1 /* 2 * FreeRTOS Kernel V10.6.2 3 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. 4 * 5 * SPDX-License-Identifier: MIT 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy of 8 * this software and associated documentation files (the "Software"), to deal in 9 * the Software without restriction, including without limitation the rights to 10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 11 * the Software, and to permit persons to whom the Software is furnished to do so, 12 * subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in all 15 * copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR 20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 * 24 * https://www.FreeRTOS.org 25 * https://github.com/FreeRTOS 26 * 27 */ 28 29 #include "FreeRTOS.h" 30 #include "task.h" 31 #include "croutine.h" 32 33 /* Remove the whole file is co-routines are not being used. */ 34 #if ( configUSE_CO_ROUTINES != 0 ) 35 36 /* 37 * Some kernel aware debuggers require data to be viewed to be global, rather 38 * than file scope. 39 */ 40 #ifdef portREMOVE_STATIC_QUALIFIER 41 #define static 42 #endif 43 44 45 /* Lists for ready and blocked co-routines. --------------------*/ 46 static List_t pxReadyCoRoutineLists[ configMAX_CO_ROUTINE_PRIORITIES ]; /*< Prioritised ready co-routines. */ 47 static List_t xDelayedCoRoutineList1; /*< Delayed co-routines. */ 48 static List_t xDelayedCoRoutineList2; /*< Delayed co-routines (two lists are used - one for delays that have overflowed the current tick count. */ 49 static List_t * pxDelayedCoRoutineList = NULL; /*< Points to the delayed co-routine list currently being used. */ 50 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. */ 51 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. */ 52 53 /* Other file private variables. --------------------------------*/ 54 CRCB_t * pxCurrentCoRoutine = NULL; 55 static UBaseType_t uxTopCoRoutineReadyPriority = 0; 56 static TickType_t xCoRoutineTickCount = 0, xLastTickCount = 0, xPassedTicks = 0; 57 58 /* The initial state of the co-routine when it is created. */ 59 #define corINITIAL_STATE ( 0 ) 60 61 /* 62 * Place the co-routine represented by pxCRCB into the appropriate ready queue 63 * for the priority. It is inserted at the end of the list. 64 * 65 * This macro accesses the co-routine ready lists and therefore must not be 66 * used from within an ISR. 67 */ 68 #define prvAddCoRoutineToReadyQueue( pxCRCB ) \ 69 do { \ 70 if( ( pxCRCB )->uxPriority > uxTopCoRoutineReadyPriority ) \ 71 { \ 72 uxTopCoRoutineReadyPriority = ( pxCRCB )->uxPriority; \ 73 } \ 74 vListInsertEnd( ( List_t * ) &( pxReadyCoRoutineLists[ ( pxCRCB )->uxPriority ] ), &( ( pxCRCB )->xGenericListItem ) ); \ 75 } while( 0 ) 76 77 /* 78 * Utility to ready all the lists used by the scheduler. This is called 79 * automatically upon the creation of the first co-routine. 80 */ 81 static void prvInitialiseCoRoutineLists( void ); 82 83 /* 84 * Co-routines that are readied by an interrupt cannot be placed directly into 85 * the ready lists (there is no mutual exclusion). Instead they are placed in 86 * in the pending ready list in order that they can later be moved to the ready 87 * list by the co-routine scheduler. 88 */ 89 static void prvCheckPendingReadyList( void ); 90 91 /* 92 * Macro that looks at the list of co-routines that are currently delayed to 93 * see if any require waking. 94 * 95 * Co-routines are stored in the queue in the order of their wake time - 96 * meaning once one co-routine has been found whose timer has not expired 97 * we need not look any further down the list. 98 */ 99 static void prvCheckDelayedList( void ); 100 101 /*-----------------------------------------------------------*/ 102 xCoRoutineCreate(crCOROUTINE_CODE pxCoRoutineCode,UBaseType_t uxPriority,UBaseType_t uxIndex)103 BaseType_t xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, 104 UBaseType_t uxPriority, 105 UBaseType_t uxIndex ) 106 { 107 BaseType_t xReturn; 108 CRCB_t * pxCoRoutine; 109 110 /* Allocate the memory that will store the co-routine control block. */ 111 pxCoRoutine = ( CRCB_t * ) pvPortMalloc( sizeof( CRCB_t ) ); 112 113 if( pxCoRoutine ) 114 { 115 /* If pxCurrentCoRoutine is NULL then this is the first co-routine to 116 * be created and the co-routine data structures need initialising. */ 117 if( pxCurrentCoRoutine == NULL ) 118 { 119 pxCurrentCoRoutine = pxCoRoutine; 120 prvInitialiseCoRoutineLists(); 121 } 122 123 /* Check the priority is within limits. */ 124 if( uxPriority >= configMAX_CO_ROUTINE_PRIORITIES ) 125 { 126 uxPriority = configMAX_CO_ROUTINE_PRIORITIES - 1; 127 } 128 129 /* Fill out the co-routine control block from the function parameters. */ 130 pxCoRoutine->uxState = corINITIAL_STATE; 131 pxCoRoutine->uxPriority = uxPriority; 132 pxCoRoutine->uxIndex = uxIndex; 133 pxCoRoutine->pxCoRoutineFunction = pxCoRoutineCode; 134 135 /* Initialise all the other co-routine control block parameters. */ 136 vListInitialiseItem( &( pxCoRoutine->xGenericListItem ) ); 137 vListInitialiseItem( &( pxCoRoutine->xEventListItem ) ); 138 139 /* Set the co-routine control block as a link back from the ListItem_t. 140 * This is so we can get back to the containing CRCB from a generic item 141 * in a list. */ 142 listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xGenericListItem ), pxCoRoutine ); 143 listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xEventListItem ), pxCoRoutine ); 144 145 /* Event lists are always in priority order. */ 146 listSET_LIST_ITEM_VALUE( &( pxCoRoutine->xEventListItem ), ( ( TickType_t ) configMAX_CO_ROUTINE_PRIORITIES - ( TickType_t ) uxPriority ) ); 147 148 /* Now the co-routine has been initialised it can be added to the ready 149 * list at the correct priority. */ 150 prvAddCoRoutineToReadyQueue( pxCoRoutine ); 151 152 xReturn = pdPASS; 153 } 154 else 155 { 156 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY; 157 } 158 159 return xReturn; 160 } 161 /*-----------------------------------------------------------*/ 162 vCoRoutineAddToDelayedList(TickType_t xTicksToDelay,List_t * pxEventList)163 void vCoRoutineAddToDelayedList( TickType_t xTicksToDelay, 164 List_t * pxEventList ) 165 { 166 TickType_t xTimeToWake; 167 168 /* Calculate the time to wake - this may overflow but this is 169 * not a problem. */ 170 xTimeToWake = xCoRoutineTickCount + xTicksToDelay; 171 172 /* We must remove ourselves from the ready list before adding 173 * ourselves to the blocked list as the same list item is used for 174 * both lists. */ 175 ( void ) uxListRemove( ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) ); 176 177 /* The list item will be inserted in wake time order. */ 178 listSET_LIST_ITEM_VALUE( &( pxCurrentCoRoutine->xGenericListItem ), xTimeToWake ); 179 180 if( xTimeToWake < xCoRoutineTickCount ) 181 { 182 /* Wake time has overflowed. Place this item in the 183 * overflow list. */ 184 vListInsert( ( List_t * ) pxOverflowDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) ); 185 } 186 else 187 { 188 /* The wake time has not overflowed, so we can use the 189 * current block list. */ 190 vListInsert( ( List_t * ) pxDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) ); 191 } 192 193 if( pxEventList ) 194 { 195 /* Also add the co-routine to an event list. If this is done then the 196 * function must be called with interrupts disabled. */ 197 vListInsert( pxEventList, &( pxCurrentCoRoutine->xEventListItem ) ); 198 } 199 } 200 /*-----------------------------------------------------------*/ 201 prvCheckPendingReadyList(void)202 static void prvCheckPendingReadyList( void ) 203 { 204 /* Are there any co-routines waiting to get moved to the ready list? These 205 * are co-routines that have been readied by an ISR. The ISR cannot access 206 * the ready lists itself. */ 207 while( listLIST_IS_EMPTY( &xPendingReadyCoRoutineList ) == pdFALSE ) 208 { 209 CRCB_t * pxUnblockedCRCB; 210 211 /* The pending ready list can be accessed by an ISR. */ 212 portDISABLE_INTERRUPTS(); 213 { 214 pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( ( &xPendingReadyCoRoutineList ) ); 215 ( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) ); 216 } 217 portENABLE_INTERRUPTS(); 218 219 ( void ) uxListRemove( &( pxUnblockedCRCB->xGenericListItem ) ); 220 prvAddCoRoutineToReadyQueue( pxUnblockedCRCB ); 221 } 222 } 223 /*-----------------------------------------------------------*/ 224 prvCheckDelayedList(void)225 static void prvCheckDelayedList( void ) 226 { 227 CRCB_t * pxCRCB; 228 229 xPassedTicks = xTaskGetTickCount() - xLastTickCount; 230 231 while( xPassedTicks ) 232 { 233 xCoRoutineTickCount++; 234 xPassedTicks--; 235 236 /* If the tick count has overflowed we need to swap the ready lists. */ 237 if( xCoRoutineTickCount == 0 ) 238 { 239 List_t * pxTemp; 240 241 /* Tick count has overflowed so we need to swap the delay lists. If there are 242 * any items in pxDelayedCoRoutineList here then there is an error! */ 243 pxTemp = pxDelayedCoRoutineList; 244 pxDelayedCoRoutineList = pxOverflowDelayedCoRoutineList; 245 pxOverflowDelayedCoRoutineList = pxTemp; 246 } 247 248 /* See if this tick has made a timeout expire. */ 249 while( listLIST_IS_EMPTY( pxDelayedCoRoutineList ) == pdFALSE ) 250 { 251 pxCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedCoRoutineList ); 252 253 if( xCoRoutineTickCount < listGET_LIST_ITEM_VALUE( &( pxCRCB->xGenericListItem ) ) ) 254 { 255 /* Timeout not yet expired. */ 256 break; 257 } 258 259 portDISABLE_INTERRUPTS(); 260 { 261 /* The event could have occurred just before this critical 262 * section. If this is the case then the generic list item will 263 * have been moved to the pending ready list and the following 264 * line is still valid. Also the pvContainer parameter will have 265 * been set to NULL so the following lines are also valid. */ 266 ( void ) uxListRemove( &( pxCRCB->xGenericListItem ) ); 267 268 /* Is the co-routine waiting on an event also? */ 269 if( pxCRCB->xEventListItem.pxContainer ) 270 { 271 ( void ) uxListRemove( &( pxCRCB->xEventListItem ) ); 272 } 273 } 274 portENABLE_INTERRUPTS(); 275 276 prvAddCoRoutineToReadyQueue( pxCRCB ); 277 } 278 } 279 280 xLastTickCount = xCoRoutineTickCount; 281 } 282 /*-----------------------------------------------------------*/ 283 vCoRoutineSchedule(void)284 void vCoRoutineSchedule( void ) 285 { 286 /* Only run a co-routine after prvInitialiseCoRoutineLists() has been 287 * called. prvInitialiseCoRoutineLists() is called automatically when a 288 * co-routine is created. */ 289 if( pxDelayedCoRoutineList != NULL ) 290 { 291 /* See if any co-routines readied by events need moving to the ready lists. */ 292 prvCheckPendingReadyList(); 293 294 /* See if any delayed co-routines have timed out. */ 295 prvCheckDelayedList(); 296 297 /* Find the highest priority queue that contains ready co-routines. */ 298 while( listLIST_IS_EMPTY( &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) ) ) 299 { 300 if( uxTopCoRoutineReadyPriority == 0 ) 301 { 302 /* No more co-routines to check. */ 303 return; 304 } 305 306 --uxTopCoRoutineReadyPriority; 307 } 308 309 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the co-routines 310 * of the same priority get an equal share of the processor time. */ 311 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentCoRoutine, &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) ); 312 313 /* Call the co-routine. */ 314 ( pxCurrentCoRoutine->pxCoRoutineFunction )( pxCurrentCoRoutine, pxCurrentCoRoutine->uxIndex ); 315 } 316 } 317 /*-----------------------------------------------------------*/ 318 prvInitialiseCoRoutineLists(void)319 static void prvInitialiseCoRoutineLists( void ) 320 { 321 UBaseType_t uxPriority; 322 323 for( uxPriority = 0; uxPriority < configMAX_CO_ROUTINE_PRIORITIES; uxPriority++ ) 324 { 325 vListInitialise( ( List_t * ) &( pxReadyCoRoutineLists[ uxPriority ] ) ); 326 } 327 328 vListInitialise( ( List_t * ) &xDelayedCoRoutineList1 ); 329 vListInitialise( ( List_t * ) &xDelayedCoRoutineList2 ); 330 vListInitialise( ( List_t * ) &xPendingReadyCoRoutineList ); 331 332 /* Start with pxDelayedCoRoutineList using list1 and the 333 * pxOverflowDelayedCoRoutineList using list2. */ 334 pxDelayedCoRoutineList = &xDelayedCoRoutineList1; 335 pxOverflowDelayedCoRoutineList = &xDelayedCoRoutineList2; 336 } 337 /*-----------------------------------------------------------*/ 338 xCoRoutineRemoveFromEventList(const List_t * pxEventList)339 BaseType_t xCoRoutineRemoveFromEventList( const List_t * pxEventList ) 340 { 341 CRCB_t * pxUnblockedCRCB; 342 BaseType_t xReturn; 343 344 /* This function is called from within an interrupt. It can only access 345 * event lists and the pending ready list. This function assumes that a 346 * check has already been made to ensure pxEventList is not empty. */ 347 pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList ); 348 ( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) ); 349 vListInsertEnd( ( List_t * ) &( xPendingReadyCoRoutineList ), &( pxUnblockedCRCB->xEventListItem ) ); 350 351 if( pxUnblockedCRCB->uxPriority >= pxCurrentCoRoutine->uxPriority ) 352 { 353 xReturn = pdTRUE; 354 } 355 else 356 { 357 xReturn = pdFALSE; 358 } 359 360 return xReturn; 361 } 362 363 #endif /* configUSE_CO_ROUTINES == 0 */ 364
