From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pali =?utf-8?q?Roh=C3=A1r?= Subject: Re: [PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry Date: Wed, 25 Nov 2015 23:00:59 +0100 Message-ID: <201511252300.59976@pali> References: <20150713131902.GH26485@atomide.com> <201511252244.28797@pali> <17689711.DsQsCiDFAN@wuerfel> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart724251494.rz7WDksilK"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17689711.DsQsCiDFAN@wuerfel> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Tony Lindgren , Pavel Machek , Frank Rowand , "devicetree@vger.kernel.org" , Russell King - ARM Linux , Laura Abbott , Grant Likely , Rob Herring , Will Deacon , Ivaylo Dimitrov , Sebastian Reichel , Andreas =?utf-8?q?F=C3=A4rber?= , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org List-Id: linux-omap@vger.kernel.org --nextPart724251494.rz7WDksilK Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Wednesday 25 November 2015 22:51:00 Arnd Bergmann wrote: > On Wednesday 25 November 2015 22:44:28 Pali Roh=C3=A1r 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? >=20 > 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. >=20 Ok. So there is no better solution. With some hacks we can use U-Boot as=20 3rd stage bootloader. But this is not useful for debugging or=20 developing... Ideal "wrapper" solution would be to compile wrapper and linux zImage=20 and then glue them together to one binary. Something like internal linux=20 uncompress code which translate atags to dt. > 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. >=20 Yes, proprietary/closed applications are problems which we cannot fix=20 (without rewriting them). New applications could use new "proper" interface. But without that=20 interface we cannot do that. =2D-=20 Pali Roh=C3=A1r pali.rohar@gmail.com --nextPart724251494.rz7WDksilK Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEABECAAYFAlZWL5sACgkQi/DJPQPkQ1KN9ACgqFuY1Bltbq3pNCRXmHYto6go 5BAAni99JGn/sd8QiaEv/jGPEKzxcB77 =mEtj -----END PGP SIGNATURE----- --nextPart724251494.rz7WDksilK--