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-rw-r--r--c/src/exec/score/src/coremutex.c330
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diff --git a/c/src/exec/score/src/coremutex.c b/c/src/exec/score/src/coremutex.c
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+++ b/c/src/exec/score/src/coremutex.c
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+/*
+ * Mutex Handler
+ *
+ * DESCRIPTION:
+ *
+ * This package is the implementation of the Mutex Handler.
+ * This handler provides synchronization and mutual exclusion capabilities.
+ *
+ * COPYRIGHT (c) 1989-1997.
+ * On-Line Applications Research Corporation (OAR).
+ * Copyright assigned to U.S. Government, 1994.
+ *
+ * The license and distribution terms for this file may in
+ * the file LICENSE in this distribution or at
+ * http://www.OARcorp.com/rtems/license.html.
+ *
+ * $Id$
+ */
+
+#include <rtems/system.h>
+#include <rtems/score/isr.h>
+#include <rtems/score/coremutex.h>
+#include <rtems/score/states.h>
+#include <rtems/score/thread.h>
+#include <rtems/score/threadq.h>
+
+/*PAGE
+ *
+ * _CORE_mutex_Initialize
+ *
+ * This routine initializes a mutex at create time and set the control
+ * structure according to the values passed.
+ *
+ * Input parameters:
+ * the_mutex - the mutex control block to initialize
+ * the_class - the API class of the object
+ * the_mutex_attributes - the mutex attributes specified at create time
+ * initial_lock - mutex initial lock or unlocked status
+ * proxy_extract_callout - MP specific extract callout
+ *
+ * Output parameters: NONE
+ */
+
+void _CORE_mutex_Initialize(
+ CORE_mutex_Control *the_mutex,
+ Objects_Classes the_class,
+ CORE_mutex_Attributes *the_mutex_attributes,
+ unsigned32 initial_lock,
+ Thread_queue_Extract_callout proxy_extract_callout
+)
+{
+
+/* Add this to the RTEMS environment later ?????????
+ rtems_assert( initial_lock == CORE_MUTEX_LOCKED ||
+ initial_lock == CORE_MUTEX_UNLOCKED );
+ */
+
+ the_mutex->Attributes = *the_mutex_attributes;
+ the_mutex->lock = initial_lock;
+
+ if ( initial_lock == CORE_MUTEX_LOCKED ) {
+ the_mutex->nest_count = 1;
+ the_mutex->holder = _Thread_Executing;
+ the_mutex->holder_id = _Thread_Executing->Object.id;
+ _Thread_Executing->resource_count++;
+ } else {
+ the_mutex->nest_count = 0;
+ the_mutex->holder = NULL;
+ the_mutex->holder_id = 0;
+ }
+
+ _Thread_queue_Initialize(
+ &the_mutex->Wait_queue,
+ the_class,
+ _CORE_mutex_Is_fifo( the_mutex_attributes ) ?
+ THREAD_QUEUE_DISCIPLINE_FIFO : THREAD_QUEUE_DISCIPLINE_PRIORITY,
+ STATES_WAITING_FOR_MUTEX,
+ proxy_extract_callout,
+ CORE_MUTEX_TIMEOUT
+ );
+}
+
+/*PAGE
+ *
+ * _CORE_mutex_Seize
+ *
+ * This routine attempts to allocate a mutex to the calling thread.
+ *
+ * Input parameters:
+ * the_mutex - pointer to mutex control block
+ * id - id of object to wait on
+ * wait - TRUE if wait is allowed, FALSE otherwise
+ * timeout - number of ticks to wait (0 means forever)
+ *
+ * Output parameters: NONE
+ *
+ * INTERRUPT LATENCY:
+ * available
+ * wait
+ */
+
+void _CORE_mutex_Seize(
+ CORE_mutex_Control *the_mutex,
+ Objects_Id id,
+ boolean wait,
+ Watchdog_Interval timeout
+)
+{
+ Thread_Control *executing;
+ ISR_Level level;
+
+ executing = _Thread_Executing;
+ switch ( the_mutex->Attributes.discipline ) {
+ case CORE_MUTEX_DISCIPLINES_FIFO:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
+ break;
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
+ if ( executing->current_priority <
+ the_mutex->Attributes.priority_ceiling) {
+ executing->Wait.return_code = CORE_MUTEX_STATUS_CEILING_VIOLATED;
+ return;
+ }
+ }
+ executing->Wait.return_code = CORE_MUTEX_STATUS_SUCCESSFUL;
+ _ISR_Disable( level );
+ if ( ! _CORE_mutex_Is_locked( the_mutex ) ) {
+ the_mutex->lock = CORE_MUTEX_LOCKED;
+ the_mutex->holder = executing;
+ the_mutex->holder_id = executing->Object.id;
+ the_mutex->nest_count = 1;
+ executing->resource_count++;
+ _ISR_Enable( level );
+ switch ( the_mutex->Attributes.discipline ) {
+ case CORE_MUTEX_DISCIPLINES_FIFO:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
+ /* already the highest priority */
+ break;
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
+ if ( the_mutex->Attributes.priority_ceiling <
+ executing->current_priority ) {
+ _Thread_Change_priority(
+ the_mutex->holder,
+ the_mutex->Attributes.priority_ceiling,
+ FALSE
+ );
+ }
+ }
+ return;
+ }
+
+ if ( _Objects_Are_ids_equal(
+ _Thread_Executing->Object.id, the_mutex->holder_id ) ) {
+ if ( _CORE_mutex_Is_nesting_allowed( &the_mutex->Attributes ) )
+ the_mutex->nest_count++;
+ else
+ executing->Wait.return_code = CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED;
+
+ _ISR_Enable( level );
+ return;
+ }
+
+ if ( !wait ) {
+ _ISR_Enable( level );
+ executing->Wait.return_code = CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT;
+ return;
+ }
+
+ _Thread_queue_Enter_critical_section( &the_mutex->Wait_queue );
+ executing->Wait.queue = &the_mutex->Wait_queue;
+ executing->Wait.id = id;
+ _ISR_Enable( level );
+
+ switch ( the_mutex->Attributes.discipline ) {
+ case CORE_MUTEX_DISCIPLINES_FIFO:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
+ break;
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
+ if ( the_mutex->holder->current_priority > executing->current_priority ) {
+ _Thread_Change_priority(
+ the_mutex->holder,
+ executing->current_priority,
+ FALSE
+ );
+ }
+ break;
+ }
+
+ _Thread_queue_Enqueue( &the_mutex->Wait_queue, timeout );
+
+ if ( _Thread_Executing->Wait.return_code == CORE_MUTEX_STATUS_SUCCESSFUL ) {
+ switch ( the_mutex->Attributes.discipline ) {
+ case CORE_MUTEX_DISCIPLINES_FIFO:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
+ break;
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
+ if ( the_mutex->Attributes.priority_ceiling <
+ executing->current_priority ) {
+ _Thread_Change_priority(
+ executing,
+ the_mutex->Attributes.priority_ceiling,
+ FALSE
+ );
+ };
+ break;
+ }
+ }
+}
+
+/*
+ * _CORE_mutex_Surrender
+ *
+ * DESCRIPTION:
+ *
+ * This routine frees a unit to the mutex. If a task was blocked waiting for
+ * a unit from this mutex, then that task will be readied and the unit
+ * given to that task. Otherwise, the unit will be returned to the mutex.
+ *
+ * Input parameters:
+ * the_mutex - the mutex to be flushed
+ * id - id of parent mutex
+ * api_mutex_mp_support - api dependent MP support actions
+ *
+ * Output parameters:
+ * CORE_MUTEX_STATUS_SUCCESSFUL - if successful
+ * core error code - if unsuccessful
+ */
+
+CORE_mutex_Status _CORE_mutex_Surrender(
+ CORE_mutex_Control *the_mutex,
+ Objects_Id id,
+ CORE_mutex_API_mp_support_callout api_mutex_mp_support
+)
+{
+ Thread_Control *the_thread;
+ Thread_Control *executing;
+
+ executing = _Thread_Executing;
+
+ if ( !_Objects_Are_ids_equal(
+ _Thread_Executing->Object.id, the_mutex->holder_id ) )
+ return( CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE );
+
+ the_mutex->nest_count--;
+
+ if ( the_mutex->nest_count != 0 )
+ return( CORE_MUTEX_STATUS_SUCCESSFUL );
+
+ _Thread_Executing->resource_count--;
+ the_mutex->holder = NULL;
+ the_mutex->holder_id = 0;
+
+ /*
+ * Whether or not someone is waiting for the mutex, an
+ * inherited priority must be lowered if this is the last
+ * mutex (i.e. resource) this task has.
+ */
+
+ switch ( the_mutex->Attributes.discipline ) {
+ case CORE_MUTEX_DISCIPLINES_FIFO:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY:
+ break;
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
+ case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
+ if ( executing->resource_count == 0 &&
+ executing->real_priority != executing->current_priority ) {
+ _Thread_Change_priority( executing, executing->real_priority, TRUE );
+ }
+ break;
+ }
+
+
+ if ( ( the_thread = _Thread_queue_Dequeue( &the_mutex->Wait_queue ) ) ) {
+
+ if ( !_Objects_Is_local_id( the_thread->Object.id ) ) {
+
+ the_mutex->holder = NULL;
+ the_mutex->holder_id = the_thread->Object.id;
+ the_mutex->nest_count = 1;
+
+ ( *api_mutex_mp_support)( the_thread, id );
+
+ } else {
+
+ the_mutex->holder = the_thread;
+ the_mutex->holder_id = the_thread->Object.id;
+ the_thread->resource_count++;
+ the_mutex->nest_count = 1;
+
+ /*
+ * No special action for priority inheritance or priority ceiling
+ * because the_thread is guaranteed to be the highest priority
+ * thread waiting for the mutex.
+ */
+ }
+ } else
+ the_mutex->lock = CORE_MUTEX_UNLOCKED;
+
+ return( CORE_MUTEX_STATUS_SUCCESSFUL );
+}
+
+/*PAGE
+ *
+ * _CORE_mutex_Flush
+ *
+ * This function a flushes the mutex's task wait queue.
+ *
+ * Input parameters:
+ * the_mutex - the mutex to be flushed
+ * remote_extract_callout - function to invoke remotely
+ * status - status to pass to thread
+ *
+ * Output parameters: NONE
+ */
+
+void _CORE_mutex_Flush(
+ CORE_mutex_Control *the_mutex,
+ Thread_queue_Flush_callout remote_extract_callout,
+ unsigned32 status
+)
+{
+ _Thread_queue_Flush(
+ &the_mutex->Wait_queue,
+ remote_extract_callout,
+ status
+ );
+}
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