/**
* @file
*
* @brief Thread Queue Operations
* @ingroup ScoreThreadQ
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/threadqimpl.h>
#include <rtems/score/assert.h>
#include <rtems/score/rbtreeimpl.h>
#include <rtems/score/threadimpl.h>
#include <rtems/score/watchdogimpl.h>
ISR_LOCK_DEFINE( static, _Thread_queue_Lock, "Thread Queue" )
static void _Thread_queue_Acquire( ISR_lock_Context *lock_context )
{
_ISR_lock_ISR_disable_and_acquire( &_Thread_queue_Lock, lock_context );
}
static void _Thread_queue_Release( ISR_lock_Context *lock_context )
{
_ISR_lock_Release_and_ISR_enable( &_Thread_queue_Lock, lock_context );
}
/**
* @brief Finalize a blocking operation.
*
* This method is used to finalize a blocking operation that was
* satisfied. It may be used with thread queues or any other synchronization
* object that uses the blocking states and watchdog times for timeout.
*
* This method will restore the previous ISR disable level during the cancel
* operation. Thus it is an implicit _ISR_Enable().
*
* @param[in] the_thread is the thread whose blocking is canceled
* @param[in] lock_context is the previous ISR disable level
*/
static void _Thread_blocking_operation_Finalize(
Thread_Control *the_thread,
ISR_lock_Context *lock_context
)
{
/*
* The thread is not waiting on anything after this completes.
*/
the_thread->Wait.queue = NULL;
/*
* If the sync state is timed out, this is very likely not needed.
* But better safe than sorry when it comes to critical sections.
*/
if ( _Watchdog_Is_active( &the_thread->Timer ) ) {
_Watchdog_Deactivate( &the_thread->Timer );
_Thread_queue_Release( lock_context );
(void) _Watchdog_Remove( &the_thread->Timer );
} else
_Thread_queue_Release( lock_context );
/*
* Global objects with thread queue's should not be operated on from an
* ISR. But the sync code still must allow short timeouts to be processed
* correctly.
*/
_Thread_Unblock( the_thread );
#if defined(RTEMS_MULTIPROCESSING)
if ( !_Objects_Is_local_id( the_thread->Object.id ) )
_Thread_MP_Free_proxy( the_thread );
#endif
}
static void _Thread_queue_Requeue_priority(
Thread_Control *the_thread,
Priority_Control new_priority,
void *context
)
{
Thread_queue_Control *tq = context;
_RBTree_Extract( &tq->Queues.Priority, &the_thread->RBNode );
_RBTree_Insert(
&tq->Queues.Priority,
&the_thread->RBNode,
_Thread_queue_Compare_priority,
false
);
}
void _Thread_queue_Enqueue(
Thread_queue_Control *the_thread_queue,
Thread_Control *the_thread,
Watchdog_Interval timeout
)
{
ISR_lock_Context lock_context;
Thread_blocking_operation_States sync_state;
#if defined(RTEMS_MULTIPROCESSING)
if ( _Thread_MP_Is_receive( the_thread ) && the_thread->receive_packet )
the_thread = _Thread_MP_Allocate_proxy( the_thread_queue->state );
else
#endif
/*
* Set the blocking state for this thread queue in the thread.
*/
_Thread_Set_state( the_thread, the_thread_queue->state );
/*
* If the thread wants to timeout, then schedule its timer.
*/
if ( timeout ) {
_Watchdog_Initialize(
&the_thread->Timer,
_Thread_queue_Timeout,
the_thread->Object.id,
NULL
);
_Watchdog_Insert_ticks( &the_thread->Timer, timeout );
}
/*
* Now initiate the enqueuing and checking if the blocking operation
* should be completed or the thread has had its blocking condition
* satisfied before we got here.
*/
_Thread_queue_Acquire( &lock_context );
sync_state = the_thread_queue->sync_state;
the_thread_queue->sync_state = THREAD_BLOCKING_OPERATION_SYNCHRONIZED;
if ( sync_state == THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED ) {
/*
* Invoke the discipline specific enqueue method.
*/
if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_FIFO ) {
_Chain_Append_unprotected(
&the_thread_queue->Queues.Fifo,
&the_thread->Object.Node
);
} else { /* must be THREAD_QUEUE_DISCIPLINE_PRIORITY */
_Thread_Lock_set( the_thread, &_Thread_queue_Lock );
_Thread_Priority_set_change_handler(
the_thread,
_Thread_queue_Requeue_priority,
the_thread_queue
);
_RBTree_Insert(
&the_thread_queue->Queues.Priority,
&the_thread->RBNode,
_Thread_queue_Compare_priority,
false
);
}
the_thread->Wait.queue = the_thread_queue;
the_thread_queue->sync_state = THREAD_BLOCKING_OPERATION_SYNCHRONIZED;
_Thread_queue_Release( &lock_context );
} else {
/* Cancel a blocking operation due to ISR */
_Assert(
sync_state == THREAD_BLOCKING_OPERATION_TIMEOUT ||
sync_state == THREAD_BLOCKING_OPERATION_SATISFIED
);
_Thread_blocking_operation_Finalize( the_thread, &lock_context );
}
}
void _Thread_queue_Extract_with_return_code(
Thread_queue_Control *the_thread_queue,
Thread_Control *the_thread,
uint32_t return_code
)
{
ISR_lock_Context lock_context;
_Thread_queue_Acquire( &lock_context );
if ( !_States_Is_waiting_on_thread_queue( the_thread->current_state ) ) {
_Thread_queue_Release( &lock_context );
return;
}
if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_FIFO ) {
_Chain_Extract_unprotected( &the_thread->Object.Node );
} else { /* must be THREAD_QUEUE_DISCIPLINE_PRIORITY */
_RBTree_Extract(
&the_thread->Wait.queue->Queues.Priority,
&the_thread->RBNode
);
_Thread_Priority_restore_default_change_handler( the_thread );
_Thread_Lock_restore_default( the_thread );
}
the_thread->Wait.return_code = return_code;
/*
* We found a thread to unblock.
*
* NOTE: This is invoked with interrupts still disabled.
*/
_Thread_blocking_operation_Finalize( the_thread, &lock_context );
}
void _Thread_queue_Extract(
Thread_queue_Control *the_thread_queue,
Thread_Control *the_thread
)
{
_Thread_queue_Extract_with_return_code(
the_thread_queue,
the_thread,
the_thread->Wait.return_code
);
}
Thread_Control *_Thread_queue_Dequeue(
Thread_queue_Control *the_thread_queue
)
{
Thread_Control *the_thread;
ISR_lock_Context lock_context;
Thread_blocking_operation_States sync_state;
the_thread = NULL;
_Thread_queue_Acquire( &lock_context );
/*
* Invoke the discipline specific dequeue method.
*/
if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_FIFO ) {
if ( !_Chain_Is_empty( &the_thread_queue->Queues.Fifo ) ) {
the_thread = (Thread_Control *)
_Chain_Get_first_unprotected( &the_thread_queue->Queues.Fifo );
}
} else { /* must be THREAD_QUEUE_DISCIPLINE_PRIORITY */
RBTree_Node *first;
first = _RBTree_Get( &the_thread_queue->Queues.Priority, RBT_LEFT );
if ( first ) {
the_thread = THREAD_RBTREE_NODE_TO_THREAD( first );
_Thread_Priority_restore_default_change_handler( the_thread );
_Thread_Lock_restore_default( the_thread );
}
}
if ( the_thread == NULL ) {
/*
* We did not find a thread to unblock in the queue. Maybe the executing
* thread is about to block on this thread queue.
*/
sync_state = the_thread_queue->sync_state;
if ( (sync_state == THREAD_BLOCKING_OPERATION_TIMEOUT) ||
(sync_state == THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED) ) {
the_thread_queue->sync_state = THREAD_BLOCKING_OPERATION_SATISFIED;
the_thread = _Thread_Executing;
} else {
_Thread_queue_Release( &lock_context );
return NULL;
}
}
/*
* We found a thread to unblock.
*
* NOTE: This is invoked with interrupts still disabled.
*/
_Thread_blocking_operation_Finalize( the_thread, &lock_context );
return the_thread;
}