From 7cc8d6c3b1a207684892d207055ceff9f37d5731 Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Tue, 2 Nov 1999 21:48:15 +0000
Subject: Split core mutex and semaphore handlers into separate files.

---
 cpukit/score/src/coremutexsurrender.c | 139 ++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 cpukit/score/src/coremutexsurrender.c

(limited to 'cpukit/score/src/coremutexsurrender.c')

diff --git a/cpukit/score/src/coremutexsurrender.c b/cpukit/score/src/coremutexsurrender.c
new file mode 100644
index 0000000000..b7f38eb2b0
--- /dev/null
+++ b/cpukit/score/src/coremutexsurrender.c
@@ -0,0 +1,139 @@
+/*
+ *  Mutex Handler
+ *
+ *  DESCRIPTION:
+ *
+ *  This package is the implementation of the Mutex Handler.
+ *  This handler provides synchronization and mutual exclusion capabilities.
+ *
+ *  COPYRIGHT (c) 1989-1998.
+ *  On-Line Applications Research Corporation (OAR).
+ *  Copyright assigned to U.S. Government, 1994.
+ *
+ *  The license and distribution terms for this file may be
+ *  found 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>
+
+/*
+ *  _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;
+
+  /*
+   *  The following code allows a thread (or ISR) other than the thread
+   *  which acquired the mutex to release that mutex.  This is only
+   *  allowed when the mutex in quetion is FIFO or simple Priority
+   *  discipline.  But Priority Ceiling or Priority Inheritance mutexes
+   *  must be released by the thread which acquired them.
+   */ 
+
+  if ( !_Objects_Are_ids_equal(
+           _Thread_Executing->Object.id, the_mutex->holder_id ) ) {
+
+    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:
+        return( CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE );
+        break;
+    }
+  }
+
+  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 defined(RTEMS_MULTIPROCESSING)
+    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 
+#endif
+    {
+
+      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 );
+}
+
-- 
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