]> git.sur5r.net Git - freertos/blobdiff - FreeRTOS/Source/queue.c
Update to MIT licensed FreeRTOS V10.0.0 - see https://www.freertos.org/History.txt
[freertos] / FreeRTOS / Source / queue.c
index 824c263e1dd5db278598c916d24060085c7b206c..e151f81fc8424082708ff7d0fea21fbaa62ca3cd 100644 (file)
@@ -1,71 +1,30 @@
 /*\r
-    FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.\r
-    All rights reserved\r
-\r
-    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.\r
-\r
-    This file is part of the FreeRTOS distribution.\r
-\r
-    FreeRTOS is free software; you can redistribute it and/or modify it under\r
-    the terms of the GNU General Public License (version 2) as published by the\r
-    Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.\r
-\r
-    ***************************************************************************\r
-    >>!   NOTE: The modification to the GPL is included to allow you to     !<<\r
-    >>!   distribute a combined work that includes FreeRTOS without being   !<<\r
-    >>!   obliged to provide the source code for proprietary components     !<<\r
-    >>!   outside of the FreeRTOS kernel.                                   !<<\r
-    ***************************************************************************\r
-\r
-    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY\r
-    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS\r
-    FOR A PARTICULAR PURPOSE.  Full license text is available on the following\r
-    link: http://www.freertos.org/a00114.html\r
-\r
-    ***************************************************************************\r
-     *                                                                       *\r
-     *    FreeRTOS provides completely free yet professionally developed,    *\r
-     *    robust, strictly quality controlled, supported, and cross          *\r
-     *    platform software that is more than just the market leader, it     *\r
-     *    is the industry's de facto standard.                               *\r
-     *                                                                       *\r
-     *    Help yourself get started quickly while simultaneously helping     *\r
-     *    to support the FreeRTOS project by purchasing a FreeRTOS           *\r
-     *    tutorial book, reference manual, or both:                          *\r
-     *    http://www.FreeRTOS.org/Documentation                              *\r
-     *                                                                       *\r
-    ***************************************************************************\r
-\r
-    http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading\r
-    the FAQ page "My application does not run, what could be wrong?".  Have you\r
-    defined configASSERT()?\r
-\r
-    http://www.FreeRTOS.org/support - In return for receiving this top quality\r
-    embedded software for free we request you assist our global community by\r
-    participating in the support forum.\r
-\r
-    http://www.FreeRTOS.org/training - Investing in training allows your team to\r
-    be as productive as possible as early as possible.  Now you can receive\r
-    FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers\r
-    Ltd, and the world's leading authority on the world's leading RTOS.\r
-\r
-    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,\r
-    including FreeRTOS+Trace - an indispensable productivity tool, a DOS\r
-    compatible FAT file system, and our tiny thread aware UDP/IP stack.\r
-\r
-    http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.\r
-    Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.\r
-\r
-    http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High\r
-    Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS\r
-    licenses offer ticketed support, indemnification and commercial middleware.\r
-\r
-    http://www.SafeRTOS.com - High Integrity Systems also provide a safety\r
-    engineered and independently SIL3 certified version for use in safety and\r
-    mission critical applications that require provable dependability.\r
-\r
-    1 tab == 4 spaces!\r
-*/\r
+ * FreeRTOS Kernel V10.0.0\r
+ * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.\r
+ *\r
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of\r
+ * this software and associated documentation files (the "Software"), to deal in\r
+ * the Software without restriction, including without limitation the rights to\r
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of\r
+ * the Software, and to permit persons to whom the Software is furnished to do so,\r
+ * subject to the following conditions:\r
+ *\r
+ * The above copyright notice and this permission notice shall be included in all\r
+ * copies or substantial portions of the Software. If you wish to use our Amazon\r
+ * FreeRTOS name, please do so in a fair use way that does not cause confusion.\r
+ *\r
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\r
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS\r
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR\r
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER\r
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN\r
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
+ *\r
+ * http://www.FreeRTOS.org\r
+ * http://aws.amazon.com/freertos\r
+ *\r
+ * 1 tab == 4 spaces!\r
+ */\r
 \r
 #include <stdlib.h>\r
 #include <string.h>\r
@@ -255,6 +214,16 @@ static void prvInitialiseNewQueue( const UBaseType_t uxQueueLength, const UBaseT
        static void prvInitialiseMutex( Queue_t *pxNewQueue ) PRIVILEGED_FUNCTION;\r
 #endif\r
 \r
+#if( configUSE_MUTEXES == 1 )\r
+       /*\r
+        * If a task waiting for a mutex causes the mutex holder to inherit a\r
+        * priority, but the waiting task times out, then the holder should\r
+        * disinherit the priority - but only down to the highest priority of any\r
+        * other tasks that are waiting for the same mutex.  This function returns\r
+        * that priority.\r
+        */\r
+       static UBaseType_t prvGetDisinheritPriorityAfterTimeout( const Queue_t * const pxQueue ) PRIVILEGED_FUNCTION;\r
+#endif\r
 /*-----------------------------------------------------------*/\r
 \r
 /*\r
@@ -374,6 +343,10 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
 \r
                        prvInitialiseNewQueue( uxQueueLength, uxItemSize, pucQueueStorage, ucQueueType, pxNewQueue );\r
                }\r
+               else\r
+               {\r
+                       traceQUEUE_CREATE_FAILED( ucQueueType );\r
+               }\r
 \r
                return pxNewQueue;\r
        }\r
@@ -422,6 +395,10 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
 \r
                        prvInitialiseNewQueue( uxQueueLength, uxItemSize, pucQueueStorage, ucQueueType, pxNewQueue );\r
                }\r
+               else\r
+               {\r
+                       traceQUEUE_CREATE_FAILED( ucQueueType );\r
+               }\r
 \r
                return pxNewQueue;\r
        }\r
@@ -669,7 +646,7 @@ static void prvInitialiseNewQueue( const UBaseType_t uxQueueLength, const UBaseT
                }\r
                else\r
                {\r
-                       xReturn = xQueueGenericReceive( pxMutex, NULL, xTicksToWait, pdFALSE );\r
+                       xReturn = xQueueSemaphoreTake( pxMutex, xTicksToWait );\r
 \r
                        /* pdPASS will only be returned if the mutex was successfully\r
                        obtained.  The calling task may have entered the Blocked state\r
@@ -881,7 +858,7 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                                {\r
                                        /* The queue was full and a block time was specified so\r
                                        configure the timeout structure. */\r
-                                       vTaskSetTimeOutState( &xTimeOut );\r
+                                       vTaskInternalSetTimeOutState( &xTimeOut );\r
                                        xEntryTimeSet = pdTRUE;\r
                                }\r
                                else\r
@@ -908,8 +885,8 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                                vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );\r
 \r
                                /* Unlocking the queue means queue events can effect the\r
-                               event list.  It is possible     that interrupts occurring now\r
-                               remove this task from the event list again - but as the\r
+                               event list.  It is possible that interrupts occurring now\r
+                               remove this task from the event list again - but as the\r
                                scheduler is suspended the task will go onto the pending\r
                                ready last instead of the actual ready list. */\r
                                prvUnlockQueue( pxQueue );\r
@@ -1260,21 +1237,27 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
 }\r
 /*-----------------------------------------------------------*/\r
 \r
-BaseType_t xQueueGenericReceive( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait, const BaseType_t xJustPeeking )\r
+BaseType_t xQueueReceive( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait )\r
 {\r
 BaseType_t xEntryTimeSet = pdFALSE;\r
 TimeOut_t xTimeOut;\r
-int8_t *pcOriginalReadPosition;\r
 Queue_t * const pxQueue = ( Queue_t * ) xQueue;\r
 \r
-       configASSERT( pxQueue );\r
-       configASSERT( !( ( pvBuffer == NULL ) && ( pxQueue->uxItemSize != ( UBaseType_t ) 0U ) ) );\r
+       /* Check the pointer is not NULL. */\r
+       configASSERT( ( pxQueue ) );\r
+\r
+       /* The buffer into which data is received can only be NULL if the data size\r
+       is zero (so no data is copied into the buffer. */\r
+       configASSERT( !( ( ( pvBuffer ) == NULL ) && ( ( pxQueue )->uxItemSize != ( UBaseType_t ) 0U ) ) );\r
+\r
+       /* Cannot block if the scheduler is suspended. */\r
        #if ( ( INCLUDE_xTaskGetSchedulerState == 1 ) || ( configUSE_TIMERS == 1 ) )\r
        {\r
                configASSERT( !( ( xTaskGetSchedulerState() == taskSCHEDULER_SUSPENDED ) && ( xTicksToWait != 0 ) ) );\r
        }\r
        #endif\r
 \r
+\r
        /* This function relaxes the coding standard somewhat to allow return\r
        statements within the function itself.  This is done in the interest\r
        of execution time efficiency. */\r
@@ -1289,44 +1272,19 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                        must be the highest priority task wanting to access the queue. */\r
                        if( uxMessagesWaiting > ( UBaseType_t ) 0 )\r
                        {\r
-                               /* Remember the read position in case the queue is only being\r
-                               peeked. */\r
-                               pcOriginalReadPosition = pxQueue->u.pcReadFrom;\r
-\r
+                               /* Data available, remove one item. */\r
                                prvCopyDataFromQueue( pxQueue, pvBuffer );\r
+                               traceQUEUE_RECEIVE( pxQueue );\r
+                               pxQueue->uxMessagesWaiting = uxMessagesWaiting - ( UBaseType_t ) 1;\r
 \r
-                               if( xJustPeeking == pdFALSE )\r
+                               /* There is now space in the queue, were any tasks waiting to\r
+                               post to the queue?  If so, unblock the highest priority waiting\r
+                               task. */\r
+                               if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) == pdFALSE )\r
                                {\r
-                                       traceQUEUE_RECEIVE( pxQueue );\r
-\r
-                                       /* Actually removing data, not just peeking. */\r
-                                       pxQueue->uxMessagesWaiting = uxMessagesWaiting - ( UBaseType_t ) 1;\r
-\r
-                                       #if ( configUSE_MUTEXES == 1 )\r
-                                       {\r
-                                               if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
-                                               {\r
-                                                       /* Record the information required to implement\r
-                                                       priority inheritance should it become necessary. */\r
-                                                       pxQueue->pxMutexHolder = ( int8_t * ) pvTaskIncrementMutexHeldCount(); /*lint !e961 Cast is not redundant as TaskHandle_t is a typedef. */\r
-                                               }\r
-                                               else\r
-                                               {\r
-                                                       mtCOVERAGE_TEST_MARKER();\r
-                                               }\r
-                                       }\r
-                                       #endif /* configUSE_MUTEXES */\r
-\r
-                                       if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) == pdFALSE )\r
+                                       if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
                                        {\r
-                                               if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
-                                               {\r
-                                                       queueYIELD_IF_USING_PREEMPTION();\r
-                                               }\r
-                                               else\r
-                                               {\r
-                                                       mtCOVERAGE_TEST_MARKER();\r
-                                               }\r
+                                               queueYIELD_IF_USING_PREEMPTION();\r
                                        }\r
                                        else\r
                                        {\r
@@ -1335,31 +1293,171 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                                }\r
                                else\r
                                {\r
-                                       traceQUEUE_PEEK( pxQueue );\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
+\r
+                               taskEXIT_CRITICAL();\r
+                               return pdPASS;\r
+                       }\r
+                       else\r
+                       {\r
+                               if( xTicksToWait == ( TickType_t ) 0 )\r
+                               {\r
+                                       /* The queue was empty and no block time is specified (or\r
+                                       the block time has expired) so leave now. */\r
+                                       taskEXIT_CRITICAL();\r
+                                       traceQUEUE_RECEIVE_FAILED( pxQueue );\r
+                                       return errQUEUE_EMPTY;\r
+                               }\r
+                               else if( xEntryTimeSet == pdFALSE )\r
+                               {\r
+                                       /* The queue was empty and a block time was specified so\r
+                                       configure the timeout structure. */\r
+                                       vTaskInternalSetTimeOutState( &xTimeOut );\r
+                                       xEntryTimeSet = pdTRUE;\r
+                               }\r
+                               else\r
+                               {\r
+                                       /* Entry time was already set. */\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
+                       }\r
+               }\r
+               taskEXIT_CRITICAL();\r
 \r
-                                       /* The data is not being removed, so reset the read\r
-                                       pointer. */\r
-                                       pxQueue->u.pcReadFrom = pcOriginalReadPosition;\r
+               /* Interrupts and other tasks can send to and receive from the queue\r
+               now the critical section has been exited. */\r
 \r
-                                       /* The data is being left in the queue, so see if there are\r
-                                       any other tasks waiting for the data. */\r
-                                       if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) == pdFALSE )\r
+               vTaskSuspendAll();\r
+               prvLockQueue( pxQueue );\r
+\r
+               /* Update the timeout state to see if it has expired yet. */\r
+               if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
+               {\r
+                       /* The timeout has not expired.  If the queue is still empty place\r
+                       the task on the list of tasks waiting to receive from the queue. */\r
+                       if( prvIsQueueEmpty( pxQueue ) != pdFALSE )\r
+                       {\r
+                               traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );\r
+                               vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );\r
+                               prvUnlockQueue( pxQueue );\r
+                               if( xTaskResumeAll() == pdFALSE )\r
+                               {\r
+                                       portYIELD_WITHIN_API();\r
+                               }\r
+                               else\r
+                               {\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
+                       }\r
+                       else\r
+                       {\r
+                               /* The queue contains data again.  Loop back to try and read the\r
+                               data. */\r
+                               prvUnlockQueue( pxQueue );\r
+                               ( void ) xTaskResumeAll();\r
+                       }\r
+               }\r
+               else\r
+               {\r
+                       /* Timed out.  If there is no data in the queue exit, otherwise loop\r
+                       back and attempt to read the data. */\r
+                       prvUnlockQueue( pxQueue );\r
+                       ( void ) xTaskResumeAll();\r
+\r
+                       if( prvIsQueueEmpty( pxQueue ) != pdFALSE )\r
+                       {\r
+                               traceQUEUE_RECEIVE_FAILED( pxQueue );\r
+                               return errQUEUE_EMPTY;\r
+                       }\r
+                       else\r
+                       {\r
+                               mtCOVERAGE_TEST_MARKER();\r
+                       }\r
+               }\r
+       }\r
+}\r
+/*-----------------------------------------------------------*/\r
+\r
+BaseType_t xQueueSemaphoreTake( QueueHandle_t xQueue, TickType_t xTicksToWait )\r
+{\r
+BaseType_t xEntryTimeSet = pdFALSE;\r
+TimeOut_t xTimeOut;\r
+Queue_t * const pxQueue = ( Queue_t * ) xQueue;\r
+\r
+#if( configUSE_MUTEXES == 1 )\r
+       BaseType_t xInheritanceOccurred = pdFALSE;\r
+#endif\r
+\r
+       /* Check the queue pointer is not NULL. */\r
+       configASSERT( ( pxQueue ) );\r
+\r
+       /* Check this really is a semaphore, in which case the item size will be\r
+       0. */\r
+       configASSERT( pxQueue->uxItemSize == 0 );\r
+\r
+       /* Cannot block if the scheduler is suspended. */\r
+       #if ( ( INCLUDE_xTaskGetSchedulerState == 1 ) || ( configUSE_TIMERS == 1 ) )\r
+       {\r
+               configASSERT( !( ( xTaskGetSchedulerState() == taskSCHEDULER_SUSPENDED ) && ( xTicksToWait != 0 ) ) );\r
+       }\r
+       #endif\r
+\r
+\r
+       /* This function relaxes the coding standard somewhat to allow return\r
+       statements within the function itself.  This is done in the interest\r
+       of execution time efficiency. */\r
+\r
+       for( ;; )\r
+       {\r
+               taskENTER_CRITICAL();\r
+               {\r
+                       /* Semaphores are queues with an item size of 0, and where the\r
+                       number of messages in the queue is the semaphore's count value. */\r
+                       const UBaseType_t uxSemaphoreCount = pxQueue->uxMessagesWaiting;\r
+\r
+                       /* Is there data in the queue now?  To be running the calling task\r
+                       must be the highest priority task wanting to access the queue. */\r
+                       if( uxSemaphoreCount > ( UBaseType_t ) 0 )\r
+                       {\r
+                               traceQUEUE_RECEIVE( pxQueue );\r
+\r
+                               /* Semaphores are queues with a data size of zero and where the\r
+                               messages waiting is the semaphore's count.  Reduce the count. */\r
+                               pxQueue->uxMessagesWaiting = uxSemaphoreCount - ( UBaseType_t ) 1;\r
+\r
+                               #if ( configUSE_MUTEXES == 1 )\r
+                               {\r
+                                       if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
                                        {\r
-                                               if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
-                                               {\r
-                                                       /* The task waiting has a higher priority than this task. */\r
-                                                       queueYIELD_IF_USING_PREEMPTION();\r
-                                               }\r
-                                               else\r
-                                               {\r
-                                                       mtCOVERAGE_TEST_MARKER();\r
-                                               }\r
+                                               /* Record the information required to implement\r
+                                               priority inheritance should it become necessary. */\r
+                                               pxQueue->pxMutexHolder = ( int8_t * ) pvTaskIncrementMutexHeldCount(); /*lint !e961 Cast is not redundant as TaskHandle_t is a typedef. */\r
+                                       }\r
+                                       else\r
+                                       {\r
+                                               mtCOVERAGE_TEST_MARKER();\r
+                                       }\r
+                               }\r
+                               #endif /* configUSE_MUTEXES */\r
+\r
+                               /* Check to see if other tasks are blocked waiting to give the\r
+                               semaphore, and if so, unblock the highest priority such task. */\r
+                               if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) == pdFALSE )\r
+                               {\r
+                                       if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
+                                       {\r
+                                               queueYIELD_IF_USING_PREEMPTION();\r
                                        }\r
                                        else\r
                                        {\r
                                                mtCOVERAGE_TEST_MARKER();\r
                                        }\r
                                }\r
+                               else\r
+                               {\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
 \r
                                taskEXIT_CRITICAL();\r
                                return pdPASS;\r
@@ -1368,17 +1466,26 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                        {\r
                                if( xTicksToWait == ( TickType_t ) 0 )\r
                                {\r
-                                       /* The queue was empty and no block time is specified (or\r
-                                       the block time has expired) so leave now. */\r
+                                       /* For inheritance to have occurred there must have been an\r
+                                       initial timeout, and an adjusted timeout cannot become 0, as\r
+                                       if it were 0 the function would have exited. */\r
+                                       #if( configUSE_MUTEXES == 1 )\r
+                                       {\r
+                                               configASSERT( xInheritanceOccurred == pdFALSE );\r
+                                       }\r
+                                       #endif /* configUSE_MUTEXES */\r
+\r
+                                       /* The semaphore count was 0 and no block time is specified\r
+                                       (or the block time has expired) so exit now. */\r
                                        taskEXIT_CRITICAL();\r
                                        traceQUEUE_RECEIVE_FAILED( pxQueue );\r
                                        return errQUEUE_EMPTY;\r
                                }\r
                                else if( xEntryTimeSet == pdFALSE )\r
                                {\r
-                                       /* The queue was empty and a block time was specified so\r
-                                       configure the timeout structure. */\r
-                                       vTaskSetTimeOutState( &xTimeOut );\r
+                                       /* The semaphore count was 0 and a block time was specified\r
+                                       so configure the timeout structure ready to block. */\r
+                                       vTaskInternalSetTimeOutState( &xTimeOut );\r
                                        xEntryTimeSet = pdTRUE;\r
                                }\r
                                else\r
@@ -1390,7 +1497,7 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                }\r
                taskEXIT_CRITICAL();\r
 \r
-               /* Interrupts and other tasks can send to and receive from the queue\r
+               /* Interrupts and other tasks can give to and take from the semaphore\r
                now the critical section has been exited. */\r
 \r
                vTaskSuspendAll();\r
@@ -1399,6 +1506,10 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                /* Update the timeout state to see if it has expired yet. */\r
                if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
                {\r
+                       /* A block time is specified and not expired.  If the semaphore\r
+                       count is 0 then enter the Blocked state to wait for a semaphore to\r
+                       become available.  As semaphores are implemented with queues the\r
+                       queue being empty is equivalent to the semaphore count being 0. */\r
                        if( prvIsQueueEmpty( pxQueue ) != pdFALSE )\r
                        {\r
                                traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );\r
@@ -1409,7 +1520,7 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                                        {\r
                                                taskENTER_CRITICAL();\r
                                                {\r
-                                                       vTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );\r
+                                                       xInheritanceOccurred = xTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );\r
                                                }\r
                                                taskEXIT_CRITICAL();\r
                                        }\r
@@ -1433,18 +1544,48 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
                        }\r
                        else\r
                        {\r
-                               /* Try again. */\r
+                               /* There was no timeout and the semaphore count was not 0, so\r
+                               attempt to take the semaphore again. */\r
                                prvUnlockQueue( pxQueue );\r
                                ( void ) xTaskResumeAll();\r
                        }\r
                }\r
                else\r
                {\r
+                       /* Timed out. */\r
                        prvUnlockQueue( pxQueue );\r
                        ( void ) xTaskResumeAll();\r
 \r
+                       /* If the semaphore count is 0 exit now as the timeout has\r
+                       expired.  Otherwise return to attempt to take the semaphore that is\r
+                       known to be available.  As semaphores are implemented by queues the\r
+                       queue being empty is equivalent to the semaphore count being 0. */\r
                        if( prvIsQueueEmpty( pxQueue ) != pdFALSE )\r
                        {\r
+                               #if ( configUSE_MUTEXES == 1 )\r
+                               {\r
+                                       /* xInheritanceOccurred could only have be set if\r
+                                       pxQueue->uxQueueType == queueQUEUE_IS_MUTEX so no need to\r
+                                       test the mutex type again to check it is actually a mutex. */\r
+                                       if( xInheritanceOccurred != pdFALSE )\r
+                                       {\r
+                                               taskENTER_CRITICAL();\r
+                                               {\r
+                                                       UBaseType_t uxHighestWaitingPriority;\r
+\r
+                                                       /* This task blocking on the mutex caused another\r
+                                                       task to inherit this task's priority.  Now this task\r
+                                                       has timed out the priority should be disinherited\r
+                                                       again, but only as low as the next highest priority\r
+                                                       task that is waiting for the same mutex. */\r
+                                                       uxHighestWaitingPriority = prvGetDisinheritPriorityAfterTimeout( pxQueue );\r
+                                                       vTaskPriorityDisinheritAfterTimeout( ( void * ) pxQueue->pxMutexHolder, uxHighestWaitingPriority );\r
+                                               }\r
+                                               taskEXIT_CRITICAL();\r
+                                       }\r
+                               }\r
+                               #endif /* configUSE_MUTEXES */\r
+\r
                                traceQUEUE_RECEIVE_FAILED( pxQueue );\r
                                return errQUEUE_EMPTY;\r
                        }\r
@@ -1457,6 +1598,156 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
 }\r
 /*-----------------------------------------------------------*/\r
 \r
+BaseType_t xQueuePeek( QueueHandle_t xQueue, void * const pvBuffer, TickType_t xTicksToWait )\r
+{\r
+BaseType_t xEntryTimeSet = pdFALSE;\r
+TimeOut_t xTimeOut;\r
+int8_t *pcOriginalReadPosition;\r
+Queue_t * const pxQueue = ( Queue_t * ) xQueue;\r
+\r
+       /* Check the pointer is not NULL. */\r
+       configASSERT( ( pxQueue ) );\r
+\r
+       /* The buffer into which data is received can only be NULL if the data size\r
+       is zero (so no data is copied into the buffer. */\r
+       configASSERT( !( ( ( pvBuffer ) == NULL ) && ( ( pxQueue )->uxItemSize != ( UBaseType_t ) 0U ) ) );\r
+\r
+       /* Cannot block if the scheduler is suspended. */\r
+       #if ( ( INCLUDE_xTaskGetSchedulerState == 1 ) || ( configUSE_TIMERS == 1 ) )\r
+       {\r
+               configASSERT( !( ( xTaskGetSchedulerState() == taskSCHEDULER_SUSPENDED ) && ( xTicksToWait != 0 ) ) );\r
+       }\r
+       #endif\r
+\r
+\r
+       /* This function relaxes the coding standard somewhat to allow return\r
+       statements within the function itself.  This is done in the interest\r
+       of execution time efficiency. */\r
+\r
+       for( ;; )\r
+       {\r
+               taskENTER_CRITICAL();\r
+               {\r
+                       const UBaseType_t uxMessagesWaiting = pxQueue->uxMessagesWaiting;\r
+\r
+                       /* Is there data in the queue now?  To be running the calling task\r
+                       must be the highest priority task wanting to access the queue. */\r
+                       if( uxMessagesWaiting > ( UBaseType_t ) 0 )\r
+                       {\r
+                               /* Remember the read position so it can be reset after the data\r
+                               is read from the queue as this function is only peeking the\r
+                               data, not removing it. */\r
+                               pcOriginalReadPosition = pxQueue->u.pcReadFrom;\r
+\r
+                               prvCopyDataFromQueue( pxQueue, pvBuffer );\r
+                               traceQUEUE_PEEK( pxQueue );\r
+\r
+                               /* The data is not being removed, so reset the read pointer. */\r
+                               pxQueue->u.pcReadFrom = pcOriginalReadPosition;\r
+\r
+                               /* The data is being left in the queue, so see if there are\r
+                               any other tasks waiting for the data. */\r
+                               if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) == pdFALSE )\r
+                               {\r
+                                       if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
+                                       {\r
+                                               /* The task waiting has a higher priority than this task. */\r
+                                               queueYIELD_IF_USING_PREEMPTION();\r
+                                       }\r
+                                       else\r
+                                       {\r
+                                               mtCOVERAGE_TEST_MARKER();\r
+                                       }\r
+                               }\r
+                               else\r
+                               {\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
+\r
+                               taskEXIT_CRITICAL();\r
+                               return pdPASS;\r
+                       }\r
+                       else\r
+                       {\r
+                               if( xTicksToWait == ( TickType_t ) 0 )\r
+                               {\r
+                                       /* The queue was empty and no block time is specified (or\r
+                                       the block time has expired) so leave now. */\r
+                                       taskEXIT_CRITICAL();\r
+                                       traceQUEUE_PEEK_FAILED( pxQueue );\r
+                                       return errQUEUE_EMPTY;\r
+                               }\r
+                               else if( xEntryTimeSet == pdFALSE )\r
+                               {\r
+                                       /* The queue was empty and a block time was specified so\r
+                                       configure the timeout structure ready to enter the blocked\r
+                                       state. */\r
+                                       vTaskInternalSetTimeOutState( &xTimeOut );\r
+                                       xEntryTimeSet = pdTRUE;\r
+                               }\r
+                               else\r
+                               {\r
+                                       /* Entry time was already set. */\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
+                       }\r
+               }\r
+               taskEXIT_CRITICAL();\r
+\r
+               /* Interrupts and other tasks can send to and receive from the queue\r
+               now the critical section has been exited. */\r
+\r
+               vTaskSuspendAll();\r
+               prvLockQueue( pxQueue );\r
+\r
+               /* Update the timeout state to see if it has expired yet. */\r
+               if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
+               {\r
+                       /* Timeout has not expired yet, check to see if there is data in the\r
+                       queue now, and if not enter the Blocked state to wait for data. */\r
+                       if( prvIsQueueEmpty( pxQueue ) != pdFALSE )\r
+                       {\r
+                               traceBLOCKING_ON_QUEUE_PEEK( pxQueue );\r
+                               vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );\r
+                               prvUnlockQueue( pxQueue );\r
+                               if( xTaskResumeAll() == pdFALSE )\r
+                               {\r
+                                       portYIELD_WITHIN_API();\r
+                               }\r
+                               else\r
+                               {\r
+                                       mtCOVERAGE_TEST_MARKER();\r
+                               }\r
+                       }\r
+                       else\r
+                       {\r
+                               /* There is data in the queue now, so don't enter the blocked\r
+                               state, instead return to try and obtain the data. */\r
+                               prvUnlockQueue( pxQueue );\r
+                               ( void ) xTaskResumeAll();\r
+                       }\r
+               }\r
+               else\r
+               {\r
+                       /* The timeout has expired.  If there is still no data in the queue\r
+                       exit, otherwise go back and try to read the data again. */\r
+                       prvUnlockQueue( pxQueue );\r
+                       ( void ) xTaskResumeAll();\r
+\r
+                       if( prvIsQueueEmpty( pxQueue ) != pdFALSE )\r
+                       {\r
+                               traceQUEUE_PEEK_FAILED( pxQueue );\r
+                               return errQUEUE_EMPTY;\r
+                       }\r
+                       else\r
+                       {\r
+                               mtCOVERAGE_TEST_MARKER();\r
+                       }\r
+               }\r
+       }\r
+}\r
+/*-----------------------------------------------------------*/\r
+\r
 BaseType_t xQueueReceiveFromISR( QueueHandle_t xQueue, void * const pvBuffer, BaseType_t * const pxHigherPriorityTaskWoken )\r
 {\r
 BaseType_t xReturn;\r
@@ -1720,6 +2011,33 @@ Queue_t * const pxQueue = ( Queue_t * ) xQueue;
 #endif /* configUSE_TRACE_FACILITY */\r
 /*-----------------------------------------------------------*/\r
 \r
+#if( configUSE_MUTEXES == 1 )\r
+\r
+       static UBaseType_t prvGetDisinheritPriorityAfterTimeout( const Queue_t * const pxQueue )\r
+       {\r
+       UBaseType_t uxHighestPriorityOfWaitingTasks;\r
+\r
+               /* If a task waiting for a mutex causes the mutex holder to inherit a\r
+               priority, but the waiting task times out, then the holder should\r
+               disinherit the priority - but only down to the highest priority of any\r
+               other tasks that are waiting for the same mutex.  For this purpose,\r
+               return the priority of the highest priority task that is waiting for the\r
+               mutex. */\r
+               if( listCURRENT_LIST_LENGTH( &( pxQueue->xTasksWaitingToReceive ) ) > 0 )\r
+               {\r
+                       uxHighestPriorityOfWaitingTasks = configMAX_PRIORITIES - listGET_ITEM_VALUE_OF_HEAD_ENTRY( &( pxQueue->xTasksWaitingToReceive ) );\r
+               }\r
+               else\r
+               {\r
+                       uxHighestPriorityOfWaitingTasks = tskIDLE_PRIORITY;\r
+               }\r
+\r
+               return uxHighestPriorityOfWaitingTasks;\r
+       }\r
+\r
+#endif /* configUSE_MUTEXES */\r
+/*-----------------------------------------------------------*/\r
+\r
 static BaseType_t prvCopyDataToQueue( Queue_t * const pxQueue, const void *pvItemToQueue, const BaseType_t xPosition )\r
 {\r
 BaseType_t xReturn = pdFALSE;\r
@@ -2504,7 +2822,7 @@ BaseType_t xReturn;
        {\r
        QueueSetMemberHandle_t xReturn = NULL;\r
 \r
-               ( void ) xQueueGenericReceive( ( QueueHandle_t ) xQueueSet, &xReturn, xTicksToWait, pdFALSE ); /*lint !e961 Casting from one typedef to another is not redundant. */\r
+               ( void ) xQueueReceive( ( QueueHandle_t ) xQueueSet, &xReturn, xTicksToWait ); /*lint !e961 Casting from one typedef to another is not redundant. */\r
                return xReturn;\r
        }\r
 \r