[PATCH v3 6/9] kbuild: consolidate Devicetree dtb build rules

[Masahiro Yamada]

2018-09-12 0:40 GMT+09:00 Rob Herring <robh at kernel.org>:
> On Mon, Sep 10, 2018 at 10:04 AM Rob Herring <robh at kernel.org> wrote:
>>
>> 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.
>
> [...]
>
>> @@ -1215,6 +1215,33 @@ kselftest-merge:
>>                 $(srctree)/tools/testing/selftests/*/config
>>         +$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
>>
>> +# ---------------------------------------------------------------------------
>> +# Devicetree files
>> +
>> +ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/boot/dts/),)
>> +dtstree := arch/$(SRCARCH)/boot/dts
>> +endif
>> +
>> +ifdef CONFIG_OF_EARLY_FLATTREE
>
> This can be true when dtstree is unset. So this line should be this
> instead to fix the 0-day reported error:
>
> ifneq ($(dtstree),)
>
>> +
>> +%.dtb : scripts_dtc
>> +       $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
>> +
>> +PHONY += dtbs dtbs_install
>> +dtbs: scripts_dtc
>> +       $(Q)$(MAKE) $(build)=$(dtstree)
>> +
>> +dtbs_install: dtbs
>> +       $(Q)$(MAKE) $(dtbinst)=$(dtstree)
>> +
>> +all: dtbs
>> +
>> +endif


Ah, right.
Even x86 can enable OF and OF_UNITTEST.



Another solution might be,
guard it by 'depends on ARCH_SUPPORTS_OF'.



This is actually what ACPI does.

menuconfig ACPI
        bool "ACPI (Advanced Configuration and Power Interface) Support"
        depends on ARCH_SUPPORTS_ACPI
         ...





-- 
Best Regards
Masahiro Yamada