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/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
#include "FreeRTOS.h"
#include "task.h"
#include "croutine.h"
/* Remove the whole file if co-routines are not being used. */
#if ( configUSE_CO_ROUTINES != 0 )
/*
* Some kernel aware debuggers require data to be viewed to be global, rather
* than file scope.
*/
#ifdef portREMOVE_STATIC_QUALIFIER
#define static
#endif
/* Lists for ready and blocked co-routines. --------------------*/
static List_t pxReadyCoRoutineLists[ configMAX_CO_ROUTINE_PRIORITIES ]; /**< Prioritised ready co-routines. */
static List_t xDelayedCoRoutineList1; /**< Delayed co-routines. */
static List_t xDelayedCoRoutineList2; /**< Delayed co-routines (two lists are used - one for delays that have overflowed the current tick count. */
static List_t * pxDelayedCoRoutineList = NULL; /**< Points to the delayed co-routine list currently being used. */
static List_t * pxOverflowDelayedCoRoutineList = NULL; /**< Points to the delayed co-routine list currently being used to hold co-routines that have overflowed the current tick count. */
static List_t xPendingReadyCoRoutineList; /**< Holds co-routines that have been readied by an external event. They cannot be added directly to the ready lists as the ready lists cannot be accessed by interrupts. */
/* Other file private variables. --------------------------------*/
CRCB_t * pxCurrentCoRoutine = NULL;
static UBaseType_t uxTopCoRoutineReadyPriority = ( UBaseType_t ) 0U;
static TickType_t xCoRoutineTickCount = ( TickType_t ) 0U;
static TickType_t xLastTickCount = ( TickType_t ) 0U;
static TickType_t xPassedTicks = ( TickType_t ) 0U;
/* The initial state of the co-routine when it is created. */
#define corINITIAL_STATE ( 0 )
/*
* Place the co-routine represented by pxCRCB into the appropriate ready queue
* for the priority. It is inserted at the end of the list.
*
* This macro accesses the co-routine ready lists and therefore must not be
* used from within an ISR.
*/
#define prvAddCoRoutineToReadyQueue( pxCRCB ) \
do { \
if( ( pxCRCB )->uxPriority > uxTopCoRoutineReadyPriority ) \
{ \
uxTopCoRoutineReadyPriority = ( pxCRCB )->uxPriority; \
} \
vListInsertEnd( ( List_t * ) &( pxReadyCoRoutineLists[ ( pxCRCB )->uxPriority ] ), &( ( pxCRCB )->xGenericListItem ) ); \
} while( 0 )
/*
* Utility to ready all the lists used by the scheduler. This is called
* automatically upon the creation of the first co-routine.
*/
static void prvInitialiseCoRoutineLists( void );
/*
* Co-routines that are readied by an interrupt cannot be placed directly into
* the ready lists (there is no mutual exclusion). Instead they are placed in
* in the pending ready list in order that they can later be moved to the ready
* list by the co-routine scheduler.
*/
static void prvCheckPendingReadyList( void );
/*
* Macro that looks at the list of co-routines that are currently delayed to
* see if any require waking.
*
* Co-routines are stored in the queue in the order of their wake time -
* meaning once one co-routine has been found whose timer has not expired
* we need not look any further down the list.
*/
static void prvCheckDelayedList( void );
/*-----------------------------------------------------------*/
BaseType_t xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode,
UBaseType_t uxPriority,
UBaseType_t uxIndex )
{
BaseType_t xReturn;
CRCB_t * pxCoRoutine;
traceENTER_xCoRoutineCreate( pxCoRoutineCode, uxPriority, uxIndex );
/* Allocate the memory that will store the co-routine control block. */
/* MISRA Ref 11.5.1 [Malloc memory assignment] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-115 */
/* coverity[misra_c_2012_rule_11_5_violation] */
pxCoRoutine = ( CRCB_t * ) pvPortMalloc( sizeof( CRCB_t ) );
if( pxCoRoutine )
{
/* If pxCurrentCoRoutine is NULL then this is the first co-routine to
* be created and the co-routine data structures need initialising. */
if( pxCurrentCoRoutine == NULL )
{
pxCurrentCoRoutine = pxCoRoutine;
prvInitialiseCoRoutineLists();
}
/* Check the priority is within limits. */
if( uxPriority >= configMAX_CO_ROUTINE_PRIORITIES )
{
uxPriority = configMAX_CO_ROUTINE_PRIORITIES - 1;
}
/* Fill out the co-routine control block from the function parameters. */
pxCoRoutine->uxState = corINITIAL_STATE;
pxCoRoutine->uxPriority = uxPriority;
pxCoRoutine->uxIndex = uxIndex;
pxCoRoutine->pxCoRoutineFunction = pxCoRoutineCode;
/* Initialise all the other co-routine control block parameters. */
vListInitialiseItem( &( pxCoRoutine->xGenericListItem ) );
vListInitialiseItem( &( pxCoRoutine->xEventListItem ) );
/* Set the co-routine control block as a link back from the ListItem_t.
* This is so we can get back to the containing CRCB from a generic item
* in a list. */
listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xGenericListItem ), pxCoRoutine );
listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xEventListItem ), pxCoRoutine );
/* Event lists are always in priority order. */
listSET_LIST_ITEM_VALUE( &( pxCoRoutine->xEventListItem ), ( ( TickType_t ) configMAX_CO_ROUTINE_PRIORITIES - ( TickType_t ) uxPriority ) );
/* Now the co-routine has been initialised it can be added to the ready
* list at the correct priority. */
prvAddCoRoutineToReadyQueue( pxCoRoutine );
xReturn = pdPASS;
}
else
{
xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
}
traceRETURN_xCoRoutineCreate( xReturn );
return xReturn;
}
/*-----------------------------------------------------------*/
void vCoRoutineAddToDelayedList( TickType_t xTicksToDelay,
List_t * pxEventList )
{
TickType_t xTimeToWake;
traceENTER_vCoRoutineAddToDelayedList( xTicksToDelay, pxEventList );
/* Calculate the time to wake - this may overflow but this is
* not a problem. */
xTimeToWake = xCoRoutineTickCount + xTicksToDelay;
/* We must remove ourselves from the ready list before adding
* ourselves to the blocked list as the same list item is used for
* both lists. */
( void ) uxListRemove( ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
/* The list item will be inserted in wake time order. */
listSET_LIST_ITEM_VALUE( &( pxCurrentCoRoutine->xGenericListItem ), xTimeToWake );
if( xTimeToWake < xCoRoutineTickCount )
{
/* Wake time has overflowed. Place this item in the
* overflow list. */
vListInsert( ( List_t * ) pxOverflowDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
}
else
{
/* The wake time has not overflowed, so we can use the
* current block list. */
vListInsert( ( List_t * ) pxDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
}
if( pxEventList )
{
/* Also add the co-routine to an event list. If this is done then the
* function must be called with interrupts disabled. */
vListInsert( pxEventList, &( pxCurrentCoRoutine->xEventListItem ) );
}
traceRETURN_vCoRoutineAddToDelayedList();
}
/*-----------------------------------------------------------*/
static void prvCheckPendingReadyList( void )
{
/* Are there any co-routines waiting to get moved to the ready list? These
* are co-routines that have been readied by an ISR. The ISR cannot access
* the ready lists itself. */
while( listLIST_IS_EMPTY( &xPendingReadyCoRoutineList ) == pdFALSE )
{
CRCB_t * pxUnblockedCRCB;
/* The pending ready list can be accessed by an ISR. */
portDISABLE_INTERRUPTS();
{
pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( ( &xPendingReadyCoRoutineList ) );
( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) );
}
portENABLE_INTERRUPTS();
( void ) uxListRemove( &( pxUnblockedCRCB->xGenericListItem ) );
prvAddCoRoutineToReadyQueue( pxUnblockedCRCB );
}
}
/*-----------------------------------------------------------*/
static void prvCheckDelayedList( void )
{
CRCB_t * pxCRCB;
xPassedTicks = xTaskGetTickCount() - xLastTickCount;
while( xPassedTicks )
{
xCoRoutineTickCount++;
xPassedTicks--;
/* If the tick count has overflowed we need to swap the ready lists. */
if( xCoRoutineTickCount == 0 )
{
List_t * pxTemp;
/* Tick count has overflowed so we need to swap the delay lists. If there are
* any items in pxDelayedCoRoutineList here then there is an error! */
pxTemp = pxDelayedCoRoutineList;
pxDelayedCoRoutineList = pxOverflowDelayedCoRoutineList;
pxOverflowDelayedCoRoutineList = pxTemp;
}
/* See if this tick has made a timeout expire. */
while( listLIST_IS_EMPTY( pxDelayedCoRoutineList ) == pdFALSE )
{
pxCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedCoRoutineList );
if( xCoRoutineTickCount < listGET_LIST_ITEM_VALUE( &( pxCRCB->xGenericListItem ) ) )
{
/* Timeout not yet expired. */
break;
}
portDISABLE_INTERRUPTS();
{
/* The event could have occurred just before this critical
* section. If this is the case then the generic list item will
* have been moved to the pending ready list and the following
* line is still valid. Also the pvContainer parameter will have
* been set to NULL so the following lines are also valid. */
( void ) uxListRemove( &( pxCRCB->xGenericListItem ) );
/* Is the co-routine waiting on an event also? */
if( pxCRCB->xEventListItem.pxContainer )
{
( void ) uxListRemove( &( pxCRCB->xEventListItem ) );
}
}
portENABLE_INTERRUPTS();
prvAddCoRoutineToReadyQueue( pxCRCB );
}
}
xLastTickCount = xCoRoutineTickCount;
}
/*-----------------------------------------------------------*/
void vCoRoutineSchedule( void )
{
traceENTER_vCoRoutineSchedule();
/* Only run a co-routine after prvInitialiseCoRoutineLists() has been
* called. prvInitialiseCoRoutineLists() is called automatically when a
* co-routine is created. */
if( pxDelayedCoRoutineList != NULL )
{
/* See if any co-routines readied by events need moving to the ready lists. */
prvCheckPendingReadyList();
/* See if any delayed co-routines have timed out. */
prvCheckDelayedList();
/* Find the highest priority queue that contains ready co-routines. */
while( listLIST_IS_EMPTY( &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) ) )
{
if( uxTopCoRoutineReadyPriority == 0 )
{
/* No more co-routines to check. */
return;
}
--uxTopCoRoutineReadyPriority;
}
/* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the co-routines
* of the same priority get an equal share of the processor time. */
listGET_OWNER_OF_NEXT_ENTRY( pxCurrentCoRoutine, &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) );
/* Call the co-routine. */
( pxCurrentCoRoutine->pxCoRoutineFunction )( pxCurrentCoRoutine, pxCurrentCoRoutine->uxIndex );
}
traceRETURN_vCoRoutineSchedule();
}
/*-----------------------------------------------------------*/
static void prvInitialiseCoRoutineLists( void )
{
UBaseType_t uxPriority;
for( uxPriority = 0; uxPriority < configMAX_CO_ROUTINE_PRIORITIES; uxPriority++ )
{
vListInitialise( ( List_t * ) &( pxReadyCoRoutineLists[ uxPriority ] ) );
}
vListInitialise( ( List_t * ) &xDelayedCoRoutineList1 );
vListInitialise( ( List_t * ) &xDelayedCoRoutineList2 );
vListInitialise( ( List_t * ) &xPendingReadyCoRoutineList );
/* Start with pxDelayedCoRoutineList using list1 and the
* pxOverflowDelayedCoRoutineList using list2. */
pxDelayedCoRoutineList = &xDelayedCoRoutineList1;
pxOverflowDelayedCoRoutineList = &xDelayedCoRoutineList2;
}
/*-----------------------------------------------------------*/
BaseType_t xCoRoutineRemoveFromEventList( const List_t * pxEventList )
{
CRCB_t * pxUnblockedCRCB;
BaseType_t xReturn;
traceENTER_xCoRoutineRemoveFromEventList( pxEventList );
/* This function is called from within an interrupt. It can only access
* event lists and the pending ready list. This function assumes that a
* check has already been made to ensure pxEventList is not empty. */
pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) );
vListInsertEnd( ( List_t * ) &( xPendingReadyCoRoutineList ), &( pxUnblockedCRCB->xEventListItem ) );
if( pxUnblockedCRCB->uxPriority >= pxCurrentCoRoutine->uxPriority )
{
xReturn = pdTRUE;
}
else
{
xReturn = pdFALSE;
}
traceRETURN_xCoRoutineRemoveFromEventList( xReturn );
return xReturn;
}
/*-----------------------------------------------------------*/
/*
* Reset state in this file. This state is normally initialized at start up.
* This function must be called by the application before restarting the
* scheduler.
*/
void vCoRoutineResetState( void )
{
/* Lists for ready and blocked co-routines. */
pxDelayedCoRoutineList = NULL;
pxOverflowDelayedCoRoutineList = NULL;
/* Other file private variables. */
pxCurrentCoRoutine = NULL;
uxTopCoRoutineReadyPriority = ( UBaseType_t ) 0U;
xCoRoutineTickCount = ( TickType_t ) 0U;
xLastTickCount = ( TickType_t ) 0U;
xPassedTicks = ( TickType_t ) 0U;
}
/*-----------------------------------------------------------*/
#endif /* configUSE_CO_ROUTINES == 0 */
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