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Diffstat (limited to 'openpicc/os/core/include/queue.h')
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diff --git a/openpicc/os/core/include/queue.h b/openpicc/os/core/include/queue.h new file mode 100644 index 0000000..e95d7b0 --- /dev/null +++ b/openpicc/os/core/include/queue.h @@ -0,0 +1,492 @@ +/* + 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. + *************************************************************************** +*/ + +#ifndef QUEUE_H +#define QUEUE_H + +typedef void *xQueueHandle; + +/** + * queue. h + * <pre> + xQueueHandle xQueueCreate( + unsigned portBASE_TYPE uxQueueLength, + unsigned portBASE_TYPE uxItemSize + ); + * </pre> + * + * Creates a new queue instance. This allocates the storage required by the + * new queue and returns a handle for the queue. + * + * @param uxQueueLength The maximum number of items that the queue can contain. + * + * @param uxItemSize The number of bytes each item in the queue will require. + * Items are queued by copy, not by reference, so this is the number of bytes + * that will be copied for each posted item. Each item on the queue must be + * the same size. + * + * @return If the queue is successfully create then a handle to the newly + * created queue is returned. If the queue cannot be created then 0 is + * returned. + * + * Example usage: + <pre> + struct AMessage + { + portCHAR ucMessageID; + portCHAR ucData[ 20 ]; + }; + + void vATask( void *pvParameters ) + { + xQueueHandle xQueue1, xQueue2; + + // Create a queue capable of containing 10 unsigned long values. + xQueue1 = xQueueCreate( 10, sizeof( unsigned portLONG ) ); + if( xQueue1 == 0 ) + { + // Queue was not created and must not be used. + } + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + if( xQueue2 == 0 ) + { + // Queue was not created and must not be used. + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueCreate xQueueCreate + * \ingroup QueueManagement + */ +xQueueHandle xQueueCreate (unsigned portBASE_TYPE uxQueueLength, + unsigned portBASE_TYPE uxItemSize); + +/** + * queue. h + * <pre> + portBASE_TYPE xQueueSend( + xQueueHandle xQueue, + const void * pvItemToQueue, + portTickType xTicksToWait + ); + * </pre> + * + * Post an item on a queue. The item is queued by copy, not by reference. + * This function must not be called from an interrupt service routine. + * See xQueueSendFromISR () for an alternative which may be used in an ISR. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for space to become available on the queue, should it already + * be full. The call will return immediately if this is set to 0. The + * time is defined in tick periods so the constant portTICK_RATE_MS + * should be used to convert to real time if this is required. + * + * @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL. + * + * Example usage: + <pre> + struct AMessage + { + portCHAR ucMessageID; + portCHAR ucData[ 20 ]; + } xMessage; + + unsigned portLONG ulVar = 10UL; + + void vATask( void *pvParameters ) + { + xQueueHandle xQueue1, xQueue2; + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 unsigned long values. + xQueue1 = xQueueCreate( 10, sizeof( unsigned portLONG ) ); + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) ); + + // ... + + if( xQueue1 != 0 ) + { + // Send an unsigned long. Wait for 10 ticks for space to become + // available if necessary. + if( xQueueSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS ) + { + // Failed to post the message, even after 10 ticks. + } + } + + if( xQueue2 != 0 ) + { + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 ); + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueSend xQueueSend + * \ingroup QueueManagement + */ +signed portBASE_TYPE xQueueSend (xQueueHandle xQueue, + const void *pvItemToQueue, + portTickType xTicksToWait); + +/** + * queue. h + * <pre> + portBASE_TYPE xQueueReceive( + xQueueHandle xQueue, + void *pvBuffer, + portTickType xTicksToWait + );</pre> + * + * Receive an item from a queue. The item is received by copy so a buffer of + * adequate size must be provided. The number of bytes copied into the buffer + * was defined when the queue was created. + * + * This function must not be used in an interrupt service routine. See + * xQueueReceiveFromISR for an alternative that can. + * + * @param pxQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @param xTicksToWait The maximum amount of time the task should block + * waiting for an item to receive should the queue be empty at the time + * of the call. The time is defined in tick periods so the constant + * portTICK_RATE_MS should be used to convert to real time if this is required. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * Example usage: + <pre> + struct AMessage + { + portCHAR ucMessageID; + portCHAR ucData[ 20 ]; + } xMessage; + + xQueueHandle xQueue; + + // Task to create a queue and post a value. + void vATask( void *pvParameters ) + { + struct AMessage *pxMessage; + + // Create a queue capable of containing 10 pointers to AMessage structures. + // These should be passed by pointer as they contain a lot of data. + xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) ); + if( xQueue == 0 ) + { + // Failed to create the queue. + } + + // ... + + // Send a pointer to a struct AMessage object. Don't block if the + // queue is already full. + pxMessage = & xMessage; + xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 ); + + // ... Rest of task code. + } + + // Task to receive from the queue. + void vADifferentTask( void *pvParameters ) + { + struct AMessage *pxRxedMessage; + + if( xQueue != 0 ) + { + // Receive a message on the created queue. Block for 10 ticks if a + // message is not immediately available. + if( xQueueReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) ) + { + // pcRxedMessage now points to the struct AMessage variable posted + // by vATask. + } + } + + // ... Rest of task code. + } + </pre> + * \defgroup xQueueReceive xQueueReceive + * \ingroup QueueManagement + */ +signed portBASE_TYPE xQueueReceive (xQueueHandle xQueue, void *pvBuffer, + portTickType xTicksToWait); + +/** + * queue. h + * <pre>unsigned portBASE_TYPE uxQueueMessagesWaiting( xQueueHandle xQueue );</pre> + * + * Return the number of messages stored in a queue. + * + * @param xQueue A handle to the queue being queried. + * + * @return The number of messages available in the queue. + * + * \page uxQueueMessagesWaiting uxQueueMessagesWaiting + * \ingroup QueueManagement + */ +unsigned portBASE_TYPE uxQueueMessagesWaiting (xQueueHandle xQueue); + +/** + * queue. h + * <pre>void vQueueDelete( xQueueHandle xQueue );</pre> + * + * Delete a queue - freeing all the memory allocated for storing of items + * placed on the queue. + * + * @param xQueue A handle to the queue to be deleted. + * + * \page vQueueDelete vQueueDelete + * \ingroup QueueManagement + */ +void vQueueDelete (xQueueHandle xQueue); + +/** + * queue. h + * <pre> + portBASE_TYPE xQueueSendFromISR( + xQueueHandle pxQueue, + const void *pvItemToQueue, + portBASE_TYPE xTaskPreviouslyWoken + ); + </pre> + * + * Post an item on a queue. It is safe to use this function from within an + * interrupt service routine. + * + * Items are queued by copy not reference so it is preferable to only + * queue small items, especially when called from an ISR. In most cases + * it would be preferable to store a pointer to the item being queued. + * + * @param xQueue The handle to the queue on which the item is to be posted. + * + * @param pvItemToQueue A pointer to the item that is to be placed on the + * queue. The size of the items the queue will hold was defined when the + * queue was created, so this many bytes will be copied from pvItemToQueue + * into the queue storage area. + * + * @param cTaskPreviouslyWoken This is included so an ISR can post onto + * the same queue multiple times from a single interrupt. The first call + * should always pass in pdFALSE. Subsequent calls should pass in + * the value returned from the previous call. See the file serial .c in the + * PC port for a good example of this mechanism. + * + * @return pdTRUE if a task was woken by posting onto the queue. This is + * used by the ISR to determine if a context switch may be required following + * the ISR. + * + * Example usage for buffered IO (where the ISR can obtain more than one value + * per call): + <pre> + void vBufferISR( void ) + { + portCHAR cIn; + portBASE_TYPE xTaskWokenByPost; + + // We have not woken a task at the start of the ISR. + cTaskWokenByPost = pdFALSE; + + // Loop until the buffer is empty. + do + { + // Obtain a byte from the buffer. + cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS ); + + // Post the byte. The first time round the loop cTaskWokenByPost + // will be pdFALSE. If the queue send causes a task to wake we do + // not want the task to run until we have finished the ISR, so + // xQueueSendFromISR does not cause a context switch. Also we + // don't want subsequent posts to wake any other tasks, so we store + // the return value back into cTaskWokenByPost so xQueueSendFromISR + // knows not to wake any task the next iteration of the loop. + xTaskWokenByPost = xQueueSendFromISR( xRxQueue, &cIn, cTaskWokenByPost ); + + } while( portINPUT_BYTE( BUFFER_COUNT ) ); + + // Now the buffer is empty we can switch context if necessary. + if( cTaskWokenByPost ) + { + taskYIELD (); + } + } + </pre> + * + * \defgroup xQueueSendFromISR xQueueSendFromISR + * \ingroup QueueManagement + */ +signed portBASE_TYPE xQueueSendFromISR (xQueueHandle pxQueue, + const void *pvItemToQueue, + signed portBASE_TYPE + xTaskPreviouslyWoken); + +/** + * queue. h + * <pre> + portBASE_TYPE xQueueReceiveFromISR( + xQueueHandle pxQueue, + void *pvBuffer, + portBASE_TYPE *pxTaskWoken + ); + * </pre> + * + * Receive an item from a queue. It is safe to use this function from within an + * interrupt service routine. + * + * @param pxQueue The handle to the queue from which the item is to be + * received. + * + * @param pvBuffer Pointer to the buffer into which the received item will + * be copied. + * + * @param pxTaskWoken A task may be blocked waiting for space to become + * available on the queue. If xQueueReceiveFromISR causes such a task to + * unblock *pxTaskWoken will get set to pdTRUE, otherwise *pxTaskWoken will + * remain unchanged. + * + * @return pdTRUE if an item was successfully received from the queue, + * otherwise pdFALSE. + * + * Example usage: + <pre> + + xQueueHandle xQueue; + + // Function to create a queue and post some values. + void vAFunction( void *pvParameters ) + { + portCHAR cValueToPost; + const portTickType xBlockTime = ( portTickType )0xff; + + // Create a queue capable of containing 10 characters. + xQueue = xQueueCreate( 10, sizeof( portCHAR ) ); + if( xQueue == 0 ) + { + // Failed to create the queue. + } + + // ... + + // Post some characters that will be used within an ISR. If the queue + // is full then this task will block for xBlockTime ticks. + cValueToPost = 'a'; + xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime ); + cValueToPost = 'b'; + xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime ); + + // ... keep posting characters ... this task may block when the queue + // becomes full. + + cValueToPost = 'c'; + xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime ); + } + + // ISR that outputs all the characters received on the queue. + void vISR_Routine( void ) + { + portBASE_TYPE xTaskWokenByReceive = pdFALSE; + portCHAR cRxedChar; + + while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) ) + { + // A character was received. Output the character now. + vOutputCharacter( cRxedChar ); + + // If removing the character from the queue woke the task that was + // posting onto the queue cTaskWokenByReceive will have been set to + // pdTRUE. No matter how many times this loop iterates only one + // task will be woken. + } + + if( cTaskWokenByPost != ( portCHAR ) pdFALSE; + { + taskYIELD (); + } + } + </pre> + * \defgroup xQueueReceiveFromISR xQueueReceiveFromISR + * \ingroup QueueManagement + */ +signed portBASE_TYPE xQueueReceiveFromISR (xQueueHandle pxQueue, + void *pvBuffer, + signed portBASE_TYPE * + pxTaskWoken); + + +/* + * The functions defined above are for passing data to and from tasks. The + * functions below are the equivalents for passing data to and from + * co-rtoutines. + * + * These functions are called from the co-routine macro implementation and + * should not be called directly from application code. Instead use the macro + * wrappers defined within croutine.h. + */ +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 |