicTasksLists);
			vListInitialise(&pxReadyAperiodicTasksLists);
			areAperiodicListsInitialised = 1;
		}
		// Put him in lists
		vListInsertEnd(&pxWaitingAperiodicTasksLists, newItem);
	}


// Function vTaskSwitchContext is the most important function in this project. See in code comment what does it do.

main.c: Everithing is ours