From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann 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> References: <1464817421-8519-1-git-send-email-kraxel@redhat.com> <3336185.FIBLI6ezsy@wuerfel> <1464858870.24775.65.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <1464858870.24775.65.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Gerd Hoffmann Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.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-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Kumar Gala List-Id: devicetree@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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html