On Wed, 2015-07-29 at 14:27 +0100, Mark Rutland wrote:

On Wed, Jul 29, 2015 at 02:22:54PM +0100, Ian Campbell wrote:

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On Wed, 2015-07-29 at 20:07 +0900, Masahiro Yamada wrote:

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Hi Ian,


2015-07-27 19:35 GMT+09:00 Ian Campbell [off-list ref]:

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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.

I don't really have a preference either way.

I'm inclined to leave it, "visible to C sources" doesn't seem like that
much of an issue and IMHO the cure (kernel/dts/...) is worse than the
disease.

@@ -223,7 +223,7 @@ Example of a VE tile description (simplified)

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                /* 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?

#include allows you to use CPP in the file you're including, /include/
does not.

I would imagine we have to use #include in case the dtsi itself has
#include statements...

If it did, yes. I don't think vexpress-v2m-rs1.dtsi does, since it is using
/include/ today. I'm inclined to switch back to /include/ unless someone
objects.

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Please add include path for DTC too
so that both /include/ and #include are available.

... though that does not preclude adding it to the path for /include/.

Indeed, I've done that locally already.

Ian.