Add basic support for spinlocks (not currently used by anything)

ChangeLog

@@ -11469,3 +11469,8 @@
 	* include/nuttx/net/arp.h, include/nuttx/net/ioctl.h, net/netdev/netdev_ioctl.c,
 	  and ARP-related files: Add support for IOCTL commands to manage the
 	  ARP table (2016-02-08).
+	* ARMv7-A, ARMv7-R, and ARMv7-A: Add test-and-set logic and definitions
+	  needed to supports spinlocks (2016-02-09).
+	* include/nuttx/spinlock.h:  Add basic definitions for spinlocks.  Not yet
+	  used by NuttX (2016-02-09).
+

arch

@@ -1 +1 @@
-Subproject commit 5c9c3dc73e2ae5e87203801c6ab82e44a3f8fbec
+Subproject commit 958e4d09fc413d88893881eee612d901b779e057

configs

@@ -1 +1 @@
-Subproject commit df66c8b70c69689c9adf46c5d8188c9a5613e2e5
+Subproject commit 05856eb712badecadbdbd7803c868ebd0b2de451

include/nuttx/spinlock.h

@@ -0,0 +1,102 @@
+/****************************************************************************
+ * include/nuttx/spinlock.h
+ *
+ *   Copyright (C) 2016 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.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_SPINLOCK_H
+#define __INCLUDE_NUTTX_SPINLOCK_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <sched.h>
+
+/* The architecture specific spinlock.h header file must also provide the
+ * following:
+ *
+ *   SP_LOCKED   - A definition of the locked state value (usually 1)
+ *   SP_UNLOCKED - A definition of the unlocked state value (usually 0)
+ *   spinlock_t  - The type of a spinlock memory object.
+ *
+ * SP_LOCKED and SP_UNLOCKED must constants of type spinlock_t.
+ */
+
+#include <arch/spinlock.h>
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_testset
+ *
+ * Description:
+ *   Perform and atomic test and set operation on the provided spinlock.
+ *
+ *   This function must be provided via the architecture-specific logoic.
+ *
+ * Input Parameters:
+ *   lock - The address of spinlock object.
+ *
+ * Returned Value:
+ *   The spinlock is always locked upon return.  The value of previous value
+ *   of the spinlock variable is returned, either SP_LOCKED if the spinlock
+ *   as previously locked (meaning that the test-and-set operation failed to
+ *   obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
+ *   (meaning that we successfully obtained the lock)
+ *
+ ****************************************************************************/
+
+spinlock_t up_testset(FAR spinlock_t *lock);
+
+/****************************************************************************
+ * Name: spinlock
+ *
+ * Description:
+ *   Loop until the spinlock is successfully locked.
+ *
+ * Input Parameters:
+ *   lock - The address of spinlock object.
+ *
+ * Returned Value:
+ *   None.  When the function returned, the spinlocked was successfully
+ *   locked by this CPU.
+ *
+ ****************************************************************************/
+
+#define spinlock(l) while (up_testset(l) == SP_LOCKED) (void)sched_yield()
+
+#endif /* CONFIG_SIG_EVTHREAD && CONFIG_BUILD_FLAT */
+#endif /* __INCLUDE_NUTTX_SPINLOCK_H */