2 FreeRTOS.org V4.1.3 - 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 + More use of 8bit data types.
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37 + Function name prefixes changed where the data type returned has changed.
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41 + Added the queue locking mechanism and make more use of the scheduler
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42 suspension feature to minimise the time interrupts have to be disabled
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43 when accessing a queue.
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47 + Explicit use of 'signed' qualifier on portCHAR types added.
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51 + API changes as described on the FreeRTOS.org WEB site.
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55 + Added the queue functions that can be used from co-routines.
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59 + Added a loop within xQueueSend() and xQueueReceive() to prevent the
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60 functions exiting when a block time remains and the function has
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63 Changes from V4.1.2:
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65 + BUG FIX: Removed the call to prvIsQueueEmpty from within xQueueCRReceive
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66 as it exited with interrupts enabled. Thanks Paul Katz.
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71 #include "FreeRTOS.h"
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73 #include "croutine.h"
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75 /*-----------------------------------------------------------
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76 * PUBLIC LIST API documented in list.h
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77 *----------------------------------------------------------*/
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79 /* Constants used with the cRxLock and cTxLock structure members. */
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80 #define queueUNLOCKED ( ( signed portBASE_TYPE ) -1 )
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81 #define queueERRONEOUS_UNBLOCK ( -1 )
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84 * Definition of the queue used by the scheduler.
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85 * Items are queued by copy, not reference.
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87 typedef struct QueueDefinition
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89 signed portCHAR *pcHead; /*< Points to the beginning of the queue storage area. */
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90 signed portCHAR *pcTail; /*< Points to the byte at the end of the queue storage area. Once more byte is allocated than necessary to store the queue items, this is used as a marker. */
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92 signed portCHAR *pcWriteTo; /*< Points to the free next place in the storage area. */
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93 signed portCHAR *pcReadFrom; /*< Points to the last place that a queued item was read from. */
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95 xList xTasksWaitingToSend; /*< List of tasks that are blocked waiting to post onto this queue. Stored in priority order. */
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96 xList xTasksWaitingToReceive; /*< List of tasks that are blocked waiting to read from this queue. Stored in priority order. */
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98 unsigned portBASE_TYPE uxMessagesWaiting;/*< The number of items currently in the queue. */
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99 unsigned portBASE_TYPE uxLength; /*< The length of the queue defined as the number of items it will hold, not the number of bytes. */
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100 unsigned portBASE_TYPE uxItemSize; /*< The size of each items that the queue will hold. */
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102 signed portBASE_TYPE xRxLock; /*< Stores the number of items received from the queue (removed from the queue) while the queue was locked. Set to queueUNLOCKED when the queue is not locked. */
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103 signed portBASE_TYPE xTxLock; /*< Stores the number of items transmitted to the queue (added to the queue) while the queue was locked. Set to queueUNLOCKED when the queue is not locked. */
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105 /*-----------------------------------------------------------*/
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108 * Inside this file xQueueHandle is a pointer to a xQUEUE structure.
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109 * To keep the definition private the API header file defines it as a
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112 typedef xQUEUE * xQueueHandle;
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115 * Prototypes for public functions are included here so we don't have to
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116 * include the API header file (as it defines xQueueHandle differently). These
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117 * functions are documented in the API header file.
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119 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize );
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120 signed portBASE_TYPE xQueueSend( xQueueHandle xQueue, const void * pvItemToQueue, portTickType xTicksToWait );
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121 unsigned portBASE_TYPE uxQueueMessagesWaiting( xQueueHandle pxQueue );
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122 void vQueueDelete( xQueueHandle xQueue );
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123 signed portBASE_TYPE xQueueSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xTaskPreviouslyWoken );
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124 signed portBASE_TYPE xQueueReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );
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125 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
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127 #if configUSE_CO_ROUTINES == 1
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128 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken );
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129 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
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130 signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait );
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131 signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );
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135 * Unlocks a queue locked by a call to prvLockQueue. Locking a queue does not
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136 * prevent an ISR from adding or removing items to the queue, but does prevent
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137 * an ISR from removing tasks from the queue event lists. If an ISR finds a
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138 * queue is locked it will instead increment the appropriate queue lock count
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139 * to indicate that a task may require unblocking. When the queue in unlocked
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140 * these lock counts are inspected, and the appropriate action taken.
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142 static void prvUnlockQueue( xQueueHandle pxQueue );
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145 * Uses a critical section to determine if there is any data in a queue.
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147 * @return pdTRUE if the queue contains no items, otherwise pdFALSE.
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149 static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue );
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152 * Uses a critical section to determine if there is any space in a queue.
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154 * @return pdTRUE if there is no space, otherwise pdFALSE;
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156 static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue );
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159 * Macro that copies an item into the queue. This is done by copying the item
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160 * byte for byte, not by reference. Updates the queue state to ensure it's
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161 * integrity after the copy.
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163 #define prvCopyQueueData( pxQueue, pvItemToQueue ) \
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165 memcpy( ( void * ) pxQueue->pcWriteTo, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize ); \
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166 ++( pxQueue->uxMessagesWaiting ); \
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167 pxQueue->pcWriteTo += pxQueue->uxItemSize; \
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168 if( pxQueue->pcWriteTo >= pxQueue->pcTail ) \
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170 pxQueue->pcWriteTo = pxQueue->pcHead; \
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173 /*-----------------------------------------------------------*/
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176 * Macro to mark a queue as locked. Locking a queue prevents an ISR from
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177 * accessing the queue event lists.
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179 #define prvLockQueue( pxQueue ) \
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181 taskENTER_CRITICAL(); \
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182 ++( pxQueue->xRxLock ); \
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183 ++( pxQueue->xTxLock ); \
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184 taskEXIT_CRITICAL(); \
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186 /*-----------------------------------------------------------*/
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189 /*-----------------------------------------------------------
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190 * PUBLIC QUEUE MANAGEMENT API documented in queue.h
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191 *----------------------------------------------------------*/
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193 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize )
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195 xQUEUE *pxNewQueue;
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196 size_t xQueueSizeInBytes;
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198 /* Allocate the new queue structure. */
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199 if( uxQueueLength > ( unsigned portBASE_TYPE ) 0 )
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201 pxNewQueue = ( xQUEUE * ) pvPortMalloc( sizeof( xQUEUE ) );
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202 if( pxNewQueue != NULL )
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204 /* Create the list of pointers to queue items. The queue is one byte
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205 longer than asked for to make wrap checking easier/faster. */
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206 xQueueSizeInBytes = ( size_t ) ( uxQueueLength * uxItemSize ) + ( size_t ) 1;
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208 pxNewQueue->pcHead = ( signed portCHAR * ) pvPortMalloc( xQueueSizeInBytes );
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209 if( pxNewQueue->pcHead != NULL )
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211 /* Initialise the queue members as described above where the
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212 queue type is defined. */
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213 pxNewQueue->pcTail = pxNewQueue->pcHead + ( uxQueueLength * uxItemSize );
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214 pxNewQueue->uxMessagesWaiting = 0;
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215 pxNewQueue->pcWriteTo = pxNewQueue->pcHead;
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216 pxNewQueue->pcReadFrom = pxNewQueue->pcHead + ( ( uxQueueLength - 1 ) * uxItemSize );
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217 pxNewQueue->uxLength = uxQueueLength;
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218 pxNewQueue->uxItemSize = uxItemSize;
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219 pxNewQueue->xRxLock = queueUNLOCKED;
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220 pxNewQueue->xTxLock = queueUNLOCKED;
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222 /* Likewise ensure the event queues start with the correct state. */
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223 vListInitialise( &( pxNewQueue->xTasksWaitingToSend ) );
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224 vListInitialise( &( pxNewQueue->xTasksWaitingToReceive ) );
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230 vPortFree( pxNewQueue );
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235 /* Will only reach here if we could not allocate enough memory or no memory
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239 /*-----------------------------------------------------------*/
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241 signed portBASE_TYPE xQueueSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait )
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243 signed portBASE_TYPE xReturn = pdPASS;
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244 xTimeOutType xTimeOut;
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246 /* Make sure other tasks do not access the queue. */
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249 /* Capture the current time status for future reference. */
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250 vTaskSetTimeOutState( &xTimeOut );
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252 /* It is important that this is the only thread/ISR that modifies the
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253 ready or delayed lists until xTaskResumeAll() is called. Places where
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254 the ready/delayed lists are modified include:
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256 + vTaskDelay() - Nothing can call vTaskDelay as the scheduler is
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257 suspended, vTaskDelay() cannot be called from an ISR.
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258 + vTaskPrioritySet() - Has a critical section around the access.
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259 + vTaskSwitchContext() - This will not get executed while the scheduler
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261 + prvCheckDelayedTasks() - This will not get executed while the
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262 scheduler is suspended.
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263 + xTaskCreate() - Has a critical section around the access.
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264 + vTaskResume() - Has a critical section around the access.
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265 + xTaskResumeAll() - Has a critical section around the access.
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266 + xTaskRemoveFromEventList - Checks to see if the scheduler is
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267 suspended. If so then the TCB being removed from the event is
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268 removed from the event and added to the xPendingReadyList.
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271 /* Make sure interrupts do not access the queue event list. */
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272 prvLockQueue( pxQueue );
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274 /* It is important that interrupts to not access the event list of the
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275 queue being modified here. Places where the event list is modified
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278 + xQueueSendFromISR(). This checks the lock on the queue to see if
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279 it has access. If the queue is locked then the Tx lock count is
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280 incremented to signify that a task waiting for data can be made ready
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281 once the queue lock is removed. If the queue is not locked then
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282 a task can be moved from the event list, but will not be removed
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283 from the delayed list or placed in the ready list until the scheduler
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286 + xQueueReceiveFromISR(). As per xQueueSendFromISR().
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289 /* If the queue is already full we may have to block. */
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292 if( prvIsQueueFull( pxQueue ) )
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294 /* The queue is full - do we want to block or just leave without
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296 if( xTicksToWait > ( portTickType ) 0 )
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298 /* We are going to place ourselves on the xTasksWaitingToSend event
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299 list, and will get woken should the delay expire, or space become
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300 available on the queue.
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302 As detailed above we do not require mutual exclusion on the event
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303 list as nothing else can modify it or the ready lists while we
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304 have the scheduler suspended and queue locked.
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306 It is possible that an ISR has removed data from the queue since we
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307 checked if any was available. If this is the case then the data
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308 will have been copied from the queue, and the queue variables
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309 updated, but the event list will not yet have been checked to see if
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310 anything is waiting as the queue is locked. */
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311 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );
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313 /* Force a context switch now as we are blocked. We can do
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314 this from within a critical section as the task we are
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315 switching to has its own context. When we return here (i.e. we
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316 unblock) we will leave the critical section as normal.
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318 It is possible that an ISR has caused an event on an unrelated and
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319 unlocked queue. If this was the case then the event list for that
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320 queue will have been updated but the ready lists left unchanged -
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321 instead the readied task will have been added to the pending ready
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323 taskENTER_CRITICAL();
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325 /* We can safely unlock the queue and scheduler here as
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326 interrupts are disabled. We must not yield with anything
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327 locked, but we can yield from within a critical section.
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329 Tasks that have been placed on the pending ready list cannot
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330 be tasks that are waiting for events on this queue. See
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331 in comment xTaskRemoveFromEventList(). */
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332 prvUnlockQueue( pxQueue );
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334 /* Resuming the scheduler may cause a yield. If so then there
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335 is no point yielding again here. */
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336 if( !xTaskResumeAll() )
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341 /* We want to check to see if the queue is still full
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342 before leaving the critical section. This is to prevent
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343 this task placing an item into the queue due to an
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344 interrupt making space on the queue between critical
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345 sections (when there might be a higher priority task
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346 blocked on the queue that cannot run yet because the
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347 scheduler gets suspended). */
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348 if( pxQueue->uxMessagesWaiting == pxQueue->uxLength )
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350 /* We unblocked but there is no space in the queue,
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351 we probably timed out. */
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352 xReturn = errQUEUE_FULL;
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355 /* Before leaving the critical section we have to ensure
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356 exclusive access again. */
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358 prvLockQueue( pxQueue );
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360 taskEXIT_CRITICAL();
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364 /* If xReturn is errQUEUE_FULL then we unblocked when the queue
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365 was still full. Don't check it again now as it is possible that
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366 an interrupt has removed an item from the queue since we left the
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367 critical section and we don't want to write to the queue in case
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368 there is a task of higher priority blocked waiting for space to
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369 be available on the queue. If this is the case the higher priority
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370 task will execute when the scheduler is unsupended. */
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371 if( xReturn != errQUEUE_FULL )
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373 /* When we are here it is possible that we unblocked as space became
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374 available on the queue. It is also possible that an ISR posted to the
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375 queue since we left the critical section, so it may be that again there
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376 is no space. This would only happen if a task and ISR post onto the
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378 taskENTER_CRITICAL();
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380 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
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382 /* There is room in the queue, copy the data into the queue. */
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383 prvCopyQueueData( pxQueue, pvItemToQueue );
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386 /* Update the TxLock count so prvUnlockQueue knows to check for
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387 tasks waiting for data to become available in the queue. */
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388 ++( pxQueue->xTxLock );
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392 xReturn = errQUEUE_FULL;
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395 taskEXIT_CRITICAL();
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398 if( xReturn == errQUEUE_FULL )
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400 if( xTicksToWait > 0 )
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402 if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
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404 xReturn = queueERRONEOUS_UNBLOCK;
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409 while( xReturn == queueERRONEOUS_UNBLOCK );
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411 prvUnlockQueue( pxQueue );
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416 /*-----------------------------------------------------------*/
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418 signed portBASE_TYPE xQueueSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xTaskPreviouslyWoken )
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420 /* Similar to xQueueSend, except we don't block if there is no room in the
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421 queue. Also we don't directly wake a task that was blocked on a queue
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422 read, instead we return a flag to say whether a context switch is required
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423 or not (i.e. has a task with a higher priority than us been woken by this
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425 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
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427 prvCopyQueueData( pxQueue, pvItemToQueue );
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429 /* If the queue is locked we do not alter the event list. This will
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430 be done when the queue is unlocked later. */
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431 if( pxQueue->xTxLock == queueUNLOCKED )
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433 /* We only want to wake one task per ISR, so check that a task has
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434 not already been woken. */
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435 if( !xTaskPreviouslyWoken )
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437 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
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439 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
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441 /* The task waiting has a higher priority so record that a
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442 context switch is required. */
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450 /* Increment the lock count so the task that unlocks the queue
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451 knows that data was posted while it was locked. */
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452 ++( pxQueue->xTxLock );
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456 return xTaskPreviouslyWoken;
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458 /*-----------------------------------------------------------*/
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460 signed portBASE_TYPE xQueueReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait )
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462 signed portBASE_TYPE xReturn = pdTRUE;
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463 xTimeOutType xTimeOut;
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465 /* This function is very similar to xQueueSend(). See comments within
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466 xQueueSend() for a more detailed explanation.
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468 Make sure other tasks do not access the queue. */
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471 /* Capture the current time status for future reference. */
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472 vTaskSetTimeOutState( &xTimeOut );
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474 /* Make sure interrupts do not access the queue. */
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475 prvLockQueue( pxQueue );
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479 /* If there are no messages in the queue we may have to block. */
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480 if( prvIsQueueEmpty( pxQueue ) )
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482 /* There are no messages in the queue, do we want to block or just
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483 leave with nothing? */
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484 if( xTicksToWait > ( portTickType ) 0 )
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486 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );
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487 taskENTER_CRITICAL();
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489 prvUnlockQueue( pxQueue );
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490 if( !xTaskResumeAll() )
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495 if( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 )
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497 /* We unblocked but the queue is empty. We probably
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499 xReturn = errQUEUE_EMPTY;
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503 prvLockQueue( pxQueue );
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505 taskEXIT_CRITICAL();
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509 if( xReturn != errQUEUE_EMPTY )
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511 taskENTER_CRITICAL();
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513 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
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515 pxQueue->pcReadFrom += pxQueue->uxItemSize;
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516 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
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518 pxQueue->pcReadFrom = pxQueue->pcHead;
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520 --( pxQueue->uxMessagesWaiting );
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521 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
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523 /* Increment the lock count so prvUnlockQueue knows to check for
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524 tasks waiting for space to become available on the queue. */
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525 ++( pxQueue->xRxLock );
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530 xReturn = errQUEUE_EMPTY;
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533 taskEXIT_CRITICAL();
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536 if( xReturn == errQUEUE_EMPTY )
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538 if( xTicksToWait > 0 )
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540 if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
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542 xReturn = queueERRONEOUS_UNBLOCK;
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546 } while( xReturn == queueERRONEOUS_UNBLOCK );
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548 /* We no longer require exclusive access to the queue. */
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549 prvUnlockQueue( pxQueue );
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554 /*-----------------------------------------------------------*/
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556 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken )
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558 signed portBASE_TYPE xReturn;
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560 /* We cannot block from an ISR, so check there is data available. */
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561 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
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563 /* Copy the data from the queue. */
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564 pxQueue->pcReadFrom += pxQueue->uxItemSize;
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565 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
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567 pxQueue->pcReadFrom = pxQueue->pcHead;
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569 --( pxQueue->uxMessagesWaiting );
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570 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
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572 /* If the queue is locked we will not modify the event list. Instead
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573 we update the lock count so the task that unlocks the queue will know
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574 that an ISR has removed data while the queue was locked. */
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575 if( pxQueue->xRxLock == queueUNLOCKED )
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577 /* We only want to wake one task per ISR, so check that a task has
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578 not already been woken. */
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579 if( !( *pxTaskWoken ) )
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581 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
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583 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
585 /* The task waiting has a higher priority than us so
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586 force a context switch. */
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587 *pxTaskWoken = pdTRUE;
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594 /* Increment the lock count so the task that unlocks the queue
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595 knows that data was removed while it was locked. */
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596 ++( pxQueue->xRxLock );
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608 /*-----------------------------------------------------------*/
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610 unsigned portBASE_TYPE uxQueueMessagesWaiting( xQueueHandle pxQueue )
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612 unsigned portBASE_TYPE uxReturn;
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614 taskENTER_CRITICAL();
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615 uxReturn = pxQueue->uxMessagesWaiting;
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616 taskEXIT_CRITICAL();
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620 /*-----------------------------------------------------------*/
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622 void vQueueDelete( xQueueHandle pxQueue )
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624 vPortFree( pxQueue->pcHead );
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625 vPortFree( pxQueue );
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627 /*-----------------------------------------------------------*/
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629 static void prvUnlockQueue( xQueueHandle pxQueue )
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631 /* THIS FUNCTION MUST BE CALLED WITH THE SCHEDULER SUSPENDED. */
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633 /* The lock counts contains the number of extra data items placed or
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634 removed from the queue while the queue was locked. When a queue is
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635 locked items can be added or removed, but the event lists cannot be
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637 taskENTER_CRITICAL();
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639 --( pxQueue->xTxLock );
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641 /* See if data was added to the queue while it was locked. */
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642 if( pxQueue->xTxLock > queueUNLOCKED )
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644 pxQueue->xTxLock = queueUNLOCKED;
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646 /* Data was posted while the queue was locked. Are any tasks
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647 blocked waiting for data to become available? */
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648 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
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650 /* Tasks that are removed from the event list will get added to
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651 the pending ready list as the scheduler is still suspended. */
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652 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
\r
654 /* The task waiting has a higher priority so record that a
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655 context switch is required. */
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656 vTaskMissedYield();
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661 taskEXIT_CRITICAL();
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663 /* Do the same for the Rx lock. */
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664 taskENTER_CRITICAL();
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666 --( pxQueue->xRxLock );
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668 if( pxQueue->xRxLock > queueUNLOCKED )
\r
670 pxQueue->xRxLock = queueUNLOCKED;
\r
672 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
\r
674 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
676 vTaskMissedYield();
\r
681 taskEXIT_CRITICAL();
\r
683 /*-----------------------------------------------------------*/
\r
685 static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue )
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687 signed portBASE_TYPE xReturn;
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689 taskENTER_CRITICAL();
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690 xReturn = ( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 );
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691 taskEXIT_CRITICAL();
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695 /*-----------------------------------------------------------*/
\r
697 static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue )
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699 signed portBASE_TYPE xReturn;
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701 taskENTER_CRITICAL();
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702 xReturn = ( pxQueue->uxMessagesWaiting == pxQueue->uxLength );
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703 taskEXIT_CRITICAL();
\r
707 /*-----------------------------------------------------------*/
\r
709 #if configUSE_CO_ROUTINES == 1
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710 signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait )
\r
712 signed portBASE_TYPE xReturn;
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714 /* If the queue is already full we may have to block. A critical section
\r
715 is required to prevent an interrupt removing something from the queue
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716 between the check to see if the queue is full and blocking on the queue. */
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717 portDISABLE_INTERRUPTS();
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719 if( prvIsQueueFull( pxQueue ) )
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721 /* The queue is full - do we want to block or just leave without
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723 if( xTicksToWait > ( portTickType ) 0 )
\r
725 /* As this is called from a coroutine we cannot block directly, but
\r
726 return indicating that we need to block. */
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727 vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToSend ) );
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728 portENABLE_INTERRUPTS();
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729 return errQUEUE_BLOCKED;
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733 portENABLE_INTERRUPTS();
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734 return errQUEUE_FULL;
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738 portENABLE_INTERRUPTS();
\r
742 portDISABLE_INTERRUPTS();
\r
744 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
\r
746 /* There is room in the queue, copy the data into the queue. */
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747 prvCopyQueueData( pxQueue, pvItemToQueue );
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750 /* Were any co-routines waiting for data to become available? */
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751 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
\r
753 /* In this instance the co-routine could be placed directly
\r
754 into the ready list as we are within a critical section.
\r
755 Instead the same pending ready list mechansim is used as if
\r
756 the event were caused from within an interrupt. */
\r
757 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
\r
759 /* The co-routine waiting has a higher priority so record
\r
760 that a yield might be appropriate. */
\r
761 xReturn = errQUEUE_YIELD;
\r
767 xReturn = errQUEUE_FULL;
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770 portENABLE_INTERRUPTS();
\r
775 /*-----------------------------------------------------------*/
\r
777 #if configUSE_CO_ROUTINES == 1
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778 signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait )
\r
780 signed portBASE_TYPE xReturn;
\r
782 /* If the queue is already empty we may have to block. A critical section
\r
783 is required to prevent an interrupt adding something to the queue
\r
784 between the check to see if the queue is empty and blocking on the queue. */
\r
785 portDISABLE_INTERRUPTS();
\r
787 if( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 )
\r
789 /* There are no messages in the queue, do we want to block or just
\r
790 leave with nothing? */
\r
791 if( xTicksToWait > ( portTickType ) 0 )
\r
793 /* As this is a co-routine we cannot block directly, but return
\r
794 indicating that we need to block. */
\r
795 vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToReceive ) );
\r
796 portENABLE_INTERRUPTS();
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797 return errQUEUE_BLOCKED;
\r
801 portENABLE_INTERRUPTS();
\r
802 return errQUEUE_FULL;
\r
806 portENABLE_INTERRUPTS();
\r
810 portDISABLE_INTERRUPTS();
\r
812 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
\r
814 /* Data is available from the queue. */
\r
815 pxQueue->pcReadFrom += pxQueue->uxItemSize;
\r
816 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
\r
818 pxQueue->pcReadFrom = pxQueue->pcHead;
\r
820 --( pxQueue->uxMessagesWaiting );
\r
821 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
\r
825 /* Were any co-routines waiting for space to become available? */
\r
826 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
\r
828 /* In this instance the co-routine could be placed directly
\r
829 into the ready list as we are within a critical section.
\r
830 Instead the same pending ready list mechansim is used as if
\r
831 the event were caused from within an interrupt. */
\r
832 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
834 xReturn = errQUEUE_YIELD;
\r
843 portENABLE_INTERRUPTS();
\r
848 /*-----------------------------------------------------------*/
\r
852 #if configUSE_CO_ROUTINES == 1
\r
853 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken )
\r
855 /* Cannot block within an ISR so if there is no space on the queue then
\r
856 exit without doing anything. */
\r
857 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
\r
859 prvCopyQueueData( pxQueue, pvItemToQueue );
\r
861 /* We only want to wake one co-routine per ISR, so check that a
\r
862 co-routine has not already been woken. */
\r
863 if( !xCoRoutinePreviouslyWoken )
\r
865 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
\r
867 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
\r
875 return xCoRoutinePreviouslyWoken;
\r
878 /*-----------------------------------------------------------*/
\r
880 #if configUSE_CO_ROUTINES == 1
\r
881 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxCoRoutineWoken )
\r
883 signed portBASE_TYPE xReturn;
\r
885 /* We cannot block from an ISR, so check there is data available. If
\r
886 not then just leave without doing anything. */
\r
887 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
\r
889 /* Copy the data from the queue. */
\r
890 pxQueue->pcReadFrom += pxQueue->uxItemSize;
\r
891 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
\r
893 pxQueue->pcReadFrom = pxQueue->pcHead;
\r
895 --( pxQueue->uxMessagesWaiting );
\r
896 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
\r
898 if( !( *pxCoRoutineWoken ) )
\r
900 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
\r
902 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
904 *pxCoRoutineWoken = pdTRUE;
\r
919 /*-----------------------------------------------------------*/
\r