Re: [PATCH 6/8] kbuild: consolidate Devicetree dtb build rules

From: Masahiro Yamada
Date: Sat Aug 25 2018 - 22:06:52 EST


Hi Rob,


2018-08-22 6:55 GMT+09:00 Rob Herring <robh@xxxxxxxxxx>:
> There is nothing arch specific about building dtb files other than their
> location under /arch/*/boot/dts/. Keeping each arch aligned is a pain.
> The dependencies and supported targets are all slightly different.
> Also, a cross-compiler for each arch is needed, but really the host
> compiler preprocessor is perfectly fine for building dtbs. Move the
> build rules to a common location and remove the arch specific ones. This
> is done in a single step to avoid warnings about overriding rules.
>
> The build dependencies had been a mixture of 'scripts' and/or 'prepare'.
> These pull in several dependencies some of which need a target compiler
> (specifically devicetable-offsets.h) and aren't needed to build dtbs.
> All that is really needed is dtc, so adjust the dependencies to only be
> dtc.
>
> This change enables support 'dtbs_install' on some arches which were
> missing the target.
>
> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Cc: Michal Marek <michal.lkml@xxxxxxxxxxx>
> Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michal Simek <monstr@xxxxxxxxx>
> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> Cc: Paul Burton <paul.burton@xxxxxxxx>
> Cc: James Hogan <jhogan@xxxxxxxxxx>
> Cc: Ley Foon Tan <lftan@xxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Chris Zankel <chris@xxxxxxxxxx>
> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
> Cc: linux-kbuild@xxxxxxxxxxxxxxx
> Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: uclinux-h8-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: linux-mips@xxxxxxxxxxxxxx
> Cc: nios2-dev@xxxxxxxxxxxxxxxxxxxxxx
> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> Cc: linux-xtensa@xxxxxxxxxxxxxxxx
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> Makefile | 30 ++++++++++++++++++++++++++++++
> arch/arc/Makefile | 6 ------
> arch/arm/Makefile | 20 +-------------------
> arch/arm64/Makefile | 17 +----------------
> arch/c6x/Makefile | 2 --
> arch/h8300/Makefile | 11 +----------
> arch/microblaze/Makefile | 4 +---
> arch/mips/Makefile | 15 +--------------
> arch/nds32/Makefile | 2 +-
> arch/nios2/Makefile | 7 -------
> arch/nios2/boot/Makefile | 4 ----
> arch/powerpc/Makefile | 3 ---
> arch/xtensa/Makefile | 12 +-----------
> scripts/Makefile | 1 -
> scripts/Makefile.lib | 2 +-
> 15 files changed, 38 insertions(+), 98 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index c13f8b85ba60..6d89e673f192 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1212,6 +1212,30 @@ kselftest-merge:
> $(srctree)/tools/testing/selftests/*/config
> +$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
>
> +# ---------------------------------------------------------------------------
> +# Devicetree files
> +
> +dtstree := $(wildcard arch/$(SRCARCH)/boot/dts)
> +
> +ifdef CONFIG_OF_EARLY_FLATTREE
> +
> +%.dtb %.dtb.S %.dtb.o: | dtc

I think the pipe operator is unnecessary
because Kbuild will descend to $(dtstree) anyway.


> + $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
> +
> +PHONY += dtbs
> +dtbs: | dtc

Ditto.


> + $(Q)$(MAKE) $(build)=$(dtstree)
> +
> +dtbs_install: dtbs
> + $(Q)$(MAKE) $(dtbinst)=$(dtstree)
> +
> +all: dtbs
> +
> +dtc:
> + $(Q)$(MAKE) $(build)=scripts/dtc
> +
> +endif
> +


arch/*/boot/dts/ are not only directories that
require dtc.


$ find drivers/ -name '*.dts'
drivers/staging/mt7621-dts/gbpc1.dts
drivers/staging/pi433/Documentation/devicetree/pi433-overlay.dts
drivers/of/unittest-data/overlay_12.dts
drivers/of/unittest-data/overlay.dts
drivers/of/unittest-data/overlay_5.dts
drivers/of/unittest-data/overlay_bad_symbol.dts
drivers/of/unittest-data/overlay_1.dts
drivers/of/unittest-data/overlay_bad_phandle.dts
drivers/of/unittest-data/overlay_2.dts
drivers/of/unittest-data/overlay_15.dts
drivers/of/unittest-data/overlay_10.dts
drivers/of/unittest-data/testcases.dts
drivers/of/unittest-data/overlay_6.dts
drivers/of/unittest-data/overlay_13.dts
drivers/of/unittest-data/overlay_4.dts
drivers/of/unittest-data/overlay_9.dts
drivers/of/unittest-data/overlay_3.dts
drivers/of/unittest-data/overlay_8.dts
drivers/of/unittest-data/overlay_7.dts
drivers/of/unittest-data/overlay_11.dts
drivers/of/unittest-data/overlay_0.dts
drivers/of/unittest-data/overlay_base.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7796.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7795.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7793.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7790.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7791.dts





dtc must be built before descending into any directory.





$ git clean -f -x
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- defconfig
drivers/gpu/drm/rcar-du/
HOSTCC scripts/basic/fixdep
HOSTCC scripts/kconfig/conf.o
YACC scripts/kconfig/zconf.tab.c
LEX scripts/kconfig/zconf.lex.c
HOSTCC scripts/kconfig/zconf.tab.o
HOSTLD scripts/kconfig/conf
*** Default configuration is based on 'multi_v7_defconfig'
#
# configuration written to .config
#
scripts/kconfig/conf --syncconfig Kconfig
CC kernel/bounds.s
CC arch/arm/kernel/asm-offsets.s
CALL scripts/checksyscalls.sh
<stdin>:1332:2: warning: #warning syscall io_pgetevents not implemented [-Wcpp]
CC scripts/mod/empty.o
HOSTCC scripts/mod/mk_elfconfig
MKELF scripts/mod/elfconfig.h
HOSTCC scripts/mod/modpost.o
CC scripts/mod/devicetable-offsets.s
UPD scripts/mod/devicetable-offsets.h
HOSTCC scripts/mod/file2alias.o
HOSTCC scripts/mod/sumversion.o
HOSTLD scripts/mod/modpost
HOSTCC scripts/kallsyms
HOSTCC scripts/conmakehash
HOSTCC scripts/sortextable
HOSTCC scripts/asn1_compiler
HOSTCC scripts/extract-cert
CC drivers/gpu/drm/rcar-du/rcar_lvds.o
AR drivers/gpu/drm/rcar-du/built-in.a
CC [M] drivers/gpu/drm/rcar-du/rcar_du_crtc.o
CC [M] drivers/gpu/drm/rcar-du/rcar_du_drv.o
CC [M] drivers/gpu/drm/rcar-du/rcar_du_encoder.o
CC [M] drivers/gpu/drm/rcar-du/rcar_du_group.o
CC [M] drivers/gpu/drm/rcar-du/rcar_du_kms.o
CC [M] drivers/gpu/drm/rcar-du/rcar_du_plane.o
CC [M] drivers/gpu/drm/rcar-du/rcar_du_of.o
make[2]: *** No rule to make target
'drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7790.dtb', needed by
'drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7790.dtb.S'. Stop.
Makefile:1721: recipe for target 'drivers/gpu/drm/rcar-du/' failed
make[1]: *** [drivers/gpu/drm/rcar-du/] Error 2
Makefile:286: recipe for target '__build_one_by_one' failed
make: *** [__build_one_by_one] Error 2








> diff --git a/scripts/Makefile b/scripts/Makefile
> index 61affa300d25..a716a6b10954 100644
> --- a/scripts/Makefile
> +++ b/scripts/Makefile
> @@ -39,7 +39,6 @@ build_unifdef: $(obj)/unifdef
> subdir-$(CONFIG_MODVERSIONS) += genksyms
> subdir-y += mod
> subdir-$(CONFIG_SECURITY_SELINUX) += selinux
> -subdir-$(CONFIG_DTC) += dtc
> subdir-$(CONFIG_GDB_SCRIPTS) += gdb
>
> # Let clean descend into subdirs


You need to 'dtc' here to clean-up scripts/dtc by "make mrproper".

subdir- += basic kconfig package gcc-plugins dtc







--
Best Regards
Masahiro Yamada