2 FreeRTOS.org V4.0.5 - Copyright (C) 2003-2006 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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36 + Call to portRESTORE_CONTEXT has been removed. The first context
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37 switch is now performed within sPortStartScheduler().
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41 + More use of 8bit data types.
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42 + Function name prefixes changed where the data type returned has changed.
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43 + configUSE_TRACE_FACILITY is no longer defined by default.
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47 + Introduced ucTopReadyPriority. This tracks the highest priority ready
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48 queue that contains a valid TCB and thus makes the context switch
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51 + prvAddTaskToReadyQueue() has been made a macro.
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55 + Added conditional compilation directives.
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57 + Rearranged function order.
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58 + Creating a task now causes a context switch if the task being created
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59 has a higher priority than the calling task - assuming the kernel is
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61 + vTaskDelete() now only causes a context switch if the calling task is
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62 the task being deleted.
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66 + Allow the type of the tick count to be 16 or 32 bits.
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67 + Introduce xPendingReadyList feature to allow the time interrupts have to
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68 be disabled to be minimised.
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69 + Remove the #if( INCLUDE_vTaskSuspendAll ) statements. vTaskSuspendAll()
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70 is now always included as it is used by the scheduler itself.
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74 + Bug fix - pxCurrentTCB is now initialised before the call to
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75 prvInitializeTaskLists(). Previously pxCurrentTCB could be accessed
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80 + Change to where lStackSize is declared within sTaskCreate() to prevent
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81 compiler warnings with 8051 port.
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85 + Explicit use of 'signed' qualifier on portCHAR types added.
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86 + Changed odd calculation of initial pxTopOfStack value when
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87 portSTACK_GROWTH < 0.
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88 + Removed pcVersionNumber definition.
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92 + cTaskResumeAll() modified to ensure it can be called prior to the task
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93 lists being initialised.
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97 + Added API function vTaskDelayUntil().
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98 + Added INCLUDE_vTaskDelay conditional compilation.
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100 Changes from V2.6.0
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102 + Updated the vWriteTraceToBuffer macro to always be 4 byte aligned so it
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103 can be used on ARM architectures.
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104 + tskMAX_TASK_NAME_LEN definition replaced with the port specific
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105 configMAX_TASK_NAME_LEN definition.
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106 + Removed the call to strcpy when copying across the task name into the
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108 + Added ucTasksDeleted variable to prevent vTaskSuspendAll() being called
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109 too often in the idle task.
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111 Changes between V3.0.0 and V2.6.1
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113 + When resuming the scheduler a yield is performed if either a tick has
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114 been missed, or a task is moved from the pending ready list into a ready
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115 list. Previously a yield was not performed on this second condition.
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116 + Introduced the type portBASE_TYPE. This necessitates several API
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118 + Removed the sUsingPreemption variable. The constant defined in
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119 portmacro.h is now used directly.
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120 + The idle task can now include an optional hook function - and no longer
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121 completes its time slice if other tasks with equal priority to it are
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123 + See the FreeRTOS.org documentation for more information on V2.x.x to
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124 V3.x.x modifications.
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126 Changes from V3.1.1
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128 + Modified vTaskPrioritySet() and vTaskResume() to allow these functions to
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129 be called while the scheduler is suspended.
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130 + Corrected the task ordering within event lists.
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132 Changes from V3.2.0
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134 + Added function xTaskGetCurrentTaskHandle().
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136 Changes from V3.2.4
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138 + Changed the volatile declarations on some variables to reflect the
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139 changes to the list definitions.
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140 + Changed the order of the TCB definition so there is commonality between
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141 the task control block and a co-routine control block.
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142 + Allow the scheduler to be started even if no tasks other than the idle
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143 task has been created. This allows co-routines to run even when no tasks
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145 + The need for a context switch is now signalled if a task woken by an
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146 event has a priority greater or equal to the currently running task.
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147 Previously this was only greater than.
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149 Changes from V4.0.0
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151 + Added the xMissedYield handling.
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153 Changes from V4.0.1
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155 + The function vTaskList() now suspends the scheduler rather than disabling
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156 interrupts during the creation of the task list.
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157 + Allow a task to delete itself by passing in its own handle. Previously
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158 this could only be done by passing in NULL.
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159 + The tick hook function is now called only within a tick isr. Previously
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160 it was also called when the tick function was called during the scheduler
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163 Changes from V4.0.3
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165 + Extra checks have been placed in vTaskPrioritySet() to avoid unnecessary
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168 Changed from V4.0.4
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170 + Bug fix: The 'value' of the event list item is updated when the priority
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171 of a task is changed. Previously only the priority of the TCB itself was
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173 + When resuming a task a check is first made to see if the task is actually
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175 + vTaskPrioritySet() and vTaskResume() no longer use the event list item.
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176 This has not been necessary since V4.0.1 when the xMissedYield handling
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178 + Implement xTaskResumeFromISR().
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180 Changes from V4.0.5
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182 + Added utility functions and xOverflowCount variable to facilitate the
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187 #include <stdlib.h>
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188 #include <string.h>
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190 #include "FreeRTOS.h"
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194 * Macro to define the amount of stack available to the idle task.
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196 #define tskIDLE_STACK_SIZE configMINIMAL_STACK_SIZE
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200 * Default a definitions for backwards compatibility with old
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201 * portmacro.h files.
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203 #ifndef configMAX_TASK_NAME_LEN
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204 #define configMAX_TASK_NAME_LEN 16
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207 #ifndef INCLUDE_xTaskGetCurrentTaskHandle
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208 #define INCLUDE_xTaskGetCurrentTaskHandle 0
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211 #ifndef configIDLE_SHOULD_YIELD
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212 #define configIDLE_SHOULD_YIELD 1
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215 #if configMAX_TASK_NAME_LEN < 1
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216 #undef configMAX_TASK_NAME_LEN
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217 #define configMAX_TASK_NAME_LEN 1
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220 #ifndef INCLUDE_xTaskResumeFromISR
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221 #define INCLUDE_xTaskResumeFromISR 1
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225 * Task control block. A task control block (TCB) is allocated to each task,
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226 * and stores the context of the task.
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228 typedef struct tskTaskControlBlock
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230 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. */
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231 xListItem xGenericListItem; /*< List item used to place the TCB in ready and blocked queues. */
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232 xListItem xEventListItem; /*< List item used to place the TCB in event lists. */
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233 unsigned portBASE_TYPE uxPriority; /*< The priority of the task where 0 is the lowest priority. */
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234 portSTACK_TYPE *pxStack; /*< Points to the start of the stack. */
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235 unsigned portBASE_TYPE uxTCBNumber; /*< This is used for tracing the scheduler and making debugging easier only. */
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236 signed portCHAR pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created. Facilitates debugging only. */
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237 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. */
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242 tskTCB * volatile pxCurrentTCB = NULL;
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244 /* Lists for ready and blocked tasks. --------------------*/
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246 static xList pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
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247 static xList xDelayedTaskList1; /*< Delayed tasks. */
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248 static xList xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
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249 static xList * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
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250 static xList * volatile pxOverflowDelayedTaskList; /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */
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251 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. */
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253 #if ( INCLUDE_vTaskDelete == 1 )
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255 static volatile xList xTasksWaitingTermination; /*< Tasks that have been deleted - but the their memory not yet freed. */
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256 static volatile unsigned portBASE_TYPE uxTasksDeleted = ( unsigned portBASE_TYPE ) 0;
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260 #if ( INCLUDE_vTaskSuspend == 1 )
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262 static xList xSuspendedTaskList; /*< Tasks that are currently suspended. */
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266 /* File private variables. --------------------------------*/
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267 static volatile unsigned portBASE_TYPE uxCurrentNumberOfTasks = ( unsigned portBASE_TYPE ) 0;
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268 static volatile portTickType xTickCount = ( portTickType ) 0;
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269 static unsigned portBASE_TYPE uxTopUsedPriority = tskIDLE_PRIORITY;
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270 static volatile unsigned portBASE_TYPE uxTopReadyPriority = tskIDLE_PRIORITY;
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271 static volatile signed portBASE_TYPE xSchedulerRunning = pdFALSE;
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272 static volatile unsigned portBASE_TYPE uxSchedulerSuspended = ( unsigned portBASE_TYPE ) pdFALSE;
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273 static volatile unsigned portBASE_TYPE uxMissedTicks = ( unsigned portBASE_TYPE ) 0;
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274 static volatile portBASE_TYPE xMissedYield = ( portBASE_TYPE ) pdFALSE;
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275 static volatile portBASE_TYPE xNumOfOverflows = ( portBASE_TYPE ) 0;
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276 /* Debugging and trace facilities private variables and macros. ------------*/
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279 * The value used to fill the stack of a task when the task is created. This
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280 * is used purely for checking the high water mark for tasks.
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282 #define tskSTACK_FILL_BYTE ( 0xa5 )
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285 * Macros used by vListTask to indicate which state a task is in.
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287 #define tskBLOCKED_CHAR ( ( signed portCHAR ) 'B' )
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288 #define tskREADY_CHAR ( ( signed portCHAR ) 'R' )
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289 #define tskDELETED_CHAR ( ( signed portCHAR ) 'D' )
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290 #define tskSUSPENDED_CHAR ( ( signed portCHAR ) 'S' )
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293 * Macros and private variables used by the trace facility.
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295 #if ( configUSE_TRACE_FACILITY == 1 )
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297 #define tskSIZE_OF_EACH_TRACE_LINE ( ( unsigned portLONG ) ( sizeof( unsigned portLONG ) + sizeof( unsigned portLONG ) ) )
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298 static volatile signed portCHAR * volatile pcTraceBuffer;
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299 static signed portCHAR *pcTraceBufferStart;
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300 static signed portCHAR *pcTraceBufferEnd;
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301 static signed portBASE_TYPE xTracing = pdFALSE;
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306 * Macro that writes a trace of scheduler activity to a buffer. This trace
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307 * shows which task is running when and is very useful as a debugging tool.
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308 * As this macro is called each context switch it is a good idea to undefine
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309 * it if not using the facility.
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311 #if ( configUSE_TRACE_FACILITY == 1 )
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313 #define vWriteTraceToBuffer() \
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317 static unsigned portBASE_TYPE uxPreviousTask = 255; \
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319 if( uxPreviousTask != pxCurrentTCB->uxTCBNumber ) \
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321 if( ( pcTraceBuffer + tskSIZE_OF_EACH_TRACE_LINE ) < pcTraceBufferEnd ) \
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323 uxPreviousTask = pxCurrentTCB->uxTCBNumber; \
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324 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) xTickCount; \
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325 pcTraceBuffer += sizeof( unsigned portLONG ); \
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326 *( unsigned portLONG * ) pcTraceBuffer = ( unsigned portLONG ) uxPreviousTask; \
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327 pcTraceBuffer += sizeof( unsigned portLONG ); \
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331 xTracing = pdFALSE; \
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339 #define vWriteTraceToBuffer()
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345 * Place the task represented by pxTCB into the appropriate ready queue for
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346 * the task. It is inserted at the end of the list. One quirk of this is
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347 * that if the task being inserted is at the same priority as the currently
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348 * executing task, then it will only be rescheduled after the currently
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349 * executing task has been rescheduled.
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351 #define prvAddTaskToReadyQueue( pxTCB ) \
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353 if( pxTCB->uxPriority > uxTopReadyPriority ) \
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355 uxTopReadyPriority = pxTCB->uxPriority; \
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357 vListInsertEnd( ( xList * ) &( pxReadyTasksLists[ pxTCB->uxPriority ] ), &( pxTCB->xGenericListItem ) ); \
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361 * Macro that looks at the list of tasks that are currently delayed to see if
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362 * any require waking.
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364 * Tasks are stored in the queue in the order of their wake time - meaning
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365 * once one tasks has been found whose timer has not expired we need not look
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366 * any further down the list.
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368 #define prvCheckDelayedTasks() \
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370 register tskTCB *pxTCB; \
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372 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxDelayedTaskList ) ) != NULL ) \
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374 if( xTickCount < listGET_LIST_ITEM_VALUE( &( pxTCB->xGenericListItem ) ) ) \
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378 vListRemove( &( pxTCB->xGenericListItem ) ); \
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379 /* Is the task waiting on an event also? */ \
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380 if( pxTCB->xEventListItem.pvContainer ) \
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382 vListRemove( &( pxTCB->xEventListItem ) ); \
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384 prvAddTaskToReadyQueue( pxTCB ); \
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389 * Several functions take an xTaskHandle parameter that can optionally be NULL,
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390 * where NULL is used to indicate that the handle of the currently executing
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391 * task should be used in place of the parameter. This macro simply checks to
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392 * see if the parameter is NULL and returns a pointer to the appropriate TCB.
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394 #define prvGetTCBFromHandle( pxHandle ) ( ( pxHandle == NULL ) ? ( tskTCB * ) pxCurrentTCB : ( tskTCB * ) pxHandle )
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397 /* File private functions. --------------------------------*/
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400 * Utility to ready a TCB for a given task. Mainly just copies the parameters
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401 * into the TCB structure.
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403 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority );
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406 * Utility to ready all the lists used by the scheduler. This is called
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407 * automatically upon the creation of the first task.
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409 static void prvInitialiseTaskLists( void );
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412 * The idle task, which as all tasks is implemented as a never ending loop.
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413 * The idle task is automatically created and added to the ready lists upon
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414 * creation of the first user task.
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416 * The portTASK_FUNCTION_PROTO() macro is used to allow port/compiler specific
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417 * language extensions. The equivalent prototype for this function is:
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419 * void prvIdleTask( void *pvParameters );
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422 static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters );
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425 * Utility to free all memory allocated by the scheduler to hold a TCB,
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426 * including the stack pointed to by the TCB.
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428 * This does not free memory allocated by the task itself (i.e. memory
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429 * allocated by calls to pvPortMalloc from within the tasks application code).
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431 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
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432 static void prvDeleteTCB( tskTCB *pxTCB );
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436 * Used only by the idle task. This checks to see if anything has been placed
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437 * in the list of tasks waiting to be deleted. If so the task is cleaned up
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438 * and its TCB deleted.
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440 static void prvCheckTasksWaitingTermination( void );
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443 * Allocates memory from the heap for a TCB and associated stack. Checks the
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444 * allocation was successful.
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446 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth );
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449 * Called from vTaskList. vListTasks details all the tasks currently under
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450 * control of the scheduler. The tasks may be in one of a number of lists.
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451 * prvListTaskWithinSingleList accepts a list and details the tasks from
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452 * within just that list.
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454 * THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
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455 * NORMAL APPLICATION CODE.
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457 #if ( configUSE_TRACE_FACILITY == 1 )
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459 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus );
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464 * When a task is created, the stack of the task is filled with a known value.
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465 * This function determines the 'high water mark' of the task stack by
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466 * determining how much of the stack remains at the original preset value.
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468 #if ( configUSE_TRACE_FACILITY == 1 )
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470 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte );
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480 /*-----------------------------------------------------------
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481 * TASK CREATION API documented in task.h
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482 *----------------------------------------------------------*/
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484 signed portBASE_TYPE xTaskCreate( pdTASK_CODE pvTaskCode, const signed portCHAR * const pcName, unsigned portSHORT usStackDepth, void *pvParameters, unsigned portBASE_TYPE uxPriority, xTaskHandle *pxCreatedTask )
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486 signed portBASE_TYPE xReturn;
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488 static unsigned portBASE_TYPE uxTaskNumber = 0; /*lint !e956 Static is deliberate - this is guarded before use. */
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490 /* Allocate the memory required by the TCB and stack for the new task.
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491 checking that the allocation was successful. */
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492 pxNewTCB = prvAllocateTCBAndStack( usStackDepth );
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494 if( pxNewTCB != NULL )
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496 portSTACK_TYPE *pxTopOfStack;
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498 /* Setup the newly allocated TCB with the initial state of the task. */
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499 prvInitialiseTCBVariables( pxNewTCB, usStackDepth, pcName, uxPriority );
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501 /* Calculate the top of stack address. This depends on whether the
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502 stack grows from high memory to low (as per the 80x86) or visa versa.
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503 portSTACK_GROWTH is used to make the result positive or negative as
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504 required by the port. */
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505 #if portSTACK_GROWTH < 0
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507 pxTopOfStack = pxNewTCB->pxStack + ( pxNewTCB->usStackDepth - 1 );
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511 pxTopOfStack = pxNewTCB->pxStack;
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515 /* Initialize the TCB stack to look as if the task was already running,
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516 but had been interrupted by the scheduler. The return address is set
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517 to the start of the task function. Once the stack has been initialised
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518 the top of stack variable is updated. */
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519 pxNewTCB->pxTopOfStack = pxPortInitialiseStack( pxTopOfStack, pvTaskCode, pvParameters );
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521 /* We are going to manipulate the task queues to add this task to a
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522 ready list, so must make sure no interrupts occur. */
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523 portENTER_CRITICAL();
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525 uxCurrentNumberOfTasks++;
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526 if( uxCurrentNumberOfTasks == ( unsigned portBASE_TYPE ) 1 )
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528 /* As this is the first task it must also be the current task. */
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529 pxCurrentTCB = pxNewTCB;
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531 /* This is the first task to be created so do the preliminary
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532 initialisation required. We will not recover if this call
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533 fails, but we will report the failure. */
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534 prvInitialiseTaskLists();
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538 /* If the scheduler is not already running, make this task the
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539 current task if it is the highest priority task to be created
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541 if( xSchedulerRunning == pdFALSE )
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543 if( pxCurrentTCB->uxPriority <= uxPriority )
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545 pxCurrentTCB = pxNewTCB;
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550 /* Remember the top priority to make context switching faster. Use
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551 the priority in pxNewTCB as this has been capped to a valid value. */
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552 if( pxNewTCB->uxPriority > uxTopUsedPriority )
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554 uxTopUsedPriority = pxNewTCB->uxPriority;
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557 /* Add a counter into the TCB for tracing only. */
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558 pxNewTCB->uxTCBNumber = uxTaskNumber;
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561 prvAddTaskToReadyQueue( pxNewTCB );
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565 portEXIT_CRITICAL();
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569 xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY;
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572 if( xReturn == pdPASS )
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574 if( ( void * ) pxCreatedTask != NULL )
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576 /* Pass the TCB out - in an anonymous way. The calling function/
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577 task can use this as a handle to delete the task later if
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579 *pxCreatedTask = ( xTaskHandle ) pxNewTCB;
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582 if( xSchedulerRunning != pdFALSE )
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584 /* If the created task is of a higher priority than the current task
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585 then it should run now. */
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586 if( pxCurrentTCB->uxPriority < uxPriority )
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595 /*-----------------------------------------------------------*/
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597 #if ( INCLUDE_vTaskDelete == 1 )
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599 void vTaskDelete( xTaskHandle pxTaskToDelete )
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603 taskENTER_CRITICAL();
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605 /* Ensure a yield is performed if the current task is being
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607 if( pxTaskToDelete == pxCurrentTCB )
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609 pxTaskToDelete = NULL;
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612 /* If null is passed in here then we are deleting ourselves. */
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613 pxTCB = prvGetTCBFromHandle( pxTaskToDelete );
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615 /* Remove task from the ready list and place in the termination list.
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616 This will stop the task from be scheduled. The idle task will check
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617 the termination list and free up any memory allocated by the
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618 scheduler for the TCB and stack. */
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619 vListRemove( &( pxTCB->xGenericListItem ) );
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621 /* Is the task waiting on an event also? */
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622 if( pxTCB->xEventListItem.pvContainer )
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624 vListRemove( &( pxTCB->xEventListItem ) );
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627 vListInsertEnd( ( xList * ) &xTasksWaitingTermination, &( pxTCB->xGenericListItem ) );
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629 /* Increment the ucTasksDeleted variable so the idle task knows
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630 there is a task that has been deleted and that it should therefore
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631 check the xTasksWaitingTermination list. */
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634 taskEXIT_CRITICAL();
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636 /* Force a reschedule if we have just deleted the current task. */
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637 if( xSchedulerRunning != pdFALSE )
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639 if( ( void * ) pxTaskToDelete == NULL )
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653 /*-----------------------------------------------------------
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654 * TASK CONTROL API documented in task.h
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655 *----------------------------------------------------------*/
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657 #if ( INCLUDE_vTaskDelayUntil == 1 )
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659 void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement )
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661 portTickType xTimeToWake;
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662 portBASE_TYPE xAlreadyYielded, xShouldDelay = pdFALSE;
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666 /* Generate the tick time at which the task wants to wake. */
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667 xTimeToWake = *pxPreviousWakeTime + xTimeIncrement;
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669 if( xTickCount < *pxPreviousWakeTime )
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671 /* The tick count has overflowed since this function was
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672 lasted called. In this case the only time we should ever
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673 actually delay is if the wake time has also overflowed,
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674 and the wake time is greater than the tick time. When this
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675 is the case it is as if neither time had overflowed. */
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676 if( ( xTimeToWake < *pxPreviousWakeTime ) && ( xTimeToWake > xTickCount ) )
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678 xShouldDelay = pdTRUE;
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683 /* The tick time has not overflowed. In this case we will
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684 delay if either the wake time has overflowed, and/or the
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685 tick time is less than the wake time. */
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686 if( ( xTimeToWake < *pxPreviousWakeTime ) || ( xTimeToWake > xTickCount ) )
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688 xShouldDelay = pdTRUE;
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692 /* Update the wake time ready for the next call. */
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693 *pxPreviousWakeTime = xTimeToWake;
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697 /* We must remove ourselves from the ready list before adding
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698 ourselves to the blocked list as the same list item is used for
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700 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
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702 /* The list item will be inserted in wake time order. */
\r
703 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
705 if( xTimeToWake < xTickCount )
\r
707 /* Wake time has overflowed. Place this item in the
\r
709 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
713 /* The wake time has not overflowed, so we can use the
\r
714 current block list. */
\r
715 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
719 xAlreadyYielded = xTaskResumeAll();
\r
721 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
722 have put ourselves to sleep. */
\r
723 if( !xAlreadyYielded )
\r
730 /*-----------------------------------------------------------*/
\r
732 #if ( INCLUDE_vTaskDelay == 1 )
\r
734 void vTaskDelay( portTickType xTicksToDelay )
\r
736 portTickType xTimeToWake;
\r
737 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
739 /* A delay time of zero just forces a reschedule. */
\r
740 if( xTicksToDelay > ( portTickType ) 0 )
\r
744 /* A task that is removed from the event list while the
\r
745 scheduler is suspended will not get placed in the ready
\r
746 list or removed from the blocked list until the scheduler
\r
749 This task cannot be in an event list as it is the currently
\r
752 /* Calculate the time to wake - this may overflow but this is
\r
754 xTimeToWake = xTickCount + xTicksToDelay;
\r
756 /* We must remove ourselves from the ready list before adding
\r
757 ourselves to the blocked list as the same list item is used for
\r
759 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
761 /* The list item will be inserted in wake time order. */
\r
762 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
764 if( xTimeToWake < xTickCount )
\r
766 /* Wake time has overflowed. Place this item in the
\r
768 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
772 /* The wake time has not overflowed, so we can use the
\r
773 current block list. */
\r
774 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
777 xAlreadyYielded = xTaskResumeAll();
\r
780 /* Force a reschedule if xTaskResumeAll has not already done so, we may
\r
781 have put ourselves to sleep. */
\r
782 if( !xAlreadyYielded )
\r
789 /*-----------------------------------------------------------*/
\r
791 #if ( INCLUDE_uxTaskPriorityGet == 1 )
\r
793 unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask )
\r
796 unsigned portBASE_TYPE uxReturn;
\r
798 taskENTER_CRITICAL();
\r
800 /* If null is passed in here then we are changing the
\r
801 priority of the calling function. */
\r
802 pxTCB = prvGetTCBFromHandle( pxTask );
\r
803 uxReturn = pxTCB->uxPriority;
\r
805 taskEXIT_CRITICAL();
\r
811 /*-----------------------------------------------------------*/
\r
813 #if ( INCLUDE_vTaskPrioritySet == 1 )
\r
815 void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority )
\r
818 unsigned portBASE_TYPE uxCurrentPriority, xYieldRequired = pdFALSE;
\r
820 /* Ensure the new priority is valid. */
\r
821 if( uxNewPriority >= configMAX_PRIORITIES )
\r
823 uxNewPriority = configMAX_PRIORITIES - 1;
\r
826 taskENTER_CRITICAL();
\r
828 /* If null is passed in here then we are changing the
\r
829 priority of the calling function. */
\r
830 pxTCB = prvGetTCBFromHandle( pxTask );
\r
831 uxCurrentPriority = pxTCB->uxPriority;
\r
833 if( uxCurrentPriority != uxNewPriority )
\r
835 /* The priority change may have readied a task of higher
\r
836 priority than the calling task. */
\r
837 if( uxNewPriority > pxCurrentTCB->uxPriority )
\r
839 if( pxTask != NULL )
\r
841 /* The priority of another task is being raised. If we
\r
842 were raising the priority of the currently running task
\r
843 there would be no need to switch as it must have already
\r
844 been the highest priority task. */
\r
845 xYieldRequired = pdTRUE;
\r
848 else if( pxTask == NULL )
\r
850 /* Setting our own priority down means there may now be another
\r
851 task of higher priority that is ready to execute. */
\r
852 xYieldRequired = pdTRUE;
\r
855 pxTCB->uxPriority = uxNewPriority;
\r
856 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxNewPriority );
\r
858 /* If the task is in the blocked or suspended list we need do
\r
859 nothing more than change it's priority variable. However, if
\r
860 the task is in a ready list it needs to be removed and placed
\r
861 in the queue appropriate to its new priority. */
\r
862 if( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ uxCurrentPriority ] ), &( pxTCB->xGenericListItem ) ) )
\r
864 /* The task is currently in its ready list - remove before adding
\r
865 it to it's new ready list. As we are in a critical section we
\r
866 can do this even if the scheduler is suspended. */
\r
867 vListRemove( &( pxTCB->xGenericListItem ) );
\r
868 prvAddTaskToReadyQueue( pxTCB );
\r
871 if( xYieldRequired == pdTRUE )
\r
877 taskEXIT_CRITICAL();
\r
881 /*-----------------------------------------------------------*/
\r
883 #if ( INCLUDE_vTaskSuspend == 1 )
\r
885 void vTaskSuspend( xTaskHandle pxTaskToSuspend )
\r
889 taskENTER_CRITICAL();
\r
891 /* Ensure a yield is performed if the current task is being
\r
893 if( pxTaskToSuspend == pxCurrentTCB )
\r
895 pxTaskToSuspend = NULL;
\r
898 /* If null is passed in here then we are suspending ourselves. */
\r
899 pxTCB = prvGetTCBFromHandle( pxTaskToSuspend );
\r
901 /* Remove task from the ready/delayed list and place in the suspended list. */
\r
902 vListRemove( &( pxTCB->xGenericListItem ) );
\r
904 /* Is the task waiting on an event also? */
\r
905 if( pxTCB->xEventListItem.pvContainer )
\r
907 vListRemove( &( pxTCB->xEventListItem ) );
\r
910 vListInsertEnd( ( xList * ) &xSuspendedTaskList, &( pxTCB->xGenericListItem ) );
\r
912 taskEXIT_CRITICAL();
\r
914 /* We may have just suspended the current task. */
\r
915 if( ( void * ) pxTaskToSuspend == NULL )
\r
922 /*-----------------------------------------------------------*/
\r
924 #if ( INCLUDE_vTaskSuspend == 1 )
\r
926 void vTaskResume( xTaskHandle pxTaskToResume )
\r
930 /* Remove the task from whichever list it is currently in, and place
\r
931 it in the ready list. */
\r
932 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
934 /* The parameter cannot be NULL as it is impossible to resume the
\r
935 currently executing task. */
\r
936 if( pxTCB != NULL )
\r
938 taskENTER_CRITICAL();
\r
940 /* Is the task we are attempting to resume actually suspended? */
\r
941 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
943 /* Has the task already been resumed from within an ISR? */
\r
944 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
946 /* As we are in a critical section we can access the ready
\r
947 lists even if the scheduler is suspended. */
\r
948 vListRemove( &( pxTCB->xGenericListItem ) );
\r
949 prvAddTaskToReadyQueue( pxTCB );
\r
951 /* We may have just resumed a higher priority task. */
\r
952 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
954 /* This yield may not cause the task just resumed to run, but
\r
955 will leave the lists in the correct state for the next yield. */
\r
961 taskEXIT_CRITICAL();
\r
967 /*-----------------------------------------------------------*/
\r
969 #if ( ( INCLUDE_xTaskResumeFromISR == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
971 portBASE_TYPE xTaskResumeFromISR( xTaskHandle pxTaskToResume )
\r
973 portBASE_TYPE xYieldRequired = pdFALSE;
\r
976 pxTCB = ( tskTCB * ) pxTaskToResume;
\r
978 /* Is the task we are attempting to resume actually suspended? */
\r
979 if( listIS_CONTAINED_WITHIN( &xSuspendedTaskList, &( pxTCB->xGenericListItem ) ) != pdFALSE )
\r
981 /* Has the task already been resumed from within an ISR? */
\r
982 if( listIS_CONTAINED_WITHIN( &xPendingReadyList, &( pxTCB->xEventListItem ) ) != pdTRUE )
\r
984 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
986 xYieldRequired = ( pxTCB->uxPriority >= pxCurrentTCB->uxPriority );
\r
987 vListRemove( &( pxTCB->xGenericListItem ) );
\r
988 prvAddTaskToReadyQueue( pxTCB );
\r
992 /* We cannot access the delayed or ready lists, so will hold this
\r
993 task pending until the scheduler is resumed, at which point a
\r
994 yield will be preformed if necessary. */
\r
995 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxTCB->xEventListItem ) );
\r
1000 return xYieldRequired;
\r
1008 /*-----------------------------------------------------------
\r
1009 * PUBLIC SCHEDULER CONTROL documented in task.h
\r
1010 *----------------------------------------------------------*/
\r
1013 void vTaskStartScheduler( void )
\r
1015 portBASE_TYPE xReturn;
\r
1017 /* Add the idle task at the lowest priority. */
\r
1018 xReturn = xTaskCreate( prvIdleTask, ( signed portCHAR * ) "IDLE", tskIDLE_STACK_SIZE, ( void * ) NULL, tskIDLE_PRIORITY, ( xTaskHandle * ) NULL );
\r
1020 if( xReturn == pdPASS )
\r
1022 /* Interrupts are turned off here, to ensure a tick does not occur
\r
1023 before or during the call to xPortStartScheduler(). The stacks of
\r
1024 the created tasks contain a status word with interrupts switched on
\r
1025 so interrupts will automatically get re-enabled when the first task
\r
1028 STEPPING THROUGH HERE USING A DEBUGGER CAN CAUSE BIG PROBLEMS IF THE
\r
1029 DEBUGGER ALLOWS INTERRUPTS TO BE PROCESSED. */
\r
1030 portDISABLE_INTERRUPTS();
\r
1032 xSchedulerRunning = pdTRUE;
\r
1033 xTickCount = ( portTickType ) 0;
\r
1035 /* Setting up the timer tick is hardware specific and thus in the
\r
1036 portable interface. */
\r
1037 if( xPortStartScheduler() )
\r
1039 /* Should not reach here as if the scheduler is running the
\r
1040 function will not return. */
\r
1044 /* Should only reach here if a task calls xTaskEndScheduler(). */
\r
1048 /*-----------------------------------------------------------*/
\r
1050 void vTaskEndScheduler( void )
\r
1052 /* Stop the scheduler interrupts and call the portable scheduler end
\r
1053 routine so the original ISRs can be restored if necessary. The port
\r
1054 layer must ensure interrupts enable bit is left in the correct state. */
\r
1055 portDISABLE_INTERRUPTS();
\r
1056 xSchedulerRunning = pdFALSE;
\r
1057 vPortEndScheduler();
\r
1059 /*----------------------------------------------------------*/
\r
1061 void vTaskSuspendAll( void )
\r
1063 portENTER_CRITICAL();
\r
1064 ++uxSchedulerSuspended;
\r
1065 portEXIT_CRITICAL();
\r
1067 /*----------------------------------------------------------*/
\r
1069 signed portBASE_TYPE xTaskResumeAll( void )
\r
1071 register tskTCB *pxTCB;
\r
1072 signed portBASE_TYPE xAlreadyYielded = pdFALSE;
\r
1074 /* It is possible that an ISR caused a task to be removed from an event
\r
1075 list while the scheduler was suspended. If this was the case then the
\r
1076 removed task will have been added to the xPendingReadyList. Once the
\r
1077 scheduler has been resumed it is safe to move all the pending ready
\r
1078 tasks from this list into their appropriate ready list. */
\r
1079 portENTER_CRITICAL();
\r
1081 --uxSchedulerSuspended;
\r
1083 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1085 if( uxCurrentNumberOfTasks > ( unsigned portBASE_TYPE ) 0 )
\r
1087 portBASE_TYPE xYieldRequired = pdFALSE;
\r
1089 /* Move any readied tasks from the pending list into the
\r
1090 appropriate ready list. */
\r
1091 while( ( pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xPendingReadyList ) ) ) != NULL )
\r
1093 vListRemove( &( pxTCB->xEventListItem ) );
\r
1094 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1095 prvAddTaskToReadyQueue( pxTCB );
\r
1097 /* If we have moved a task that has a priority higher than
\r
1098 the current task then we should yield. */
\r
1099 if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1101 xYieldRequired = pdTRUE;
\r
1105 /* If any ticks occurred while the scheduler was suspended then
\r
1106 they should be processed now. This ensures the tick count does not
\r
1107 slip, and that any delayed tasks are resumed at the correct time. */
\r
1108 if( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1110 while( uxMissedTicks > ( unsigned portBASE_TYPE ) 0 )
\r
1112 vTaskIncrementTick();
\r
1116 /* As we have processed some ticks it is appropriate to yield
\r
1117 to ensure the highest priority task that is ready to run is
\r
1118 the task actually running. */
\r
1119 xYieldRequired = pdTRUE;
\r
1122 if( ( xYieldRequired == pdTRUE ) || ( xMissedYield == pdTRUE ) )
\r
1124 xAlreadyYielded = pdTRUE;
\r
1125 xMissedYield = pdFALSE;
\r
1131 portEXIT_CRITICAL();
\r
1133 return xAlreadyYielded;
\r
1141 /*-----------------------------------------------------------
\r
1142 * PUBLIC TASK UTILITIES documented in task.h
\r
1143 *----------------------------------------------------------*/
\r
1147 portTickType xTaskGetTickCount( void )
\r
1149 portTickType xTicks;
\r
1151 /* Critical section required if running on a 16 bit processor. */
\r
1152 taskENTER_CRITICAL();
\r
1154 xTicks = xTickCount;
\r
1156 taskEXIT_CRITICAL();
\r
1160 /*-----------------------------------------------------------*/
\r
1162 unsigned portBASE_TYPE uxTaskGetNumberOfTasks( void )
\r
1164 unsigned portBASE_TYPE uxNumberOfTasks;
\r
1166 taskENTER_CRITICAL();
\r
1167 uxNumberOfTasks = uxCurrentNumberOfTasks;
\r
1168 taskEXIT_CRITICAL();
\r
1170 return uxNumberOfTasks;
\r
1172 /*-----------------------------------------------------------*/
\r
1174 #if ( ( configUSE_TRACE_FACILITY == 1 ) && ( INCLUDE_vTaskDelete == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1176 void vTaskList( signed portCHAR *pcWriteBuffer )
\r
1178 unsigned portBASE_TYPE uxQueue;
\r
1180 /* This is a VERY costly function that should be used for debug only.
\r
1181 It leaves interrupts disabled for a LONG time. */
\r
1183 vTaskSuspendAll();
\r
1185 /* Run through all the lists that could potentially contain a TCB and
\r
1186 report the task name, state and stack high water mark. */
\r
1188 pcWriteBuffer[ 0 ] = ( signed portCHAR ) 0x00;
\r
1189 strcat( ( portCHAR * ) pcWriteBuffer, ( const portCHAR * ) "\r\n" );
\r
1191 uxQueue = uxTopUsedPriority + 1;
\r
1197 if( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxQueue ] ) ) )
\r
1199 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &( pxReadyTasksLists[ uxQueue ] ), tskREADY_CHAR );
\r
1201 }while( uxQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1203 if( !listLIST_IS_EMPTY( pxDelayedTaskList ) )
\r
1205 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxDelayedTaskList, tskBLOCKED_CHAR );
\r
1208 if( !listLIST_IS_EMPTY( pxOverflowDelayedTaskList ) )
\r
1210 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) pxOverflowDelayedTaskList, tskBLOCKED_CHAR );
\r
1213 if( !listLIST_IS_EMPTY( &xTasksWaitingTermination ) )
\r
1215 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xTasksWaitingTermination, tskDELETED_CHAR );
\r
1218 if( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1220 prvListTaskWithinSingleList( pcWriteBuffer, ( xList * ) &xSuspendedTaskList, tskSUSPENDED_CHAR );
\r
1227 /*----------------------------------------------------------*/
\r
1229 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1231 void vTaskStartTrace( signed portCHAR * pcBuffer, unsigned portLONG ulBufferSize )
\r
1233 portENTER_CRITICAL();
\r
1235 pcTraceBuffer = ( volatile signed portCHAR * volatile )pcBuffer;
\r
1236 pcTraceBufferStart = pcBuffer;
\r
1237 pcTraceBufferEnd = pcBuffer + ( ulBufferSize - tskSIZE_OF_EACH_TRACE_LINE );
\r
1238 xTracing = pdTRUE;
\r
1240 portEXIT_CRITICAL();
\r
1244 /*----------------------------------------------------------*/
\r
1246 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1248 unsigned portLONG ulTaskEndTrace( void )
\r
1250 unsigned portLONG ulBufferLength;
\r
1252 portENTER_CRITICAL();
\r
1253 xTracing = pdFALSE;
\r
1254 portEXIT_CRITICAL();
\r
1256 ulBufferLength = ( unsigned portLONG ) ( pcTraceBuffer - pcTraceBufferStart );
\r
1258 return ulBufferLength;
\r
1265 /*-----------------------------------------------------------
\r
1266 * SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
\r
1267 * documented in task.h
\r
1268 *----------------------------------------------------------*/
\r
1271 inline void vTaskIncrementTick( void )
\r
1273 /* Called by the portable layer each time a tick interrupt occurs.
\r
1274 Increments the tick then checks to see if the new tick value will cause any
\r
1275 tasks to be unblocked. */
\r
1276 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1279 if( xTickCount == ( portTickType ) 0 )
\r
1283 /* Tick count has overflowed so we need to swap the delay lists.
\r
1284 If there are any items in pxDelayedTaskList here then there is
\r
1286 pxTemp = pxDelayedTaskList;
\r
1287 pxDelayedTaskList = pxOverflowDelayedTaskList;
\r
1288 pxOverflowDelayedTaskList = pxTemp;
\r
1289 xNumOfOverflows++;
\r
1292 /* See if this tick has made a timeout expire. */
\r
1293 prvCheckDelayedTasks();
\r
1299 /* The tick hook gets called at regular intervals, even if the
\r
1300 scheduler is locked. */
\r
1301 #if ( configUSE_TICK_HOOK == 1 )
\r
1303 extern void vApplicationTickHook( void );
\r
1305 vApplicationTickHook();
\r
1310 #if ( configUSE_TICK_HOOK == 1 )
\r
1312 extern void vApplicationTickHook( void );
\r
1314 /* Guard against the tick hook being called when the missed tick
\r
1315 count is being unwound (when the scheduler is being unlocked. */
\r
1316 if( uxMissedTicks == 0 )
\r
1318 vApplicationTickHook();
\r
1323 /*-----------------------------------------------------------*/
\r
1325 #if ( ( INCLUDE_vTaskCleanUpResources == 1 ) && ( INCLUDE_vTaskSuspend == 1 ) )
\r
1327 void vTaskCleanUpResources( void )
\r
1329 unsigned portSHORT usQueue;
\r
1330 volatile tskTCB *pxTCB;
\r
1332 usQueue = ( unsigned portSHORT ) uxTopUsedPriority + ( unsigned portSHORT ) 1;
\r
1334 /* Remove any TCB's from the ready queues. */
\r
1339 while( !listLIST_IS_EMPTY( &( pxReadyTasksLists[ usQueue ] ) ) )
\r
1341 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &( pxReadyTasksLists[ usQueue ] ) );
\r
1342 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1344 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1346 }while( usQueue > ( unsigned portSHORT ) tskIDLE_PRIORITY );
\r
1348 /* Remove any TCB's from the delayed queue. */
\r
1349 while( !listLIST_IS_EMPTY( &xDelayedTaskList1 ) )
\r
1351 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList1 );
\r
1352 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1354 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1357 /* Remove any TCB's from the overflow delayed queue. */
\r
1358 while( !listLIST_IS_EMPTY( &xDelayedTaskList2 ) )
\r
1360 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xDelayedTaskList2 );
\r
1361 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1363 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1366 while( !listLIST_IS_EMPTY( &xSuspendedTaskList ) )
\r
1368 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xSuspendedTaskList );
\r
1369 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1371 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1374 while( !listLIST_IS_EMPTY( &xPendingReadyList ) )
\r
1376 listGET_OWNER_OF_NEXT_ENTRY( pxTCB, &xPendingReadyList );
\r
1377 vListRemove( ( xListItem * ) &( pxTCB->xGenericListItem ) );
\r
1379 prvDeleteTCB( ( tskTCB * ) pxTCB );
\r
1384 /*-----------------------------------------------------------*/
\r
1386 void vTaskSwitchContext( void )
\r
1388 if( uxSchedulerSuspended != ( unsigned portBASE_TYPE ) pdFALSE )
\r
1390 /* The scheduler is currently suspended - do not allow a context
\r
1392 xMissedYield = pdTRUE;
\r
1396 /* Find the highest priority queue that contains ready tasks. */
\r
1397 while( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxTopReadyPriority ] ) ) )
\r
1399 --uxTopReadyPriority;
\r
1402 /* listGET_OWNER_OF_NEXT_ENTRY walks through the list, so the tasks of the
\r
1403 same priority get an equal share of the processor time. */
\r
1404 listGET_OWNER_OF_NEXT_ENTRY( pxCurrentTCB, &( pxReadyTasksLists[ uxTopReadyPriority ] ) );
\r
1405 vWriteTraceToBuffer();
\r
1407 /*-----------------------------------------------------------*/
\r
1409 void vTaskPlaceOnEventList( xList *pxEventList, portTickType xTicksToWait )
\r
1411 portTickType xTimeToWake;
\r
1413 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1414 SCHEDULER SUSPENDED. */
\r
1416 /* Place the event list item of the TCB in the appropriate event list.
\r
1417 This is placed in the list in priority order so the highest priority task
\r
1418 is the first to be woken by the event. */
\r
1419 vListInsert( ( xList * ) pxEventList, ( xListItem * ) &( pxCurrentTCB->xEventListItem ) );
\r
1421 /* Calculate the time at which the task should be woken if the event does
\r
1422 not occur. This may overflow but this doesn't matter. */
\r
1423 xTimeToWake = xTickCount + xTicksToWait;
\r
1425 /* We must remove ourselves from the ready list before adding ourselves
\r
1426 to the blocked list as the same list item is used for both lists. We have
\r
1427 exclusive access to the ready lists as the scheduler is locked. */
\r
1428 vListRemove( ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1430 listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );
\r
1432 if( xTimeToWake < xTickCount )
\r
1434 /* Wake time has overflowed. Place this item in the overflow list. */
\r
1435 vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1439 /* The wake time has not overflowed, so we can use the current block list. */
\r
1440 vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
\r
1443 /*-----------------------------------------------------------*/
\r
1445 signed portBASE_TYPE xTaskRemoveFromEventList( const xList *pxEventList )
\r
1447 tskTCB *pxUnblockedTCB;
\r
1448 portBASE_TYPE xReturn;
\r
1450 /* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
\r
1451 SCHEDULER SUSPENDED. It can also be called from within an ISR. */
\r
1453 /* The event list is sorted in priority order, so we can remove the
\r
1454 first in the list, remove the TCB from the delayed list, and add
\r
1455 it to the ready list.
\r
1457 If an event is for a queue that is locked then this function will never
\r
1458 get called - the lock count on the queue will get modified instead. This
\r
1459 means we can always expect exclusive access to the event list here. */
\r
1460 pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
\r
1461 vListRemove( &( pxUnblockedTCB->xEventListItem ) );
\r
1463 if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
\r
1465 vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
\r
1466 prvAddTaskToReadyQueue( pxUnblockedTCB );
\r
1470 /* We cannot access the delayed or ready lists, so will hold this
\r
1471 task pending until the scheduler is resumed. */
\r
1472 vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
\r
1475 if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
\r
1477 /* Return true if the task removed from the event list has
\r
1478 a higher priority than the calling task. This allows
\r
1479 the calling task to know if it should force a context
\r
1485 xReturn = pdFALSE;
\r
1490 /*-----------------------------------------------------------*/
\r
1492 void vTaskSetTimeOutState( xTimeOutType *pxTimeOut )
\r
1494 pxTimeOut->xOverflowCount = xNumOfOverflows;
\r
1495 pxTimeOut->xTimeOnEntering = xTickCount;
\r
1497 /*-----------------------------------------------------------*/
\r
1499 portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType *pxTimeOut, portTickType *pxTicksToWait )
\r
1501 portBASE_TYPE xReturn;
\r
1503 if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( xTickCount > pxTimeOut->xTimeOnEntering ) )
\r
1505 /* The tick count is greater than the time at which vTaskSetTimeout()
\r
1506 was called, but has also overflowed since vTaskSetTimeOut() was called.
\r
1507 It must have wrapped all the way around and gone past us again. This
\r
1508 passed since vTaskSetTimeout() was called. */
\r
1511 else if( ( xTickCount - pxTimeOut->xTimeOnEntering ) < *pxTicksToWait )
\r
1513 /* Not a genuine timeout. Adjust parameters for time remaining. */
\r
1514 *pxTicksToWait -= ( xTickCount - pxTimeOut->xTimeOnEntering );
\r
1515 vTaskSetTimeOutState( pxTimeOut );
\r
1516 xReturn = pdFALSE;
\r
1525 /*-----------------------------------------------------------*/
\r
1527 void vTaskMissedYield( void )
\r
1529 xMissedYield = pdTRUE;
\r
1533 * -----------------------------------------------------------
\r
1535 * ----------------------------------------------------------
\r
1537 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
\r
1538 * language extensions. The equivalent prototype for this function is:
\r
1540 * void prvIdleTask( void *pvParameters );
\r
1543 static portTASK_FUNCTION( prvIdleTask, pvParameters )
\r
1545 /* Stop warnings. */
\r
1546 ( void ) pvParameters;
\r
1550 /* See if any tasks have been deleted. */
\r
1551 prvCheckTasksWaitingTermination();
\r
1553 #if ( configUSE_PREEMPTION == 0 )
\r
1555 /* If we are not using preemption we keep forcing a task switch to
\r
1556 see if any other task has become available. If we are using
\r
1557 preemption we don't need to do this as any task becoming available
\r
1558 will automatically get the processor anyway. */
\r
1563 #if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
\r
1565 /* When using preemption tasks of equal priority will be
\r
1566 timesliced. If a task that is sharing the idle priority is ready
\r
1567 to run then the idle task should yield before the end of the
\r
1570 A critical region is not required here as we are just reading from
\r
1571 the list, and an occasional incorrect value will not matter. If
\r
1572 the ready list at the idle priority contains more than one task
\r
1573 then a task other than the idle task is ready to execute. */
\r
1574 if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
\r
1581 #if ( configUSE_IDLE_HOOK == 1 )
\r
1583 extern void vApplicationIdleHook( void );
\r
1585 /* Call the user defined function from within the idle task. This
\r
1586 allows the application designer to add background functionality
\r
1587 without the overhead of a separate task.
\r
1588 NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
\r
1589 CALL A FUNCTION THAT MIGHT BLOCK. */
\r
1590 vApplicationIdleHook();
\r
1594 } /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */
\r
1602 /*-----------------------------------------------------------
\r
1603 * File private functions documented at the top of the file.
\r
1604 *----------------------------------------------------------*/
\r
1608 static void prvInitialiseTCBVariables( tskTCB *pxTCB, unsigned portSHORT usStackDepth, const signed portCHAR * const pcName, unsigned portBASE_TYPE uxPriority )
\r
1610 pxTCB->usStackDepth = usStackDepth;
\r
1612 /* Store the function name in the TCB. */
\r
1613 strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned portSHORT ) configMAX_TASK_NAME_LEN );
\r
1614 pxTCB->pcTaskName[ ( unsigned portSHORT ) configMAX_TASK_NAME_LEN - ( unsigned portSHORT ) 1 ] = '\0';
\r
1616 /* This is used as an array index so must ensure it's not too large. */
\r
1617 if( uxPriority >= configMAX_PRIORITIES )
\r
1619 uxPriority = configMAX_PRIORITIES - 1;
\r
1622 pxTCB->uxPriority = uxPriority;
\r
1624 vListInitialiseItem( &( pxTCB->xGenericListItem ) );
\r
1625 vListInitialiseItem( &( pxTCB->xEventListItem ) );
\r
1627 /* Set the pxTCB as a link back from the xListItem. This is so we can get
\r
1628 back to the containing TCB from a generic item in a list. */
\r
1629 listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );
\r
1631 /* Event lists are always in priority order. */
\r
1632 listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
\r
1633 listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
\r
1635 /*-----------------------------------------------------------*/
\r
1637 static void prvInitialiseTaskLists( void )
\r
1639 unsigned portBASE_TYPE uxPriority;
\r
1641 for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
\r
1643 vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
\r
1646 vListInitialise( ( xList * ) &xDelayedTaskList1 );
\r
1647 vListInitialise( ( xList * ) &xDelayedTaskList2 );
\r
1648 vListInitialise( ( xList * ) &xPendingReadyList );
\r
1650 #if ( INCLUDE_vTaskDelete == 1 )
\r
1652 vListInitialise( ( xList * ) &xTasksWaitingTermination );
\r
1656 #if ( INCLUDE_vTaskSuspend == 1 )
\r
1658 vListInitialise( ( xList * ) &xSuspendedTaskList );
\r
1662 /* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
\r
1664 pxDelayedTaskList = &xDelayedTaskList1;
\r
1665 pxOverflowDelayedTaskList = &xDelayedTaskList2;
\r
1667 /*-----------------------------------------------------------*/
\r
1669 static void prvCheckTasksWaitingTermination( void )
\r
1671 #if ( INCLUDE_vTaskDelete == 1 )
\r
1673 portBASE_TYPE xListIsEmpty;
\r
1675 /* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
\r
1676 too often in the idle task. */
\r
1677 if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
\r
1679 vTaskSuspendAll();
\r
1680 xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
\r
1683 if( !xListIsEmpty )
\r
1687 portENTER_CRITICAL();
\r
1689 pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
\r
1690 vListRemove( &( pxTCB->xGenericListItem ) );
\r
1691 --uxCurrentNumberOfTasks;
\r
1694 portEXIT_CRITICAL();
\r
1696 prvDeleteTCB( pxTCB );
\r
1702 /*-----------------------------------------------------------*/
\r
1704 static tskTCB *prvAllocateTCBAndStack( unsigned portSHORT usStackDepth )
\r
1708 /* Allocate space for the TCB. Where the memory comes from depends on
\r
1709 the implementation of the port malloc function. */
\r
1710 pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );
\r
1712 if( pxNewTCB != NULL )
\r
1714 /* Allocate space for the stack used by the task being created.
\r
1715 The base of the stack memory stored in the TCB so the task can
\r
1716 be deleted later if required. */
\r
1717 pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMalloc( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) );
\r
1719 if( pxNewTCB->pxStack == NULL )
\r
1721 /* Could not allocate the stack. Delete the allocated TCB. */
\r
1722 vPortFree( pxNewTCB );
\r
1727 /* Just to help debugging. */
\r
1728 memset( pxNewTCB->pxStack, tskSTACK_FILL_BYTE, usStackDepth * sizeof( portSTACK_TYPE ) );
\r
1734 /*-----------------------------------------------------------*/
\r
1736 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1738 static void prvListTaskWithinSingleList( signed portCHAR *pcWriteBuffer, xList *pxList, signed portCHAR cStatus )
\r
1740 volatile tskTCB *pxNextTCB, *pxFirstTCB;
\r
1741 static portCHAR pcStatusString[ 50 ];
\r
1742 unsigned portSHORT usStackRemaining;
\r
1744 /* Write the details of all the TCB's in pxList into the buffer. */
\r
1745 listGET_OWNER_OF_NEXT_ENTRY( pxFirstTCB, pxList );
\r
1748 listGET_OWNER_OF_NEXT_ENTRY( pxNextTCB, pxList );
\r
1749 usStackRemaining = usTaskCheckFreeStackSpace( ( unsigned portCHAR * ) pxNextTCB->pxStack );
\r
1750 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
1751 strcat( ( portCHAR * ) pcWriteBuffer, ( portCHAR * ) pcStatusString );
\r
1753 } while( pxNextTCB != pxFirstTCB );
\r
1757 /*-----------------------------------------------------------*/
\r
1759 #if ( configUSE_TRACE_FACILITY == 1 )
\r
1760 unsigned portSHORT usTaskCheckFreeStackSpace( const unsigned portCHAR *pucStackByte )
\r
1762 register unsigned portSHORT usCount = 0;
\r
1764 while( *pucStackByte == tskSTACK_FILL_BYTE )
\r
1766 pucStackByte -= portSTACK_GROWTH;
\r
1770 usCount /= sizeof( portSTACK_TYPE );
\r
1775 /*-----------------------------------------------------------*/
\r
1779 #if ( ( INCLUDE_vTaskDelete == 1 ) || ( INCLUDE_vTaskCleanUpResources == 1 ) )
\r
1781 static void prvDeleteTCB( tskTCB *pxTCB )
\r
1783 /* Free up the memory allocated by the scheduler for the task. It is up to
\r
1784 the task to free any memory allocated at the application level. */
\r
1785 vPortFree( pxTCB->pxStack );
\r
1786 vPortFree( pxTCB );
\r
1792 /*-----------------------------------------------------------*/
\r
1794 #if ( INCLUDE_xTaskGetCurrentTaskHandle == 1 )
\r
1796 xTaskHandle xTaskGetCurrentTaskHandle( void )
\r
1798 xTaskHandle xReturn;
\r
1800 portENTER_CRITICAL();
\r
1802 xReturn = ( xTaskHandle ) pxCurrentTCB;
\r
1804 portEXIT_CRITICAL();
\r
projects / freertos / blob