From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f169.google.com ([209.85.216.169]:54167 "EHLO mail-qc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758610Ab3HNSZG (ORCPT ); Wed, 14 Aug 2013 14:25:06 -0400 Received: by mail-qc0-f169.google.com with SMTP id m15so5109197qcq.14 for ; Wed, 14 Aug 2013 11:25:04 -0700 (PDT) Date: Wed, 14 Aug 2013 14:25:02 -0400 From: Tom Rini Subject: Re: [RFC] Best practices for hardware shipping device trees Message-ID: <20130814182502.GC2983@bill-the-cat> References: <20130814151345.GA2983@bill-the-cat> <520BB3E6.7000205@wwwdotorg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <520BB3E6.7000205@wwwdotorg.org> Sender: devicetree-owner@vger.kernel.org To: Stephen Warren , cross-distro@lists.linaro.org Cc: Tom Rini , devicetree@vger.kernel.org, Grant Likely , Rob Herring , Olof Johansson , Arnd Bergmann , Ian Campbell , Mark Rutland , Pawel Moll List-ID: On Wed, Aug 14, 2013 at 10:44:22AM -0600, Stephen Warren wrote: > On 08/14/2013 09:13 AM, Tom Rini wrote: > > Hey all, > > > > Do we have a document yet talking about the best practices for how we > > would like a hardware vendor to ship, store and possibly update a device > > tree, on the hardware? "However they like" seems likely to invite > > problems down the line with everyone trying their own thing. Thanks! > > I don't believe there's any written guidance, no. > > The initial guidance Grant gave (IIRC at the first Linaro Connect last > year, or perhaps the ARM workshop in Prague, or perhaps also in various > ARM kernel list threads?) was that the DTBs should be stored/accessed in > exactly the same way as the kernel, which on many systems implies it's a > file in /boot (although MTD partitions, ... are also possible kernel > locations). The idea here was to explicitly make upgrading the DTB as > easy as upgrading the kernel, and explicitly without having to upgrade > any firmware, since that's a more dangerous process in most cases. > > Now perhaps that advice was only intended to apply very early on when DT > was really new on ARM, and has "aged out" by now? If so, I don't recall > that every being explicitly mentioned or communicated later. [snip out a bit more of Stephen's answer] Yes, this notion certainly is the opposite of what was suggested on the cross-distro list, both as part of a "what should a bootloader provide to get commodity distros to support the board" thread and the "where should a device tree live in the filesystem" thread. Cc'ing them now because this is one of those things that feels like it needs solving, solving soon, and done in a way the least number of folks get surprised about it. -- Tom