1 files changed, 129 insertions, 0 deletions
diff --git a/nuttx/graphics/nxconsole/nxcon_sem.c b/nuttx/graphics/nxconsole/nxcon_sem.c
new file mode 100644
index 000000000..4cf960971
--- /dev/null
+++ b/nuttx/graphics/nxconsole/nxcon_sem.c
@@ -0,0 +1,129 @@
+/****************************************************************************
+ * nuttx/graphics/nxconsole/nxcon_sem.c
+ *
+ *   Copyright (C) 2012 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 <unistd.h>
+#include <semaphore.h>
+#include <assert.h>
+#include <errno.h>
+
+#include "nxcon_internal.h"
+
+#ifdef CONFIG_DEBUG
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxcon_semwait and nxcon_sempost
+ *
+ * Description:
+ *   If debug is on, then lower level code may attempt console output while
+ *   we are doing console output!  In this case, we will toss the nested
+ *   output to avoid deadlocks and infinite loops.
+ *
+ * Input Parameters:
+ *   priv - Driver data structure
+ *
+ * Returned Value:
+ *   
+ *
+ ****************************************************************************/
+
+int nxcon_semwait(FAR struct nxcon_state_s *priv)
+{
+  pid_t me;
+  int ret;
+
+  /* Does I already hold the semaphore */
+
+  me = getpid();
+  if (priv->holder != me)
+    {
+      /* No.. then wait until the thread that does hold it is finished with it */
+
+      ret = sem_wait(&priv->exclsem);
+      if (ret == OK)
+        {
+          /* No I hold the semaphore */
+
+          priv->holder = me;
+        }
+      return ret;
+    }
+
+  /* Abort, abort, abort!  I have been re-entered */
+
+  set_errno(EBUSY);
+  return ERROR;
+}
+
+int nxcon_sempost(FAR struct nxcon_state_s *priv)
+{
+  pid_t me = getpid();
+
+  /* Make sure that I really hold the semaphore */
+
+  ASSERT(priv->holder == me);
+
+  /* Then let go of it */
+
+  priv->holder = NO_HOLDER;
+  return sem_post(&priv->exclsem);
+}
+
+#endif /* CONFIG_DEBUG */