From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Date: Thu, 16 Jul 2015 16:10:09 +0200 Subject: [U-Boot] [PATCH 00/20] arm: rpi: Enable USB and Ethernet driver model Raspberry Pi In-Reply-To: <55A495AA.6080609@wwwdotorg.org> References: <1436324032-17931-1-git-send-email-sjg@chromium.org> <55A0AAD3.2050302@wwwdotorg.org> <55A495AA.6080609@wwwdotorg.org> Message-ID: <20150716141009.GC29918@amd> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Mon 2015-07-13 22:52:58, Stephen Warren wrote: > On 07/11/2015 08:04 AM, Simon Glass wrote: > > Hi Stephen, > > > > On 10 July 2015 at 23:34, Stephen Warren wrote: > >> On 07/07/2015 08:53 PM, Simon Glass wrote: > >>> Raspberry Pi uses a DWC2 USB controller and a SMSC USB Ethernet adaptor. > >>> Neither of these currently support driver model. > >>> > >>> This series does the following: > >>> - Move Raspberry Pi to use device tree control (u-boot-dtb.bin instead of > >>> u-boot.bin) > >> > >> I'd strongly prefer not to do this. For one thing, it means we'd need > >> different U-Boot builds for each of the different RPi models, and we > >> currently don't need that (or perhaps we require users to create their > >> own u-boot-dtb.bin by choosing the right DTB to append). If it > > > > Why does device tree change how things work now? The get_board_rev() > > function currently deals with this. It doesn't look like rpi_board_rev > > is used anywhere else. > > Without a DT, the code is free to make all the board-rev-specific > decisions at run-time without external influence. > > With a DT, we either have to: > > a) Pick the DT for one particular board and use that everywhere, even if > it's incorrect for the actual board in use. Is that an option? I mean... if you can tolerate incorrect values for something, perhaps that something should not be in the dtb in the first place? > b) Build a different U-Boot + DTB image for each board-rev, and put the > correct one on the SD card. d) Build U-Boot + set of DTB images, then pick up the right one at the runtime? > Neither of those options seem like a good idea to me. Stuff that can be autodetected does not belong to the device tree... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html