ARM: Orion5x - Restore parts of io.h, with rework

Commit 4d5fc58 (ARM: remove bunch of
now unused mach/io.h files) removed the orion5x io.h. Unfortunately,
this is still needed for the definition of IO_SPACE_LIMIT which
overrides the default 64K. All Orion based systems have 1Mbyte of IO
space per PCI[e] bus, and try to request_resource() this size. Orion5x
has two such PCI buses.

It is likely that the original, removed version, was broken. This
version might be less broken. However, it has not been tested on
hardware with a PCI card, let alone hardware with a PCI card with IO
capabilities.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/Kconfig

@@ -589,6 +589,7 @@ config ARCH_ORION5X
 	select PCI
 	select ARCH_REQUIRE_GPIOLIB
 	select GENERIC_CLOCKEVENTS
+	select NEED_MACH_IO_H
 	select PLAT_ORION
 	help
 	  Support for the following Marvell Orion 5x series SoCs:

arch/arm/mach-orion5x/include/mach/io.h

@@ -0,0 +1,22 @@
+/*
+ * arch/arm/mach-orion5x/include/mach/io.h
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __ASM_ARCH_IO_H
+#define __ASM_ARCH_IO_H
+
+#include <mach/orion5x.h>
+#include <asm/sizes.h>
+
+#define IO_SPACE_LIMIT		SZ_2M
+static inline void __iomem *__io(unsigned long addr)
+{
+	return (void __iomem *)(addr + ORION5X_PCIE_IO_VIRT_BASE);
+}
+
+#define __io(a)			 __io(a)
+#endif