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

   1 /*\r
   2         FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry.\r
   3 \r
   4         This file is part of the FreeRTOS.org distribution.\r
   5 \r
   6         FreeRTOS.org is free software; you can redistribute it and/or modify\r
   7         it under the terms of the GNU General Public License as published by\r
   8         the Free Software Foundation; either version 2 of the License, or\r
   9         (at your option) any later version.\r
  10 \r
  11         FreeRTOS.org is distributed in the hope that it will be useful,\r
  12         but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14         GNU General Public License for more details.\r
  15 \r
  16         You should have received a copy of the GNU General Public License\r
  17         along with FreeRTOS.org; if not, write to the Free Software\r
  18         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\r
  19 \r
  20         A special exception to the GPL can be applied should you wish to distribute\r
  21         a combined work that includes FreeRTOS.org, without being obliged to provide\r
  22         the source code for any proprietary components.  See the licensing section\r
  23         of http://www.FreeRTOS.org for full details of how and when the exception\r
  24         can be applied.\r
  25 \r
  26     ***************************************************************************\r
  27     ***************************************************************************\r
  28     *                                                                         *\r
  29     * Get the FreeRTOS eBook!  See http://www.FreeRTOS.org/Documentation      *\r
  30         *                                                                         *\r
  31         * This is a concise, step by step, 'hands on' guide that describes both   *\r
  32         * general multitasking concepts and FreeRTOS specifics. It presents and   *\r
  33         * explains numerous examples that are written using the FreeRTOS API.     *\r
  34         * Full source code for all the examples is provided in an accompanying    *\r
  35         * .zip file.                                                              *\r
  36     *                                                                         *\r
  37     ***************************************************************************\r
  38     ***************************************************************************\r
  39 \r
  40         Please ensure to read the configuration and relevant port sections of the\r
  41         online documentation.\r
  42 \r
  43         http://www.FreeRTOS.org - Documentation, latest information, license and\r
  44         contact details.\r
  45 \r
  46         http://www.SafeRTOS.com - A version that is certified for use in safety\r
  47         critical systems.\r
  48 \r
  49         http://www.OpenRTOS.com - Commercial support, development, porting,\r
  50         licensing and training services.\r
  51 */\r
  52 \r
  53 #include <stdlib.h>\r
  54 #include <string.h>\r
  55 #include "FreeRTOS.h"\r
  56 #include "task.h"\r
  57 #include "croutine.h"\r
  58 \r
  59 /*-----------------------------------------------------------\r
  60  * PUBLIC LIST API documented in list.h\r
  61  *----------------------------------------------------------*/\r
  62 \r
  63 /* Constants used with the cRxLock and cTxLock structure members. */\r
  64 #define queueUNLOCKED                                                   ( ( signed portBASE_TYPE ) -1 )\r
  65 #define queueLOCKED_UNMODIFIED                                  ( ( signed portBASE_TYPE ) 0 )\r
  66 \r
  67 #define queueERRONEOUS_UNBLOCK                                  ( -1 )\r
  68 \r
  69 /* For internal use only. */\r
  70 #define queueSEND_TO_BACK       ( 0 )\r
  71 #define queueSEND_TO_FRONT      ( 1 )\r
  72 \r
  73 /* Effectively make a union out of the xQUEUE structure. */\r
  74 #define pxMutexHolder                           pcTail\r
  75 #define uxQueueType                                     pcHead\r
  76 #define uxRecursiveCallCount            pcReadFrom\r
  77 #define queueQUEUE_IS_MUTEX                     NULL\r
  78 \r
  79 /* Semaphores do not actually store or copy data, so have an items size of\r
  80 zero. */\r
  81 #define queueSEMAPHORE_QUEUE_ITEM_LENGTH ( 0 )\r
  82 #define queueDONT_BLOCK                                  ( ( portTickType ) 0 )\r
  83 #define queueMUTEX_GIVE_BLOCK_TIME               ( ( portTickType ) 0 )\r
  84 \r
  85 /*\r
  86  * Definition of the queue used by the scheduler.\r
  87  * Items are queued by copy, not reference.\r
  88  */\r
  89 typedef struct QueueDefinition\r
  90 {\r
  91         signed portCHAR *pcHead;                                /*< Points to the beginning of the queue storage area. */\r
  92         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. */\r
  93 \r
  94         signed portCHAR *pcWriteTo;                             /*< Points to the free next place in the storage area. */\r
  95         signed portCHAR *pcReadFrom;                    /*< Points to the last place that a queued item was read from. */\r
  96 \r
  97         xList xTasksWaitingToSend;                              /*< List of tasks that are blocked waiting to post onto this queue.  Stored in priority order. */\r
  98         xList xTasksWaitingToReceive;                   /*< List of tasks that are blocked waiting to read from this queue.  Stored in priority order. */\r
  99 \r
 100         volatile unsigned portBASE_TYPE uxMessagesWaiting;/*< The number of items currently in the queue. */\r
 101         unsigned portBASE_TYPE uxLength;                /*< The length of the queue defined as the number of items it will hold, not the number of bytes. */\r
 102         unsigned portBASE_TYPE uxItemSize;              /*< The size of each items that the queue will hold. */\r
 103 \r
 104         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. */\r
 105         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. */\r
 106 \r
 107 } xQUEUE;\r
 108 /*-----------------------------------------------------------*/\r
 109 \r
 110 /*\r
 111  * Inside this file xQueueHandle is a pointer to a xQUEUE structure.\r
 112  * To keep the definition private the API header file defines it as a\r
 113  * pointer to void.\r
 114  */\r
 115 typedef xQUEUE * xQueueHandle;\r
 116 \r
 117 /*\r
 118  * Prototypes for public functions are included here so we don't have to\r
 119  * include the API header file (as it defines xQueueHandle differently).  These\r
 120  * functions are documented in the API header file.\r
 121  */\r
 122 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize );\r
 123 signed portBASE_TYPE xQueueGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );\r
 124 unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle pxQueue );\r
 125 void vQueueDelete( xQueueHandle xQueue );\r
 126 signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle pxQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition );\r
 127 signed portBASE_TYPE xQueueGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking );\r
 128 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void * const pvBuffer, signed portBASE_TYPE *pxTaskWoken );\r
 129 xQueueHandle xQueueCreateMutex( void );\r
 130 xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxCountValue, unsigned portBASE_TYPE uxInitialCount );\r
 131 portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle xMutex, portTickType xBlockTime );\r
 132 portBASE_TYPE xQueueGiveMutexRecursive( xQueueHandle xMutex );\r
 133 signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );\r
 134 signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking );\r
 135 signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle pxQueue );\r
 136 signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle pxQueue );\r
 137 unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle pxQueue );\r
 138 \r
 139 /*\r
 140  * Co-routine queue functions differ from task queue functions.  Co-routines are\r
 141  * an optional component.\r
 142  */\r
 143 #if configUSE_CO_ROUTINES == 1\r
 144         signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken );\r
 145         signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );\r
 146         signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait );\r
 147         signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );\r
 148 #endif\r
 149 \r
 150 /*\r
 151  * The queue registry is just a means for kernel aware debuggers to locate\r
 152  * queue structures.  It has no other purpose so is an optional component.\r
 153  */\r
 154 #if configQUEUE_REGISTRY_SIZE > 0\r
 155 \r
 156         /* The type stored within the queue registry array.  This allows a name\r
 157         to be assigned to each queue making kernel aware debugging a little\r
 158         more user friendly. */\r
 159         typedef struct QUEUE_REGISTRY_ITEM\r
 160         {\r
 161                 signed portCHAR *pcQueueName;\r
 162                 xQueueHandle xHandle;\r
 163         } xQueueRegistryItem;\r
 164 \r
 165         /* The queue registry is simply an array of xQueueRegistryItem structures.\r
 166         The pcQueueName member of a structure being NULL is indicative of the\r
 167         array position being vacant. */\r
 168         xQueueRegistryItem xQueueRegistry[ configQUEUE_REGISTRY_SIZE ];\r
 169 \r
 170         /* Removes a queue from the registry by simply setting the pcQueueName\r
 171         member to NULL. */\r
 172         static void vQueueUnregisterQueue( xQueueHandle xQueue );\r
 173         void vQueueAddToRegistry( xQueueHandle xQueue, signed portCHAR *pcQueueName );\r
 174 #endif\r
 175 \r
 176 /*\r
 177  * Unlocks a queue locked by a call to prvLockQueue.  Locking a queue does not\r
 178  * prevent an ISR from adding or removing items to the queue, but does prevent\r
 179  * an ISR from removing tasks from the queue event lists.  If an ISR finds a\r
 180  * queue is locked it will instead increment the appropriate queue lock count\r
 181  * to indicate that a task may require unblocking.  When the queue in unlocked\r
 182  * these lock counts are inspected, and the appropriate action taken.\r
 183  */\r
 184 static void prvUnlockQueue( xQueueHandle pxQueue );\r
 185 \r
 186 /*\r
 187  * Uses a critical section to determine if there is any data in a queue.\r
 188  *\r
 189  * @return pdTRUE if the queue contains no items, otherwise pdFALSE.\r
 190  */\r
 191 static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue );\r
 192 \r
 193 /*\r
 194  * Uses a critical section to determine if there is any space in a queue.\r
 195  *\r
 196  * @return pdTRUE if there is no space, otherwise pdFALSE;\r
 197  */\r
 198 static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue );\r
 199 \r
 200 /*\r
 201  * Copies an item into the queue, either at the front of the queue or the\r
 202  * back of the queue.\r
 203  */\r
 204 static void prvCopyDataToQueue( xQUEUE *pxQueue, const void *pvItemToQueue, portBASE_TYPE xPosition );\r
 205 \r
 206 /*\r
 207  * Copies an item out of a queue.\r
 208  */\r
 209 static void prvCopyDataFromQueue( xQUEUE * const pxQueue, const void *pvBuffer );\r
 210 /*-----------------------------------------------------------*/\r
 211 \r
 212 /*\r
 213  * Macro to mark a queue as locked.  Locking a queue prevents an ISR from\r
 214  * accessing the queue event lists.\r
 215  */\r
 216 #define prvLockQueue( pxQueue )                                                 \\r
 217 {                                                                                                               \\r
 218         taskENTER_CRITICAL();                                                           \\r
 219         {                                                                                                       \\r
 220                 if( pxQueue->xRxLock == queueUNLOCKED )                 \\r
 221                 {                                                                                               \\r
 222                         pxQueue->xRxLock = queueLOCKED_UNMODIFIED;      \\r
 223                 }                                                                                               \\r
 224                 if( pxQueue->xTxLock == queueUNLOCKED )                 \\r
 225                 {                                                                                               \\r
 226                         pxQueue->xTxLock = queueLOCKED_UNMODIFIED;      \\r
 227                 }                                                                                               \\r
 228         }                                                                                                       \\r
 229         taskEXIT_CRITICAL();                                                            \\r
 230 }\r
 231 /*-----------------------------------------------------------*/\r
 232 \r
 233 \r
 234 /*-----------------------------------------------------------\r
 235  * PUBLIC QUEUE MANAGEMENT API documented in queue.h\r
 236  *----------------------------------------------------------*/\r
 237 \r
 238 xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize )\r
 239 {\r
 240 xQUEUE *pxNewQueue;\r
 241 size_t xQueueSizeInBytes;\r
 242 \r
 243         /* Allocate the new queue structure. */\r
 244         if( uxQueueLength > ( unsigned portBASE_TYPE ) 0 )\r
 245         {\r
 246                 pxNewQueue = ( xQUEUE * ) pvPortMalloc( sizeof( xQUEUE ) );\r
 247                 if( pxNewQueue != NULL )\r
 248                 {\r
 249                         /* Create the list of pointers to queue items.  The queue is one byte\r
 250                         longer than asked for to make wrap checking easier/faster. */\r
 251                         xQueueSizeInBytes = ( size_t ) ( uxQueueLength * uxItemSize ) + ( size_t ) 1;\r
 252 \r
 253                         pxNewQueue->pcHead = ( signed portCHAR * ) pvPortMalloc( xQueueSizeInBytes );\r
 254                         if( pxNewQueue->pcHead != NULL )\r
 255                         {\r
 256                                 /* Initialise the queue members as described above where the\r
 257                                 queue type is defined. */\r
 258                                 pxNewQueue->pcTail = pxNewQueue->pcHead + ( uxQueueLength * uxItemSize );\r
 259                                 pxNewQueue->uxMessagesWaiting = 0;\r
 260                                 pxNewQueue->pcWriteTo = pxNewQueue->pcHead;\r
 261                                 pxNewQueue->pcReadFrom = pxNewQueue->pcHead + ( ( uxQueueLength - 1 ) * uxItemSize );\r
 262                                 pxNewQueue->uxLength = uxQueueLength;\r
 263                                 pxNewQueue->uxItemSize = uxItemSize;\r
 264                                 pxNewQueue->xRxLock = queueUNLOCKED;\r
 265                                 pxNewQueue->xTxLock = queueUNLOCKED;\r
 266 \r
 267                                 /* Likewise ensure the event queues start with the correct state. */\r
 268                                 vListInitialise( &( pxNewQueue->xTasksWaitingToSend ) );\r
 269                                 vListInitialise( &( pxNewQueue->xTasksWaitingToReceive ) );\r
 270 \r
 271                                 traceQUEUE_CREATE( pxNewQueue );\r
 272 \r
 273                                 return  pxNewQueue;\r
 274                         }\r
 275                         else\r
 276                         {\r
 277                                 traceQUEUE_CREATE_FAILED();\r
 278                                 vPortFree( pxNewQueue );\r
 279                         }\r
 280                 }\r
 281         }\r
 282 \r
 283         /* Will only reach here if we could not allocate enough memory or no memory\r
 284         was required. */\r
 285         return NULL;\r
 286 }\r
 287 /*-----------------------------------------------------------*/\r
 288 \r
 289 #if ( configUSE_MUTEXES == 1 )\r
 290 \r
 291         xQueueHandle xQueueCreateMutex( void )\r
 292         {\r
 293         xQUEUE *pxNewQueue;\r
 294 \r
 295                 /* Allocate the new queue structure. */\r
 296                 pxNewQueue = ( xQUEUE * ) pvPortMalloc( sizeof( xQUEUE ) );\r
 297                 if( pxNewQueue != NULL )\r
 298                 {\r
 299                         /* Information required for priority inheritance. */\r
 300                         pxNewQueue->pxMutexHolder = NULL;\r
 301                         pxNewQueue->uxQueueType = queueQUEUE_IS_MUTEX;\r
 302 \r
 303                         /* Queues used as a mutex no data is actually copied into or out\r
 304                         of the queue. */\r
 305                         pxNewQueue->pcWriteTo = NULL;\r
 306                         pxNewQueue->pcReadFrom = NULL;\r
 307 \r
 308                         /* Each mutex has a length of 1 (like a binary semaphore) and\r
 309                         an item size of 0 as nothing is actually copied into or out\r
 310                         of the mutex. */\r
 311                         pxNewQueue->uxMessagesWaiting = 0;\r
 312                         pxNewQueue->uxLength = 1;\r
 313                         pxNewQueue->uxItemSize = 0;\r
 314                         pxNewQueue->xRxLock = queueUNLOCKED;\r
 315                         pxNewQueue->xTxLock = queueUNLOCKED;\r
 316 \r
 317                         /* Ensure the event queues start with the correct state. */\r
 318                         vListInitialise( &( pxNewQueue->xTasksWaitingToSend ) );\r
 319                         vListInitialise( &( pxNewQueue->xTasksWaitingToReceive ) );\r
 320 \r
 321                         /* Start with the semaphore in the expected state. */\r
 322                         xQueueGenericSend( pxNewQueue, NULL, 0, queueSEND_TO_BACK );\r
 323 \r
 324                         traceCREATE_MUTEX( pxNewQueue );\r
 325                 }\r
 326                 else\r
 327                 {\r
 328                         traceCREATE_MUTEX_FAILED();\r
 329                 }\r
 330 \r
 331                 return pxNewQueue;\r
 332         }\r
 333 \r
 334 #endif /* configUSE_MUTEXES */\r
 335 /*-----------------------------------------------------------*/\r
 336 \r
 337 #if configUSE_RECURSIVE_MUTEXES == 1\r
 338 \r
 339         portBASE_TYPE xQueueGiveMutexRecursive( xQueueHandle pxMutex )\r
 340         {\r
 341         portBASE_TYPE xReturn;\r
 342 \r
 343                 /* If this is the task that holds the mutex then pxMutexHolder will not\r
 344                 change outside of this task.  If this task does not hold the mutex then\r
 345                 pxMutexHolder can never coincidentally equal the tasks handle, and as\r
 346                 this is the only condition we are interested in it does not matter if\r
 347                 pxMutexHolder is accessed simultaneously by another task.  Therefore no\r
 348                 mutual exclusion is required to test the pxMutexHolder variable. */\r
 349                 if( pxMutex->pxMutexHolder == xTaskGetCurrentTaskHandle() )\r
 350                 {\r
 351                         traceGIVE_MUTEX_RECURSIVE( pxMutex );\r
 352 \r
 353                         /* uxRecursiveCallCount cannot be zero if pxMutexHolder is equal to\r
 354                         the task handle, therefore no underflow check is required.  Also,\r
 355                         uxRecursiveCallCount is only modified by the mutex holder, and as\r
 356                         there can only be one, no mutual exclusion is required to modify the\r
 357                         uxRecursiveCallCount member. */\r
 358                         ( pxMutex->uxRecursiveCallCount )--;\r
 359 \r
 360                         /* Have we unwound the call count? */\r
 361                         if( pxMutex->uxRecursiveCallCount == 0 )\r
 362                         {\r
 363                                 /* Return the mutex.  This will automatically unblock any other\r
 364                                 task that might be waiting to access the mutex. */\r
 365                 xQueueGenericSend( pxMutex, NULL, queueMUTEX_GIVE_BLOCK_TIME, queueSEND_TO_BACK );\r
 366                         }\r
 367 \r
 368                         xReturn = pdPASS;\r
 369                 }\r
 370                 else\r
 371                 {\r
 372                         /* We cannot give the mutex because we are not the holder. */\r
 373                         xReturn = pdFAIL;\r
 374 \r
 375                         traceGIVE_MUTEX_RECURSIVE_FAILED( pxMutex );\r
 376                 }\r
 377 \r
 378                 return xReturn;\r
 379         }\r
 380 \r
 381 #endif /* configUSE_RECURSIVE_MUTEXES */\r
 382 /*-----------------------------------------------------------*/\r
 383 \r
 384 #if configUSE_RECURSIVE_MUTEXES == 1\r
 385 \r
 386         portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle pxMutex, portTickType xBlockTime )\r
 387         {\r
 388         portBASE_TYPE xReturn;\r
 389 \r
 390                 /* Comments regarding mutual exclusion as per those within\r
 391                 xQueueGiveMutexRecursive(). */\r
 392 \r
 393                 traceTAKE_MUTEX_RECURSIVE( pxMutex );\r
 394 \r
 395                 if( pxMutex->pxMutexHolder == xTaskGetCurrentTaskHandle() )\r
 396                 {\r
 397                         ( pxMutex->uxRecursiveCallCount )++;\r
 398                         xReturn = pdPASS;\r
 399                 }\r
 400                 else\r
 401                 {\r
 402             xReturn = xQueueGenericReceive( pxMutex, NULL, xBlockTime, pdFALSE );\r
 403 \r
 404                         /* pdPASS will only be returned if we successfully obtained the mutex,\r
 405                         we may have blocked to reach here. */\r
 406                         if( xReturn == pdPASS )\r
 407                         {\r
 408                                 ( pxMutex->uxRecursiveCallCount )++;\r
 409                         }\r
 410                 }\r
 411 \r
 412                 return xReturn;\r
 413         }\r
 414 \r
 415 #endif /* configUSE_RECURSIVE_MUTEXES */\r
 416 /*-----------------------------------------------------------*/\r
 417 \r
 418 #if configUSE_COUNTING_SEMAPHORES == 1\r
 419 \r
 420         xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxCountValue, unsigned portBASE_TYPE uxInitialCount )\r
 421         {\r
 422         xQueueHandle pxHandle;\r
 423 \r
 424                 pxHandle = xQueueCreate( ( unsigned portBASE_TYPE ) uxCountValue, queueSEMAPHORE_QUEUE_ITEM_LENGTH );\r
 425 \r
 426                 if( pxHandle != NULL )\r
 427                 {\r
 428                         pxHandle->uxMessagesWaiting = uxInitialCount;\r
 429 \r
 430                         traceCREATE_COUNTING_SEMAPHORE();\r
 431                 }\r
 432                 else\r
 433                 {\r
 434                         traceCREATE_COUNTING_SEMAPHORE_FAILED();\r
 435                 }\r
 436 \r
 437                 return pxHandle;\r
 438         }\r
 439 \r
 440 #endif /* configUSE_COUNTING_SEMAPHORES */\r
 441 /*-----------------------------------------------------------*/\r
 442 \r
 443 signed portBASE_TYPE xQueueGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition )\r
 444 {\r
 445 signed portBASE_TYPE xEntryTimeSet = pdFALSE;\r
 446 xTimeOutType xTimeOut;\r
 447 \r
 448         for( ;; )\r
 449         {\r
 450                 taskENTER_CRITICAL();\r
 451                 {\r
 452                         /* Is there room on the queue now?  To be running we must be\r
 453                         the highest priority task wanting to access the queue. */\r
 454                         if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )\r
 455                         {\r
 456                                 traceQUEUE_SEND( pxQueue );\r
 457                                 prvCopyDataToQueue( pxQueue, pvItemToQueue, xCopyPosition );\r
 458 \r
 459                                 /* If there was a task waiting for data to arrive on the\r
 460                                 queue then unblock it now. */\r
 461                                 if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) == pdFALSE )\r
 462                                 {\r
 463                                         if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) == pdTRUE )\r
 464                                         {\r
 465                                                 /* The unblocked task has a priority higher than\r
 466                                                 our own so yield immediately. */\r
 467                                                 taskYIELD();\r
 468                                         }\r
 469                                 }\r
 470 \r
 471                                 taskEXIT_CRITICAL();\r
 472                                 return pdPASS;\r
 473                         }\r
 474                         else\r
 475                         {\r
 476                                 if( xTicksToWait == ( portTickType ) 0 )\r
 477                                 {\r
 478                                         taskEXIT_CRITICAL();\r
 479                                         return errQUEUE_FULL;\r
 480                                 }\r
 481                                 else if( xEntryTimeSet == pdFALSE )\r
 482                                 {\r
 483                                         vTaskSetTimeOutState( &xTimeOut );\r
 484                                         xEntryTimeSet = pdTRUE;\r
 485                                 }\r
 486                         }\r
 487                 }\r
 488                 taskEXIT_CRITICAL();    \r
 489 \r
 490                 vTaskSuspendAll();\r
 491                 prvLockQueue( pxQueue );\r
 492 \r
 493                 if( prvIsQueueFull( pxQueue ) )\r
 494                 {\r
 495                 /* Need to call xTaskCheckForTimeout again as time could\r
 496                 have passed since it was last called if this is not the\r
 497                 first time around this loop.  */\r
 498                         if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
 499                         {\r
 500                                 traceBLOCKING_ON_QUEUE_SEND( pxQueue );\r
 501                                 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );\r
 502 \r
 503                                 /* Unlocking the queue means queue events can effect the\r
 504                                 event list.  It is possible     that interrupts occurring now\r
 505                                 remove this task from the event list again - but as the\r
 506                                 scheduler is suspended the task will go onto the pending\r
 507                                 ready last instead of the actual ready list. */\r
 508                                 prvUnlockQueue( pxQueue );\r
 509 \r
 510                                 /* Resuming the scheduler will move tasks from the pending\r
 511                                 ready list into the ready list - so it is feasible that this\r
 512                                 task is already in a ready list before it yields - in which\r
 513                                 case the yield will not cause a context switch unless there\r
 514                                 is also a higher priority task in the pending ready list. */\r
 515                                 if( !xTaskResumeAll() )\r
 516                                 {\r
 517                                         taskYIELD();\r
 518                                 }\r
 519                         }\r
 520                         else\r
 521                         {\r
 522                                 prvUnlockQueue( pxQueue );\r
 523                                 ( void ) xTaskResumeAll();\r
 524                                 return errQUEUE_FULL;\r
 525                         }\r
 526                 }\r
 527                 else\r
 528                 {\r
 529                         prvUnlockQueue( pxQueue );\r
 530                         ( void ) xTaskResumeAll();\r
 531                 }\r
 532         }\r
 533 }\r
 534 /*-----------------------------------------------------------*/\r
 535 \r
 536 #if configUSE_ALTERNATIVE_API == 1\r
 537 \r
 538         signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition )\r
 539         {\r
 540         signed portBASE_TYPE xEntryTimeSet = pdFALSE;\r
 541         xTimeOutType xTimeOut;\r
 542 \r
 543                 for( ;; )\r
 544                 {\r
 545                         taskENTER_CRITICAL();\r
 546                         {\r
 547                                 /* Is there room on the queue now?  To be running we must be\r
 548                                 the highest priority task wanting to access the queue. */\r
 549                                 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )\r
 550                                 {\r
 551                                         traceQUEUE_SEND( pxQueue );\r
 552                                         prvCopyDataToQueue( pxQueue, pvItemToQueue, xCopyPosition );\r
 553 \r
 554                                         /* If there was a task waiting for data to arrive on the\r
 555                                         queue then unblock it now. */\r
 556                                         if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) == pdFALSE )\r
 557                                         {\r
 558                                                 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) == pdTRUE )\r
 559                                                 {\r
 560                                                         /* The unblocked task has a priority higher than\r
 561                                                         our own so yield immediately. */\r
 562                                                         taskYIELD();\r
 563                                                 }\r
 564                                         }\r
 565 \r
 566                                         taskEXIT_CRITICAL();\r
 567                                         return pdPASS;\r
 568                                 }\r
 569                                 else\r
 570                                 {\r
 571                                         if( xTicksToWait == ( portTickType ) 0 )\r
 572                                         {\r
 573                                                 taskEXIT_CRITICAL();\r
 574                                                 return errQUEUE_FULL;\r
 575                                         }\r
 576                                         else if( xEntryTimeSet == pdFALSE )\r
 577                                         {\r
 578                                                 vTaskSetTimeOutState( &xTimeOut );\r
 579                                                 xEntryTimeSet = pdTRUE;\r
 580                                         }\r
 581                                 }\r
 582                         }\r
 583                         taskEXIT_CRITICAL();    \r
 584 \r
 585                         taskENTER_CRITICAL();\r
 586                         {\r
 587                                 if( prvIsQueueFull( pxQueue ) )\r
 588                                 {\r
 589                                 /* Need to call xTaskCheckForTimeout again as time could\r
 590                                 have passed since it was last called if this is not the\r
 591                                 first time around this loop.  */\r
 592                                         if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
 593                                         {\r
 594                                                 traceBLOCKING_ON_QUEUE_SEND( pxQueue );\r
 595                                                 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );\r
 596                                                 taskYIELD();\r
 597                                         }\r
 598                                         else\r
 599                                         {\r
 600                                                 taskEXIT_CRITICAL();\r
 601                                                 return errQUEUE_FULL;\r
 602                                         }\r
 603                                 }\r
 604                         }\r
 605                         taskEXIT_CRITICAL();\r
 606                 }\r
 607         }\r
 608 \r
 609 #endif /* configUSE_ALTERNATIVE_API */\r
 610 /*-----------------------------------------------------------*/\r
 611 \r
 612 #if configUSE_ALTERNATIVE_API == 1\r
 613 \r
 614         signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking )\r
 615         {\r
 616         signed portBASE_TYPE xEntryTimeSet = pdFALSE;\r
 617         xTimeOutType xTimeOut;\r
 618         signed portCHAR *pcOriginalReadPosition;\r
 619 \r
 620                 for( ;; )\r
 621                 {\r
 622                         taskENTER_CRITICAL();\r
 623                         {\r
 624                                 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )\r
 625                                 {\r
 626                                         /* Remember our read position in case we are just peeking. */\r
 627                                         pcOriginalReadPosition = pxQueue->pcReadFrom;\r
 628 \r
 629                                         prvCopyDataFromQueue( pxQueue, pvBuffer );\r
 630 \r
 631                                         if( xJustPeeking == pdFALSE )\r
 632                                         {\r
 633                                                 traceQUEUE_RECEIVE( pxQueue );\r
 634 \r
 635                                                 /* We are actually removing data. */\r
 636                                                 --( pxQueue->uxMessagesWaiting );\r
 637 \r
 638                                                 #if ( configUSE_MUTEXES == 1 )\r
 639                                                 {\r
 640                                                         if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
 641                                                         {\r
 642                                                                 /* Record the information required to implement\r
 643                                                                 priority inheritance should it become necessary. */\r
 644                                                                 pxQueue->pxMutexHolder = xTaskGetCurrentTaskHandle();\r
 645                                                         }\r
 646                                                 }\r
 647                                                 #endif\r
 648 \r
 649                                                 if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) == pdFALSE )\r
 650                                                 {\r
 651                                                         if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) == pdTRUE )\r
 652                                                         {\r
 653                                                                 taskYIELD();\r
 654                                                         }\r
 655                                                 }\r
 656                                         }\r
 657                                         else\r
 658                                         {\r
 659                                                 traceQUEUE_PEEK( pxQueue );\r
 660 \r
 661                                                 /* We are not removing the data, so reset our read\r
 662                                                 pointer. */\r
 663                                                 pxQueue->pcReadFrom = pcOriginalReadPosition;\r
 664 \r
 665                                                 /* The data is being left in the queue, so see if there are\r
 666                                                 any other tasks waiting for the data. */\r
 667                                                 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )\r
 668                                                 {\r
 669                                                         /* Tasks that are removed from the event list will get added to\r
 670                                                         the pending ready list as the scheduler is still suspended. */\r
 671                                                         if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
 672                                                         {\r
 673                                                                 /* The task waiting has a higher priority than this task. */\r
 674                                                                 taskYIELD();\r
 675                                                         }\r
 676                                                 }\r
 677 \r
 678                                         }\r
 679 \r
 680                                         taskEXIT_CRITICAL();\r
 681                                         return pdPASS;\r
 682                                 }\r
 683                                 else\r
 684                                 {\r
 685                                         if( xTicksToWait == ( portTickType ) 0 )\r
 686                                         {\r
 687                                                 taskEXIT_CRITICAL();\r
 688                                                 return errQUEUE_EMPTY;\r
 689                                         }\r
 690                                         else if( xEntryTimeSet == pdFALSE )\r
 691                                         {\r
 692                                                 vTaskSetTimeOutState( &xTimeOut );\r
 693                                                 xEntryTimeSet = pdTRUE;\r
 694                                         }\r
 695                                 }\r
 696                         }\r
 697                         taskEXIT_CRITICAL();\r
 698 \r
 699                         taskENTER_CRITICAL();\r
 700                         {\r
 701                                 if( prvIsQueueEmpty( pxQueue ) )\r
 702                                 {\r
 703                                 /* Need to call xTaskCheckForTimeout again as time could\r
 704                                 have passed since it was last called if this is not the\r
 705                                 first time around this loop. */\r
 706                                         if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
 707                                         {\r
 708                                                 traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );\r
 709 \r
 710                                                 #if ( configUSE_MUTEXES == 1 )\r
 711                                                 {\r
 712                                                         if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
 713                                                         {\r
 714                                                                 portENTER_CRITICAL();\r
 715                                                                         vTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );\r
 716                                                                 portEXIT_CRITICAL();\r
 717                                                         }\r
 718                                                 }\r
 719                                                 #endif\r
 720 \r
 721                                                 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );\r
 722                                                 taskYIELD();\r
 723                                         }\r
 724                                         else\r
 725                                         {\r
 726                                                 taskEXIT_CRITICAL();\r
 727                                                 return errQUEUE_EMPTY;\r
 728                                         }\r
 729                                 }\r
 730                         }\r
 731                         taskEXIT_CRITICAL();\r
 732                 }\r
 733         }\r
 734 \r
 735 \r
 736 #endif /* configUSE_ALTERNATIVE_API */\r
 737 /*-----------------------------------------------------------*/\r
 738 \r
 739 signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle pxQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition )\r
 740 {\r
 741 signed portBASE_TYPE xReturn;\r
 742 unsigned portBASE_TYPE uxSavedInterruptStatus;\r
 743 \r
 744         /* Similar to xQueueGenericSend, except we don't block if there is no room\r
 745         in the queue.  Also we don't directly wake a task that was blocked on a\r
 746         queue read, instead we return a flag to say whether a context switch is\r
 747         required or not (i.e. has a task with a higher priority than us been woken\r
 748         by this post). */\r
 749         uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();\r
 750         {\r
 751                 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )\r
 752                 {\r
 753                         traceQUEUE_SEND_FROM_ISR( pxQueue );\r
 754 \r
 755                         prvCopyDataToQueue( pxQueue, pvItemToQueue, xCopyPosition );\r
 756 \r
 757                         /* If the queue is locked we do not alter the event list.  This will\r
 758                         be done when the queue is unlocked later. */\r
 759                         if( pxQueue->xTxLock == queueUNLOCKED )\r
 760                         {\r
 761                                 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )\r
 762                                 {\r
 763                                         if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
 764                                         {\r
 765                                                 /* The task waiting has a higher priority so record that a\r
 766                                                 context switch is required. */\r
 767                                                 *pxHigherPriorityTaskWoken = pdTRUE;\r
 768                                         }\r
 769                                 }\r
 770                         }\r
 771                         else\r
 772                         {\r
 773                                 /* Increment the lock count so the task that unlocks the queue\r
 774                                 knows that data was posted while it was locked. */\r
 775                                 ++( pxQueue->xTxLock );\r
 776                         }\r
 777 \r
 778                         xReturn = pdPASS;\r
 779                 }\r
 780                 else\r
 781                 {\r
 782                         traceQUEUE_SEND_FROM_ISR_FAILED( pxQueue );\r
 783                         xReturn = errQUEUE_FULL;\r
 784                 }\r
 785         }\r
 786         portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );\r
 787 \r
 788         return xReturn;\r
 789 }\r
 790 /*-----------------------------------------------------------*/\r
 791 \r
 792 signed portBASE_TYPE xQueueGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking )\r
 793 {\r
 794 signed portBASE_TYPE xEntryTimeSet = pdFALSE;\r
 795 xTimeOutType xTimeOut;\r
 796 signed portCHAR *pcOriginalReadPosition;\r
 797 \r
 798         for( ;; )\r
 799         {\r
 800                 taskENTER_CRITICAL();\r
 801                 {\r
 802                         if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )\r
 803                         {\r
 804                                 /* Remember our read position in case we are just peeking. */\r
 805                                 pcOriginalReadPosition = pxQueue->pcReadFrom;\r
 806 \r
 807                                 prvCopyDataFromQueue( pxQueue, pvBuffer );\r
 808 \r
 809                                 if( xJustPeeking == pdFALSE )\r
 810                                 {\r
 811                                         traceQUEUE_RECEIVE( pxQueue );\r
 812 \r
 813                                         /* We are actually removing data. */\r
 814                                         --( pxQueue->uxMessagesWaiting );\r
 815 \r
 816                                         #if ( configUSE_MUTEXES == 1 )\r
 817                                         {\r
 818                                                 if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
 819                                                 {\r
 820                                                         /* Record the information required to implement\r
 821                                                         priority inheritance should it become necessary. */\r
 822                                                         pxQueue->pxMutexHolder = xTaskGetCurrentTaskHandle();\r
 823                                                 }\r
 824                                         }\r
 825                                         #endif\r
 826 \r
 827                                         if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) == pdFALSE )\r
 828                                         {\r
 829                                                 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) == pdTRUE )\r
 830                                                 {\r
 831                                                         taskYIELD();\r
 832                                                 }\r
 833                                         }\r
 834                                 }\r
 835                                 else\r
 836                                 {\r
 837                                         traceQUEUE_PEEK( pxQueue );\r
 838 \r
 839                                         /* We are not removing the data, so reset our read\r
 840                                         pointer. */\r
 841                                         pxQueue->pcReadFrom = pcOriginalReadPosition;\r
 842 \r
 843                                         /* The data is being left in the queue, so see if there are\r
 844                                         any other tasks waiting for the data. */\r
 845                                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )\r
 846                                         {\r
 847                                                 /* Tasks that are removed from the event list will get added to\r
 848                                                 the pending ready list as the scheduler is still suspended. */\r
 849                                                 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
 850                                                 {\r
 851                                                         /* The task waiting has a higher priority than this task. */\r
 852                                                         taskYIELD();\r
 853                                                 }\r
 854                                         }\r
 855 \r
 856                                 }\r
 857 \r
 858                                 taskEXIT_CRITICAL();\r
 859                                 return pdPASS;\r
 860                         }\r
 861                         else\r
 862                         {\r
 863                                 if( xTicksToWait == ( portTickType ) 0 )\r
 864                                 {\r
 865                                         taskEXIT_CRITICAL();\r
 866                                         return errQUEUE_EMPTY;\r
 867                                 }\r
 868                                 else if( xEntryTimeSet == pdFALSE )\r
 869                                 {\r
 870                                         vTaskSetTimeOutState( &xTimeOut );\r
 871                                         xEntryTimeSet = pdTRUE;\r
 872                                 }\r
 873                         }\r
 874                 }\r
 875                 taskEXIT_CRITICAL();\r
 876 \r
 877                 vTaskSuspendAll();\r
 878                 prvLockQueue( pxQueue );\r
 879 \r
 880                 if( prvIsQueueEmpty( pxQueue ) )\r
 881                 {\r
 882                 /* Need to call xTaskCheckForTimeout again as time could\r
 883                 have passed since it was last called if this is not the\r
 884                 first time around this loop. */\r
 885                         if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )\r
 886                         {\r
 887                                 traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );\r
 888 \r
 889                                 #if ( configUSE_MUTEXES == 1 )\r
 890                                 {\r
 891                                         if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
 892                                         {\r
 893                                                 portENTER_CRITICAL();\r
 894                                                         vTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );\r
 895                                                 portEXIT_CRITICAL();\r
 896                                         }\r
 897                                 }\r
 898                                 #endif\r
 899 \r
 900                                 vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );\r
 901                                 prvUnlockQueue( pxQueue );\r
 902                                 if( !xTaskResumeAll() )\r
 903                                 {\r
 904                                         taskYIELD();\r
 905                                 }\r
 906                         }\r
 907                         else\r
 908                         {\r
 909                                 prvUnlockQueue( pxQueue );\r
 910                                 ( void ) xTaskResumeAll();\r
 911                                 return errQUEUE_EMPTY;\r
 912                         }\r
 913                 }\r
 914                 else\r
 915                 {\r
 916                         prvUnlockQueue( pxQueue );\r
 917                         ( void ) xTaskResumeAll();\r
 918                 }\r
 919         }\r
 920 }\r
 921 /*-----------------------------------------------------------*/\r
 922 \r
 923 signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void * const pvBuffer, signed portBASE_TYPE *pxTaskWoken )\r
 924 {\r
 925 signed portBASE_TYPE xReturn;\r
 926 unsigned portBASE_TYPE uxSavedInterruptStatus;\r
 927 \r
 928         uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();\r
 929         {\r
 930                 /* We cannot block from an ISR, so check there is data available. */\r
 931                 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )\r
 932                 {\r
 933                         traceQUEUE_RECEIVE_FROM_ISR( pxQueue );\r
 934 \r
 935                         prvCopyDataFromQueue( pxQueue, pvBuffer );\r
 936                         --( pxQueue->uxMessagesWaiting );\r
 937 \r
 938                         /* If the queue is locked we will not modify the event list.  Instead\r
 939                         we update the lock count so the task that unlocks the queue will know\r
 940                         that an ISR has removed data while the queue was locked. */\r
 941                         if( pxQueue->xRxLock == queueUNLOCKED )\r
 942                         {\r
 943                                 if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )\r
 944                                 {\r
 945                                         if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
 946                                         {\r
 947                                                 /* The task waiting has a higher priority than us so\r
 948                                                 force a context switch. */\r
 949                                                 *pxTaskWoken = pdTRUE;\r
 950                                         }\r
 951                                 }\r
 952                         }\r
 953                         else\r
 954                         {\r
 955                                 /* Increment the lock count so the task that unlocks the queue\r
 956                                 knows that data was removed while it was locked. */\r
 957                                 ++( pxQueue->xRxLock );\r
 958                         }\r
 959 \r
 960                         xReturn = pdPASS;\r
 961                 }\r
 962                 else\r
 963                 {\r
 964                         xReturn = pdFAIL;\r
 965                         traceQUEUE_RECEIVE_FROM_ISR_FAILED( pxQueue );\r
 966                 }\r
 967         }\r
 968         portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );\r
 969 \r
 970         return xReturn;\r
 971 }\r
 972 /*-----------------------------------------------------------*/\r
 973 \r
 974 unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle pxQueue )\r
 975 {\r
 976 unsigned portBASE_TYPE uxReturn;\r
 977 \r
 978         taskENTER_CRITICAL();\r
 979                 uxReturn = pxQueue->uxMessagesWaiting;\r
 980         taskEXIT_CRITICAL();\r
 981 \r
 982         return uxReturn;\r
 983 }\r
 984 /*-----------------------------------------------------------*/\r
 985 \r
 986 unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle pxQueue )\r
 987 {\r
 988 unsigned portBASE_TYPE uxReturn;\r
 989 \r
 990         uxReturn = pxQueue->uxMessagesWaiting;\r
 991 \r
 992         return uxReturn;\r
 993 }\r
 994 /*-----------------------------------------------------------*/\r
 995 \r
 996 void vQueueDelete( xQueueHandle pxQueue )\r
 997 {\r
 998         traceQUEUE_DELETE( pxQueue );\r
 999         vQueueUnregisterQueue( pxQueue );\r
1000         vPortFree( pxQueue->pcHead );\r
1001         vPortFree( pxQueue );\r
1002 }\r
1003 /*-----------------------------------------------------------*/\r
1004 \r
1005 static void prvCopyDataToQueue( xQUEUE *pxQueue, const void *pvItemToQueue, portBASE_TYPE xPosition )\r
1006 {\r
1007         if( pxQueue->uxItemSize == ( unsigned portBASE_TYPE ) 0 )\r
1008         {\r
1009                 #if ( configUSE_MUTEXES == 1 )\r
1010                 {\r
1011                         if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )\r
1012                         {\r
1013                                 /* The mutex is no longer being held. */\r
1014                                 vTaskPriorityDisinherit( ( void * ) pxQueue->pxMutexHolder );\r
1015                 pxQueue->pxMutexHolder = NULL;\r
1016                         }\r
1017                 }\r
1018                 #endif\r
1019         }\r
1020         else if( xPosition == queueSEND_TO_BACK )\r
1021         {\r
1022                 memcpy( ( void * ) pxQueue->pcWriteTo, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize );\r
1023                 pxQueue->pcWriteTo += pxQueue->uxItemSize;\r
1024                 if( pxQueue->pcWriteTo >= pxQueue->pcTail )\r
1025                 {\r
1026                         pxQueue->pcWriteTo = pxQueue->pcHead;\r
1027                 }\r
1028         }\r
1029         else\r
1030         {\r
1031                 memcpy( ( void * ) pxQueue->pcReadFrom, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize );\r
1032                 pxQueue->pcReadFrom -= pxQueue->uxItemSize;\r
1033                 if( pxQueue->pcReadFrom < pxQueue->pcHead )\r
1034                 {\r
1035                         pxQueue->pcReadFrom = ( pxQueue->pcTail - pxQueue->uxItemSize );\r
1036                 }\r
1037         }\r
1038 \r
1039         ++( pxQueue->uxMessagesWaiting );\r
1040 }\r
1041 /*-----------------------------------------------------------*/\r
1042 \r
1043 static void prvCopyDataFromQueue( xQUEUE * const pxQueue, const void *pvBuffer )\r
1044 {\r
1045         if( pxQueue->uxQueueType != queueQUEUE_IS_MUTEX )\r
1046         {\r
1047                 pxQueue->pcReadFrom += pxQueue->uxItemSize;\r
1048                 if( pxQueue->pcReadFrom >= pxQueue->pcTail )\r
1049                 {\r
1050                         pxQueue->pcReadFrom = pxQueue->pcHead;\r
1051                 }\r
1052                 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );\r
1053         }\r
1054 }\r
1055 /*-----------------------------------------------------------*/\r
1056 \r
1057 static void prvUnlockQueue( xQueueHandle pxQueue )\r
1058 {\r
1059         /* THIS FUNCTION MUST BE CALLED WITH THE SCHEDULER SUSPENDED. */\r
1060 \r
1061         /* The lock counts contains the number of extra data items placed or\r
1062         removed from the queue while the queue was locked.  When a queue is\r
1063         locked items can be added or removed, but the event lists cannot be\r
1064         updated. */\r
1065         taskENTER_CRITICAL();\r
1066         {\r
1067                 /* See if data was added to the queue while it was locked. */\r
1068                 while( pxQueue->xTxLock > queueLOCKED_UNMODIFIED )\r
1069                 {\r
1070                         /* Data was posted while the queue was locked.  Are any tasks\r
1071                         blocked waiting for data to become available? */\r
1072                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )\r
1073                         {\r
1074                                 /* Tasks that are removed from the event list will get added to\r
1075                                 the pending ready list as the scheduler is still suspended. */\r
1076                                 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
1077                                 {\r
1078                                         /* The task waiting has a higher priority so record that a\r
1079                                         context switch is required. */\r
1080                                         vTaskMissedYield();\r
1081                                 }\r
1082 \r
1083                                 --( pxQueue->xTxLock );\r
1084                         }\r
1085                         else\r
1086                         {\r
1087                                 break;\r
1088                         }\r
1089                 }\r
1090 \r
1091                 pxQueue->xTxLock = queueUNLOCKED;\r
1092         }\r
1093         taskEXIT_CRITICAL();\r
1094 \r
1095         /* Do the same for the Rx lock. */\r
1096         taskENTER_CRITICAL();\r
1097         {\r
1098                 while( pxQueue->xRxLock > queueLOCKED_UNMODIFIED )\r
1099                 {\r
1100                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )\r
1101                         {\r
1102                                 if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
1103                                 {\r
1104                                         vTaskMissedYield();\r
1105                                 }\r
1106 \r
1107                                 --( pxQueue->xRxLock );\r
1108                         }\r
1109                         else\r
1110                         {\r
1111                                 break;\r
1112                         }\r
1113                 }\r
1114 \r
1115                 pxQueue->xRxLock = queueUNLOCKED;\r
1116         }\r
1117         taskEXIT_CRITICAL();\r
1118 }\r
1119 /*-----------------------------------------------------------*/\r
1120 \r
1121 static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue )\r
1122 {\r
1123 signed portBASE_TYPE xReturn;\r
1124 \r
1125         taskENTER_CRITICAL();\r
1126                 xReturn = ( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 );\r
1127         taskEXIT_CRITICAL();\r
1128 \r
1129         return xReturn;\r
1130 }\r
1131 /*-----------------------------------------------------------*/\r
1132 \r
1133 signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle pxQueue )\r
1134 {\r
1135 signed portBASE_TYPE xReturn;\r
1136 \r
1137         xReturn = ( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 );\r
1138 \r
1139         return xReturn;\r
1140 }\r
1141 /*-----------------------------------------------------------*/\r
1142 \r
1143 static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue )\r
1144 {\r
1145 signed portBASE_TYPE xReturn;\r
1146 \r
1147         taskENTER_CRITICAL();\r
1148                 xReturn = ( pxQueue->uxMessagesWaiting == pxQueue->uxLength );\r
1149         taskEXIT_CRITICAL();\r
1150 \r
1151         return xReturn;\r
1152 }\r
1153 /*-----------------------------------------------------------*/\r
1154 \r
1155 signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle pxQueue )\r
1156 {\r
1157 signed portBASE_TYPE xReturn;\r
1158 \r
1159         xReturn = ( pxQueue->uxMessagesWaiting == pxQueue->uxLength );\r
1160 \r
1161         return xReturn;\r
1162 }\r
1163 /*-----------------------------------------------------------*/\r
1164 \r
1165 #if configUSE_CO_ROUTINES == 1\r
1166 signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait )\r
1167 {\r
1168 signed portBASE_TYPE xReturn;\r
1169 \r
1170         /* If the queue is already full we may have to block.  A critical section\r
1171         is required to prevent an interrupt removing something from the queue\r
1172         between the check to see if the queue is full and blocking on the queue. */\r
1173         portDISABLE_INTERRUPTS();\r
1174         {\r
1175                 if( prvIsQueueFull( pxQueue ) )\r
1176                 {\r
1177                         /* The queue is full - do we want to block or just leave without\r
1178                         posting? */\r
1179                         if( xTicksToWait > ( portTickType ) 0 )\r
1180                         {\r
1181                                 /* As this is called from a coroutine we cannot block directly, but\r
1182                                 return indicating that we need to block. */\r
1183                                 vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToSend ) );\r
1184                                 portENABLE_INTERRUPTS();\r
1185                                 return errQUEUE_BLOCKED;\r
1186                         }\r
1187                         else\r
1188                         {\r
1189                                 portENABLE_INTERRUPTS();\r
1190                                 return errQUEUE_FULL;\r
1191                         }\r
1192                 }\r
1193         }\r
1194         portENABLE_INTERRUPTS();\r
1195 \r
1196         portNOP();\r
1197 \r
1198         portDISABLE_INTERRUPTS();\r
1199         {\r
1200                 if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )\r
1201                 {\r
1202                         /* There is room in the queue, copy the data into the queue. */\r
1203                         prvCopyDataToQueue( pxQueue, pvItemToQueue, queueSEND_TO_BACK );\r
1204                         xReturn = pdPASS;\r
1205 \r
1206                         /* Were any co-routines waiting for data to become available? */\r
1207                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )\r
1208                         {\r
1209                                 /* In this instance the co-routine could be placed directly\r
1210                                 into the ready list as we are within a critical section.\r
1211                                 Instead the same pending ready list mechanism is used as if\r
1212                                 the event were caused from within an interrupt. */\r
1213                                 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
1214                                 {\r
1215                                         /* The co-routine waiting has a higher priority so record\r
1216                                         that a yield might be appropriate. */\r
1217                                         xReturn = errQUEUE_YIELD;\r
1218                                 }\r
1219                         }\r
1220                 }\r
1221                 else\r
1222                 {\r
1223                         xReturn = errQUEUE_FULL;\r
1224                 }\r
1225         }\r
1226         portENABLE_INTERRUPTS();\r
1227 \r
1228         return xReturn;\r
1229 }\r
1230 #endif\r
1231 /*-----------------------------------------------------------*/\r
1232 \r
1233 #if configUSE_CO_ROUTINES == 1\r
1234 signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait )\r
1235 {\r
1236 signed portBASE_TYPE xReturn;\r
1237 \r
1238         /* If the queue is already empty we may have to block.  A critical section\r
1239         is required to prevent an interrupt adding something to the queue\r
1240         between the check to see if the queue is empty and blocking on the queue. */\r
1241         portDISABLE_INTERRUPTS();\r
1242         {\r
1243                 if( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 )\r
1244                 {\r
1245                         /* There are no messages in the queue, do we want to block or just\r
1246                         leave with nothing? */\r
1247                         if( xTicksToWait > ( portTickType ) 0 )\r
1248                         {\r
1249                                 /* As this is a co-routine we cannot block directly, but return\r
1250                                 indicating that we need to block. */\r
1251                                 vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToReceive ) );\r
1252                                 portENABLE_INTERRUPTS();\r
1253                                 return errQUEUE_BLOCKED;\r
1254                         }\r
1255                         else\r
1256                         {\r
1257                                 portENABLE_INTERRUPTS();\r
1258                                 return errQUEUE_FULL;\r
1259                         }\r
1260                 }\r
1261         }\r
1262         portENABLE_INTERRUPTS();\r
1263 \r
1264         portNOP();\r
1265 \r
1266         portDISABLE_INTERRUPTS();\r
1267         {\r
1268                 if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )\r
1269                 {\r
1270                         /* Data is available from the queue. */\r
1271                         pxQueue->pcReadFrom += pxQueue->uxItemSize;\r
1272                         if( pxQueue->pcReadFrom >= pxQueue->pcTail )\r
1273                         {\r
1274                                 pxQueue->pcReadFrom = pxQueue->pcHead;\r
1275                         }\r
1276                         --( pxQueue->uxMessagesWaiting );\r
1277                         memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );\r
1278 \r
1279                         xReturn = pdPASS;\r
1280 \r
1281                         /* Were any co-routines waiting for space to become available? */\r
1282                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )\r
1283                         {\r
1284                                 /* In this instance the co-routine could be placed directly\r
1285                                 into the ready list as we are within a critical section.\r
1286                                 Instead the same pending ready list mechanism is used as if\r
1287                                 the event were caused from within an interrupt. */\r
1288                                 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
1289                                 {\r
1290                                         xReturn = errQUEUE_YIELD;\r
1291                                 }\r
1292                         }\r
1293                 }\r
1294                 else\r
1295                 {\r
1296                         xReturn = pdFAIL;\r
1297                 }\r
1298         }\r
1299         portENABLE_INTERRUPTS();\r
1300 \r
1301         return xReturn;\r
1302 }\r
1303 #endif\r
1304 /*-----------------------------------------------------------*/\r
1305 \r
1306 \r
1307 \r
1308 #if configUSE_CO_ROUTINES == 1\r
1309 signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken )\r
1310 {\r
1311         /* Cannot block within an ISR so if there is no space on the queue then\r
1312         exit without doing anything. */\r
1313         if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )\r
1314         {\r
1315                 prvCopyDataToQueue( pxQueue, pvItemToQueue, queueSEND_TO_BACK );\r
1316 \r
1317                 /* We only want to wake one co-routine per ISR, so check that a\r
1318                 co-routine has not already been woken. */\r
1319                 if( !xCoRoutinePreviouslyWoken )\r
1320                 {\r
1321                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )\r
1322                         {\r
1323                                 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )\r
1324                                 {\r
1325                                         return pdTRUE;\r
1326                                 }\r
1327                         }\r
1328                 }\r
1329         }\r
1330 \r
1331         return xCoRoutinePreviouslyWoken;\r
1332 }\r
1333 #endif\r
1334 /*-----------------------------------------------------------*/\r
1335 \r
1336 #if configUSE_CO_ROUTINES == 1\r
1337 signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxCoRoutineWoken )\r
1338 {\r
1339 signed portBASE_TYPE xReturn;\r
1340 \r
1341         /* We cannot block from an ISR, so check there is data available. If\r
1342         not then just leave without doing anything. */\r
1343         if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )\r
1344         {\r
1345                 /* Copy the data from the queue. */\r
1346                 pxQueue->pcReadFrom += pxQueue->uxItemSize;\r
1347                 if( pxQueue->pcReadFrom >= pxQueue->pcTail )\r
1348                 {\r
1349                         pxQueue->pcReadFrom = pxQueue->pcHead;\r
1350                 }\r
1351                 --( pxQueue->uxMessagesWaiting );\r
1352                 memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );\r
1353 \r
1354                 if( !( *pxCoRoutineWoken ) )\r
1355                 {\r
1356                         if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )\r
1357                         {\r
1358                                 if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )\r
1359                                 {\r
1360                                         *pxCoRoutineWoken = pdTRUE;\r
1361                                 }\r
1362                         }\r
1363                 }\r
1364 \r
1365                 xReturn = pdPASS;\r
1366         }\r
1367         else\r
1368         {\r
1369                 xReturn = pdFAIL;\r
1370         }\r
1371 \r
1372         return xReturn;\r
1373 }\r
1374 #endif\r
1375 /*-----------------------------------------------------------*/\r
1376 \r
1377 #if configQUEUE_REGISTRY_SIZE > 0\r
1378 \r
1379         void vQueueAddToRegistry( xQueueHandle xQueue, signed portCHAR *pcQueueName )\r
1380         {\r
1381         unsigned portBASE_TYPE ux;\r
1382 \r
1383                 /* See if there is an empty space in the registry.  A NULL name denotes\r
1384                 a free slot. */\r
1385                 for( ux = 0; ux < configQUEUE_REGISTRY_SIZE; ux++ )\r
1386                 {\r
1387                         if( xQueueRegistry[ ux ].pcQueueName == NULL )\r
1388                         {\r
1389                                 /* Store the information on this queue. */\r
1390                                 xQueueRegistry[ ux ].pcQueueName = pcQueueName;\r
1391                                 xQueueRegistry[ ux ].xHandle = xQueue;\r
1392                                 break;\r
1393                         }\r
1394                 }\r
1395         }\r
1396 \r
1397 #endif\r
1398         /*-----------------------------------------------------------*/\r
1399 \r
1400 #if configQUEUE_REGISTRY_SIZE > 0\r
1401 \r
1402         static void vQueueUnregisterQueue( xQueueHandle xQueue )\r
1403         {\r
1404         unsigned portBASE_TYPE ux;\r
1405 \r
1406                 /* See if the handle of the queue being unregistered in actually in the\r
1407                 registry. */\r
1408                 for( ux = 0; ux < configQUEUE_REGISTRY_SIZE; ux++ )\r
1409                 {\r
1410                         if( xQueueRegistry[ ux ].xHandle == xQueue )\r
1411                         {\r
1412                                 /* Set the name to NULL to show that this slot if free again. */\r
1413                                 xQueueRegistry[ ux ].pcQueueName = NULL;\r
1414                                 break;\r
1415                         }\r
1416                 }\r
1417         }\r
1418 \r
1419 #endif\r
1420 \r