MIPS: Add initial support for the Atheros AR71XX/AR724X/AR931X SoCs

This patch adds initial support for various Atheros SoCs based on the
MIPS 24Kc core. The following models are supported at the moment:

  - AR7130
  - AR7141
  - AR7161
  - AR9130
  - AR9132
  - AR7240
  - AR7241
  - AR7242

The current patch contains minimal support only, but the resulting
kernel can boot into user-space with using of an initramfs image on
various boards which are using these SoCs. Support for more built-in
devices and individual boards will be implemented in further patches.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1947/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/ath79/common.h b/arch/mips/ath79/common.h
new file mode 100644
index 0000000..612a6b5
--- /dev/null
+++ b/arch/mips/ath79/common.h
@@ -0,0 +1,26 @@
+/*
+ *  Atheros AR71XX/AR724X/AR913X common definitions
+ *
+ *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  Parts of this file are based on Atheros' 2.6.15 BSP
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ */
+
+#ifndef __ATH79_COMMON_H
+#define __ATH79_COMMON_H
+
+#include <linux/types.h>
+#include <linux/init.h>
+
+#define ATH79_MEM_SIZE_MIN	(2 * 1024 * 1024)
+#define ATH79_MEM_SIZE_MAX	(128 * 1024 * 1024)
+
+void ath79_clocks_init(void);
+void ath79_ddr_wb_flush(unsigned int reg);
+
+#endif /* __ATH79_COMMON_H */