[U-Boot] [PATCH] kbuild: get back DTB at the top directory

[Simon Glass]

On 20 February 2014 22:34, Masahiro Yamada <yamada.m at jp.panasonic.com> wrote:
> Commit 6ab6b2af deleted ./u-boot.dtb because it was a copy
> of dts/dt.dtb.
>
> But Simon suggested to keep u-boot.dtb at the top directory
> because it is a build output.
>
> After discussions, we agreed on revival of ./u-boot.dtb.
>
> Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Tom Rini <trini at ti.com>

Acked-by: Simon Glass <sjg at chromium.org>

> ---
>
> Hello Simon,
>
> In our discussions, I memtioned to post version 4
> of "dts: re-write dts/Makefile more simply with Kbuild".
>
> But, before that, version 3 has been applied.
>
> Anyway, I promised to get back ./u-boot.dtb,
> so I'm posting this patch.
>
> To avoid a conflict with other patches,
> this patch is rebased on
> "Follow-up for Kbuild series: more misc targets and short logs" series.
> (And using Kbuild style to display short log)
>
> BTW, another question hit me when I was writing this patch.
> Please let me ask you a little more questions.
>
> I guess the reason why you want device tree at the top directory
> is Sandbox. Is this right?
> If so, I am 100% convinced and I'd like to suggest to modify
>
>     ALL-$(CONFIG_OF_SEPARATE) += u-boot.dtb u-boot-dtb.bin
>
> to
>
>     ALL-$(CONFIG_OF_SEPARATE) += u-boot-dtb.bin
>     ALL-$(CONFIG_OF_HOSTFILE) += u-boot.dtb
>
> Is this better?
> For CONFIG_OF_SEPARATE, I think there is no opportunity to use u-boot.dtb
> because we have u-boot-dtb.bin.

Well some build systems may take the u-boot.dtb and package it up with
U-Boot in a different way. Also they may look inside this file to find
out things about the board they are targeting. For example, you might
imagine a flash program which gets flash programming parameters from
this file so it knows how to flash the board.

I don't consider something in the dts/ directory to be a build product
really. I suspect one day we might support multiple .dtb files in
U-Boot and select between them based on a setting or a hardware
feature, and in that case perhaps everything will be put in a FIT, but
we are not there yet.

But for now I see the .dtb file as a first-class build product just
like the main U-Boot binary.

Regards,
Simon