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

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