1 files changed, 76 insertions, 0 deletions
diff --git a/cpukit/score/src/schedulercbsunblock.c b/cpukit/score/src/schedulercbsunblock.c
new file mode 100644
index 0000000000..0f417d8c9e
--- /dev/null
+++ b/cpukit/score/src/schedulercbsunblock.c
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 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.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+void _Scheduler_CBS_Unblock(
+  Thread_Control    *the_thread
+)
+{
+  Scheduler_CBS_Per_thread *sched_info;
+  Scheduler_CBS_Server *serv_info;
+  Priority_Control new_priority;
+
+  _Scheduler_EDF_Enqueue(the_thread);
+  /* TODO: flash critical section? */
+
+  sched_info = (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
+  serv_info = (Scheduler_CBS_Server *) sched_info->cbs_server;
+
+  /*
+   * Late unblock rule for deadline-driven tasks. The remaining time to
+   * deadline must be sufficient to serve the remaining computation time
+   * without increased utilization of this task. It might cause a deadline
+   * miss of another task.
+   */
+  if (serv_info) {
+    time_t deadline = serv_info->parameters.deadline;
+    time_t budget = serv_info->parameters.budget;
+    time_t deadline_left = the_thread->cpu_time_budget;
+    time_t budget_left = the_thread->real_priority -
+                           _Watchdog_Ticks_since_boot;
+
+    if ( deadline*budget_left > budget*deadline_left ) {
+      /* Put late unblocked task to background until the end of period. */
+      new_priority = the_thread->Start.initial_priority;
+      if ( the_thread->real_priority != new_priority )
+        the_thread->real_priority = new_priority;
+      if ( the_thread->current_priority != new_priority )
+        _Thread_Change_priority(the_thread, new_priority, true);
+    }
+  }
+
+  /*
+   *  If the thread that was unblocked is more important than the heir,
+   *  then we have a new heir.  This may or may not result in a
+   *  context switch.
+   *
+   *  Normal case:
+   *    If the current thread is preemptible, then we need to do
+   *    a context switch.
+   *  Pseudo-ISR case:
+   *    Even if the thread isn't preemptible, if the new heir is
+   *    a pseudo-ISR system task, we need to do a context switch.
+   */
+  if ( _Scheduler_Is_priority_higher_than( the_thread->current_priority,
+       _Thread_Heir->current_priority)) {
+    _Thread_Heir = the_thread;
+    if ( _Thread_Executing->is_preemptible ||
+         the_thread->current_priority == 0 )
+      _Thread_Dispatch_necessary = true;
+  }
+}