From: Arnd Bergmann <arnd@arndb.de>
To: Pali =?ISO-8859-1?Q?Roh=E1r?= <pali.rohar@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>, Pavel Machek <pavel@ucw.cz>,
        Frank Rowand <frowand.list@gmail.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Russell King - ARM Linux <linux@arm.linux.org.uk>,
        Laura Abbott <lauraa@codeaurora.org>,
        Grant Likely <grant.likely@linaro.org>,
        Rob Herring <robherring2@gmail.com>, Will Deacon <will.deacon@arm.com>,
        Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>,
        Sebastian Reichel <sre@debian.org>,
        Andreas =?ISO-8859-1?Q?F=E4rber?= <afaerber@suse.de>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org
Subject: Re: [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry
Date: Wed, 25 Nov 2015 22:51 +0100
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On Wednesday 25 November 2015 22:44:28 Pali Roh?r wrote:
> 
> Arnd, my question about proper solution reminds... Proprietary 
> bootloader which cannot be replaced (e.g. it is signed or do unknown 
> magic) provides information to booted kernel via custom specific ATAGs 
> fields. How userspace could properly read those custom information from 
> bootloader?

The typical solution for nonstandard bootloaders is to have a boot wrapper
like the one from https://github.com/zonque/pxa-impedance-matcher that
translates whatever information we have at the bootloader level into
DT properties.

As I understand, the reason we are not doing that here is that we also
have proprietary user space that we can't fix to look in a different
place, i.e. the interface is between the bootloader and some user
binary, not bootloader to kernel.

	Arnd
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