diff options
Diffstat (limited to 'cpukit/score/src/coremsgseize.c')
| -rw-r--r-- | cpukit/score/src/coremsgseize.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/cpukit/score/src/coremsgseize.c b/cpukit/score/src/coremsgseize.c new file mode 100644 index 0000000000..9a9fd75567 --- /dev/null +++ b/cpukit/score/src/coremsgseize.c @@ -0,0 +1,157 @@ +/* + * CORE Message Queue Handler + * + * DESCRIPTION: + * + * This package is the implementation of the CORE Message Queue Handler. + * This core object provides task synchronization and communication functions + * via messages passed to queue objects. + * + * COPYRIGHT (c) 1989-2007. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. + * + * $Id$ + */ + +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include <rtems/system.h> +#include <rtems/score/chain.h> +#include <rtems/score/isr.h> +#include <rtems/score/object.h> +#include <rtems/score/coremsg.h> +#include <rtems/score/states.h> +#include <rtems/score/thread.h> +#include <rtems/score/wkspace.h> + +/*PAGE + * + * _CORE_message_queue_Seize + * + * This kernel routine dequeues a message, copies the message buffer to + * a given destination buffer, and frees the message buffer to the + * inactive message pool. The thread will be blocked if wait is true, + * otherwise an error will be given to the thread if no messages are available. + * + * Input parameters: + * the_message_queue - pointer to message queue + * id - id of object we are waitig on + * buffer - pointer to message buffer to be filled + * size_p - pointer to the size of buffer to be filled + * wait - true if wait is allowed, false otherwise + * timeout - time to wait for a message + * + * Output parameters: NONE + * + * NOTE: Dependent on BUFFER_LENGTH + * + * INTERRUPT LATENCY: + * available + * wait + */ + +void _CORE_message_queue_Seize( + CORE_message_queue_Control *the_message_queue, + Objects_Id id, + void *buffer, + size_t *size_p, + bool wait, + Watchdog_Interval timeout +) +{ + ISR_Level level; + CORE_message_queue_Buffer_control *the_message; + Thread_Control *executing; + + executing = _Thread_Executing; + executing->Wait.return_code = CORE_MESSAGE_QUEUE_STATUS_SUCCESSFUL; + _ISR_Disable( level ); + the_message = _CORE_message_queue_Get_pending_message( the_message_queue ); + if ( the_message != NULL ) { + the_message_queue->number_of_pending_messages -= 1; + _ISR_Enable( level ); + + *size_p = the_message->Contents.size; + _Thread_Executing->Wait.count = + _CORE_message_queue_Get_message_priority( the_message ); + _CORE_message_queue_Copy_buffer( + the_message->Contents.buffer, + buffer, + *size_p + ); + + #if !defined(RTEMS_SCORE_COREMSG_ENABLE_BLOCKING_SEND) + /* + * There is not an API with blocking sends enabled. + * So return immediately. + */ + _CORE_message_queue_Free_message_buffer(the_message_queue, the_message); + return; + #else + { + Thread_Control *the_thread; + + /* + * There could be a thread waiting to send a message. If there + * is not, then we can go ahead and free the buffer. + * + * NOTE: If we note that the queue was not full before this receive, + * then we can avoid this dequeue. + */ + the_thread = _Thread_queue_Dequeue( &the_message_queue->Wait_queue ); + if ( !the_thread ) { + _CORE_message_queue_Free_message_buffer( + the_message_queue, + the_message + ); + return; + } + + /* + * There was a thread waiting to send a message. This code + * puts the messages in the message queue on behalf of the + * waiting task. + */ + _CORE_message_queue_Set_message_priority( + the_message, + the_thread->Wait.count + ); + the_message->Contents.size = (size_t) the_thread->Wait.option; + _CORE_message_queue_Copy_buffer( + the_thread->Wait.return_argument_second.immutable_object, + the_message->Contents.buffer, + the_message->Contents.size + ); + + _CORE_message_queue_Insert_message( + the_message_queue, + the_message, + _CORE_message_queue_Get_message_priority( the_message ) + ); + return; + } + #endif + } + + if ( !wait ) { + _ISR_Enable( level ); + executing->Wait.return_code = CORE_MESSAGE_QUEUE_STATUS_UNSATISFIED_NOWAIT; + return; + } + + _Thread_queue_Enter_critical_section( &the_message_queue->Wait_queue ); + executing->Wait.queue = &the_message_queue->Wait_queue; + executing->Wait.id = id; + executing->Wait.return_argument_second.mutable_object = buffer; + executing->Wait.return_argument = size_p; + /* Wait.count will be filled in with the message priority */ + _ISR_Enable( level ); + + _Thread_queue_Enqueue( &the_message_queue->Wait_queue, timeout ); +} |