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>

8 files changed, 23 insertions, 0 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index a9e15403434e..e091300b2045 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -395,4 +395,10 @@ config SIGNATURE
           Digital signature verification. Currently only RSA is supported.
           Implementation is done using GnuPG MPI library
 
+#
+# libfdt files, only selected if needed.
+#
+config LIBFDT
+        bool
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 8c31a0cb75e9..2f2be5a8734c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -130,6 +130,11 @@ obj-$(CONFIG_GENERIC_STRNLEN_USER) += strnlen_user.o
 
 obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
 
+libfdt_files = fdt.o fdt_ro.o fdt_wip.o fdt_rw.o fdt_sw.o fdt_strerror.o
+$(foreach file, $(libfdt_files), \
+        $(eval CFLAGS_$(file) = -I$(src)/../scripts/dtc/libfdt))
+lib-$(CONFIG_LIBFDT) += $(libfdt_files)
+
 hostprogs-y     := gen_crc32table
 clean-files     := crc32table.h
 
diff --git a/lib/fdt.c b/lib/fdt.c
new file mode 100644
index 000000000000..97f20069fc37
--- /dev/null
+++ b/lib/fdt.c
@@ -0,0 +1,2 @@
+#include <linux/libfdt_env.h>
+#include "../scripts/dtc/libfdt/fdt.c"
diff --git a/lib/fdt_ro.c b/lib/fdt_ro.c
new file mode 100644
index 000000000000..f73c04ea7be4
--- /dev/null
+++ b/lib/fdt_ro.c
@@ -0,0 +1,2 @@
+#include <linux/libfdt_env.h>
+#include "../scripts/dtc/libfdt/fdt_ro.c"
diff --git a/lib/fdt_rw.c b/lib/fdt_rw.c
new file mode 100644
index 000000000000..0c1f0f4a4b13
--- /dev/null
+++ b/lib/fdt_rw.c
@@ -0,0 +1,2 @@
+#include <linux/libfdt_env.h>
+#include "../scripts/dtc/libfdt/fdt_rw.c"
diff --git a/lib/fdt_strerror.c b/lib/fdt_strerror.c
new file mode 100644
index 000000000000..8713e3ff4707
--- /dev/null
+++ b/lib/fdt_strerror.c
@@ -0,0 +1,2 @@
+#include <linux/libfdt_env.h>
+#include "../scripts/dtc/libfdt/fdt_strerror.c"
diff --git a/lib/fdt_sw.c b/lib/fdt_sw.c
new file mode 100644
index 000000000000..9ac7e50c76ce
--- /dev/null
+++ b/lib/fdt_sw.c
@@ -0,0 +1,2 @@
+#include <linux/libfdt_env.h>
+#include "../scripts/dtc/libfdt/fdt_sw.c"
diff --git a/lib/fdt_wip.c b/lib/fdt_wip.c
new file mode 100644
index 000000000000..45b3fc3d3ba1
--- /dev/null
+++ b/lib/fdt_wip.c
@@ -0,0 +1,2 @@
+#include <linux/libfdt_env.h>
+#include "../scripts/dtc/libfdt/fdt_wip.c"