2 * FreeRTOS Kernel V10.3.0
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3 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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29 * This version of PollQ. c is for use on systems that have limited stack
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30 * space and no display facilities. The complete version can be found in
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31 * the Demo/Common/Full directory.
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33 * Creates two tasks that communicate over a single queue. One task acts as a
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34 * producer, the other a consumer.
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36 * The producer loops for three iteration, posting an incrementing number onto the
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37 * queue each cycle. It then delays for a fixed period before doing exactly the
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40 * The consumer loops emptying the queue. Each item removed from the queue is
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41 * checked to ensure it contains the expected value. When the queue is empty it
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42 * blocks for a fixed period, then does the same again.
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44 * All queue access is performed without blocking. The consumer completely empties
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45 * the queue each time it runs so the producer should never find the queue full.
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47 * An error is flagged if the consumer obtains an unexpected value or the producer
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48 * find the queue is full.
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54 + Delay periods are now specified using variables and constants of
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55 TickType_t rather than uint32_t.
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60 /* Scheduler include files. */
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61 #include "FreeRTOS.h"
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65 /* Demo program include files. */
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68 #define pollqSTACK_SIZE configMINIMAL_STACK_SIZE
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69 #define pollqQUEUE_SIZE ( 10 )
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70 #define pollqPRODUCER_DELAY ( pdMS_TO_TICKS( ( TickType_t ) 200 ) )
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71 #define pollqCONSUMER_DELAY ( pollqPRODUCER_DELAY - ( TickType_t ) ( 20 / portTICK_PERIOD_MS ) )
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72 #define pollqNO_DELAY ( ( TickType_t ) 0 )
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73 #define pollqVALUES_TO_PRODUCE ( ( BaseType_t ) 3 )
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74 #define pollqINITIAL_VALUE ( ( BaseType_t ) 0 )
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76 /* The task that posts the incrementing number onto the queue. */
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77 static portTASK_FUNCTION_PROTO( vPolledQueueProducer, pvParameters );
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79 /* The task that empties the queue. */
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80 static portTASK_FUNCTION_PROTO( vPolledQueueConsumer, pvParameters );
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82 /* Variables that are used to check that the tasks are still running with no
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84 static volatile BaseType_t xPollingConsumerCount = pollqINITIAL_VALUE, xPollingProducerCount = pollqINITIAL_VALUE;
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86 /*-----------------------------------------------------------*/
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88 void vStartPolledQueueTasks( UBaseType_t uxPriority )
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90 static QueueHandle_t xPolledQueue;
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92 /* Create the queue used by the producer and consumer. */
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93 xPolledQueue = xQueueCreate( pollqQUEUE_SIZE, ( UBaseType_t ) sizeof( uint16_t ) );
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95 if( xPolledQueue != NULL )
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97 /* vQueueAddToRegistry() adds the queue to the queue registry, if one is
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98 in use. The queue registry is provided as a means for kernel aware
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99 debuggers to locate queues and has no purpose if a kernel aware debugger
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100 is not being used. The call to vQueueAddToRegistry() will be removed
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101 by the pre-processor if configQUEUE_REGISTRY_SIZE is not defined or is
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102 defined to be less than 1. */
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103 vQueueAddToRegistry( xPolledQueue, "Poll_Test_Queue" );
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105 /* Spawn the producer and consumer. */
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106 xTaskCreate( vPolledQueueConsumer, "QConsNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( TaskHandle_t * ) NULL );
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107 xTaskCreate( vPolledQueueProducer, "QProdNB", pollqSTACK_SIZE, ( void * ) &xPolledQueue, uxPriority, ( TaskHandle_t * ) NULL );
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110 /*-----------------------------------------------------------*/
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112 static portTASK_FUNCTION( vPolledQueueProducer, pvParameters )
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114 uint16_t usValue = ( uint16_t ) 0;
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115 BaseType_t xError = pdFALSE, xLoop;
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119 for( xLoop = 0; xLoop < pollqVALUES_TO_PRODUCE; xLoop++ )
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121 /* Send an incrementing number on the queue without blocking. */
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122 if( xQueueSend( *( ( QueueHandle_t * ) pvParameters ), ( void * ) &usValue, pollqNO_DELAY ) != pdPASS )
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124 /* We should never find the queue full so if we get here there
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125 has been an error. */
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130 if( xError == pdFALSE )
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132 /* If an error has ever been recorded we stop incrementing the
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134 portENTER_CRITICAL();
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135 xPollingProducerCount++;
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136 portEXIT_CRITICAL();
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139 /* Update the value we are going to post next time around. */
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144 /* Wait before we start posting again to ensure the consumer runs and
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145 empties the queue. */
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146 vTaskDelay( pollqPRODUCER_DELAY );
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148 } /*lint !e818 Function prototype must conform to API. */
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149 /*-----------------------------------------------------------*/
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151 static portTASK_FUNCTION( vPolledQueueConsumer, pvParameters )
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153 uint16_t usData, usExpectedValue = ( uint16_t ) 0;
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154 BaseType_t xError = pdFALSE;
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158 /* Loop until the queue is empty. */
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159 while( uxQueueMessagesWaiting( *( ( QueueHandle_t * ) pvParameters ) ) )
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161 if( xQueueReceive( *( ( QueueHandle_t * ) pvParameters ), &usData, pollqNO_DELAY ) == pdPASS )
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163 if( usData != usExpectedValue )
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165 /* This is not what we expected to receive so an error has
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169 /* Catch-up to the value we received so our next expected
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170 value should again be correct. */
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171 usExpectedValue = usData;
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175 if( xError == pdFALSE )
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177 /* Only increment the check variable if no errors have
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179 portENTER_CRITICAL();
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180 xPollingConsumerCount++;
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181 portEXIT_CRITICAL();
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185 /* Next time round we would expect the number to be one higher. */
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190 /* Now the queue is empty we block, allowing the producer to place more
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191 items in the queue. */
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192 vTaskDelay( pollqCONSUMER_DELAY );
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194 } /*lint !e818 Function prototype must conform to API. */
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195 /*-----------------------------------------------------------*/
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197 /* This is called to check that all the created tasks are still running with no errors. */
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198 BaseType_t xArePollingQueuesStillRunning( void )
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200 BaseType_t xReturn;
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202 /* Check both the consumer and producer poll count to check they have both
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203 been changed since out last trip round. We do not need a critical section
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204 around the check variables as this is called from a higher priority than
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205 the other tasks that access the same variables. */
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206 if( ( xPollingConsumerCount == pollqINITIAL_VALUE ) ||
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207 ( xPollingProducerCount == pollqINITIAL_VALUE )
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217 /* Set the check variables back down so we know if they have been
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218 incremented the next time around. */
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219 xPollingConsumerCount = pollqINITIAL_VALUE;
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220 xPollingProducerCount = pollqINITIAL_VALUE;
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