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

   1 /*\r
   2         FreeRTOS.org V4.3.1 - 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         Also see http://www.SafeRTOS.com for an IEC 61508 compliant version, along\r
  32         with development and support options.\r
  33         ***************************************************************************\r
  34 */\r
  35 \r
  36 /*\r
  37 Changes from V1.00:\r
  38         \r
  39         + Call to portRESTORE_CONTEXT has been removed.  The first context\r
  40           switch is now performed within sPortStartScheduler().\r
  41 \r
  42 Changes from V1.01:\r
  43 \r
  44         + More use of 8bit data types.\r
  45         + Function name prefixes changed where the data type returned has changed.\r
  46         + configUSE_TRACE_FACILITY is no longer defined by default.\r
  47 \r
  48 Changes from V1.2.0\r
  49 \r
  50         + Introduced ucTopReadyPriority.  This tracks the highest priority ready\r
  51           queue that contains a valid TCB and thus makes the context switch\r
  52           slightly faster.\r
  53 \r
  54         + prvAddTaskToReadyQueue() has been made a macro.\r
  55 \r
  56 Changes from V1.2.6\r
  57 \r
  58         + Added conditional compilation directives.\r
  59         + Extended API.\r
  60         + Rearranged function order.\r
  61         + Creating a task now causes a context switch if the task being created\r
  62           has a higher priority than the calling task - assuming the kernel is\r
  63           running.\r
  64         + vTaskDelete() now only causes a context switch if the calling task is\r
  65           the task being deleted.\r
  66 \r
  67 Changes from V2.0.0\r
  68 \r
  69         + Allow the type of the tick count to be 16 or 32 bits.\r
  70         + Introduce xPendingReadyList feature to allow the time interrupts have to\r
  71           be disabled to be minimised.\r
  72         + Remove the #if( INCLUDE_vTaskSuspendAll ) statements.  vTaskSuspendAll()\r
  73           is now always included as it is used by the scheduler itself.\r
  74 \r
  75 Changes from V2.1.0\r
  76 \r
  77         + Bug fix - pxCurrentTCB is now initialised before the call to\r
  78           prvInitializeTaskLists().  Previously pxCurrentTCB could be accessed\r
  79           while null.\r
  80 \r
  81 Changed from V2.1.1\r
  82 \r
  83         + Change to where lStackSize is declared within sTaskCreate() to prevent\r
  84           compiler warnings with 8051 port.\r
  85 \r
  86 Changes from V2.2.0\r
  87 \r
  88         + Explicit use of 'signed' qualifier on portCHAR types added.\r
  89         + Changed odd calculation of initial pxTopOfStack value when\r
  90           portSTACK_GROWTH < 0.\r
  91         + Removed pcVersionNumber definition.\r
  92 \r
  93 Changes from V2.5.3\r
  94 \r
  95         + cTaskResumeAll() modified to ensure it can be called prior to the task\r
  96           lists being initialised.\r
  97 \r
  98 Changes from V2.5.5\r
  99 \r
 100         + Added API function vTaskDelayUntil().\r
 101         + Added INCLUDE_vTaskDelay conditional compilation.\r
 102 \r
 103 Changes from V2.6.0\r
 104 \r
 105         + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it\r
 106           can be used on ARM architectures.\r
 107         + tskMAX_TASK_NAME_LEN definition replaced with the port specific\r
 108           configMAX_TASK_NAME_LEN definition.\r
 109         + Removed the call to strcpy when copying across the task name into the\r
 110           TCB.\r
 111         + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called\r
 112           too often in the idle task.\r
 113 \r
 114 Changes between V3.0.0 and V2.6.1\r
 115 \r
 116         + When resuming the scheduler a yield is performed if either a tick has\r
 117           been missed, or a task is moved from the pending ready list into a ready\r
 118           list.  Previously a yield was not performed on this second condition.\r
 119         + Introduced the type portBASE_TYPE.  This necessitates several API\r
 120           changes.\r
 121         + Removed the sUsingPreemption variable.  The constant defined in\r
 122           portmacro.h is now used directly.\r
 123         + The idle task can now include an optional hook function - and no longer\r
 124           completes its time slice if other tasks with equal priority to it are\r
 125           ready to run.\r
 126         + See the FreeRTOS.org documentation for more information on V2.x.x to\r
 127           V3.x.x modifications.\r
 128 \r
 129 Changes from V3.1.1\r
 130 \r
 131         + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to\r
 132           be called while the scheduler is suspended.\r
 133         + Corrected the task ordering within event lists.\r
 134 \r
 135 Changes from V3.2.0\r
 136 \r
 137         + Added function xTaskGetCurrentTaskHandle().\r
 138 \r
 139 Changes from V3.2.4\r
 140 \r
 141         + Changed the volatile declarations on some variables to reflect the \r
 142           changes to the list definitions.\r
 143         + Changed the order of the TCB definition so there is commonality between\r
 144           the task control block and a co-routine control block.\r
 145         + Allow the scheduler to be started even if no tasks other than the idle\r
 146           task has been created.  This allows co-routines to run even when no tasks\r
 147           have been created.\r
 148         + The need for a context switch is now signalled if a task woken by an \r
 149           event has a priority greater or equal to the currently running task.\r
 150           Previously this was only greater than.\r
 151 \r
 152 Changes from V4.0.0\r
 153 \r
 154         + Added the xMissedYield handling.\r
 155 \r
 156 Changes from V4.0.1\r
 157 \r
 158         + The function vTaskList() now suspends the scheduler rather than disabling\r
 159           interrupts during the creation of the task list.  \r
 160         + Allow a task to delete itself by passing in its own handle.  Previously \r
 161           this could only be done by passing in NULL.\r
 162         + The tick hook function is now called only within a tick isr.  Previously\r
 163           it was also called when the tick function was called during the scheduler\r
 164           unlocking process.\r
 165 \r
 166 Changes from V4.0.3\r
 167 \r
 168         + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary\r
 169           yields.\r
 170 \r
 171 Changed from V4.0.4\r
 172 \r
 173         + Bug fix:  The 'value' of the event list item is updated when the priority\r
 174           of a task is changed.  Previously only the priority of the TCB itself was\r
 175           changed.\r
 176         + When resuming a task a check is first made to see if the task is actually\r
 177           suspended.\r
 178         + vTaskPrioritySet() and vTaskResume() no longer use the event list item.\r
 179           This has not been necessary since V4.0.1 when the xMissedYield handling\r
 180           was added.\r
 181         + Implement xTaskResumeFromISR().\r
 182 \r
 183 Changes from V4.0.5\r
 184 \r
 185         + Added utility functions and xOverflowCount variable to facilitate the\r
 186           queue.c changes.\r
 187 \r
 188 Changes from V4.1.2\r
 189         \r
 190         + Tasks that block on events with a timeout of portMAX_DELAY are now\r
 191           blocked indefinitely if configINCLUDE_vTaskSuspend is defined. \r
 192           Previously portMAX_DELAY was just the longest block time possible.\r
 193 \r
 194 Changes from V4.1.3\r
 195 \r
 196         + Very small change made to xTaskCheckForTimeout() as a result of the \r
 197         SafeRTOS testing.  This corrects the case where the function can return an\r
 198         invalid value - but only in an extremely unlikely scenario.\r
 199 */\r
 200 \r
 201 #include <stdio.h>\r
 202 #include <stdlib.h>\r
 203 #include <string.h>\r
 204 \r
 205 #include "FreeRTOS.h"\r
 206 #include "task.h"\r
 207 \r
 208 /*\r
 209  * Macro to define the amount of stack available to the idle task.\r
 210  */\r
 211 #define tskIDLE_STACK_SIZE      configMINIMAL_STACK_SIZE\r
 212 \r
 213 \r
 214 /*\r
 215  * Default a definitions for backwards compatibility with old\r
 216  * portmacro.h files.\r
 217  */\r
 218 #ifndef configMAX_TASK_NAME_LEN\r
 219         #define configMAX_TASK_NAME_LEN 16\r
 220 #endif\r
 221 \r
 222 #ifndef INCLUDE_xTaskGetCurrentTaskHandle\r
 223         #define INCLUDE_xTaskGetCurrentTaskHandle 0\r
 224 #endif\r
 225 \r
 226 #ifndef configIDLE_SHOULD_YIELD\r
 227         #define configIDLE_SHOULD_YIELD         1\r
 228 #endif\r
 229 \r
 230 #if configMAX_TASK_NAME_LEN < 1\r
 231         #undef configMAX_TASK_NAME_LEN\r
 232         #define configMAX_TASK_NAME_LEN 1\r
 233 #endif\r
 234 \r
 235 #ifndef INCLUDE_xTaskResumeFromISR\r
 236         #define INCLUDE_xTaskResumeFromISR 1\r
 237 #endif \r
 238 \r
 239 /*\r
 240  * Task control block.  A task control block (TCB) is allocated to each task,\r
 241  * and stores the context of the task.\r
 242  */\r
 243 typedef struct tskTaskControlBlock\r
 244 {\r
 245         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
 246         xListItem                               xGenericListItem;       /*< List item used to place the TCB in ready and blocked queues. */\r
 247         xListItem                               xEventListItem;         /*< List item used to place the TCB in event lists. */\r
 248         unsigned portBASE_TYPE  uxPriority;                     /*< The priority of the task where 0 is the lowest priority. */\r
 249         portSTACK_TYPE                  *pxStack;                       /*< Points to the start of the stack. */\r
 250         unsigned portBASE_TYPE  uxTCBNumber;            /*< This is used for tracing the scheduler and making debugging easier only. */\r
 251         signed portCHAR                 pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */\r
 252         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
 253 } tskTCB;\r
 254 \r
 255 /*lint -e956 */\r
 256 \r
 257 tskTCB * volatile pxCurrentTCB = NULL;                                  \r
 258 \r
 259 /* Lists for ready and blocked tasks. --------------------*/\r
 260 \r
 261 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */\r
 262 static xList xDelayedTaskList1;                                                 /*< Delayed tasks. */\r
 263 static xList xDelayedTaskList2;                                                 /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */\r
 264 static xList * volatile pxDelayedTaskList;                              /*< Points to the delayed task list currently being used. */\r
 265 static xList * volatile pxOverflowDelayedTaskList;              /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */\r
 266 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
 267 \r
 268 #if ( INCLUDE_vTaskDelete == 1 )\r
 269 \r
 270         static volatile xList xTasksWaitingTermination;         /*< Tasks that have been deleted - but the their memory not yet freed. */\r
 271         static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;\r
 272 \r
 273 #endif\r
 274 \r
 275 #if ( INCLUDE_vTaskSuspend == 1 )\r
 276 \r
 277         static xList xSuspendedTaskList;                                        /*< Tasks that are currently suspended. */\r
 278 \r
 279 #endif\r
 280 \r
 281 /* File private variables. --------------------------------*/\r
 282 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks   = ( unsigned portBASE_TYPE ) 0;\r
 283 static volatile portTickType xTickCount                                                 = ( portTickType ) 0;\r
 284 static unsigned portBASE_TYPE uxTopUsedPriority                                 = tskIDLE_PRIORITY;\r
 285 static volatile unsigned portBASE_TYPE uxTopReadyPriority               = tskIDLE_PRIORITY;\r
 286 static volatile signed portBASE_TYPE xSchedulerRunning                  = pdFALSE;\r
 287 static volatile unsigned portBASE_TYPE uxSchedulerSuspended             = ( unsigned portBASE_TYPE ) pdFALSE;\r
 288 static volatile unsigned portBASE_TYPE uxMissedTicks                    = ( unsigned portBASE_TYPE ) 0;\r
 289 static volatile portBASE_TYPE xMissedYield                                              = ( portBASE_TYPE ) pdFALSE;\r
 290 static volatile portBASE_TYPE xNumOfOverflows                                   = ( portBASE_TYPE ) 0;\r
 291 /* Debugging and trace facilities private variables and macros. ------------*/\r
 292 \r
 293 /*\r
 294  * The value used to fill the stack of a task when the task is created.  This\r
 295  * is used purely for checking the high water mark for tasks.\r
 296  */\r
 297 #define tskSTACK_FILL_BYTE      ( 0xa5 )\r
 298 \r
 299 /*\r
 300  * Macros used by vListTask to indicate which state a task is in.\r
 301  */\r
 302 #define tskBLOCKED_CHAR         ( ( signed portCHAR ) 'B' )\r
 303 #define tskREADY_CHAR           ( ( signed portCHAR ) 'R' )\r
 304 #define tskDELETED_CHAR         ( ( signed portCHAR ) 'D' )\r
 305 #define tskSUSPENDED_CHAR       ( ( signed portCHAR ) 'S' )\r
 306 \r
 307 /*\r
 308  * Macros and private variables used by the trace facility.\r
 309  */\r
 310 #if ( configUSE_TRACE_FACILITY == 1 )\r
 311 \r
 312         #define tskSIZE_OF_EACH_TRACE_LINE                      ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )\r
 313         static volatile signed portCHAR * volatile pcTraceBuffer;\r
 314         static signed portCHAR *pcTraceBufferStart;\r
 315         static signed portCHAR *pcTraceBufferEnd;\r
 316         static signed portBASE_TYPE xTracing = pdFALSE;\r
 317 \r
 318 #endif\r
 319 \r
 320 /*\r
 321  * Macro that writes a trace of scheduler activity to a buffer.  This trace\r
 322  * shows which task is running when and is very useful as a debugging tool.\r
 323  * As this macro is called each context switch it is a good idea to undefine\r
 324  * it if not using the facility.\r
 325  */\r
 326 #if ( configUSE_TRACE_FACILITY == 1 )\r
 327 \r
 328         #define vWriteTraceToBuffer()                                                                                                                                   \\r
 329         {                                                                                                                                                                                               \\r
 330                 if( xTracing )                                                                                                                                                          \\r
 331                 {                                                                                                                                                                                       \\r
 332                         static unsigned portBASE_TYPE uxPreviousTask = 255;                                                                             \\r
 333                                                                                                                                                                                                         \\r
 334                         if( uxPreviousTask != pxCurrentTCB->uxTCBNumber )                                                                               \\r
 335                         {                                                                                                                                                                               \\r
 336                                 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd )                         \\r
 337                                 {                                                                                                                                                                       \\r
 338                                         uxPreviousTask = pxCurrentTCB->uxTCBNumber;                                                                             \\r
 339                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount;              \\r
 340                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 341                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask;  \\r
 342                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 343                                 }                                                                                                                                                                       \\r
 344                                 else                                                                                                                                                            \\r
 345                                 {                                                                                                                                                                       \\r
 346                                         xTracing = pdFALSE;                                                                                                                             \\r
 347                                 }                                                                                                                                                                       \\r
 348                         }                                                                                                                                                                               \\r
 349                 }                                                                                                                                                                                       \\r
 350         }\r
 351 \r
 352 #else\r
 353 \r
 354         #define vWriteTraceToBuffer()\r
 355 \r
 356 #endif\r
 357 \r
 358 \r
 359 /*\r
 360  * Place the task represented by pxTCB into the appropriate ready queue for\r
 361  * the task.  It is inserted at the end of the list.  One quirk of this is\r
 362  * that if the task being inserted is at the same priority as the currently\r
 363  * executing task, then it will only be rescheduled after the currently\r
 364  * executing task has been rescheduled.\r
 365  */\r
 366 #define prvAddTaskToReadyQueue( pxTCB )                                                                                                                                                 \\r
 367 {                                                                                                                                                                                                                               \\r
 368         if( pxTCB->uxPriority > uxTopReadyPriority )                                                                                                                            \\r
 369         {                                                                                                                                                                                                                       \\r
 370                 uxTopReadyPriority = pxTCB->uxPriority;                                                                                                                                 \\r
 371         }                                                                                                                                                                                                                       \\r
 372         vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) );        \\r
 373 }               \r
 374 \r
 375 /*\r
 376  * Macro that looks at the list of tasks that are currently delayed to see if\r
 377  * any require waking.\r
 378  *\r
 379  * Tasks are stored in the queue in the order of their wake time - meaning\r
 380  * once one tasks has been found whose timer has not expired we need not look\r
 381  * any further down the list.\r
 382  */\r
 383 #define prvCheckDelayedTasks()                                                                                                                                                                          \\r
 384 {                                                                                                                                                                                                                                       \\r
 385 register tskTCB *pxTCB;                                                                                                                                                                                         \\r
 386                                                                                                                                                                                                                                         \\r
 387         while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL )                                              \\r
 388         {                                                                                                                                                                                                                               \\r
 389                 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) )                                                                      \\r
 390                 {                                                                                                                                                                                                                       \\r
 391                         break;                                                                                                                                                                                                  \\r
 392                 }                                                                                                                                                                                                                       \\r
 393                 vListRemove( &( pxTCB->xGenericListItem ) );                                                                                                                            \\r
 394                 /* Is the task waiting on an event also? */                                                                                                                                     \\r
 395                 if( pxTCB->xEventListItem.pvContainer )                                                                                                                                         \\r
 396                 {                                                                                                                                                                                                                       \\r
 397                         vListRemove( &( pxTCB->xEventListItem ) );                                                                                                                              \\r
 398                 }                                                                                                                                                                                                                       \\r
 399                 prvAddTaskToReadyQueue( pxTCB );                                                                                                                \\r
 400         }                                                                                                                                                                                                                               \\r
 401 }                                                                                                                                                                                       \r
 402 \r
 403 /*\r
 404  * Several functions take an xTaskHandle parameter that can optionally be NULL,\r
 405  * where NULL is used to indicate that the handle of the currently executing\r
 406  * task should be used in place of the parameter.  This macro simply checks to\r
 407  * see if the parameter is NULL and returns a pointer to the appropriate TCB.\r
 408  */\r
 409 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )\r
 410 \r
 411 \r
 412 /* File private functions. --------------------------------*/\r
 413 \r
 414 /*\r
 415  * Utility to ready a TCB for a given task.  Mainly just copies the parameters\r
 416  * into the TCB structure.\r
 417  */\r
 418 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );\r
 419 \r
 420 /*\r
 421  * Utility to ready all the lists used by the scheduler.  This is called\r
 422  * automatically upon the creation of the first task.\r
 423  */\r
 424 static void prvInitialiseTaskLists( void );\r
 425 \r
 426 /*\r
 427  * The idle task, which as all tasks is implemented as a never ending loop.\r
 428  * The idle task is automatically created and added to the ready lists upon\r
 429  * creation of the first user task.\r
 430  *\r
 431  * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific\r
 432  * language extensions.  The equivalent prototype for this function is:\r
 433  *\r
 434  * void prvIdleTask( void *pvParameters );\r
 435  *\r
 436  */\r
 437 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );\r
 438 \r
 439 /*\r
 440  * Utility to free all memory allocated by the scheduler to hold a TCB,\r
 441  * including the stack pointed to by the TCB.\r
 442  *\r
 443  * This does not free memory allocated by the task itself (i.e. memory\r
 444  * allocated by calls to pvPortMalloc from within the tasks application code).\r
 445  */\r
 446 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
 447         static void prvDeleteTCB( tskTCB *pxTCB );\r
 448 #endif\r
 449 \r
 450 /*\r
 451  * Used only by the idle task.  This checks to see if anything has been placed\r
 452  * in the list of tasks waiting to be deleted.  If so the task is cleaned up\r
 453  * and its TCB deleted.\r
 454  */\r
 455 static void prvCheckTasksWaitingTermination( void );\r
 456 \r
 457 /*\r
 458  * Allocates memory from the heap for a TCB and associated stack.  Checks the\r
 459  * allocation was successful.\r
 460  */\r
 461 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );\r
 462 \r
 463 /*\r
 464  * Called from vTaskList.  vListTasks details all the tasks currently under\r
 465  * control of the scheduler.  The tasks may be in one of a number of lists.\r
 466  * prvListTaskWithinSingleList accepts a list and details the tasks from\r
 467  * within just that list.\r
 468  *\r
 469  * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM\r
 470  * NORMAL APPLICATION CODE.\r
 471  */\r
 472 #if ( configUSE_TRACE_FACILITY == 1 )\r
 473 \r
 474         static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );\r
 475 \r
 476 #endif\r
 477 \r
 478 /*\r
 479  * When a task is created, the stack of the task is filled with a known value.\r
 480  * This function determines the 'high water mark' of the task stack by\r
 481  * determining how much of the stack remains at the original preset value.\r
 482  */\r
 483 #if ( configUSE_TRACE_FACILITY == 1 )\r
 484 \r
 485         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );\r
 486 \r
 487 #endif\r
 488 \r
 489 /*lint +e956 */\r
 490 \r
 491 \r
 492 \r
 493 \r
 494 \r
 495 /*-----------------------------------------------------------\r
 496  * TASK CREATION API documented in task.h\r
 497  *----------------------------------------------------------*/\r
 498 \r
 499 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )\r
 500 {\r
 501 signed portBASE_TYPE xReturn;\r
 502 tskTCB * pxNewTCB;\r
 503 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */\r
 504 \r
 505         /* Allocate the memory required by the TCB and stack for the new task.\r
 506         checking that the allocation was successful. */\r
 507         pxNewTCB = prvAllocateTCBAndStack( usStackDepth );\r
 508 \r
 509         if( pxNewTCB != NULL )\r
 510         {               \r
 511                 portSTACK_TYPE *pxTopOfStack;\r
 512 \r
 513                 /* Setup the newly allocated TCB with the initial state of the task. */\r
 514                 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );\r
 515 \r
 516                 /* Calculate the top of stack address.  This depends on whether the\r
 517                 stack grows from high memory to low (as per the 80x86) or visa versa.\r
 518                 portSTACK_GROWTH is used to make the result positive or negative as\r
 519                 required by the port. */\r
 520                 #if portSTACK_GROWTH < 0\r
 521                 {\r
 522                         pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );\r
 523                 }\r
 524                 #else\r
 525                 {\r
 526                         pxTopOfStack = pxNewTCB->pxStack;       \r
 527                 }\r
 528                 #endif\r
 529 \r
 530                 /* Initialize the TCB stack to look as if the task was already running,\r
 531                 but had been interrupted by the scheduler.  The return address is set\r
 532                 to the start of the task function. Once the stack has been initialised\r
 533                 the     top of stack variable is updated. */\r
 534                 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );\r
 535 \r
 536                 /* We are going to manipulate the task queues to add this task to a\r
 537                 ready list, so must make sure no interrupts occur. */\r
 538                 portENTER_CRITICAL();\r
 539                 {\r
 540                         uxCurrentNumberOfTasks++;\r
 541                         if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )\r
 542                         {\r
 543                                 /* As this is the first task it must also be the current task. */\r
 544                                 pxCurrentTCB =  pxNewTCB;\r
 545 \r
 546                                 /* This is the first task to be created so do the preliminary\r
 547                                 initialisation required.  We will not recover if this call\r
 548                                 fails, but we will report the failure. */\r
 549                                 prvInitialiseTaskLists();\r
 550                         }\r
 551                         else\r
 552                         {       \r
 553                                 /* If the scheduler is not already running, make this task the\r
 554                                 current task if it is the highest priority task to be created\r
 555                                 so far. */\r
 556                                 if( xSchedulerRunning == pdFALSE )\r
 557                                 {\r
 558                                         if( pxCurrentTCB->uxPriority <= uxPriority )\r
 559                                         {\r
 560                                                 pxCurrentTCB = pxNewTCB;        \r
 561                                         }\r
 562                                 }\r
 563                         }                               \r
 564 \r
 565                         /* Remember the top priority to make context switching faster.  Use\r
 566                         the priority in pxNewTCB as this has been capped to a valid value. */\r
 567                         if( pxNewTCB->uxPriority > uxTopUsedPriority )\r
 568                         {\r
 569                                 uxTopUsedPriority = pxNewTCB->uxPriority;\r
 570                         }\r
 571 \r
 572                         /* Add a counter into the TCB for tracing only. */\r
 573                         pxNewTCB->uxTCBNumber = uxTaskNumber;\r
 574                         uxTaskNumber++;\r
 575 \r
 576                         prvAddTaskToReadyQueue( pxNewTCB );\r
 577 \r
 578                         xReturn = pdPASS;\r
 579                 }\r
 580                 portEXIT_CRITICAL();\r
 581         }\r
 582         else\r
 583         {\r
 584                 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;\r
 585         }\r
 586 \r
 587         if( xReturn == pdPASS )\r
 588         {\r
 589                 if( ( void * ) pxCreatedTask != NULL )\r
 590                 {\r
 591                         /* Pass the TCB out - in an anonymous way.  The calling function/\r
 592                         task can use this as a handle to delete the task later if\r
 593                         required.*/\r
 594                         *pxCreatedTask = ( xTaskHandle ) pxNewTCB;\r
 595                 }\r
 596 \r
 597                 if( xSchedulerRunning != pdFALSE )\r
 598                 {\r
 599                         /* If the created task is of a higher priority than the current task\r
 600                         then it should run now. */\r
 601                         if( pxCurrentTCB->uxPriority < uxPriority )\r
 602                         {\r
 603                                 taskYIELD();\r
 604                         }\r
 605                 }\r
 606         }\r
 607 \r
 608         return xReturn;\r
 609 }\r
 610 /*-----------------------------------------------------------*/\r
 611 \r
 612 #if ( INCLUDE_vTaskDelete == 1 )\r
 613 \r
 614         void vTaskDelete( xTaskHandle pxTaskToDelete )\r
 615         {\r
 616         tskTCB *pxTCB;\r
 617 \r
 618                 taskENTER_CRITICAL();\r
 619                 {\r
 620                         /* Ensure a yield is performed if the current task is being \r
 621                         deleted. */\r
 622                         if( pxTaskToDelete == pxCurrentTCB )\r
 623                         {\r
 624                                 pxTaskToDelete = NULL;\r
 625                         }\r
 626 \r
 627                         /* If null is passed in here then we are deleting ourselves. */\r
 628                         pxTCB = prvGetTCBFromHandle( pxTaskToDelete );\r
 629 \r
 630                         /* Remove task from the ready list and place in the     termination list.\r
 631                         This will stop the task from be scheduled.  The idle task will check\r
 632                         the termination list and free up any memory allocated by the\r
 633                         scheduler for the TCB and stack. */\r
 634                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 635 \r
 636                         /* Is the task waiting on an event also? */                                                                                             \r
 637                         if( pxTCB->xEventListItem.pvContainer )\r
 638                         {\r
 639                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 640                         }\r
 641 \r
 642                         vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );\r
 643 \r
 644                         /* Increment the ucTasksDeleted variable so the idle task knows\r
 645                         there is a task that has been deleted and that it should therefore\r
 646                         check the xTasksWaitingTermination list. */\r
 647                         ++uxTasksDeleted;\r
 648                 }\r
 649                 taskEXIT_CRITICAL();\r
 650 \r
 651                 /* Force a reschedule if we have just deleted the current task. */\r
 652                 if( xSchedulerRunning != pdFALSE ) \r
 653                 {\r
 654                         if( ( void * ) pxTaskToDelete == NULL )\r
 655                         {\r
 656                                 taskYIELD();\r
 657                         }\r
 658                 }\r
 659         }\r
 660 \r
 661 #endif\r
 662 \r
 663 \r
 664 \r
 665 \r
 666 \r
 667 \r
 668 /*-----------------------------------------------------------\r
 669  * TASK CONTROL API documented in task.h\r
 670  *----------------------------------------------------------*/\r
 671 \r
 672 #if ( INCLUDE_vTaskDelayUntil == 1 )\r
 673 \r
 674         void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )\r
 675         {\r
 676         portTickType xTimeToWake;\r
 677         portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;\r
 678 \r
 679                 vTaskSuspendAll();\r
 680                 {\r
 681                         /* Generate the tick time at which the task wants to wake. */\r
 682                         xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;\r
 683 \r
 684                         if( xTickCount < *pxPreviousWakeTime )\r
 685                         {\r
 686                                 /* The tick count has overflowed since this function was\r
 687                                 lasted called.  In this case the only time we should ever\r
 688                                 actually delay is if the wake time has also     overflowed,\r
 689                                 and the wake time is greater than the tick time.  When this\r
 690                                 is the case it is as if neither time had overflowed. */\r
 691                                 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )\r
 692                                 {\r
 693                                         xShouldDelay = pdTRUE;\r
 694                                 }\r
 695                         }\r
 696                         else\r
 697                         {\r
 698                                 /* The tick time has not overflowed.  In this case we will\r
 699                                 delay if either the wake time has overflowed, and/or the\r
 700                                 tick time is less than the wake time. */\r
 701                                 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )\r
 702                                 {\r
 703                                         xShouldDelay = pdTRUE;\r
 704                                 }\r
 705                         }\r
 706 \r
 707                         /* Update the wake time ready for the next call. */\r
 708                         *pxPreviousWakeTime = xTimeToWake;\r
 709 \r
 710                         if( xShouldDelay )\r
 711                         {\r
 712                                 /* We must remove ourselves from the ready list before adding\r
 713                                 ourselves to the blocked list as the same list item is used for\r
 714                                 both lists. */\r
 715                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 716 \r
 717                                 /* The list item will be inserted in wake time order. */\r
 718                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 719 \r
 720                                 if( xTimeToWake < xTickCount )\r
 721                                 {\r
 722                                         /* Wake time has overflowed.  Place this item in the\r
 723                                         overflow list. */\r
 724                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 725                                 }\r
 726                                 else\r
 727                                 {\r
 728                                         /* The wake time has not overflowed, so we can use the\r
 729                                         current block list. */\r
 730                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 731                                 }\r
 732                         }\r
 733                 }\r
 734                 xAlreadyYielded = xTaskResumeAll();\r
 735 \r
 736                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 737                 have put ourselves to sleep. */\r
 738                 if( !xAlreadyYielded )\r
 739                 {\r
 740                         taskYIELD();\r
 741                 }\r
 742         }       \r
 743         \r
 744 #endif\r
 745 /*-----------------------------------------------------------*/\r
 746 \r
 747 #if ( INCLUDE_vTaskDelay == 1 )\r
 748 \r
 749         void vTaskDelay( portTickType xTicksToDelay )\r
 750         {\r
 751         portTickType xTimeToWake;\r
 752         signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
 753 \r
 754                 /* A delay time of zero just forces a reschedule. */\r
 755                 if( xTicksToDelay > ( portTickType ) 0 )\r
 756                 {\r
 757                         vTaskSuspendAll();\r
 758                         {\r
 759                                 /* A task that is removed from the event list while the\r
 760                                 scheduler is suspended will not get placed in the ready\r
 761                                 list or removed from the blocked list until the scheduler\r
 762                                 is resumed.\r
 763                                 \r
 764                                 This task cannot be in an event list as it is the currently\r
 765                                 executing task. */\r
 766 \r
 767                                 /* Calculate the time to wake - this may overflow but this is\r
 768                                 not a problem. */\r
 769                                 xTimeToWake = xTickCount + xTicksToDelay;\r
 770 \r
 771                                 /* We must remove ourselves from the ready list before adding\r
 772                                 ourselves to the blocked list as the same list item is used for\r
 773                                 both lists. */\r
 774                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 775 \r
 776                                 /* The list item will be inserted in wake time order. */\r
 777                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 778 \r
 779                                 if( xTimeToWake < xTickCount )\r
 780                                 {\r
 781                                         /* Wake time has overflowed.  Place this item in the\r
 782                                         overflow list. */\r
 783                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 784                                 }\r
 785                                 else\r
 786                                 {\r
 787                                         /* The wake time has not overflowed, so we can use the\r
 788                                         current block list. */\r
 789                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 790                                 }\r
 791                         }\r
 792                         xAlreadyYielded = xTaskResumeAll();\r
 793                 }\r
 794                 \r
 795                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 796                 have put ourselves to sleep. */\r
 797                 if( !xAlreadyYielded )\r
 798                 {\r
 799                         taskYIELD();\r
 800                 }\r
 801         }\r
 802         \r
 803 #endif\r
 804 /*-----------------------------------------------------------*/\r
 805 \r
 806 #if ( INCLUDE_uxTaskPriorityGet == 1 )\r
 807 \r
 808         unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )\r
 809         {\r
 810         tskTCB *pxTCB;\r
 811         unsigned portBASE_TYPE uxReturn;\r
 812 \r
 813                 taskENTER_CRITICAL();\r
 814                 {\r
 815                         /* If null is passed in here then we are changing the\r
 816                         priority of the calling function. */\r
 817                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 818                         uxReturn = pxTCB->uxPriority;\r
 819                 }\r
 820                 taskEXIT_CRITICAL();\r
 821 \r
 822                 return uxReturn;\r
 823         }\r
 824 \r
 825 #endif\r
 826 /*-----------------------------------------------------------*/\r
 827 \r
 828 #if ( INCLUDE_vTaskPrioritySet == 1 )\r
 829 \r
 830         void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )\r
 831         {\r
 832         tskTCB *pxTCB;\r
 833         unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;\r
 834 \r
 835                 /* Ensure the new priority is valid. */\r
 836                 if( uxNewPriority >= configMAX_PRIORITIES )\r
 837                 {\r
 838                         uxNewPriority = configMAX_PRIORITIES - 1;\r
 839                 }\r
 840 \r
 841                 taskENTER_CRITICAL();\r
 842                 {\r
 843                         /* If null is passed in here then we are changing the\r
 844                         priority of the calling function. */\r
 845                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 846                         uxCurrentPriority = pxTCB->uxPriority;\r
 847 \r
 848                         if( uxCurrentPriority != uxNewPriority )\r
 849                         {\r
 850                                 /* The priority change may have readied a task of higher\r
 851                                 priority than the calling task. */\r
 852                                 if( uxNewPriority > pxCurrentTCB->uxPriority ) \r
 853                                 {\r
 854                                         if( pxTask != NULL )\r
 855                                         {\r
 856                                                 /* The priority of another task is being raised.  If we\r
 857                                                 were raising the priority of the currently running task\r
 858                                                 there would be no need to switch as it must have already\r
 859                                                 been the highest priority task. */\r
 860                                                 xYieldRequired = pdTRUE;\r
 861                                         }\r
 862                                 }\r
 863                                 else if( pxTask == NULL )\r
 864                                 {\r
 865                                         /* Setting our own priority down means there may now be another\r
 866                                         task of higher priority that is ready to execute. */\r
 867                                         xYieldRequired = pdTRUE;\r
 868                                 }\r
 869                         \r
 870                                 pxTCB->uxPriority = uxNewPriority;\r
 871                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );\r
 872 \r
 873                                 /* If the task is in the blocked or suspended list we need do\r
 874                                 nothing more than change it's priority variable. However, if\r
 875                                 the task is in a ready list it needs to be removed and placed\r
 876                                 in the queue appropriate to its new priority. */\r
 877                                 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
 878                                 {\r
 879                                         /* The task is currently in its ready list - remove before adding\r
 880                                         it to it's new ready list.  As we are in a critical section we\r
 881                                         can do this even if the scheduler is suspended. */\r
 882                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 883                                         prvAddTaskToReadyQueue( pxTCB );\r
 884                                 }                       \r
 885                                 \r
 886                                 if( xYieldRequired == pdTRUE )\r
 887                                 {\r
 888                                         taskYIELD();\r
 889                                 }                               \r
 890                         }\r
 891                 }\r
 892                 taskEXIT_CRITICAL();\r
 893         }\r
 894 \r
 895 #endif\r
 896 /*-----------------------------------------------------------*/\r
 897 \r
 898 #if ( INCLUDE_vTaskSuspend == 1 )\r
 899 \r
 900         void vTaskSuspend( xTaskHandle pxTaskToSuspend )\r
 901         {\r
 902         tskTCB *pxTCB;\r
 903 \r
 904                 taskENTER_CRITICAL();\r
 905                 {\r
 906                         /* Ensure a yield is performed if the current task is being \r
 907                         suspended. */\r
 908                         if( pxTaskToSuspend == pxCurrentTCB )\r
 909                         {\r
 910                                 pxTaskToSuspend = NULL;\r
 911                         }\r
 912 \r
 913                         /* If null is passed in here then we are suspending ourselves. */\r
 914                         pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );\r
 915 \r
 916                         /* Remove task from the ready/delayed list and place in the     suspended list. */\r
 917                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 918 \r
 919                         /* Is the task waiting on an event also? */                                                                                             \r
 920                         if( pxTCB->xEventListItem.pvContainer )\r
 921                         {\r
 922                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 923                         }\r
 924 \r
 925                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );\r
 926                 }\r
 927                 taskEXIT_CRITICAL();\r
 928 \r
 929                 /* We may have just suspended the current task. */\r
 930                 if( ( void * ) pxTaskToSuspend == NULL )\r
 931                 {\r
 932                         taskYIELD();\r
 933                 }\r
 934         }\r
 935 \r
 936 #endif\r
 937 /*-----------------------------------------------------------*/\r
 938 \r
 939 #if ( INCLUDE_vTaskSuspend == 1 )\r
 940 \r
 941         void vTaskResume( xTaskHandle pxTaskToResume )\r
 942         {\r
 943         tskTCB *pxTCB;\r
 944 \r
 945                 /* Remove the task from whichever list it is currently in, and place\r
 946                 it in the ready list. */\r
 947                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
 948 \r
 949                 /* The parameter cannot be NULL as it is impossible to resume the\r
 950                 currently executing task. */\r
 951                 if( pxTCB != NULL )\r
 952                 {\r
 953                         taskENTER_CRITICAL();\r
 954                         {\r
 955                                 /* Is the task we are attempting to resume actually suspended? */\r
 956                                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
 957                                 {\r
 958                                         /* Has the task already been resumed from within an ISR? */\r
 959                                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
 960                                         {                       \r
 961                                                 /* As we are in a critical section we can access the ready \r
 962                                                 lists even if the scheduler is suspended. */\r
 963                                                 vListRemove(  &( pxTCB->xGenericListItem ) );\r
 964                                                 prvAddTaskToReadyQueue( pxTCB );\r
 965 \r
 966                                                 /* We may have just resumed a higher priority task. */\r
 967                                                 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
 968                                                 {\r
 969                                                         /* This yield may not cause the task just resumed to run, but\r
 970                                                         will leave the lists in the correct state for the next yield. */\r
 971                                                         taskYIELD();\r
 972                                                 }\r
 973                                         }\r
 974                                 }\r
 975                         }\r
 976                         taskEXIT_CRITICAL();\r
 977                 }\r
 978         }\r
 979 \r
 980 #endif\r
 981 \r
 982 /*-----------------------------------------------------------*/\r
 983 \r
 984 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
 985 \r
 986         portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )\r
 987         {\r
 988         portBASE_TYPE xYieldRequired = pdFALSE;\r
 989         tskTCB *pxTCB;\r
 990 \r
 991                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
 992 \r
 993                 /* Is the task we are attempting to resume actually suspended? */\r
 994                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
 995                 {\r
 996                         /* Has the task already been resumed from within an ISR? */\r
 997                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
 998                         {\r
 999                                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1000                                 {\r
1001                                         xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );\r
1002                                         vListRemove(  &( pxTCB->xGenericListItem ) );   \r
1003                                         prvAddTaskToReadyQueue( pxTCB );\r
1004                                 }\r
1005                                 else\r
1006                                 {\r
1007                                         /* We cannot access the delayed or ready lists, so will hold this\r
1008                                         task pending until the scheduler is resumed, at which point a \r
1009                                         yield will be preformed if necessary. */\r
1010                                         vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );\r
1011                                 }\r
1012                         }\r
1013                 }\r
1014 \r
1015                 return xYieldRequired;\r
1016         }\r
1017 \r
1018 #endif\r
1019 \r
1020 \r
1021 \r
1022 \r
1023 /*-----------------------------------------------------------\r
1024  * PUBLIC SCHEDULER CONTROL documented in task.h\r
1025  *----------------------------------------------------------*/\r
1026 \r
1027 \r
1028 void vTaskStartScheduler( void )\r
1029 {\r
1030 portBASE_TYPE xReturn;\r
1031 \r
1032         /* Add the idle task at the lowest priority. */\r
1033         xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );\r
1034 \r
1035         if( xReturn == pdPASS )\r
1036         {\r
1037                 /* Interrupts are turned off here, to ensure a tick does not occur\r
1038                 before or during the call to xPortStartScheduler().  The stacks of\r
1039                 the created tasks contain a status word with interrupts switched on\r
1040                 so interrupts will automatically get re-enabled when the first task\r
1041                 starts to run.\r
1042                 \r
1043                 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE\r
1044                 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */\r
1045                 portDISABLE_INTERRUPTS();\r
1046 \r
1047                 xSchedulerRunning = pdTRUE;\r
1048                 xTickCount = ( portTickType ) 0;\r
1049 \r
1050                 /* Setting up the timer tick is hardware specific and thus in the\r
1051                 portable interface. */\r
1052                 if( xPortStartScheduler() )\r
1053                 {\r
1054                         /* Should not reach here as if the scheduler is running the\r
1055                         function will not return. */\r
1056                 }\r
1057                 else\r
1058                 {\r
1059                         /* Should only reach here if a task calls xTaskEndScheduler(). */\r
1060                 }\r
1061         }\r
1062 }\r
1063 /*-----------------------------------------------------------*/\r
1064 \r
1065 void vTaskEndScheduler( void )\r
1066 {\r
1067         /* Stop the scheduler interrupts and call the portable scheduler end\r
1068         routine so the original ISRs can be restored if necessary.  The port\r
1069         layer must ensure interrupts enable     bit is left in the correct state. */\r
1070         portDISABLE_INTERRUPTS();\r
1071         xSchedulerRunning = pdFALSE;\r
1072         vPortEndScheduler();\r
1073 }\r
1074 /*----------------------------------------------------------*/\r
1075 \r
1076 void vTaskSuspendAll( void )\r
1077 {\r
1078         portENTER_CRITICAL();\r
1079                 ++uxSchedulerSuspended;\r
1080         portEXIT_CRITICAL();\r
1081 }\r
1082 /*----------------------------------------------------------*/\r
1083 \r
1084 signed portBASE_TYPE xTaskResumeAll( void )\r
1085 {\r
1086 register tskTCB *pxTCB;\r
1087 signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
1088 \r
1089         /* It is possible that an ISR caused a task to be removed from an event\r
1090         list while the scheduler was suspended.  If this was the case then the\r
1091         removed task will have been added to the xPendingReadyList.  Once the\r
1092         scheduler has been resumed it is safe to move all the pending ready\r
1093         tasks from this list into their appropriate ready list. */\r
1094         portENTER_CRITICAL();\r
1095         {\r
1096                 --uxSchedulerSuspended;\r
1097 \r
1098                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1099                 {                       \r
1100                         if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )\r
1101                         {\r
1102                                 portBASE_TYPE xYieldRequired = pdFALSE;\r
1103                                 \r
1104                                 /* Move any readied tasks from the pending list into the\r
1105                                 appropriate ready list. */\r
1106                                 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY(  ( ( xList * ) &xPendingReadyList ) ) ) != NULL )\r
1107                                 {\r
1108                                         vListRemove( &( pxTCB->xEventListItem ) );\r
1109                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1110                                         prvAddTaskToReadyQueue( pxTCB );\r
1111                                         \r
1112                                         /* If we have moved a task that has a priority higher than\r
1113                                         the current task then we should yield. */\r
1114                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1115                                         {\r
1116                                                 xYieldRequired = pdTRUE;\r
1117                                         }\r
1118                                 }\r
1119 \r
1120                                 /* If any ticks occurred while the scheduler was suspended then\r
1121                                 they should be processed now.  This ensures the tick count does not\r
1122                                 slip, and that any delayed tasks are resumed at the correct time. */\r
1123                                 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1124                                 {\r
1125                                         while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1126                                         {\r
1127                                                 vTaskIncrementTick();\r
1128                                                 --uxMissedTicks;\r
1129                                         }\r
1130 \r
1131                                         /* As we have processed some ticks it is appropriate to yield\r
1132                                         to ensure the highest priority task that is ready to run is\r
1133                                         the task actually running. */\r
1134                                         xYieldRequired = pdTRUE;\r
1135                                 }\r
1136                                 \r
1137                                 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )\r
1138                                 {\r
1139                                         xAlreadyYielded = pdTRUE;\r
1140                                         xMissedYield = pdFALSE;\r
1141                                         taskYIELD();\r
1142                                 }\r
1143                         }\r
1144                 }\r
1145         }\r
1146         portEXIT_CRITICAL();\r
1147 \r
1148         return xAlreadyYielded;\r
1149 }\r
1150 \r
1151 \r
1152 \r
1153 \r
1154 \r
1155 \r
1156 /*-----------------------------------------------------------\r
1157  * PUBLIC TASK UTILITIES documented in task.h\r
1158  *----------------------------------------------------------*/\r
1159 \r
1160 \r
1161 \r
1162 portTickType xTaskGetTickCount( void )\r
1163 {\r
1164 portTickType xTicks;\r
1165 \r
1166         /* Critical section required if running on a 16 bit processor. */\r
1167         taskENTER_CRITICAL();\r
1168         {\r
1169                 xTicks = xTickCount;\r
1170         }\r
1171         taskEXIT_CRITICAL();\r
1172 \r
1173         return xTicks;\r
1174 }\r
1175 /*-----------------------------------------------------------*/\r
1176 \r
1177 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )\r
1178 {\r
1179 unsigned portBASE_TYPE uxNumberOfTasks;\r
1180 \r
1181         taskENTER_CRITICAL();\r
1182                 uxNumberOfTasks = uxCurrentNumberOfTasks;\r
1183         taskEXIT_CRITICAL();\r
1184 \r
1185         return uxNumberOfTasks;\r
1186 }\r
1187 /*-----------------------------------------------------------*/\r
1188 \r
1189 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1190 \r
1191         void vTaskList( signed portCHAR *pcWriteBuffer )\r
1192         {\r
1193         unsigned portBASE_TYPE uxQueue;\r
1194 \r
1195                 /* This is a VERY costly function that should be used for debug only.\r
1196                 It leaves interrupts disabled for a LONG time. */\r
1197 \r
1198         vTaskSuspendAll();\r
1199                 {\r
1200                         /* Run through all the lists that could potentially contain a TCB and\r
1201                         report the task name, state and stack high water mark. */\r
1202 \r
1203                         pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;\r
1204                         strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );\r
1205 \r
1206                         uxQueue = uxTopUsedPriority + 1;\r
1207 \r
1208                         do\r
1209                         {\r
1210                                 uxQueue--;\r
1211 \r
1212                                 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )\r
1213                                 {\r
1214                                         prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );                     \r
1215                                 }\r
1216                         }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1217 \r
1218                         if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )\r
1219                         {\r
1220                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );\r
1221                         }\r
1222 \r
1223                         if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )\r
1224                         {\r
1225                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );\r
1226                         }\r
1227 \r
1228                         if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )\r
1229                         {\r
1230                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );\r
1231                         }\r
1232 \r
1233                         if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1234                         {\r
1235                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );\r
1236                         }\r
1237                 }\r
1238         xTaskResumeAll();\r
1239         }\r
1240 \r
1241 #endif\r
1242 /*----------------------------------------------------------*/\r
1243 \r
1244 #if ( configUSE_TRACE_FACILITY == 1 )\r
1245 \r
1246         void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )\r
1247         {\r
1248                 portENTER_CRITICAL();\r
1249                 {\r
1250                         pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;\r
1251                         pcTraceBufferStart = pcBuffer;\r
1252                         pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );\r
1253                         xTracing = pdTRUE;\r
1254                 }\r
1255                 portEXIT_CRITICAL();\r
1256         }\r
1257 \r
1258 #endif\r
1259 /*----------------------------------------------------------*/\r
1260 \r
1261 #if ( configUSE_TRACE_FACILITY == 1 )\r
1262 \r
1263         unsigned portLONG ulTaskEndTrace( void )\r
1264         {\r
1265         unsigned portLONG ulBufferLength;\r
1266 \r
1267                 portENTER_CRITICAL();\r
1268                         xTracing = pdFALSE;\r
1269                 portEXIT_CRITICAL();\r
1270 \r
1271                 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );\r
1272 \r
1273                 return ulBufferLength;\r
1274         }\r
1275 \r
1276 #endif\r
1277 \r
1278 \r
1279 \r
1280 /*-----------------------------------------------------------\r
1281  * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES\r
1282  * documented in task.h\r
1283  *----------------------------------------------------------*/\r
1284 \r
1285 \r
1286 inline void vTaskIncrementTick( void )\r
1287 {\r
1288         /* Called by the portable layer each time a tick interrupt occurs.\r
1289         Increments the tick then checks to see if the new tick value will cause any\r
1290         tasks to be unblocked. */\r
1291         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1292         {\r
1293                 ++xTickCount;\r
1294                 if( xTickCount == ( portTickType ) 0 )\r
1295                 {\r
1296                         xList *pxTemp;\r
1297 \r
1298                         /* Tick count has overflowed so we need to swap the delay lists.  \r
1299                         If there are any items in pxDelayedTaskList here then there is \r
1300                         an error! */\r
1301                         pxTemp = pxDelayedTaskList;\r
1302                         pxDelayedTaskList = pxOverflowDelayedTaskList;\r
1303                         pxOverflowDelayedTaskList = pxTemp;\r
1304             xNumOfOverflows++;\r
1305                 }\r
1306 \r
1307                 /* See if this tick has made a timeout expire. */\r
1308                 prvCheckDelayedTasks();\r
1309         }\r
1310         else\r
1311         {\r
1312                 ++uxMissedTicks;\r
1313 \r
1314                 /* The tick hook gets called at regular intervals, even if the \r
1315                 scheduler is locked. */\r
1316                 #if ( configUSE_TICK_HOOK == 1 )\r
1317                 {\r
1318                         extern void vApplicationTickHook( void );\r
1319 \r
1320                         vApplicationTickHook();\r
1321                 }\r
1322                 #endif\r
1323         }\r
1324 \r
1325         #if ( configUSE_TICK_HOOK == 1 )\r
1326         {\r
1327                 extern void vApplicationTickHook( void );\r
1328 \r
1329                 /* Guard against the tick hook being called when the missed tick\r
1330                 count is being unwound (when the scheduler is being unlocked. */\r
1331                 if( uxMissedTicks == 0 )\r
1332                 {\r
1333                         vApplicationTickHook();\r
1334                 }\r
1335         }\r
1336         #endif\r
1337 }\r
1338 /*-----------------------------------------------------------*/\r
1339 \r
1340 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1341 \r
1342         void vTaskCleanUpResources( void )\r
1343         {\r
1344         unsigned portSHORT usQueue;\r
1345         volatile tskTCB *pxTCB;\r
1346 \r
1347                 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;\r
1348 \r
1349                 /* Remove any TCB's from the ready queues. */\r
1350                 do\r
1351                 {\r
1352                         usQueue--;\r
1353 \r
1354                         while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )\r
1355                         {\r
1356                                 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );\r
1357                                 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1358 \r
1359                                 prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1360                         }\r
1361                 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1362 \r
1363                 /* Remove any TCB's from the delayed queue. */\r
1364                 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )\r
1365                 {\r
1366                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );\r
1367                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1368 \r
1369                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1370                 }\r
1371 \r
1372                 /* Remove any TCB's from the overflow delayed queue. */\r
1373                 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )\r
1374                 {\r
1375                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );\r
1376                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1377 \r
1378                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1379                 }\r
1380 \r
1381                 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1382                 {\r
1383                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );\r
1384                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1385 \r
1386                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1387                 }               \r
1388 \r
1389                 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )\r
1390                 {\r
1391                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );\r
1392                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1393 \r
1394                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1395                 }               \r
1396         }\r
1397 \r
1398 #endif\r
1399 /*-----------------------------------------------------------*/\r
1400 \r
1401 void vTaskSwitchContext( void )\r
1402 {\r
1403         if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )\r
1404         {\r
1405                 /* The scheduler is currently suspended - do not allow a context\r
1406                 switch. */\r
1407                 xMissedYield = pdTRUE;\r
1408                 return;\r
1409         }\r
1410 \r
1411         /* Find the highest priority queue that contains ready tasks. */\r
1412         while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )\r
1413         {\r
1414                 --uxTopReadyPriority;\r
1415         }\r
1416 \r
1417         /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the\r
1418         same priority get an equal share of the processor time. */\r
1419         listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );\r
1420         vWriteTraceToBuffer();\r
1421 }\r
1422 /*-----------------------------------------------------------*/\r
1423 \r
1424 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )\r
1425 {\r
1426 portTickType xTimeToWake;\r
1427 \r
1428         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1429         SCHEDULER SUSPENDED. */\r
1430 \r
1431         /* Place the event list item of the TCB in the appropriate event list.\r
1432         This is placed in the list in priority order so the highest priority task\r
1433         is the first to be woken by the event. */\r
1434         vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );\r
1435 \r
1436         /* We must remove ourselves from the ready list before adding ourselves\r
1437         to the blocked list as the same list item is used for both lists.  We have\r
1438         exclusive access to the ready lists as the scheduler is locked. */\r
1439         vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1440 \r
1441 \r
1442         #if ( INCLUDE_vTaskSuspend == 1 )\r
1443         {                        \r
1444                 if( xTicksToWait == portMAX_DELAY )\r
1445                 {\r
1446                         /* Add ourselves to the suspended task list instead of a delayed task\r
1447                         list to ensure we are not woken by a timing event.  We will block\r
1448                         indefinitely. */\r
1449                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1450                 }\r
1451                 else\r
1452                 {\r
1453                         /* Calculate the time at which the task should be woken if the event does\r
1454                         not occur.  This may overflow but this doesn't matter. */\r
1455                         xTimeToWake = xTickCount + xTicksToWait;\r
1456                 \r
1457                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1458                 \r
1459                         if( xTimeToWake < xTickCount )\r
1460                         {\r
1461                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1462                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1463                         }\r
1464                         else\r
1465                         {\r
1466                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1467                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1468                         }\r
1469                 }\r
1470         }\r
1471         #else\r
1472         {\r
1473                         /* Calculate the time at which the task should be woken if the event does\r
1474                         not occur.  This may overflow but this doesn't matter. */\r
1475                         xTimeToWake = xTickCount + xTicksToWait;\r
1476                 \r
1477                         listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1478                 \r
1479                         if( xTimeToWake < xTickCount )\r
1480                         {\r
1481                                 /* Wake time has overflowed.  Place this item in the overflow list. */\r
1482                                 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1483                         }\r
1484                         else\r
1485                         {\r
1486                                 /* The wake time has not overflowed, so we can use the current block list. */\r
1487                                 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1488                         }\r
1489         }\r
1490         #endif\r
1491 }\r
1492 /*-----------------------------------------------------------*/\r
1493 \r
1494 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )\r
1495 {\r
1496 tskTCB *pxUnblockedTCB;\r
1497 portBASE_TYPE xReturn;\r
1498 \r
1499         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1500         SCHEDULER SUSPENDED.  It can also be called from within an ISR. */\r
1501 \r
1502         /* The event list is sorted in priority order, so we can remove the\r
1503         first in the list, remove the TCB from the delayed list, and add\r
1504         it to the ready list.\r
1505         \r
1506         If an event is for a queue that is locked then this function will never\r
1507         get called - the lock count on the queue will get modified instead.  This\r
1508         means we can always expect exclusive access to the event list here. */\r
1509         pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );\r
1510         vListRemove( &( pxUnblockedTCB->xEventListItem ) );\r
1511 \r
1512         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1513         {\r
1514                 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );\r
1515                 prvAddTaskToReadyQueue( pxUnblockedTCB );\r
1516         }\r
1517         else\r
1518         {\r
1519                 /* We cannot access the delayed or ready lists, so will hold this\r
1520                 task pending until the scheduler is resumed. */\r
1521                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );\r
1522         }\r
1523 \r
1524         if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1525         {\r
1526                 /* Return true if the task removed from the event list has\r
1527                 a higher priority than the calling task.  This allows\r
1528                 the calling task to know if it should force a context\r
1529                 switch now. */\r
1530                 xReturn = pdTRUE;\r
1531         }\r
1532         else\r
1533         {\r
1534                 xReturn = pdFALSE;\r
1535         }\r
1536 \r
1537         return xReturn;\r
1538 }\r
1539 /*-----------------------------------------------------------*/\r
1540 \r
1541 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )\r
1542 {\r
1543     pxTimeOut->xOverflowCount = xNumOfOverflows;\r
1544     pxTimeOut->xTimeOnEntering = xTickCount;\r
1545 }\r
1546 /*-----------------------------------------------------------*/\r
1547 \r
1548 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType *pxTicksToWait )\r
1549 {\r
1550 portBASE_TYPE xReturn;\r
1551 \r
1552     if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount >= pxTimeOut->xTimeOnEntering ) )\r
1553     {\r
1554         /* The tick count is greater than the time at which vTaskSetTimeout() \r
1555                 was called, but has also overflowed since vTaskSetTimeOut() was called.\r
1556         It must have wrapped all the way around and gone past us again. This\r
1557         passed since vTaskSetTimeout() was called. */\r
1558         xReturn = pdTRUE;\r
1559     }\r
1560     else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )\r
1561     {\r
1562         /* Not a genuine timeout. Adjust parameters for time remaining. */\r
1563         *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );\r
1564         vTaskSetTimeOutState( pxTimeOut );\r
1565         xReturn = pdFALSE;\r
1566     }\r
1567     else\r
1568     {\r
1569         xReturn = pdTRUE;\r
1570     }\r
1571 \r
1572     return xReturn;\r
1573 }\r
1574 /*-----------------------------------------------------------*/\r
1575 \r
1576 void vTaskMissedYield( void )\r
1577 {\r
1578         xMissedYield = pdTRUE;\r
1579 }\r
1580 \r
1581 /*\r
1582  * -----------------------------------------------------------\r
1583  * The Idle task.\r
1584  * ----------------------------------------------------------\r
1585  *\r
1586  * The portTASK_FUNCTION() macro is used to allow port/compiler specific\r
1587  * language extensions.  The equivalent prototype for this function is:\r
1588  *\r
1589  * void prvIdleTask( void *pvParameters );\r
1590  *\r
1591  */\r
1592 static portTASK_FUNCTION( prvIdleTask, pvParameters )\r
1593 {\r
1594         /* Stop warnings. */\r
1595         ( void ) pvParameters;\r
1596 \r
1597         for( ;; )\r
1598         {\r
1599                 /* See if any tasks have been deleted. */\r
1600                 prvCheckTasksWaitingTermination();\r
1601 \r
1602                 #if ( configUSE_PREEMPTION == 0 )\r
1603                 {\r
1604                         /* If we are not using preemption we keep forcing a task switch to\r
1605                         see if any other task has become available.  If we are using\r
1606                         preemption we don't need to do this as any task becoming available\r
1607                         will automatically get the processor anyway. */\r
1608                         taskYIELD();    \r
1609                 }\r
1610                 #endif\r
1611 \r
1612                 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )\r
1613                 {\r
1614                         /* When using preemption tasks of equal priority will be\r
1615                         timesliced.  If a task that is sharing the idle priority is ready\r
1616                         to run then the idle task should yield before the end of the\r
1617                         timeslice.\r
1618                         \r
1619                         A critical region is not required here as we are just reading from\r
1620                         the list, and an occasional incorrect value will not matter.  If\r
1621                         the ready list at the idle priority contains more than one task\r
1622                         then a task other than the idle task is ready to execute. */\r
1623                         if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )\r
1624                         {\r
1625                                 taskYIELD();\r
1626                         }\r
1627                 }\r
1628                 #endif\r
1629 \r
1630                 #if ( configUSE_IDLE_HOOK == 1 )\r
1631                 {\r
1632                         extern void vApplicationIdleHook( void );\r
1633 \r
1634                         /* Call the user defined function from within the idle task.  This\r
1635                         allows the application designer to add background functionality\r
1636                         without the overhead of a separate task.\r
1637                         NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,\r
1638                         CALL A FUNCTION THAT MIGHT BLOCK. */\r
1639                         vApplicationIdleHook();\r
1640                 }\r
1641                 #endif\r
1642         }\r
1643 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */\r
1644 \r
1645 \r
1646 \r
1647 \r
1648 \r
1649 \r
1650 \r
1651 /*-----------------------------------------------------------\r
1652  * File private functions documented at the top of the file.\r
1653  *----------------------------------------------------------*/\r
1654 \r
1655 \r
1656 \r
1657 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )\r
1658 {\r
1659         pxTCB->usStackDepth = usStackDepth;\r
1660 \r
1661         /* Store the function name in the TCB. */\r
1662         strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );\r
1663         pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';\r
1664 \r
1665         /* This is used as an array index so must ensure it's not too large. */\r
1666         if( uxPriority >= configMAX_PRIORITIES )\r
1667         {\r
1668                 uxPriority = configMAX_PRIORITIES - 1;\r
1669         }\r
1670 \r
1671         pxTCB->uxPriority = uxPriority;\r
1672 \r
1673         vListInitialiseItem( &( pxTCB->xGenericListItem ) );\r
1674         vListInitialiseItem( &( pxTCB->xEventListItem ) );\r
1675 \r
1676         /* Set the pxTCB as a link back from the xListItem.  This is so we can get\r
1677         back to the containing TCB from a generic item in a list. */\r
1678         listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );\r
1679 \r
1680         /* Event lists are always in priority order. */\r
1681         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );\r
1682         listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );\r
1683 }\r
1684 /*-----------------------------------------------------------*/\r
1685 \r
1686 static void prvInitialiseTaskLists( void )\r
1687 {\r
1688 unsigned portBASE_TYPE uxPriority;\r
1689 \r
1690         for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )\r
1691         {\r
1692                 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );\r
1693         }\r
1694 \r
1695         vListInitialise( ( xList * ) &xDelayedTaskList1 );\r
1696         vListInitialise( ( xList * ) &xDelayedTaskList2 );\r
1697         vListInitialise( ( xList * ) &xPendingReadyList );\r
1698 \r
1699         #if ( INCLUDE_vTaskDelete == 1 )\r
1700         {\r
1701                 vListInitialise( ( xList * ) &xTasksWaitingTermination );\r
1702         }\r
1703         #endif\r
1704 \r
1705         #if ( INCLUDE_vTaskSuspend == 1 )\r
1706         {\r
1707                 vListInitialise( ( xList * ) &xSuspendedTaskList );\r
1708         }\r
1709         #endif\r
1710 \r
1711         /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList\r
1712         using list2. */\r
1713         pxDelayedTaskList = &xDelayedTaskList1;\r
1714         pxOverflowDelayedTaskList = &xDelayedTaskList2;\r
1715 }\r
1716 /*-----------------------------------------------------------*/\r
1717 \r
1718 static void prvCheckTasksWaitingTermination( void )\r
1719 {                                                       \r
1720         #if ( INCLUDE_vTaskDelete == 1 )\r
1721         {                               \r
1722                 portBASE_TYPE xListIsEmpty;\r
1723 \r
1724                 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called\r
1725                 too often in the idle task. */\r
1726                 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )\r
1727                 {\r
1728                         vTaskSuspendAll();\r
1729                                 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );                          \r
1730                         xTaskResumeAll();\r
1731 \r
1732                         if( !xListIsEmpty )\r
1733                         {\r
1734                                 tskTCB *pxTCB;\r
1735 \r
1736                                 portENTER_CRITICAL();\r
1737                                 {                       \r
1738                                         pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );\r
1739                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1740                                         --uxCurrentNumberOfTasks;\r
1741                                         --uxTasksDeleted;\r
1742                                 }\r
1743                                 portEXIT_CRITICAL();\r
1744 \r
1745                                 prvDeleteTCB( pxTCB );\r
1746                         }\r
1747                 }\r
1748         }\r
1749         #endif\r
1750 }\r
1751 /*-----------------------------------------------------------*/\r
1752 \r
1753 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )\r
1754 {\r
1755 tskTCB *pxNewTCB;\r
1756 \r
1757         /* Allocate space for the TCB.  Where the memory comes from depends on\r
1758         the implementation of the port malloc function. */\r
1759         pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );\r
1760 \r
1761         if( pxNewTCB != NULL )\r
1762         {\r
1763                 /* Allocate space for the stack used by the task being created.\r
1764                 The base of the stack memory stored in the TCB so the task can\r
1765                 be deleted later if required. */\r
1766                 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );\r
1767 \r
1768                 if( pxNewTCB->pxStack == NULL )\r
1769                 {\r
1770                         /* Could not allocate the stack.  Delete the allocated TCB. */\r
1771                         vPortFree( pxNewTCB );                  \r
1772                         pxNewTCB = NULL;                        \r
1773                 }               \r
1774                 else\r
1775                 {\r
1776                         /* Just to help debugging. */\r
1777                         memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );\r
1778                 }\r
1779         }\r
1780 \r
1781         return pxNewTCB;\r
1782 }\r
1783 /*-----------------------------------------------------------*/\r
1784 \r
1785 #if ( configUSE_TRACE_FACILITY == 1 )\r
1786 \r
1787         static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )\r
1788         {\r
1789         volatile tskTCB *pxNextTCB, *pxFirstTCB;\r
1790         static portCHAR pcStatusString[ 50 ];\r
1791         unsigned portSHORT usStackRemaining;\r
1792 \r
1793                 /* Write the details of all the TCB's in pxList into the buffer. */\r
1794                 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );\r
1795                 do\r
1796                 {\r
1797                         listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );\r
1798                         usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );\r
1799                         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
1800                         strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );\r
1801 \r
1802                 } while( pxNextTCB != pxFirstTCB );\r
1803         }\r
1804 \r
1805 #endif\r
1806 /*-----------------------------------------------------------*/\r
1807 \r
1808 #if ( configUSE_TRACE_FACILITY == 1 )\r
1809         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )\r
1810         {\r
1811         register unsigned portSHORT usCount = 0;\r
1812 \r
1813                 while( *pucStackByte == tskSTACK_FILL_BYTE )\r
1814                 {\r
1815                         pucStackByte -= portSTACK_GROWTH;\r
1816                         usCount++;\r
1817                 }\r
1818 \r
1819                 usCount /= sizeof( portSTACK_TYPE );\r
1820 \r
1821                 return usCount;\r
1822         }\r
1823 #endif\r
1824 /*-----------------------------------------------------------*/\r
1825 \r
1826 \r
1827 \r
1828 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
1829 \r
1830         static void prvDeleteTCB( tskTCB *pxTCB )\r
1831         {\r
1832                 /* Free up the memory allocated by the scheduler for the task.  It is up to\r
1833                 the task to free any memory allocated at the application level. */\r
1834                 vPortFree( pxTCB->pxStack );\r
1835                 vPortFree( pxTCB );\r
1836         }\r
1837 \r
1838 #endif\r
1839 \r
1840 \r
1841 /*-----------------------------------------------------------*/\r
1842 \r
1843 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )\r
1844 \r
1845         xTaskHandle xTaskGetCurrentTaskHandle( void )\r
1846         {\r
1847         xTaskHandle xReturn;\r
1848 \r
1849                 portENTER_CRITICAL();\r
1850                 {\r
1851                         xReturn = ( xTaskHandle ) pxCurrentTCB;\r
1852                 }\r
1853                 portEXIT_CRITICAL();\r
1854 \r
1855                 return xReturn;\r
1856         }\r
1857 \r
1858 #endif\r
1859 \r
1860 \r
1861 \r
1862 \r
1863 \r