root/webserver/example/freeRTOS/Demo/Common/Minimal/AltBlock.c

/*
        FreeRTOS V5.4.1 - Copyright (C) 2009 Real Time Engineers Ltd.

        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 exception 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.  
        Alternative commercial license and support terms are also available upon 
        request.  See the licensing section of http://www.FreeRTOS.org for full 
        license details.

        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 along
        with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
        Temple Place, Suite 330, Boston, MA  02111-1307  USA.


        ***************************************************************************
        *                                                                         *
        * Looking for a quick start?  Then check out the FreeRTOS eBook!          *
        * See http://www.FreeRTOS.org/Documentation for details                   *
        *                                                                         *
        ***************************************************************************

        1 tab == 4 spaces!

        Please ensure to read the configuration and relevant port sections of the
        online documentation.

        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.

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*/

/*
 * This is a version of BlockTim.c that uses the light weight API.
 *
 * This file contains some test scenarios that ensure tasks do not exit queue
 * send or receive functions prematurely.  A description of the tests is
 * included within the code.
 */

/* Kernel includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

/* Demo includes. */
#include "AltBlock.h"

/* Task priorities. */
#define bktPRIMARY_PRIORITY                     ( 3 )
#define bktSECONDARY_PRIORITY           ( 2 )

/* Task behaviour. */
#define bktQUEUE_LENGTH                         ( 5 )
#define bktSHORT_WAIT                           ( ( ( portTickType ) 20 ) / portTICK_RATE_MS )
#define bktPRIMARY_BLOCK_TIME           ( 10 )
#define bktALLOWABLE_MARGIN                     ( 12 )
#define bktTIME_TO_BLOCK                        ( 175 )
#define bktDONT_BLOCK                           ( ( portTickType ) 0 )
#define bktRUN_INDICATOR                        ( ( unsigned portBASE_TYPE ) 0x55 )

/* The queue on which the tasks block. */
static xQueueHandle xTestQueue;

/* Handle to the secondary task is required by the primary task for calls
to vTaskSuspend/Resume(). */
static xTaskHandle xSecondary;

/* Used to ensure that tasks are still executing without error. */
static portBASE_TYPE xPrimaryCycles = 0, xSecondaryCycles = 0;
static portBASE_TYPE xErrorOccurred = pdFALSE;

/* Provides a simple mechanism for the primary task to know when the
secondary task has executed. */
static volatile unsigned portBASE_TYPE xRunIndicator;

/* The two test tasks.  Their behaviour is commented within the files. */
static void vPrimaryBlockTimeTestTask( void *pvParameters );
static void vSecondaryBlockTimeTestTask( void *pvParameters );

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

void vCreateAltBlockTimeTasks( void )
{
        /* Create the queue on which the two tasks block. */
    xTestQueue = xQueueCreate( bktQUEUE_LENGTH, sizeof( portBASE_TYPE ) );

        /* vQueueAddToRegistry() adds the queue to the queue registry, if one is
        in use.  The queue registry is provided as a means for kernel aware 
        debuggers to locate queues 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( xTestQueue, ( signed portCHAR * ) "AltBlockQueue" );


        /* Create the two test tasks. */
        xTaskCreate( vPrimaryBlockTimeTestTask, ( signed portCHAR * )"FBTest1", configMINIMAL_STACK_SIZE, NULL, bktPRIMARY_PRIORITY, NULL );
        xTaskCreate( vSecondaryBlockTimeTestTask, ( signed portCHAR * )"FBTest2", configMINIMAL_STACK_SIZE, NULL, bktSECONDARY_PRIORITY, &xSecondary );
}
/*-----------------------------------------------------------*/

static void vPrimaryBlockTimeTestTask( void *pvParameters )
{
portBASE_TYPE xItem, xData;
portTickType xTimeWhenBlocking;
portTickType xTimeToBlock, xBlockedTime;

        #ifdef USE_STDIO
        void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
        
                const portCHAR * const pcTaskStartMsg = "Alt primary block time test started.\r\n";

                /* Queue a message for printing to say the task has started. */
                vPrintDisplayMessage( &pcTaskStartMsg );
        #endif

        ( void ) pvParameters;

        for( ;; )
        {
                /*********************************************************************
        Test 1

        Simple block time wakeup test on queue receives. */
                for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
                {
                        /* The queue is empty. Attempt to read from the queue using a block
                        time.  When we wake, ensure the delta in time is as expected. */
                        xTimeToBlock = bktPRIMARY_BLOCK_TIME << xItem;

                        /* A critical section is used to minimise the jitter in the time
                        measurements. */
                        portENTER_CRITICAL();
                        {
                                xTimeWhenBlocking = xTaskGetTickCount();
                                
                                /* We should unblock after xTimeToBlock having not received
                                anything on the queue. */
                                if( xQueueAltReceive( xTestQueue, &xData, xTimeToBlock ) != errQUEUE_EMPTY )
                                {
                                        xErrorOccurred = pdTRUE;
                                }

                                /* How long were we blocked for? */
                                xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
                        }
                        portEXIT_CRITICAL();

                        if( xBlockedTime < xTimeToBlock )
                        {
                                /* Should not have blocked for less than we requested. */
                                xErrorOccurred = pdTRUE;
                        }

                        if( xBlockedTime > ( xTimeToBlock + bktALLOWABLE_MARGIN ) )
                        {
                                /* Should not have blocked for longer than we requested,
                                although we would not necessarily run as soon as we were
                                unblocked so a margin is allowed. */
                                xErrorOccurred = pdTRUE;
                        }
                }


                #if configUSE_PREEMPTION == 0
                        taskYIELD();
                #endif


                /*********************************************************************
        Test 2

        Simple block time wakeup test on queue sends.

                First fill the queue.  It should be empty so all sends should pass. */
                for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
                {
                        if( xQueueAltSendToBack( xTestQueue, &xItem, bktDONT_BLOCK ) != pdPASS )
                        {
                                xErrorOccurred = pdTRUE;
                        }
                }

                for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
                {
                        /* The queue is full. Attempt to write to the queue using a block
                        time.  When we wake, ensure the delta in time is as expected. */
                        xTimeToBlock = bktPRIMARY_BLOCK_TIME << xItem;

                        portENTER_CRITICAL();
                        {
                                xTimeWhenBlocking = xTaskGetTickCount();
                                
                                /* We should unblock after xTimeToBlock having not received
                                anything on the queue. */
                                if( xQueueAltSendToBack( xTestQueue, &xItem, xTimeToBlock ) != errQUEUE_FULL )
                                {
                                        xErrorOccurred = pdTRUE;
                                }

                                /* How long were we blocked for? */
                                xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
                        }
                        portEXIT_CRITICAL();

                        if( xBlockedTime < xTimeToBlock )
                        {
                                /* Should not have blocked for less than we requested. */
                                xErrorOccurred = pdTRUE;
                        }

                        if( xBlockedTime > ( xTimeToBlock + bktALLOWABLE_MARGIN ) )
                        {
                                /* Should not have blocked for longer than we requested,
                                although we would not necessarily run as soon as we were
                                unblocked so a margin is allowed. */
                                xErrorOccurred = pdTRUE;
                        }
                }

                #if configUSE_PREEMPTION == 0
                        taskYIELD();
                #endif

                
                /*********************************************************************
        Test 3

                Wake the other task, it will block attempting to post to the queue.
                When we read from the queue the other task will wake, but before it
                can run we will post to the queue again.  When the other task runs it
                will find the queue still full, even though it was woken.  It should
                recognise that its block time has not expired and return to block for
                the remains of its block time.

                Wake the other task so it blocks attempting to post to the already
                full queue. */
                xRunIndicator = 0;
                vTaskResume( xSecondary );

                /* We need to wait a little to ensure the other task executes. */
                while( xRunIndicator != bktRUN_INDICATOR )
                {
                        /* The other task has not yet executed. */
                        vTaskDelay( bktSHORT_WAIT );
                }
                /* Make sure the other task is blocked on the queue. */
                vTaskDelay( bktSHORT_WAIT );
                xRunIndicator = 0;

                for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
                {
                        /* Now when we make space on the queue the other task should wake
                        but not execute as this task has higher priority. */                            
                        if( xQueueAltReceive( xTestQueue, &xData, bktDONT_BLOCK ) != pdPASS )
                        {
                                xErrorOccurred = pdTRUE;
                        }

                        /* Now fill the queue again before the other task gets a chance to
                        execute.  If the other task had executed we would find the queue
                        full ourselves, and the other task have set xRunIndicator. */
                        if( xQueueAltSendToBack( xTestQueue, &xItem, bktDONT_BLOCK ) != pdPASS )
                        {
                                xErrorOccurred = pdTRUE;
                        }

                        if( xRunIndicator == bktRUN_INDICATOR )
                        {
                                /* The other task should not have executed. */
                                xErrorOccurred = pdTRUE;
                        }

                        /* Raise the priority of the other task so it executes and blocks
                        on the queue again. */
                        vTaskPrioritySet( xSecondary, bktPRIMARY_PRIORITY + 2 );

                        /* The other task should now have re-blocked without exiting the
                        queue function. */
                        if( xRunIndicator == bktRUN_INDICATOR )
                        {
                                /* The other task should not have executed outside of the
                                queue function. */
                                xErrorOccurred = pdTRUE;
                        }

                        /* Set the priority back down. */
                        vTaskPrioritySet( xSecondary, bktSECONDARY_PRIORITY );                  
                }

                /* Let the other task timeout.  When it unblockes it will check that it
                unblocked at the correct time, then suspend itself. */
                while( xRunIndicator != bktRUN_INDICATOR )
                {
                        vTaskDelay( bktSHORT_WAIT );
                }
                vTaskDelay( bktSHORT_WAIT );
                xRunIndicator = 0;

                #if configUSE_PREEMPTION == 0
                        taskYIELD();
                #endif

                /*********************************************************************
        Test 4

                As per test 3 - but with the send and receive the other way around.
                The other task blocks attempting to read from the queue.

                Empty the queue.  We should find that it is full. */
                for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
                {
                        if( xQueueAltReceive( xTestQueue, &xData, bktDONT_BLOCK ) != pdPASS )
                        {
                                xErrorOccurred = pdTRUE;
                        }
                }
                
                /* Wake the other task so it blocks attempting to read from  the
                already empty queue. */
                vTaskResume( xSecondary );

                /* We need to wait a little to ensure the other task executes. */
                while( xRunIndicator != bktRUN_INDICATOR )
                {
                        vTaskDelay( bktSHORT_WAIT );
                }
                vTaskDelay( bktSHORT_WAIT );
                xRunIndicator = 0;

                for( xItem = 0; xItem < bktQUEUE_LENGTH; xItem++ )
                {
                        /* Now when we place an item on the queue the other task should
                        wake but not execute as this task has higher priority. */                               
                        if( xQueueAltSendToBack( xTestQueue, &xItem, bktDONT_BLOCK ) != pdPASS )
                        {
                                xErrorOccurred = pdTRUE;
                        }

                        /* Now empty the queue again before the other task gets a chance to
                        execute.  If the other task had executed we would find the queue
                        empty ourselves, and the other task would be suspended. */
                        if( xQueueAltReceive( xTestQueue, &xData, bktDONT_BLOCK ) != pdPASS )
                        {
                                xErrorOccurred = pdTRUE;
                        }

                        if( xRunIndicator == bktRUN_INDICATOR )
                        {
                                /* The other task should not have executed. */
                                xErrorOccurred = pdTRUE;
                        }

                        /* Raise the priority of the other task so it executes and blocks
                        on the queue again. */
                        vTaskPrioritySet( xSecondary, bktPRIMARY_PRIORITY + 2 );

                        /* The other task should now have re-blocked without exiting the
                        queue function. */
                        if( xRunIndicator == bktRUN_INDICATOR )
                        {
                                /* The other task should not have executed outside of the
                                queue function. */
                                xErrorOccurred = pdTRUE;
                        }
                        vTaskPrioritySet( xSecondary, bktSECONDARY_PRIORITY );                  
                }

                /* Let the other task timeout.  When it unblockes it will check that it
                unblocked at the correct time, then suspend itself. */
                while( xRunIndicator != bktRUN_INDICATOR )
                {
                        vTaskDelay( bktSHORT_WAIT );
                }
                vTaskDelay( bktSHORT_WAIT );

                xPrimaryCycles++;
        }
}
/*-----------------------------------------------------------*/

static void vSecondaryBlockTimeTestTask( void *pvParameters )
{
portTickType xTimeWhenBlocking, xBlockedTime;
portBASE_TYPE xData;

        #ifdef USE_STDIO
        void vPrintDisplayMessage( const portCHAR * const * ppcMessageToSend );
        
                const portCHAR * const pcTaskStartMsg = "Alt secondary block time test started.\r\n";

                /* Queue a message for printing to say the task has started. */
                vPrintDisplayMessage( &pcTaskStartMsg );
        #endif

        ( void ) pvParameters;

        for( ;; )
        {
                /*********************************************************************
        Test 1 and 2

                This task does does not participate in these tests. */
                vTaskSuspend( NULL );

                /*********************************************************************
        Test 3

                The first thing we do is attempt to read from the queue.  It should be
                full so we block.  Note the time before we block so we can check the
                wake time is as per that expected. */
                portENTER_CRITICAL();
                {
                        xTimeWhenBlocking = xTaskGetTickCount();
                        
                        /* We should unblock after bktTIME_TO_BLOCK having not received
                        anything on the queue. */
                        xData = 0;
                        xRunIndicator = bktRUN_INDICATOR;
                        if( xQueueAltSendToBack( xTestQueue, &xData, bktTIME_TO_BLOCK ) != errQUEUE_FULL )
                        {
                                xErrorOccurred = pdTRUE;
                        }

                        /* How long were we inside the send function? */
                        xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
                }
                portEXIT_CRITICAL();

                /* We should not have blocked for less time than bktTIME_TO_BLOCK. */
                if( xBlockedTime < bktTIME_TO_BLOCK )
                {
                        xErrorOccurred = pdTRUE;
                }

                /* We should of not blocked for much longer than bktALLOWABLE_MARGIN
                either.  A margin is permitted as we would not necessarily run as
                soon as we unblocked. */
                if( xBlockedTime > ( bktTIME_TO_BLOCK + bktALLOWABLE_MARGIN ) )
                {
                        xErrorOccurred = pdTRUE;
                }

                /* Suspend ready for test 3. */
                xRunIndicator = bktRUN_INDICATOR;
                vTaskSuspend( NULL );

                /*********************************************************************
        Test 4

                As per test three, but with the send and receive reversed. */
                portENTER_CRITICAL();
                {
                        xTimeWhenBlocking = xTaskGetTickCount();
                        
                        /* We should unblock after bktTIME_TO_BLOCK having not received
                        anything on the queue. */
                        xRunIndicator = bktRUN_INDICATOR;
                        if( xQueueAltReceive( xTestQueue, &xData, bktTIME_TO_BLOCK ) != errQUEUE_EMPTY )
                        {
                                xErrorOccurred = pdTRUE;
                        }

                        xBlockedTime = xTaskGetTickCount() - xTimeWhenBlocking;
                }
                portEXIT_CRITICAL();

                /* We should not have blocked for less time than bktTIME_TO_BLOCK. */
                if( xBlockedTime < bktTIME_TO_BLOCK )
                {
                        xErrorOccurred = pdTRUE;
                }

                /* We should of not blocked for much longer than bktALLOWABLE_MARGIN
                either.  A margin is permitted as we would not necessarily run as soon
                as we unblocked. */
                if( xBlockedTime > ( bktTIME_TO_BLOCK + bktALLOWABLE_MARGIN ) )
                {
                        xErrorOccurred = pdTRUE;
                }

                xRunIndicator = bktRUN_INDICATOR;

                xSecondaryCycles++;
        }
}
/*-----------------------------------------------------------*/

portBASE_TYPE xAreAltBlockTimeTestTasksStillRunning( void )
{
static portBASE_TYPE xLastPrimaryCycleCount = 0, xLastSecondaryCycleCount = 0;
portBASE_TYPE xReturn = pdPASS;

        /* Have both tasks performed at least one cycle since this function was
        last called? */
        if( xPrimaryCycles == xLastPrimaryCycleCount )
        {
                xReturn = pdFAIL;
        }

        if( xSecondaryCycles == xLastSecondaryCycleCount )
        {
                xReturn = pdFAIL;
        }

        if( xErrorOccurred == pdTRUE )
        {
                xReturn = pdFAIL;
        }

        xLastSecondaryCycleCount = xSecondaryCycles;
        xLastPrimaryCycleCount = xPrimaryCycles;

        return xReturn;
}