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1 /*\r
2         FreeRTOS.org V5.0.0 - Copyright (C) 2003-2008 Richard Barry.\r
3 \r
4         This file is part of the FreeRTOS.org distribution.\r
5 \r
6         FreeRTOS.org is free software; you can redistribute it and/or modify\r
7         it under the terms of the GNU General Public License as published by\r
8         the Free Software Foundation; either version 2 of the License, or\r
9         (at your option) any later version.\r
10 \r
11         FreeRTOS.org is distributed in the hope that it will be useful,\r
12         but WITHOUT ANY WARRANTY; without even the implied warranty of\r
13         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
14         GNU General Public License for more details.\r
15 \r
16         You should have received a copy of the GNU General Public License\r
17         along with FreeRTOS.org; if not, write to the Free Software\r
18         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\r
19 \r
20         A special exception to the GPL can be applied should you wish to distribute\r
21         a combined work that includes FreeRTOS.org, without being obliged to provide\r
22         the source code for any proprietary components.  See the licensing section\r
23         of http://www.FreeRTOS.org for full details of how and when the exception\r
24         can be applied.\r
25 \r
26     ***************************************************************************\r
27     ***************************************************************************\r
28     *                                                                         *\r
29     * SAVE TIME AND MONEY!  We can port FreeRTOS.org to your own hardware,    *\r
30     * and even write all or part of your application on your behalf.          *\r
31     * See http://www.OpenRTOS.com for details of the services we provide to   *\r
32     * expedite your project.                                                  *\r
33     *                                                                         *\r
34     ***************************************************************************\r
35     ***************************************************************************\r
36 \r
37         Please ensure to read the configuration and relevant port sections of the\r
38         online documentation.\r
39 \r
40         http://www.FreeRTOS.org - Documentation, latest information, license and \r
41         contact details.\r
42 \r
43         http://www.SafeRTOS.com - A version that is certified for use in safety \r
44         critical systems.\r
45 \r
46         http://www.OpenRTOS.com - Commercial support, development, porting, \r
47         licensing and training services.\r
48 */\r
49 \r
50 \r
51 #include <stdio.h>\r
52 #include <stdlib.h>\r
53 #include <string.h>\r
54 \r
55 #include "FreeRTOS.h"\r
56 #include "task.h"\r
57 \r
58 /*\r
59  * Macro to define the amount of stack available to the idle task.\r
60  */\r
61 #define tskIDLE_STACK_SIZE      configMINIMAL_STACK_SIZE\r
62 \r
63 \r
64 /*\r
65  * Task control block.  A task control block (TCB) is allocated to each task,\r
66  * and stores the context of the task.\r
67  */\r
68 typedef struct tskTaskControlBlock\r
69 {\r
70         volatile portSTACK_TYPE *pxTopOfStack;          /*< Points to the location of the last item placed on the tasks stack.  THIS MUST BE THE FIRST MEMBER OF THE STRUCT. */\r
71         xListItem                               xGenericListItem;       /*< List item used to place the TCB in ready and blocked queues. */\r
72         xListItem                               xEventListItem;         /*< List item used to place the TCB in event lists. */\r
73         unsigned portBASE_TYPE  uxPriority;                     /*< The priority of the task where 0 is the lowest priority. */\r
74         portSTACK_TYPE                  *pxStack;                       /*< Points to the start of the stack. */\r
75         signed portCHAR                 pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */\r
76 \r
77         #if ( portCRITICAL_NESTING_IN_TCB == 1 )\r
78                 unsigned portBASE_TYPE uxCriticalNesting;\r
79         #endif\r
80 \r
81         #if ( configUSE_TRACE_FACILITY == 1 )\r
82                 unsigned portBASE_TYPE  uxTCBNumber;            /*< This is used for tracing the scheduler and making debugging easier only. */\r
83         #endif  \r
84                 \r
85         #if ( configUSE_MUTEXES == 1 )\r
86                 unsigned portBASE_TYPE uxBasePriority;\r
87         #endif\r
88 \r
89         #if ( configUSE_APPLICATION_TASK_TAG == 1 )\r
90                 pdTASK_HOOK_CODE pxTaskTag;\r
91         #endif\r
92                 \r
93 } tskTCB;\r
94 \r
95 /*lint -e956 */\r
96 \r
97 tskTCB * volatile pxCurrentTCB = NULL;                                  \r
98 \r
99 /* Lists for ready and blocked tasks. --------------------*/\r
100 \r
101 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */\r
102 static xList xDelayedTaskList1;                                                 /*< Delayed tasks. */\r
103 static xList xDelayedTaskList2;                                                 /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */\r
104 static xList * volatile pxDelayedTaskList;                              /*< Points to the delayed task list currently being used. */\r
105 static xList * volatile pxOverflowDelayedTaskList;              /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */\r
106 static xList xPendingReadyList;                                                 /*< Tasks that have been readied while the scheduler was suspended.  They will be moved to the ready queue when the scheduler is resumed. */\r
107 \r
108 #if ( INCLUDE_vTaskDelete == 1 )\r
109 \r
110         static volatile xList xTasksWaitingTermination;         /*< Tasks that have been deleted - but the their memory not yet freed. */\r
111         static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;\r
112 \r
113 #endif\r
114 \r
115 #if ( INCLUDE_vTaskSuspend == 1 )\r
116 \r
117         static xList xSuspendedTaskList;                                        /*< Tasks that are currently suspended. */\r
118 \r
119 #endif\r
120 \r
121 /* File private variables. --------------------------------*/\r
122 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks   = ( unsigned portBASE_TYPE ) 0;\r
123 static volatile portTickType xTickCount                                                 = ( portTickType ) 0;\r
124 static unsigned portBASE_TYPE uxTopUsedPriority                                 = tskIDLE_PRIORITY;\r
125 static volatile unsigned portBASE_TYPE uxTopReadyPriority               = tskIDLE_PRIORITY;\r
126 static volatile signed portBASE_TYPE xSchedulerRunning                  = pdFALSE;\r
127 static volatile unsigned portBASE_TYPE uxSchedulerSuspended             = ( unsigned portBASE_TYPE ) pdFALSE;\r
128 static volatile unsigned portBASE_TYPE uxMissedTicks                    = ( unsigned portBASE_TYPE ) 0;\r
129 static volatile portBASE_TYPE xMissedYield                                              = ( portBASE_TYPE ) pdFALSE;\r
130 static volatile portBASE_TYPE xNumOfOverflows                                   = ( portBASE_TYPE ) 0;\r
131 /* Debugging and trace facilities private variables and macros. ------------*/\r
132 \r
133 /*\r
134  * The value used to fill the stack of a task when the task is created.  This\r
135  * is used purely for checking the high water mark for tasks.\r
136  */\r
137 #define tskSTACK_FILL_BYTE      ( 0xa5 )\r
138 \r
139 /*\r
140  * Macros used by vListTask to indicate which state a task is in.\r
141  */\r
142 #define tskBLOCKED_CHAR         ( ( signed portCHAR ) 'B' )\r
143 #define tskREADY_CHAR           ( ( signed portCHAR ) 'R' )\r
144 #define tskDELETED_CHAR         ( ( signed portCHAR ) 'D' )\r
145 #define tskSUSPENDED_CHAR       ( ( signed portCHAR ) 'S' )\r
146 \r
147 /*\r
148  * Macros and private variables used by the trace facility.\r
149  */\r
150 #if ( configUSE_TRACE_FACILITY == 1 )\r
151 \r
152         #define tskSIZE_OF_EACH_TRACE_LINE                      ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )\r
153         static volatile signed portCHAR * volatile pcTraceBuffer;\r
154         static signed portCHAR *pcTraceBufferStart;\r
155         static signed portCHAR *pcTraceBufferEnd;\r
156         static signed portBASE_TYPE xTracing = pdFALSE;\r
157 \r
158 #endif\r
159 \r
160 /*-----------------------------------------------------------*/\r
161 \r
162 /*\r
163  * Macro that writes a trace of scheduler activity to a buffer.  This trace\r
164  * shows which task is running when and is very useful as a debugging tool.\r
165  * As this macro is called each context switch it is a good idea to undefine\r
166  * it if not using the facility.\r
167  */\r
168 #if ( configUSE_TRACE_FACILITY == 1 )\r
169 \r
170         #define vWriteTraceToBuffer()                                                                                                                                   \\r
171         {                                                                                                                                                                                               \\r
172                 if( xTracing )                                                                                                                                                          \\r
173                 {                                                                                                                                                                                       \\r
174                         static unsigned portBASE_TYPE uxPreviousTask = 255;                                                                             \\r
175                                                                                                                                                                                                         \\r
176                         if( uxPreviousTask != pxCurrentTCB->uxTCBNumber )                                                                               \\r
177                         {                                                                                                                                                                               \\r
178                                 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd )                         \\r
179                                 {                                                                                                                                                                       \\r
180                                         uxPreviousTask = pxCurrentTCB->uxTCBNumber;                                                                             \\r
181                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount;              \\r
182                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
183                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask;  \\r
184                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
185                                 }                                                                                                                                                                       \\r
186                                 else                                                                                                                                                            \\r
187                                 {                                                                                                                                                                       \\r
188                                         xTracing = pdFALSE;                                                                                                                             \\r
189                                 }                                                                                                                                                                       \\r
190                         }                                                                                                                                                                               \\r
191                 }                                                                                                                                                                                       \\r
192         }\r
193 \r
194 #else\r
195 \r
196         #define vWriteTraceToBuffer()\r
197 \r
198 #endif\r
199 /*-----------------------------------------------------------*/\r
200 \r
201 /*\r
202  * Place the task represented by pxTCB into the appropriate ready queue for\r
203  * the task.  It is inserted at the end of the list.  One quirk of this is\r
204  * that if the task being inserted is at the same priority as the currently\r
205  * executing task, then it will only be rescheduled after the currently\r
206  * executing task has been rescheduled.\r
207  */\r
208 #define prvAddTaskToReadyQueue( pxTCB )                                                                                                                                                 \\r
209 {                                                                                                                                                                                                                               \\r
210         if( pxTCB->uxPriority > uxTopReadyPriority )                                                                                                                            \\r
211         {                                                                                                                                                                                                                       \\r
212                 uxTopReadyPriority = pxTCB->uxPriority;                                                                                                                                 \\r
213         }                                                                                                                                                                                                                       \\r
214         vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) );        \\r
215 }\r
216 /*-----------------------------------------------------------*/         \r
217 \r
218 /*\r
219  * Macro that looks at the list of tasks that are currently delayed to see if\r
220  * any require waking.\r
221  *\r
222  * Tasks are stored in the queue in the order of their wake time - meaning\r
223  * once one tasks has been found whose timer has not expired we need not look\r
224  * any further down the list.\r
225  */\r
226 #define prvCheckDelayedTasks()                                                                                                                                                                          \\r
227 {                                                                                                                                                                                                                                       \\r
228 register tskTCB *pxTCB;                                                                                                                                                                                         \\r
229                                                                                                                                                                                                                                         \\r
230         while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL )                                              \\r
231         {                                                                                                                                                                                                                               \\r
232                 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) )                                                                      \\r
233                 {                                                                                                                                                                                                                       \\r
234                         break;                                                                                                                                                                                                  \\r
235                 }                                                                                                                                                                                                                       \\r
236                 vListRemove( &( pxTCB->xGenericListItem ) );                                                                                                                            \\r
237                 /* Is the task waiting on an event also? */                                                                                                                                     \\r
238                 if( pxTCB->xEventListItem.pvContainer )                                                                                                                                         \\r
239                 {                                                                                                                                                                                                                       \\r
240                         vListRemove( &( pxTCB->xEventListItem ) );                                                                                                                              \\r
241                 }                                                                                                                                                                                                                       \\r
242                 prvAddTaskToReadyQueue( pxTCB );                                                                                                                                                        \\r
243         }                                                                                                                                                                                                                               \\r
244 }\r
245 /*-----------------------------------------------------------*/\r
246 \r
247 /*\r
248  * Call the stack overflow hook function if the stack of the task being swapped\r
249  * out is currently overflowed, or looks like it might have overflowed in the\r
250  * past.\r
251  *\r
252  * Setting configCHECK_FOR_STACK_OVERFLOW to 1 will cause the macro to check\r
253  * the current stack state only - comparing the current top of stack value to\r
254  * the stack limit.  Setting configCHECK_FOR_STACK_OVERFLOW to greater than 1\r
255  * will also cause the last few stack bytes to be checked to ensure the value\r
256  * to which the bytes were set when the task was created have not been \r
257  * overwritten.  Note this second test does not guarantee that an overflowed\r
258  * stack will always be recognised.\r
259  */\r
260 \r
261 #if( configCHECK_FOR_STACK_OVERFLOW == 0 )\r
262 \r
263         /* FreeRTOSConfig.h is not set to check for stack overflows. */\r
264         #define taskCHECK_FOR_STACK_OVERFLOW()\r
265 \r
266 #endif /* configCHECK_FOR_STACK_OVERFLOW == 0 */\r
267 \r
268 #if( ( configCHECK_FOR_STACK_OVERFLOW > 0 ) && ( portSTACK_GROWTH >= 0 ) )\r
269 \r
270         /* This is an invalid setting. */\r
271         #error configCHECK_FOR_STACK_OVERFLOW can only be set to a non zero value on architectures where the stack grows down from high memory.\r
272 \r
273 #endif /* ( configCHECK_FOR_STACK_OVERFLOW > 0 ) && ( portSTACK_GROWTH >= 0 ) */\r
274 \r
275 #if( configCHECK_FOR_STACK_OVERFLOW == 1 )\r
276 \r
277         /* Only the current stack state is to be checked. */\r
278         #define taskCHECK_FOR_STACK_OVERFLOW()                                                                                                                          \\r
279         {                                                                                                                                                                                                       \\r
280         extern void vApplicationStackOverflowHook( xTaskHandle *pxTask, signed portCHAR *pcTaskName );          \\r
281                                                                                                                                                                                                                 \\r
282                 /* Is the currently saved stack pointer within the stack limit? */                                                              \\r
283                 if( pxCurrentTCB->pxTopOfStack <= pxCurrentTCB->pxStack )                                                                               \\r
284                 {                                                                                                                                                                                               \\r
285                         vApplicationStackOverflowHook( ( xTaskHandle ) pxCurrentTCB, pxCurrentTCB->pcTaskName );        \\r
286                 }                                                                                                                                                                                               \\r
287         }\r
288 \r
289 #endif /* configCHECK_FOR_STACK_OVERFLOW == 1 */\r
290 \r
291 #if( configCHECK_FOR_STACK_OVERFLOW > 1 )\r
292 \r
293         /* Both the current statck state and the stack fill bytes are to be checked. */\r
294         #define taskCHECK_FOR_STACK_OVERFLOW()                                                                                                                                                                                                                  \\r
295         {                                                                                                                                                                                                                                                                                               \\r
296         extern void vApplicationStackOverflowHook( xTaskHandle *pxTask, signed portCHAR *pcTaskName );                                                                                                  \\r
297         static const unsigned portCHAR ucExpectedStackBytes[] = {       tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE,         \\r
298                                                                                                                                 tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE,         \\r
299                                                                                                                                 tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE,         \\r
300                                                                                                                                 tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE,         \\r
301                                                                                                                                 tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE, tskSTACK_FILL_BYTE };       \\r
302                                                                                                                                                                                                                                                                                                         \\r
303                 /* Is the currently saved stack pointer within the stack limit? */                                                                                                                                                      \\r
304                 if( pxCurrentTCB->pxTopOfStack <= pxCurrentTCB->pxStack )                                                                                                                                                                       \\r
305                 {                                                                                                                                                                                                                                                                                       \\r
306                         vApplicationStackOverflowHook( ( xTaskHandle ) pxCurrentTCB, pxCurrentTCB->pcTaskName );                                                                                                \\r
307                 }                                                                                                                                                                                                                                                                                       \\r
308                                                                                                                                                                                                                                                                                                         \\r
309                 /* Has the extremity of the task stack ever been written over? */                                                                                                                                                       \\r
310                 if( memcmp( ( void * ) pxCurrentTCB->pxStack, ( void * ) ucExpectedStackBytes, sizeof( ucExpectedStackBytes ) ) != 0 )                                          \\r
311                 {                                                                                                                                                                                                                                                                                       \\r
312                         vApplicationStackOverflowHook( ( xTaskHandle ) pxCurrentTCB, pxCurrentTCB->pcTaskName );                                                                                                \\r
313                 }                                                                                                                                                                                                                                                                                       \\r
314         }\r
315 \r
316 #endif /* #if( configCHECK_FOR_STACK_OVERFLOW > 1 ) */\r
317 \r
318 /*-----------------------------------------------------------*/\r
319 \r
320 /*\r
321  * Several functions take an xTaskHandle parameter that can optionally be NULL,\r
322  * where NULL is used to indicate that the handle of the currently executing\r
323  * task should be used in place of the parameter.  This macro simply checks to\r
324  * see if the parameter is NULL and returns a pointer to the appropriate TCB.\r
325  */\r
326 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )\r
327 \r
328 \r
329 /* File private functions. --------------------------------*/\r
330 \r
331 /*\r
332  * Utility to ready a TCB for a given task.  Mainly just copies the parameters\r
333  * into the TCB structure.\r
334  */\r
335 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );\r
336 \r
337 /*\r
338  * Utility to ready all the lists used by the scheduler.  This is called\r
339  * automatically upon the creation of the first task.\r
340  */\r
341 static void prvInitialiseTaskLists( void );\r
342 \r
343 /*\r
344  * The idle task, which as all tasks is implemented as a never ending loop.\r
345  * The idle task is automatically created and added to the ready lists upon\r
346  * creation of the first user task.\r
347  *\r
348  * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific\r
349  * language extensions.  The equivalent prototype for this function is:\r
350  *\r
351  * void prvIdleTask( void *pvParameters );\r
352  *\r
353  */\r
354 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );\r
355 \r
356 /*\r
357  * Utility to free all memory allocated by the scheduler to hold a TCB,\r
358  * including the stack pointed to by the TCB.\r
359  *\r
360  * This does not free memory allocated by the task itself (i.e. memory\r
361  * allocated by calls to pvPortMalloc from within the tasks application code).\r
362  */\r
363 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
364         static void prvDeleteTCB( tskTCB *pxTCB );\r
365 #endif\r
366 \r
367 /*\r
368  * Used only by the idle task.  This checks to see if anything has been placed\r
369  * in the list of tasks waiting to be deleted.  If so the task is cleaned up\r
370  * and its TCB deleted.\r
371  */\r
372 static void prvCheckTasksWaitingTermination( void );\r
373 \r
374 /*\r
375  * Allocates memory from the heap for a TCB and associated stack.  Checks the\r
376  * allocation was successful.\r
377  */\r
378 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );\r
379 \r
380 /*\r
381  * Called from vTaskList.  vListTasks details all the tasks currently under\r
382  * control of the scheduler.  The tasks may be in one of a number of lists.\r
383  * prvListTaskWithinSingleList accepts a list and details the tasks from\r
384  * within just that list.\r
385  *\r
386  * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM\r
387  * NORMAL APPLICATION CODE.\r
388  */\r
389 #if ( configUSE_TRACE_FACILITY == 1 )\r
390 \r
391         static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );\r
392 \r
393 #endif\r
394 \r
395 /*\r
396  * When a task is created, the stack of the task is filled with a known value.\r
397  * This function determines the 'high water mark' of the task stack by\r
398  * determining how much of the stack remains at the original preset value.\r
399  */\r
400 #if ( ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) )\r
401 \r
402         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte );\r
403 \r
404 #endif\r
405 \r
406 /*\r
407  * Checks that a task being resumed (unsuspended) is actually in the Suspended\r
408  * state.\r
409  */\r
410 #if ( INCLUDE_vTaskSuspend == 1 )\r
411 \r
412         static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB );  \r
413 \r
414 #endif\r
415 \r
416 /*lint +e956 */\r
417 \r
418 \r
419 \r
420 /*-----------------------------------------------------------\r
421  * TASK CREATION API documented in task.h\r
422  *----------------------------------------------------------*/\r
423 \r
424 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )\r
425 {\r
426 signed portBASE_TYPE xReturn;\r
427 tskTCB * pxNewTCB;\r
428 #if ( configUSE_TRACE_FACILITY == 1 )\r
429         static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */\r
430 #endif\r
431 \r
432         /* Allocate the memory required by the TCB and stack for the new task.\r
433         checking that the allocation was successful. */\r
434         pxNewTCB = prvAllocateTCBAndStack( usStackDepth );\r
435 \r
436         if( pxNewTCB != NULL )\r
437         {               \r
438                 portSTACK_TYPE *pxTopOfStack;\r
439 \r
440                 /* Setup the newly allocated TCB with the initial state of the task. */\r
441                 prvInitialiseTCBVariables( pxNewTCB, pcName, uxPriority );\r
442 \r
443                 /* Calculate the top of stack address.  This depends on whether the\r
444                 stack grows from high memory to low (as per the 80x86) or visa versa.\r
445                 portSTACK_GROWTH is used to make the result positive or negative as\r
446                 required by the port. */\r
447                 #if portSTACK_GROWTH < 0\r
448                 {\r
449                         pxTopOfStack = pxNewTCB->pxStack + ( usStackDepth - 1 );\r
450                 }\r
451                 #else\r
452                 {\r
453                         pxTopOfStack = pxNewTCB->pxStack;       \r
454                 }\r
455                 #endif\r
456 \r
457                 /* Initialize the TCB stack to look as if the task was already running,\r
458                 but had been interrupted by the scheduler.  The return address is set\r
459                 to the start of the task function. Once the stack has been initialised\r
460                 the     top of stack variable is updated. */\r
461                 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );\r
462 \r
463                 /* We are going to manipulate the task queues to add this task to a\r
464                 ready list, so must make sure no interrupts occur. */\r
465                 portENTER_CRITICAL();\r
466                 {\r
467                         uxCurrentNumberOfTasks++;\r
468                         if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )\r
469                         {\r
470                                 /* As this is the first task it must also be the current task. */\r
471                                 pxCurrentTCB =  pxNewTCB;\r
472 \r
473                                 /* This is the first task to be created so do the preliminary\r
474                                 initialisation required.  We will not recover if this call\r
475                                 fails, but we will report the failure. */\r
476                                 prvInitialiseTaskLists();\r
477                         }\r
478                         else\r
479                         {       \r
480                                 /* If the scheduler is not already running, make this task the\r
481                                 current task if it is the highest priority task to be created\r
482                                 so far. */\r
483                                 if( xSchedulerRunning == pdFALSE )\r
484                                 {\r
485                                         if( pxCurrentTCB->uxPriority <= uxPriority )\r
486                                         {\r
487                                                 pxCurrentTCB = pxNewTCB;        \r
488                                         }\r
489                                 }\r
490                         }                               \r
491 \r
492                         /* Remember the top priority to make context switching faster.  Use\r
493                         the priority in pxNewTCB as this has been capped to a valid value. */\r
494                         if( pxNewTCB->uxPriority > uxTopUsedPriority )\r
495                         {\r
496                                 uxTopUsedPriority = pxNewTCB->uxPriority;\r
497                         }\r
498 \r
499                         #if ( configUSE_TRACE_FACILITY == 1 )\r
500                         {\r
501                                 /* Add a counter into the TCB for tracing only. */\r
502                                 pxNewTCB->uxTCBNumber = uxTaskNumber;\r
503                                 uxTaskNumber++;\r
504                         }\r
505                         #endif\r
506 \r
507                         prvAddTaskToReadyQueue( pxNewTCB );\r
508 \r
509                         xReturn = pdPASS;\r
510                         traceTASK_CREATE( pxNewTCB );\r
511                 }\r
512                 portEXIT_CRITICAL();\r
513         }\r
514         else\r
515         {\r
516                 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;\r
517                 traceTASK_CREATE_FAILED( pxNewTCB );\r
518         }\r
519 \r
520         if( xReturn == pdPASS )\r
521         {\r
522                 if( ( void * ) pxCreatedTask != NULL )\r
523                 {\r
524                         /* Pass the TCB out - in an anonymous way.  The calling function/\r
525                         task can use this as a handle to delete the task later if\r
526                         required.*/\r
527                         *pxCreatedTask = ( xTaskHandle ) pxNewTCB;\r
528                 }\r
529 \r
530                 if( xSchedulerRunning != pdFALSE )\r
531                 {\r
532                         /* If the created task is of a higher priority than the current task\r
533                         then it should run now. */\r
534                         if( pxCurrentTCB->uxPriority < uxPriority )\r
535                         {\r
536                                 taskYIELD();\r
537                         }\r
538                 }\r
539         }\r
540 \r
541         return xReturn;\r
542 }\r
543 /*-----------------------------------------------------------*/\r
544 \r
545 #if ( INCLUDE_vTaskDelete == 1 )\r
546 \r
547         void vTaskDelete( xTaskHandle pxTaskToDelete )\r
548         {\r
549         tskTCB *pxTCB;\r
550 \r
551                 taskENTER_CRITICAL();\r
552                 {\r
553                         /* Ensure a yield is performed if the current task is being\r
554                         deleted. */\r
555                         if( pxTaskToDelete == pxCurrentTCB )\r
556                         {\r
557                                 pxTaskToDelete = NULL;\r
558                         }\r
559 \r
560                         /* If null is passed in here then we are deleting ourselves. */\r
561                         pxTCB = prvGetTCBFromHandle( pxTaskToDelete );\r
562 \r
563                         traceTASK_DELETE( pxTCB );\r
564 \r
565                         /* Remove task from the ready list and place in the     termination list.\r
566                         This will stop the task from be scheduled.  The idle task will check\r
567                         the termination list and free up any memory allocated by the\r
568                         scheduler for the TCB and stack. */\r
569                         vListRemove( &( pxTCB->xGenericListItem ) );\r
570 \r
571                         /* Is the task waiting on an event also? */                                                                                             \r
572                         if( pxTCB->xEventListItem.pvContainer )\r
573                         {\r
574                                 vListRemove( &( pxTCB->xEventListItem ) );\r
575                         }\r
576 \r
577                         vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );\r
578 \r
579                         /* Increment the ucTasksDeleted variable so the idle task knows\r
580                         there is a task that has been deleted and that it should therefore\r
581                         check the xTasksWaitingTermination list. */\r
582                         ++uxTasksDeleted;\r
583                 }\r
584                 taskEXIT_CRITICAL();\r
585 \r
586                 /* Force a reschedule if we have just deleted the current task. */\r
587                 if( xSchedulerRunning != pdFALSE )\r
588                 {\r
589                         if( ( void * ) pxTaskToDelete == NULL )\r
590                         {\r
591                                 taskYIELD();\r
592                         }\r
593                 }\r
594         }\r
595 \r
596 #endif\r
597 \r
598 \r
599 \r
600 \r
601 \r
602 \r
603 /*-----------------------------------------------------------\r
604  * TASK CONTROL API documented in task.h\r
605  *----------------------------------------------------------*/\r
606 \r
607 #if ( INCLUDE_vTaskDelayUntil == 1 )\r
608 \r
609         void vTaskDelayUntil( portTickType * const pxPreviousWakeTime, portTickType xTimeIncrement )\r
610         {\r
611         portTickType xTimeToWake;\r
612         portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;\r
613 \r
614                 vTaskSuspendAll();\r
615                 {\r
616                         /* Generate the tick time at which the task wants to wake. */\r
617                         xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;\r
618 \r
619                         if( xTickCount < *pxPreviousWakeTime )\r
620                         {\r
621                                 /* The tick count has overflowed since this function was\r
622                                 lasted called.  In this case the only time we should ever\r
623                                 actually delay is if the wake time has also     overflowed,\r
624                                 and the wake time is greater than the tick time.  When this\r
625                                 is the case it is as if neither time had overflowed. */\r
626                                 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )\r
627                                 {\r
628                                         xShouldDelay = pdTRUE;\r
629                                 }\r
630                         }\r
631                         else\r
632                         {\r
633                                 /* The tick time has not overflowed.  In this case we will\r
634                                 delay if either the wake time has overflowed, and/or the\r
635                                 tick time is less than the wake time. */\r
636                                 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )\r
637                                 {\r
638                                         xShouldDelay = pdTRUE;\r
639                                 }\r
640                         }\r
641 \r
642                         /* Update the wake time ready for the next call. */\r
643                         *pxPreviousWakeTime = xTimeToWake;\r
644 \r
645                         if( xShouldDelay )\r
646                         {\r
647                                 traceTASK_DELAY_UNTIL();\r
648 \r
649                                 /* We must remove ourselves from the ready list before adding\r
650                                 ourselves to the blocked list as the same list item is used for\r
651                                 both lists. */\r
652                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
653 \r
654                                 /* The list item will be inserted in wake time order. */\r
655                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
656 \r
657                                 if( xTimeToWake < xTickCount )\r
658                                 {\r
659                                         /* Wake time has overflowed.  Place this item in the\r
660                                         overflow list. */\r
661                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
662                                 }\r
663                                 else\r
664                                 {\r
665                                         /* The wake time has not overflowed, so we can use the\r
666                                         current block list. */\r
667                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
668                                 }\r
669                         }\r
670                 }\r
671                 xAlreadyYielded = xTaskResumeAll();\r
672 \r
673                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
674                 have put ourselves to sleep. */\r
675                 if( !xAlreadyYielded )\r
676                 {\r
677                         taskYIELD();\r
678                 }\r
679         }       \r
680         \r
681 #endif\r
682 /*-----------------------------------------------------------*/\r
683 \r
684 #if ( INCLUDE_vTaskDelay == 1 )\r
685 \r
686         void vTaskDelay( portTickType xTicksToDelay )\r
687         {\r
688         portTickType xTimeToWake;\r
689         signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
690 \r
691                 /* A delay time of zero just forces a reschedule. */\r
692                 if( xTicksToDelay > ( portTickType ) 0 )\r
693                 {\r
694                         vTaskSuspendAll();\r
695                         {\r
696                                 traceTASK_DELAY();\r
697 \r
698                                 /* A task that is removed from the event list while the\r
699                                 scheduler is suspended will not get placed in the ready\r
700                                 list or removed from the blocked list until the scheduler\r
701                                 is resumed.\r
702                                 \r
703                                 This task cannot be in an event list as it is the currently\r
704                                 executing task. */\r
705 \r
706                                 /* Calculate the time to wake - this may overflow but this is\r
707                                 not a problem. */\r
708                                 xTimeToWake = xTickCount + xTicksToDelay;\r
709 \r
710                                 /* We must remove ourselves from the ready list before adding\r
711                                 ourselves to the blocked list as the same list item is used for\r
712                                 both lists. */\r
713                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
714 \r
715                                 /* The list item will be inserted in wake time order. */\r
716                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
717 \r
718                                 if( xTimeToWake < xTickCount )\r
719                                 {\r
720                                         /* Wake time has overflowed.  Place this item in the\r
721                                         overflow list. */\r
722                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
723                                 }\r
724                                 else\r
725                                 {\r
726                                         /* The wake time has not overflowed, so we can use the\r
727                                         current block list. */\r
728                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
729                                 }\r
730                         }\r
731                         xAlreadyYielded = xTaskResumeAll();\r
732                 }\r
733                 \r
734                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
735                 have put ourselves to sleep. */\r
736                 if( !xAlreadyYielded )\r
737                 {\r
738                         taskYIELD();\r
739                 }\r
740         }\r
741         \r
742 #endif\r
743 /*-----------------------------------------------------------*/\r
744 \r
745 #if ( INCLUDE_uxTaskPriorityGet == 1 )\r
746 \r
747         unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )\r
748         {\r
749         tskTCB *pxTCB;\r
750         unsigned portBASE_TYPE uxReturn;\r
751 \r
752                 taskENTER_CRITICAL();\r
753                 {\r
754                         /* If null is passed in here then we are changing the\r
755                         priority of the calling function. */\r
756                         pxTCB = prvGetTCBFromHandle( pxTask );\r
757                         uxReturn = pxTCB->uxPriority;\r
758                 }\r
759                 taskEXIT_CRITICAL();\r
760 \r
761                 return uxReturn;\r
762         }\r
763 \r
764 #endif\r
765 /*-----------------------------------------------------------*/\r
766 \r
767 #if ( INCLUDE_vTaskPrioritySet == 1 )\r
768 \r
769         void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )\r
770         {\r
771         tskTCB *pxTCB;\r
772         unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;\r
773 \r
774                 /* Ensure the new priority is valid. */\r
775                 if( uxNewPriority >= configMAX_PRIORITIES )\r
776                 {\r
777                         uxNewPriority = configMAX_PRIORITIES - 1;\r
778                 }\r
779 \r
780                 taskENTER_CRITICAL();\r
781                 {\r
782                         /* If null is passed in here then we are changing the\r
783                         priority of the calling function. */\r
784                         pxTCB = prvGetTCBFromHandle( pxTask );\r
785                         \r
786                         traceTASK_PRIORITY_SET( pxTask, uxNewPriority );\r
787 \r
788                         #if ( configUSE_MUTEXES == 1 )\r
789                         {\r
790                                 uxCurrentPriority = pxTCB->uxBasePriority;\r
791                         }\r
792                         #else\r
793                         {\r
794                                 uxCurrentPriority = pxTCB->uxPriority;\r
795                         }\r
796                         #endif\r
797 \r
798                         if( uxCurrentPriority != uxNewPriority )\r
799                         {\r
800                                 /* The priority change may have readied a task of higher\r
801                                 priority than the calling task. */\r
802                                 if( uxNewPriority > uxCurrentPriority )\r
803                                 {\r
804                                         if( pxTask != NULL )\r
805                                         {\r
806                                                 /* The priority of another task is being raised.  If we\r
807                                                 were raising the priority of the currently running task\r
808                                                 there would be no need to switch as it must have already\r
809                                                 been the highest priority task. */\r
810                                                 xYieldRequired = pdTRUE;\r
811                                         }\r
812                                 }\r
813                                 else if( pxTask == NULL )\r
814                                 {\r
815                                         /* Setting our own priority down means there may now be another\r
816                                         task of higher priority that is ready to execute. */\r
817                                         xYieldRequired = pdTRUE;\r
818                                 }\r
819                         \r
820                                 \r
821 \r
822                                 #if ( configUSE_MUTEXES == 1 )\r
823                                 {\r
824                                         /* Only change the priority being used if the task is not\r
825                                         currently using an inherited priority. */\r
826                                         if( pxTCB->uxBasePriority == pxTCB->uxPriority )\r
827                                         {\r
828                                                 pxTCB->uxPriority = uxNewPriority;\r
829                                         }\r
830                                         \r
831                                         /* The base priority gets set whatever. */\r
832                                         pxTCB->uxBasePriority = uxNewPriority;                                  \r
833                                 }\r
834                                 #else\r
835                                 {\r
836                                         pxTCB->uxPriority = uxNewPriority;\r
837                                 }\r
838                                 #endif\r
839 \r
840                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), ( configMAX_PRIORITIES - ( portTickType ) uxNewPriority ) );\r
841 \r
842                                 /* If the task is in the blocked or suspended list we need do\r
843                                 nothing more than change it's priority variable. However, if\r
844                                 the task is in a ready list it needs to be removed and placed\r
845                                 in the queue appropriate to its new priority. */\r
846                                 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
847                                 {\r
848                                         /* The task is currently in its ready list - remove before adding\r
849                                         it to it's new ready list.  As we are in a critical section we\r
850                                         can do this even if the scheduler is suspended. */\r
851                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
852                                         prvAddTaskToReadyQueue( pxTCB );\r
853                                 }                       \r
854                                 \r
855                                 if( xYieldRequired == pdTRUE )\r
856                                 {\r
857                                         taskYIELD();\r
858                                 }                               \r
859                         }\r
860                 }\r
861                 taskEXIT_CRITICAL();\r
862         }\r
863 \r
864 #endif\r
865 /*-----------------------------------------------------------*/\r
866 \r
867 #if ( INCLUDE_vTaskSuspend == 1 )\r
868 \r
869         void vTaskSuspend( xTaskHandle pxTaskToSuspend )\r
870         {\r
871         tskTCB *pxTCB;\r
872 \r
873                 taskENTER_CRITICAL();\r
874                 {\r
875                         /* Ensure a yield is performed if the current task is being\r
876                         suspended. */\r
877                         if( pxTaskToSuspend == pxCurrentTCB )\r
878                         {\r
879                                 pxTaskToSuspend = NULL;\r
880                         }\r
881 \r
882                         /* If null is passed in here then we are suspending ourselves. */\r
883                         pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );\r
884 \r
885                         traceTASK_SUSPEND( pxTaskToSuspend );\r
886 \r
887                         /* Remove task from the ready/delayed list and place in the     suspended list. */\r
888                         vListRemove( &( pxTCB->xGenericListItem ) );\r
889 \r
890                         /* Is the task waiting on an event also? */                                                                                             \r
891                         if( pxTCB->xEventListItem.pvContainer )\r
892                         {\r
893                                 vListRemove( &( pxTCB->xEventListItem ) );\r
894                         }\r
895 \r
896                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );\r
897                 }\r
898                 taskEXIT_CRITICAL();\r
899 \r
900                 /* We may have just suspended the current task. */\r
901                 if( ( void * ) pxTaskToSuspend == NULL )\r
902                 {\r
903                         taskYIELD();\r
904                 }\r
905         }\r
906 \r
907 #endif\r
908 /*-----------------------------------------------------------*/\r
909 \r
910 #if ( INCLUDE_vTaskSuspend == 1 )\r
911 \r
912         static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB )\r
913         {\r
914         portBASE_TYPE xReturn = pdFALSE;\r
915 \r
916                 /* Is the task we are attempting to resume actually in the\r
917                 suspended list? */\r
918                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
919                 {\r
920                         /* Has the task already been resumed from within an ISR? */\r
921                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
922                         {                       \r
923                                 /* Is it in the suspended list because it is in the\r
924                                 Suspended state?  It is possible to be in the suspended\r
925                                 list because it is blocked on a task with no timeout\r
926                                 specified. */\r
927                                 if( listIS_CONTAINED_WITHIN( NULL, &( pxTCB->xEventListItem ) ) == pdTRUE )\r
928                                 {\r
929                                         xReturn = pdTRUE;\r
930                                 }\r
931                         }\r
932                 }\r
933 \r
934                 return xReturn;\r
935         }\r
936 \r
937 #endif\r
938 /*-----------------------------------------------------------*/\r
939 \r
940 #if ( INCLUDE_vTaskSuspend == 1 )\r
941 \r
942         void vTaskResume( xTaskHandle pxTaskToResume )\r
943         {\r
944         tskTCB *pxTCB;\r
945 \r
946                 /* Remove the task from whichever list it is currently in, and place\r
947                 it in the ready list. */\r
948                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
949 \r
950                 /* The parameter cannot be NULL as it is impossible to resume the\r
951                 currently executing task. */\r
952                 if( pxTCB != NULL )\r
953                 {\r
954                         taskENTER_CRITICAL();\r
955                         {\r
956                                 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )\r
957                                 {\r
958                                         traceTASK_RESUME( pxTCB );\r
959 \r
960                                         /* As we are in a critical section we can access the ready\r
961                                         lists even if the scheduler is suspended. */\r
962                                         vListRemove(  &( pxTCB->xGenericListItem ) );\r
963                                         prvAddTaskToReadyQueue( pxTCB );\r
964 \r
965                                         /* We may have just resumed a higher priority task. */\r
966                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
967                                         {\r
968                                                 /* This yield may not cause the task just resumed to run, but\r
969                                                 will leave the lists in the correct state for the next yield. */\r
970                                                 taskYIELD();\r
971                                         }\r
972                                 }\r
973                         }\r
974                         taskEXIT_CRITICAL();\r
975                 }\r
976         }\r
977 \r
978 #endif\r
979 \r
980 /*-----------------------------------------------------------*/\r
981 \r
982 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
983 \r
984         portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )\r
985         {\r
986         portBASE_TYPE xYieldRequired = pdFALSE;\r
987         tskTCB *pxTCB;\r
988 \r
989                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
990 \r
991                 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )\r
992                 {\r
993                         traceTASK_RESUME_FROM_ISR( pxTCB );\r
994 \r
995                         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
996                         {\r
997                                 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );\r
998                                 vListRemove(  &( pxTCB->xGenericListItem ) );   \r
999                                 prvAddTaskToReadyQueue( pxTCB );\r
1000                         }\r
1001                         else\r
1002                         {\r
1003                                 /* We cannot access the delayed or ready lists, so will hold this\r
1004                                 task pending until the scheduler is resumed, at which point a\r
1005                                 yield will be performed if necessary. */\r
1006                                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );\r
1007                         }\r
1008                 }\r
1009 \r
1010                 return xYieldRequired;\r
1011         }\r
1012 \r
1013 #endif\r
1014 \r
1015 \r
1016 \r
1017 \r
1018 /*-----------------------------------------------------------\r
1019  * PUBLIC SCHEDULER CONTROL documented in task.h\r
1020  *----------------------------------------------------------*/\r
1021 \r
1022 \r
1023 void vTaskStartScheduler( void )\r
1024 {\r
1025 portBASE_TYPE xReturn;\r
1026 \r
1027         /* Add the idle task at the lowest priority. */\r
1028         xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );\r
1029 \r
1030         if( xReturn == pdPASS )\r
1031         {\r
1032                 /* Interrupts are turned off here, to ensure a tick does not occur\r
1033                 before or during the call to xPortStartScheduler().  The stacks of\r
1034                 the created tasks contain a status word with interrupts switched on\r
1035                 so interrupts will automatically get re-enabled when the first task\r
1036                 starts to run.\r
1037                 \r
1038                 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE\r
1039                 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */\r
1040                 portDISABLE_INTERRUPTS();\r
1041 \r
1042                 xSchedulerRunning = pdTRUE;\r
1043                 xTickCount = ( portTickType ) 0;\r
1044 \r
1045                 /* Setting up the timer tick is hardware specific and thus in the\r
1046                 portable interface. */\r
1047                 if( xPortStartScheduler() )\r
1048                 {\r
1049                         /* Should not reach here as if the scheduler is running the\r
1050                         function will not return. */\r
1051                 }\r
1052                 else\r
1053                 {\r
1054                         /* Should only reach here if a task calls xTaskEndScheduler(). */\r
1055                 }\r
1056         }\r
1057 }\r
1058 /*-----------------------------------------------------------*/\r
1059 \r
1060 void vTaskEndScheduler( void )\r
1061 {\r
1062         /* Stop the scheduler interrupts and call the portable scheduler end\r
1063         routine so the original ISRs can be restored if necessary.  The port\r
1064         layer must ensure interrupts enable     bit is left in the correct state. */\r
1065         portDISABLE_INTERRUPTS();\r
1066         xSchedulerRunning = pdFALSE;\r
1067         vPortEndScheduler();\r
1068 }\r
1069 /*----------------------------------------------------------*/\r
1070 \r
1071 void vTaskSuspendAll( void )\r
1072 {\r
1073         portENTER_CRITICAL();\r
1074                 ++uxSchedulerSuspended;\r
1075         portEXIT_CRITICAL();\r
1076 }\r
1077 /*----------------------------------------------------------*/\r
1078 \r
1079 signed portBASE_TYPE xTaskResumeAll( void )\r
1080 {\r
1081 register tskTCB *pxTCB;\r
1082 signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
1083 \r
1084         /* It is possible that an ISR caused a task to be removed from an event\r
1085         list while the scheduler was suspended.  If this was the case then the\r
1086         removed task will have been added to the xPendingReadyList.  Once the\r
1087         scheduler has been resumed it is safe to move all the pending ready\r
1088         tasks from this list into their appropriate ready list. */\r
1089         portENTER_CRITICAL();\r
1090         {\r
1091                 --uxSchedulerSuspended;\r
1092 \r
1093                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1094                 {                       \r
1095                         if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )\r
1096                         {\r
1097                                 portBASE_TYPE xYieldRequired = pdFALSE;\r
1098                                 \r
1099                                 /* Move any readied tasks from the pending list into the\r
1100                                 appropriate ready list. */\r
1101                                 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY(  ( ( xList * ) &xPendingReadyList ) ) ) != NULL )\r
1102                                 {\r
1103                                         vListRemove( &( pxTCB->xEventListItem ) );\r
1104                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1105                                         prvAddTaskToReadyQueue( pxTCB );\r
1106                                         \r
1107                                         /* If we have moved a task that has a priority higher than\r
1108                                         the current task then we should yield. */\r
1109                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1110                                         {\r
1111                                                 xYieldRequired = pdTRUE;\r
1112                                         }\r
1113                                 }\r
1114 \r
1115                                 /* If any ticks occurred while the scheduler was suspended then\r
1116                                 they should be processed now.  This ensures the tick count does not\r
1117                                 slip, and that any delayed tasks are resumed at the correct time. */\r
1118                                 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1119                                 {\r
1120                                         while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1121                                         {\r
1122                                                 vTaskIncrementTick();\r
1123                                                 --uxMissedTicks;\r
1124                                         }\r
1125 \r
1126                                         /* As we have processed some ticks it is appropriate to yield\r
1127                                         to ensure the highest priority task that is ready to run is\r
1128                                         the task actually running. */\r
1129                                         #if configUSE_PREEMPTION == 1\r
1130                                         {\r
1131                                                 xYieldRequired = pdTRUE;\r
1132                                         }\r
1133                                         #endif\r
1134                                 }\r
1135                                 \r
1136                                 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )\r
1137                                 {\r
1138                                         xAlreadyYielded = pdTRUE;\r
1139                                         xMissedYield = pdFALSE;\r
1140                                         taskYIELD();\r
1141                                 }\r
1142                         }\r
1143                 }\r
1144         }\r
1145         portEXIT_CRITICAL();\r
1146 \r
1147         return xAlreadyYielded;\r
1148 }\r
1149 \r
1150 \r
1151 \r
1152 \r
1153 \r
1154 \r
1155 /*-----------------------------------------------------------\r
1156  * PUBLIC TASK UTILITIES documented in task.h\r
1157  *----------------------------------------------------------*/\r
1158 \r
1159 \r
1160 \r
1161 portTickType xTaskGetTickCount( void )\r
1162 {\r
1163 portTickType xTicks;\r
1164 \r
1165         /* Critical section required if running on a 16 bit processor. */\r
1166         taskENTER_CRITICAL();\r
1167         {\r
1168                 xTicks = xTickCount;\r
1169         }\r
1170         taskEXIT_CRITICAL();\r
1171 \r
1172         return xTicks;\r
1173 }\r
1174 /*-----------------------------------------------------------*/\r
1175 \r
1176 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )\r
1177 {\r
1178 unsigned portBASE_TYPE uxNumberOfTasks;\r
1179 \r
1180         taskENTER_CRITICAL();\r
1181                 uxNumberOfTasks = uxCurrentNumberOfTasks;\r
1182         taskEXIT_CRITICAL();\r
1183 \r
1184         return uxNumberOfTasks;\r
1185 }\r
1186 /*-----------------------------------------------------------*/\r
1187 \r
1188 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1189 \r
1190         void vTaskList( signed portCHAR *pcWriteBuffer )\r
1191         {\r
1192         unsigned portBASE_TYPE uxQueue;\r
1193 \r
1194                 /* This is a VERY costly function that should be used for debug only.\r
1195                 It leaves interrupts disabled for a LONG time. */\r
1196 \r
1197         vTaskSuspendAll();\r
1198                 {\r
1199                         /* Run through all the lists that could potentially contain a TCB and\r
1200                         report the task name, state and stack high water mark. */\r
1201 \r
1202                         pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;\r
1203                         strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );\r
1204 \r
1205                         uxQueue = uxTopUsedPriority + 1;\r
1206 \r
1207                         do\r
1208                         {\r
1209                                 uxQueue--;\r
1210 \r
1211                                 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )\r
1212                                 {\r
1213                                         prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );                     \r
1214                                 }\r
1215                         }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1216 \r
1217                         if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )\r
1218                         {\r
1219                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );\r
1220                         }\r
1221 \r
1222                         if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )\r
1223                         {\r
1224                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );\r
1225                         }\r
1226 \r
1227                         if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )\r
1228                         {\r
1229                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );\r
1230                         }\r
1231 \r
1232                         if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1233                         {\r
1234                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );\r
1235                         }\r
1236                 }\r
1237         xTaskResumeAll();\r
1238         }\r
1239 \r
1240 #endif\r
1241 /*----------------------------------------------------------*/\r
1242 \r
1243 #if ( configUSE_TRACE_FACILITY == 1 )\r
1244 \r
1245         void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )\r
1246         {\r
1247                 portENTER_CRITICAL();\r
1248                 {\r
1249                         pcTraceBuffer = ( signed portCHAR * )pcBuffer;\r
1250                         pcTraceBufferStart = pcBuffer;\r
1251                         pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );\r
1252                         xTracing = pdTRUE;\r
1253                 }\r
1254                 portEXIT_CRITICAL();\r
1255         }\r
1256 \r
1257 #endif\r
1258 /*----------------------------------------------------------*/\r
1259 \r
1260 #if ( configUSE_TRACE_FACILITY == 1 )\r
1261 \r
1262         unsigned portLONG ulTaskEndTrace( void )\r
1263         {\r
1264         unsigned portLONG ulBufferLength;\r
1265 \r
1266                 portENTER_CRITICAL();\r
1267                         xTracing = pdFALSE;\r
1268                 portEXIT_CRITICAL();\r
1269 \r
1270                 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );\r
1271 \r
1272                 return ulBufferLength;\r
1273         }\r
1274 \r
1275 #endif\r
1276 \r
1277 \r
1278 \r
1279 /*-----------------------------------------------------------\r
1280  * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES\r
1281  * documented in task.h\r
1282  *----------------------------------------------------------*/\r
1283 \r
1284 \r
1285 inline void vTaskIncrementTick( void )\r
1286 {\r
1287         /* Called by the portable layer each time a tick interrupt occurs.\r
1288         Increments the tick then checks to see if the new tick value will cause any\r
1289         tasks to be unblocked. */\r
1290         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1291         {\r
1292                 ++xTickCount;\r
1293                 if( xTickCount == ( portTickType ) 0 )\r
1294                 {\r
1295                         xList *pxTemp;\r
1296 \r
1297                         /* Tick count has overflowed so we need to swap the delay lists.\r
1298                         If there are any items in pxDelayedTaskList here then there is\r
1299                         an error! */\r
1300                         pxTemp = pxDelayedTaskList;\r
1301                         pxDelayedTaskList = pxOverflowDelayedTaskList;\r
1302                         pxOverflowDelayedTaskList = pxTemp;\r
1303             xNumOfOverflows++;\r
1304                 }\r
1305 \r
1306                 /* See if this tick has made a timeout expire. */\r
1307                 prvCheckDelayedTasks();\r
1308         }\r
1309         else\r
1310         {\r
1311                 ++uxMissedTicks;\r
1312 \r
1313                 /* The tick hook gets called at regular intervals, even if the\r
1314                 scheduler is locked. */\r
1315                 #if ( configUSE_TICK_HOOK == 1 )\r
1316                 {\r
1317                         extern void vApplicationTickHook( void );\r
1318 \r
1319                         vApplicationTickHook();\r
1320                 }\r
1321                 #endif\r
1322         }\r
1323 \r
1324         #if ( configUSE_TICK_HOOK == 1 )\r
1325         {\r
1326                 extern void vApplicationTickHook( void );\r
1327 \r
1328                 /* Guard against the tick hook being called when the missed tick\r
1329                 count is being unwound (when the scheduler is being unlocked. */\r
1330                 if( uxMissedTicks == 0 )\r
1331                 {\r
1332                         vApplicationTickHook();\r
1333                 }\r
1334         }\r
1335         #endif\r
1336 \r
1337         traceTASK_INCREMENT_TICK( xTickCount );\r
1338 }\r
1339 /*-----------------------------------------------------------*/\r
1340 \r
1341 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1342 \r
1343         void vTaskCleanUpResources( void )\r
1344         {\r
1345         unsigned portSHORT usQueue;\r
1346         volatile tskTCB *pxTCB;\r
1347 \r
1348                 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;\r
1349 \r
1350                 /* Remove any TCB's from the ready queues. */\r
1351                 do\r
1352                 {\r
1353                         usQueue--;\r
1354 \r
1355                         while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )\r
1356                         {\r
1357                                 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );\r
1358                                 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1359 \r
1360                                 prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1361                         }\r
1362                 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1363 \r
1364                 /* Remove any TCB's from the delayed queue. */\r
1365                 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )\r
1366                 {\r
1367                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );\r
1368                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1369 \r
1370                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1371                 }\r
1372 \r
1373                 /* Remove any TCB's from the overflow delayed queue. */\r
1374                 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )\r
1375                 {\r
1376                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );\r
1377                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1378 \r
1379                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1380                 }\r
1381 \r
1382                 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1383                 {\r
1384                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );\r
1385                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1386 \r
1387                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1388                 }               \r
1389         }\r
1390 \r
1391 #endif\r
1392 /*-----------------------------------------------------------*/\r
1393 \r
1394 #if ( configUSE_APPLICATION_TASK_TAG == 1 )\r
1395 \r
1396         void vTaskSetApplicationTaskTag( xTaskHandle xTask, pdTASK_HOOK_CODE pxTagValue )\r
1397         {\r
1398         tskTCB *xTCB;\r
1399 \r
1400                 /* If xTask is NULL then we are setting our own task hook. */\r
1401                 if( xTask == NULL )\r
1402                 {\r
1403                         xTCB = ( tskTCB * ) pxCurrentTCB;\r
1404                 }\r
1405                 else\r
1406                 {\r
1407                         xTCB = ( tskTCB * ) xTask;\r
1408                 }\r
1409                 \r
1410                 /* Save the hook function in the TCB. */\r
1411                 portENTER_CRITICAL();\r
1412                         xTCB->pxTaskTag = pxTagValue;\r
1413                 portEXIT_CRITICAL();\r
1414         }\r
1415         \r
1416 #endif\r
1417 /*-----------------------------------------------------------*/\r
1418 \r
1419 #if ( configUSE_APPLICATION_TASK_TAG == 1 )\r
1420 \r
1421         portBASE_TYPE xTaskCallApplicationTaskHook( xTaskHandle xTask, void *pvParameter )\r
1422         {\r
1423         tskTCB *xTCB;\r
1424         portBASE_TYPE xReturn;\r
1425 \r
1426                 /* If xTask is NULL then we are calling our own task hook. */\r
1427                 if( xTask == NULL )\r
1428                 {\r
1429                         xTCB = ( tskTCB * ) pxCurrentTCB;\r
1430                 }\r
1431                 else\r
1432                 {\r
1433                         xTCB = ( tskTCB * ) xTask;\r
1434                 }\r
1435 \r
1436                 if( xTCB->pxTaskTag != NULL )\r
1437                 {\r
1438                         xReturn = xTCB->pxTaskTag( pvParameter );\r
1439                 }\r
1440                 else\r
1441                 {\r
1442                         xReturn = pdFAIL;\r
1443                 }\r
1444 \r
1445                 return xReturn;\r
1446         }\r
1447         \r
1448 #endif\r
1449 /*-----------------------------------------------------------*/\r
1450 \r
1451 void vTaskSwitchContext( void )\r
1452 {\r
1453         traceTASK_SWITCHED_OUT();\r
1454 \r
1455         if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )\r
1456         {\r
1457                 /* The scheduler is currently suspended - do not allow a context\r
1458                 switch. */\r
1459                 xMissedYield = pdTRUE;\r
1460                 return;\r
1461         }\r
1462 \r
1463         taskCHECK_FOR_STACK_OVERFLOW();\r
1464 \r
1465         /* Find the highest priority queue that contains ready tasks. */\r
1466         while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )\r
1467         {\r
1468                 --uxTopReadyPriority;\r
1469         }\r
1470 \r
1471         /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the\r
1472         same priority get an equal share of the processor time. */\r
1473         listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );\r
1474 \r
1475         traceTASK_SWITCHED_IN();\r
1476         vWriteTraceToBuffer();\r
1477 }\r
1478 /*-----------------------------------------------------------*/\r
1479 \r
1480 void vTaskPlaceOnEventList( const xList * const pxEventList, portTickType xTicksToWait )\r
1481 {\r
1482 portTickType xTimeToWake;\r
1483 \r
1484         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1485         SCHEDULER SUSPENDED. */\r
1486 \r
1487         /* Place the event list item of the TCB in the appropriate event list.\r
1488         This is placed in the list in priority order so the highest priority task\r
1489         is the first to be woken by the event. */\r
1490         vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );\r
1491 \r
1492         /* We must remove ourselves from the ready list before adding ourselves\r
1493         to the blocked list as the same list item is used for both lists.  We have\r
1494         exclusive access to the ready lists as the scheduler is locked. */\r
1495         vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1496 \r
1497 \r
1498         #if ( INCLUDE_vTaskSuspend == 1 )\r
1499         {                       \r
1500                 if( xTicksToWait == portMAX_DELAY )\r
1501                 {\r
1502                         /* Add ourselves to the suspended task list instead of a delayed task\r
1503                         list to ensure we are not woken by a timing event.  We will block\r
1504                         indefinitely. */\r
1505                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1506                 }\r
1507                 else\r
1508                 {\r
1509                         /* Calculate the time at which the task should be woken if the event does\r
1510                         not occur.  This may overflow but this doesn't matter. */\r
1511                         xTimeToWake = xTickCount + xTicksToWait;\r
1512                 \r
1513                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1514                 \r
1515                         if( xTimeToWake < xTickCount )\r
1516                         {\r
1517                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1518                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1519                         }\r
1520                         else\r
1521                         {\r
1522                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1523                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1524                         }\r
1525                 }\r
1526         }\r
1527         #else\r
1528         {\r
1529                         /* Calculate the time at which the task should be woken if the event does\r
1530                         not occur.  This may overflow but this doesn't matter. */\r
1531                         xTimeToWake = xTickCount + xTicksToWait;\r
1532                 \r
1533                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1534                 \r
1535                         if( xTimeToWake < xTickCount )\r
1536                         {\r
1537                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1538                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1539                         }\r
1540                         else\r
1541                         {\r
1542                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1543                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1544                         }\r
1545         }\r
1546         #endif\r
1547 }\r
1548 /*-----------------------------------------------------------*/\r
1549 \r
1550 signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList )\r
1551 {\r
1552 tskTCB *pxUnblockedTCB;\r
1553 portBASE_TYPE xReturn;\r
1554 \r
1555         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1556         SCHEDULER SUSPENDED.  It can also be called from within an ISR. */\r
1557 \r
1558         /* The event list is sorted in priority order, so we can remove the\r
1559         first in the list, remove the TCB from the delayed list, and add\r
1560         it to the ready list.\r
1561         \r
1562         If an event is for a queue that is locked then this function will never\r
1563         get called - the lock count on the queue will get modified instead.  This\r
1564         means we can always expect exclusive access to the event list here. */\r
1565         pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );\r
1566         vListRemove( &( pxUnblockedTCB->xEventListItem ) );\r
1567 \r
1568         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1569         {\r
1570                 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );\r
1571                 prvAddTaskToReadyQueue( pxUnblockedTCB );\r
1572         }\r
1573         else\r
1574         {\r
1575                 /* We cannot access the delayed or ready lists, so will hold this\r
1576                 task pending until the scheduler is resumed. */\r
1577                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );\r
1578         }\r
1579 \r
1580         if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1581         {\r
1582                 /* Return true if the task removed from the event list has\r
1583                 a higher priority than the calling task.  This allows\r
1584                 the calling task to know if it should force a context\r
1585                 switch now. */\r
1586                 xReturn = pdTRUE;\r
1587         }\r
1588         else\r
1589         {\r
1590                 xReturn = pdFALSE;\r
1591         }\r
1592 \r
1593         return xReturn;\r
1594 }\r
1595 /*-----------------------------------------------------------*/\r
1596 \r
1597 void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut )\r
1598 {\r
1599     pxTimeOut->xOverflowCount = xNumOfOverflows;\r
1600     pxTimeOut->xTimeOnEntering = xTickCount;\r
1601 }\r
1602 /*-----------------------------------------------------------*/\r
1603 \r
1604 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait )\r
1605 {\r
1606 portBASE_TYPE xReturn;\r
1607 \r
1608         portENTER_CRITICAL();\r
1609         {\r
1610                 #if ( INCLUDE_vTaskSuspend == 1 )\r
1611                         /* If INCLUDE_vTaskSuspend is set to 1 and the block time specified is\r
1612                         the maximum block time then the task should block indefinitely, and\r
1613                         therefore never time out. */\r
1614                         if( *pxTicksToWait == portMAX_DELAY )\r
1615                         {\r
1616                                 xReturn = pdFALSE;\r
1617                         }\r
1618                         else /* We are not blocking indefinitely, perform the checks below. */\r
1619                 #endif\r
1620 \r
1621                 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )\r
1622                 {\r
1623                         /* The tick count is greater than the time at which vTaskSetTimeout()\r
1624                         was called, but has also overflowed since vTaskSetTimeOut() was called.\r
1625                         It must have wrapped all the way around and gone past us again. This\r
1626                         passed since vTaskSetTimeout() was called. */\r
1627                         xReturn = pdTRUE;\r
1628                 }\r
1629                 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )\r
1630                 {\r
1631                         /* Not a genuine timeout. Adjust parameters for time remaining. */\r
1632                         *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );\r
1633                         vTaskSetTimeOutState( pxTimeOut );\r
1634                         xReturn = pdFALSE;\r
1635                 }\r
1636                 else\r
1637                 {\r
1638                         xReturn = pdTRUE;\r
1639                 }\r
1640         }\r
1641         portEXIT_CRITICAL();\r
1642 \r
1643     return xReturn;\r
1644 }\r
1645 /*-----------------------------------------------------------*/\r
1646 \r
1647 void vTaskMissedYield( void )\r
1648 {\r
1649         xMissedYield = pdTRUE;\r
1650 }\r
1651 \r
1652 /*\r
1653  * -----------------------------------------------------------\r
1654  * The Idle task.\r
1655  * ----------------------------------------------------------\r
1656  *\r
1657  * The portTASK_FUNCTION() macro is used to allow port/compiler specific\r
1658  * language extensions.  The equivalent prototype for this function is:\r
1659  *\r
1660  * void prvIdleTask( void *pvParameters );\r
1661  *\r
1662  */\r
1663 static portTASK_FUNCTION( prvIdleTask, pvParameters )\r
1664 {\r
1665         /* Stop warnings. */\r
1666         ( void ) pvParameters;\r
1667 \r
1668         for( ;; )\r
1669         {\r
1670                 /* See if any tasks have been deleted. */\r
1671                 prvCheckTasksWaitingTermination();\r
1672 \r
1673                 #if ( configUSE_PREEMPTION == 0 )\r
1674                 {\r
1675                         /* If we are not using preemption we keep forcing a task switch to\r
1676                         see if any other task has become available.  If we are using\r
1677                         preemption we don't need to do this as any task becoming available\r
1678                         will automatically get the processor anyway. */\r
1679                         taskYIELD();    \r
1680                 }\r
1681                 #endif\r
1682 \r
1683                 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )\r
1684                 {\r
1685                         /* When using preemption tasks of equal priority will be\r
1686                         timesliced.  If a task that is sharing the idle priority is ready\r
1687                         to run then the idle task should yield before the end of the\r
1688                         timeslice.\r
1689                         \r
1690                         A critical region is not required here as we are just reading from\r
1691                         the list, and an occasional incorrect value will not matter.  If\r
1692                         the ready list at the idle priority contains more than one task\r
1693                         then a task other than the idle task is ready to execute. */\r
1694                         if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )\r
1695                         {\r
1696                                 taskYIELD();\r
1697                         }\r
1698                 }\r
1699                 #endif\r
1700 \r
1701                 #if ( configUSE_IDLE_HOOK == 1 )\r
1702                 {\r
1703                         extern void vApplicationIdleHook( void );\r
1704 \r
1705                         /* Call the user defined function from within the idle task.  This\r
1706                         allows the application designer to add background functionality\r
1707                         without the overhead of a separate task.\r
1708                         NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,\r
1709                         CALL A FUNCTION THAT MIGHT BLOCK. */\r
1710                         vApplicationIdleHook();\r
1711                 }\r
1712                 #endif\r
1713         }\r
1714 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */\r
1715 \r
1716 \r
1717 \r
1718 \r
1719 \r
1720 \r
1721 \r
1722 /*-----------------------------------------------------------\r
1723  * File private functions documented at the top of the file.\r
1724  *----------------------------------------------------------*/\r
1725 \r
1726 \r
1727 \r
1728 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )\r
1729 {\r
1730         /* Store the function name in the TCB. */\r
1731         strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );\r
1732         pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';\r
1733 \r
1734         /* This is used as an array index so must ensure it's not too large. */\r
1735         if( uxPriority >= configMAX_PRIORITIES )\r
1736         {\r
1737                 uxPriority = configMAX_PRIORITIES - 1;\r
1738         }\r
1739 \r
1740         pxTCB->uxPriority = uxPriority;\r
1741         #if ( configUSE_MUTEXES == 1 )\r
1742         {\r
1743                 pxTCB->uxBasePriority = uxPriority;\r
1744         }\r
1745         #endif\r
1746 \r
1747         vListInitialiseItem( &( pxTCB->xGenericListItem ) );\r
1748         vListInitialiseItem( &( pxTCB->xEventListItem ) );\r
1749 \r
1750         /* Set the pxTCB as a link back from the xListItem.  This is so we can get\r
1751         back to the containing TCB from a generic item in a list. */\r
1752         listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );\r
1753 \r
1754         /* Event lists are always in priority order. */\r
1755         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );\r
1756         listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );\r
1757 \r
1758         #if ( portCRITICAL_NESTING_IN_TCB == 1 )\r
1759         {\r
1760                 pxTCB->uxCriticalNesting = ( unsigned portBASE_TYPE ) 0;\r
1761         }\r
1762         #endif\r
1763 \r
1764         #if ( configUSE_APPLICATION_TASK_TAG == 1 )\r
1765         {\r
1766                 pxTCB->pxTaskTag = NULL;\r
1767         }\r
1768         #endif  \r
1769 }\r
1770 /*-----------------------------------------------------------*/\r
1771 \r
1772 static void prvInitialiseTaskLists( void )\r
1773 {\r
1774 unsigned portBASE_TYPE uxPriority;\r
1775 \r
1776         for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )\r
1777         {\r
1778                 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );\r
1779         }\r
1780 \r
1781         vListInitialise( ( xList * ) &xDelayedTaskList1 );\r
1782         vListInitialise( ( xList * ) &xDelayedTaskList2 );\r
1783         vListInitialise( ( xList * ) &xPendingReadyList );\r
1784 \r
1785         #if ( INCLUDE_vTaskDelete == 1 )\r
1786         {\r
1787                 vListInitialise( ( xList * ) &xTasksWaitingTermination );\r
1788         }\r
1789         #endif\r
1790 \r
1791         #if ( INCLUDE_vTaskSuspend == 1 )\r
1792         {\r
1793                 vListInitialise( ( xList * ) &xSuspendedTaskList );\r
1794         }\r
1795         #endif\r
1796 \r
1797         /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList\r
1798         using list2. */\r
1799         pxDelayedTaskList = &xDelayedTaskList1;\r
1800         pxOverflowDelayedTaskList = &xDelayedTaskList2;\r
1801 }\r
1802 /*-----------------------------------------------------------*/\r
1803 \r
1804 static void prvCheckTasksWaitingTermination( void )\r
1805 {                                                       \r
1806         #if ( INCLUDE_vTaskDelete == 1 )\r
1807         {                               \r
1808                 portBASE_TYPE xListIsEmpty;\r
1809 \r
1810                 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called\r
1811                 too often in the idle task. */\r
1812                 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )\r
1813                 {\r
1814                         vTaskSuspendAll();\r
1815                                 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );                          \r
1816                         xTaskResumeAll();\r
1817 \r
1818                         if( !xListIsEmpty )\r
1819                         {\r
1820                                 tskTCB *pxTCB;\r
1821 \r
1822                                 portENTER_CRITICAL();\r
1823                                 {                       \r
1824                                         pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );\r
1825                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1826                                         --uxCurrentNumberOfTasks;\r
1827                                         --uxTasksDeleted;\r
1828                                 }\r
1829                                 portEXIT_CRITICAL();\r
1830 \r
1831                                 prvDeleteTCB( pxTCB );\r
1832                         }\r
1833                 }\r
1834         }\r
1835         #endif\r
1836 }\r
1837 /*-----------------------------------------------------------*/\r
1838 \r
1839 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )\r
1840 {\r
1841 tskTCB *pxNewTCB;\r
1842 \r
1843         /* Allocate space for the TCB.  Where the memory comes from depends on\r
1844         the implementation of the port malloc function. */\r
1845         pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );\r
1846 \r
1847         if( pxNewTCB != NULL )\r
1848         {\r
1849                 /* Allocate space for the stack used by the task being created.\r
1850                 The base of the stack memory stored in the TCB so the task can\r
1851                 be deleted later if required. */\r
1852                 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );\r
1853 \r
1854                 if( pxNewTCB->pxStack == NULL )\r
1855                 {\r
1856                         /* Could not allocate the stack.  Delete the allocated TCB. */\r
1857                         vPortFree( pxNewTCB );                  \r
1858                         pxNewTCB = NULL;                        \r
1859                 }               \r
1860                 else\r
1861                 {\r
1862                         /* Just to help debugging. */\r
1863                         memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );\r
1864                 }\r
1865         }\r
1866 \r
1867         return pxNewTCB;\r
1868 }\r
1869 /*-----------------------------------------------------------*/\r
1870 \r
1871 #if ( configUSE_TRACE_FACILITY == 1 )\r
1872 \r
1873         static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )\r
1874         {\r
1875         volatile tskTCB *pxNextTCB, *pxFirstTCB;\r
1876         static portCHAR pcStatusString[ 50 ];\r
1877         unsigned portSHORT usStackRemaining;\r
1878 \r
1879                 /* Write the details of all the TCB's in pxList into the buffer. */\r
1880                 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );\r
1881                 do\r
1882                 {\r
1883                         listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );\r
1884                         usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );\r
1885                         sprintf( pcStatusString, ( portCHAR * ) "%s\t\t%c\t%u\t%u\t%u\r\n", pxNextTCB->pcTaskName, cStatus, ( unsigned int ) pxNextTCB->uxPriority, usStackRemaining, ( unsigned int ) pxNextTCB->uxTCBNumber );\r
1886                         strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );\r
1887 \r
1888                 } while( pxNextTCB != pxFirstTCB );\r
1889         }\r
1890 \r
1891 #endif\r
1892 /*-----------------------------------------------------------*/\r
1893 \r
1894 #if ( ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) )\r
1895 \r
1896         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte )\r
1897         {\r
1898         register unsigned portSHORT usCount = 0;\r
1899 \r
1900                 while( *pucStackByte == tskSTACK_FILL_BYTE )\r
1901                 {\r
1902                         pucStackByte -= portSTACK_GROWTH;\r
1903                         usCount++;\r
1904                 }\r
1905 \r
1906                 usCount /= sizeof( portSTACK_TYPE );\r
1907 \r
1908                 return usCount;\r
1909         }\r
1910 \r
1911 #endif\r
1912 /*-----------------------------------------------------------*/\r
1913 \r
1914 #if ( INCLUDE_uxTaskGetStackHighWaterMark == 1 )\r
1915 \r
1916         unsigned portBASE_TYPE uxTaskGetStackHighWaterMark( xTaskHandle xTask )\r
1917         {\r
1918         tskTCB *pxTCB;\r
1919 \r
1920                 pxTCB = prvGetTCBFromHandle( xTask );\r
1921                 return usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxTCB->pxStack );\r
1922         }\r
1923 \r
1924 #endif\r
1925 /*-----------------------------------------------------------*/\r
1926 \r
1927 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
1928 \r
1929         static void prvDeleteTCB( tskTCB *pxTCB )\r
1930         {\r
1931                 /* Free up the memory allocated by the scheduler for the task.  It is up to\r
1932                 the task to free any memory allocated at the application level. */\r
1933                 vPortFree( pxTCB->pxStack );\r
1934                 vPortFree( pxTCB );\r
1935         }\r
1936 \r
1937 #endif\r
1938 \r
1939 \r
1940 /*-----------------------------------------------------------*/\r
1941 \r
1942 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )\r
1943 \r
1944         xTaskHandle xTaskGetCurrentTaskHandle( void )\r
1945         {\r
1946         xTaskHandle xReturn;\r
1947 \r
1948                 portENTER_CRITICAL();\r
1949                 {\r
1950                         xReturn = ( xTaskHandle ) pxCurrentTCB;\r
1951                 }\r
1952                 portEXIT_CRITICAL();\r
1953 \r
1954                 return xReturn;\r
1955         }\r
1956 \r
1957 #endif\r
1958 \r
1959 /*-----------------------------------------------------------*/\r
1960 \r
1961 #if ( INCLUDE_xTaskGetSchedulerState == 1 )\r
1962 \r
1963         portBASE_TYPE xTaskGetSchedulerState( void )\r
1964         {\r
1965         portBASE_TYPE xReturn;\r
1966         \r
1967                 if( xSchedulerRunning == pdFALSE )\r
1968                 {\r
1969                         xReturn = taskSCHEDULER_NOT_STARTED;\r
1970                 }\r
1971                 else\r
1972                 {\r
1973                         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1974                         {\r
1975                                 xReturn = taskSCHEDULER_RUNNING;\r
1976                         }\r
1977                         else\r
1978                         {\r
1979                                 xReturn = taskSCHEDULER_SUSPENDED;\r
1980                         }\r
1981                 }\r
1982                 \r
1983                 return xReturn;\r
1984         }\r
1985 \r
1986 #endif\r
1987 /*-----------------------------------------------------------*/\r
1988 \r
1989 #if ( configUSE_MUTEXES == 1 )\r
1990         \r
1991         void vTaskPriorityInherit( xTaskHandle * const pxMutexHolder )\r
1992         {\r
1993         tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;\r
1994 \r
1995                 if( pxTCB->uxPriority < pxCurrentTCB->uxPriority )\r
1996                 {\r
1997                         /* Adjust the mutex holder state to account for its new priority. */\r
1998                         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxCurrentTCB->uxPriority );\r
1999 \r
2000                         /* If the task being modified is in the ready state it will need to\r
2001                         be moved in to a new list. */\r
2002                         if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
2003                         {\r
2004                                 vListRemove( &( pxTCB->xGenericListItem ) );\r
2005 \r
2006                                 /* Inherit the priority before being moved into the new list. */\r
2007                                 pxTCB->uxPriority = pxCurrentTCB->uxPriority;\r
2008                                 prvAddTaskToReadyQueue( pxTCB );\r
2009                         }\r
2010                         else\r
2011                         {\r
2012                                 /* Just inherit the priority. */\r
2013                                 pxTCB->uxPriority = pxCurrentTCB->uxPriority;\r
2014                         }\r
2015                 }\r
2016         }\r
2017 \r
2018 #endif\r
2019 /*-----------------------------------------------------------*/\r
2020 \r
2021 #if ( configUSE_MUTEXES == 1 )  \r
2022 \r
2023         void vTaskPriorityDisinherit( xTaskHandle * const pxMutexHolder )\r
2024         {\r
2025         tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;\r
2026 \r
2027                 if( pxMutexHolder != NULL )\r
2028                 {\r
2029                         if( pxTCB->uxPriority != pxTCB->uxBasePriority )\r
2030                         {\r
2031                                 /* We must be the running task to be able to give the mutex back.\r
2032                                 Remove ourselves from the ready list we currently appear in. */\r
2033                                 vListRemove( &( pxTCB->xGenericListItem ) );\r
2034 \r
2035                                 /* Disinherit the priority before adding ourselves into the new\r
2036                                 ready list. */\r
2037                                 pxTCB->uxPriority = pxTCB->uxBasePriority;\r
2038                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxTCB->uxPriority );\r
2039                                 prvAddTaskToReadyQueue( pxTCB );\r
2040                         }\r
2041                 }\r
2042         }\r
2043 \r
2044 #endif\r
2045 /*-----------------------------------------------------------*/\r
2046 \r
2047 #if ( portCRITICAL_NESTING_IN_TCB == 1 )\r
2048 \r
2049         void vTaskEnterCritical( void )\r
2050         {\r
2051                 portDISABLE_INTERRUPTS();\r
2052 \r
2053                 if( xSchedulerRunning != pdFALSE )\r
2054                 {\r
2055                         pxCurrentTCB->uxCriticalNesting++;\r
2056                 }\r
2057         }\r
2058 \r
2059 #endif\r
2060 /*-----------------------------------------------------------*/\r
2061 \r
2062 #if ( portCRITICAL_NESTING_IN_TCB == 1 )\r
2063 \r
2064 void vTaskExitCritical( void )\r
2065 {\r
2066         if( xSchedulerRunning != pdFALSE )\r
2067         {\r
2068                 if( pxCurrentTCB->uxCriticalNesting > 0 )\r
2069                 {\r
2070                         pxCurrentTCB->uxCriticalNesting--;\r
2071 \r
2072                         if( pxCurrentTCB->uxCriticalNesting == 0 )\r
2073                         {\r
2074                                 portENABLE_INTERRUPTS();\r
2075                         }\r
2076                 }\r
2077         }\r
2078 }\r
2079 \r
2080 #endif\r
2081 /*-----------------------------------------------------------*/\r
2082 \r
2083 \r
2084         \r
2085 \r