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Diffstat (limited to 'openpicc/os/core/queue.c')
| -rw-r--r-- | openpicc/os/core/queue.c | 1002 |
1 files changed, 1002 insertions, 0 deletions
diff --git a/openpicc/os/core/queue.c b/openpicc/os/core/queue.c new file mode 100644 index 0000000..c2f08cb --- /dev/null +++ b/openpicc/os/core/queue.c @@ -0,0 +1,1002 @@ +/* + FreeRTOS.org V4.2.1 - Copyright (C) 2003-2007 Richard Barry. + + This file is part of the FreeRTOS.org distribution. + + FreeRTOS.org is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + FreeRTOS.org is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with FreeRTOS.org; if not, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + + A special exception to the GPL can be applied should you wish to distribute + a combined work that includes FreeRTOS.org, without being obliged to provide + the source code for any proprietary components. See the licensing section + of http://www.FreeRTOS.org for full details of how and when the exception + can be applied. + + *************************************************************************** + See http://www.FreeRTOS.org for documentation, latest information, license + and contact details. Please ensure to read the configuration and relevant + port sections of the online documentation. + + Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along + with commercial development and support options. + *************************************************************************** +*/ + +/* +Changes from V1.01 + + + More use of 8bit data types. + + Function name prefixes changed where the data type returned has changed. + +Changed from V2.0.0 + + + Added the queue locking mechanism and make more use of the scheduler + suspension feature to minimise the time interrupts have to be disabled + when accessing a queue. + +Changed from V2.2.0 + + + Explicit use of 'signed' qualifier on portCHAR types added. + +Changes from V3.0.0 + + + API changes as described on the FreeRTOS.org WEB site. + +Changes from V3.2.3 + + + Added the queue functions that can be used from co-routines. + +Changes from V4.0.5 + + + Added a loop within xQueueSend() and xQueueReceive() to prevent the + functions exiting when a block time remains and the function has + not completed. + +Changes from V4.1.2: + + + BUG FIX: Removed the call to prvIsQueueEmpty from within xQueueCRReceive + as it exited with interrupts enabled. Thanks Paul Katz. + +Changes from V4.1.3: + + + Modified xQueueSend() and xQueueReceive() to handle the (very unlikely) + case whereby a task unblocking due to a temporal event can remove/send an + item from/to a queue when a higher priority task is still blocked on the + queue. This modification is a result of the SafeRTOS testing. +*/ + +#include <stdlib.h> +#include <string.h> +#include "FreeRTOS.h" +#include "task.h" +#include "croutine.h" + +/*----------------------------------------------------------- + * PUBLIC LIST API documented in list.h + *----------------------------------------------------------*/ + +/* Constants used with the cRxLock and cTxLock structure members. */ +#define queueUNLOCKED ( ( signed portBASE_TYPE ) -1 ) +#define queueERRONEOUS_UNBLOCK ( -1 ) + +/* + * Definition of the queue used by the scheduler. + * Items are queued by copy, not reference. + */ +typedef struct QueueDefinition +{ + signed portCHAR *pcHead; /*< Points to the beginning of the queue storage area. */ + 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. */ + + signed portCHAR *pcWriteTo; /*< Points to the free next place in the storage area. */ + signed portCHAR *pcReadFrom; /*< Points to the last place that a queued item was read from. */ + + xList xTasksWaitingToSend; /*< List of tasks that are blocked waiting to post onto this queue. Stored in priority order. */ + xList xTasksWaitingToReceive; /*< List of tasks that are blocked waiting to read from this queue. Stored in priority order. */ + + unsigned portBASE_TYPE uxMessagesWaiting; /*< The number of items currently in the queue. */ + unsigned portBASE_TYPE uxLength; /*< The length of the queue defined as the number of items it will hold, not the number of bytes. */ + unsigned portBASE_TYPE uxItemSize; /*< The size of each items that the queue will hold. */ + + 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. */ + 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. */ +} xQUEUE; +/*-----------------------------------------------------------*/ + +/* + * Inside this file xQueueHandle is a pointer to a xQUEUE structure. + * To keep the definition private the API header file defines it as a + * pointer to void. + */ +typedef xQUEUE *xQueueHandle; + +/* + * Prototypes for public functions are included here so we don't have to + * include the API header file (as it defines xQueueHandle differently). These + * functions are documented in the API header file. + */ +xQueueHandle xQueueCreate (unsigned portBASE_TYPE uxQueueLength, + unsigned portBASE_TYPE uxItemSize); +signed portBASE_TYPE xQueueSend (xQueueHandle xQueue, + const void *pvItemToQueue, + portTickType xTicksToWait); +unsigned portBASE_TYPE uxQueueMessagesWaiting (xQueueHandle pxQueue); +void vQueueDelete (xQueueHandle xQueue); +signed portBASE_TYPE xQueueSendFromISR (xQueueHandle pxQueue, + const void *pvItemToQueue, + signed portBASE_TYPE + xTaskPreviouslyWoken); +signed portBASE_TYPE xQueueReceive (xQueueHandle pxQueue, void *pvBuffer, + portTickType xTicksToWait); +signed portBASE_TYPE xQueueReceiveFromISR (xQueueHandle pxQueue, + void *pvBuffer, + signed portBASE_TYPE * + pxTaskWoken); + +#if configUSE_CO_ROUTINES == 1 +signed portBASE_TYPE xQueueCRSendFromISR (xQueueHandle pxQueue, + const void *pvItemToQueue, + signed portBASE_TYPE + xCoRoutinePreviouslyWoken); +signed portBASE_TYPE xQueueCRReceiveFromISR (xQueueHandle pxQueue, + void *pvBuffer, + signed portBASE_TYPE * + pxTaskWoken); +signed portBASE_TYPE xQueueCRSend (xQueueHandle pxQueue, + const void *pvItemToQueue, + portTickType xTicksToWait); +signed portBASE_TYPE xQueueCRReceive (xQueueHandle pxQueue, void *pvBuffer, + portTickType xTicksToWait); +#endif + +/* + * Unlocks a queue locked by a call to prvLockQueue. Locking a queue does not + * prevent an ISR from adding or removing items to the queue, but does prevent + * an ISR from removing tasks from the queue event lists. If an ISR finds a + * queue is locked it will instead increment the appropriate queue lock count + * to indicate that a task may require unblocking. When the queue in unlocked + * these lock counts are inspected, and the appropriate action taken. + */ +static void prvUnlockQueue (xQueueHandle pxQueue); + +/* + * Uses a critical section to determine if there is any data in a queue. + * + * @return pdTRUE if the queue contains no items, otherwise pdFALSE. + */ +static signed portBASE_TYPE prvIsQueueEmpty (const xQueueHandle pxQueue); + +/* + * Uses a critical section to determine if there is any space in a queue. + * + * @return pdTRUE if there is no space, otherwise pdFALSE; + */ +static signed portBASE_TYPE prvIsQueueFull (const xQueueHandle pxQueue); + +/* + * Macro that copies an item into the queue. This is done by copying the item + * byte for byte, not by reference. Updates the queue state to ensure it's + * integrity after the copy. + */ +#define prvCopyQueueData( pxQueue, pvItemToQueue ) \ +{ \ + memcpy( ( void * ) pxQueue->pcWriteTo, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize ); \ + ++( pxQueue->uxMessagesWaiting ); \ + pxQueue->pcWriteTo += pxQueue->uxItemSize; \ + if( pxQueue->pcWriteTo >= pxQueue->pcTail ) \ + { \ + pxQueue->pcWriteTo = pxQueue->pcHead; \ + } \ +} +/*-----------------------------------------------------------*/ + +/* + * Macro to mark a queue as locked. Locking a queue prevents an ISR from + * accessing the queue event lists. + */ +#define prvLockQueue( pxQueue ) \ +{ \ + taskENTER_CRITICAL(); \ + ++( pxQueue->xRxLock ); \ + ++( pxQueue->xTxLock ); \ + taskEXIT_CRITICAL(); \ +} +/*-----------------------------------------------------------*/ + + +/*----------------------------------------------------------- + * PUBLIC QUEUE MANAGEMENT API documented in queue.h + *----------------------------------------------------------*/ + +xQueueHandle +xQueueCreate (unsigned portBASE_TYPE uxQueueLength, + unsigned portBASE_TYPE uxItemSize) +{ + xQUEUE *pxNewQueue; + size_t xQueueSizeInBytes; + + /* Allocate the new queue structure. */ + if (uxQueueLength > (unsigned portBASE_TYPE) 0) + { + pxNewQueue = (xQUEUE *) pvPortMalloc (sizeof (xQUEUE)); + if (pxNewQueue != NULL) + { + /* Create the list of pointers to queue items. The queue is one byte + longer than asked for to make wrap checking easier/faster. */ + xQueueSizeInBytes = + (size_t) (uxQueueLength * uxItemSize) + (size_t) 1; + + pxNewQueue->pcHead = + (signed portCHAR *) pvPortMalloc (xQueueSizeInBytes); + if (pxNewQueue->pcHead != NULL) + { + /* Initialise the queue members as described above where the + queue type is defined. */ + pxNewQueue->pcTail = + pxNewQueue->pcHead + (uxQueueLength * uxItemSize); + pxNewQueue->uxMessagesWaiting = 0; + pxNewQueue->pcWriteTo = pxNewQueue->pcHead; + pxNewQueue->pcReadFrom = + pxNewQueue->pcHead + ((uxQueueLength - 1) * uxItemSize); + pxNewQueue->uxLength = uxQueueLength; + pxNewQueue->uxItemSize = uxItemSize; + pxNewQueue->xRxLock = queueUNLOCKED; + pxNewQueue->xTxLock = queueUNLOCKED; + + /* Likewise ensure the event queues start with the correct state. */ + vListInitialise (&(pxNewQueue->xTasksWaitingToSend)); + vListInitialise (&(pxNewQueue->xTasksWaitingToReceive)); + + return pxNewQueue; + } + else + { + vPortFree (pxNewQueue); + } + } + } + + /* Will only reach here if we could not allocate enough memory or no memory + was required. */ + return NULL; +} + +/*-----------------------------------------------------------*/ + +signed portBASE_TYPE +xQueueSend (xQueueHandle pxQueue, const void *pvItemToQueue, + portTickType xTicksToWait) +{ + signed portBASE_TYPE xReturn = pdPASS; + xTimeOutType xTimeOut; + + /* Make sure other tasks do not access the queue. */ + vTaskSuspendAll (); + + /* Capture the current time status for future reference. */ + vTaskSetTimeOutState (&xTimeOut); + + /* It is important that this is the only thread/ISR that modifies the + ready or delayed lists until xTaskResumeAll() is called. Places where + the ready/delayed lists are modified include: + + + vTaskDelay() - Nothing can call vTaskDelay as the scheduler is + suspended, vTaskDelay() cannot be called from an ISR. + + vTaskPrioritySet() - Has a critical section around the access. + + vTaskSwitchContext() - This will not get executed while the scheduler + is suspended. + + prvCheckDelayedTasks() - This will not get executed while the + scheduler is suspended. + + xTaskCreate() - Has a critical section around the access. + + vTaskResume() - Has a critical section around the access. + + xTaskResumeAll() - Has a critical section around the access. + + xTaskRemoveFromEventList - Checks to see if the scheduler is + suspended. If so then the TCB being removed from the event is + removed from the event and added to the xPendingReadyList. + */ + + /* Make sure interrupts do not access the queue event list. */ + prvLockQueue (pxQueue); + + /* It is important that interrupts to not access the event list of the + queue being modified here. Places where the event list is modified + include: + + + xQueueSendFromISR(). This checks the lock on the queue to see if + it has access. If the queue is locked then the Tx lock count is + incremented to signify that a task waiting for data can be made ready + once the queue lock is removed. If the queue is not locked then + a task can be moved from the event list, but will not be removed + from the delayed list or placed in the ready list until the scheduler + is unlocked. + + + xQueueReceiveFromISR(). As per xQueueSendFromISR(). + */ + + /* If the queue is already full we may have to block. */ + do + { + if (prvIsQueueFull (pxQueue)) + { + /* The queue is full - do we want to block or just leave without + posting? */ + if (xTicksToWait > (portTickType) 0) + { + /* We are going to place ourselves on the xTasksWaitingToSend event + list, and will get woken should the delay expire, or space become + available on the queue. + + As detailed above we do not require mutual exclusion on the event + list as nothing else can modify it or the ready lists while we + have the scheduler suspended and queue locked. + + It is possible that an ISR has removed data from the queue since we + checked if any was available. If this is the case then the data + will have been copied from the queue, and the queue variables + updated, but the event list will not yet have been checked to see if + anything is waiting as the queue is locked. */ + vTaskPlaceOnEventList (&(pxQueue->xTasksWaitingToSend), + xTicksToWait); + + /* Force a context switch now as we are blocked. We can do + this from within a critical section as the task we are + switching to has its own context. When we return here (i.e. we + unblock) we will leave the critical section as normal. + + It is possible that an ISR has caused an event on an unrelated and + unlocked queue. If this was the case then the event list for that + queue will have been updated but the ready lists left unchanged - + instead the readied task will have been added to the pending ready + list. */ + taskENTER_CRITICAL (); + { + /* We can safely unlock the queue and scheduler here as + interrupts are disabled. We must not yield with anything + locked, but we can yield from within a critical section. + + Tasks that have been placed on the pending ready list cannot + be tasks that are waiting for events on this queue. See + in comment xTaskRemoveFromEventList(). */ + prvUnlockQueue (pxQueue); + + /* Resuming the scheduler may cause a yield. If so then there + is no point yielding again here. */ + if (!xTaskResumeAll ()) + { + taskYIELD (); + } + + /* We want to check to see if the queue is still full + before leaving the critical section. This is to prevent + this task placing an item into the queue due to an + interrupt making space on the queue between critical + sections (when there might be a higher priority task + blocked on the queue that cannot run yet because the + scheduler gets suspended). */ + if (pxQueue->uxMessagesWaiting == pxQueue->uxLength) + { + /* We unblocked but there is no space in the queue, + we probably timed out. */ + xReturn = errQUEUE_FULL; + } + + /* Before leaving the critical section we have to ensure + exclusive access again. */ + vTaskSuspendAll (); + prvLockQueue (pxQueue); + } + taskEXIT_CRITICAL (); + } + } + + /* If xReturn is errQUEUE_FULL then we unblocked when the queue + was still full. Don't check it again now as it is possible that + an interrupt has removed an item from the queue since we left the + critical section and we don't want to write to the queue in case + there is a task of higher priority blocked waiting for space to + be available on the queue. If this is the case the higher priority + task will execute when the scheduler is unsupended. */ + if (xReturn != errQUEUE_FULL) + { + /* When we are here it is possible that we unblocked as space became + available on the queue. It is also possible that an ISR posted to the + queue since we left the critical section, so it may be that again there + is no space. This would only happen if a task and ISR post onto the + same queue. */ + taskENTER_CRITICAL (); + { + if (pxQueue->uxMessagesWaiting < pxQueue->uxLength) + { + /* There is room in the queue, copy the data into the queue. */ + prvCopyQueueData (pxQueue, pvItemToQueue); + xReturn = pdPASS; + + /* Update the TxLock count so prvUnlockQueue knows to check for + tasks waiting for data to become available in the queue. */ + ++(pxQueue->xTxLock); + } + else + { + xReturn = errQUEUE_FULL; + } + } + taskEXIT_CRITICAL (); + } + + if (xReturn == errQUEUE_FULL) + { + if (xTicksToWait > 0) + { + if (xTaskCheckForTimeOut (&xTimeOut, &xTicksToWait) == pdFALSE) + { + xReturn = queueERRONEOUS_UNBLOCK; + } + } + } + } + while (xReturn == queueERRONEOUS_UNBLOCK); + + prvUnlockQueue (pxQueue); + xTaskResumeAll (); + + return xReturn; +} + +/*-----------------------------------------------------------*/ + +signed portBASE_TYPE +xQueueSendFromISR (xQueueHandle pxQueue, const void *pvItemToQueue, + signed portBASE_TYPE xTaskPreviouslyWoken) +{ + /* Similar to xQueueSend, except we don't block if there is no room in the + queue. Also we don't directly wake a task that was blocked on a queue + read, instead we return a flag to say whether a context switch is required + or not (i.e. has a task with a higher priority than us been woken by this + post). */ + if (pxQueue->uxMessagesWaiting < pxQueue->uxLength) + { + prvCopyQueueData (pxQueue, pvItemToQueue); + + /* If the queue is locked we do not alter the event list. This will + be done when the queue is unlocked later. */ + if (pxQueue->xTxLock == queueUNLOCKED) + { + /* We only want to wake one task per ISR, so check that a task has + not already been woken. */ + if (!xTaskPreviouslyWoken) + { + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToReceive))) + { + if (xTaskRemoveFromEventList + (&(pxQueue->xTasksWaitingToReceive)) != pdFALSE) + { + /* The task waiting has a higher priority so record that a + context switch is required. */ + return pdTRUE; + } + } + } + } + else + { + /* Increment the lock count so the task that unlocks the queue + knows that data was posted while it was locked. */ + ++(pxQueue->xTxLock); + } + } + + return xTaskPreviouslyWoken; +} + +/*-----------------------------------------------------------*/ + +signed portBASE_TYPE +xQueueReceive (xQueueHandle pxQueue, void *pvBuffer, + portTickType xTicksToWait) +{ + signed portBASE_TYPE xReturn = pdTRUE; + xTimeOutType xTimeOut; + + /* This function is very similar to xQueueSend(). See comments within + xQueueSend() for a more detailed explanation. + + Make sure other tasks do not access the queue. */ + vTaskSuspendAll (); + + /* Capture the current time status for future reference. */ + vTaskSetTimeOutState (&xTimeOut); + + /* Make sure interrupts do not access the queue. */ + prvLockQueue (pxQueue); + + do + { + /* If there are no messages in the queue we may have to block. */ + if (prvIsQueueEmpty (pxQueue)) + { + /* There are no messages in the queue, do we want to block or just + leave with nothing? */ + if (xTicksToWait > (portTickType) 0) + { + vTaskPlaceOnEventList (&(pxQueue->xTasksWaitingToReceive), + xTicksToWait); + taskENTER_CRITICAL (); + { + prvUnlockQueue (pxQueue); + if (!xTaskResumeAll ()) + { + taskYIELD (); + } + + if (pxQueue->uxMessagesWaiting == (unsigned portBASE_TYPE) 0) + { + /* We unblocked but the queue is empty. We probably + timed out. */ + xReturn = errQUEUE_EMPTY; + } + + vTaskSuspendAll (); + prvLockQueue (pxQueue); + } + taskEXIT_CRITICAL (); + } + } + + if (xReturn != errQUEUE_EMPTY) + { + taskENTER_CRITICAL (); + { + if (pxQueue->uxMessagesWaiting > (unsigned portBASE_TYPE) 0) + { + pxQueue->pcReadFrom += pxQueue->uxItemSize; + if (pxQueue->pcReadFrom >= pxQueue->pcTail) + { + pxQueue->pcReadFrom = pxQueue->pcHead; + } + --(pxQueue->uxMessagesWaiting); + memcpy ((void *) pvBuffer, (void *) pxQueue->pcReadFrom, + (unsigned) pxQueue->uxItemSize); + + /* Increment the lock count so prvUnlockQueue knows to check for + tasks waiting for space to become available on the queue. */ + ++(pxQueue->xRxLock); + xReturn = pdPASS; + } + else + { + xReturn = errQUEUE_EMPTY; + } + } + taskEXIT_CRITICAL (); + } + + if (xReturn == errQUEUE_EMPTY) + { + if (xTicksToWait > 0) + { + if (xTaskCheckForTimeOut (&xTimeOut, &xTicksToWait) == pdFALSE) + { + xReturn = queueERRONEOUS_UNBLOCK; + } + } + } + } + while (xReturn == queueERRONEOUS_UNBLOCK); + + /* We no longer require exclusive access to the queue. */ + prvUnlockQueue (pxQueue); + xTaskResumeAll (); + + return xReturn; +} + +/*-----------------------------------------------------------*/ + +signed portBASE_TYPE +xQueueReceiveFromISR (xQueueHandle pxQueue, void *pvBuffer, + signed portBASE_TYPE * pxTaskWoken) +{ + signed portBASE_TYPE xReturn; + + /* We cannot block from an ISR, so check there is data available. */ + if (pxQueue->uxMessagesWaiting > (unsigned portBASE_TYPE) 0) + { + /* Copy the data from the queue. */ + pxQueue->pcReadFrom += pxQueue->uxItemSize; + if (pxQueue->pcReadFrom >= pxQueue->pcTail) + { + pxQueue->pcReadFrom = pxQueue->pcHead; + } + --(pxQueue->uxMessagesWaiting); + memcpy ((void *) pvBuffer, (void *) pxQueue->pcReadFrom, + (unsigned) pxQueue->uxItemSize); + + /* If the queue is locked we will not modify the event list. Instead + we update the lock count so the task that unlocks the queue will know + that an ISR has removed data while the queue was locked. */ + if (pxQueue->xRxLock == queueUNLOCKED) + { + /* We only want to wake one task per ISR, so check that a task has + not already been woken. */ + if (!(*pxTaskWoken)) + { + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToSend))) + { + if (xTaskRemoveFromEventList + (&(pxQueue->xTasksWaitingToSend)) != pdFALSE) + { + /* The task waiting has a higher priority than us so + force a context switch. */ + *pxTaskWoken = pdTRUE; + } + } + } + } + else + { + /* Increment the lock count so the task that unlocks the queue + knows that data was removed while it was locked. */ + ++(pxQueue->xRxLock); + } + + xReturn = pdPASS; + } + else + { + xReturn = pdFAIL; + } + + return xReturn; +} + +/*-----------------------------------------------------------*/ + +unsigned portBASE_TYPE +uxQueueMessagesWaiting (xQueueHandle pxQueue) +{ + unsigned portBASE_TYPE uxReturn; + + taskENTER_CRITICAL (); + uxReturn = pxQueue->uxMessagesWaiting; + taskEXIT_CRITICAL (); + + return uxReturn; +} + +/*-----------------------------------------------------------*/ + +void +vQueueDelete (xQueueHandle pxQueue) +{ + vPortFree (pxQueue->pcHead); + vPortFree (pxQueue); +} + +/*-----------------------------------------------------------*/ + +static void +prvUnlockQueue (xQueueHandle pxQueue) +{ + /* THIS FUNCTION MUST BE CALLED WITH THE SCHEDULER SUSPENDED. */ + + /* The lock counts contains the number of extra data items placed or + removed from the queue while the queue was locked. When a queue is + locked items can be added or removed, but the event lists cannot be + updated. */ + taskENTER_CRITICAL (); + { + --(pxQueue->xTxLock); + + /* See if data was added to the queue while it was locked. */ + if (pxQueue->xTxLock > queueUNLOCKED) + { + pxQueue->xTxLock = queueUNLOCKED; + + /* Data was posted while the queue was locked. Are any tasks + blocked waiting for data to become available? */ + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToReceive))) + { + /* Tasks that are removed from the event list will get added to + the pending ready list as the scheduler is still suspended. */ + if (xTaskRemoveFromEventList (&(pxQueue->xTasksWaitingToReceive)) + != pdFALSE) + { + /* The task waiting has a higher priority so record that a + context switch is required. */ + vTaskMissedYield (); + } + } + } + } + taskEXIT_CRITICAL (); + + /* Do the same for the Rx lock. */ + taskENTER_CRITICAL (); + { + --(pxQueue->xRxLock); + + if (pxQueue->xRxLock > queueUNLOCKED) + { + pxQueue->xRxLock = queueUNLOCKED; + + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToSend))) + { + if (xTaskRemoveFromEventList (&(pxQueue->xTasksWaitingToSend)) != + pdFALSE) + { + vTaskMissedYield (); + } + } + } + } + taskEXIT_CRITICAL (); +} + +/*-----------------------------------------------------------*/ + +static signed portBASE_TYPE +prvIsQueueEmpty (const xQueueHandle pxQueue) +{ + signed portBASE_TYPE xReturn; + + taskENTER_CRITICAL (); + xReturn = (pxQueue->uxMessagesWaiting == (unsigned portBASE_TYPE) 0); + taskEXIT_CRITICAL (); + + return xReturn; +} + +/*-----------------------------------------------------------*/ + +static signed portBASE_TYPE +prvIsQueueFull (const xQueueHandle pxQueue) +{ + signed portBASE_TYPE xReturn; + + taskENTER_CRITICAL (); + xReturn = (pxQueue->uxMessagesWaiting == pxQueue->uxLength); + taskEXIT_CRITICAL (); + + return xReturn; +} + +/*-----------------------------------------------------------*/ + +#if configUSE_CO_ROUTINES == 1 +signed portBASE_TYPE +xQueueCRSend (xQueueHandle pxQueue, const void *pvItemToQueue, + portTickType xTicksToWait) +{ + signed portBASE_TYPE xReturn; + + /* If the queue is already full we may have to block. A critical section + is required to prevent an interrupt removing something from the queue + between the check to see if the queue is full and blocking on the queue. */ + portDISABLE_INTERRUPTS (); + { + if (prvIsQueueFull (pxQueue)) + { + /* The queue is full - do we want to block or just leave without + posting? */ + if (xTicksToWait > (portTickType) 0) + { + /* As this is called from a coroutine we cannot block directly, but + return indicating that we need to block. */ + vCoRoutineAddToDelayedList (xTicksToWait, + &(pxQueue->xTasksWaitingToSend)); + portENABLE_INTERRUPTS (); + return errQUEUE_BLOCKED; + } + else + { + portENABLE_INTERRUPTS (); + return errQUEUE_FULL; + } + } + } + portENABLE_INTERRUPTS (); + + portNOP (); + + portDISABLE_INTERRUPTS (); + { + if (pxQueue->uxMessagesWaiting < pxQueue->uxLength) + { + /* There is room in the queue, copy the data into the queue. */ + prvCopyQueueData (pxQueue, pvItemToQueue); + xReturn = pdPASS; + + /* Were any co-routines waiting for data to become available? */ + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToReceive))) + { + /* In this instance the co-routine could be placed directly + into the ready list as we are within a critical section. + Instead the same pending ready list mechansim is used as if + the event were caused from within an interrupt. */ + if (xCoRoutineRemoveFromEventList + (&(pxQueue->xTasksWaitingToReceive)) != pdFALSE) + { + /* The co-routine waiting has a higher priority so record + that a yield might be appropriate. */ + xReturn = errQUEUE_YIELD; + } + } + } + else + { + xReturn = errQUEUE_FULL; + } + } + portENABLE_INTERRUPTS (); + + return xReturn; +} +#endif +/*-----------------------------------------------------------*/ + +#if configUSE_CO_ROUTINES == 1 +signed portBASE_TYPE +xQueueCRReceive (xQueueHandle pxQueue, void *pvBuffer, + portTickType xTicksToWait) +{ + signed portBASE_TYPE xReturn; + + /* If the queue is already empty we may have to block. A critical section + is required to prevent an interrupt adding something to the queue + between the check to see if the queue is empty and blocking on the queue. */ + portDISABLE_INTERRUPTS (); + { + if (pxQueue->uxMessagesWaiting == (unsigned portBASE_TYPE) 0) + { + /* There are no messages in the queue, do we want to block or just + leave with nothing? */ + if (xTicksToWait > (portTickType) 0) + { + /* As this is a co-routine we cannot block directly, but return + indicating that we need to block. */ + vCoRoutineAddToDelayedList (xTicksToWait, + &(pxQueue->xTasksWaitingToReceive)); + portENABLE_INTERRUPTS (); + return errQUEUE_BLOCKED; + } + else + { + portENABLE_INTERRUPTS (); + return errQUEUE_FULL; + } + } + } + portENABLE_INTERRUPTS (); + + portNOP (); + + portDISABLE_INTERRUPTS (); + { + if (pxQueue->uxMessagesWaiting > (unsigned portBASE_TYPE) 0) + { + /* Data is available from the queue. */ + pxQueue->pcReadFrom += pxQueue->uxItemSize; + if (pxQueue->pcReadFrom >= pxQueue->pcTail) + { + pxQueue->pcReadFrom = pxQueue->pcHead; + } + --(pxQueue->uxMessagesWaiting); + memcpy ((void *) pvBuffer, (void *) pxQueue->pcReadFrom, + (unsigned) pxQueue->uxItemSize); + + xReturn = pdPASS; + + /* Were any co-routines waiting for space to become available? */ + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToSend))) + { + /* In this instance the co-routine could be placed directly + into the ready list as we are within a critical section. + Instead the same pending ready list mechansim is used as if + the event were caused from within an interrupt. */ + if (xCoRoutineRemoveFromEventList + (&(pxQueue->xTasksWaitingToSend)) != pdFALSE) + { + xReturn = errQUEUE_YIELD; + } + } + } + else + { + xReturn = pdFAIL; + } + } + portENABLE_INTERRUPTS (); + + return xReturn; +} +#endif +/*-----------------------------------------------------------*/ + + + +#if configUSE_CO_ROUTINES == 1 +signed portBASE_TYPE +xQueueCRSendFromISR (xQueueHandle pxQueue, const void *pvItemToQueue, + signed portBASE_TYPE xCoRoutinePreviouslyWoken) +{ + /* Cannot block within an ISR so if there is no space on the queue then + exit without doing anything. */ + if (pxQueue->uxMessagesWaiting < pxQueue->uxLength) + { + prvCopyQueueData (pxQueue, pvItemToQueue); + + /* We only want to wake one co-routine per ISR, so check that a + co-routine has not already been woken. */ + if (!xCoRoutinePreviouslyWoken) + { + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToReceive))) + { + if (xCoRoutineRemoveFromEventList + (&(pxQueue->xTasksWaitingToReceive)) != pdFALSE) + { + return pdTRUE; + } + } + } + } + + return xCoRoutinePreviouslyWoken; +} +#endif +/*-----------------------------------------------------------*/ + +#if configUSE_CO_ROUTINES == 1 +signed portBASE_TYPE +xQueueCRReceiveFromISR (xQueueHandle pxQueue, void *pvBuffer, + signed portBASE_TYPE * pxCoRoutineWoken) +{ + signed portBASE_TYPE xReturn; + + /* We cannot block from an ISR, so check there is data available. If + not then just leave without doing anything. */ + if (pxQueue->uxMessagesWaiting > (unsigned portBASE_TYPE) 0) + { + /* Copy the data from the queue. */ + pxQueue->pcReadFrom += pxQueue->uxItemSize; + if (pxQueue->pcReadFrom >= pxQueue->pcTail) + { + pxQueue->pcReadFrom = pxQueue->pcHead; + } + --(pxQueue->uxMessagesWaiting); + memcpy ((void *) pvBuffer, (void *) pxQueue->pcReadFrom, + (unsigned) pxQueue->uxItemSize); + + if (!(*pxCoRoutineWoken)) + { + if (!listLIST_IS_EMPTY (&(pxQueue->xTasksWaitingToSend))) + { + if (xCoRoutineRemoveFromEventList + (&(pxQueue->xTasksWaitingToSend)) != pdFALSE) + { + *pxCoRoutineWoken = pdTRUE; + } + } + } + + xReturn = pdPASS; + } + else + { + xReturn = pdFAIL; + } + + return xReturn; +} +#endif +/*-----------------------------------------------------------*/ |