1 /*
2 * FreeRTOS Kernel V10.2.1
3 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
6 * this software and associated documentation files (the "Software"), to deal in
7 * the Software without restriction, including without limitation the rights to
8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
9 * the Software, and to permit persons to whom the Software is furnished to do so,
10 * subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in all
13 * copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * http://www.FreeRTOS.org
23 * http://aws.amazon.com/freertos
24 *
25 * 1 tab == 4 spaces!
26 */
27
28 #include "FreeRTOS.h"
29 #include "task.h"
30 #include "croutine.h"
31
32 /* Remove the whole file is co-routines are not being used. */
33 #if( configUSE_CO_ROUTINES != 0 )
34
35 /*
36 * Some kernel aware debuggers require data to be viewed to be global, rather
37 * than file scope.
38 */
39 #ifdef portREMOVE_STATIC_QUALIFIER
40 #define static
41 #endif
42
43
44 /* Lists for ready and blocked co-routines. --------------------*/
45 static List_t pxReadyCoRoutineLists[ configMAX_CO_ROUTINE_PRIORITIES ]; /*< Prioritised ready co-routines. */
46 static List_t xDelayedCoRoutineList1; /*< Delayed co-routines. */
47 static List_t xDelayedCoRoutineList2; /*< Delayed co-routines (two lists are used - one for delays that have overflowed the current tick count. */
48 static List_t * pxDelayedCoRoutineList; /*< Points to the delayed co-routine list currently being used. */
49 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. */
50 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. */
51
52 /* Other file private variables. --------------------------------*/
53 CRCB_t * pxCurrentCoRoutine = NULL;
54 static UBaseType_t uxTopCoRoutineReadyPriority = 0;
55 static TickType_t xCoRoutineTickCount = 0, xLastTickCount = 0, xPassedTicks = 0;
56
57 /* The initial state of the co-routine when it is created. */
58 #define corINITIAL_STATE ( 0 )
59
60 /*
61 * Place the co-routine represented by pxCRCB into the appropriate ready queue
62 * for the priority. It is inserted at the end of the list.
63 *
64 * This macro accesses the co-routine ready lists and therefore must not be
65 * used from within an ISR.
66 */
67 #define prvAddCoRoutineToReadyQueue( pxCRCB ) \
68 { \
69 if( pxCRCB->uxPriority > uxTopCoRoutineReadyPriority ) \
70 { \
71 uxTopCoRoutineReadyPriority = pxCRCB->uxPriority; \
72 } \
73 vListInsertEnd( ( List_t * ) &( pxReadyCoRoutineLists[ pxCRCB->uxPriority ] ), &( pxCRCB->xGenericListItem ) ); \
74 }
75
76 /*
77 * Utility to ready all the lists used by the scheduler. This is called
78 * automatically upon the creation of the first co-routine.
79 */
80 static void prvInitialiseCoRoutineLists( void );
81
82 /*
83 * Co-routines that are readied by an interrupt cannot be placed directly into
84 * the ready lists (there is no mutual exclusion). Instead they are placed in
85 * in the pending ready list in order that they can later be moved to the ready
86 * list by the co-routine scheduler.
87 */
88 static void prvCheckPendingReadyList( void );
89
90 /*
91 * Macro that looks at the list of co-routines that are currently delayed to
92 * see if any require waking.
93 *
94 * Co-routines are stored in the queue in the order of their wake time -
95 * meaning once one co-routine has been found whose timer has not expired
96 * we need not look any further down the list.
97 */
98 static void prvCheckDelayedList( void );
99
100 /*-----------------------------------------------------------*/
101
xCoRoutineCreate(crCOROUTINE_CODE pxCoRoutineCode,UBaseType_t uxPriority,UBaseType_t uxIndex)102 BaseType_t xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, UBaseType_t uxPriority, UBaseType_t uxIndex )
103 {
104 BaseType_t xReturn;
105 CRCB_t *pxCoRoutine;
106
107 /* Allocate the memory that will store the co-routine control block. */
108 pxCoRoutine = ( CRCB_t * ) pvPortMalloc( sizeof( CRCB_t ) );
109 if( pxCoRoutine )
110 {
111 /* If pxCurrentCoRoutine is NULL then this is the first co-routine to
112 be created and the co-routine data structures need initialising. */
113 if( pxCurrentCoRoutine == NULL )
114 {
115 pxCurrentCoRoutine = pxCoRoutine;
116 prvInitialiseCoRoutineLists();
117 }
118
119 /* Check the priority is within limits. */
120 if( uxPriority >= configMAX_CO_ROUTINE_PRIORITIES )
121 {
122 uxPriority = configMAX_CO_ROUTINE_PRIORITIES - 1;
123 }
124
125 /* Fill out the co-routine control block from the function parameters. */
126 pxCoRoutine->uxState = corINITIAL_STATE;
127 pxCoRoutine->uxPriority = uxPriority;
128 pxCoRoutine->uxIndex = uxIndex;
129 pxCoRoutine->pxCoRoutineFunction = pxCoRoutineCode;
130
131 /* Initialise all the other co-routine control block parameters. */
132 vListInitialiseItem( &( pxCoRoutine->xGenericListItem ) );
133 vListInitialiseItem( &( pxCoRoutine->xEventListItem ) );
134
135 /* Set the co-routine control block as a link back from the ListItem_t.
136 This is so we can get back to the containing CRCB from a generic item
137 in a list. */
138 listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xGenericListItem ), pxCoRoutine );
139 listSET_LIST_ITEM_OWNER( &( pxCoRoutine->xEventListItem ), pxCoRoutine );
140
141 /* Event lists are always in priority order. */
142 listSET_LIST_ITEM_VALUE( &( pxCoRoutine->xEventListItem ), ( ( TickType_t ) configMAX_CO_ROUTINE_PRIORITIES - ( TickType_t ) uxPriority ) );
143
144 /* Now the co-routine has been initialised it can be added to the ready
145 list at the correct priority. */
146 prvAddCoRoutineToReadyQueue( pxCoRoutine );
147
148 xReturn = pdPASS;
149 }
150 else
151 {
152 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
153 }
154
155 return xReturn;
156 }
157 /*-----------------------------------------------------------*/
158
vCoRoutineAddToDelayedList(TickType_t xTicksToDelay,List_t * pxEventList)159 void vCoRoutineAddToDelayedList( TickType_t xTicksToDelay, List_t *pxEventList )
160 {
161 TickType_t xTimeToWake;
162
163 /* Calculate the time to wake - this may overflow but this is
164 not a problem. */
165 xTimeToWake = xCoRoutineTickCount + xTicksToDelay;
166
167 /* We must remove ourselves from the ready list before adding
168 ourselves to the blocked list as the same list item is used for
169 both lists. */
170 ( void ) uxListRemove( ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
171
172 /* The list item will be inserted in wake time order. */
173 listSET_LIST_ITEM_VALUE( &( pxCurrentCoRoutine->xGenericListItem ), xTimeToWake );
174
175 if( xTimeToWake < xCoRoutineTickCount )
176 {
177 /* Wake time has overflowed. Place this item in the
178 overflow list. */
179 vListInsert( ( List_t * ) pxOverflowDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
180 }
181 else
182 {
183 /* The wake time has not overflowed, so we can use the
184 current block list. */
185 vListInsert( ( List_t * ) pxDelayedCoRoutineList, ( ListItem_t * ) &( pxCurrentCoRoutine->xGenericListItem ) );
186 }
187
188 if( pxEventList )
189 {
190 /* Also add the co-routine to an event list. If this is done then the
191 function must be called with interrupts disabled. */
192 vListInsert( pxEventList, &( pxCurrentCoRoutine->xEventListItem ) );
193 }
194 }
195 /*-----------------------------------------------------------*/
196
prvCheckPendingReadyList(void)197 static void prvCheckPendingReadyList( void )
198 {
199 /* Are there any co-routines waiting to get moved to the ready list? These
200 are co-routines that have been readied by an ISR. The ISR cannot access
201 the ready lists itself. */
202 while( listLIST_IS_EMPTY( &xPendingReadyCoRoutineList ) == pdFALSE )
203 {
204 CRCB_t *pxUnblockedCRCB;
205
206 /* The pending ready list can be accessed by an ISR. */
207 portDISABLE_INTERRUPTS();
208 {
209 pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( (&xPendingReadyCoRoutineList) );
210 ( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) );
211 }
212 portENABLE_INTERRUPTS();
213
214 ( void ) uxListRemove( &( pxUnblockedCRCB->xGenericListItem ) );
215 prvAddCoRoutineToReadyQueue( pxUnblockedCRCB );
216 }
217 }
218 /*-----------------------------------------------------------*/
219
prvCheckDelayedList(void)220 static void prvCheckDelayedList( void )
221 {
222 CRCB_t *pxCRCB;
223
224 xPassedTicks = xTaskGetTickCount() - xLastTickCount;
225 while( xPassedTicks )
226 {
227 xCoRoutineTickCount++;
228 xPassedTicks--;
229
230 /* If the tick count has overflowed we need to swap the ready lists. */
231 if( xCoRoutineTickCount == 0 )
232 {
233 List_t * pxTemp;
234
235 /* Tick count has overflowed so we need to swap the delay lists. If there are
236 any items in pxDelayedCoRoutineList here then there is an error! */
237 pxTemp = pxDelayedCoRoutineList;
238 pxDelayedCoRoutineList = pxOverflowDelayedCoRoutineList;
239 pxOverflowDelayedCoRoutineList = pxTemp;
240 }
241
242 /* See if this tick has made a timeout expire. */
243 while( listLIST_IS_EMPTY( pxDelayedCoRoutineList ) == pdFALSE )
244 {
245 pxCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedCoRoutineList );
246
247 if( xCoRoutineTickCount < listGET_LIST_ITEM_VALUE( &( pxCRCB->xGenericListItem ) ) )
248 {
249 /* Timeout not yet expired. */
250 break;
251 }
252
253 portDISABLE_INTERRUPTS();
254 {
255 /* The event could have occurred just before this critical
256 section. If this is the case then the generic list item will
257 have been moved to the pending ready list and the following
258 line is still valid. Also the pvContainer parameter will have
259 been set to NULL so the following lines are also valid. */
260 ( void ) uxListRemove( &( pxCRCB->xGenericListItem ) );
261
262 /* Is the co-routine waiting on an event also? */
263 if( pxCRCB->xEventListItem.pxContainer )
264 {
265 ( void ) uxListRemove( &( pxCRCB->xEventListItem ) );
266 }
267 }
268 portENABLE_INTERRUPTS();
269
270 prvAddCoRoutineToReadyQueue( pxCRCB );
271 }
272 }
273
274 xLastTickCount = xCoRoutineTickCount;
275 }
276 /*-----------------------------------------------------------*/
277
vCoRoutineSchedule(void)278 void vCoRoutineSchedule( void )
279 {
280 /* See if any co-routines readied by events need moving to the ready lists. */
281 prvCheckPendingReadyList();
282
283 /* See if any delayed co-routines have timed out. */
284 prvCheckDelayedList();
285
286 /* Find the highest priority queue that contains ready co-routines. */
287 while( listLIST_IS_EMPTY( &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) ) )
288 {
289 if( uxTopCoRoutineReadyPriority == 0 )
290 {
291 /* No more co-routines to check. */
292 return;
293 }
294 --uxTopCoRoutineReadyPriority;
295 }
296
297 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the co-routines
298 of the same priority get an equal share of the processor time. */
299 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentCoRoutine, &( pxReadyCoRoutineLists[ uxTopCoRoutineReadyPriority ] ) );
300
301 /* Call the co-routine. */
302 ( pxCurrentCoRoutine->pxCoRoutineFunction )( pxCurrentCoRoutine, pxCurrentCoRoutine->uxIndex );
303
304 return;
305 }
306 /*-----------------------------------------------------------*/
307
prvInitialiseCoRoutineLists(void)308 static void prvInitialiseCoRoutineLists( void )
309 {
310 UBaseType_t uxPriority;
311
312 for( uxPriority = 0; uxPriority < configMAX_CO_ROUTINE_PRIORITIES; uxPriority++ )
313 {
314 vListInitialise( ( List_t * ) &( pxReadyCoRoutineLists[ uxPriority ] ) );
315 }
316
317 vListInitialise( ( List_t * ) &xDelayedCoRoutineList1 );
318 vListInitialise( ( List_t * ) &xDelayedCoRoutineList2 );
319 vListInitialise( ( List_t * ) &xPendingReadyCoRoutineList );
320
321 /* Start with pxDelayedCoRoutineList using list1 and the
322 pxOverflowDelayedCoRoutineList using list2. */
323 pxDelayedCoRoutineList = &xDelayedCoRoutineList1;
324 pxOverflowDelayedCoRoutineList = &xDelayedCoRoutineList2;
325 }
326 /*-----------------------------------------------------------*/
327
xCoRoutineRemoveFromEventList(const List_t * pxEventList)328 BaseType_t xCoRoutineRemoveFromEventList( const List_t *pxEventList )
329 {
330 CRCB_t *pxUnblockedCRCB;
331 BaseType_t xReturn;
332
333 /* This function is called from within an interrupt. It can only access
334 event lists and the pending ready list. This function assumes that a
335 check has already been made to ensure pxEventList is not empty. */
336 pxUnblockedCRCB = ( CRCB_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
337 ( void ) uxListRemove( &( pxUnblockedCRCB->xEventListItem ) );
338 vListInsertEnd( ( List_t * ) &( xPendingReadyCoRoutineList ), &( pxUnblockedCRCB->xEventListItem ) );
339
340 if( pxUnblockedCRCB->uxPriority >= pxCurrentCoRoutine->uxPriority )
341 {
342 xReturn = pdTRUE;
343 }
344 else
345 {
346 xReturn = pdFALSE;
347 }
348
349 return xReturn;
350 }
351
352 #endif /* configUSE_CO_ROUTINES == 0 */
353
