Re: [PATCH v2] dtb: Create a common home for cross-architecture dtsi files.

[Rob Herring]

On Wed, Jul 29, 2015 at 8:22 AM, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> On Wed, 2015-07-29 at 20:07 +0900, Masahiro Yamada wrote:
>> Hi Ian,
>>
>>
>> 2015-07-27 19:35 GMT+09:00 Ian Campbell <ian.campbell@xxxxxxxxxx>:
>> > Commit 9ccd608070b6 "arm64: dts: add device tree for ARM SMM-A53x2 on
>> > LogicTile Express 20MG" added a new dts file to arch/arm64 which
>> > included "../../../../arm/boot/dts/vexpress-v2m-rs1.dtsi", i.e. a
>> > .dtsi supplied by arch/arm.
>> >
>> > Unfortunately this causes some issues for the split device tree
>> > repository[0], since things get moved around there. In that context
>> > the new .dts ends up at src/arm64/arm/vexpress-v2f-1xv7-ca53x2.dts
>> > while the include is at src/arm/vexpress-v2m-rs1.dtsi.
>> >
>> > The sharing of the .dtsi is legitimate since the baseboard is the same
>> > for various vexpress systems whatever processor they use.
>> >
>> > Rather than using ../../ tricks to pickup .dtsi files from another
>> > arch this patch creates a new directory include/dt-dtsi as a
>> > home for such cross-arch .dtsi files, arranges for it to be in the
>> > include path when the .dts files are processed by cpp and switches the
>>
>>
>> "include/dt-dtsi/"  can be referenced from normal C sources.
>>
>> I think another possible home for cross-arch DTSI is "kernel/dts/".
>> This directory can be hidden from C sources.
>
> I suppose, I don't really mind and will follow the direction of the other
> DTB maintainers. It doesn't seem like a big deal to me.

Seems fine to me. We might think of other things to put here that are
not includes. Overlays perhaps?

>
>> >@@ -223,7 +223,7 @@ Example of a VE tile description (simplified)
>> >                 /* Active high IRQ 0 is connected to GIC's SPI0 */
>> >                 interrupt-map = <0 0 0 &gic 0 0 4>;
>> >
>> > -               /include/ "vexpress-v2m-rs1.dtsi"
>> > +               #include <arm/vexpress-v2m-rs1.dtsi>
>> >         };
>> >  };
>>
>>
>>
>> You do not have to replace /include/ with #include,
>> if you add the include path for DTC.
>
> Ah, I looked for this but -i is not documented in the man page.
>
> Is there any reason to prefer one over the other?

Yes, so you don't force the use of the C preprocessor.

Rob
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