From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947200Ab3BHVY3 (ORCPT ); Fri, 8 Feb 2013 16:24:29 -0500 Received: from mail-ob0-f170.google.com ([209.85.214.170]:45260 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1947150Ab3BHVY2 (ORCPT ); Fri, 8 Feb 2013 16:24:28 -0500 Message-ID: <51156D09.7060401@gmail.com> Date: Fri, 08 Feb 2013 15:24:25 -0600 From: Rob Herring User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Grant Likely CC: Stephen Warren , Michal Marek , Grant Likely , Srinivas KANDAGATLA , Mark Brown , Scott Wood , Sam Ravnborg , linux-kernel@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, Stephen Warren Subject: Re: [PATCH V8] kbuild: create a rule to run the pre-processor on *.dts files References: <1360091188-24063-1-git-send-email-swarren@wwwdotorg.org> <20130208144527.0D8DD3E2C01@localhost> In-Reply-To: <20130208144527.0D8DD3E2C01@localhost> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/08/2013 08:45 AM, Grant Likely wrote: > On Tue, 5 Feb 2013 12:06:28 -0700, Stephen Warren wrote: >> From: Stephen Warren >> >> Create cmd_dtc_cpp to run the C pre-processor on *.dts file before >> passing them to dtc for final compilation. This allows the use of #define >> and #include within the .dts file. >> >> Acked-by: Simon Glass >> Acked-by: Jean-Christophe PLAGNIOL-VILLARD >> Acked-by: Michal Marek >> Acked-by: Srinivas Kandagatla >> Signed-off-by: Stephen Warren > > I've applied this and was going to push it out, but I've just thought of > a problem that could be a show stopper. Once a dtsp file includes a C > header, the contents of that header become part of the Device Tree ABI. > If someone changes that file (ie. to renumber a series of #defines) then > that will break the binding. We need a way to protect against that. > Someone changing a .h file may make the assumption that it is only > kernel internal and won't realize that it has external implications. > > I'm thinking that any dts includes need to be treated in the same way as > userspace headers. We could put them into include/uapi and piggy back on > the protection already afforded by that directory, or come up with > something new. Any thoughts? Also, we would never be able to separate the dts files from the kernel tree without some separation. Rob