Subject: Re: [PATCH] devicetree: Enable generation of __symbols__ in all dtb
 files
To: Rob Herring <robh@kernel.org>, Tom Rini <trini@konsulko.com>
References: <1502831736-28282-1-git-send-email-trini@konsulko.com>
 <CABGGiswpz6k4rnXk-3SLpwD5V8+zah-yaaB+yrrLofKY1eBx2w@mail.gmail.com>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Tero Kristo <t-kristo@ti.com>, Nishanth Menon <nm@ti.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>, Sekhar Nori <nsekhar@ti.com>,
        Rob Herring <robh+dt@kernel.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Michal Marek <mmarek@suse.com>,
        Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-kbuild@vger.kernel.org
From: Frank Rowand <frowand.list@gmail.com>
Message-ID: <59938E76.3010807@gmail.com>
Date: Tue, 15 Aug 2017 17:14:46 -0700
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On 08/15/17 15:36, Rob Herring wrote:
> On Tue, Aug 15, 2017 at 4:15 PM, Tom Rini <trini@konsulko.com> wrote:
>> With support for stacked overlays being part of libfdt it is now

< snip >

>> My proposal is that we do not want __symbols__ existence to be dependent
>> on some part of the kernel configuration for a number of reasons.
>> First, this is out of step with the rest of how dtbs are created today
>> and more importantly, thought about.  Today, all dtb content is
>> independent of CONFIG options.  If you build a dtb from a given kernel
>> tree, everyone will agree on the result.  This is part of the "contract"
>> on passing old kernels and new dtb files even.
> 
> Agree completely. I don't even like that building dtbs depends on the ARCH.

< snip >

I also agree that use of CONFIG options is a solution that I do not like.
It has always seemed that there is a bit of an impedence mismatch in that
we build a dtb in an environment that is configured for a specific board
and architecture.

Does anyone have any thoughts on another way to control whether or not a
given dtb or a given build of a dtb would contain the symbols needed for
overlays or not include the symbols?

-Frank