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323 lines
12 KiB
C
323 lines
12 KiB
C
/*
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FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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All rights reserved
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that has become a de facto standard. *
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* *
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* Help yourself get started quickly and support the FreeRTOS *
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* project by purchasing a FreeRTOS tutorial book, reference *
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* manual, or both from: http://www.FreeRTOS.org/Documentation *
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* *
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* Thank you! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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>>! NOTE: The modification to the GPL is included to allow you to distribute
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>>! a combined work that includes FreeRTOS without being obliged to provide
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>>! the source code for proprietary components outside of the FreeRTOS
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>>! kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. Full license text is available from the following
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link: http://www.freertos.org/a00114.html
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1 tab == 4 spaces!
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***************************************************************************
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* *
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* Having a problem? Start by reading the FAQ "My application does *
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* not run, what could be wrong?" *
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* *
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* http://www.FreeRTOS.org/FAQHelp.html *
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* *
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***************************************************************************
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http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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license and Real Time Engineers Ltd. contact details.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and middleware.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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1 tab == 4 spaces!
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*/
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/*
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* Simple demonstration of the usage of counting semaphore.
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*/
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "semphr.h"
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/* Demo program include files. */
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#include "countsem.h"
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/* The maximum count value that the semaphore used for the demo can hold. */
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#define countMAX_COUNT_VALUE ( 200 )
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/* Constants used to indicate whether or not the semaphore should have been
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created with its maximum count value, or its minimum count value. These
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numbers are used to ensure that the pointers passed in as the task parameters
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are valid. */
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#define countSTART_AT_MAX_COUNT ( 0xaa )
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#define countSTART_AT_ZERO ( 0x55 )
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/* Two tasks are created for the test. One uses a semaphore created with its
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count value set to the maximum, and one with the count value set to zero. */
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#define countNUM_TEST_TASKS ( 2 )
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#define countDONT_BLOCK ( 0 )
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/*-----------------------------------------------------------*/
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/* Flag that will be latched to pdTRUE should any unexpected behaviour be
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detected in any of the tasks. */
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static volatile portBASE_TYPE xErrorDetected = pdFALSE;
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/*-----------------------------------------------------------*/
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/*
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* The demo task. This simply counts the semaphore up to its maximum value,
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* the counts it back down again. The result of each semaphore 'give' and
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* 'take' is inspected, with an error being flagged if it is found not to be
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* the expected result.
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*/
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static void prvCountingSemaphoreTask( void *pvParameters );
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/*
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* Utility function to increment the semaphore count value up from zero to
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* countMAX_COUNT_VALUE.
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*/
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static void prvIncrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter );
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/*
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* Utility function to decrement the semaphore count value up from
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* countMAX_COUNT_VALUE to zero.
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*/
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static void prvDecrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter );
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/*-----------------------------------------------------------*/
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/* The structure that is passed into the task as the task parameter. */
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typedef struct COUNT_SEM_STRUCT
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{
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/* The semaphore to be used for the demo. */
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xSemaphoreHandle xSemaphore;
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/* Set to countSTART_AT_MAX_COUNT if the semaphore should be created with
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its count value set to its max count value, or countSTART_AT_ZERO if it
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should have been created with its count value set to 0. */
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unsigned portBASE_TYPE uxExpectedStartCount;
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/* Incremented on each cycle of the demo task. Used to detect a stalled
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task. */
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unsigned portBASE_TYPE uxLoopCounter;
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} xCountSemStruct;
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/* Two structures are defined, one is passed to each test task. */
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static volatile xCountSemStruct xParameters[ countNUM_TEST_TASKS ];
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/*-----------------------------------------------------------*/
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void vStartCountingSemaphoreTasks( void )
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{
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/* Create the semaphores that we are going to use for the test/demo. The
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first should be created such that it starts at its maximum count value,
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the second should be created such that it starts with a count value of zero. */
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xParameters[ 0 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, countMAX_COUNT_VALUE );
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xParameters[ 0 ].uxExpectedStartCount = countSTART_AT_MAX_COUNT;
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xParameters[ 0 ].uxLoopCounter = 0;
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xParameters[ 1 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, 0 );
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xParameters[ 1 ].uxExpectedStartCount = 0;
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xParameters[ 1 ].uxLoopCounter = 0;
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/* vQueueAddToRegistry() adds the semaphore to the registry, if one is
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in use. The registry is provided as a means for kernel aware
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debuggers to locate semaphores and has no purpose if a kernel aware debugger
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is not being used. The call to vQueueAddToRegistry() will be removed
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by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is
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defined to be less than 1. */
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vQueueAddToRegistry( ( xQueueHandle ) xParameters[ 0 ].xSemaphore, ( signed portCHAR * ) "Counting_Sem_1" );
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vQueueAddToRegistry( ( xQueueHandle ) xParameters[ 1 ].xSemaphore, ( signed portCHAR * ) "Counting_Sem_2" );
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/* Were the semaphores created? */
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if( ( xParameters[ 0 ].xSemaphore != NULL ) || ( xParameters[ 1 ].xSemaphore != NULL ) )
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{
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/* Create the demo tasks, passing in the semaphore to use as the parameter. */
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xTaskCreate( prvCountingSemaphoreTask, ( signed portCHAR * ) "CNT1", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 0 ] ), tskIDLE_PRIORITY, NULL );
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xTaskCreate( prvCountingSemaphoreTask, ( signed portCHAR * ) "CNT2", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 1 ] ), tskIDLE_PRIORITY, NULL );
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}
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}
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/*-----------------------------------------------------------*/
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static void prvDecrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter )
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{
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unsigned portBASE_TYPE ux;
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/* If the semaphore count is at its maximum then we should not be able to
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'give' the semaphore. */
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if( xSemaphoreGive( xSemaphore ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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/* We should be able to 'take' the semaphore countMAX_COUNT_VALUE times. */
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for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ )
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{
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if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) != pdPASS )
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{
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/* We expected to be able to take the semaphore. */
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xErrorDetected = pdTRUE;
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}
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( *puxLoopCounter )++;
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}
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#if configUSE_PREEMPTION == 0
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taskYIELD();
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#endif
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/* If the semaphore count is zero then we should not be able to 'take'
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the semaphore. */
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if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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}
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/*-----------------------------------------------------------*/
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static void prvIncrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter )
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{
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unsigned portBASE_TYPE ux;
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/* If the semaphore count is zero then we should not be able to 'take'
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the semaphore. */
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if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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/* We should be able to 'give' the semaphore countMAX_COUNT_VALUE times. */
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for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ )
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{
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if( xSemaphoreGive( xSemaphore ) != pdPASS )
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{
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/* We expected to be able to take the semaphore. */
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xErrorDetected = pdTRUE;
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}
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( *puxLoopCounter )++;
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}
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#if configUSE_PREEMPTION == 0
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taskYIELD();
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#endif
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/* If the semaphore count is at its maximum then we should not be able to
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'give' the semaphore. */
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if( xSemaphoreGive( xSemaphore ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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}
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/*-----------------------------------------------------------*/
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static void prvCountingSemaphoreTask( void *pvParameters )
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{
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xCountSemStruct *pxParameter;
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#ifdef USE_STDIO
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void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
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const portCHAR * const pcTaskStartMsg = "Counting semaphore demo started.\r\n";
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/* Queue a message for printing to say the task has started. */
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vPrintDisplayMessage( &pcTaskStartMsg );
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#endif
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/* The semaphore to be used was passed as the parameter. */
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pxParameter = ( xCountSemStruct * ) pvParameters;
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/* Did we expect to find the semaphore already at its max count value, or
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at zero? */
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if( pxParameter->uxExpectedStartCount == countSTART_AT_MAX_COUNT )
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{
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prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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}
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/* Now we expect the semaphore count to be 0, so this time there is an
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error if we can take the semaphore. */
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if( xSemaphoreTake( pxParameter->xSemaphore, 0 ) == pdPASS )
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{
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xErrorDetected = pdTRUE;
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}
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for( ;; )
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{
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prvIncrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) );
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}
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xAreCountingSemaphoreTasksStillRunning( void )
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{
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static unsigned portBASE_TYPE uxLastCount0 = 0, uxLastCount1 = 0;
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portBASE_TYPE xReturn = pdPASS;
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/* Return fail if any 'give' or 'take' did not result in the expected
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behaviour. */
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if( xErrorDetected != pdFALSE )
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{
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xReturn = pdFAIL;
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}
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/* Return fail if either task is not still incrementing its loop counter. */
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if( uxLastCount0 == xParameters[ 0 ].uxLoopCounter )
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{
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xReturn = pdFAIL;
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}
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else
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{
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uxLastCount0 = xParameters[ 0 ].uxLoopCounter;
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}
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if( uxLastCount1 == xParameters[ 1 ].uxLoopCounter )
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{
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xReturn = pdFAIL;
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}
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else
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{
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uxLastCount1 = xParameters[ 1 ].uxLoopCounter;
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}
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return xReturn;
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}
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