[PATCH V5 1/2] kbuild: centralize .dts->.dtb rule

Stephen Warren
2012-10-31T22:10:41Z

From: Stephen Warren <swarren@nvidia.com>

All architectures that use cmd_dtc do so in the same way. Move the build
rule to a central location to avoid duplication.

Update Documentation/kbuild to remove the explicit call to cmd_dtc from
the example, now that the rule exists in a centralized location, and in
fact replace the example with a couple that still exist.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
v5: Update Documentation/kbuild
v4: No change.
v3: No change.
v2: New patch.
---
Documentation/kbuild/makefiles.txt | 21 +++++++++++++++------
arch/arm/boot/Makefile | 4 ----
arch/c6x/boot/Makefile | 3 ---
arch/openrisc/boot/Makefile | 3 ---
arch/powerpc/boot/Makefile | 4 ----
scripts/Makefile.lib | 3 +++
6 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index ec9ae67..a0b0671 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -1175,15 +1175,24 @@ When kbuild executes, the following steps are followed (roughly):
in an init section in the image. Platform code *must* copy the
blob to non-init memory prior to calling unflatten_device_tree().

+ To use this command, simply add *.dtb into obj-y or targets, or make
+ some other target depend on %.dtb
+
+ A central rule exists to create $(obj)/%.dtb from $(src)/dts/%.dts;
+ architecture Makefiles do no need to explicitly write out that rule.
+
Example:
- #arch/x86/platform/ce4100/Makefile
- clean-files := *dtb.S
+ #arch/arm/boot/Makefile
+ targets += $(dtb-y)
+ clean-files := *.dtb
+
+ #arch/powerpc/boot/Makefile
+ DTC_FLAGS ?= -p 1024

- DTC_FLAGS := -p 1024
- obj-y += foo.dtb.o
+ $(obj)/dtbImage.%: vmlinux $(wrapperbits) $(obj)/%.dtb
+ $(call if_changed,wrap,$*,,$(obj)/$*.dtb)

- $(obj)/%.dtb: $(src)/%.dts
- $(call cmd,dtc)
+ clean-files += ... *.dtb

--- 6.8 Custom kbuild commands

diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
index f2aa09e..208bb4c 100644
--- a/arch/arm/boot/Makefile
+++ b/arch/arm/boot/Makefile
@@ -61,10 +61,6 @@ endif

targets += $(dtb-y)

-# Rule to build device tree blobs
-$(obj)/%.dtb: $(src)/dts/%.dts FORCE
- $(call if_changed_dep,dtc)
-
$(obj)/dtbs: $(addprefix $(obj)/, $(dtb-y))

clean-files := *.dtb
diff --git a/arch/c6x/boot/Makefile b/arch/c6x/boot/Makefile
index 6891257..ad605fb 100644
--- a/arch/c6x/boot/Makefile
+++ b/arch/c6x/boot/Makefile
@@ -12,9 +12,6 @@ ifneq ($(DTB),)
obj-y += linked_dtb.o
endif

-$(obj)/%.dtb: $(src)/dts/%.dts FORCE
- $(call if_changed_dep,dtc)
-
quiet_cmd_cp = CP $< $@$2
cmd_cp = cat $< >$@$2 || (rm -f $@ && echo false)

diff --git a/arch/openrisc/boot/Makefile b/arch/openrisc/boot/Makefile
index 0995835..fd329bd 100644
--- a/arch/openrisc/boot/Makefile
+++ b/arch/openrisc/boot/Makefile
@@ -10,6 +10,3 @@ obj-y += $(BUILTIN_DTB)
clean-files := *.dtb.S

#DTC_FLAGS ?= -p 1024
-
-$(obj)/%.dtb: $(src)/dts/%.dts FORCE
- $(call if_changed_dep,dtc)
diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 6a15c96..90206f2 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -356,10 +356,6 @@ $(obj)/treeImage.initrd.%: vmlinux $(obj)/%.dtb $(wrapperbits)
$(obj)/treeImage.%: vmlinux $(obj)/%.dtb $(wrapperbits)
$(call if_changed,wrap,treeboot-$*,,$(obj)/$*.dtb)

-# Rule to build device tree blobs
-$(obj)/%.dtb: $(src)/dts/%.dts FORCE
- $(call if_changed_dep,dtc)
-
# If there isn't a platform selected then just strip the vmlinux.
ifeq (,$(image-y))
image-y := vmlinux.strip
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 0be6f11..425578e 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -266,6 +266,9 @@ $(obj)/%.dtb.S: $(obj)/%.dtb
quiet_cmd_dtc = DTC $@
cmd_dtc = $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) -d $(depfile) $<

+$(obj)/%.dtb: $(src)/dts/%.dts FORCE
+ $(call if_changed_dep,dtc)
+
# Bzip2
# ---------------------------------------------------------------------------

--
1.7.0.4