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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Wed, 20 Jan 2021 17:58:05 +0900
Message-ID: <CAK7LNATPSBrmSC_if+6sK0pwi1ksBZ7RXK1mndj1AGCX3gkj+g@mail.gmail.com>
Subject: Re: [PATCH V5 4/5] kbuild: Add support to build overlays (%.dtbo)
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Frank Rowand <frowand.list@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
        Michal Marek <michal.lkml@markovi.net>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        DTML <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        David Gibson <david@gibson.dropbear.id.au>,
        Bill Mills <bill.mills@linaro.org>,
        Anmar Oueja <anmar.oueja@linaro.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>
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Precedence: bulk

On Wed, Jan 20, 2021 at 4:07 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> Add support for building DT overlays (%.dtbo). The overlay's source file
> will have the usual extension, i.e. .dts, though the blob will have
> .dtbo extension to distinguish it from normal blobs.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  .gitignore               | 3 +--
>  Makefile                 | 4 ++--
>  scripts/Makefile.dtbinst | 3 +++
>  scripts/Makefile.lib     | 4 +++-
>  4 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/.gitignore b/.gitignore
> index d01cda8e1177..0458c36f3cb2 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -17,8 +17,7 @@
>  *.bz2
>  *.c.[012]*.*
>  *.dt.yaml
> -*.dtb
> -*.dtb.S
> +*.dtb*


Personally, I prefer adding .dtbo explicitly


>  *.dwo
>  *.elf
>  *.gcno
> diff --git a/Makefile b/Makefile
> index 9e73f82e0d86..b84f5e0b46ab 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1334,7 +1334,7 @@ endif
>
>  ifneq ($(dtstree),)
>
> -%.dtb: include/config/kernel.release scripts_dtc
> +%.dtb %.dtbo: include/config/kernel.release scripts_dtc
>         $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@


No, this is wrong because it does not work
as grouped targets.

You need to separate them.


%.dtb: include/config/kernel.release scripts_dtc
         $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@

%.dtbo: include/config/kernel.release scripts_dtc
         $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@


See GNU make manual.


"Pattern rules may have more than one target; however, every target
must contain a % character.
Pattern rules are always treated as grouped targets"

https://www.gnu.org/software/make/manual/html_node/Pattern-Intro.html


>  PHONY += dtbs dtbs_install dtbs_check
> @@ -1816,7 +1816,7 @@ clean: $(clean-dirs)
>         @find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
>                 \( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
>                 -o -name '*.ko.*' \
> -               -o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
> +               -o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
>                 -o -name '*.dwo' -o -name '*.lst' \
>                 -o -name '*.su' -o -name '*.mod' \
>                 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
> diff --git a/scripts/Makefile.dtbinst b/scripts/Makefile.dtbinst
> index 50d580d77ae9..ba01f5ba2517 100644
> --- a/scripts/Makefile.dtbinst
> +++ b/scripts/Makefile.dtbinst
> @@ -29,6 +29,9 @@ quiet_cmd_dtb_install = INSTALL $@
>  $(dst)/%.dtb: $(obj)/%.dtb
>         $(call cmd,dtb_install)
>
> +$(dst)/%.dtbo: $(obj)/%.dtbo
> +       $(call cmd,dtb_install)
> +
>  PHONY += $(subdirs)
>  $(subdirs):
>         $(Q)$(MAKE) $(dtbinst)=$@ dst=$(patsubst $(obj)/%,$(dst)/%,$@)
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 213677a5ed33..30bc0a8e0087 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -86,7 +86,9 @@ extra-$(CONFIG_OF_ALL_DTBS)   += $(dtb-)
>
>  ifneq ($(CHECK_DTBS),)
>  extra-y += $(patsubst %.dtb,%.dt.yaml, $(dtb-y))
> +extra-y += $(patsubst %.dtbo,%.dt.yaml, $(dtb-y))
>  extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtb,%.dt.yaml, $(dtb-))
> +extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtbo,%.dt.yaml, $(dtb-))
>  endif
>
>  # Add subdir path
> @@ -324,7 +326,7 @@ cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ;
>                 -d $(depfile).dtc.tmp $(dtc-tmp) ; \
>         cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
>
> -$(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
> +$(obj)/%.dtb $(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
>         $(call if_changed_dep,dtc)


Same here.

You need to duplicate the rules everywhere, unfortunately.


>  DT_CHECKER ?= dt-validate
> --
> 2.25.0.rc1.19.g042ed3e048af
>


-- 
Best Regards
Masahiro Yamada