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

   1 /*\r
   2         FreeRTOS.org V4.1.2 - Copyright (C) 2003-2006 Richard Barry.\r
   3 \r
   4         This file is part of the FreeRTOS.org distribution.\r
   5 \r
   6         FreeRTOS.org is free software; you can redistribute it and/or modify\r
   7         it under the terms of the GNU General Public License as published by\r
   8         the Free Software Foundation; either version 2 of the License, or\r
   9         (at your option) any later version.\r
  10 \r
  11         FreeRTOS.org is distributed in the hope that it will be useful,\r
  12         but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14         GNU General Public License for more details.\r
  15 \r
  16         You should have received a copy of the GNU General Public License\r
  17         along with FreeRTOS.org; if not, write to the Free Software\r
  18         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\r
  19 \r
  20         A special exception to the GPL can be applied should you wish to distribute\r
  21         a combined work that includes FreeRTOS.org, without being obliged to provide\r
  22         the source code for any proprietary components.  See the licensing section\r
  23         of http://www.FreeRTOS.org for full details of how and when the exception\r
  24         can be applied.\r
  25 \r
  26         ***************************************************************************\r
  27         See http://www.FreeRTOS.org for documentation, latest information, license\r
  28         and contact details.  Please ensure to read the configuration and relevant\r
  29         port sections of the online documentation.\r
  30         ***************************************************************************\r
  31 */\r
  32 \r
  33 /*\r
  34 Changes from V1.00:\r
  35         \r
  36         + Call to portRESTORE_CONTEXT has been removed.  The first context\r
  37           switch is now performed within sPortStartScheduler().\r
  38 \r
  39 Changes from V1.01:\r
  40 \r
  41         + More use of 8bit data types.\r
  42         + Function name prefixes changed where the data type returned has changed.\r
  43         + configUSE_TRACE_FACILITY is no longer defined by default.\r
  44 \r
  45 Changes from V1.2.0\r
  46 \r
  47         + Introduced ucTopReadyPriority.  This tracks the highest priority ready\r
  48           queue that contains a valid TCB and thus makes the context switch\r
  49           slightly faster.\r
  50 \r
  51         + prvAddTaskToReadyQueue() has been made a macro.\r
  52 \r
  53 Changes from V1.2.6\r
  54 \r
  55         + Added conditional compilation directives.\r
  56         + Extended API.\r
  57         + Rearranged function order.\r
  58         + Creating a task now causes a context switch if the task being created\r
  59           has a higher priority than the calling task - assuming the kernel is\r
  60           running.\r
  61         + vTaskDelete() now only causes a context switch if the calling task is\r
  62           the task being deleted.\r
  63 \r
  64 Changes from V2.0.0\r
  65 \r
  66         + Allow the type of the tick count to be 16 or 32 bits.\r
  67         + Introduce xPendingReadyList feature to allow the time interrupts have to\r
  68           be disabled to be minimised.\r
  69         + Remove the #if( INCLUDE_vTaskSuspendAll ) statements.  vTaskSuspendAll()\r
  70           is now always included as it is used by the scheduler itself.\r
  71 \r
  72 Changes from V2.1.0\r
  73 \r
  74         + Bug fix - pxCurrentTCB is now initialised before the call to\r
  75           prvInitializeTaskLists().  Previously pxCurrentTCB could be accessed\r
  76           while null.\r
  77 \r
  78 Changed from V2.1.1\r
  79 \r
  80         + Change to where lStackSize is declared within sTaskCreate() to prevent\r
  81           compiler warnings with 8051 port.\r
  82 \r
  83 Changes from V2.2.0\r
  84 \r
  85         + Explicit use of 'signed' qualifier on portCHAR types added.\r
  86         + Changed odd calculation of initial pxTopOfStack value when\r
  87           portSTACK_GROWTH < 0.\r
  88         + Removed pcVersionNumber definition.\r
  89 \r
  90 Changes from V2.5.3\r
  91 \r
  92         + cTaskResumeAll() modified to ensure it can be called prior to the task\r
  93           lists being initialised.\r
  94 \r
  95 Changes from V2.5.5\r
  96 \r
  97         + Added API function vTaskDelayUntil().\r
  98         + Added INCLUDE_vTaskDelay conditional compilation.\r
  99 \r
 100 Changes from V2.6.0\r
 101 \r
 102         + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it\r
 103           can be used on ARM architectures.\r
 104         + tskMAX_TASK_NAME_LEN definition replaced with the port specific\r
 105           configMAX_TASK_NAME_LEN definition.\r
 106         + Removed the call to strcpy when copying across the task name into the\r
 107           TCB.\r
 108         + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called\r
 109           too often in the idle task.\r
 110 \r
 111 Changes between V3.0.0 and V2.6.1\r
 112 \r
 113         + When resuming the scheduler a yield is performed if either a tick has\r
 114           been missed, or a task is moved from the pending ready list into a ready\r
 115           list.  Previously a yield was not performed on this second condition.\r
 116         + Introduced the type portBASE_TYPE.  This necessitates several API\r
 117           changes.\r
 118         + Removed the sUsingPreemption variable.  The constant defined in\r
 119           portmacro.h is now used directly.\r
 120         + The idle task can now include an optional hook function - and no longer\r
 121           completes its time slice if other tasks with equal priority to it are\r
 122           ready to run.\r
 123         + See the FreeRTOS.org documentation for more information on V2.x.x to\r
 124           V3.x.x modifications.\r
 125 \r
 126 Changes from V3.1.1\r
 127 \r
 128         + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to\r
 129           be called while the scheduler is suspended.\r
 130         + Corrected the task ordering within event lists.\r
 131 \r
 132 Changes from V3.2.0\r
 133 \r
 134         + Added function xTaskGetCurrentTaskHandle().\r
 135 \r
 136 Changes from V3.2.4\r
 137 \r
 138         + Changed the volatile declarations on some variables to reflect the \r
 139           changes to the list definitions.\r
 140         + Changed the order of the TCB definition so there is commonality between\r
 141           the task control block and a co-routine control block.\r
 142         + Allow the scheduler to be started even if no tasks other than the idle\r
 143           task has been created.  This allows co-routines to run even when no tasks\r
 144           have been created.\r
 145         + The need for a context switch is now signalled if a task woken by an \r
 146           event has a priority greater or equal to the currently running task.\r
 147           Previously this was only greater than.\r
 148 \r
 149 Changes from V4.0.0\r
 150 \r
 151         + Added the xMissedYield handling.\r
 152 \r
 153 Changes from V4.0.1\r
 154 \r
 155         + The function vTaskList() now suspends the scheduler rather than disabling\r
 156           interrupts during the creation of the task list.  \r
 157         + Allow a task to delete itself by passing in its own handle.  Previously \r
 158           this could only be done by passing in NULL.\r
 159         + The tick hook function is now called only within a tick isr.  Previously\r
 160           it was also called when the tick function was called during the scheduler\r
 161           unlocking process.\r
 162 \r
 163 Changes from V4.0.3\r
 164 \r
 165         + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary\r
 166           yields.\r
 167 \r
 168 Changed from V4.0.4\r
 169 \r
 170         + Bug fix:  The 'value' of the event list item is updated when the priority\r
 171           of a task is changed.  Previously only the priority of the TCB itself was\r
 172           changed.\r
 173         + When resuming a task a check is first made to see if the task is actually\r
 174           suspended.\r
 175         + vTaskPrioritySet() and vTaskResume() no longer use the event list item.\r
 176           This has not been necessary since V4.0.1 when the xMissedYield handling\r
 177           was added.\r
 178         + Implement xTaskResumeFromISR().\r
 179 \r
 180 Changes from V4.0.5\r
 181 \r
 182         + Added utility functions and xOverflowCount variable to facilitate the\r
 183           queue.c changes.\r
 184 \r
 185 Changes from V4.1.2\r
 186         \r
 187         + Tasks that block with a timeout of portMAX_DELAY are now blocked \r
 188           indefinitely.  Previously portMAX_DELAY was just the longest block time\r
 189           possible.\r
 190 */\r
 191 \r
 192 #include <stdio.h>\r
 193 #include <stdlib.h>\r
 194 #include <string.h>\r
 195 \r
 196 #include "FreeRTOS.h"\r
 197 #include "task.h"\r
 198 \r
 199 /*\r
 200  * Macro to define the amount of stack available to the idle task.\r
 201  */\r
 202 #define tskIDLE_STACK_SIZE      configMINIMAL_STACK_SIZE\r
 203 \r
 204 \r
 205 /*\r
 206  * Default a definitions for backwards compatibility with old\r
 207  * portmacro.h files.\r
 208  */\r
 209 #ifndef configMAX_TASK_NAME_LEN\r
 210         #define configMAX_TASK_NAME_LEN 16\r
 211 #endif\r
 212 \r
 213 #ifndef INCLUDE_xTaskGetCurrentTaskHandle\r
 214         #define INCLUDE_xTaskGetCurrentTaskHandle 0\r
 215 #endif\r
 216 \r
 217 #ifndef configIDLE_SHOULD_YIELD\r
 218         #define configIDLE_SHOULD_YIELD         1\r
 219 #endif\r
 220 \r
 221 #if configMAX_TASK_NAME_LEN < 1\r
 222         #undef configMAX_TASK_NAME_LEN\r
 223         #define configMAX_TASK_NAME_LEN 1\r
 224 #endif\r
 225 \r
 226 #ifndef INCLUDE_xTaskResumeFromISR\r
 227         #define INCLUDE_xTaskResumeFromISR 1\r
 228 #endif \r
 229 \r
 230 /*\r
 231  * Task control block.  A task control block (TCB) is allocated to each task,\r
 232  * and stores the context of the task.\r
 233  */\r
 234 typedef struct tskTaskControlBlock\r
 235 {\r
 236         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
 237         xListItem                               xGenericListItem;       /*< List item used to place the TCB in ready and blocked queues. */\r
 238         xListItem                               xEventListItem;         /*< List item used to place the TCB in event lists. */\r
 239         unsigned portBASE_TYPE  uxPriority;                     /*< The priority of the task where 0 is the lowest priority. */\r
 240         portSTACK_TYPE                  *pxStack;                       /*< Points to the start of the stack. */\r
 241         unsigned portBASE_TYPE  uxTCBNumber;            /*< This is used for tracing the scheduler and making debugging easier only. */\r
 242         signed portCHAR                 pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */\r
 243         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
 244 } tskTCB;\r
 245 \r
 246 /*lint -e956 */\r
 247 \r
 248 tskTCB * volatile pxCurrentTCB = NULL;                                  \r
 249 \r
 250 /* Lists for ready and blocked tasks. --------------------*/\r
 251 \r
 252 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */\r
 253 static xList xDelayedTaskList1;                                                 /*< Delayed tasks. */\r
 254 static xList xDelayedTaskList2;                                                 /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */\r
 255 static xList * volatile pxDelayedTaskList;                              /*< Points to the delayed task list currently being used. */\r
 256 static xList * volatile pxOverflowDelayedTaskList;              /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */\r
 257 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
 258 \r
 259 #if ( INCLUDE_vTaskDelete == 1 )\r
 260 \r
 261         static volatile xList xTasksWaitingTermination;         /*< Tasks that have been deleted - but the their memory not yet freed. */\r
 262         static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;\r
 263 \r
 264 #endif\r
 265 \r
 266 #if ( INCLUDE_vTaskSuspend == 1 )\r
 267 \r
 268         static xList xSuspendedTaskList;                                        /*< Tasks that are currently suspended. */\r
 269 \r
 270 #endif\r
 271 \r
 272 /* File private variables. --------------------------------*/\r
 273 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks   = ( unsigned portBASE_TYPE ) 0;\r
 274 static volatile portTickType xTickCount                                                 = ( portTickType ) 0;\r
 275 static unsigned portBASE_TYPE uxTopUsedPriority                                 = tskIDLE_PRIORITY;\r
 276 static volatile unsigned portBASE_TYPE uxTopReadyPriority               = tskIDLE_PRIORITY;\r
 277 static volatile signed portBASE_TYPE xSchedulerRunning                  = pdFALSE;\r
 278 static volatile unsigned portBASE_TYPE uxSchedulerSuspended             = ( unsigned portBASE_TYPE ) pdFALSE;\r
 279 static volatile unsigned portBASE_TYPE uxMissedTicks                    = ( unsigned portBASE_TYPE ) 0;\r
 280 static volatile portBASE_TYPE xMissedYield                                              = ( portBASE_TYPE ) pdFALSE;\r
 281 static volatile portBASE_TYPE xNumOfOverflows                                   = ( portBASE_TYPE ) 0;\r
 282 /* Debugging and trace facilities private variables and macros. ------------*/\r
 283 \r
 284 /*\r
 285  * The value used to fill the stack of a task when the task is created.  This\r
 286  * is used purely for checking the high water mark for tasks.\r
 287  */\r
 288 #define tskSTACK_FILL_BYTE      ( 0xa5 )\r
 289 \r
 290 /*\r
 291  * Macros used by vListTask to indicate which state a task is in.\r
 292  */\r
 293 #define tskBLOCKED_CHAR         ( ( signed portCHAR ) 'B' )\r
 294 #define tskREADY_CHAR           ( ( signed portCHAR ) 'R' )\r
 295 #define tskDELETED_CHAR         ( ( signed portCHAR ) 'D' )\r
 296 #define tskSUSPENDED_CHAR       ( ( signed portCHAR ) 'S' )\r
 297 \r
 298 /*\r
 299  * Macros and private variables used by the trace facility.\r
 300  */\r
 301 #if ( configUSE_TRACE_FACILITY == 1 )\r
 302 \r
 303         #define tskSIZE_OF_EACH_TRACE_LINE                      ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )\r
 304         static volatile signed portCHAR * volatile pcTraceBuffer;\r
 305         static signed portCHAR *pcTraceBufferStart;\r
 306         static signed portCHAR *pcTraceBufferEnd;\r
 307         static signed portBASE_TYPE xTracing = pdFALSE;\r
 308 \r
 309 #endif\r
 310 \r
 311 /*\r
 312  * Macro that writes a trace of scheduler activity to a buffer.  This trace\r
 313  * shows which task is running when and is very useful as a debugging tool.\r
 314  * As this macro is called each context switch it is a good idea to undefine\r
 315  * it if not using the facility.\r
 316  */\r
 317 #if ( configUSE_TRACE_FACILITY == 1 )\r
 318 \r
 319         #define vWriteTraceToBuffer()                                                                                                                                   \\r
 320         {                                                                                                                                                                                               \\r
 321                 if( xTracing )                                                                                                                                                          \\r
 322                 {                                                                                                                                                                                       \\r
 323                         static unsigned portBASE_TYPE uxPreviousTask = 255;                                                                             \\r
 324                                                                                                                                                                                                         \\r
 325                         if( uxPreviousTask != pxCurrentTCB->uxTCBNumber )                                                                               \\r
 326                         {                                                                                                                                                                               \\r
 327                                 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd )                         \\r
 328                                 {                                                                                                                                                                       \\r
 329                                         uxPreviousTask = pxCurrentTCB->uxTCBNumber;                                                                             \\r
 330                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount;              \\r
 331                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 332                                         *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask;  \\r
 333                                         pcTraceBuffer += sizeof( unsigned portLONG );                                                                   \\r
 334                                 }                                                                                                                                                                       \\r
 335                                 else                                                                                                                                                            \\r
 336                                 {                                                                                                                                                                       \\r
 337                                         xTracing = pdFALSE;                                                                                                                             \\r
 338                                 }                                                                                                                                                                       \\r
 339                         }                                                                                                                                                                               \\r
 340                 }                                                                                                                                                                                       \\r
 341         }\r
 342 \r
 343 #else\r
 344 \r
 345         #define vWriteTraceToBuffer()\r
 346 \r
 347 #endif\r
 348 \r
 349 \r
 350 /*\r
 351  * Place the task represented by pxTCB into the appropriate ready queue for\r
 352  * the task.  It is inserted at the end of the list.  One quirk of this is\r
 353  * that if the task being inserted is at the same priority as the currently\r
 354  * executing task, then it will only be rescheduled after the currently\r
 355  * executing task has been rescheduled.\r
 356  */\r
 357 #define prvAddTaskToReadyQueue( pxTCB )                                                                                                                                                 \\r
 358 {                                                                                                                                                                                                                               \\r
 359         if( pxTCB->uxPriority > uxTopReadyPriority )                                                                                                                            \\r
 360         {                                                                                                                                                                                                                       \\r
 361                 uxTopReadyPriority = pxTCB->uxPriority;                                                                                                                                 \\r
 362         }                                                                                                                                                                                                                       \\r
 363         vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) );        \\r
 364 }               \r
 365 \r
 366 /*\r
 367  * Macro that looks at the list of tasks that are currently delayed to see if\r
 368  * any require waking.\r
 369  *\r
 370  * Tasks are stored in the queue in the order of their wake time - meaning\r
 371  * once one tasks has been found whose timer has not expired we need not look\r
 372  * any further down the list.\r
 373  */\r
 374 #define prvCheckDelayedTasks()                                                                                                                                                                          \\r
 375 {                                                                                                                                                                                                                                       \\r
 376 register tskTCB *pxTCB;                                                                                                                                                                                         \\r
 377                                                                                                                                                                                                                                         \\r
 378         while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL )                                              \\r
 379         {                                                                                                                                                                                                                               \\r
 380                 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) )                                                                      \\r
 381                 {                                                                                                                                                                                                                       \\r
 382                         break;                                                                                                                                                                                                  \\r
 383                 }                                                                                                                                                                                                                       \\r
 384                 vListRemove( &( pxTCB->xGenericListItem ) );                                                                                                                            \\r
 385                 /* Is the task waiting on an event also? */                                                                                                                                     \\r
 386                 if( pxTCB->xEventListItem.pvContainer )                                                                                                                                         \\r
 387                 {                                                                                                                                                                                                                       \\r
 388                         vListRemove( &( pxTCB->xEventListItem ) );                                                                                                                              \\r
 389                 }                                                                                                                                                                                                                       \\r
 390                 prvAddTaskToReadyQueue( pxTCB );                                                                                                                \\r
 391         }                                                                                                                                                                                                                               \\r
 392 }                                                                                                                                                                                       \r
 393 \r
 394 /*\r
 395  * Several functions take an xTaskHandle parameter that can optionally be NULL,\r
 396  * where NULL is used to indicate that the handle of the currently executing\r
 397  * task should be used in place of the parameter.  This macro simply checks to\r
 398  * see if the parameter is NULL and returns a pointer to the appropriate TCB.\r
 399  */\r
 400 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )\r
 401 \r
 402 \r
 403 /* File private functions. --------------------------------*/\r
 404 \r
 405 /*\r
 406  * Utility to ready a TCB for a given task.  Mainly just copies the parameters\r
 407  * into the TCB structure.\r
 408  */\r
 409 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );\r
 410 \r
 411 /*\r
 412  * Utility to ready all the lists used by the scheduler.  This is called\r
 413  * automatically upon the creation of the first task.\r
 414  */\r
 415 static void prvInitialiseTaskLists( void );\r
 416 \r
 417 /*\r
 418  * The idle task, which as all tasks is implemented as a never ending loop.\r
 419  * The idle task is automatically created and added to the ready lists upon\r
 420  * creation of the first user task.\r
 421  *\r
 422  * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific\r
 423  * language extensions.  The equivalent prototype for this function is:\r
 424  *\r
 425  * void prvIdleTask( void *pvParameters );\r
 426  *\r
 427  */\r
 428 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );\r
 429 \r
 430 /*\r
 431  * Utility to free all memory allocated by the scheduler to hold a TCB,\r
 432  * including the stack pointed to by the TCB.\r
 433  *\r
 434  * This does not free memory allocated by the task itself (i.e. memory\r
 435  * allocated by calls to pvPortMalloc from within the tasks application code).\r
 436  */\r
 437 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
 438         static void prvDeleteTCB( tskTCB *pxTCB );\r
 439 #endif\r
 440 \r
 441 /*\r
 442  * Used only by the idle task.  This checks to see if anything has been placed\r
 443  * in the list of tasks waiting to be deleted.  If so the task is cleaned up\r
 444  * and its TCB deleted.\r
 445  */\r
 446 static void prvCheckTasksWaitingTermination( void );\r
 447 \r
 448 /*\r
 449  * Allocates memory from the heap for a TCB and associated stack.  Checks the\r
 450  * allocation was successful.\r
 451  */\r
 452 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );\r
 453 \r
 454 /*\r
 455  * Called from vTaskList.  vListTasks details all the tasks currently under\r
 456  * control of the scheduler.  The tasks may be in one of a number of lists.\r
 457  * prvListTaskWithinSingleList accepts a list and details the tasks from\r
 458  * within just that list.\r
 459  *\r
 460  * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM\r
 461  * NORMAL APPLICATION CODE.\r
 462  */\r
 463 #if ( configUSE_TRACE_FACILITY == 1 )\r
 464 \r
 465         static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );\r
 466 \r
 467 #endif\r
 468 \r
 469 /*\r
 470  * When a task is created, the stack of the task is filled with a known value.\r
 471  * This function determines the 'high water mark' of the task stack by\r
 472  * determining how much of the stack remains at the original preset value.\r
 473  */\r
 474 #if ( configUSE_TRACE_FACILITY == 1 )\r
 475 \r
 476         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );\r
 477 \r
 478 #endif\r
 479 \r
 480 /*lint +e956 */\r
 481 \r
 482 \r
 483 \r
 484 \r
 485 \r
 486 /*-----------------------------------------------------------\r
 487  * TASK CREATION API documented in task.h\r
 488  *----------------------------------------------------------*/\r
 489 \r
 490 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )\r
 491 {\r
 492 signed portBASE_TYPE xReturn;\r
 493 tskTCB * pxNewTCB;\r
 494 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */\r
 495 \r
 496         /* Allocate the memory required by the TCB and stack for the new task.\r
 497         checking that the allocation was successful. */\r
 498         pxNewTCB = prvAllocateTCBAndStack( usStackDepth );\r
 499 \r
 500         if( pxNewTCB != NULL )\r
 501         {               \r
 502                 portSTACK_TYPE *pxTopOfStack;\r
 503 \r
 504                 /* Setup the newly allocated TCB with the initial state of the task. */\r
 505                 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );\r
 506 \r
 507                 /* Calculate the top of stack address.  This depends on whether the\r
 508                 stack grows from high memory to low (as per the 80x86) or visa versa.\r
 509                 portSTACK_GROWTH is used to make the result positive or negative as\r
 510                 required by the port. */\r
 511                 #if portSTACK_GROWTH < 0\r
 512                 {\r
 513                         pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );\r
 514                 }\r
 515                 #else\r
 516                 {\r
 517                         pxTopOfStack = pxNewTCB->pxStack;       \r
 518                 }\r
 519                 #endif\r
 520 \r
 521                 /* Initialize the TCB stack to look as if the task was already running,\r
 522                 but had been interrupted by the scheduler.  The return address is set\r
 523                 to the start of the task function. Once the stack has been initialised\r
 524                 the     top of stack variable is updated. */\r
 525                 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );\r
 526 \r
 527                 /* We are going to manipulate the task queues to add this task to a\r
 528                 ready list, so must make sure no interrupts occur. */\r
 529                 portENTER_CRITICAL();\r
 530                 {\r
 531                         uxCurrentNumberOfTasks++;\r
 532                         if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )\r
 533                         {\r
 534                                 /* As this is the first task it must also be the current task. */\r
 535                                 pxCurrentTCB =  pxNewTCB;\r
 536 \r
 537                                 /* This is the first task to be created so do the preliminary\r
 538                                 initialisation required.  We will not recover if this call\r
 539                                 fails, but we will report the failure. */\r
 540                                 prvInitialiseTaskLists();\r
 541                         }\r
 542                         else\r
 543                         {       \r
 544                                 /* If the scheduler is not already running, make this task the\r
 545                                 current task if it is the highest priority task to be created\r
 546                                 so far. */\r
 547                                 if( xSchedulerRunning == pdFALSE )\r
 548                                 {\r
 549                                         if( pxCurrentTCB->uxPriority <= uxPriority )\r
 550                                         {\r
 551                                                 pxCurrentTCB = pxNewTCB;        \r
 552                                         }\r
 553                                 }\r
 554                         }                               \r
 555 \r
 556                         /* Remember the top priority to make context switching faster.  Use\r
 557                         the priority in pxNewTCB as this has been capped to a valid value. */\r
 558                         if( pxNewTCB->uxPriority > uxTopUsedPriority )\r
 559                         {\r
 560                                 uxTopUsedPriority = pxNewTCB->uxPriority;\r
 561                         }\r
 562 \r
 563                         /* Add a counter into the TCB for tracing only. */\r
 564                         pxNewTCB->uxTCBNumber = uxTaskNumber;\r
 565                         uxTaskNumber++;\r
 566 \r
 567                         prvAddTaskToReadyQueue( pxNewTCB );\r
 568 \r
 569                         xReturn = pdPASS;\r
 570                 }\r
 571                 portEXIT_CRITICAL();\r
 572         }\r
 573         else\r
 574         {\r
 575                 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;\r
 576         }\r
 577 \r
 578         if( xReturn == pdPASS )\r
 579         {\r
 580                 if( ( void * ) pxCreatedTask != NULL )\r
 581                 {\r
 582                         /* Pass the TCB out - in an anonymous way.  The calling function/\r
 583                         task can use this as a handle to delete the task later if\r
 584                         required.*/\r
 585                         *pxCreatedTask = ( xTaskHandle ) pxNewTCB;\r
 586                 }\r
 587 \r
 588                 if( xSchedulerRunning != pdFALSE )\r
 589                 {\r
 590                         /* If the created task is of a higher priority than the current task\r
 591                         then it should run now. */\r
 592                         if( pxCurrentTCB->uxPriority < uxPriority )\r
 593                         {\r
 594                                 taskYIELD();\r
 595                         }\r
 596                 }\r
 597         }\r
 598 \r
 599         return xReturn;\r
 600 }\r
 601 /*-----------------------------------------------------------*/\r
 602 \r
 603 #if ( INCLUDE_vTaskDelete == 1 )\r
 604 \r
 605         void vTaskDelete( xTaskHandle pxTaskToDelete )\r
 606         {\r
 607         tskTCB *pxTCB;\r
 608 \r
 609                 taskENTER_CRITICAL();\r
 610                 {\r
 611                         /* Ensure a yield is performed if the current task is being \r
 612                         deleted. */\r
 613                         if( pxTaskToDelete == pxCurrentTCB )\r
 614                         {\r
 615                                 pxTaskToDelete = NULL;\r
 616                         }\r
 617 \r
 618                         /* If null is passed in here then we are deleting ourselves. */\r
 619                         pxTCB = prvGetTCBFromHandle( pxTaskToDelete );\r
 620 \r
 621                         /* Remove task from the ready list and place in the     termination list.\r
 622                         This will stop the task from be scheduled.  The idle task will check\r
 623                         the termination list and free up any memory allocated by the\r
 624                         scheduler for the TCB and stack. */\r
 625                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 626 \r
 627                         /* Is the task waiting on an event also? */                                                                                             \r
 628                         if( pxTCB->xEventListItem.pvContainer )\r
 629                         {\r
 630                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 631                         }\r
 632 \r
 633                         vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );\r
 634 \r
 635                         /* Increment the ucTasksDeleted variable so the idle task knows\r
 636                         there is a task that has been deleted and that it should therefore\r
 637                         check the xTasksWaitingTermination list. */\r
 638                         ++uxTasksDeleted;\r
 639                 }\r
 640                 taskEXIT_CRITICAL();\r
 641 \r
 642                 /* Force a reschedule if we have just deleted the current task. */\r
 643                 if( xSchedulerRunning != pdFALSE ) \r
 644                 {\r
 645                         if( ( void * ) pxTaskToDelete == NULL )\r
 646                         {\r
 647                                 taskYIELD();\r
 648                         }\r
 649                 }\r
 650         }\r
 651 \r
 652 #endif\r
 653 \r
 654 \r
 655 \r
 656 \r
 657 \r
 658 \r
 659 /*-----------------------------------------------------------\r
 660  * TASK CONTROL API documented in task.h\r
 661  *----------------------------------------------------------*/\r
 662 \r
 663 #if ( INCLUDE_vTaskDelayUntil == 1 )\r
 664 \r
 665         void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )\r
 666         {\r
 667         portTickType xTimeToWake;\r
 668         portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;\r
 669 \r
 670                 vTaskSuspendAll();\r
 671                 {\r
 672                         /* Generate the tick time at which the task wants to wake. */\r
 673                         xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;\r
 674 \r
 675                         if( xTickCount < *pxPreviousWakeTime )\r
 676                         {\r
 677                                 /* The tick count has overflowed since this function was\r
 678                                 lasted called.  In this case the only time we should ever\r
 679                                 actually delay is if the wake time has also     overflowed,\r
 680                                 and the wake time is greater than the tick time.  When this\r
 681                                 is the case it is as if neither time had overflowed. */\r
 682                                 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )\r
 683                                 {\r
 684                                         xShouldDelay = pdTRUE;\r
 685                                 }\r
 686                         }\r
 687                         else\r
 688                         {\r
 689                                 /* The tick time has not overflowed.  In this case we will\r
 690                                 delay if either the wake time has overflowed, and/or the\r
 691                                 tick time is less than the wake time. */\r
 692                                 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )\r
 693                                 {\r
 694                                         xShouldDelay = pdTRUE;\r
 695                                 }\r
 696                         }\r
 697 \r
 698                         /* Update the wake time ready for the next call. */\r
 699                         *pxPreviousWakeTime = xTimeToWake;\r
 700 \r
 701                         if( xShouldDelay )\r
 702                         {\r
 703                                 /* We must remove ourselves from the ready list before adding\r
 704                                 ourselves to the blocked list as the same list item is used for\r
 705                                 both lists. */\r
 706                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 707 \r
 708                                 /* The list item will be inserted in wake time order. */\r
 709                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 710 \r
 711                                 if( xTimeToWake < xTickCount )\r
 712                                 {\r
 713                                         /* Wake time has overflowed.  Place this item in the\r
 714                                         overflow list. */\r
 715                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 716                                 }\r
 717                                 else\r
 718                                 {\r
 719                                         /* The wake time has not overflowed, so we can use the\r
 720                                         current block list. */\r
 721                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 722                                 }\r
 723                         }\r
 724                 }\r
 725                 xAlreadyYielded = xTaskResumeAll();\r
 726 \r
 727                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 728                 have put ourselves to sleep. */\r
 729                 if( !xAlreadyYielded )\r
 730                 {\r
 731                         taskYIELD();\r
 732                 }\r
 733         }       \r
 734         \r
 735 #endif\r
 736 /*-----------------------------------------------------------*/\r
 737 \r
 738 #if ( INCLUDE_vTaskDelay == 1 )\r
 739 \r
 740         void vTaskDelay( portTickType xTicksToDelay )\r
 741         {\r
 742         portTickType xTimeToWake;\r
 743         signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
 744 \r
 745                 /* A delay time of zero just forces a reschedule. */\r
 746                 if( xTicksToDelay > ( portTickType ) 0 )\r
 747                 {\r
 748                         vTaskSuspendAll();\r
 749                         {\r
 750                                 /* A task that is removed from the event list while the\r
 751                                 scheduler is suspended will not get placed in the ready\r
 752                                 list or removed from the blocked list until the scheduler\r
 753                                 is resumed.\r
 754                                 \r
 755                                 This task cannot be in an event list as it is the currently\r
 756                                 executing task. */\r
 757 \r
 758                                 /* Calculate the time to wake - this may overflow but this is\r
 759                                 not a problem. */\r
 760                                 xTimeToWake = xTickCount + xTicksToDelay;\r
 761 \r
 762                                 /* We must remove ourselves from the ready list before adding\r
 763                                 ourselves to the blocked list as the same list item is used for\r
 764                                 both lists. */\r
 765                                 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 766 \r
 767                                 /* The list item will be inserted in wake time order. */\r
 768                                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
 769 \r
 770                                 if( xTimeToWake < xTickCount )\r
 771                                 {\r
 772                                         /* Wake time has overflowed.  Place this item in the\r
 773                                         overflow list. */\r
 774                                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 775                                 }\r
 776                                 else\r
 777                                 {\r
 778                                         /* The wake time has not overflowed, so we can use the\r
 779                                         current block list. */\r
 780                                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
 781                                 }\r
 782                         }\r
 783                         xAlreadyYielded = xTaskResumeAll();\r
 784                 }\r
 785                 \r
 786                 /* Force a reschedule if xTaskResumeAll has not already done so, we may\r
 787                 have put ourselves to sleep. */\r
 788                 if( !xAlreadyYielded )\r
 789                 {\r
 790                         taskYIELD();\r
 791                 }\r
 792         }\r
 793         \r
 794 #endif\r
 795 /*-----------------------------------------------------------*/\r
 796 \r
 797 #if ( INCLUDE_uxTaskPriorityGet == 1 )\r
 798 \r
 799         unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )\r
 800         {\r
 801         tskTCB *pxTCB;\r
 802         unsigned portBASE_TYPE uxReturn;\r
 803 \r
 804                 taskENTER_CRITICAL();\r
 805                 {\r
 806                         /* If null is passed in here then we are changing the\r
 807                         priority of the calling function. */\r
 808                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 809                         uxReturn = pxTCB->uxPriority;\r
 810                 }\r
 811                 taskEXIT_CRITICAL();\r
 812 \r
 813                 return uxReturn;\r
 814         }\r
 815 \r
 816 #endif\r
 817 /*-----------------------------------------------------------*/\r
 818 \r
 819 #if ( INCLUDE_vTaskPrioritySet == 1 )\r
 820 \r
 821         void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )\r
 822         {\r
 823         tskTCB *pxTCB;\r
 824         unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;\r
 825 \r
 826                 /* Ensure the new priority is valid. */\r
 827                 if( uxNewPriority >= configMAX_PRIORITIES )\r
 828                 {\r
 829                         uxNewPriority = configMAX_PRIORITIES - 1;\r
 830                 }\r
 831 \r
 832                 taskENTER_CRITICAL();\r
 833                 {\r
 834                         /* If null is passed in here then we are changing the\r
 835                         priority of the calling function. */\r
 836                         pxTCB = prvGetTCBFromHandle( pxTask );\r
 837                         uxCurrentPriority = pxTCB->uxPriority;\r
 838 \r
 839                         if( uxCurrentPriority != uxNewPriority )\r
 840                         {\r
 841                                 /* The priority change may have readied a task of higher\r
 842                                 priority than the calling task. */\r
 843                                 if( uxNewPriority > pxCurrentTCB->uxPriority ) \r
 844                                 {\r
 845                                         if( pxTask != NULL )\r
 846                                         {\r
 847                                                 /* The priority of another task is being raised.  If we\r
 848                                                 were raising the priority of the currently running task\r
 849                                                 there would be no need to switch as it must have already\r
 850                                                 been the highest priority task. */\r
 851                                                 xYieldRequired = pdTRUE;\r
 852                                         }\r
 853                                 }\r
 854                                 else if( pxTask == NULL )\r
 855                                 {\r
 856                                         /* Setting our own priority down means there may now be another\r
 857                                         task of higher priority that is ready to execute. */\r
 858                                         xYieldRequired = pdTRUE;\r
 859                                 }\r
 860                         \r
 861                                 pxTCB->uxPriority = uxNewPriority;\r
 862                                 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );\r
 863 \r
 864                                 /* If the task is in the blocked or suspended list we need do\r
 865                                 nothing more than change it's priority variable. However, if\r
 866                                 the task is in a ready list it needs to be removed and placed\r
 867                                 in the queue appropriate to its new priority. */\r
 868                                 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )\r
 869                                 {\r
 870                                         /* The task is currently in its ready list - remove before adding\r
 871                                         it to it's new ready list.  As we are in a critical section we\r
 872                                         can do this even if the scheduler is suspended. */\r
 873                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 874                                         prvAddTaskToReadyQueue( pxTCB );\r
 875                                 }                       \r
 876                                 \r
 877                                 if( xYieldRequired == pdTRUE )\r
 878                                 {\r
 879                                         taskYIELD();\r
 880                                 }                               \r
 881                         }\r
 882                 }\r
 883                 taskEXIT_CRITICAL();\r
 884         }\r
 885 \r
 886 #endif\r
 887 /*-----------------------------------------------------------*/\r
 888 \r
 889 #if ( INCLUDE_vTaskSuspend == 1 )\r
 890 \r
 891         void vTaskSuspend( xTaskHandle pxTaskToSuspend )\r
 892         {\r
 893         tskTCB *pxTCB;\r
 894 \r
 895                 taskENTER_CRITICAL();\r
 896                 {\r
 897                         /* Ensure a yield is performed if the current task is being \r
 898                         suspended. */\r
 899                         if( pxTaskToSuspend == pxCurrentTCB )\r
 900                         {\r
 901                                 pxTaskToSuspend = NULL;\r
 902                         }\r
 903 \r
 904                         /* If null is passed in here then we are suspending ourselves. */\r
 905                         pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );\r
 906 \r
 907                         /* Remove task from the ready/delayed list and place in the     suspended list. */\r
 908                         vListRemove( &( pxTCB->xGenericListItem ) );\r
 909 \r
 910                         /* Is the task waiting on an event also? */                                                                                             \r
 911                         if( pxTCB->xEventListItem.pvContainer )\r
 912                         {\r
 913                                 vListRemove( &( pxTCB->xEventListItem ) );\r
 914                         }\r
 915 \r
 916                         vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );\r
 917                 }\r
 918                 taskEXIT_CRITICAL();\r
 919 \r
 920                 /* We may have just suspended the current task. */\r
 921                 if( ( void * ) pxTaskToSuspend == NULL )\r
 922                 {\r
 923                         taskYIELD();\r
 924                 }\r
 925         }\r
 926 \r
 927 #endif\r
 928 /*-----------------------------------------------------------*/\r
 929 \r
 930 #if ( INCLUDE_vTaskSuspend == 1 )\r
 931 \r
 932         void vTaskResume( xTaskHandle pxTaskToResume )\r
 933         {\r
 934         tskTCB *pxTCB;\r
 935 \r
 936                 /* Remove the task from whichever list it is currently in, and place\r
 937                 it in the ready list. */\r
 938                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
 939 \r
 940                 /* The parameter cannot be NULL as it is impossible to resume the\r
 941                 currently executing task. */\r
 942                 if( pxTCB != NULL )\r
 943                 {\r
 944                         taskENTER_CRITICAL();\r
 945                         {\r
 946                                 /* Is the task we are attempting to resume actually suspended? */\r
 947                                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
 948                                 {\r
 949                                         /* Has the task already been resumed from within an ISR? */\r
 950                                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
 951                                         {                       \r
 952                                                 /* As we are in a critical section we can access the ready \r
 953                                                 lists even if the scheduler is suspended. */\r
 954                                                 vListRemove(  &( pxTCB->xGenericListItem ) );\r
 955                                                 prvAddTaskToReadyQueue( pxTCB );\r
 956 \r
 957                                                 /* We may have just resumed a higher priority task. */\r
 958                                                 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
 959                                                 {\r
 960                                                         /* This yield may not cause the task just resumed to run, but\r
 961                                                         will leave the lists in the correct state for the next yield. */\r
 962                                                         taskYIELD();\r
 963                                                 }\r
 964                                         }\r
 965                                 }\r
 966                         }\r
 967                         taskEXIT_CRITICAL();\r
 968                 }\r
 969         }\r
 970 \r
 971 #endif\r
 972 \r
 973 /*-----------------------------------------------------------*/\r
 974 \r
 975 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
 976 \r
 977         portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )\r
 978         {\r
 979         portBASE_TYPE xYieldRequired = pdFALSE;\r
 980         tskTCB *pxTCB;\r
 981 \r
 982                 pxTCB = ( tskTCB * ) pxTaskToResume;\r
 983 \r
 984                 /* Is the task we are attempting to resume actually suspended? */\r
 985                 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )\r
 986                 {\r
 987                         /* Has the task already been resumed from within an ISR? */\r
 988                         if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )\r
 989                         {\r
 990                                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
 991                                 {\r
 992                                         xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );\r
 993                                         vListRemove(  &( pxTCB->xGenericListItem ) );   \r
 994                                         prvAddTaskToReadyQueue( pxTCB );\r
 995                                 }\r
 996                                 else\r
 997                                 {\r
 998                                         /* We cannot access the delayed or ready lists, so will hold this\r
 999                                         task pending until the scheduler is resumed, at which point a \r
1000                                         yield will be preformed if necessary. */\r
1001                                         vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );\r
1002                                 }\r
1003                         }\r
1004                 }\r
1005 \r
1006                 return xYieldRequired;\r
1007         }\r
1008 \r
1009 #endif\r
1010 \r
1011 \r
1012 \r
1013 \r
1014 /*-----------------------------------------------------------\r
1015  * PUBLIC SCHEDULER CONTROL documented in task.h\r
1016  *----------------------------------------------------------*/\r
1017 \r
1018 \r
1019 void vTaskStartScheduler( void )\r
1020 {\r
1021 portBASE_TYPE xReturn;\r
1022 \r
1023         /* Add the idle task at the lowest priority. */\r
1024         xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );\r
1025 \r
1026         if( xReturn == pdPASS )\r
1027         {\r
1028                 /* Interrupts are turned off here, to ensure a tick does not occur\r
1029                 before or during the call to xPortStartScheduler().  The stacks of\r
1030                 the created tasks contain a status word with interrupts switched on\r
1031                 so interrupts will automatically get re-enabled when the first task\r
1032                 starts to run.\r
1033                 \r
1034                 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE\r
1035                 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */\r
1036                 portDISABLE_INTERRUPTS();\r
1037 \r
1038                 xSchedulerRunning = pdTRUE;\r
1039                 xTickCount = ( portTickType ) 0;\r
1040 \r
1041                 /* Setting up the timer tick is hardware specific and thus in the\r
1042                 portable interface. */\r
1043                 if( xPortStartScheduler() )\r
1044                 {\r
1045                         /* Should not reach here as if the scheduler is running the\r
1046                         function will not return. */\r
1047                 }\r
1048                 else\r
1049                 {\r
1050                         /* Should only reach here if a task calls xTaskEndScheduler(). */\r
1051                 }\r
1052         }\r
1053 }\r
1054 /*-----------------------------------------------------------*/\r
1055 \r
1056 void vTaskEndScheduler( void )\r
1057 {\r
1058         /* Stop the scheduler interrupts and call the portable scheduler end\r
1059         routine so the original ISRs can be restored if necessary.  The port\r
1060         layer must ensure interrupts enable     bit is left in the correct state. */\r
1061         portDISABLE_INTERRUPTS();\r
1062         xSchedulerRunning = pdFALSE;\r
1063         vPortEndScheduler();\r
1064 }\r
1065 /*----------------------------------------------------------*/\r
1066 \r
1067 void vTaskSuspendAll( void )\r
1068 {\r
1069         portENTER_CRITICAL();\r
1070                 ++uxSchedulerSuspended;\r
1071         portEXIT_CRITICAL();\r
1072 }\r
1073 /*----------------------------------------------------------*/\r
1074 \r
1075 signed portBASE_TYPE xTaskResumeAll( void )\r
1076 {\r
1077 register tskTCB *pxTCB;\r
1078 signed portBASE_TYPE xAlreadyYielded = pdFALSE;\r
1079 \r
1080         /* It is possible that an ISR caused a task to be removed from an event\r
1081         list while the scheduler was suspended.  If this was the case then the\r
1082         removed task will have been added to the xPendingReadyList.  Once the\r
1083         scheduler has been resumed it is safe to move all the pending ready\r
1084         tasks from this list into their appropriate ready list. */\r
1085         portENTER_CRITICAL();\r
1086         {\r
1087                 --uxSchedulerSuspended;\r
1088 \r
1089                 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1090                 {                       \r
1091                         if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )\r
1092                         {\r
1093                                 portBASE_TYPE xYieldRequired = pdFALSE;\r
1094                                 \r
1095                                 /* Move any readied tasks from the pending list into the\r
1096                                 appropriate ready list. */\r
1097                                 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY(  ( ( xList * ) &xPendingReadyList ) ) ) != NULL )\r
1098                                 {\r
1099                                         vListRemove( &( pxTCB->xEventListItem ) );\r
1100                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1101                                         prvAddTaskToReadyQueue( pxTCB );\r
1102                                         \r
1103                                         /* If we have moved a task that has a priority higher than\r
1104                                         the current task then we should yield. */\r
1105                                         if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1106                                         {\r
1107                                                 xYieldRequired = pdTRUE;\r
1108                                         }\r
1109                                 }\r
1110 \r
1111                                 /* If any ticks occurred while the scheduler was suspended then\r
1112                                 they should be processed now.  This ensures the tick count does not\r
1113                                 slip, and that any delayed tasks are resumed at the correct time. */\r
1114                                 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1115                                 {\r
1116                                         while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )\r
1117                                         {\r
1118                                                 vTaskIncrementTick();\r
1119                                                 --uxMissedTicks;\r
1120                                         }\r
1121 \r
1122                                         /* As we have processed some ticks it is appropriate to yield\r
1123                                         to ensure the highest priority task that is ready to run is\r
1124                                         the task actually running. */\r
1125                                         xYieldRequired = pdTRUE;\r
1126                                 }\r
1127                                 \r
1128                                 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )\r
1129                                 {\r
1130                                         xAlreadyYielded = pdTRUE;\r
1131                                         xMissedYield = pdFALSE;\r
1132                                         taskYIELD();\r
1133                                 }\r
1134                         }\r
1135                 }\r
1136         }\r
1137         portEXIT_CRITICAL();\r
1138 \r
1139         return xAlreadyYielded;\r
1140 }\r
1141 \r
1142 \r
1143 \r
1144 \r
1145 \r
1146 \r
1147 /*-----------------------------------------------------------\r
1148  * PUBLIC TASK UTILITIES documented in task.h\r
1149  *----------------------------------------------------------*/\r
1150 \r
1151 \r
1152 \r
1153 portTickType xTaskGetTickCount( void )\r
1154 {\r
1155 portTickType xTicks;\r
1156 \r
1157         /* Critical section required if running on a 16 bit processor. */\r
1158         taskENTER_CRITICAL();\r
1159         {\r
1160                 xTicks = xTickCount;\r
1161         }\r
1162         taskEXIT_CRITICAL();\r
1163 \r
1164         return xTicks;\r
1165 }\r
1166 /*-----------------------------------------------------------*/\r
1167 \r
1168 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )\r
1169 {\r
1170 unsigned portBASE_TYPE uxNumberOfTasks;\r
1171 \r
1172         taskENTER_CRITICAL();\r
1173                 uxNumberOfTasks = uxCurrentNumberOfTasks;\r
1174         taskEXIT_CRITICAL();\r
1175 \r
1176         return uxNumberOfTasks;\r
1177 }\r
1178 /*-----------------------------------------------------------*/\r
1179 \r
1180 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1181 \r
1182         void vTaskList( signed portCHAR *pcWriteBuffer )\r
1183         {\r
1184         unsigned portBASE_TYPE uxQueue;\r
1185 \r
1186                 /* This is a VERY costly function that should be used for debug only.\r
1187                 It leaves interrupts disabled for a LONG time. */\r
1188 \r
1189         vTaskSuspendAll();\r
1190                 {\r
1191                         /* Run through all the lists that could potentially contain a TCB and\r
1192                         report the task name, state and stack high water mark. */\r
1193 \r
1194                         pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;\r
1195                         strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );\r
1196 \r
1197                         uxQueue = uxTopUsedPriority + 1;\r
1198 \r
1199                         do\r
1200                         {\r
1201                                 uxQueue--;\r
1202 \r
1203                                 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )\r
1204                                 {\r
1205                                         prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );                     \r
1206                                 }\r
1207                         }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1208 \r
1209                         if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )\r
1210                         {\r
1211                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );\r
1212                         }\r
1213 \r
1214                         if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )\r
1215                         {\r
1216                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );\r
1217                         }\r
1218 \r
1219                         if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )\r
1220                         {\r
1221                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );\r
1222                         }\r
1223 \r
1224                         if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1225                         {\r
1226                                 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );\r
1227                         }\r
1228                 }\r
1229         xTaskResumeAll();\r
1230         }\r
1231 \r
1232 #endif\r
1233 /*----------------------------------------------------------*/\r
1234 \r
1235 #if ( configUSE_TRACE_FACILITY == 1 )\r
1236 \r
1237         void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )\r
1238         {\r
1239                 portENTER_CRITICAL();\r
1240                 {\r
1241                         pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;\r
1242                         pcTraceBufferStart = pcBuffer;\r
1243                         pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );\r
1244                         xTracing = pdTRUE;\r
1245                 }\r
1246                 portEXIT_CRITICAL();\r
1247         }\r
1248 \r
1249 #endif\r
1250 /*----------------------------------------------------------*/\r
1251 \r
1252 #if ( configUSE_TRACE_FACILITY == 1 )\r
1253 \r
1254         unsigned portLONG ulTaskEndTrace( void )\r
1255         {\r
1256         unsigned portLONG ulBufferLength;\r
1257 \r
1258                 portENTER_CRITICAL();\r
1259                         xTracing = pdFALSE;\r
1260                 portEXIT_CRITICAL();\r
1261 \r
1262                 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );\r
1263 \r
1264                 return ulBufferLength;\r
1265         }\r
1266 \r
1267 #endif\r
1268 \r
1269 \r
1270 \r
1271 /*-----------------------------------------------------------\r
1272  * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES\r
1273  * documented in task.h\r
1274  *----------------------------------------------------------*/\r
1275 \r
1276 \r
1277 inline void vTaskIncrementTick( void )\r
1278 {\r
1279         /* Called by the portable layer each time a tick interrupt occurs.\r
1280         Increments the tick then checks to see if the new tick value will cause any\r
1281         tasks to be unblocked. */\r
1282         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1283         {\r
1284                 ++xTickCount;\r
1285                 if( xTickCount == ( portTickType ) 0 )\r
1286                 {\r
1287                         xList *pxTemp;\r
1288 \r
1289                         /* Tick count has overflowed so we need to swap the delay lists.  \r
1290                         If there are any items in pxDelayedTaskList here then there is \r
1291                         an error! */\r
1292                         pxTemp = pxDelayedTaskList;\r
1293                         pxDelayedTaskList = pxOverflowDelayedTaskList;\r
1294                         pxOverflowDelayedTaskList = pxTemp;\r
1295             xNumOfOverflows++;\r
1296                 }\r
1297 \r
1298                 /* See if this tick has made a timeout expire. */\r
1299                 prvCheckDelayedTasks();\r
1300         }\r
1301         else\r
1302         {\r
1303                 ++uxMissedTicks;\r
1304 \r
1305                 /* The tick hook gets called at regular intervals, even if the \r
1306                 scheduler is locked. */\r
1307                 #if ( configUSE_TICK_HOOK == 1 )\r
1308                 {\r
1309                         extern void vApplicationTickHook( void );\r
1310 \r
1311                         vApplicationTickHook();\r
1312                 }\r
1313                 #endif\r
1314         }\r
1315 \r
1316         #if ( configUSE_TICK_HOOK == 1 )\r
1317         {\r
1318                 extern void vApplicationTickHook( void );\r
1319 \r
1320                 /* Guard against the tick hook being called when the missed tick\r
1321                 count is being unwound (when the scheduler is being unlocked. */\r
1322                 if( uxMissedTicks == 0 )\r
1323                 {\r
1324                         vApplicationTickHook();\r
1325                 }\r
1326         }\r
1327         #endif\r
1328 }\r
1329 /*-----------------------------------------------------------*/\r
1330 \r
1331 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )\r
1332 \r
1333         void vTaskCleanUpResources( void )\r
1334         {\r
1335         unsigned portSHORT usQueue;\r
1336         volatile tskTCB *pxTCB;\r
1337 \r
1338                 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;\r
1339 \r
1340                 /* Remove any TCB's from the ready queues. */\r
1341                 do\r
1342                 {\r
1343                         usQueue--;\r
1344 \r
1345                         while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )\r
1346                         {\r
1347                                 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );\r
1348                                 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1349 \r
1350                                 prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1351                         }\r
1352                 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );\r
1353 \r
1354                 /* Remove any TCB's from the delayed queue. */\r
1355                 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )\r
1356                 {\r
1357                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );\r
1358                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1359 \r
1360                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1361                 }\r
1362 \r
1363                 /* Remove any TCB's from the overflow delayed queue. */\r
1364                 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )\r
1365                 {\r
1366                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );\r
1367                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1368 \r
1369                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1370                 }\r
1371 \r
1372                 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )\r
1373                 {\r
1374                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );\r
1375                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1376 \r
1377                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1378                 }               \r
1379 \r
1380                 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )\r
1381                 {\r
1382                         listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );\r
1383                         vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );\r
1384 \r
1385                         prvDeleteTCB( ( tskTCB * ) pxTCB );\r
1386                 }               \r
1387         }\r
1388 \r
1389 #endif\r
1390 /*-----------------------------------------------------------*/\r
1391 \r
1392 void vTaskSwitchContext( void )\r
1393 {\r
1394         if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )\r
1395         {\r
1396                 /* The scheduler is currently suspended - do not allow a context\r
1397                 switch. */\r
1398                 xMissedYield = pdTRUE;\r
1399                 return;\r
1400         }\r
1401 \r
1402         /* Find the highest priority queue that contains ready tasks. */\r
1403         while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )\r
1404         {\r
1405                 --uxTopReadyPriority;\r
1406         }\r
1407 \r
1408         /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the\r
1409         same priority get an equal share of the processor time. */\r
1410         listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );\r
1411         vWriteTraceToBuffer();\r
1412 }\r
1413 /*-----------------------------------------------------------*/\r
1414 \r
1415 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )\r
1416 {\r
1417 portTickType xTimeToWake;\r
1418 \r
1419         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1420         SCHEDULER SUSPENDED. */\r
1421 \r
1422         /* Place the event list item of the TCB in the appropriate event list.\r
1423         This is placed in the list in priority order so the highest priority task\r
1424         is the first to be woken by the event. */\r
1425         vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );\r
1426 \r
1427         /* We must remove ourselves from the ready list before adding ourselves\r
1428         to the blocked list as the same list item is used for both lists.  We have\r
1429         exclusive access to the ready lists as the scheduler is locked. */\r
1430         vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1431 \r
1432         if( xTicksToWait == portMAX_DELAY )\r
1433         {\r
1434                 /* Add ourselves to the suspended task list instead of a delayed task\r
1435                 list to ensure we are not woken by a timing event.  We will block\r
1436                 indefinitely. */\r
1437                 vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1438         }\r
1439         else\r
1440         {\r
1441                 /* Calculate the time at which the task should be woken if the event does\r
1442                 not occur.  This may overflow but this doesn't matter. */\r
1443                 xTimeToWake = xTickCount + xTicksToWait;\r
1444         \r
1445                 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );\r
1446         \r
1447                 if( xTimeToWake < xTickCount )\r
1448                 {\r
1449                         /* Wake time has overflowed.  Place this item in the overflow list. */\r
1450                         vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1451                 }\r
1452                 else\r
1453                 {\r
1454                         /* The wake time has not overflowed, so we can use the current block list. */\r
1455                         vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );\r
1456                 }\r
1457         }\r
1458 }\r
1459 /*-----------------------------------------------------------*/\r
1460 \r
1461 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )\r
1462 {\r
1463 tskTCB *pxUnblockedTCB;\r
1464 portBASE_TYPE xReturn;\r
1465 \r
1466         /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE\r
1467         SCHEDULER SUSPENDED.  It can also be called from within an ISR. */\r
1468 \r
1469         /* The event list is sorted in priority order, so we can remove the\r
1470         first in the list, remove the TCB from the delayed list, and add\r
1471         it to the ready list.\r
1472         \r
1473         If an event is for a queue that is locked then this function will never\r
1474         get called - the lock count on the queue will get modified instead.  This\r
1475         means we can always expect exclusive access to the event list here. */\r
1476         pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );\r
1477         vListRemove( &( pxUnblockedTCB->xEventListItem ) );\r
1478 \r
1479         if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )\r
1480         {\r
1481                 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );\r
1482                 prvAddTaskToReadyQueue( pxUnblockedTCB );\r
1483         }\r
1484         else\r
1485         {\r
1486                 /* We cannot access the delayed or ready lists, so will hold this\r
1487                 task pending until the scheduler is resumed. */\r
1488                 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );\r
1489         }\r
1490 \r
1491         if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )\r
1492         {\r
1493                 /* Return true if the task removed from the event list has\r
1494                 a higher priority than the calling task.  This allows\r
1495                 the calling task to know if it should force a context\r
1496                 switch now. */\r
1497                 xReturn = pdTRUE;\r
1498         }\r
1499         else\r
1500         {\r
1501                 xReturn = pdFALSE;\r
1502         }\r
1503 \r
1504         return xReturn;\r
1505 }\r
1506 /*-----------------------------------------------------------*/\r
1507 \r
1508 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )\r
1509 {\r
1510     pxTimeOut->xOverflowCount = xNumOfOverflows;\r
1511     pxTimeOut->xTimeOnEntering = xTickCount;\r
1512 }\r
1513 /*-----------------------------------------------------------*/\r
1514 \r
1515 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType *pxTicksToWait )\r
1516 {\r
1517 portBASE_TYPE xReturn;\r
1518 \r
1519     if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount > pxTimeOut->xTimeOnEntering ) )\r
1520     {\r
1521         /* The tick count is greater than the time at which vTaskSetTimeout() \r
1522                 was called, but has also overflowed since vTaskSetTimeOut() was called.\r
1523         It must have wrapped all the way around and gone past us again. This\r
1524         passed since vTaskSetTimeout() was called. */\r
1525         xReturn = pdTRUE;\r
1526     }\r
1527     else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )\r
1528     {\r
1529         /* Not a genuine timeout. Adjust parameters for time remaining. */\r
1530         *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );\r
1531         vTaskSetTimeOutState( pxTimeOut );\r
1532         xReturn = pdFALSE;\r
1533     }\r
1534     else\r
1535     {\r
1536         xReturn = pdTRUE;\r
1537     }\r
1538 \r
1539     return xReturn;\r
1540 }\r
1541 /*-----------------------------------------------------------*/\r
1542 \r
1543 void vTaskMissedYield( void )\r
1544 {\r
1545         xMissedYield = pdTRUE;\r
1546 }\r
1547 \r
1548 /*\r
1549  * -----------------------------------------------------------\r
1550  * The Idle task.\r
1551  * ----------------------------------------------------------\r
1552  *\r
1553  * The portTASK_FUNCTION() macro is used to allow port/compiler specific\r
1554  * language extensions.  The equivalent prototype for this function is:\r
1555  *\r
1556  * void prvIdleTask( void *pvParameters );\r
1557  *\r
1558  */\r
1559 static portTASK_FUNCTION( prvIdleTask, pvParameters )\r
1560 {\r
1561         /* Stop warnings. */\r
1562         ( void ) pvParameters;\r
1563 \r
1564         for( ;; )\r
1565         {\r
1566                 /* See if any tasks have been deleted. */\r
1567                 prvCheckTasksWaitingTermination();\r
1568 \r
1569                 #if ( configUSE_PREEMPTION == 0 )\r
1570                 {\r
1571                         /* If we are not using preemption we keep forcing a task switch to\r
1572                         see if any other task has become available.  If we are using\r
1573                         preemption we don't need to do this as any task becoming available\r
1574                         will automatically get the processor anyway. */\r
1575                         taskYIELD();    \r
1576                 }\r
1577                 #endif\r
1578 \r
1579                 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )\r
1580                 {\r
1581                         /* When using preemption tasks of equal priority will be\r
1582                         timesliced.  If a task that is sharing the idle priority is ready\r
1583                         to run then the idle task should yield before the end of the\r
1584                         timeslice.\r
1585                         \r
1586                         A critical region is not required here as we are just reading from\r
1587                         the list, and an occasional incorrect value will not matter.  If\r
1588                         the ready list at the idle priority contains more than one task\r
1589                         then a task other than the idle task is ready to execute. */\r
1590                         if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )\r
1591                         {\r
1592                                 taskYIELD();\r
1593                         }\r
1594                 }\r
1595                 #endif\r
1596 \r
1597                 #if ( configUSE_IDLE_HOOK == 1 )\r
1598                 {\r
1599                         extern void vApplicationIdleHook( void );\r
1600 \r
1601                         /* Call the user defined function from within the idle task.  This\r
1602                         allows the application designer to add background functionality\r
1603                         without the overhead of a separate task.\r
1604                         NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,\r
1605                         CALL A FUNCTION THAT MIGHT BLOCK. */\r
1606                         vApplicationIdleHook();\r
1607                 }\r
1608                 #endif\r
1609         }\r
1610 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */\r
1611 \r
1612 \r
1613 \r
1614 \r
1615 \r
1616 \r
1617 \r
1618 /*-----------------------------------------------------------\r
1619  * File private functions documented at the top of the file.\r
1620  *----------------------------------------------------------*/\r
1621 \r
1622 \r
1623 \r
1624 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )\r
1625 {\r
1626         pxTCB->usStackDepth = usStackDepth;\r
1627 \r
1628         /* Store the function name in the TCB. */\r
1629         strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );\r
1630         pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';\r
1631 \r
1632         /* This is used as an array index so must ensure it's not too large. */\r
1633         if( uxPriority >= configMAX_PRIORITIES )\r
1634         {\r
1635                 uxPriority = configMAX_PRIORITIES - 1;\r
1636         }\r
1637 \r
1638         pxTCB->uxPriority = uxPriority;\r
1639 \r
1640         vListInitialiseItem( &( pxTCB->xGenericListItem ) );\r
1641         vListInitialiseItem( &( pxTCB->xEventListItem ) );\r
1642 \r
1643         /* Set the pxTCB as a link back from the xListItem.  This is so we can get\r
1644         back to the containing TCB from a generic item in a list. */\r
1645         listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );\r
1646 \r
1647         /* Event lists are always in priority order. */\r
1648         listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );\r
1649         listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );\r
1650 }\r
1651 /*-----------------------------------------------------------*/\r
1652 \r
1653 static void prvInitialiseTaskLists( void )\r
1654 {\r
1655 unsigned portBASE_TYPE uxPriority;\r
1656 \r
1657         for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )\r
1658         {\r
1659                 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );\r
1660         }\r
1661 \r
1662         vListInitialise( ( xList * ) &xDelayedTaskList1 );\r
1663         vListInitialise( ( xList * ) &xDelayedTaskList2 );\r
1664         vListInitialise( ( xList * ) &xPendingReadyList );\r
1665 \r
1666         #if ( INCLUDE_vTaskDelete == 1 )\r
1667         {\r
1668                 vListInitialise( ( xList * ) &xTasksWaitingTermination );\r
1669         }\r
1670         #endif\r
1671 \r
1672         #if ( INCLUDE_vTaskSuspend == 1 )\r
1673         {\r
1674                 vListInitialise( ( xList * ) &xSuspendedTaskList );\r
1675         }\r
1676         #endif\r
1677 \r
1678         /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList\r
1679         using list2. */\r
1680         pxDelayedTaskList = &xDelayedTaskList1;\r
1681         pxOverflowDelayedTaskList = &xDelayedTaskList2;\r
1682 }\r
1683 /*-----------------------------------------------------------*/\r
1684 \r
1685 static void prvCheckTasksWaitingTermination( void )\r
1686 {                                                       \r
1687         #if ( INCLUDE_vTaskDelete == 1 )\r
1688         {                               \r
1689                 portBASE_TYPE xListIsEmpty;\r
1690 \r
1691                 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called\r
1692                 too often in the idle task. */\r
1693                 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )\r
1694                 {\r
1695                         vTaskSuspendAll();\r
1696                                 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );                          \r
1697                         xTaskResumeAll();\r
1698 \r
1699                         if( !xListIsEmpty )\r
1700                         {\r
1701                                 tskTCB *pxTCB;\r
1702 \r
1703                                 portENTER_CRITICAL();\r
1704                                 {                       \r
1705                                         pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );\r
1706                                         vListRemove( &( pxTCB->xGenericListItem ) );\r
1707                                         --uxCurrentNumberOfTasks;\r
1708                                         --uxTasksDeleted;\r
1709                                 }\r
1710                                 portEXIT_CRITICAL();\r
1711 \r
1712                                 prvDeleteTCB( pxTCB );\r
1713                         }\r
1714                 }\r
1715         }\r
1716         #endif\r
1717 }\r
1718 /*-----------------------------------------------------------*/\r
1719 \r
1720 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )\r
1721 {\r
1722 tskTCB *pxNewTCB;\r
1723 \r
1724         /* Allocate space for the TCB.  Where the memory comes from depends on\r
1725         the implementation of the port malloc function. */\r
1726         pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );\r
1727 \r
1728         if( pxNewTCB != NULL )\r
1729         {\r
1730                 /* Allocate space for the stack used by the task being created.\r
1731                 The base of the stack memory stored in the TCB so the task can\r
1732                 be deleted later if required. */\r
1733                 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );\r
1734 \r
1735                 if( pxNewTCB->pxStack == NULL )\r
1736                 {\r
1737                         /* Could not allocate the stack.  Delete the allocated TCB. */\r
1738                         vPortFree( pxNewTCB );                  \r
1739                         pxNewTCB = NULL;                        \r
1740                 }               \r
1741                 else\r
1742                 {\r
1743                         /* Just to help debugging. */\r
1744                         memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );\r
1745                 }\r
1746         }\r
1747 \r
1748         return pxNewTCB;\r
1749 }\r
1750 /*-----------------------------------------------------------*/\r
1751 \r
1752 #if ( configUSE_TRACE_FACILITY == 1 )\r
1753 \r
1754         static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )\r
1755         {\r
1756         volatile tskTCB *pxNextTCB, *pxFirstTCB;\r
1757         static portCHAR pcStatusString[ 50 ];\r
1758         unsigned portSHORT usStackRemaining;\r
1759 \r
1760                 /* Write the details of all the TCB's in pxList into the buffer. */\r
1761                 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );\r
1762                 do\r
1763                 {\r
1764                         listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );\r
1765                         usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );\r
1766                         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
1767                         strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );\r
1768 \r
1769                 } while( pxNextTCB != pxFirstTCB );\r
1770         }\r
1771 \r
1772 #endif\r
1773 /*-----------------------------------------------------------*/\r
1774 \r
1775 #if ( configUSE_TRACE_FACILITY == 1 )\r
1776         unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )\r
1777         {\r
1778         register unsigned portSHORT usCount = 0;\r
1779 \r
1780                 while( *pucStackByte == tskSTACK_FILL_BYTE )\r
1781                 {\r
1782                         pucStackByte -= portSTACK_GROWTH;\r
1783                         usCount++;\r
1784                 }\r
1785 \r
1786                 usCount /= sizeof( portSTACK_TYPE );\r
1787 \r
1788                 return usCount;\r
1789         }\r
1790 #endif\r
1791 /*-----------------------------------------------------------*/\r
1792 \r
1793 \r
1794 \r
1795 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )\r
1796 \r
1797         static void prvDeleteTCB( tskTCB *pxTCB )\r
1798         {\r
1799                 /* Free up the memory allocated by the scheduler for the task.  It is up to\r
1800                 the task to free any memory allocated at the application level. */\r
1801                 vPortFree( pxTCB->pxStack );\r
1802                 vPortFree( pxTCB );\r
1803         }\r
1804 \r
1805 #endif\r
1806 \r
1807 \r
1808 /*-----------------------------------------------------------*/\r
1809 \r
1810 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )\r
1811 \r
1812         xTaskHandle xTaskGetCurrentTaskHandle( void )\r
1813         {\r
1814         xTaskHandle xReturn;\r
1815 \r
1816                 portENTER_CRITICAL();\r
1817                 {\r
1818                         xReturn = ( xTaskHandle ) pxCurrentTCB;\r
1819                 }\r
1820                 portEXIT_CRITICAL();\r
1821 \r
1822                 return xReturn;\r
1823         }\r
1824 \r
1825 #endif\r
1826 \r
1827 \r
1828 \r
1829 \r
1830 \r