begriffs open source - cmsis-freertos/blob - Source/croutine.c

   1 /*
   2     FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
   3     All rights reserved
   4
   5     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
   6
   7     This file is part of the FreeRTOS distribution.
   8
   9     FreeRTOS is free software; you can redistribute it and/or modify it under
  10     the terms of the GNU General Public License (version 2) as published by the
  11     Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
  12
  13     ***************************************************************************
  14     >>!   NOTE: The modification to the GPL is included to allow you to     !<<
  15     >>!   distribute a combined work that includes FreeRTOS without being   !<<
  16     >>!   obliged to provide the source code for proprietary components     !<<
  17     >>!   outside of the FreeRTOS kernel.                                   !<<
  18     ***************************************************************************
  19
  20     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
  21     WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  22     FOR A PARTICULAR PURPOSE.  Full license text is available on the following
  23     link: http://www.freertos.org/a00114.html
  24
  25     ***************************************************************************
  26      *                                                                       *
  27      *    FreeRTOS provides completely free yet professionally developed,    *
  28      *    robust, strictly quality controlled, supported, and cross          *
  29      *    platform software that is more than just the market leader, it     *
  30      *    is the industry's de facto standard.                               *
  31      *                                                                       *
  32      *    Help yourself get started quickly while simultaneously helping     *
  33      *    to support the FreeRTOS project by purchasing a FreeRTOS           *
  34      *    tutorial book, reference manual, or both:                          *
  35      *    http://www.FreeRTOS.org/Documentation                              *
  36      *                                                                       *
  37     ***************************************************************************
  38
  39     http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
  40     the FAQ page "My application does not run, what could be wrong?".  Have you
  41     defined configASSERT()?
  42
  43     http://www.FreeRTOS.org/support - In return for receiving this top quality
  44     embedded software for free we request you assist our global community by
  45     participating in the support forum.
  46
  47     http://www.FreeRTOS.org/training - Investing in training allows your team to
  48     be as productive as possible as early as possible.  Now you can receive
  49     FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
  50     Ltd, and the world's leading authority on the world's leading RTOS.
  51
  52     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
  53     including FreeRTOS+Trace - an indispensable productivity tool, a DOS
  54     compatible FAT file system, and our tiny thread aware UDP/IP stack.
  55
  56     http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
  57     Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
  58
  59     http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
  60     Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
  61     licenses offer ticketed support, indemnification and commercial middleware.
  62
  63     http://www.SafeRTOS.com - High Integrity Systems also provide a safety
  64     engineered and independently SIL3 certified version for use in safety and
  65     mission critical applications that require provable dependability.
  66
  67     1 tab == 4 spaces!
  68 */
  69
  70 #include "FreeRTOS.h"
  71 #include "task.h"
  72 #include "croutine.h"
  73
  74 /* Remove the whole file is co-routines are not being used. */
  75 #if( configUSE_CO_ROUTINES != 0 )
  76
  77 /*
  78  * Some kernel aware debuggers require data to be viewed to be global, rather
  79  * than file scope.
  80  */
  81 #ifdef portREMOVE_STATIC_QUALIFIER
  82         #define static
  83 #endif
  84
  85
  86 /* Lists for ready and blocked co-routines. --------------------*/
  87 static List_t pxReadyCoRoutineLists[ configMAX_CO_ROUTINE_PRIORITIES ]; /*< Prioritised ready co-routines. */
  88 static List_t xDelayedCoRoutineList1;                                                                   /*< Delayed co-routines. */
  89 static List_t xDelayedCoRoutineList2;                                                                   /*< Delayed co-routines (two lists are used - one for delays that have overflowed the current tick count. */
  90 static List_t * pxDelayedCoRoutineList;                                                                 /*< Points to the delayed co-routine list currently being used. */
  91 static List_t * pxOverflowDelayedCoRoutineList;                                                 /*< Points to the delayed co-routine list currently being used to hold co-routines that have overflowed the current tick count. */
  92 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. */
  93
  94 /* Other file private variables. --------------------------------*/
  95 CRCB_t * pxCurrentCoRoutine = NULL;
  96 static UBaseType_t uxTopCoRoutineReadyPriority = 0;
  97 static TickType_t xCoRoutineTickCount = 0, xLastTickCount = 0, xPassedTicks = 0;
  98
  99 /* The initial state of the co-routine when it is created. */
 100 #define corINITIAL_STATE        ( 0 )
 101
 102 /*
 103  * Place the co-routine represented by pxCRCB into the appropriate ready queue
 104  * for the priority.  It is inserted at the end of the list.
 105  *
 106  * This macro accesses the co-routine ready lists and therefore must not be
 107  * used from within an ISR.
 108  */
 109 #define prvAddCoRoutineToReadyQueue( pxCRCB )                                                                                                                                           \
 110 {                                                                                                                                                                                                                                       \
 111         if( pxCRCB->uxPriority > uxTopCoRoutineReadyPriority )                                                                                                                  \
 112         {                                                                                                                                                                                                                               \
 113                 uxTopCoRoutineReadyPriority = pxCRCB->uxPriority;                                                                                                                       \
 114         }                                                                                                                                                                                                                               \
 115         vListInsertEnd( ( List_t * ) &( pxReadyCoRoutineLists[ pxCRCB->uxPriority ] ), &( pxCRCB->xGenericListItem ) ); \
 116 }
 117
 118 /*
 119  * Utility to ready all the lists used by the scheduler.  This is called
 120  * automatically upon the creation of the first co-routine.
 121  */
 122 static void prvInitialiseCoRoutineLists( void );
 123
 124 /*
 125  * Co-routines that are readied by an interrupt cannot be placed directly into
 126  * the ready lists (there is no mutual exclusion).  Instead they are placed in
 127  * in the pending ready list in order that they can later be moved to the ready
 128  * list by the co-routine scheduler.
 129  */
 130 static void prvCheckPendingReadyList( void );
 131
 132 /*
 133  * Macro that looks at the list of co-routines that are currently delayed to
 134  * see if any require waking.
 135  *
 136  * Co-routines are stored in the queue in the order of their wake time -
 137  * meaning once one co-routine has been found whose timer has not expired
 138  * we need not look any further down the list.
 139  */
 140 static void prvCheckDelayedList( void );
 141
 142 /*-----------------------------------------------------------*/
 143
 144 BaseType_t xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, UBaseType_t uxPriority, UBaseType_t uxIndex )
 145 {
 146 BaseType_t xReturn;
 147 CRCB_t *pxCoRoutine;
 148
 149         /* Allocate the memory that will store the co-routine control block. */
 150         pxCoRoutine = ( CRCB_t * ) pvPortMalloc( sizeof( CRCB_t ) );
 151         if( pxCoRoutine )
 152         {
 153                 /* If pxCurrentCoRoutine is NULL then this is the first co-routine to
 154                 be created and the co-routine data structures need initialising. */
 155                 if( pxCurrentCoRoutine == NULL )
 156                 {
 157                         pxCurrentCoRoutine = pxCoRoutine;
 158                         prvInitialiseCoRoutineLists();
 159                 }
 160
 161                 /* Check the priority is within limits. */
 162                 if( uxPriority >= configMAX_CO_ROUTINE_PRIORITIES )
 163                 {
 164                         uxPriority = configMAX_CO_ROUTINE_PRIORITIES - 1;
 165                 }
 166
 167                 /* Fill out the co-routine control block from the function parameters. */
 168                 pxCoRoutine->uxState = corINITIAL_STATE;
 169                 pxCoRoutine->uxPriority = uxPriority;
 170                 pxCoRoutine->uxIndex = uxIndex;
 171                 pxCoRoutine->pxCoRoutineFunction = pxCoRoutineCode;
 172
 173                 /* Initialise all the other co-routine control block parameters. */
 174                 vListInitialiseItem( &( pxCoRoutine->xGenericListItem ) );
 175                 vListInitialiseItem( &( pxCoRoutine->xEventListItem ) );
 176
 177                 /* Set the co-routine control block as a link back from the ListItem_t.
 178                 This is so we can get back to the containing CRCB from a generic item
 179                 in a list. */
 180                 listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xGenericListItem ), pxCoRoutine );
 181                 listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xEventListItem ), pxCoRoutine );
 182
 183                 /* Event lists are always in priority order. */
 184                 listSET_LIST_ITEM_VALUE( &( pxCoRoutine->xEventListItem ), ( ( TickType_t ) configMAX_CO_ROUTINE_PRIORITIES - ( TickType_t ) uxPriority ) );
 185
 186                 /* Now the co-routine has been initialised it can be added to the ready
 187                 list at the correct priority. */
 188                 prvAddCoRoutineToReadyQueue( pxCoRoutine );
 189
 190                 xReturn = pdPASS;
 191         }
 192         else
 193         {
 194                 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
 195         }
 196
 197         return xReturn;
 198 }
 199 /*-----------------------------------------------------------*/
 200
 201 void vCoRoutineAddToDelayedList( TickType_t xTicksToDelay, List_t *pxEventList )
 202 {
 203 TickType_t xTimeToWake;
 204
 205         /* Calculate the time to wake - this may overflow but this is
 206         not a problem. */
 207         xTimeToWake = xCoRoutineTickCount + xTicksToDelay;
 208
 209         /* We must remove ourselves from the ready list before adding
 210         ourselves to the blocked list as the same list item is used for
 211         both lists. */
 212         ( void ) uxListRemove( ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
 213
 214         /* The list item will be inserted in wake time order. */
 215         listSET_LIST_ITEM_VALUE( &( pxCurrentCoRoutine->xGenericListItem ), xTimeToWake );
 216
 217         if( xTimeToWake < xCoRoutineTickCount )
 218         {
 219                 /* Wake time has overflowed.  Place this item in the
 220                 overflow list. */
 221                 vListInsert( ( List_t * ) pxOverflowDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
 222         }
 223         else
 224         {
 225                 /* The wake time has not overflowed, so we can use the
 226                 current block list. */
 227                 vListInsert( ( List_t * ) pxDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
 228         }
 229
 230         if( pxEventList )
 231         {
 232                 /* Also add the co-routine to an event list.  If this is done then the
 233                 function must be called with interrupts disabled. */
 234                 vListInsert( pxEventList, &( pxCurrentCoRoutine->xEventListItem ) );
 235         }
 236 }
 237 /*-----------------------------------------------------------*/
 238
 239 static void prvCheckPendingReadyList( void )
 240 {
 241         /* Are there any co-routines waiting to get moved to the ready list?  These
 242         are co-routines that have been readied by an ISR.  The ISR cannot access
 243         the     ready lists itself. */
 244         while( listLIST_IS_EMPTY( &xPendingReadyCoRoutineList ) == pdFALSE )
 245         {
 246                 CRCB_t *pxUnblockedCRCB;
 247
 248                 /* The pending ready list can be accessed by an ISR. */
 249                 portDISABLE_INTERRUPTS();
 250                 {
 251                         pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( (&xPendingReadyCoRoutineList) );
 252                         ( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) );
 253                 }
 254                 portENABLE_INTERRUPTS();
 255
 256                 ( void ) uxListRemove( &( pxUnblockedCRCB->xGenericListItem ) );
 257                 prvAddCoRoutineToReadyQueue( pxUnblockedCRCB );
 258         }
 259 }
 260 /*-----------------------------------------------------------*/
 261
 262 static void prvCheckDelayedList( void )
 263 {
 264 CRCB_t *pxCRCB;
 265
 266         xPassedTicks = xTaskGetTickCount() - xLastTickCount;
 267         while( xPassedTicks )
 268         {
 269                 xCoRoutineTickCount++;
 270                 xPassedTicks--;
 271
 272                 /* If the tick count has overflowed we need to swap the ready lists. */
 273                 if( xCoRoutineTickCount == 0 )
 274                 {
 275                         List_t * pxTemp;
 276
 277                         /* Tick count has overflowed so we need to swap the delay lists.  If there are
 278                         any items in pxDelayedCoRoutineList here then there is an error! */
 279                         pxTemp = pxDelayedCoRoutineList;
 280                         pxDelayedCoRoutineList = pxOverflowDelayedCoRoutineList;
 281                         pxOverflowDelayedCoRoutineList = pxTemp;
 282                 }
 283
 284                 /* See if this tick has made a timeout expire. */
 285                 while( listLIST_IS_EMPTY( pxDelayedCoRoutineList ) == pdFALSE )
 286                 {
 287                         pxCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedCoRoutineList );
 288
 289                         if( xCoRoutineTickCount < listGET_LIST_ITEM_VALUE( &( pxCRCB->xGenericListItem ) ) )
 290                         {
 291                                 /* Timeout not yet expired. */
 292                                 break;
 293                         }
 294
 295                         portDISABLE_INTERRUPTS();
 296                         {
 297                                 /* The event could have occurred just before this critical
 298                                 section.  If this is the case then the generic list item will
 299                                 have been moved to the pending ready list and the following
 300                                 line is still valid.  Also the pvContainer parameter will have
 301                                 been set to NULL so the following lines are also valid. */
 302                                 ( void ) uxListRemove( &( pxCRCB->xGenericListItem ) );
 303
 304                                 /* Is the co-routine waiting on an event also? */
 305                                 if( pxCRCB->xEventListItem.pvContainer )
 306                                 {
 307                                         ( void ) uxListRemove( &( pxCRCB->xEventListItem ) );
 308                                 }
 309                         }
 310                         portENABLE_INTERRUPTS();
 311
 312                         prvAddCoRoutineToReadyQueue( pxCRCB );
 313                 }
 314         }
 315
 316         xLastTickCount = xCoRoutineTickCount;
 317 }
 318 /*-----------------------------------------------------------*/
 319
 320 void vCoRoutineSchedule( void )
 321 {
 322         /* See if any co-routines readied by events need moving to the ready lists. */
 323         prvCheckPendingReadyList();
 324
 325         /* See if any delayed co-routines have timed out. */
 326         prvCheckDelayedList();
 327
 328         /* Find the highest priority queue that contains ready co-routines. */
 329         while( listLIST_IS_EMPTY( &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) ) )
 330         {
 331                 if( uxTopCoRoutineReadyPriority == 0 )
 332                 {
 333                         /* No more co-routines to check. */
 334                         return;
 335                 }
 336                 --uxTopCoRoutineReadyPriority;
 337         }
 338
 339         /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the co-routines
 340          of the same priority get an equal share of the processor time. */
 341         listGET_OWNER_OF_NEXT_ENTRY( pxCurrentCoRoutine, &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) );
 342
 343         /* Call the co-routine. */
 344         ( pxCurrentCoRoutine->pxCoRoutineFunction )( pxCurrentCoRoutine, pxCurrentCoRoutine->uxIndex );
 345
 346         return;
 347 }
 348 /*-----------------------------------------------------------*/
 349
 350 static void prvInitialiseCoRoutineLists( void )
 351 {
 352 UBaseType_t uxPriority;
 353
 354         for( uxPriority = 0; uxPriority < configMAX_CO_ROUTINE_PRIORITIES; uxPriority++ )
 355         {
 356                 vListInitialise( ( List_t * ) &( pxReadyCoRoutineLists[ uxPriority ] ) );
 357         }
 358
 359         vListInitialise( ( List_t * ) &xDelayedCoRoutineList1 );
 360         vListInitialise( ( List_t * ) &xDelayedCoRoutineList2 );
 361         vListInitialise( ( List_t * ) &xPendingReadyCoRoutineList );
 362
 363         /* Start with pxDelayedCoRoutineList using list1 and the
 364         pxOverflowDelayedCoRoutineList using list2. */
 365         pxDelayedCoRoutineList = &xDelayedCoRoutineList1;
 366         pxOverflowDelayedCoRoutineList = &xDelayedCoRoutineList2;
 367 }
 368 /*-----------------------------------------------------------*/
 369
 370 BaseType_t xCoRoutineRemoveFromEventList( const List_t *pxEventList )
 371 {
 372 CRCB_t *pxUnblockedCRCB;
 373 BaseType_t xReturn;
 374
 375         /* This function is called from within an interrupt.  It can only access
 376         event lists and the pending ready list.  This function assumes that a
 377         check has already been made to ensure pxEventList is not empty. */
 378         pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
 379         ( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) );
 380         vListInsertEnd( ( List_t * ) &( xPendingReadyCoRoutineList ), &( pxUnblockedCRCB->xEventListItem ) );
 381
 382         if( pxUnblockedCRCB->uxPriority >= pxCurrentCoRoutine->uxPriority )
 383         {
 384                 xReturn = pdTRUE;
 385         }
 386         else
 387         {
 388                 xReturn = pdFALSE;
 389         }
 390
 391         return xReturn;
 392 }
 393
 394 #endif /* configUSE_CO_ROUTINES == 0 */
 395