FreeRTOS-Kernel/FreeRTOS/Demo/Common/Minimal/QueueOverwrite.c

/*
    FreeRTOS V8.2.2 - Copyright (C) 2015 Real Time Engineers Ltd.
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.

    ***************************************************************************
    >>!   NOTE: The modification to the GPL is included to allow you to     !<<
    >>!   distribute a combined work that includes FreeRTOS without being   !<<
    >>!   obliged to provide the source code for proprietary components     !<<
    >>!   outside of the FreeRTOS kernel.                                   !<<
    ***************************************************************************

    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    FOR A PARTICULAR PURPOSE.  Full license text is available on the following
    link: http://www.freertos.org/a00114.html

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that is more than just the market leader, it     *
     *    is the industry's de facto standard.                               *
     *                                                                       *
     *    Help yourself get started quickly while simultaneously helping     *
     *    to support the FreeRTOS project by purchasing a FreeRTOS           *
     *    tutorial book, reference manual, or both:                          *
     *    http://www.FreeRTOS.org/Documentation                              *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
    the FAQ page "My application does not run, what could be wrong?".  Have you
    defined configASSERT()?

    http://www.FreeRTOS.org/support - In return for receiving this top quality
    embedded software for free we request you assist our global community by
    participating in the support forum.

    http://www.FreeRTOS.org/training - Investing in training allows your team to
    be as productive as possible as early as possible.  Now you can receive
    FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
    Ltd, and the world's leading authority on the world's leading RTOS.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
    Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

    http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
    Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and commercial middleware.

    http://www.SafeRTOS.com - High Integrity Systems also provide a safety
    engineered and independently SIL3 certified version for use in safety and
    mission critical applications that require provable dependability.

    1 tab == 4 spaces!
*/

/*
 * Basic task to demonstrate the xQueueOverwrite() function.  See the comments
 * in the function itself.
 */

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

/* Demo program include files. */
#include "QueueOverwrite.h"

/* A block time of 0 just means "don't block". */
#define qoDONT_BLOCK		0

/* Number of times to overwrite the value in the queue. */
#define qoLOOPS			5

/* The task that uses the queue. */
static void prvQueueOverwriteTask( void *pvParameters );

/* Variable that is incremented on each loop of prvQueueOverwriteTask() provided
prvQueueOverwriteTask() has not found any errors. */
static uint32_t ulLoopCounter = 0;

/* Set to pdFALSE if an error is discovered by the
vQueueOverwritePeriodicISRDemo() function. */
static BaseType_t xISRTestStatus = pdPASS;

/* The queue that is accessed from the ISR.  The queue accessed by the task is
created inside the task itself. */
static QueueHandle_t xISRQueue = NULL;

/*-----------------------------------------------------------*/

void vStartQueueOverwriteTask( UBaseType_t uxPriority )
{
const UBaseType_t uxQueueLength = 1;

	/* Create the queue used by the ISR.  xQueueOverwriteFromISR() should only
	be used on queues that have a length of 1. */
	xISRQueue = xQueueCreate( uxQueueLength, ( UBaseType_t ) sizeof( uint32_t ) );

	/* Create the test task.  The queue used by the test task is created inside
	the task itself. */
	xTaskCreate( prvQueueOverwriteTask, "QOver", configMINIMAL_STACK_SIZE, NULL, uxPriority, ( TaskHandle_t * ) NULL );
}
/*-----------------------------------------------------------*/

static void prvQueueOverwriteTask( void *pvParameters )
{
QueueHandle_t xTaskQueue;
const UBaseType_t uxQueueLength = 1;
uint32_t ulValue, ulStatus = pdPASS, x;

	/* The parameter is not used. */
	( void ) pvParameters;

	/* Create the queue.  xQueueOverwrite() should only be used on queues that
	have a length of 1. */
	xTaskQueue = xQueueCreate( uxQueueLength, ( UBaseType_t ) sizeof( uint32_t ) );
	configASSERT( xTaskQueue );

	for( ;; )
	{
		/* The queue is empty.  Writing to the queue then reading from the queue
		should return the item written. */
		ulValue = 10;
		xQueueOverwrite( xTaskQueue, &ulValue );

		ulValue = 0;
		xQueueReceive( xTaskQueue, &ulValue, qoDONT_BLOCK );

		if( ulValue != 10 )
		{
			ulStatus = pdFAIL;
		}

		/* Now try writing to the queue several times.  Each time the value
		in the queue should get overwritten. */
		for( x = 0; x < qoLOOPS; x++ )
		{
			/* Write to the queue. */
			xQueueOverwrite( xTaskQueue, &x );

			/* Check the value in the queue is that written, even though the
			queue was not necessarily empty. */
			xQueuePeek( xTaskQueue, &ulValue, qoDONT_BLOCK );
			if( ulValue != x )
			{
				ulStatus = pdFAIL;
			}

			/* There should always be one item in the queue. */
			if( uxQueueMessagesWaiting( xTaskQueue ) != uxQueueLength )
			{
				ulStatus = pdFAIL;
			}
		}

		/* Empty the queue again. */
		xQueueReceive( xTaskQueue, &ulValue, qoDONT_BLOCK );

		if( uxQueueMessagesWaiting( xTaskQueue ) != 0 )
		{
			ulStatus = pdFAIL;
		}

		if( ulStatus != pdFAIL )
		{
			/* Increment a counter to show this task is still running without
			error. */
			ulLoopCounter++;
		}

		#if( configUSE_PREEMPTION == 0 )
			taskYIELD();
		#endif
	}
}
/*-----------------------------------------------------------*/

BaseType_t xIsQueueOverwriteTaskStillRunning( void )
{
BaseType_t xReturn;

	if( xISRTestStatus != pdPASS )
	{
		xReturn = pdFAIL;
	}
	else if( ulLoopCounter > 0 )
	{
		xReturn = pdPASS;
	}
	else
	{
		/* The task has either stalled of discovered an error. */
		xReturn = pdFAIL;
	}

	ulLoopCounter = 0;

	return xReturn;
}
/*-----------------------------------------------------------*/

void vQueueOverwritePeriodicISRDemo( void )
{
static uint32_t ulCallCount = 0;
const uint32_t ulTx1 = 10UL, ulTx2 = 20UL, ulNumberOfSwitchCases = 3UL;
uint32_t ulRx;

	/* This function should be called from an interrupt, such as the tick hook
	function vApplicationTickHook(). */

	configASSERT( xISRQueue );

	switch( ulCallCount )
	{
		case 0:
			/* The queue is empty.  Write ulTx1 to the queue.  In this demo the
			last parameter is not used because there are no tasks blocked on
			this queue. */
			xQueueOverwriteFromISR( xISRQueue, &ulTx1, NULL );

			/* Peek the queue to check it holds the expected value. */
			xQueuePeekFromISR( xISRQueue, &ulRx );
			if( ulRx != ulTx1 )
			{
				xISRTestStatus = pdFAIL;
			}
			break;

		case 1:
			/* The queue already holds ulTx1.  Overwrite the value in the queue
			with ulTx2. */
			xQueueOverwriteFromISR( xISRQueue, &ulTx2, NULL );
			break;

		case 2:
			/* Read from the queue to empty the queue again.  The value read
			should be ulTx2. */
			xQueueReceiveFromISR( xISRQueue, &ulRx, NULL );

			if( ulRx != ulTx2 )
			{
				xISRTestStatus = pdFAIL;
			}
			break;
	}

	/* Run the next case in the switch statement above next time this function
	is called. */
	ulCallCount++;

	if( ulCallCount >= ulNumberOfSwitchCases )
	{
		/* Go back to the start. */
		ulCallCount = 0;
	}
}