Add framework to support task groups

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5562 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 107 insertions, 0 deletions

diff --git a/nuttx/sched/group_join.c b/nuttx/sched/group_join.c
new file mode 100644
index 000000000..987c1ba87
--- /dev/null
+++ b/nuttx/sched/group_join.c
@@ -0,0 +1,107 @@
+/*****************************************************************************
+ * sched/group_join.c
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Included Files
+ *****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <assert.h>
+#include <debug.h>
+
+#include "os_internal.h"
+
+#ifdef HAVE_TASK_GROUP
+
+/*****************************************************************************
+ * Pre-processor Definitions
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Private Types
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Private Data
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Private Functions
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Public Functions
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Name: group_join
+ *
+ * Description:
+ *   Copy the group structure reference from one TCB to another, incrementing
+ *   the refrence count on the group.  This function is called when a pthread
+ *   is produced within the task group so that the pthread can share the
+ *   resources of the task group.
+ *
+ * Parameters:
+ *   tcb - The TCB of the new "child" task that need to join the group.
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ * - The parent task from which the group will be inherited is the task at
+ *   the thead of the ready to run list.
+ * - Called during thread creation in a safe context.  No special precautions
+ *   are required here.
+ *
+ *****************************************************************************/
+
+void group_join(FAR _TCB *tcb)
+{
+  FAR _TCB *ptcb = (FAR _TCB *)g_readytorun.head;
+
+  DEBUGASSERT(ptcb && tcb && ptcb->group && !tcb->group);
+
+  /* Copy the group reference from the parent to the child, incrementing the
+   * reference count.
+   */
+
+  tcb->group = ptcb->group;
+  ptcb->group->tg_crefs++;
+}
+
+#endif /* HAVE_TASK_GROUP */