/* | |
FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* FreeRTOS tutorial books are available in pdf and paperback. * | |
* Complete, revised, and edited pdf reference manuals are also * | |
* available. * | |
* * | |
* Purchasing FreeRTOS documentation will not only help you, by * | |
* ensuring you get running as quickly as possible and with an * | |
* in-depth knowledge of how to use FreeRTOS, it will also help * | |
* the FreeRTOS project to continue with its mission of providing * | |
* professional grade, cross platform, de facto standard solutions * | |
* for microcontrollers - completely free of charge! * | |
* * | |
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< * | |
* * | |
* Thank you for using FreeRTOS, and thank you for your support! * | |
* * | |
*************************************************************************** | |
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. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/* | |
* Simple demonstration of the usage of counting semaphore. | |
*/ | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "semphr.h" | |
/* Demo program include files. */ | |
#include "countsem.h" | |
/* The maximum count value that the semaphore used for the demo can hold. */ | |
#define countMAX_COUNT_VALUE ( 200 ) | |
/* Constants used to indicate whether or not the semaphore should have been | |
created with its maximum count value, or its minimum count value. These | |
numbers are used to ensure that the pointers passed in as the task parameters | |
are valid. */ | |
#define countSTART_AT_MAX_COUNT ( 0xaa ) | |
#define countSTART_AT_ZERO ( 0x55 ) | |
/* Two tasks are created for the test. One uses a semaphore created with its | |
count value set to the maximum, and one with the count value set to zero. */ | |
#define countNUM_TEST_TASKS ( 2 ) | |
#define countDONT_BLOCK ( 0 ) | |
/*-----------------------------------------------------------*/ | |
/* Flag that will be latched to pdTRUE should any unexpected behaviour be | |
detected in any of the tasks. */ | |
static volatile portBASE_TYPE xErrorDetected = pdFALSE; | |
/*-----------------------------------------------------------*/ | |
/* | |
* The demo task. This simply counts the semaphore up to its maximum value, | |
* the counts it back down again. The result of each semaphore 'give' and | |
* 'take' is inspected, with an error being flagged if it is found not to be | |
* the expected result. | |
*/ | |
static void prvCountingSemaphoreTask( void *pvParameters ); | |
/* | |
* Utility function to increment the semaphore count value up from zero to | |
* countMAX_COUNT_VALUE. | |
*/ | |
static void prvIncrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter ); | |
/* | |
* Utility function to decrement the semaphore count value up from | |
* countMAX_COUNT_VALUE to zero. | |
*/ | |
static void prvDecrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter ); | |
/*-----------------------------------------------------------*/ | |
/* The structure that is passed into the task as the task parameter. */ | |
typedef struct COUNT_SEM_STRUCT | |
{ | |
/* The semaphore to be used for the demo. */ | |
xSemaphoreHandle xSemaphore; | |
/* Set to countSTART_AT_MAX_COUNT if the semaphore should be created with | |
its count value set to its max count value, or countSTART_AT_ZERO if it | |
should have been created with its count value set to 0. */ | |
unsigned portBASE_TYPE uxExpectedStartCount; | |
/* Incremented on each cycle of the demo task. Used to detect a stalled | |
task. */ | |
unsigned portBASE_TYPE uxLoopCounter; | |
} xCountSemStruct; | |
/* Two structures are defined, one is passed to each test task. */ | |
static volatile xCountSemStruct xParameters[ countNUM_TEST_TASKS ]; | |
/*-----------------------------------------------------------*/ | |
void vStartCountingSemaphoreTasks( void ) | |
{ | |
/* Create the semaphores that we are going to use for the test/demo. The | |
first should be created such that it starts at its maximum count value, | |
the second should be created such that it starts with a count value of zero. */ | |
xParameters[ 0 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, countMAX_COUNT_VALUE ); | |
xParameters[ 0 ].uxExpectedStartCount = countSTART_AT_MAX_COUNT; | |
xParameters[ 0 ].uxLoopCounter = 0; | |
xParameters[ 1 ].xSemaphore = xSemaphoreCreateCounting( countMAX_COUNT_VALUE, 0 ); | |
xParameters[ 1 ].uxExpectedStartCount = 0; | |
xParameters[ 1 ].uxLoopCounter = 0; | |
/* vQueueAddToRegistry() adds the semaphore to the registry, if one is | |
in use. The registry is provided as a means for kernel aware | |
debuggers to locate semaphores and has no purpose if a kernel aware debugger | |
is not being used. The call to vQueueAddToRegistry() will be removed | |
by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is | |
defined to be less than 1. */ | |
vQueueAddToRegistry( ( xQueueHandle ) xParameters[ 0 ].xSemaphore, ( signed portCHAR * ) "Counting_Sem_1" ); | |
vQueueAddToRegistry( ( xQueueHandle ) xParameters[ 1 ].xSemaphore, ( signed portCHAR * ) "Counting_Sem_2" ); | |
/* Were the semaphores created? */ | |
if( ( xParameters[ 0 ].xSemaphore != NULL ) || ( xParameters[ 1 ].xSemaphore != NULL ) ) | |
{ | |
/* Create the demo tasks, passing in the semaphore to use as the parameter. */ | |
xTaskCreate( prvCountingSemaphoreTask, ( signed portCHAR * ) "CNT1", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 0 ] ), tskIDLE_PRIORITY, NULL ); | |
xTaskCreate( prvCountingSemaphoreTask, ( signed portCHAR * ) "CNT2", configMINIMAL_STACK_SIZE, ( void * ) &( xParameters[ 1 ] ), tskIDLE_PRIORITY, NULL ); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvDecrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter ) | |
{ | |
unsigned portBASE_TYPE ux; | |
/* If the semaphore count is at its maximum then we should not be able to | |
'give' the semaphore. */ | |
if( xSemaphoreGive( xSemaphore ) == pdPASS ) | |
{ | |
xErrorDetected = pdTRUE; | |
} | |
/* We should be able to 'take' the semaphore countMAX_COUNT_VALUE times. */ | |
for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ ) | |
{ | |
if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) != pdPASS ) | |
{ | |
/* We expected to be able to take the semaphore. */ | |
xErrorDetected = pdTRUE; | |
} | |
( *puxLoopCounter )++; | |
} | |
#if configUSE_PREEMPTION == 0 | |
taskYIELD(); | |
#endif | |
/* If the semaphore count is zero then we should not be able to 'take' | |
the semaphore. */ | |
if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS ) | |
{ | |
xErrorDetected = pdTRUE; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvIncrementSemaphoreCount( xSemaphoreHandle xSemaphore, unsigned portBASE_TYPE *puxLoopCounter ) | |
{ | |
unsigned portBASE_TYPE ux; | |
/* If the semaphore count is zero then we should not be able to 'take' | |
the semaphore. */ | |
if( xSemaphoreTake( xSemaphore, countDONT_BLOCK ) == pdPASS ) | |
{ | |
xErrorDetected = pdTRUE; | |
} | |
/* We should be able to 'give' the semaphore countMAX_COUNT_VALUE times. */ | |
for( ux = 0; ux < countMAX_COUNT_VALUE; ux++ ) | |
{ | |
if( xSemaphoreGive( xSemaphore ) != pdPASS ) | |
{ | |
/* We expected to be able to take the semaphore. */ | |
xErrorDetected = pdTRUE; | |
} | |
( *puxLoopCounter )++; | |
} | |
#if configUSE_PREEMPTION == 0 | |
taskYIELD(); | |
#endif | |
/* If the semaphore count is at its maximum then we should not be able to | |
'give' the semaphore. */ | |
if( xSemaphoreGive( xSemaphore ) == pdPASS ) | |
{ | |
xErrorDetected = pdTRUE; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvCountingSemaphoreTask( void *pvParameters ) | |
{ | |
xCountSemStruct *pxParameter; | |
#ifdef USE_STDIO | |
void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend ); | |
const portCHAR * const pcTaskStartMsg = "Counting semaphore demo started.\r\n"; | |
/* Queue a message for printing to say the task has started. */ | |
vPrintDisplayMessage( &pcTaskStartMsg ); | |
#endif | |
/* The semaphore to be used was passed as the parameter. */ | |
pxParameter = ( xCountSemStruct * ) pvParameters; | |
/* Did we expect to find the semaphore already at its max count value, or | |
at zero? */ | |
if( pxParameter->uxExpectedStartCount == countSTART_AT_MAX_COUNT ) | |
{ | |
prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) ); | |
} | |
/* Now we expect the semaphore count to be 0, so this time there is an | |
error if we can take the semaphore. */ | |
if( xSemaphoreTake( pxParameter->xSemaphore, 0 ) == pdPASS ) | |
{ | |
xErrorDetected = pdTRUE; | |
} | |
for( ;; ) | |
{ | |
prvIncrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) ); | |
prvDecrementSemaphoreCount( pxParameter->xSemaphore, &( pxParameter->uxLoopCounter ) ); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xAreCountingSemaphoreTasksStillRunning( void ) | |
{ | |
static unsigned portBASE_TYPE uxLastCount0 = 0, uxLastCount1 = 0; | |
portBASE_TYPE xReturn = pdPASS; | |
/* Return fail if any 'give' or 'take' did not result in the expected | |
behaviour. */ | |
if( xErrorDetected != pdFALSE ) | |
{ | |
xReturn = pdFAIL; | |
} | |
/* Return fail if either task is not still incrementing its loop counter. */ | |
if( uxLastCount0 == xParameters[ 0 ].uxLoopCounter ) | |
{ | |
xReturn = pdFAIL; | |
} | |
else | |
{ | |
uxLastCount0 = xParameters[ 0 ].uxLoopCounter; | |
} | |
if( uxLastCount1 == xParameters[ 1 ].uxLoopCounter ) | |
{ | |
xReturn = pdFAIL; | |
} | |
else | |
{ | |
uxLastCount1 = xParameters[ 1 ].uxLoopCounter; | |
} | |
return xReturn; | |
} | |