284 lines
9.4 KiB
C
284 lines
9.4 KiB
C
/*
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* FreeRTOS Kernel V10.3.0
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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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 BaseType_t 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(SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t *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(SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t *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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/* The semaphore to be used for the demo. */
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SemaphoreHandle_t 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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UBaseType_t 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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volatile UBaseType_t 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 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(
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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 =
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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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/* Were the semaphores created? */
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if ((xParameters[0].xSemaphore != NULL) ||
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(xParameters[1].xSemaphore != NULL)) {
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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
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debugger is not being used. The call to vQueueAddToRegistry() will be
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removed by the pre-processor if configQUEUE_REGISTRY_SIZE is not
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defined or is defined to be less than 1. */
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vQueueAddToRegistry((QueueHandle_t)xParameters[0].xSemaphore,
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"Counting_Sem_1");
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vQueueAddToRegistry((QueueHandle_t)xParameters[1].xSemaphore,
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"Counting_Sem_2");
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/* Create the demo tasks, passing in the semaphore to use as the parameter. */
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xTaskCreate(prvCountingSemaphoreTask, "CNT1",
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configMINIMAL_STACK_SIZE, (void *)&(xParameters[0]),
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tskIDLE_PRIORITY, NULL);
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xTaskCreate(prvCountingSemaphoreTask, "CNT2",
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configMINIMAL_STACK_SIZE, (void *)&(xParameters[1]),
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tskIDLE_PRIORITY, NULL);
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}
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}
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/*-----------------------------------------------------------*/
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static void prvDecrementSemaphoreCount(SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t *puxLoopCounter)
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{
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UBaseType_t 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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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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configASSERT(uxSemaphoreGetCount(xSemaphore) ==
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(countMAX_COUNT_VALUE - ux));
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if (xSemaphoreTake(xSemaphore, countDONT_BLOCK) != pdPASS) {
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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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configASSERT(uxSemaphoreGetCount(xSemaphore) == 0);
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if (xSemaphoreTake(xSemaphore, countDONT_BLOCK) == pdPASS) {
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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(SemaphoreHandle_t xSemaphore,
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volatile UBaseType_t *puxLoopCounter)
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{
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UBaseType_t 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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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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configASSERT(uxSemaphoreGetCount(xSemaphore) == ux);
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if (xSemaphoreGive(xSemaphore) != pdPASS) {
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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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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 char *const *ppcMessageToSend);
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const char *const pcTaskStartMsg =
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"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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prvDecrementSemaphoreCount(pxParameter->xSemaphore,
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&(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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xErrorDetected = pdTRUE;
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}
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for (;;) {
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prvIncrementSemaphoreCount(pxParameter->xSemaphore,
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&(pxParameter->uxLoopCounter));
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prvDecrementSemaphoreCount(pxParameter->xSemaphore,
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&(pxParameter->uxLoopCounter));
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}
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}
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/*-----------------------------------------------------------*/
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BaseType_t xAreCountingSemaphoreTasksStillRunning(void)
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{
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static UBaseType_t uxLastCount0 = 0, uxLastCount1 = 0;
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BaseType_t 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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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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xReturn = pdFAIL;
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} else {
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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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xReturn = pdFAIL;
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} else {
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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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