Re: Moving ARM dts files

From: Rob Herring <robh@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: "Andrew Lunn" <andrew@lunn.ch>,
	"Alexandre Belloni" <alexandre.belloni@bootlin.com>,
	"Tony Lindgren" <tony@atomide.com>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Liviu Dudau" <liviu.dudau@arm.com>,
	"Michal Simek" <michal.simek@xilinx.com>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Tom Rini" <trini@konsulko.com>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Kevin Hilman" <khilman@kernel.org>,
	"Gregory CLEMENT" <gregory.clement@bootlin.com>,
	"Alexander Graf" <agraf@suse.de>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"ARM-SoC Maintainers" <arm@kernel.org>,
	"Joel Stanley" <joel@jms.id.au>,
	"Andy Gross" <andy.gross@linaro.org>,
	devicetree@vger.kernel.org,
	"Architecture Mailman List" <boot-architecture@lists.linaro.org>,
	"Jason Cooper" <jason@lakedaemon.net>,
	"Simon Horman" <horms@verge.net.au>,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
	<linux-arm-kernel@lists.infradead.org>,
	"Grant Likely" <Grant.Likely@arm.com>,
	"Maxime Coquelin" <mcoquelin.stm32@gmail.com>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Andreas Färber" <afaerber@suse.de>,
	"Daniel Mack" <daniel@zonque.org>
Subject: Re: Moving ARM dts files
Date: Fri, 7 Dec 2018 08:57:06 -0600	[thread overview]
Message-ID: <CAL_JsqJuH4=Bq9ok3Trz4GgLam7gqWW5-gyHpG1XbShtQQuSJg@mail.gmail.com> (raw)
In-Reply-To: <20181206200652.GB3084@sirena.org.uk>

On Thu, Dec 6, 2018 at 2:07 PM Mark Brown <broonie@kernel.org> wrote:
>
> On Thu, Dec 06, 2018 at 01:06:43PM -0600, Rob Herring wrote:
> > On Thu, Dec 6, 2018 at 7:32 AM Andreas Färber <afaerber@suse.de> wrote:
>
> > > I'd be okay with distinguishing source vs. install location. Due to the
> > > issue I mention below (and more) we can't use install_dtbs for openSUSE
> > > and had to reimplement it, which we'd need to (and can) adjust.
>
> > What would be needed for dtbs_install to work? arm64 needs to support
> > a flat install? If it doesn't work for Debian or openSUSE, I'm not
> > sure why we have it. So I'd like to make it work.
>
> Correct me if I'm wrong but as far as the flat vs directory thing goes
> isn't the issue that this winds up being a rename for an existing 32 bit
> system?  If you just install the dtbs in the default location then a
> bootloader or whatever that is hard coded to look for foo-bar.dtb won't
> see the new foo/foo-bar.dtb (or whatever) and will continue to use the
> old binary.  It's not the fact that that it's in a directory, it's the
> fact that the bootloader sees the name it needs to look for change (if
> it's looking on a filesystem at all).

Correct.

> This isn't a problem for arm64 as
> the location isn't changing, it's used directories from day one.

The kernel may have used directories, but that's not what the distros
did according to Andreas:

> We already had that discussion for arm64 because Debian chose to ignore
> the kernel-installed subdirectories and installed .dtb files into a flat
> directory, which collided with openSUSE sticking to the kernel choice.

So are the distros different or who changed to align? That's not clear
from this thread.

> The issues with the existing install_dtbs sounded unrelated to this.

Maybe, what are the issues? We can't change the source layout
transparently if dtbs_install is not being used.

My question here is whether a flat install is useful on arm64. We can
either have a kconfig variable that arm32 sets to do flat installs or
it could be some command line make variable and then any user can pick
what they want for any arch.

Rob

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