Introduce arch_phys_memset which works like memset but on physical memory

The default implementation of this function is just memset, but other
implementations will be needed when physical memory isn't accessible by
U-Boot using normal addressing mechanisms.

Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/physmem.h b/include/physmem.h
new file mode 100644
index 0000000..03d3a78
--- /dev/null
+++ b/include/physmem.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ */
+
+/*
+ * These functions work like memset but operate on physical memory which may
+ * not be accessible directly.
+ *
+ * @param s	The physical address to start setting memory at.
+ * @param c	The character to set each byte of the region to.
+ * @param n	The number of bytes to set.
+ *
+ * @return	The physical address of the memory which was set.
+ */
+phys_addr_t arch_phys_memset(phys_addr_t s, int c, phys_size_t n);