of/lib: Allow scripts/dtc/libfdt to be used from kernel code

libfdt is part of the device tree support in scripts/dtc/libfdt.  For
some platforms that use the Device Tree, we want to be able to edit
the flattened device tree form.

We don't want to burden kernel builds that do not require it, so we
gate compilation of libfdt files with CONFIG_LIBFDT.  So if it is
needed, you need to do this in your Kconfig:

	select LIBFDT

And in the Makefile of the code using libfdt something like:

ccflags-y := -I$(src)/../../../scripts/dtc/libfdt

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.kernel.org
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/libfdt_env.h b/include/linux/libfdt_env.h
new file mode 100644
index 000000000000..01508c7b8c81
--- /dev/null
+++ b/include/linux/libfdt_env.h
@@ -0,0 +1,13 @@
+#ifndef _LIBFDT_ENV_H
+#define _LIBFDT_ENV_H
+
+#include <linux/string.h>
+
+#include <asm/byteorder.h>
+
+#define fdt32_to_cpu(x) be32_to_cpu(x)
+#define cpu_to_fdt32(x) cpu_to_be32(x)
+#define fdt64_to_cpu(x) be64_to_cpu(x)
+#define cpu_to_fdt64(x) cpu_to_be64(x)
+
+#endif /* _LIBFDT_ENV_H */