/**
* @file
*
* @brief Inlined Routines Associated with the SuperCore Semaphore
*
* This include file contains all of the inlined routines associated
* with the SuperCore semaphore.
*/
/*
* COPYRIGHT (c) 1989-2006.
* 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.org/license/LICENSE.
*/
#ifndef _RTEMS_SCORE_CORESEMIMPL_H
#define _RTEMS_SCORE_CORESEMIMPL_H
#include <rtems/score/coresem.h>
#include <rtems/score/objectimpl.h>
#include <rtems/score/threaddispatch.h>
#include <rtems/score/threadqimpl.h>
#include <rtems/score/statesimpl.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @addtogroup ScoreSemaphore
*/
/**@{**/
/**
* Core Semaphore handler return statuses.
*/
typedef enum {
/** This status indicates that the operation completed successfully. */
CORE_SEMAPHORE_STATUS_SUCCESSFUL,
/** This status indicates that the calling task did not want to block
* and the operation was unable to complete immediately because the
* resource was unavailable.
*/
CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT,
/** This status indicates that the thread was blocked waiting for an
* operation to complete and the semaphore was deleted.
*/
CORE_SEMAPHORE_WAS_DELETED,
/** This status indicates that the calling task was willing to block
* but the operation was unable to complete within the time allotted
* because the resource never became available.
*/
CORE_SEMAPHORE_TIMEOUT,
/** This status indicates that an attempt was made to unlock the semaphore
* and this would have made its count greater than that allowed.
*/
CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED
} CORE_semaphore_Status;
/**
* @brief Core semaphore last status value.
*
* This is the last status value.
*/
#define CORE_SEMAPHORE_STATUS_LAST CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED
/**
* @brief Initialize the semaphore based on the parameters passed.
*
* This package is the implementation of the CORE Semaphore Handler.
* This core object utilizes standard Dijkstra counting semaphores to provide
* synchronization and mutual exclusion capabilities.
*
* This routine initializes the semaphore based on the parameters passed.
*
* @param[in] the_semaphore is the semaphore to initialize
* @param[in] discipline the blocking discipline
* @param[in] initial_value is the initial count of the semaphore
*/
void _CORE_semaphore_Initialize(
CORE_semaphore_Control *the_semaphore,
CORE_semaphore_Disciplines discipline,
uint32_t initial_value
);
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Acquire_critical(
CORE_semaphore_Control *the_semaphore,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Acquire_critical(
&the_semaphore->Wait_queue,
&queue_context->Lock_context
);
}
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Release(
CORE_semaphore_Control *the_semaphore,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Release(
&the_semaphore->Wait_queue,
&queue_context->Lock_context
);
}
Thread_Control *_CORE_semaphore_Was_deleted(
Thread_Control *the_thread,
Thread_queue_Queue *queue,
Thread_queue_Context *queue_context
);
Thread_Control *_CORE_semaphore_Unsatisfied_nowait(
Thread_Control *the_thread,
Thread_queue_Queue *queue,
Thread_queue_Context *queue_context
);
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy(
CORE_semaphore_Control *the_semaphore,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Flush_critical(
&the_semaphore->Wait_queue.Queue,
the_semaphore->operations,
_CORE_semaphore_Was_deleted,
queue_context
);
_Thread_queue_Destroy( &the_semaphore->Wait_queue );
}
/**
* @brief Surrender a unit to a semaphore.
*
* This routine frees a unit to the semaphore. If a task was blocked waiting
* for a unit from this semaphore, then that task will be readied and the unit
* given to that task. Otherwise, the unit will be returned to the semaphore.
*
* @param[in] the_semaphore is the semaphore to surrender
* @param[in] queue_context is a temporary variable used to contain the ISR
* disable level cookie
*
* @retval an indication of whether the routine succeeded or failed
*/
RTEMS_INLINE_ROUTINE CORE_semaphore_Status _CORE_semaphore_Surrender(
CORE_semaphore_Control *the_semaphore,
uint32_t maximum_count,
Thread_queue_Context *queue_context
)
{
Thread_Control *the_thread;
CORE_semaphore_Status status;
status = CORE_SEMAPHORE_STATUS_SUCCESSFUL;
_CORE_semaphore_Acquire_critical( the_semaphore, queue_context );
the_thread = _Thread_queue_First_locked(
&the_semaphore->Wait_queue,
the_semaphore->operations
);
if ( the_thread != NULL ) {
_Thread_queue_Extract_critical(
&the_semaphore->Wait_queue.Queue,
the_semaphore->operations,
the_thread,
queue_context
);
} else {
if ( the_semaphore->count < maximum_count )
the_semaphore->count += 1;
else
status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED;
_CORE_semaphore_Release( the_semaphore, queue_context );
}
return status;
}
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Flush(
CORE_semaphore_Control *the_semaphore,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Flush_critical(
&the_semaphore->Wait_queue.Queue,
the_semaphore->operations,
_CORE_semaphore_Unsatisfied_nowait,
queue_context
);
}
/**
* This routine returns the current count associated with the semaphore.
*
* @param[in] the_semaphore is the semaphore to obtain the count of
*
* @return the current count of this semaphore
*/
RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count(
CORE_semaphore_Control *the_semaphore
)
{
return the_semaphore->count;
}
/**
* This routine attempts to receive a unit from the_semaphore.
* If a unit is available or if the wait flag is false, then the routine
* returns. Otherwise, the calling task is blocked until a unit becomes
* available.
*
* @param[in] the_semaphore is the semaphore to obtain
* @param[in,out] executing The currently executing thread.
* @param[in] wait is true if the thread is willing to wait
* @param[in] timeout is the maximum number of ticks to block
* @param[in] queue_context is a temporary variable used to contain the ISR
* disable level cookie
*
* @note There is currently no MACRO version of this routine.
*/
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Seize(
CORE_semaphore_Control *the_semaphore,
Thread_Control *executing,
bool wait,
Watchdog_Interval timeout,
Thread_queue_Context *queue_context
)
{
/* disabled when you get here */
executing->Wait.return_code = CORE_SEMAPHORE_STATUS_SUCCESSFUL;
_CORE_semaphore_Acquire_critical( the_semaphore, queue_context );
if ( the_semaphore->count != 0 ) {
the_semaphore->count -= 1;
_CORE_semaphore_Release( the_semaphore, queue_context );
return;
}
if ( !wait ) {
_CORE_semaphore_Release( the_semaphore, queue_context );
executing->Wait.return_code = CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT;
return;
}
_Thread_queue_Enqueue_critical(
&the_semaphore->Wait_queue.Queue,
the_semaphore->operations,
executing,
STATES_WAITING_FOR_SEMAPHORE,
timeout,
CORE_SEMAPHORE_TIMEOUT,
&queue_context->Lock_context
);
}
/** @} */
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
