pylibfdt: move pylibfdt to scripts/dtc/pylibfdt and refactor makefile

The pylibfdt is used by dtoc (and, indirectly by binman), but there
is no reason why it must be generated in the tools/ directory.

Recently, U-Boot switched over to the bundled DTC, and the directory
structure under scripts/dtc/ now mirrors the upstream DTC project.
So, scripts/dtc/pylibfdt is the best location.

I also rewrote the Makefile in a cleaner Kbuild style.

The scripts from the upstream have been moved as follows:

  lib/libfdt/pylibfdt/setup.py -> scripts/dtc/pylibfdt/setup.py
  lib/libfdt/pylibfdt/libfdt.i -> scripts/dtc/pylibfdt/libfdt.i_shipped

The .i_shipped is coped to .i during building because the .i must be
located in the objtree when we build it out of tree.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/Makefile b/Makefile
index 67f01ad..f94813d 100644
--- a/Makefile
+++ b/Makefile
@@ -1380,7 +1380,7 @@
 	$(call filechk,timestamp.h)
 
 checkbinman: tools
-	@if ! ( echo 'import libfdt' | ( PYTHONPATH=tools $(PYTHON) )); then \
+	@if ! ( echo 'import libfdt' | ( PYTHONPATH=scripts/dtc/pylibfdt $(PYTHON) )); then \
 		echo >&2; \
 		echo >&2 '*** binman needs the Python libfdt library.'; \
 		echo >&2 '*** Either install it on your system, or try:'; \
diff --git a/scripts/Makefile.spl b/scripts/Makefile.spl
index 49b27ac..065bb25 100644
--- a/scripts/Makefile.spl
+++ b/scripts/Makefile.spl
@@ -257,7 +257,7 @@
 $(obj)/$(SPL_BIN).dtb: dts/dt.dtb $(objtree)/tools/fdtgrep FORCE
 	$(call if_changed,fdtgrep)
 
-pythonpath = PYTHONPATH=tools
+pythonpath = PYTHONPATH=scripts/dtc/pylibfdt
 
 quiet_cmd_dtocc = DTOC C  $@
 cmd_dtocc = $(pythonpath) $(srctree)/tools/dtoc/dtoc -d $(obj)/$(SPL_BIN).dtb -o $@ platdata
@@ -381,7 +381,7 @@
 endif
 
 checkdtoc: tools
-	@if ! ( echo 'import libfdt' | ( PYTHONPATH=tools $(PYTHON) )); then \
+	@if ! ( echo 'import libfdt' | ( PYTHONPATH=scripts/dtc/pylibfdt $(PYTHON) )); then \
 		echo '*** dtoc needs the Python libfdt library. Either '; \
 		echo '*** install it on your system, or try:'; \
 		echo '***'; \
diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
index 2a48022..f4a16ed 100644
--- a/scripts/dtc/Makefile
+++ b/scripts/dtc/Makefile
@@ -29,3 +29,6 @@
 
 # generated files need to be cleaned explicitly
 clean-files	:= dtc-lexer.lex.c dtc-parser.tab.c dtc-parser.tab.h
+
+# Added for U-Boot
+subdir-y += pylibfdt
diff --git a/scripts/dtc/pylibfdt/.gitignore b/scripts/dtc/pylibfdt/.gitignore
new file mode 100644
index 0000000..033f23d
--- /dev/null
+++ b/scripts/dtc/pylibfdt/.gitignore
@@ -0,0 +1,4 @@
+/_libfdt.so
+/libfdt.py
+/libfdt.pyc
+/libfdt_wrap.c
diff --git a/scripts/dtc/pylibfdt/Makefile b/scripts/dtc/pylibfdt/Makefile
new file mode 100644
index 0000000..01d5e0f
--- /dev/null
+++ b/scripts/dtc/pylibfdt/Makefile
@@ -0,0 +1,30 @@
+# Unfortunately setup.py below cannot handle srctree being ".." which it often
+# is. It fails with an error like:
+# Fatal error: can't create build/temp.linux-x86_64-2.7/../lib/libfdt/fdt.o:
+#    No such file or directory
+# To fix this, use an absolute path.
+LIBFDT_srcdir = $(abspath $(srctree)/$(src)/../libfdt)
+
+include $(LIBFDT_srcdir)/Makefile.libfdt
+
+# Unfortunately setup.py (or actually the Python distutil implementation) puts
+# files into the same directory as the .i file. We cannot touch the source
+# directory, so we "ship" .i file into the objtree.
+PYLIBFDT_srcs = $(addprefix $(LIBFDT_srcdir)/,$(LIBFDT_SRCS)) \
+		$(obj)/libfdt.i
+
+quiet_cmd_pymod = PYMOD   $@
+      cmd_pymod = unset CC; unset CROSS_COMPILE; unset CFLAGS;\
+		LDFLAGS="$(HOSTLDFLAGS)" \
+		VERSION="u-boot-$(UBOOTVERSION)" \
+		CPPFLAGS="$(HOSTCFLAGS) -I$(LIBFDT_srcdir)" OBJDIR=$(obj) \
+		SOURCES="$(PYLIBFDT_srcs)" \
+		SWIG_OPTS="-I$(LIBFDT_srcdir) -I$(LIBFDT_srcdir)/.." \
+		$(PYTHON) $< --quiet build_ext --inplace
+
+$(obj)/_libfdt.so: $(src)/setup.py $(PYLIBFDT_srcs) FORCE
+	$(call if_changed,pymod)
+
+always += _libfdt.so
+
+clean-files += libfdt.i _libfdt.so libfdt.py libfdt_wrap.c
diff --git a/lib/libfdt/pylibfdt/libfdt.i b/scripts/dtc/pylibfdt/libfdt.i_shipped
similarity index 100%
rename from lib/libfdt/pylibfdt/libfdt.i
rename to scripts/dtc/pylibfdt/libfdt.i_shipped
diff --git a/lib/libfdt/pylibfdt/setup.py b/scripts/dtc/pylibfdt/setup.py
similarity index 100%
rename from lib/libfdt/pylibfdt/setup.py
rename to scripts/dtc/pylibfdt/setup.py
diff --git a/tools/.gitignore b/tools/.gitignore
index 5293d44..6a487d2 100644
--- a/tools/.gitignore
+++ b/tools/.gitignore
@@ -1,4 +1,3 @@
-/_libfdt.so
 /atmel_pmecc_params
 /bin2header
 /bmp_logo
@@ -17,9 +16,6 @@
 /img2srec
 /kwboot
 /lib/
-/libfdt.py
-/libfdt.pyc
-/libfdt_wrap.c
 /mips-relocs
 /mkenvimage
 /mkexynosspl
diff --git a/tools/Makefile b/tools/Makefile
index 5db2a54..2b87e18 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -63,15 +63,6 @@
 			fdt_empty_tree.c fdt_addresses.c fdt_overlay.c \
 			fdt_region.c
 
-# Unfortunately setup.py below cannot handle srctree being ".." which it often
-# is. It fails with an error like:
-# Fatal error: can't create build/temp.linux-x86_64-2.7/../lib/libfdt/fdt.o:
-#    No such file or directory
-# To fix this, use an absolute path.
-libfdt_tree := $(shell readlink -f $(srctree)/lib/libfdt)
-
-LIBFDT_SRCS := $(addprefix $(libfdt_tree)/, $(LIBFDT_CSRCS))
-LIBFDT_SWIG := $(addprefix $(libfdt_tree)/, pylibfdt/libfdt.i)
 LIBFDT_OBJS := $(addprefix lib/libfdt/, $(patsubst %.c, %.o, $(LIBFDT_CSRCS)))
 
 RSA_OBJS-$(CONFIG_FIT_SIGNATURE) := $(addprefix lib/rsa/, \
@@ -123,23 +114,6 @@
 fit_info-objs   := $(dumpimage-mkimage-objs) fit_info.o
 fit_check_sign-objs   := $(dumpimage-mkimage-objs) fit_check_sign.o
 
-# Unfortunately setup.py (or actually the Python distutil implementation)
-# puts files into the same directory as the .i file. We cannot touch the source
-# directory, so we copy the .i file into the tools/ build subdirectory before
-# calling setup. This directory is safe to write to. This ensures that we get
-# all three files in $(obj)/tools: _libfdt.so, libfdt.py and libfdt_wrap.c
-# The latter is a temporary file which we could actually remove.
-tools/_libfdt.so: $(LIBFDT_SRCS) $(LIBFDT_SWIG)
-	$(Q)cp $(LIBFDT_SWIG) tools/.
-	$(Q)unset CC; \
-	unset CROSS_COMPILE; \
-	LDFLAGS="$(HOSTLDFLAGS)" CFLAGS= VERSION="u-boot-$(UBOOTVERSION)" \
-		CPPFLAGS="$(_hostc_flags)" OBJDIR=tools \
-		SOURCES="$(LIBFDT_SRCS) tools/libfdt.i" \
-		SWIG_OPTS="-I$(srctree)/lib/libfdt -I$(srctree)/lib" \
-		$(PYTHON) $(libfdt_tree)/pylibfdt/setup.py --quiet build_ext \
-			--build-lib tools
-
 ifneq ($(CONFIG_MX23)$(CONFIG_MX28),)
 # Add CONFIG_MXS into host CFLAGS, so we can check whether or not register
 # the mxsimage support within tools/mxsimage.c .
@@ -231,10 +205,6 @@
 
 always := $(hostprogs-y)
 
-# Build a libfdt Python module if swig is available
-# Use 'sudo apt-get install swig libpython-dev' to enable this
-always += $(if $(shell which swig 2> /dev/null),_libfdt.so)
-
 # Generated LCD/video logo
 LOGO_H = $(objtree)/include/bmp_logo.h
 LOGO_DATA_H = $(objtree)/include/bmp_logo_data.h
diff --git a/tools/binman/binman.py b/tools/binman/binman.py
index 09dc36a..e75a59d 100755
--- a/tools/binman/binman.py
+++ b/tools/binman/binman.py
@@ -21,7 +21,7 @@
     sys.path.insert(0, os.path.join(our_path, dirname))
 
 # Bring in the libfdt module
-sys.path.insert(0, 'tools')
+sys.path.insert(0, 'scripts/dtc/pylibfdt')
 
 # Also allow entry-type modules to be brought in from the etype directory.
 sys.path.insert(0, os.path.join(our_path, 'etype'))