git.sur5r.net Git - freertos/blob - Source/tasks.c

   1 /*\r
   2         FreeRTOS.org V4.7.1 - 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         Please ensure to read the configuration and relevant port sections of the \r
  29         online documentation.\r
  30 \r
  31         +++ http://www.FreeRTOS.org +++\r
  32         Documentation, latest information, license and contact details.  \r
  33 \r
  34         +++ http://www.SafeRTOS.com +++\r
  35         A version that is certified for use in safety critical systems.\r
  36 \r
  37         +++ http://www.OpenRTOS.com +++\r
  38         Commercial support, development, porting, licensing and training services.\r
  39 \r
  40         ***************************************************************************\r
  41 */\r
  42 \r
  43 /*\r
  44 Changes from V1.00:\r
  45         \r
  46         + Call to portRESTORE_CONTEXT has been removed.  The first context\r
  47           switch is now performed within sPortStartScheduler().\r
  48 \r
  49 Changes from V1.01:\r
  50 \r
  51         + More use of 8bit data types.\r
  52         + Function name prefixes changed where the data type returned has changed.\r
  53         + configUSE_TRACE_FACILITY is no longer defined by default.\r
  54 \r
  55 Changes from V1.2.0\r
  56 \r
  57         + Introduced ucTopReadyPriority.  This tracks the highest priority ready\r
  58           queue that contains a valid TCB and thus makes the context switch\r
  59           slightly faster.\r
  60 \r
  61         + prvAddTaskToReadyQueue() has been made a macro.\r
  62 \r
  63 Changes from V1.2.6\r
  64 \r
  65         + Added conditional compilation directives.\r
  66         + Extended API.\r
  67         + Rearranged function order.\r
  68         + Creating a task now causes a context switch if the task being created\r
  69           has a higher priority than the calling task - assuming the kernel is\r
  70           running.\r
  71         + vTaskDelete() now only causes a context switch if the calling task is\r
  72           the task being deleted.\r
  73 \r
  74 Changes from V2.0.0\r
  75 \r
  76         + Allow the type of the tick count to be 16 or 32 bits.\r
  77         + Introduce xPendingReadyList feature to allow the time interrupts have to\r
  78           be disabled to be minimised.\r
  79         + Remove the #if( INCLUDE_vTaskSuspendAll ) statements.  vTaskSuspendAll()\r
  80           is now always included as it is used by the scheduler itself.\r
  81 \r
  82 Changes from V2.1.0\r
  83 \r
  84         + Bug fix - pxCurrentTCB is now initialised before the call to\r
  85           prvInitializeTaskLists().  Previously pxCurrentTCB could be accessed\r
  86           while null.\r
  87 \r
  88 Changed from V2.1.1\r
  89 \r
  90         + Change to where lStackSize is declared within sTaskCreate() to prevent\r
  91           compiler warnings with 8051 port.\r
  92 \r
  93 Changes from V2.2.0\r
  94 \r
  95         + Explicit use of 'signed' qualifier on portCHAR types added.\r
  96         + Changed odd calculation of initial pxTopOfStack value when\r
  97           portSTACK_GROWTH < 0.\r
  98         + Removed pcVersionNumber definition.\r
  99 \r
 100 Changes from V2.5.3\r
 101 \r
 102         + cTaskResumeAll() modified to ensure it can be called prior to the task\r
 103           lists being initialised.\r
 104 \r
 105 Changes from V2.5.5\r
 106 \r
 107         + Added API function vTaskDelayUntil().\r
 108         + Added INCLUDE_vTaskDelay conditional compilation.\r
 109 \r
 110 Changes from V2.6.0\r
 111 \r
 112         + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it\r
 113           can be used on ARM architectures.\r
 114         + tskMAX_TASK_NAME_LEN definition replaced with the port specific\r
 115           configMAX_TASK_NAME_LEN definition.\r
 116         + Removed the call to strcpy when copying across the task name into the\r
 117           TCB.\r
 118         + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called\r
 119           too often in the idle task.\r
 120 \r
 121 Changes between V3.0.0 and V2.6.1\r
 122 \r
 123         + When resuming the scheduler a yield is performed if either a tick has\r
 124           been missed, or a task is moved from the pending ready list into a ready\r
 125           list.  Previously a yield was not performed on this second condition.\r
 126         + Introduced the type portBASE_TYPE.  This necessitates several API\r
 127           changes.\r
 128         + Removed the sUsingPreemption variable.  The constant defined in\r
 129           portmacro.h is now used directly.\r
 130         + The idle task can now include an optional hook function - and no longer\r
 131           completes its time slice if other tasks with equal priority to it are\r
 132           ready to run.\r
 133         + See the FreeRTOS.org documentation for more information on V2.x.x to\r
 134           V3.x.x modifications.\r
 135 \r
 136 Changes from V3.1.1\r
 137 \r
 138         + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to\r
 139           be called while the scheduler is suspended.\r
 140         + Corrected the task ordering within event lists.\r
 141 \r
 142 Changes from V3.2.0\r
 143 \r
 144         + Added function xTaskGetCurrentTaskHandle().\r
 145 \r
 146 Changes from V3.2.4\r
 147 \r
 148         + Changed the volatile declarations on some variables to reflect the \r
 149           changes to the list definitions.\r
 150         + Changed the order of the TCB definition so there is commonality between\r
 151           the task control block and a co-routine control block.\r
 152         + Allow the scheduler to be started even if no tasks other than the idle\r
 153           task has been created.  This allows co-routines to run even when no tasks\r
 154           have been created.\r
 155         + The need for a context switch is now signalled if a task woken by an \r
 156           event has a priority greater or equal to the currently running task.\r
 157           Previously this was only greater than.\r
 158 \r
 159 Changes from V4.0.0\r
 160 \r
 161         + Added the xMissedYield handling.\r
 162 \r
 163 Changes from V4.0.1\r
 164 \r
 165         + The function vTaskList() now suspends the scheduler rather than disabling\r
 166           interrupts during the creation of the task list.  \r
 167         + Allow a task to delete itself by passing in its own handle.  Previously \r
 168           this could only be done by passing in NULL.\r
 169         + The tick hook function is now called only within a tick isr.  Previously\r
 170           it was also called when the tick function was called during the scheduler\r
 171           unlocking process.\r
 172 \r
 173 Changes from V4.0.3\r
 174 \r
 175         + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary\r
 176           yields.\r
 177 \r
 178 Changed from V4.0.4\r
 179 \r
 180         + Bug fix:  The 'value' of the event list item is updated when the priority\r
 181           of a task is changed.  Previously only the priority of the TCB itself was\r
 182           changed.\r
 183         + When resuming a task a check is first made to see if the task is actually\r
 184           suspended.\r
 185         + vTaskPrioritySet() and vTaskResume() no longer use the event list item.\r
 186           This has not been necessary since V4.0.1 when the xMissedYield handling\r
 187           was added.\r
 188         + Implement xTaskResumeFromISR().\r
 189 \r
 190 Changes from V4.0.5\r
 191 \r
 192         + Added utility functions and xOverflowCount variable to facilitate the\r
 193           queue.c changes.\r
 194 \r
 195 Changes from V4.1.2\r
 196         \r
 197         + Tasks that block on events with a timeout of portMAX_DELAY are now\r
 198           blocked indefinitely if configINCLUDE_vTaskSuspend is defined. \r
 199           Previously portMAX_DELAY was just the longest block time possible.\r
 200 \r
 201 Changes from V4.1.3\r
 202 \r
 203         + Very small change made to xTaskCheckForTimeout() as a result of the \r
 204         SafeRTOS testing.  This corrects the case where the function can return an\r
 205         invalid value - but only in an extremely unlikely scenario.\r
 206 \r
 207 Changes since V4.3.1:\r
 208 \r
 209         + Added xTaskGetSchedulerState() function.\r
 210         + Added prvIsTaskSuspended() to take into account the Occurrence of\r
 211           vTaskResume() or vTaskResumeFromISR() being called passing in the\r
 212           handle of a task that appears in the Suspended list only because it\r
 213           is blocked on an event without a timeout being specified.\r
 214         + Updated xTaskCheckForTimeout() to take into account that tasks blocked\r
 215           using the Suspended list should never time out.\r
 216 */\r
 217 \r
 218 #include <stdio.h>\r
 219 #include <stdlib.h>\r
 220 #include <string.h>\r
 221 \r
 222 #include "FreeRTOS.h"\r
 223 #include "task.h"\r
 224 \r
 225 /*\r
 226  * Macro to define the amount of stack available to the idle task.\r
 227  */\r
 228 #define tskIDLE_STACK_SIZE      configMINIMAL_STACK_SIZE\r
 229 \r
 230 \r
 231 /*\r
 232  * Default a definitions for backwards compatibility with old\r
 233  * portmacro.h files.\r
 234  */\r
 235 #ifndef configMAX_TASK_NAME_LEN\r
 236         #define configMAX_TASK_NAME_LEN 16\r
 237 #endif\r
 238 \r
 239 #ifndef configIDLE_SHOULD_YIELD\r
 240         #define configIDLE_SHOULD_YIELD         1\r
 241 #endif\r
 242 \r
 243 #if configMAX_TASK_NAME_LEN < 1\r
 244         #undef configMAX_TASK_NAME_LEN\r
 245         #define configMAX_TASK_NAME_LEN 1\r
 246 #endif\r
 247 \r
 248 #ifndef INCLUDE_xTaskResumeFromISR\r
 249         #define INCLUDE_xTaskResumeFromISR 1\r
 250 #endif\r
 251 \r
 252 #ifndef INCLUDE_xTaskGetSchedulerState\r
 253         #define INCLUDE_xTaskGetSchedulerState 0\r
 254 #endif\r
 255 \r
 256 /*\r
 257  * Task control block.  A task control block (TCB) is allocated to each task,\r
 258  * and stores the context of the task.\r
 259  */\r
 260 typedef struct tskTaskControlBlock\r
 261 {\r
 262         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
 263         xListItem                               xGenericListItem;       /*< List item used to place the TCB in ready and blocked queues. */\r
 264         xListItem                               xEventListItem;         /*< List item used to place the TCB in event lists. */\r
 265         unsigned portBASE_TYPE  uxPriority;                     /*< The priority of the task where 0 is the lowest priority. */\r
 266         portSTACK_TYPE                  *pxStack;                       /*< Points to the start of the stack. */\r
 267         signed portCHAR                 pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */\r
 268 \r
 269         #if ( configUSE_TRACE_FACILITY == 1 )\r
 270                 unsigned portBASE_TYPE  uxTCBNumber;            /*< This is used for tracing the scheduler and making debugging easier only. */\r
 271         #endif  \r
 272                 \r
 273         #if ( configUSE_MUTEXES == 1 )\r
 274                 unsigned portBASE_TYPE uxBasePriority;\r
 275         #endif\r
 276                 \r
 277 } tskTCB;\r
 278 \r
 279 /*lint -e956 */\r
 280 \r
 281 tskTCB * volatile pxCurrentTCB = NULL;                                  \r
 282 \r
 283 /* Lists for ready and blocked tasks. --------------------*/\r
 284 \r
 285 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */\r
 286 static xList xDelayedTaskList1;                                                 /*< Delayed tasks. */\r
 287 static xList xDelayedTaskList2;                                                 /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */\r
 288 static xList * volatile pxDelayedTaskList;                              /*< Points to the delayed task list currently being used. */\r
 289 static xList * volatile pxOverflowDelayedTaskList;              /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */\r
 290 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
 291 \r
 292 #if ( INCLUDE_vTaskDelete == 1 )\r
 293 \r
 294         static volatile xList xTasksWaitingTermination;         /*< Tasks that have been deleted - but the their memory not yet freed. */\r
 295         static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;\r
 296 \r
 297 #endif\r
 298 \r
 299 #if ( INCLUDE_vTaskSuspend == 1 )\r
 300 \r
 301         static xList xSuspendedTaskList;                                        /*< Tasks that are currently suspended. */\r
 302 \r
 303 #endif\r
 304 \r
 305 /* File private variables. --------------------------------*/\r
 306 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks   = ( unsigned portBASE_TYPE ) 0;\r
 307 static volatile portTickType xTickCount                                                 = ( portTickType ) 0;\r
 308 static unsigned portBASE_TYPE uxTopUsedPriority                                 = tskIDLE_PRIORITY;\r
 309 static volatile unsigned portBASE_TYPE uxTopReadyPriority               = tskIDLE_PRIORITY;\r
 310 static volatile signed portBASE_TYPE xSchedulerRunning                  = pdFALSE;\r
 311 static volatile unsigned portBASE_TYPE uxSchedulerSuspended             = ( unsigned portBASE_TYPE ) pdFALSE;\r
 312 static volatile unsigned portBASE_TYPE uxMissedTicks                    = ( unsigned portBASE_TYPE ) 0;\r
 313 static volatile portBASE_TYPE xMissedYield                                              = ( portBASE_TYPE ) pdFALSE;\r
 314 static volatile portBASE_TYPE xNumOfOverflows                                   = ( portBASE_TYPE ) 0;\r
 315 /* Debugging and trace facilities private variables and macros. ------------*/\r
 316 \r
 317 /*\r
 318  * The value used to fill the stack of a task when the task is created.  This\r
 319  * is used purely for checking the high water mark for tasks.\r
 320  */\r
 321 #define tskSTACK_FILL_BYTE      ( 0xa5 )\r
 322 \r
 323 /*\r
 324  * Macros used by vListTask to indicate which state a task is in.\r
 325  */\r
 326 #define tskBLOCKED_CHAR         ( ( signed portCHAR ) 'B' )\r
 327 #define tskREADY_CHAR           ( ( signed portCHAR ) 'R' )\r
 328 #define tskDELETED_CHAR         ( ( signed portCHAR ) 'D' )\r
 329 #define tskSUSPENDED_CHAR       ( ( signed portCHAR ) 'S' )\r
 330 \r
 331 /*\r
 332  * Macros and private variables used by the trace facility.\r
 333  */\r
 334 #if ( configUSE_TRACE_FACILITY == 1 )\r
 335 \r
 336         #define tskSIZE_OF_EACH_TRACE_LINE                      ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )\r
 337         static volatile signed portCHAR * volatile pcTraceBuffer;\r
 338         static signed portCHAR *pcTraceBufferStart;\r
 339         static signed portCHAR *pcTraceBufferEnd;\r
 340         static signed portBASE_TYPE xTracing = pdFALSE;\r
 341 \r
 342 #endif\r
 343 \r
 344 /*\r
 345  * Macro that writes a trace of scheduler activity to a buffer.  This trace\r
 346  * shows which task is running when and is very useful as a debugging tool.\r
 347  * As this macro is called each context switch it is a good idea to undefine\r
 348  * it if not using the facility.\r
 349  */\r
 350 #if ( configUSE_TRACE_FACILITY == 1 )\r
 351 \r
 352         #define vWriteTraceToBuffer()                                                                                                                                   \\r
 353         {                                                                                                                                                                                               \\r
 354                 if( xTracing )                                                                                                                                                          \\r
 355                 {                                                                                                                                                                                       \\r
 356                         static unsigned portBASE_TYPE uxPreviousTask = 255;                                                                             \\r
 357                                                                                                                                                                                                         \\r
 358                         if( uxPreviousTask != pxCurrentTCB->uxTCBNumber )                                                                               \\r
 359                         {                                                                                                                                                                               \\r
 360                                 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd )                         \\r
 361                                 {                                                                                                                                                                       \\r
 362                                         uxPreviousTask = pxCurrentTCB->uxTCBNumber;                                                                             \\r
 363                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount;              \\r
 364                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 365                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask;  \\r
 366                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 367                                 }                                                                                                                                                                       \\r
 368                                 else                                                                                                                                                            \\r
 369                                 {                                                                                                                                                                       \\r
 370                                         xTracing = pdFALSE;                                                                                                                             \\r
 371                                 }                                                                                                                                                                       \\r
 372                         }                                                                                                                                                                               \\r
 373                 }                                                                                                                                                                                       \\r
 374         }\r
 375 \r
 376 #else\r
 377 \r
 378         #define vWriteTraceToBuffer()\r
 379 \r
 380 #endif\r
 381 \r
 382 \r
 383 /*\r
 384  * Place the task represented by pxTCB into the appropriate ready queue for\r
 385  * the task.  It is inserted at the end of the list.  One quirk of this is\r
 386  * that if the task being inserted is at the same priority as the currently\r
 387  * executing task, then it will only be rescheduled after the currently\r
 388  * executing task has been rescheduled.\r
 389  */\r
 390 #define prvAddTaskToReadyQueue( pxTCB )                                                                                                                                                 \\r
 391 {                                                                                                                                                                                                                               \\r
 392         if( pxTCB->uxPriority > uxTopReadyPriority )                                                                                                                            \\r
 393         {                                                                                                                                                                                                                       \\r
 394                 uxTopReadyPriority = pxTCB->uxPriority;                                                                                                                                 \\r
 395         }                                                                                                                                                                                                                       \\r
 396         vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) );        \\r
 397 }               \r
 398 \r
 399 /*\r
 400  * Macro that looks at the list of tasks that are currently delayed to see if\r
 401  * any require waking.\r
 402  *\r
 403  * Tasks are stored in the queue in the order of their wake time - meaning\r
 404  * once one tasks has been found whose timer has not expired we need not look\r
 405  * any further down the list.\r
 406  */\r
 407 #define prvCheckDelayedTasks()                                                                                                                                                                          \\r
 408 {                                                                                                                                                                                                                                       \\r
 409 register tskTCB *pxTCB;                                                                                                                                                                                         \\r
 410                                                                                                                                                                                                                                         \\r
 411         while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL )                                              \\r
 412         {                                                                                                                                                                                                                               \\r
 413                 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) )                                                                      \\r
 414                 {                                                                                                                                                                                                                       \\r
 415                         break;                                                                                                                                                                                                  \\r
 416                 }                                                                                                                                                                                                                       \\r
 417                 vListRemove( &( pxTCB->xGenericListItem ) );                                                                                                                            \\r
 418                 /* Is the task waiting on an event also? */                                                                                                                                     \\r
 419                 if( pxTCB->xEventListItem.pvContainer )                                                                                                                                         \\r
 420                 {                                                                                                                                                                                                                       \\r
 421                         vListRemove( &( pxTCB->xEventListItem ) );                                                                                                                              \\r
 422                 }                                                                                                                                                                                                                       \\r
 423                 prvAddTaskToReadyQueue( pxTCB );                                                                                                                \\r
 424         }                                                                                                                                                                                                                               \\r
 425 }                                                                                                                                                                                       \r
 426 \r
 427 /*\r
 428  * Several functions take an xTaskHandle parameter that can optionally be NULL,\r
 429  * where NULL is used to indicate that the handle of the currently executing\r
 430  * task should be used in place of the parameter.  This macro simply checks to\r
 431  * see if the parameter is NULL and returns a pointer to the appropriate TCB.\r
 432  */\r
 433 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )\r
 434 \r
 435 \r
 436 /* File private functions. --------------------------------*/\r
 437 \r
 438 /*\r
 439  * Utility to ready a TCB for a given task.  Mainly just copies the parameters\r
 440  * into the TCB structure.\r
 441  */\r
 442 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );\r
 443 \r
 444 /*\r
 445  * Utility to ready all the lists used by the scheduler.  This is called\r
 446  * automatically upon the creation of the first task.\r
 447  */\r
 448 static void prvInitialiseTaskLists( void );\r
 449 \r
 450 /*\r
 451  * The idle task, which as all tasks is implemented as a never ending loop.\r
 452  * The idle task is automatically created and added to the ready lists upon\r
 453  * creation of the first user task.\r
 454  *\r
 455  * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific\r
 456  * language extensions.  The equivalent prototype for this function is:\r
 457  *\r
 458  * void prvIdleTask( void *pvParameters );\r
 459  *\r
 460  */\r
 461 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );\r
 462 \r
 463 /*\r
 464  * Utility to free all memory allocated by the scheduler to hold a TCB,\r
 465  * including the stack pointed to by the TCB.\r
 466  *\r
 467  * This does not free memory allocated by the task itself (i.e. memory\r
 468  * allocated by calls to pvPortMalloc from within the tasks application code).\r
 469  */\r
 470 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
 471         static void prvDeleteTCB( tskTCB *pxTCB );\r
 472 #endif\r
 473 \r
 474 /*\r
 475  * Used only by the idle task.  This checks to see if anything has been placed\r
 476  * in the list of tasks waiting to be deleted.  If so the task is cleaned up\r
 477  * and its TCB deleted.\r
 478  */\r
 479 static void prvCheckTasksWaitingTermination( void );\r
 480 \r
 481 /*\r
 482  * Allocates memory from the heap for a TCB and associated stack.  Checks the\r
 483  * allocation was successful.\r
 484  */\r
 485 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );\r
 486 \r
 487 /*\r
 488  * Called from vTaskList.  vListTasks details all the tasks currently under\r
 489  * control of the scheduler.  The tasks may be in one of a number of lists.\r
 490  * prvListTaskWithinSingleList accepts a list and details the tasks from\r
 491  * within just that list.\r
 492  *\r
 493  * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM\r
 494  * NORMAL APPLICATION CODE.\r
 495  */\r
 496 #if ( configUSE_TRACE_FACILITY == 1 )\r
 497 \r
 498         static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );\r
 499 \r
 500 #endif\r
 501 \r
 502 /*\r
 503  * When a task is created, the stack of the task is filled with a known value.\r
 504  * This function determines the 'high water mark' of the task stack by\r
 505  * determining how much of the stack remains at the original preset value.\r
 506  */\r
 507 #if ( configUSE_TRACE_FACILITY == 1 )\r
 508 \r
 509         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte );\r
 510 \r
 511 #endif\r
 512 \r
 513 /*\r
 514  * Checks that a task being resumed (unsuspended) is actually in the Suspended\r
 515  * state.\r
 516  */\r
 517 #if ( INCLUDE_vTaskSuspend == 1 )\r
 518 \r
 519         static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB );  \r
 520 \r
 521 #endif\r
 522 \r
 523 /*lint +e956 */\r
 524 \r
 525 \r
 526 \r
 527 \r
 528 \r
 529 /*-----------------------------------------------------------\r
 530  * TASK CREATION API documented in task.h\r
 531  *----------------------------------------------------------*/\r
 532 \r
 533 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )\r
 534 {\r
 535 signed portBASE_TYPE xReturn;\r
 536 tskTCB * pxNewTCB;\r
 537 #if ( configUSE_TRACE_FACILITY == 1 )\r
 538         static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */\r
 539 #endif\r
 540 \r
 541         /* Allocate the memory required by the TCB and stack for the new task.\r
 542         checking that the allocation was successful. */\r
 543         pxNewTCB = prvAllocateTCBAndStack( usStackDepth );\r
 544 \r
 545         if( pxNewTCB != NULL )\r
 546         {               \r
 547                 portSTACK_TYPE *pxTopOfStack;\r
 548 \r
 549                 /* Setup the newly allocated TCB with the initial state of the task. */\r
 550                 prvInitialiseTCBVariables( pxNewTCB, pcName, uxPriority );\r
 551 \r
 552                 /* Calculate the top of stack address.  This depends on whether the\r
 553                 stack grows from high memory to low (as per the 80x86) or visa versa.\r
 554                 portSTACK_GROWTH is used to make the result positive or negative as\r
 555                 required by the port. */\r
 556                 #if portSTACK_GROWTH < 0\r
 557                 {\r
 558                         pxTopOfStack = pxNewTCB->pxStack + ( usStackDepth - 1 );\r
 559                 }\r
 560                 #else\r
 561                 {\r
 562                         pxTopOfStack = pxNewTCB->pxStack;       \r
 563                 }\r
 564                 #endif\r
 565 \r
 566                 /* Initialize the TCB stack to look as if the task was already running,\r
 567                 but had been interrupted by the scheduler.  The return address is set\r
 568                 to the start of the task function. Once the stack has been initialised\r
 569                 the     top of stack variable is updated. */\r
 570                 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );\r
 571 \r
 572                 /* We are going to manipulate the task queues to add this task to a\r
 573                 ready list, so must make sure no interrupts occur. */\r
 574                 portENTER_CRITICAL();\r
 575                 {\r
 576                         uxCurrentNumberOfTasks++;\r
 577                         if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )\r
 578                         {\r
 579                                 /* As this is the first task it must also be the current task. */\r
 580                                 pxCurrentTCB =  pxNewTCB;\r
 581 \r
 582                                 /* This is the first task to be created so do the preliminary\r
 583                                 initialisation required.  We will not recover if this call\r
 584                                 fails, but we will report the failure. */\r
 585                                 prvInitialiseTaskLists();\r
 586                         }\r
 587                         else\r
 588                         {       \r
 589                                 /* If the scheduler is not already running, make this task the\r
 590                                 current task if it is the highest priority task to be created\r
 591                                 so far. */\r
 592                                 if( xSchedulerRunning == pdFALSE )\r
 593                                 {\r
 594                                         if( pxCurrentTCB->uxPriority <= uxPriority )\r
 595                                         {\r
 596                                                 pxCurrentTCB = pxNewTCB;        \r
 597                                         }\r
 598                                 }\r
 599                         }                               \r
 600 \r
 601                         /* Remember the top priority to make context switching faster.  Use\r
 602                         the priority in pxNewTCB as this has been capped to a valid value. */\r
 603                         if( pxNewTCB->uxPriority > uxTopUsedPriority )\r
 604                         {\r
 605                                 uxTopUsedPriority = pxNewTCB->uxPriority;\r
 606                         }\r
 607 \r
 608                         #if ( configUSE_TRACE_FACILITY == 1 )\r
 609                         {\r
 610                                 /* Add a counter into the TCB for tracing only. */\r
 611                                 pxNewTCB->uxTCBNumber = uxTaskNumber;\r
 612                                 uxTaskNumber++;\r
 613                         }\r
 614                         #endif\r
 615 \r
 616                         prvAddTaskToReadyQueue( pxNewTCB );\r
 617 \r
 618                         xReturn = pdPASS;\r
 619                 }\r
 620                 portEXIT_CRITICAL();\r
 621         }\r
 622         else\r
 623         {\r
 624                 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;\r
 625         }\r
 626 \r
 627         if( xReturn == pdPASS )\r
 628         {\r
 629                 if( ( void * ) pxCreatedTask != NULL )\r
 630                 {\r
 631                         /* Pass the TCB out - in an anonymous way.  The calling function/\r
 632                         task can use this as a handle to delete the task later if\r
 633                         required.*/\r
 634                         *pxCreatedTask = ( xTaskHandle ) pxNewTCB;\r
 635                 }\r
 636 \r
 637                 if( xSchedulerRunning != pdFALSE )\r
 638                 {\r
 639                         /* If the created task is of a higher priority than the current task\r
 640                         then it should run now. */\r
 641                         if( pxCurrentTCB->uxPriority < uxPriority )\r
 642                         {\r
 643                                 taskYIELD();\r
 644                         }\r
 645                 }\r
 646         }\r
 647 \r
 648         return xReturn;\r
 649 }\r
 650 /*-----------------------------------------------------------*/\r
 651 \r
 652 #if ( INCLUDE_vTaskDelete == 1 )\r
 653 \r
 654         void vTaskDelete( xTaskHandle pxTaskToDelete )\r
 655         {\r
 656         tskTCB *pxTCB;\r
 657 \r
 658                 taskENTER_CRITICAL();\r
 659                 {\r
 660                         /* Ensure a yield is performed if the current task is being \r
 661                         deleted. */\r
 662                         if( pxTaskToDelete == pxCurrentTCB )\r
 663                         {\r
 664                                 pxTaskToDelete = NULL;\r
 665                         }\r
 666 \r
 667                         /* If null is passed in here then we are deleting ourselves. */\r
 668                         pxTCB = prvGetTCBFromHandle( pxTaskToDelete );\r
 669 \r
 670                         /* Remove task from the ready list and place in the     termination list.\r
 671                         This will stop the task from be scheduled.  The idle task will check\r
 672                         the termination list and free up any memory allocated by the\r
 673                         scheduler for the TCB and stack. */\r
 674                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 675 \r
 676                         /* Is the task waiting on an event also? */                                                                                             \r
 677                         if( pxTCB->xEventListItem.pvContainer )\r
 678                         {\r
 679                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 680                         }\r
 681 \r
 682                         vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );\r
 683 \r
 684                         /* Increment the ucTasksDeleted variable so the idle task knows\r
 685                         there is a task that has been deleted and that it should therefore\r
 686                         check the xTasksWaitingTermination list. */\r
 687                         ++uxTasksDeleted;\r
 688                 }\r
 689                 taskEXIT_CRITICAL();\r
 690 \r
 691                 /* Force a reschedule if we have just deleted the current task. */\r
 692                 if( xSchedulerRunning != pdFALSE ) \r
 693                 {\r
 694                         if( ( void * ) pxTaskToDelete == NULL )\r
 695                         {\r
 696                                 taskYIELD();\r
 697                         }\r
 698                 }\r
 699         }\r
 700 \r
 701 #endif\r
 702 \r
 703 \r
 704 \r
 705 \r
 706 \r
 707 \r
 708 /*-----------------------------------------------------------\r
 709  * TASK CONTROL API documented in task.h\r
 710  *----------------------------------------------------------*/\r
 711 \r
 712 #if ( INCLUDE_vTaskDelayUntil == 1 )\r
 713 \r
 714         void vTaskDelayUntil( portTickType * const pxPreviousWakeTime, portTickType xTimeIncrement )\r
 715         {\r
 716         portTickType xTimeToWake;\r
 717         portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;\r
 718 \r
 719                 vTaskSuspendAll();\r
 720                 {\r
 721                         /* Generate the tick time at which the task wants to wake. */\r
 722                         xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;\r
 723 \r
 724                         if( xTickCount < *pxPreviousWakeTime )\r
 725                         {\r
 726                                 /* The tick count has overflowed since this function was\r
 727                                 lasted called.  In this case the only time we should ever\r
 728                                 actually delay is if the wake time has also     overflowed,\r
 729                                 and the wake time is greater than the tick time.  When this\r
 730                                 is the case it is as if neither time had overflowed. */\r
 731                                 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )\r
 732                                 {\r
 733                                         xShouldDelay = pdTRUE;\r
 734                                 }\r
 735                         }\r
 736                         else\r
 737                         {\r
 738                                 /* The tick time has not overflowed.  In this case we will\r
 739                                 delay if either the wake time has overflowed, and/or the\r
 740                                 tick time is less than the wake time. */\r
 741                                 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )\r
 742                                 {\r
 743                                         xShouldDelay = pdTRUE;\r
 744                                 }\r
 745                         }\r
 746 \r
 747                         /* Update the wake time ready for the next call. */\r
 748                         *pxPreviousWakeTime = xTimeToWake;\r
 749 \r
 750                         if( xShouldDelay )\r
 751                         {\r
 752                                 /* We must remove ourselves from the ready list before adding\r
 753                                 ourselves to the blocked list as the same list item is used for\r
 754                                 both lists. */\r
 755                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 756 \r
 757                                 /* The list item will be inserted in wake time order. */\r
 758                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 759 \r
 760                                 if( xTimeToWake < xTickCount )\r
 761                                 {\r
 762                                         /* Wake time has overflowed.  Place this item in the\r
 763                                         overflow list. */\r
 764                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 765                                 }\r
 766                                 else\r
 767                                 {\r
 768                                         /* The wake time has not overflowed, so we can use the\r
 769                                         current block list. */\r
 770                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 771                                 }\r
 772                         }\r
 773                 }\r
 774                 xAlreadyYielded = xTaskResumeAll();\r
 775 \r
 776                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 777                 have put ourselves to sleep. */\r
 778                 if( !xAlreadyYielded )\r
 779                 {\r
 780                         taskYIELD();\r
 781                 }\r
 782         }       \r
 783         \r
 784 #endif\r
 785 /*-----------------------------------------------------------*/\r
 786 \r
 787 #if ( INCLUDE_vTaskDelay == 1 )\r
 788 \r
 789         void vTaskDelay( portTickType xTicksToDelay )\r
 790         {\r
 791         portTickType xTimeToWake;\r
 792         signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
 793 \r
 794                 /* A delay time of zero just forces a reschedule. */\r
 795                 if( xTicksToDelay > ( portTickType ) 0 )\r
 796                 {\r
 797                         vTaskSuspendAll();\r
 798                         {\r
 799                                 /* A task that is removed from the event list while the\r
 800                                 scheduler is suspended will not get placed in the ready\r
 801                                 list or removed from the blocked list until the scheduler\r
 802                                 is resumed.\r
 803                                 \r
 804                                 This task cannot be in an event list as it is the currently\r
 805                                 executing task. */\r
 806 \r
 807                                 /* Calculate the time to wake - this may overflow but this is\r
 808                                 not a problem. */\r
 809                                 xTimeToWake = xTickCount + xTicksToDelay;\r
 810 \r
 811                                 /* We must remove ourselves from the ready list before adding\r
 812                                 ourselves to the blocked list as the same list item is used for\r
 813                                 both lists. */\r
 814                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 815 \r
 816                                 /* The list item will be inserted in wake time order. */\r
 817                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 818 \r
 819                                 if( xTimeToWake < xTickCount )\r
 820                                 {\r
 821                                         /* Wake time has overflowed.  Place this item in the\r
 822                                         overflow list. */\r
 823                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 824                                 }\r
 825                                 else\r
 826                                 {\r
 827                                         /* The wake time has not overflowed, so we can use the\r
 828                                         current block list. */\r
 829                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 830                                 }\r
 831                         }\r
 832                         xAlreadyYielded = xTaskResumeAll();\r
 833                 }\r
 834                 \r
 835                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 836                 have put ourselves to sleep. */\r
 837                 if( !xAlreadyYielded )\r
 838                 {\r
 839                         taskYIELD();\r
 840                 }\r
 841         }\r
 842         \r
 843 #endif\r
 844 /*-----------------------------------------------------------*/\r
 845 \r
 846 #if ( INCLUDE_uxTaskPriorityGet == 1 )\r
 847 \r
 848         unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )\r
 849         {\r
 850         tskTCB *pxTCB;\r
 851         unsigned portBASE_TYPE uxReturn;\r
 852 \r
 853                 taskENTER_CRITICAL();\r
 854                 {\r
 855                         /* If null is passed in here then we are changing the\r
 856                         priority of the calling function. */\r
 857                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 858                         uxReturn = pxTCB->uxPriority;\r
 859                 }\r
 860                 taskEXIT_CRITICAL();\r
 861 \r
 862                 return uxReturn;\r
 863         }\r
 864 \r
 865 #endif\r
 866 /*-----------------------------------------------------------*/\r
 867 \r
 868 #if ( INCLUDE_vTaskPrioritySet == 1 )\r
 869 \r
 870         void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )\r
 871         {\r
 872         tskTCB *pxTCB;\r
 873         unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;\r
 874 \r
 875                 /* Ensure the new priority is valid. */\r
 876                 if( uxNewPriority >= configMAX_PRIORITIES )\r
 877                 {\r
 878                         uxNewPriority = configMAX_PRIORITIES - 1;\r
 879                 }\r
 880 \r
 881                 taskENTER_CRITICAL();\r
 882                 {\r
 883                         /* If null is passed in here then we are changing the\r
 884                         priority of the calling function. */\r
 885                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 886                         \r
 887                         #if ( configUSE_MUTEXES == 1 )\r
 888                         {\r
 889                                 uxCurrentPriority = pxTCB->uxBasePriority;\r
 890                         }\r
 891                         #else\r
 892                         {\r
 893                                 uxCurrentPriority = pxTCB->uxPriority;\r
 894                         }\r
 895                         #endif\r
 896 \r
 897                         if( uxCurrentPriority != uxNewPriority )\r
 898                         {\r
 899                                 /* The priority change may have readied a task of higher\r
 900                                 priority than the calling task. */\r
 901                                 if( uxNewPriority > uxCurrentPriority ) \r
 902                                 {\r
 903                                         if( pxTask != NULL )\r
 904                                         {\r
 905                                                 /* The priority of another task is being raised.  If we\r
 906                                                 were raising the priority of the currently running task\r
 907                                                 there would be no need to switch as it must have already\r
 908                                                 been the highest priority task. */\r
 909                                                 xYieldRequired = pdTRUE;\r
 910                                         }\r
 911                                 }\r
 912                                 else if( pxTask == NULL )\r
 913                                 {\r
 914                                         /* Setting our own priority down means there may now be another\r
 915                                         task of higher priority that is ready to execute. */\r
 916                                         xYieldRequired = pdTRUE;\r
 917                                 }\r
 918                         \r
 919                                 \r
 920 \r
 921                                 #if ( configUSE_MUTEXES == 1 )\r
 922                                 {\r
 923                                         /* Only change the priority being used if the task is not\r
 924                                         currently using an inherited priority. */\r
 925                                         if( pxTCB->uxBasePriority == pxTCB->uxPriority )\r
 926                                         {\r
 927                                                 pxTCB->uxPriority = uxNewPriority;\r
 928                                         }\r
 929                                         \r
 930                                         /* The base priority gets set whatever. */\r
 931                                         pxTCB->uxBasePriority = uxNewPriority;                                  \r
 932                                 }\r
 933                                 #else\r
 934                                 {\r
 935                                         pxTCB->uxPriority = uxNewPriority;\r
 936                                 }\r
 937                                 #endif\r
 938 \r
 939                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), ( configMAX_PRIORITIES - ( portTickType ) uxNewPriority ) );\r
 940 \r
 941                                 /* If the task is in the blocked or suspended list we need do\r
 942                                 nothing more than change it's priority variable. However, if\r
 943                                 the task is in a ready list it needs to be removed and placed\r
 944                                 in the queue appropriate to its new priority. */\r
 945                                 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
 946                                 {\r
 947                                         /* The task is currently in its ready list - remove before adding\r
 948                                         it to it's new ready list.  As we are in a critical section we\r
 949                                         can do this even if the scheduler is suspended. */\r
 950                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 951                                         prvAddTaskToReadyQueue( pxTCB );\r
 952                                 }                       \r
 953                                 \r
 954                                 if( xYieldRequired == pdTRUE )\r
 955                                 {\r
 956                                         taskYIELD();\r
 957                                 }                               \r
 958                         }\r
 959                 }\r
 960                 taskEXIT_CRITICAL();\r
 961         }\r
 962 \r
 963 #endif\r
 964 /*-----------------------------------------------------------*/\r
 965 \r
 966 #if ( INCLUDE_vTaskSuspend == 1 )\r
 967 \r
 968         void vTaskSuspend( xTaskHandle pxTaskToSuspend )\r
 969         {\r
 970         tskTCB *pxTCB;\r
 971 \r
 972                 taskENTER_CRITICAL();\r
 973                 {\r
 974                         /* Ensure a yield is performed if the current task is being \r
 975                         suspended. */\r
 976                         if( pxTaskToSuspend == pxCurrentTCB )\r
 977                         {\r
 978                                 pxTaskToSuspend = NULL;\r
 979                         }\r
 980 \r
 981                         /* If null is passed in here then we are suspending ourselves. */\r
 982                         pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );\r
 983 \r
 984                         /* Remove task from the ready/delayed list and place in the     suspended list. */\r
 985                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 986 \r
 987                         /* Is the task waiting on an event also? */                                                                                             \r
 988                         if( pxTCB->xEventListItem.pvContainer )\r
 989                         {\r
 990                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 991                         }\r
 992 \r
 993                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );\r
 994                 }\r
 995                 taskEXIT_CRITICAL();\r
 996 \r
 997                 /* We may have just suspended the current task. */\r
 998                 if( ( void * ) pxTaskToSuspend == NULL )\r
 999                 {\r
1000                         taskYIELD();\r
1001                 }\r
1002         }\r
1003 \r
1004 #endif\r
1005 /*-----------------------------------------------------------*/\r
1006 \r
1007 #if ( INCLUDE_vTaskSuspend == 1 )\r
1008 \r
1009         static portBASE_TYPE prvIsTaskSuspended( const tskTCB * const pxTCB )\r
1010         {\r
1011         portBASE_TYPE xReturn = pdFALSE;\r
1012 \r
1013                 /* Is the task we are attempting to resume actually in the\r
1014                 suspended list? */\r
1015                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
1016                 {\r
1017                         /* Has the task already been resumed from within an ISR? */\r
1018                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
1019                         {                       \r
1020                                 /* Is it in the suspended list because it is in the\r
1021                                 Suspended state?  It is possible to be in the suspended\r
1022                                 list because it is blocked on a task with no timeout\r
1023                                 specified. */\r
1024                                 if( listIS_CONTAINED_WITHIN( NULL, &( pxTCB->xEventListItem ) ) == pdTRUE )\r
1025                                 {\r
1026                                         xReturn = pdTRUE;\r
1027                                 }\r
1028                         }\r
1029                 }\r
1030 \r
1031                 return xReturn;\r
1032         }\r
1033 \r
1034 #endif\r
1035 /*-----------------------------------------------------------*/\r
1036 \r
1037 #if ( INCLUDE_vTaskSuspend == 1 )\r
1038 \r
1039         void vTaskResume( xTaskHandle pxTaskToResume )\r
1040         {\r
1041         tskTCB *pxTCB;\r
1042 \r
1043                 /* Remove the task from whichever list it is currently in, and place\r
1044                 it in the ready list. */\r
1045                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
1046 \r
1047                 /* The parameter cannot be NULL as it is impossible to resume the\r
1048                 currently executing task. */\r
1049                 if( pxTCB != NULL )\r
1050                 {\r
1051                         taskENTER_CRITICAL();\r
1052                         {\r
1053                                 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )\r
1054                                 {\r
1055                                         /* As we are in a critical section we can access the ready\r
1056                                         lists even if the scheduler is suspended. */\r
1057                                         vListRemove(  &( pxTCB->xGenericListItem ) );\r
1058                                         prvAddTaskToReadyQueue( pxTCB );\r
1059 \r
1060                                         /* We may have just resumed a higher priority task. */\r
1061                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1062                                         {\r
1063                                                 /* This yield may not cause the task just resumed to run, but\r
1064                                                 will leave the lists in the correct state for the next yield. */\r
1065                                                 taskYIELD();\r
1066                                         }\r
1067                                 }\r
1068                         }\r
1069                         taskEXIT_CRITICAL();\r
1070                 }\r
1071         }\r
1072 \r
1073 #endif\r
1074 \r
1075 /*-----------------------------------------------------------*/\r
1076 \r
1077 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1078 \r
1079         portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )\r
1080         {\r
1081         portBASE_TYPE xYieldRequired = pdFALSE;\r
1082         tskTCB *pxTCB;\r
1083 \r
1084                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
1085 \r
1086                 if( prvIsTaskSuspended( pxTCB ) == pdTRUE )\r
1087                 {\r
1088                         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1089                         {\r
1090                                 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );\r
1091                                 vListRemove(  &( pxTCB->xGenericListItem ) );   \r
1092                                 prvAddTaskToReadyQueue( pxTCB );\r
1093                         }\r
1094                         else\r
1095                         {\r
1096                                 /* We cannot access the delayed or ready lists, so will hold this\r
1097                                 task pending until the scheduler is resumed, at which point a\r
1098                                 yield will be performed if necessary. */\r
1099                                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );\r
1100                         }\r
1101                 }\r
1102 \r
1103                 return xYieldRequired;\r
1104         }\r
1105 \r
1106 #endif\r
1107 \r
1108 \r
1109 \r
1110 \r
1111 /*-----------------------------------------------------------\r
1112  * PUBLIC SCHEDULER CONTROL documented in task.h\r
1113  *----------------------------------------------------------*/\r
1114 \r
1115 \r
1116 void vTaskStartScheduler( void )\r
1117 {\r
1118 portBASE_TYPE xReturn;\r
1119 \r
1120         /* Add the idle task at the lowest priority. */\r
1121         xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );\r
1122 \r
1123         if( xReturn == pdPASS )\r
1124         {\r
1125                 /* Interrupts are turned off here, to ensure a tick does not occur\r
1126                 before or during the call to xPortStartScheduler().  The stacks of\r
1127                 the created tasks contain a status word with interrupts switched on\r
1128                 so interrupts will automatically get re-enabled when the first task\r
1129                 starts to run.\r
1130                 \r
1131                 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE\r
1132                 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */\r
1133                 portDISABLE_INTERRUPTS();\r
1134 \r
1135                 xSchedulerRunning = pdTRUE;\r
1136                 xTickCount = ( portTickType ) 0;\r
1137 \r
1138                 /* Setting up the timer tick is hardware specific and thus in the\r
1139                 portable interface. */\r
1140                 if( xPortStartScheduler() )\r
1141                 {\r
1142                         /* Should not reach here as if the scheduler is running the\r
1143                         function will not return. */\r
1144                 }\r
1145                 else\r
1146                 {\r
1147                         /* Should only reach here if a task calls xTaskEndScheduler(). */\r
1148                 }\r
1149         }\r
1150 }\r
1151 /*-----------------------------------------------------------*/\r
1152 \r
1153 void vTaskEndScheduler( void )\r
1154 {\r
1155         /* Stop the scheduler interrupts and call the portable scheduler end\r
1156         routine so the original ISRs can be restored if necessary.  The port\r
1157         layer must ensure interrupts enable     bit is left in the correct state. */\r
1158         portDISABLE_INTERRUPTS();\r
1159         xSchedulerRunning = pdFALSE;\r
1160         vPortEndScheduler();\r
1161 }\r
1162 /*----------------------------------------------------------*/\r
1163 \r
1164 void vTaskSuspendAll( void )\r
1165 {\r
1166         portENTER_CRITICAL();\r
1167                 ++uxSchedulerSuspended;\r
1168         portEXIT_CRITICAL();\r
1169 }\r
1170 /*----------------------------------------------------------*/\r
1171 \r
1172 signed portBASE_TYPE xTaskResumeAll( void )\r
1173 {\r
1174 register tskTCB *pxTCB;\r
1175 signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
1176 \r
1177         /* It is possible that an ISR caused a task to be removed from an event\r
1178         list while the scheduler was suspended.  If this was the case then the\r
1179         removed task will have been added to the xPendingReadyList.  Once the\r
1180         scheduler has been resumed it is safe to move all the pending ready\r
1181         tasks from this list into their appropriate ready list. */\r
1182         portENTER_CRITICAL();\r
1183         {\r
1184                 --uxSchedulerSuspended;\r
1185 \r
1186                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1187                 {                       \r
1188                         if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )\r
1189                         {\r
1190                                 portBASE_TYPE xYieldRequired = pdFALSE;\r
1191                                 \r
1192                                 /* Move any readied tasks from the pending list into the\r
1193                                 appropriate ready list. */\r
1194                                 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY(  ( ( xList * ) &xPendingReadyList ) ) ) != NULL )\r
1195                                 {\r
1196                                         vListRemove( &( pxTCB->xEventListItem ) );\r
1197                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1198                                         prvAddTaskToReadyQueue( pxTCB );\r
1199                                         \r
1200                                         /* If we have moved a task that has a priority higher than\r
1201                                         the current task then we should yield. */\r
1202                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1203                                         {\r
1204                                                 xYieldRequired = pdTRUE;\r
1205                                         }\r
1206                                 }\r
1207 \r
1208                                 /* If any ticks occurred while the scheduler was suspended then\r
1209                                 they should be processed now.  This ensures the tick count does not\r
1210                                 slip, and that any delayed tasks are resumed at the correct time. */\r
1211                                 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1212                                 {\r
1213                                         while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1214                                         {\r
1215                                                 vTaskIncrementTick();\r
1216                                                 --uxMissedTicks;\r
1217                                         }\r
1218 \r
1219                                         /* As we have processed some ticks it is appropriate to yield\r
1220                                         to ensure the highest priority task that is ready to run is\r
1221                                         the task actually running. */\r
1222                                         #if configUSE_PREEMPTION == 1\r
1223                                         {\r
1224                                                 xYieldRequired = pdTRUE;\r
1225                                         }\r
1226                                         #endif\r
1227                                 }\r
1228                                 \r
1229                                 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )\r
1230                                 {\r
1231                                         xAlreadyYielded = pdTRUE;\r
1232                                         xMissedYield = pdFALSE;\r
1233                                         taskYIELD();\r
1234                                 }\r
1235                         }\r
1236                 }\r
1237         }\r
1238         portEXIT_CRITICAL();\r
1239 \r
1240         return xAlreadyYielded;\r
1241 }\r
1242 \r
1243 \r
1244 \r
1245 \r
1246 \r
1247 \r
1248 /*-----------------------------------------------------------\r
1249  * PUBLIC TASK UTILITIES documented in task.h\r
1250  *----------------------------------------------------------*/\r
1251 \r
1252 \r
1253 \r
1254 portTickType xTaskGetTickCount( void )\r
1255 {\r
1256 portTickType xTicks;\r
1257 \r
1258         /* Critical section required if running on a 16 bit processor. */\r
1259         taskENTER_CRITICAL();\r
1260         {\r
1261                 xTicks = xTickCount;\r
1262         }\r
1263         taskEXIT_CRITICAL();\r
1264 \r
1265         return xTicks;\r
1266 }\r
1267 /*-----------------------------------------------------------*/\r
1268 \r
1269 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )\r
1270 {\r
1271 unsigned portBASE_TYPE uxNumberOfTasks;\r
1272 \r
1273         taskENTER_CRITICAL();\r
1274                 uxNumberOfTasks = uxCurrentNumberOfTasks;\r
1275         taskEXIT_CRITICAL();\r
1276 \r
1277         return uxNumberOfTasks;\r
1278 }\r
1279 /*-----------------------------------------------------------*/\r
1280 \r
1281 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1282 \r
1283         void vTaskList( signed portCHAR *pcWriteBuffer )\r
1284         {\r
1285         unsigned portBASE_TYPE uxQueue;\r
1286 \r
1287                 /* This is a VERY costly function that should be used for debug only.\r
1288                 It leaves interrupts disabled for a LONG time. */\r
1289 \r
1290         vTaskSuspendAll();\r
1291                 {\r
1292                         /* Run through all the lists that could potentially contain a TCB and\r
1293                         report the task name, state and stack high water mark. */\r
1294 \r
1295                         pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;\r
1296                         strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );\r
1297 \r
1298                         uxQueue = uxTopUsedPriority + 1;\r
1299 \r
1300                         do\r
1301                         {\r
1302                                 uxQueue--;\r
1303 \r
1304                                 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )\r
1305                                 {\r
1306                                         prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );                     \r
1307                                 }\r
1308                         }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1309 \r
1310                         if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )\r
1311                         {\r
1312                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );\r
1313                         }\r
1314 \r
1315                         if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )\r
1316                         {\r
1317                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );\r
1318                         }\r
1319 \r
1320                         if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )\r
1321                         {\r
1322                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );\r
1323                         }\r
1324 \r
1325                         if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1326                         {\r
1327                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );\r
1328                         }\r
1329                 }\r
1330         xTaskResumeAll();\r
1331         }\r
1332 \r
1333 #endif\r
1334 /*----------------------------------------------------------*/\r
1335 \r
1336 #if ( configUSE_TRACE_FACILITY == 1 )\r
1337 \r
1338         void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )\r
1339         {\r
1340                 portENTER_CRITICAL();\r
1341                 {\r
1342                         pcTraceBuffer = ( signed portCHAR * )pcBuffer;\r
1343                         pcTraceBufferStart = pcBuffer;\r
1344                         pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );\r
1345                         xTracing = pdTRUE;\r
1346                 }\r
1347                 portEXIT_CRITICAL();\r
1348         }\r
1349 \r
1350 #endif\r
1351 /*----------------------------------------------------------*/\r
1352 \r
1353 #if ( configUSE_TRACE_FACILITY == 1 )\r
1354 \r
1355         unsigned portLONG ulTaskEndTrace( void )\r
1356         {\r
1357         unsigned portLONG ulBufferLength;\r
1358 \r
1359                 portENTER_CRITICAL();\r
1360                         xTracing = pdFALSE;\r
1361                 portEXIT_CRITICAL();\r
1362 \r
1363                 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );\r
1364 \r
1365                 return ulBufferLength;\r
1366         }\r
1367 \r
1368 #endif\r
1369 \r
1370 \r
1371 \r
1372 /*-----------------------------------------------------------\r
1373  * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES\r
1374  * documented in task.h\r
1375  *----------------------------------------------------------*/\r
1376 \r
1377 \r
1378 inline void vTaskIncrementTick( void )\r
1379 {\r
1380         /* Called by the portable layer each time a tick interrupt occurs.\r
1381         Increments the tick then checks to see if the new tick value will cause any\r
1382         tasks to be unblocked. */\r
1383         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1384         {\r
1385                 ++xTickCount;\r
1386                 if( xTickCount == ( portTickType ) 0 )\r
1387                 {\r
1388                         xList *pxTemp;\r
1389 \r
1390                         /* Tick count has overflowed so we need to swap the delay lists.  \r
1391                         If there are any items in pxDelayedTaskList here then there is \r
1392                         an error! */\r
1393                         pxTemp = pxDelayedTaskList;\r
1394                         pxDelayedTaskList = pxOverflowDelayedTaskList;\r
1395                         pxOverflowDelayedTaskList = pxTemp;\r
1396             xNumOfOverflows++;\r
1397                 }\r
1398 \r
1399                 /* See if this tick has made a timeout expire. */\r
1400                 prvCheckDelayedTasks();\r
1401         }\r
1402         else\r
1403         {\r
1404                 ++uxMissedTicks;\r
1405 \r
1406                 /* The tick hook gets called at regular intervals, even if the \r
1407                 scheduler is locked. */\r
1408                 #if ( configUSE_TICK_HOOK == 1 )\r
1409                 {\r
1410                         extern void vApplicationTickHook( void );\r
1411 \r
1412                         vApplicationTickHook();\r
1413                 }\r
1414                 #endif\r
1415         }\r
1416 \r
1417         #if ( configUSE_TICK_HOOK == 1 )\r
1418         {\r
1419                 extern void vApplicationTickHook( void );\r
1420 \r
1421                 /* Guard against the tick hook being called when the missed tick\r
1422                 count is being unwound (when the scheduler is being unlocked. */\r
1423                 if( uxMissedTicks == 0 )\r
1424                 {\r
1425                         vApplicationTickHook();\r
1426                 }\r
1427         }\r
1428         #endif\r
1429 }\r
1430 /*-----------------------------------------------------------*/\r
1431 \r
1432 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1433 \r
1434         void vTaskCleanUpResources( void )\r
1435         {\r
1436         unsigned portSHORT usQueue;\r
1437         volatile tskTCB *pxTCB;\r
1438 \r
1439                 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;\r
1440 \r
1441                 /* Remove any TCB's from the ready queues. */\r
1442                 do\r
1443                 {\r
1444                         usQueue--;\r
1445 \r
1446                         while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )\r
1447                         {\r
1448                                 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );\r
1449                                 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1450 \r
1451                                 prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1452                         }\r
1453                 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1454 \r
1455                 /* Remove any TCB's from the delayed queue. */\r
1456                 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )\r
1457                 {\r
1458                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );\r
1459                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1460 \r
1461                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1462                 }\r
1463 \r
1464                 /* Remove any TCB's from the overflow delayed queue. */\r
1465                 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )\r
1466                 {\r
1467                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );\r
1468                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1469 \r
1470                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1471                 }\r
1472 \r
1473                 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1474                 {\r
1475                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );\r
1476                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1477 \r
1478                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1479                 }               \r
1480         }\r
1481 \r
1482 #endif\r
1483 /*-----------------------------------------------------------*/\r
1484 \r
1485 void vTaskSwitchContext( void )\r
1486 {\r
1487         if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )\r
1488         {\r
1489                 /* The scheduler is currently suspended - do not allow a context\r
1490                 switch. */\r
1491                 xMissedYield = pdTRUE;\r
1492                 return;\r
1493         }\r
1494 \r
1495         /* Find the highest priority queue that contains ready tasks. */\r
1496         while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )\r
1497         {\r
1498                 --uxTopReadyPriority;\r
1499         }\r
1500 \r
1501         /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the\r
1502         same priority get an equal share of the processor time. */\r
1503         listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );\r
1504         vWriteTraceToBuffer();\r
1505 }\r
1506 /*-----------------------------------------------------------*/\r
1507 \r
1508 void vTaskPlaceOnEventList( const xList * const pxEventList, portTickType xTicksToWait )\r
1509 {\r
1510 portTickType xTimeToWake;\r
1511 \r
1512         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1513         SCHEDULER SUSPENDED. */\r
1514 \r
1515         /* Place the event list item of the TCB in the appropriate event list.\r
1516         This is placed in the list in priority order so the highest priority task\r
1517         is the first to be woken by the event. */\r
1518         vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );\r
1519 \r
1520         /* We must remove ourselves from the ready list before adding ourselves\r
1521         to the blocked list as the same list item is used for both lists.  We have\r
1522         exclusive access to the ready lists as the scheduler is locked. */\r
1523         vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1524 \r
1525 \r
1526         #if ( INCLUDE_vTaskSuspend == 1 )\r
1527         {                        \r
1528                 if( xTicksToWait == portMAX_DELAY )\r
1529                 {\r
1530                         /* Add ourselves to the suspended task list instead of a delayed task\r
1531                         list to ensure we are not woken by a timing event.  We will block\r
1532                         indefinitely. */\r
1533                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1534                 }\r
1535                 else\r
1536                 {\r
1537                         /* Calculate the time at which the task should be woken if the event does\r
1538                         not occur.  This may overflow but this doesn't matter. */\r
1539                         xTimeToWake = xTickCount + xTicksToWait;\r
1540                 \r
1541                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1542                 \r
1543                         if( xTimeToWake < xTickCount )\r
1544                         {\r
1545                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1546                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1547                         }\r
1548                         else\r
1549                         {\r
1550                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1551                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1552                         }\r
1553                 }\r
1554         }\r
1555         #else\r
1556         {\r
1557                         /* Calculate the time at which the task should be woken if the event does\r
1558                         not occur.  This may overflow but this doesn't matter. */\r
1559                         xTimeToWake = xTickCount + xTicksToWait;\r
1560                 \r
1561                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1562                 \r
1563                         if( xTimeToWake < xTickCount )\r
1564                         {\r
1565                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1566                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1567                         }\r
1568                         else\r
1569                         {\r
1570                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1571                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1572                         }\r
1573         }\r
1574         #endif\r
1575 }\r
1576 /*-----------------------------------------------------------*/\r
1577 \r
1578 signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList )\r
1579 {\r
1580 tskTCB *pxUnblockedTCB;\r
1581 portBASE_TYPE xReturn;\r
1582 \r
1583         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1584         SCHEDULER SUSPENDED.  It can also be called from within an ISR. */\r
1585 \r
1586         /* The event list is sorted in priority order, so we can remove the\r
1587         first in the list, remove the TCB from the delayed list, and add\r
1588         it to the ready list.\r
1589         \r
1590         If an event is for a queue that is locked then this function will never\r
1591         get called - the lock count on the queue will get modified instead.  This\r
1592         means we can always expect exclusive access to the event list here. */\r
1593         pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );\r
1594         vListRemove( &( pxUnblockedTCB->xEventListItem ) );\r
1595 \r
1596         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1597         {\r
1598                 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );\r
1599                 prvAddTaskToReadyQueue( pxUnblockedTCB );\r
1600         }\r
1601         else\r
1602         {\r
1603                 /* We cannot access the delayed or ready lists, so will hold this\r
1604                 task pending until the scheduler is resumed. */\r
1605                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );\r
1606         }\r
1607 \r
1608         if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1609         {\r
1610                 /* Return true if the task removed from the event list has\r
1611                 a higher priority than the calling task.  This allows\r
1612                 the calling task to know if it should force a context\r
1613                 switch now. */\r
1614                 xReturn = pdTRUE;\r
1615         }\r
1616         else\r
1617         {\r
1618                 xReturn = pdFALSE;\r
1619         }\r
1620 \r
1621         return xReturn;\r
1622 }\r
1623 /*-----------------------------------------------------------*/\r
1624 \r
1625 void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut )\r
1626 {\r
1627     pxTimeOut->xOverflowCount = xNumOfOverflows;\r
1628     pxTimeOut->xTimeOnEntering = xTickCount;\r
1629 }\r
1630 /*-----------------------------------------------------------*/\r
1631 \r
1632 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait )\r
1633 {\r
1634 portBASE_TYPE xReturn;\r
1635 \r
1636         #if ( INCLUDE_vTaskSuspend == 1 )\r
1637                 /* If INCLUDE_vTaskSuspend is set to 1 and the block time specified is\r
1638                 the maximum block time then the task should block indefinitely, and\r
1639                 therefore never time out. */\r
1640                 if( *pxTicksToWait == portMAX_DELAY )\r
1641                 {\r
1642                         xReturn = pdFALSE;\r
1643                 }\r
1644                 else /* We are not blocking indefinitely, perform the checks below. */\r
1645         #endif\r
1646 \r
1647     if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )\r
1648     {\r
1649         /* The tick count is greater than the time at which vTaskSetTimeout()\r
1650                 was called, but has also overflowed since vTaskSetTimeOut() was called.\r
1651         It must have wrapped all the way around and gone past us again. This\r
1652         passed since vTaskSetTimeout() was called. */\r
1653         xReturn = pdTRUE;\r
1654     }\r
1655     else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )\r
1656     {\r
1657         /* Not a genuine timeout. Adjust parameters for time remaining. */\r
1658         *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );\r
1659         vTaskSetTimeOutState( pxTimeOut );\r
1660         xReturn = pdFALSE;\r
1661     }\r
1662     else\r
1663     {\r
1664         xReturn = pdTRUE;\r
1665     }\r
1666 \r
1667     return xReturn;\r
1668 }\r
1669 /*-----------------------------------------------------------*/\r
1670 \r
1671 void vTaskMissedYield( void )\r
1672 {\r
1673         xMissedYield = pdTRUE;\r
1674 }\r
1675 \r
1676 /*\r
1677  * -----------------------------------------------------------\r
1678  * The Idle task.\r
1679  * ----------------------------------------------------------\r
1680  *\r
1681  * The portTASK_FUNCTION() macro is used to allow port/compiler specific\r
1682  * language extensions.  The equivalent prototype for this function is:\r
1683  *\r
1684  * void prvIdleTask( void *pvParameters );\r
1685  *\r
1686  */\r
1687 static portTASK_FUNCTION( prvIdleTask, pvParameters )\r
1688 {\r
1689         /* Stop warnings. */\r
1690         ( void ) pvParameters;\r
1691 \r
1692         for( ;; )\r
1693         {\r
1694                 /* See if any tasks have been deleted. */\r
1695                 prvCheckTasksWaitingTermination();\r
1696 \r
1697                 #if ( configUSE_PREEMPTION == 0 )\r
1698                 {\r
1699                         /* If we are not using preemption we keep forcing a task switch to\r
1700                         see if any other task has become available.  If we are using\r
1701                         preemption we don't need to do this as any task becoming available\r
1702                         will automatically get the processor anyway. */\r
1703                         taskYIELD();    \r
1704                 }\r
1705                 #endif\r
1706 \r
1707                 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )\r
1708                 {\r
1709                         /* When using preemption tasks of equal priority will be\r
1710                         timesliced.  If a task that is sharing the idle priority is ready\r
1711                         to run then the idle task should yield before the end of the\r
1712                         timeslice.\r
1713                         \r
1714                         A critical region is not required here as we are just reading from\r
1715                         the list, and an occasional incorrect value will not matter.  If\r
1716                         the ready list at the idle priority contains more than one task\r
1717                         then a task other than the idle task is ready to execute. */\r
1718                         if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )\r
1719                         {\r
1720                                 taskYIELD();\r
1721                         }\r
1722                 }\r
1723                 #endif\r
1724 \r
1725                 #if ( configUSE_IDLE_HOOK == 1 )\r
1726                 {\r
1727                         extern void vApplicationIdleHook( void );\r
1728 \r
1729                         /* Call the user defined function from within the idle task.  This\r
1730                         allows the application designer to add background functionality\r
1731                         without the overhead of a separate task.\r
1732                         NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,\r
1733                         CALL A FUNCTION THAT MIGHT BLOCK. */\r
1734                         vApplicationIdleHook();\r
1735                 }\r
1736                 #endif\r
1737         }\r
1738 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */\r
1739 \r
1740 \r
1741 \r
1742 \r
1743 \r
1744 \r
1745 \r
1746 /*-----------------------------------------------------------\r
1747  * File private functions documented at the top of the file.\r
1748  *----------------------------------------------------------*/\r
1749 \r
1750 \r
1751 \r
1752 static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )\r
1753 {\r
1754         /* Store the function name in the TCB. */\r
1755         strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );\r
1756         pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';\r
1757 \r
1758         /* This is used as an array index so must ensure it's not too large. */\r
1759         if( uxPriority >= configMAX_PRIORITIES )\r
1760         {\r
1761                 uxPriority = configMAX_PRIORITIES - 1;\r
1762         }\r
1763 \r
1764         pxTCB->uxPriority = uxPriority;\r
1765         #if ( configUSE_MUTEXES == 1 )\r
1766         {\r
1767                 pxTCB->uxBasePriority = uxPriority;\r
1768         }\r
1769         #endif\r
1770 \r
1771         vListInitialiseItem( &( pxTCB->xGenericListItem ) );\r
1772         vListInitialiseItem( &( pxTCB->xEventListItem ) );\r
1773 \r
1774         /* Set the pxTCB as a link back from the xListItem.  This is so we can get\r
1775         back to the containing TCB from a generic item in a list. */\r
1776         listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );\r
1777 \r
1778         /* Event lists are always in priority order. */\r
1779         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );\r
1780         listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );\r
1781 }\r
1782 /*-----------------------------------------------------------*/\r
1783 \r
1784 static void prvInitialiseTaskLists( void )\r
1785 {\r
1786 unsigned portBASE_TYPE uxPriority;\r
1787 \r
1788         for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )\r
1789         {\r
1790                 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );\r
1791         }\r
1792 \r
1793         vListInitialise( ( xList * ) &xDelayedTaskList1 );\r
1794         vListInitialise( ( xList * ) &xDelayedTaskList2 );\r
1795         vListInitialise( ( xList * ) &xPendingReadyList );\r
1796 \r
1797         #if ( INCLUDE_vTaskDelete == 1 )\r
1798         {\r
1799                 vListInitialise( ( xList * ) &xTasksWaitingTermination );\r
1800         }\r
1801         #endif\r
1802 \r
1803         #if ( INCLUDE_vTaskSuspend == 1 )\r
1804         {\r
1805                 vListInitialise( ( xList * ) &xSuspendedTaskList );\r
1806         }\r
1807         #endif\r
1808 \r
1809         /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList\r
1810         using list2. */\r
1811         pxDelayedTaskList = &xDelayedTaskList1;\r
1812         pxOverflowDelayedTaskList = &xDelayedTaskList2;\r
1813 }\r
1814 /*-----------------------------------------------------------*/\r
1815 \r
1816 static void prvCheckTasksWaitingTermination( void )\r
1817 {                                                       \r
1818         #if ( INCLUDE_vTaskDelete == 1 )\r
1819         {                               \r
1820                 portBASE_TYPE xListIsEmpty;\r
1821 \r
1822                 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called\r
1823                 too often in the idle task. */\r
1824                 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )\r
1825                 {\r
1826                         vTaskSuspendAll();\r
1827                                 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );                          \r
1828                         xTaskResumeAll();\r
1829 \r
1830                         if( !xListIsEmpty )\r
1831                         {\r
1832                                 tskTCB *pxTCB;\r
1833 \r
1834                                 portENTER_CRITICAL();\r
1835                                 {                       \r
1836                                         pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );\r
1837                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1838                                         --uxCurrentNumberOfTasks;\r
1839                                         --uxTasksDeleted;\r
1840                                 }\r
1841                                 portEXIT_CRITICAL();\r
1842 \r
1843                                 prvDeleteTCB( pxTCB );\r
1844                         }\r
1845                 }\r
1846         }\r
1847         #endif\r
1848 }\r
1849 /*-----------------------------------------------------------*/\r
1850 \r
1851 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )\r
1852 {\r
1853 tskTCB *pxNewTCB;\r
1854 \r
1855         /* Allocate space for the TCB.  Where the memory comes from depends on\r
1856         the implementation of the port malloc function. */\r
1857         pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );\r
1858 \r
1859         if( pxNewTCB != NULL )\r
1860         {\r
1861                 /* Allocate space for the stack used by the task being created.\r
1862                 The base of the stack memory stored in the TCB so the task can\r
1863                 be deleted later if required. */\r
1864                 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );\r
1865 \r
1866                 if( pxNewTCB->pxStack == NULL )\r
1867                 {\r
1868                         /* Could not allocate the stack.  Delete the allocated TCB. */\r
1869                         vPortFree( pxNewTCB );                  \r
1870                         pxNewTCB = NULL;                        \r
1871                 }               \r
1872                 else\r
1873                 {\r
1874                         /* Just to help debugging. */\r
1875                         memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );\r
1876                 }\r
1877         }\r
1878 \r
1879         return pxNewTCB;\r
1880 }\r
1881 /*-----------------------------------------------------------*/\r
1882 \r
1883 #if ( configUSE_TRACE_FACILITY == 1 )\r
1884 \r
1885         static void prvListTaskWithinSingleList( const signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )\r
1886         {\r
1887         volatile tskTCB *pxNextTCB, *pxFirstTCB;\r
1888         static portCHAR pcStatusString[ 50 ];\r
1889         unsigned portSHORT usStackRemaining;\r
1890 \r
1891                 /* Write the details of all the TCB's in pxList into the buffer. */\r
1892                 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );\r
1893                 do\r
1894                 {\r
1895                         listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );\r
1896                         usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );\r
1897                         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
1898                         strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );\r
1899 \r
1900                 } while( pxNextTCB != pxFirstTCB );\r
1901         }\r
1902 \r
1903 #endif\r
1904 /*-----------------------------------------------------------*/\r
1905 \r
1906 #if ( configUSE_TRACE_FACILITY == 1 )\r
1907         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR * pucStackByte )\r
1908         {\r
1909         register unsigned portSHORT usCount = 0;\r
1910 \r
1911                 while( *pucStackByte == tskSTACK_FILL_BYTE )\r
1912                 {\r
1913                         pucStackByte -= portSTACK_GROWTH;\r
1914                         usCount++;\r
1915                 }\r
1916 \r
1917                 usCount /= sizeof( portSTACK_TYPE );\r
1918 \r
1919                 return usCount;\r
1920         }\r
1921 #endif\r
1922 /*-----------------------------------------------------------*/\r
1923 \r
1924 \r
1925 \r
1926 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
1927 \r
1928         static void prvDeleteTCB( tskTCB *pxTCB )\r
1929         {\r
1930                 /* Free up the memory allocated by the scheduler for the task.  It is up to\r
1931                 the task to free any memory allocated at the application level. */\r
1932                 vPortFree( pxTCB->pxStack );\r
1933                 vPortFree( pxTCB );\r
1934         }\r
1935 \r
1936 #endif\r
1937 \r
1938 \r
1939 /*-----------------------------------------------------------*/\r
1940 \r
1941 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )\r
1942 \r
1943         xTaskHandle xTaskGetCurrentTaskHandle( void )\r
1944         {\r
1945         xTaskHandle xReturn;\r
1946 \r
1947                 portENTER_CRITICAL();\r
1948                 {\r
1949                         xReturn = ( xTaskHandle ) pxCurrentTCB;\r
1950                 }\r
1951                 portEXIT_CRITICAL();\r
1952 \r
1953                 return xReturn;\r
1954         }\r
1955 \r
1956 #endif\r
1957 \r
1958 /*-----------------------------------------------------------*/\r
1959 \r
1960 #if ( INCLUDE_xTaskGetSchedulerState == 1 )\r
1961 \r
1962         portBASE_TYPE xTaskGetSchedulerState( void )\r
1963         {\r
1964         portBASE_TYPE xReturn;\r
1965         \r
1966                 if( xSchedulerRunning == pdFALSE )\r
1967                 {\r
1968                         xReturn = taskSCHEDULER_NOT_STARTED;\r
1969                 }\r
1970                 else\r
1971                 {\r
1972                         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1973                         {\r
1974                                 xReturn = taskSCHEDULER_RUNNING;\r
1975                         }\r
1976                         else\r
1977                         {\r
1978                                 xReturn = taskSCHEDULER_SUSPENDED;\r
1979                         }\r
1980                 }\r
1981                 \r
1982                 return xReturn;\r
1983         }\r
1984 \r
1985 #endif\r
1986 \r
1987 #if ( configUSE_MUTEXES == 1 )\r
1988         \r
1989         void vTaskPriorityInherit( xTaskHandle * const pxMutexHolder )\r
1990         {\r
1991         tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;\r
1992 \r
1993                 if( pxTCB->uxPriority < pxCurrentTCB->uxPriority )\r
1994                 {\r
1995                         /* Adjust the mutex holder state to account for its new priority. */\r
1996                         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxCurrentTCB->uxPriority );\r
1997 \r
1998                         /* If the task being modified is in the ready state it will need to\r
1999                         be moved in to a new list. */\r
2000                         if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
2001                         {\r
2002                                 vListRemove( &( pxTCB->xGenericListItem ) );\r
2003 \r
2004                                 /* Inherit the priority before being moved into the new list. */\r
2005                                 pxTCB->uxPriority = pxCurrentTCB->uxPriority;\r
2006                                 prvAddTaskToReadyQueue( pxTCB );\r
2007                         }\r
2008                         else\r
2009                         {\r
2010                                 /* Just inherit the priority. */\r
2011                                 pxTCB->uxPriority = pxCurrentTCB->uxPriority;\r
2012                         }\r
2013                 }\r
2014         }\r
2015 \r
2016 #endif\r
2017 \r
2018 #if ( configUSE_MUTEXES == 1 )  \r
2019 \r
2020         void vTaskPriorityDisinherit( xTaskHandle * const pxMutexHolder )\r
2021         {\r
2022         tskTCB * const pxTCB = ( tskTCB * ) pxMutexHolder;\r
2023 \r
2024                 if( pxMutexHolder != NULL )\r
2025                 {\r
2026                         if( pxTCB->uxPriority != pxTCB->uxBasePriority )\r
2027                         {\r
2028                                 /* We must be the running task to be able to give the mutex back.\r
2029                                 Remove ourselves from the ready list we currently appear in. */\r
2030                                 vListRemove( &( pxTCB->xGenericListItem ) );\r
2031 \r
2032                                 /* Disinherit the priority before adding ourselves into the new\r
2033                                 ready list. */\r
2034                                 pxTCB->uxPriority = pxTCB->uxBasePriority;\r
2035                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) pxTCB->uxPriority );\r
2036                                 prvAddTaskToReadyQueue( pxTCB );\r
2037                         }\r
2038                 }\r
2039         }\r
2040 \r
2041 #endif\r
2042 \r
2043         \r
2044 \r
2045         \r
2046 \r