1 files changed, 109 insertions, 0 deletions
diff --git a/nuttx/sched/sched_lock.c b/nuttx/sched/sched_lock.c
new file mode 100644
index 0000000000..344d3d75b1
--- /dev/null
+++ b/nuttx/sched/sched_lock.c
@@ -0,0 +1,109 @@
+/************************************************************
+ * sched_lock.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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 <sys/types.h>
+#include <sched.h>
+#include <assert.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Type Declarations
+ ************************************************************/
+
+/************************************************************
+ * Global Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Function Prototypes
+ ************************************************************/
+
+/************************************************************
+ * Private Functionss
+ ************************************************************/
+
+/************************************************************
+ * Public Functions
+ ************************************************************/
+
+/************************************************************
+ * Name:  sched_lock
+ *
+ * Description:
+ *   This function disables context switching by disabling
+ *   addition of new tasks to the g_readytorun task list.
+ *   The task that calls this function will be the only task
+ *   that is allowed to run until it either calls 
+ *   sched_unlock() (the appropriate number of times) or
+ *   until it blocks itself.
+ *
+ * Inputs
+ *   None
+ *
+ * Return Value:
+ *   OK on success; ERROR on failure
+ *
+ ************************************************************/
+
+STATUS sched_lock(void)
+{
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+  /* Check for some special cases:  (1) rtcb may be NULL only during
+   * early boot-up phases, and (2) sched_lock() should have no
+   * effect if called from the interrupt level.
+   */
+
+  if (rtcb && !up_interrupt_context())
+    {
+     ASSERT(rtcb->lockcount < MAX_LOCK_COUNT);
+     rtcb->lockcount++;
+    }
+  return OK;
+}