[U-Boot] [PATCH v2 2/3] dts: move device tree sources to arch/$(ARCH)/dts/

[Masahiro Yamada]

Hello Simon,


> Hi Masahiro,
> 
> On 4 February 2014 02:38, Masahiro Yamada <yamada.m at jp.panasonic.com> wrote:
> > Unlike Linux Kernel, U-Boot historically had *.dts files under
> > board/$(VENDOR)/dts/ and *.dtsi files under arch/$(ARCH)/dts/.
> >
> > I think arch/$(ARCH)/dts dicretory is a better location
> > to store both *.dts and *.dtsi files.
> >
> > For example, before this commit, board/xilinx/dts directory
> > had both MicroBlaze dts (microblaze-generic.dts) and
> > ARM dts (zynq-*.dts), which are totally unrelated.
> >
> > This commit moves *.dts to arch/$(ARCH)/dts/ directories,
> > allowing us to describe nicely mutiple DTBs generation in the next commit.
> 
> What is the motivation for this? I worry that we might end up with a
> lot of files in one directory.

We have only 35 .dtsi and .dts for ARM.
I think it will be OK at least until we have 500.

Linux v3.13 has 500 .dtsi and .dts files in arch/arm/boot/dts/
and they are still adding device trees to that directory.

I have no idea if they will keep going, or someone will scream and turn
around.

Anyway, when Linux guys someday invents a nice idea to work arond
increasing device trees, we can import it to U-Boot.
It should be easy for us because we already have a similar build system.

> One benefit of the current approach is
> that .dts files are split up by vendor. Even if we put the SoC .dtsi
> files in arch/arm, perhaps there is a benefit in leaving the board
> .dts files in board/<vendor>?

I don't like the idea to split up by vendor.

Now Xilinx has device trees both for ARM and Microblaze,
resulting in totally unrelated device trees in one directory.

What if Freescale decided to adopt device tree?
They support various boards on ARM, PowerPC, M68K.

Renesus is the same. They have ARM and SuperH boards.


On the other hand, different vendors can produce similar boards.
For example avionic design, which develops Tegra boards,
are using nVidia's sources.

When I saw  board/nvidia/common/common.mk
and board/avionic-design/*/Makefile, etc., I think we're screwed up
with <vendor> directory.

Best Regards
Masahiro Yamada