From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753112AbcFBJxT (ORCPT ); Thu, 2 Jun 2016 05:53:19 -0400 Received: from mout.kundenserver.de ([212.227.126.134]:49472 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750978AbcFBJxR (ORCPT ); Thu, 2 Jun 2016 05:53:17 -0400 From: Arnd Bergmann To: Gerd Hoffmann Cc: linux-arm-kernel@lists.infradead.org, Mark Rutland , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Pawel Moll , Ian Campbell , Russell King , open list , Eric Anholt , Rob Herring , linux-rpi-kernel@lists.infradead.org, Kumar Gala Subject: Re: [PATCH 09/32] bcm2837-rpi-3-b.dts for 32bit arm Date: Thu, 02 Jun 2016 11:53:13 +0200 Message-ID: <4795604.XAe8xnhung@wuerfel> User-Agent: KMail/5.1.3 (Linux/4.4.0-22-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <1464858870.24775.65.camel@redhat.com> References: <1464817421-8519-1-git-send-email-kraxel@redhat.com> <3336185.FIBLI6ezsy@wuerfel> <1464858870.24775.65.camel@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:WpmmgJYwqkPp9fdtET+y306PvKAE2ZaT/WMqwQUpNrqMfGHwINU NxeDvhTtceuMoQ/u7d7EQrah1qA6b5S036oCigsN2irzgWYp/JUa++tBcybdL3/iufvI+ID 3sSUF/onY6huzWqDHFaFk39EpdbfdaUDtSl0B5fd+ffJ6joAgizHBlOSxthXFesWdXyG/L5 NYQ3G5Sjs2ZXm6tudmqcA== X-UI-Out-Filterresults: notjunk:1;V01:K0:oO7orgKFWuY=:G44eo61D0327bVqJPV8/0J FPKH6Iv0KfRhPV5+62aX0k4BiD2CgtIvmuLetDFszjOLqITc5B8KBkCXLv/OAPHMigBPxWwU8 atwZ2MblNjTeojHeImru7yc8BFIbZcj/Oc4A5ofX2c0UYtqjVpgUvXQD9aZHzFvOy9rp+CIg/ vuXBqqXqRCe8Alos8RS9/dmdiYWjhIIyHcrkrNOZrrNT9bRlYs+NTO6+42W65mfmB8ahAN5cD u5Q7DsX6mXf+/AqgMvH471hczhjJ1mgbbwsTJN2/gr9aabSBYZUX/ZY+FNOtudzMC9xDV6Qru Ed7pIwCP/60QwCbr1OubbRKOO4jum70Y3aGzq+S5sdZuy5AgNd+QJ9MWOzSTGI+I8xMDEkYLy fD6t980MdsbHlJIVuCqry2Vqt7k3GpHlRCIuSOPa3/MSv1dGr3U59hV7wCDpluQEST+BxHPfM Ubr0DRJhtz34V10eM3s/cWLKnj8xqCdivqWBydGOze/xj8B9Yciy+jsG/kgqTFgy6aVfhCAh+ kF2O+ma8oV8WVZIt+4RFbURI75QFTaqH+39iaSX5mIrocqkd6kDdwdSuysE+HhU+l7XfYBkUq olfW03uyggGNddZuYSFBXATjEWIfEi55LsMK2fcIRzTx3rNfWQwb0w5XgJj+x2Rr4aCZ2kC/3 xP85jM7LVmVwMme0Z+OvT4UqJi7IASrULEmoENEN9PLrl9ZFR23bh/0kmX6vrRmcSqvpLL4dI X4XeD249iAZeEtgG Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, June 2, 2016 11:14:30 AM CEST Gerd Hoffmann wrote: > Hi, > > > > Well, it just includes the arm64 version as-is, so we don't have > > > duplication. I'm open to suggestions to how handle this better. > > > > > > Symbolic link? > > > > > > Reference to ../../../arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts > > > directly in the Makefile? > > > > > > I've seen arch/arm/boot/dts/Makefile uses globs on *.dts, so I suspect > > > the later wouldn't be that straight forward. > > > > It's just weird that the arm64 file includes the .dtsi files from arch/arm/ > > and is then again included back from another file there. > > > > I can see two possible ways to handle this better: > > > > - leave the complete set of bcm2837 files in arch/arm and then have one > > reference from arch/arm64 per .dts that refers to just that file. > > So basically do it the other way around. Would be a bit less messy > indeed. > > > - come up with a rule to also build the .dtb files in arch/arm64 when > > we run 'make dtbs' for arch/arm and leave this file there. The argument > > that one could use the same dtb with a 32-bit kernel should basically > > hold true for any arm64 system, it's not specific to rpi-3 really. > > Yes, in theory. No, in practice. As far I know the rpi3 is the only > 64bit soc where a almost identical 32bit version exists, so running > 32bit kernels on a 64bit processor actually happens in practice and I > expect this to continue. If you want create sdcard images which run on > any rpi variant this is pretty much the only reasonable way to do it. I think the Allwinner A64 and the Samsung s5p6818 are other examples for this, where the initial run of boards all run 32-bit kernels for much of the same reasons. If users want to run a 32-bit distro on rpi-3 and on e.g. orange-pi, I don't see why they wouldn't also run the same binary on A64. Arnd