2 FreeRTOS.org V4.2.0 - Copyright (C) 2003-2007 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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68 Changes from V4.1.3:
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70 + Modified xQueueSend() and xQueueReceive() to handle the (very unlikely)
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71 case whereby a task unblocking due to a temporal event can remove/send an
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72 item from/to a queue when a higher priority task is still blocked on the
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73 queue. This modification is a result of the SafeRTOS testing.
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78 #include "FreeRTOS.h"
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80 #include "croutine.h"
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82 /*-----------------------------------------------------------
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83 * PUBLIC LIST API documented in list.h
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84 *----------------------------------------------------------*/
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86 /* Constants used with the cRxLock and cTxLock structure members. */
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87 #define queueUNLOCKED ( ( signed portBASE_TYPE ) -1 )
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88 #define queueERRONEOUS_UNBLOCK ( -1 )
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91 * Definition of the queue used by the scheduler.
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92 * Items are queued by copy, not reference.
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94 typedef struct QueueDefinition
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96 signed portCHAR *pcHead; /*< Points to the beginning of the queue storage area. */
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97 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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99 signed portCHAR *pcWriteTo; /*< Points to the free next place in the storage area. */
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100 signed portCHAR *pcReadFrom; /*< Points to the last place that a queued item was read from. */
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102 xList xTasksWaitingToSend; /*< List of tasks that are blocked waiting to post onto this queue. Stored in priority order. */
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103 xList xTasksWaitingToReceive; /*< List of tasks that are blocked waiting to read from this queue. Stored in priority order. */
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105 unsigned portBASE_TYPE uxMessagesWaiting;/*< The number of items currently in the queue. */
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106 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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107 unsigned portBASE_TYPE uxItemSize; /*< The size of each items that the queue will hold. */
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109 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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110 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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112 /*-----------------------------------------------------------*/
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115 * Inside this file xQueueHandle is a pointer to a xQUEUE structure.
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116 * To keep the definition private the API header file defines it as a
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119 typedef xQUEUE * xQueueHandle;
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122 * Prototypes for public functions are included here so we don't have to
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123 * include the API header file (as it defines xQueueHandle differently). These
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124 * functions are documented in the API header file.
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126 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize );
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127 signed portBASE_TYPE xQueueSend( xQueueHandle xQueue, const void * pvItemToQueue, portTickType xTicksToWait );
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128 unsigned portBASE_TYPE uxQueueMessagesWaiting( xQueueHandle pxQueue );
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129 void vQueueDelete( xQueueHandle xQueue );
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130 signed portBASE_TYPE xQueueSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xTaskPreviouslyWoken );
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131 signed portBASE_TYPE xQueueReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );
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132 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
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134 #if configUSE_CO_ROUTINES == 1
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135 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken );
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136 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
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137 signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait );
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138 signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );
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142 * Unlocks a queue locked by a call to prvLockQueue. Locking a queue does not
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143 * prevent an ISR from adding or removing items to the queue, but does prevent
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144 * an ISR from removing tasks from the queue event lists. If an ISR finds a
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145 * queue is locked it will instead increment the appropriate queue lock count
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146 * to indicate that a task may require unblocking. When the queue in unlocked
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147 * these lock counts are inspected, and the appropriate action taken.
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149 static void prvUnlockQueue( xQueueHandle pxQueue );
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152 * Uses a critical section to determine if there is any data in a queue.
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154 * @return pdTRUE if the queue contains no items, otherwise pdFALSE.
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156 static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue );
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159 * Uses a critical section to determine if there is any space in a queue.
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161 * @return pdTRUE if there is no space, otherwise pdFALSE;
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163 static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue );
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166 * Macro that copies an item into the queue. This is done by copying the item
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167 * byte for byte, not by reference. Updates the queue state to ensure it's
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168 * integrity after the copy.
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170 #define prvCopyQueueData( pxQueue, pvItemToQueue ) \
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172 memcpy( ( void * ) pxQueue->pcWriteTo, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize ); \
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173 ++( pxQueue->uxMessagesWaiting ); \
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174 pxQueue->pcWriteTo += pxQueue->uxItemSize; \
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175 if( pxQueue->pcWriteTo >= pxQueue->pcTail ) \
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177 pxQueue->pcWriteTo = pxQueue->pcHead; \
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180 /*-----------------------------------------------------------*/
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183 * Macro to mark a queue as locked. Locking a queue prevents an ISR from
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184 * accessing the queue event lists.
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186 #define prvLockQueue( pxQueue ) \
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188 taskENTER_CRITICAL(); \
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189 ++( pxQueue->xRxLock ); \
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190 ++( pxQueue->xTxLock ); \
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191 taskEXIT_CRITICAL(); \
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193 /*-----------------------------------------------------------*/
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196 /*-----------------------------------------------------------
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197 * PUBLIC QUEUE MANAGEMENT API documented in queue.h
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198 *----------------------------------------------------------*/
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200 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize )
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202 xQUEUE *pxNewQueue;
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203 size_t xQueueSizeInBytes;
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205 /* Allocate the new queue structure. */
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206 if( uxQueueLength > ( unsigned portBASE_TYPE ) 0 )
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208 pxNewQueue = ( xQUEUE * ) pvPortMalloc( sizeof( xQUEUE ) );
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209 if( pxNewQueue != NULL )
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211 /* Create the list of pointers to queue items. The queue is one byte
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212 longer than asked for to make wrap checking easier/faster. */
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213 xQueueSizeInBytes = ( size_t ) ( uxQueueLength * uxItemSize ) + ( size_t ) 1;
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215 pxNewQueue->pcHead = ( signed portCHAR * ) pvPortMalloc( xQueueSizeInBytes );
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216 if( pxNewQueue->pcHead != NULL )
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218 /* Initialise the queue members as described above where the
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219 queue type is defined. */
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220 pxNewQueue->pcTail = pxNewQueue->pcHead + ( uxQueueLength * uxItemSize );
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221 pxNewQueue->uxMessagesWaiting = 0;
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222 pxNewQueue->pcWriteTo = pxNewQueue->pcHead;
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223 pxNewQueue->pcReadFrom = pxNewQueue->pcHead + ( ( uxQueueLength - 1 ) * uxItemSize );
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224 pxNewQueue->uxLength = uxQueueLength;
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225 pxNewQueue->uxItemSize = uxItemSize;
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226 pxNewQueue->xRxLock = queueUNLOCKED;
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227 pxNewQueue->xTxLock = queueUNLOCKED;
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229 /* Likewise ensure the event queues start with the correct state. */
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230 vListInitialise( &( pxNewQueue->xTasksWaitingToSend ) );
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231 vListInitialise( &( pxNewQueue->xTasksWaitingToReceive ) );
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237 vPortFree( pxNewQueue );
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242 /* Will only reach here if we could not allocate enough memory or no memory
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246 /*-----------------------------------------------------------*/
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248 signed portBASE_TYPE xQueueSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait )
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250 signed portBASE_TYPE xReturn = pdPASS;
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251 xTimeOutType xTimeOut;
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253 /* Make sure other tasks do not access the queue. */
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256 /* Capture the current time status for future reference. */
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257 vTaskSetTimeOutState( &xTimeOut );
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259 /* It is important that this is the only thread/ISR that modifies the
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260 ready or delayed lists until xTaskResumeAll() is called. Places where
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261 the ready/delayed lists are modified include:
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263 + vTaskDelay() - Nothing can call vTaskDelay as the scheduler is
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264 suspended, vTaskDelay() cannot be called from an ISR.
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265 + vTaskPrioritySet() - Has a critical section around the access.
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266 + vTaskSwitchContext() - This will not get executed while the scheduler
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268 + prvCheckDelayedTasks() - This will not get executed while the
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269 scheduler is suspended.
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270 + xTaskCreate() - Has a critical section around the access.
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271 + vTaskResume() - Has a critical section around the access.
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272 + xTaskResumeAll() - Has a critical section around the access.
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273 + xTaskRemoveFromEventList - Checks to see if the scheduler is
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274 suspended. If so then the TCB being removed from the event is
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275 removed from the event and added to the xPendingReadyList.
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278 /* Make sure interrupts do not access the queue event list. */
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279 prvLockQueue( pxQueue );
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281 /* It is important that interrupts to not access the event list of the
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282 queue being modified here. Places where the event list is modified
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285 + xQueueSendFromISR(). This checks the lock on the queue to see if
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286 it has access. If the queue is locked then the Tx lock count is
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287 incremented to signify that a task waiting for data can be made ready
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288 once the queue lock is removed. If the queue is not locked then
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289 a task can be moved from the event list, but will not be removed
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290 from the delayed list or placed in the ready list until the scheduler
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293 + xQueueReceiveFromISR(). As per xQueueSendFromISR().
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296 /* If the queue is already full we may have to block. */
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299 if( prvIsQueueFull( pxQueue ) )
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301 /* The queue is full - do we want to block or just leave without
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303 if( xTicksToWait > ( portTickType ) 0 )
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305 /* We are going to place ourselves on the xTasksWaitingToSend event
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306 list, and will get woken should the delay expire, or space become
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307 available on the queue.
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309 As detailed above we do not require mutual exclusion on the event
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310 list as nothing else can modify it or the ready lists while we
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311 have the scheduler suspended and queue locked.
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313 It is possible that an ISR has removed data from the queue since we
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314 checked if any was available. If this is the case then the data
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315 will have been copied from the queue, and the queue variables
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316 updated, but the event list will not yet have been checked to see if
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317 anything is waiting as the queue is locked. */
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318 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );
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320 /* Force a context switch now as we are blocked. We can do
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321 this from within a critical section as the task we are
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322 switching to has its own context. When we return here (i.e. we
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323 unblock) we will leave the critical section as normal.
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325 It is possible that an ISR has caused an event on an unrelated and
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326 unlocked queue. If this was the case then the event list for that
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327 queue will have been updated but the ready lists left unchanged -
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328 instead the readied task will have been added to the pending ready
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330 taskENTER_CRITICAL();
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332 /* We can safely unlock the queue and scheduler here as
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333 interrupts are disabled. We must not yield with anything
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334 locked, but we can yield from within a critical section.
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336 Tasks that have been placed on the pending ready list cannot
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337 be tasks that are waiting for events on this queue. See
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338 in comment xTaskRemoveFromEventList(). */
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339 prvUnlockQueue( pxQueue );
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341 /* Resuming the scheduler may cause a yield. If so then there
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342 is no point yielding again here. */
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343 if( !xTaskResumeAll() )
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348 /* We want to check to see if the queue is still full
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349 before leaving the critical section. This is to prevent
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350 this task placing an item into the queue due to an
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351 interrupt making space on the queue between critical
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352 sections (when there might be a higher priority task
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353 blocked on the queue that cannot run yet because the
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354 scheduler gets suspended). */
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355 if( pxQueue->uxMessagesWaiting == pxQueue->uxLength )
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357 /* We unblocked but there is no space in the queue,
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358 we probably timed out. */
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359 xReturn = errQUEUE_FULL;
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362 /* Before leaving the critical section we have to ensure
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363 exclusive access again. */
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365 prvLockQueue( pxQueue );
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367 taskEXIT_CRITICAL();
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371 /* If xReturn is errQUEUE_FULL then we unblocked when the queue
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372 was still full. Don't check it again now as it is possible that
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373 an interrupt has removed an item from the queue since we left the
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374 critical section and we don't want to write to the queue in case
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375 there is a task of higher priority blocked waiting for space to
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376 be available on the queue. If this is the case the higher priority
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377 task will execute when the scheduler is unsupended. */
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378 if( xReturn != errQUEUE_FULL )
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380 /* When we are here it is possible that we unblocked as space became
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381 available on the queue. It is also possible that an ISR posted to the
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382 queue since we left the critical section, so it may be that again there
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383 is no space. This would only happen if a task and ISR post onto the
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385 taskENTER_CRITICAL();
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387 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
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389 /* There is room in the queue, copy the data into the queue. */
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390 prvCopyQueueData( pxQueue, pvItemToQueue );
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393 /* Update the TxLock count so prvUnlockQueue knows to check for
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394 tasks waiting for data to become available in the queue. */
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395 ++( pxQueue->xTxLock );
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399 xReturn = errQUEUE_FULL;
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402 taskEXIT_CRITICAL();
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405 if( xReturn == errQUEUE_FULL )
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407 if( xTicksToWait > 0 )
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409 if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
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411 xReturn = queueERRONEOUS_UNBLOCK;
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416 while( xReturn == queueERRONEOUS_UNBLOCK );
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418 prvUnlockQueue( pxQueue );
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423 /*-----------------------------------------------------------*/
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425 signed portBASE_TYPE xQueueSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xTaskPreviouslyWoken )
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427 /* Similar to xQueueSend, except we don't block if there is no room in the
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428 queue. Also we don't directly wake a task that was blocked on a queue
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429 read, instead we return a flag to say whether a context switch is required
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430 or not (i.e. has a task with a higher priority than us been woken by this
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432 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
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434 prvCopyQueueData( pxQueue, pvItemToQueue );
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436 /* If the queue is locked we do not alter the event list. This will
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437 be done when the queue is unlocked later. */
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438 if( pxQueue->xTxLock == queueUNLOCKED )
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440 /* We only want to wake one task per ISR, so check that a task has
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441 not already been woken. */
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442 if( !xTaskPreviouslyWoken )
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444 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
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446 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
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448 /* The task waiting has a higher priority so record that a
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449 context switch is required. */
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457 /* Increment the lock count so the task that unlocks the queue
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458 knows that data was posted while it was locked. */
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459 ++( pxQueue->xTxLock );
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463 return xTaskPreviouslyWoken;
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465 /*-----------------------------------------------------------*/
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467 signed portBASE_TYPE xQueueReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait )
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469 signed portBASE_TYPE xReturn = pdTRUE;
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470 xTimeOutType xTimeOut;
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472 /* This function is very similar to xQueueSend(). See comments within
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473 xQueueSend() for a more detailed explanation.
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475 Make sure other tasks do not access the queue. */
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478 /* Capture the current time status for future reference. */
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479 vTaskSetTimeOutState( &xTimeOut );
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481 /* Make sure interrupts do not access the queue. */
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482 prvLockQueue( pxQueue );
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486 /* If there are no messages in the queue we may have to block. */
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487 if( prvIsQueueEmpty( pxQueue ) )
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489 /* There are no messages in the queue, do we want to block or just
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490 leave with nothing? */
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491 if( xTicksToWait > ( portTickType ) 0 )
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493 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );
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494 taskENTER_CRITICAL();
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496 prvUnlockQueue( pxQueue );
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497 if( !xTaskResumeAll() )
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502 if( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 )
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504 /* We unblocked but the queue is empty. We probably
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506 xReturn = errQUEUE_EMPTY;
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510 prvLockQueue( pxQueue );
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512 taskEXIT_CRITICAL();
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516 if( xReturn != errQUEUE_EMPTY )
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518 taskENTER_CRITICAL();
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520 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
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522 pxQueue->pcReadFrom += pxQueue->uxItemSize;
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523 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
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525 pxQueue->pcReadFrom = pxQueue->pcHead;
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527 --( pxQueue->uxMessagesWaiting );
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528 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
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530 /* Increment the lock count so prvUnlockQueue knows to check for
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531 tasks waiting for space to become available on the queue. */
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532 ++( pxQueue->xRxLock );
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537 xReturn = errQUEUE_EMPTY;
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540 taskEXIT_CRITICAL();
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543 if( xReturn == errQUEUE_EMPTY )
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545 if( xTicksToWait > 0 )
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547 if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
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549 xReturn = queueERRONEOUS_UNBLOCK;
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553 } while( xReturn == queueERRONEOUS_UNBLOCK );
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555 /* We no longer require exclusive access to the queue. */
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556 prvUnlockQueue( pxQueue );
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561 /*-----------------------------------------------------------*/
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563 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken )
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565 signed portBASE_TYPE xReturn;
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567 /* We cannot block from an ISR, so check there is data available. */
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568 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
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570 /* Copy the data from the queue. */
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571 pxQueue->pcReadFrom += pxQueue->uxItemSize;
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572 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
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574 pxQueue->pcReadFrom = pxQueue->pcHead;
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576 --( pxQueue->uxMessagesWaiting );
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577 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
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579 /* If the queue is locked we will not modify the event list. Instead
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580 we update the lock count so the task that unlocks the queue will know
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581 that an ISR has removed data while the queue was locked. */
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582 if( pxQueue->xRxLock == queueUNLOCKED )
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584 /* We only want to wake one task per ISR, so check that a task has
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585 not already been woken. */
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586 if( !( *pxTaskWoken ) )
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588 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
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590 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
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592 /* The task waiting has a higher priority than us so
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593 force a context switch. */
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594 *pxTaskWoken = pdTRUE;
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601 /* Increment the lock count so the task that unlocks the queue
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602 knows that data was removed while it was locked. */
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603 ++( pxQueue->xRxLock );
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615 /*-----------------------------------------------------------*/
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617 unsigned portBASE_TYPE uxQueueMessagesWaiting( xQueueHandle pxQueue )
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619 unsigned portBASE_TYPE uxReturn;
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621 taskENTER_CRITICAL();
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622 uxReturn = pxQueue->uxMessagesWaiting;
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623 taskEXIT_CRITICAL();
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627 /*-----------------------------------------------------------*/
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629 void vQueueDelete( xQueueHandle pxQueue )
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631 vPortFree( pxQueue->pcHead );
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632 vPortFree( pxQueue );
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634 /*-----------------------------------------------------------*/
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636 static void prvUnlockQueue( xQueueHandle pxQueue )
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638 /* THIS FUNCTION MUST BE CALLED WITH THE SCHEDULER SUSPENDED. */
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640 /* The lock counts contains the number of extra data items placed or
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641 removed from the queue while the queue was locked. When a queue is
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642 locked items can be added or removed, but the event lists cannot be
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644 taskENTER_CRITICAL();
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646 --( pxQueue->xTxLock );
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648 /* See if data was added to the queue while it was locked. */
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649 if( pxQueue->xTxLock > queueUNLOCKED )
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651 pxQueue->xTxLock = queueUNLOCKED;
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653 /* Data was posted while the queue was locked. Are any tasks
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654 blocked waiting for data to become available? */
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655 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
\r
657 /* Tasks that are removed from the event list will get added to
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658 the pending ready list as the scheduler is still suspended. */
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659 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
\r
661 /* The task waiting has a higher priority so record that a
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662 context switch is required. */
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663 vTaskMissedYield();
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668 taskEXIT_CRITICAL();
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670 /* Do the same for the Rx lock. */
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671 taskENTER_CRITICAL();
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673 --( pxQueue->xRxLock );
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675 if( pxQueue->xRxLock > queueUNLOCKED )
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677 pxQueue->xRxLock = queueUNLOCKED;
\r
679 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
\r
681 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
683 vTaskMissedYield();
\r
688 taskEXIT_CRITICAL();
\r
690 /*-----------------------------------------------------------*/
\r
692 static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue )
\r
694 signed portBASE_TYPE xReturn;
\r
696 taskENTER_CRITICAL();
\r
697 xReturn = ( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 );
\r
698 taskEXIT_CRITICAL();
\r
702 /*-----------------------------------------------------------*/
\r
704 static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue )
\r
706 signed portBASE_TYPE xReturn;
\r
708 taskENTER_CRITICAL();
\r
709 xReturn = ( pxQueue->uxMessagesWaiting == pxQueue->uxLength );
\r
710 taskEXIT_CRITICAL();
\r
714 /*-----------------------------------------------------------*/
\r
716 #if configUSE_CO_ROUTINES == 1
\r
717 signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait )
\r
719 signed portBASE_TYPE xReturn;
\r
721 /* If the queue is already full we may have to block. A critical section
\r
722 is required to prevent an interrupt removing something from the queue
\r
723 between the check to see if the queue is full and blocking on the queue. */
\r
724 portDISABLE_INTERRUPTS();
\r
726 if( prvIsQueueFull( pxQueue ) )
\r
728 /* The queue is full - do we want to block or just leave without
\r
730 if( xTicksToWait > ( portTickType ) 0 )
\r
732 /* As this is called from a coroutine we cannot block directly, but
\r
733 return indicating that we need to block. */
\r
734 vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToSend ) );
\r
735 portENABLE_INTERRUPTS();
\r
736 return errQUEUE_BLOCKED;
\r
740 portENABLE_INTERRUPTS();
\r
741 return errQUEUE_FULL;
\r
745 portENABLE_INTERRUPTS();
\r
749 portDISABLE_INTERRUPTS();
\r
751 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
\r
753 /* There is room in the queue, copy the data into the queue. */
\r
754 prvCopyQueueData( pxQueue, pvItemToQueue );
\r
757 /* Were any co-routines waiting for data to become available? */
\r
758 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
\r
760 /* In this instance the co-routine could be placed directly
\r
761 into the ready list as we are within a critical section.
\r
762 Instead the same pending ready list mechansim is used as if
\r
763 the event were caused from within an interrupt. */
\r
764 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
\r
766 /* The co-routine waiting has a higher priority so record
\r
767 that a yield might be appropriate. */
\r
768 xReturn = errQUEUE_YIELD;
\r
774 xReturn = errQUEUE_FULL;
\r
777 portENABLE_INTERRUPTS();
\r
782 /*-----------------------------------------------------------*/
\r
784 #if configUSE_CO_ROUTINES == 1
\r
785 signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait )
\r
787 signed portBASE_TYPE xReturn;
\r
789 /* If the queue is already empty we may have to block. A critical section
\r
790 is required to prevent an interrupt adding something to the queue
\r
791 between the check to see if the queue is empty and blocking on the queue. */
\r
792 portDISABLE_INTERRUPTS();
\r
794 if( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 )
\r
796 /* There are no messages in the queue, do we want to block or just
\r
797 leave with nothing? */
\r
798 if( xTicksToWait > ( portTickType ) 0 )
\r
800 /* As this is a co-routine we cannot block directly, but return
\r
801 indicating that we need to block. */
\r
802 vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToReceive ) );
\r
803 portENABLE_INTERRUPTS();
\r
804 return errQUEUE_BLOCKED;
\r
808 portENABLE_INTERRUPTS();
\r
809 return errQUEUE_FULL;
\r
813 portENABLE_INTERRUPTS();
\r
817 portDISABLE_INTERRUPTS();
\r
819 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
\r
821 /* Data is available from the queue. */
\r
822 pxQueue->pcReadFrom += pxQueue->uxItemSize;
\r
823 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
\r
825 pxQueue->pcReadFrom = pxQueue->pcHead;
\r
827 --( pxQueue->uxMessagesWaiting );
\r
828 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
\r
832 /* Were any co-routines waiting for space to become available? */
\r
833 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
\r
835 /* In this instance the co-routine could be placed directly
\r
836 into the ready list as we are within a critical section.
\r
837 Instead the same pending ready list mechansim is used as if
\r
838 the event were caused from within an interrupt. */
\r
839 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
841 xReturn = errQUEUE_YIELD;
\r
850 portENABLE_INTERRUPTS();
\r
855 /*-----------------------------------------------------------*/
\r
859 #if configUSE_CO_ROUTINES == 1
\r
860 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken )
\r
862 /* Cannot block within an ISR so if there is no space on the queue then
\r
863 exit without doing anything. */
\r
864 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
\r
866 prvCopyQueueData( pxQueue, pvItemToQueue );
\r
868 /* We only want to wake one co-routine per ISR, so check that a
\r
869 co-routine has not already been woken. */
\r
870 if( !xCoRoutinePreviouslyWoken )
\r
872 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
\r
874 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
\r
882 return xCoRoutinePreviouslyWoken;
\r
885 /*-----------------------------------------------------------*/
\r
887 #if configUSE_CO_ROUTINES == 1
\r
888 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxCoRoutineWoken )
\r
890 signed portBASE_TYPE xReturn;
\r
892 /* We cannot block from an ISR, so check there is data available. If
\r
893 not then just leave without doing anything. */
\r
894 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
\r
896 /* Copy the data from the queue. */
\r
897 pxQueue->pcReadFrom += pxQueue->uxItemSize;
\r
898 if( pxQueue->pcReadFrom >= pxQueue->pcTail )
\r
900 pxQueue->pcReadFrom = pxQueue->pcHead;
\r
902 --( pxQueue->uxMessagesWaiting );
\r
903 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
\r
905 if( !( *pxCoRoutineWoken ) )
\r
907 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
\r
909 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
\r
911 *pxCoRoutineWoken = pdTRUE;
\r
926 /*-----------------------------------------------------------*/
\r