/** * @file coremsg.h * * This include file contains all the constants and structures associated * with the Message queue Handler. */ /* * COPYRIGHT (c) 1989-2004. * 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. * * $Id$ */ #ifndef __RTEMS_CORE_MESSAGE_QUEUE_h #define __RTEMS_CORE_MESSAGE_QUEUE_h /** * @defgroup ScoreMessageQueue Message Queue Handler * * This group contains functionality which provides the foundation * Message Queue services used in all of the APIs supported by RTEMS. */ /**@{*/ #ifdef __cplusplus extern "C" { #endif #include #include #include #include #include /** * The following type defines the callout which the API provides * to support global/multiprocessor operations on message_queues. */ typedef void ( *CORE_message_queue_API_mp_support_callout )( Thread_Control *, Objects_Id ); /** * The following defines the data types needed to manipulate * the contents of message buffers. * * @note The buffer field is normally longer than a single uint32_t * but since messages are variable length we just make a ptr to 1. */ typedef struct { /** This field is the size of this message. */ uint32_t size; /** This field contains the actual message. */ uint32_t buffer[1]; } CORE_message_queue_Buffer; /** * The following records define the organization of a message * buffer. */ typedef struct { /** This element allows this structure to be placed on chains. */ Chain_Node Node; /** This field is the priority of this message. */ int priority; /** This field points to the contents of the message. */ CORE_message_queue_Buffer Contents; } CORE_message_queue_Buffer_control; /** * Blocking disciplines for a message queue. */ typedef enum { /** This value indicates that pending messages are in FIFO order. */ CORE_MESSAGE_QUEUE_DISCIPLINES_FIFO, /** This value indicates that pending messages are in priority order. */ CORE_MESSAGE_QUEUE_DISCIPLINES_PRIORITY } CORE_message_queue_Disciplines; /** * This is the priority constant used when appending messages onto * a message queue. */ #define CORE_MESSAGE_QUEUE_SEND_REQUEST INT_MAX /** * This is the priority constant used when prepending messages onto * a message queue. */ #define CORE_MESSAGE_QUEUE_URGENT_REQUEST INT_MIN /** * The following enumerated type details the modes in which a message * may be submitted to a message queue. The message may be posted * in a send or urgent fashion. * * @note All other values are message priorities. Numerically smaller * priorities indicate higher priority messages. */ typedef int CORE_message_queue_Submit_types; /** * Core Message queue handler return statuses. */ typedef enum { /** This value indicates the operation completed sucessfully. */ CORE_MESSAGE_QUEUE_STATUS_SUCCESSFUL, /** This value indicates that the message was too large for this queue. */ CORE_MESSAGE_QUEUE_STATUS_INVALID_SIZE, /** This value indicates that there are too many messages pending. */ CORE_MESSAGE_QUEUE_STATUS_TOO_MANY, /** This value indicates that a receive was unsuccessful. */ CORE_MESSAGE_QUEUE_STATUS_UNSATISFIED, /** This value indicates that a blocking send was unsuccessful. */ CORE_MESSAGE_QUEUE_STATUS_UNSATISFIED_NOWAIT, /** This value indicates that the message queue being blocked upon * was deleted while the thread was waiting. */ CORE_MESSAGE_QUEUE_STATUS_WAS_DELETED, /** This value indicates that the thread had to timeout while waiting * to receive a message because one did not become available. */ CORE_MESSAGE_QUEUE_STATUS_TIMEOUT, /** This value indicates that a blocking receive was unsuccessful. */ CORE_MESSAGE_QUEUE_STATUS_UNSATISFIED_WAIT } CORE_message_queue_Status; /** * The following defines the control block used to manage the * attributes of each message queue. */ typedef struct { /** This field specifies the order in which blocking tasks will be ordered. */ CORE_message_queue_Disciplines discipline; } CORE_message_queue_Attributes; /** * The following defines the type for a Notification handler. A notification * handler is invoked when the message queue makes a 0->1 transition on * pending messages. */ typedef void (*CORE_message_queue_Notify_Handler)( void * ); /** * The following defines the control block used to manage each * counting message_queue. */ typedef struct { /** This field is the Waiting Queue used to manage the set of tasks * which are blocked waiting to receive a message from this queue. */ Thread_queue_Control Wait_queue; /** This element is the set of attributes which define this instance's * behavior. */ CORE_message_queue_Attributes Attributes; /** This element is maximum number of messages which may be pending * at any given time. */ uint32_t maximum_pending_messages; /** This element is the number of messages which are currently pending. */ uint32_t number_of_pending_messages; /** This is the size in bytes of the largest message which may be * sent via this queue. */ uint32_t maximum_message_size; /** This chain is the set of pending messages. It may be ordered by * message priority or in FIFO order. */ Chain_Control Pending_messages; /** This is the address of the memory allocated for message buffers. * It is allocated are part of message queue initialization and freed * as part of destroying it. */ CORE_message_queue_Buffer *message_buffers; /** This is the routine invoked when the message queue transitions * from zero (0) messages pending to one (1) message pending. */ CORE_message_queue_Notify_Handler notify_handler; /** This field is the argument passed to the @ref notify_argument. */ void *notify_argument; /** This chain is the set of inactive messages. A message is inactive * when it does not contain a pending message. */ Chain_Control Inactive_messages; } CORE_message_queue_Control; /** * This routine initializes the message_queue based on the parameters passed. * * @param the_message_queue (in) points to the message queue to initialize * @param the_message_queue_attributes (in) points to the attributes that * will be used with this message queue instance * @param maximum_pending_messages (in) is the maximum number of messages * that will be allowed to pend at any given time * @param maximum_message_size (in) is the size of largest message that * may be sent to this message queue instance * * @return TRUE if the message queue can be initialized. In general, * FALSE will only be returned if memory for the pending * messages cannot be allocated. */ boolean _CORE_message_queue_Initialize( CORE_message_queue_Control *the_message_queue, CORE_message_queue_Attributes *the_message_queue_attributes, uint32_t maximum_pending_messages, uint32_t maximum_message_size ); /** * This function closes a message by returning all allocated space and * flushing the message_queue's task wait queue. * * @param the_message_queue (in) points to the message queue to close * @param remote_extract_callout (in) is the routine to call for each thread * that is extracted from the set of waiting threads * @param status (in) is the status that each waiting thread will return * from it's blocking service */ void _CORE_message_queue_Close( CORE_message_queue_Control *the_message_queue, Thread_queue_Flush_callout remote_extract_callout, uint32_t status ); /** * This function flushes the message_queue's pending message queue. The * number of messages flushed from the queue is returned. * * @param the_message_queue (in) points to the message queue to flush * @return the number of message pending messages flushed */ uint32_t _CORE_message_queue_Flush( CORE_message_queue_Control *the_message_queue ); /** * This routine flushes all outstanding messages and returns * them to the inactive message chain. * * @param the_message_queue (in) points to the message queue to flush * @return the number of message pending messages flushed */ uint32_t _CORE_message_queue_Flush_support( CORE_message_queue_Control *the_message_queue ); /** * This function flushes the threads which are blocked on this * message_queue's pending message queue. They are unblocked whether * blocked sending or receiving. * * @param the_message_queue (in) points to the message queue to flush */ void _CORE_message_queue_Flush_waiting_threads( CORE_message_queue_Control *the_message_queue ); /** * This function sends a message for every thread waiting on the queue and * returns the number of threads made ready by the message. * * @param the_message_queue (in) points to the message queue * @param buffer (in) is the starting address of the message to broadcast * @param size (in) is the size of the message being broadcast * @param id (in) is the RTEMS object Id associated with this message queue. * It is used when unblocking a remote thread. * @param api_message_queue_mp_support (in) is the routine to invoke if * a thread that is unblocked is actually a remote thread. * @param count (out) points to the variable that will contain the * number of tasks that are sent this message * @return @a *count will contain the number of messages sent * @return indication of the successful completion or reason for failure */ CORE_message_queue_Status _CORE_message_queue_Broadcast( CORE_message_queue_Control *the_message_queue, void *buffer, uint32_t size, Objects_Id id, CORE_message_queue_API_mp_support_callout api_message_queue_mp_support, uint32_t *count ); /** * This routine implements the send and urgent message functions. It * processes a message that is to be submitted to the designated * message queue. The message will either be processed as a * send message which it will be inserted at the rear of the queue * or it will be processed as an urgent message which will be inserted * at the front of the queue. * * @param the_message_queue (in) points to the message queue * @param buffer (in) is the starting address of the message to send * @param size (in) is the size of the message being send * @param id (in) is the RTEMS object Id associated with this message queue. * It is used when unblocking a remote thread. * @param api_message_queue_mp_support (in) is the routine to invoke if * a thread that is unblocked is actually a remote thread. * @param submit_type (in) determines whether the message is prepended, * appended, or enqueued in priority order. * @param wait (in) indicates whether the calling thread is willing to block * if the message queue is full. * @param timeout (in) is the maximum number of clock ticks that the calling * thread is willing to block if the message queue is full. * @return indication of the successful completion or reason for failure */ CORE_message_queue_Status _CORE_message_queue_Submit( CORE_message_queue_Control *the_message_queue, void *buffer, uint32_t size, Objects_Id id, CORE_message_queue_API_mp_support_callout api_message_queue_mp_support, CORE_message_queue_Submit_types submit_type, boolean wait, Watchdog_Interval timeout ); /** * 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. * * @param the_message_queue (in) points to the message queue * @param id (in) is the RTEMS object Id associated with this message queue. * It is used when unblocking a remote thread. * @param buffer (in) is the starting address of the message buffer to * to be filled in with a message * @param size (in) is the size of the @a buffer and indicates the maximum * size message that the caller can receive. * @param wait (in) indicates whether the calling thread is willing to block * if the message queue is empty. * @param timeout (in) is the maximum number of clock ticks that the calling * thread is willing to block if the message queue is empty. * * @return indication of the successful completion or reason for failure * @note Returns message priority via return are in TCB. */ void _CORE_message_queue_Seize( CORE_message_queue_Control *the_message_queue, Objects_Id id, void *buffer, uint32_t *size, boolean wait, Watchdog_Interval timeout ); /** * This kernel routine inserts the specified message into the * message queue. It is assumed that the message has been filled * in before this routine is called. * * @param the_message_queue (in) points to the message queue * @param the_message (in) is the message to enqueue * @param submit_type (in) determines whether the message is prepended, * appended, or enqueued in priority order. */ void _CORE_message_queue_Insert_message( CORE_message_queue_Control *the_message_queue, CORE_message_queue_Buffer_control *the_message, CORE_message_queue_Submit_types submit_type ); #ifndef __RTEMS_APPLICATION__ #include #endif #ifdef __cplusplus } #endif /**@}*/ #endif /* end of include file */