/**
* @file
*
* @ingroup RTEMSScoreSemaphore
*
* @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/threadimpl.h>
#include <rtems/score/threadqimpl.h>
#include <rtems/score/statesimpl.h>
#include <rtems/score/status.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @addtogroup RTEMSScoreSemaphore
*
* @{
*/
/**
* @brief Initializes 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[out] the_semaphore The semaphore to initialize.
* @param initial_value The initial count of the semaphore.
*/
void _CORE_semaphore_Initialize(
CORE_semaphore_Control *the_semaphore,
uint32_t initial_value
);
/**
* @brief Acquires the semaphore critical.
*
* This routine acquires the semaphore.
*
* @param[in, out] the_semaphore The semaphore to acquire.
* @param queue_context The thread queue context.
*/
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 );
}
/**
* @brief Releases the semaphore.
*
* This routine releases the semaphore.
*
* @param[in, out] the_semaphore The semaphore to release.
* @param queue_context The thread queue 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 );
}
/**
* @brief Destroys the semaphore.
*
* This routine destroys the semaphore.
*
* @param[out] the_semaphore The semaphore to destroy.
* @param operations The thread queue operations.
* @param queue_context The thread queue context.
*/
RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy(
CORE_semaphore_Control *the_semaphore,
const Thread_queue_Operations *operations,
Thread_queue_Context *queue_context
)
{
_Thread_queue_Flush_critical(
&the_semaphore->Wait_queue.Queue,
operations,
_Thread_queue_Flush_status_object_was_deleted,
queue_context
);
_Thread_queue_Destroy( &the_semaphore->Wait_queue );
}
/**
* @brief Surrenders a unit to the 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, out] the_semaphore is the semaphore to surrender
* @param operations The thread queue operations.
* @param maximum_count The maximum number of units in the semaphore.
* @param queue_context is a temporary variable used to contain the ISR
* disable level cookie.
*
* @retval STATUS_SUCCESSFUL The unit was successfully freed to the semaphore.
* @retval STATUS_MAXIMUM_COUNT_EXCEEDED The maximum number of units was exceeded.
*/
RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Surrender(
CORE_semaphore_Control *the_semaphore,
const Thread_queue_Operations *operations,
uint32_t maximum_count,
Thread_queue_Context *queue_context
)
{
Thread_Control *the_thread;
Status_Control status;
status = STATUS_SUCCESSFUL;
_CORE_semaphore_Acquire_critical( the_semaphore, queue_context );
the_thread = _Thread_queue_First_locked(
&the_semaphore->Wait_queue,
operations
);
if ( the_thread != NULL ) {
_Thread_queue_Extract_critical(
&the_semaphore->Wait_queue.Queue,
operations,
the_thread,
queue_context
);
} else {
if ( the_semaphore->count < maximum_count )
the_semaphore->count += 1;
else
status = STATUS_MAXIMUM_COUNT_EXCEEDED;
_CORE_semaphore_Release( the_semaphore, queue_context );
}
return status;
}
/**
* @brief Returns the current count associated with the semaphore.
*
* @param the_semaphore The semaphore to obtain the count of.
*
* @return the current count of this semaphore.
*/
RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count(
const CORE_semaphore_Control *the_semaphore
)
{
return the_semaphore->count;
}
/**
* @brief Seizes the semaphore
*
* 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, out] the_semaphore The semaphore to obtain.
* @param operations The thread queue operations.
* @param executing The currently executing thread.
* @param wait Indicates whether the calling thread is willing to wait.
* @param queue_context is a temporary variable used to contain the ISR
* disable level cookie.
*
* @retval STATUS_SUCCESSFUL The semaphore was successfully seized.
* @retval STATUS_UNSATISFIED The semaphore is currently not free and the
* calling thread not willing to wait.
* @retval STATUS_TIMEOUT A timeout occured.
*/
RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Seize(
CORE_semaphore_Control *the_semaphore,
const Thread_queue_Operations *operations,
Thread_Control *executing,
bool wait,
Thread_queue_Context *queue_context
)
{
_Assert( _ISR_Get_level() != 0 );
_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 STATUS_SUCCESSFUL;
}
if ( !wait ) {
_CORE_semaphore_Release( the_semaphore, queue_context );
return STATUS_UNSATISFIED;
}
_Thread_queue_Context_set_thread_state(
queue_context,
STATES_WAITING_FOR_SEMAPHORE
);
_Thread_queue_Enqueue(
&the_semaphore->Wait_queue.Queue,
operations,
executing,
queue_context
);
return _Thread_Wait_get_status( executing );
}
/** @} */
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
