Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753048AbaKGO44 (ORCPT ); Fri, 7 Nov 2014 09:56:56 -0500 Received: from mail-lb0-f180.google.com ([209.85.217.180]:47761 "EHLO mail-lb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752021AbaKGO4y (ORCPT ); Fri, 7 Nov 2014 09:56:54 -0500 MIME-Version: 1.0 In-Reply-To: <20141107135931.376caf98@tock> References: <1415358849-25879-1-git-send-email-albeu@free.fr> <20141107120933.GA5487@leverpostej> <20141107135931.376caf98@tock> From: Rob Herring Date: Fri, 7 Nov 2014 08:56:32 -0600 Message-ID: Subject: Re: [PATCH] OF: Add support for built in FDT blob To: Alban Cc: Mark Rutland , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Rob Herring , "grant.likely@linaro.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 7, 2014 at 6:59 AM, Alban wrote: > On Fri, 7 Nov 2014 12:09:33 +0000 > Mark Rutland wrote: > >> Hi, >> >> On Fri, Nov 07, 2014 at 11:14:09AM +0000, Alban Bedel wrote: >> > Allow embedding an FDT blob in the kernel image, this is mostly >> > useful to run new kernels on boards with old bootloaders. >> >> I am very much not keen on embedding a DTB within a kernel. It's far >> nicer for the two to remain separate blobs, with a small shim to set >> up the DTB address. >> >> On ARM we have appended DTB for this purpose, which is at least better >> than embedding the DT inside of the kernel. > > I looked at that but that seemed quiet complicated to implement, not to > mention that it needed quiet a lot of arch specific code. On the other > hand having the DTB built in like this was trivial and would be portable > to every architecture, so that seemed like the best way to me. > >> What architecture and bootloader are you using that necessitate this? > > MIPS with an antic u-boot version patched by the board vendor to use > some non standard image format. Updating the boot loader is currently > not an option because of the lack of documentation for the board/SoC. MIPS and a few other arches already have built-in dtb support. We don't need another way to do it, but I would welcome any clean-up that makes it arch independent and available to any arch. While Mark is right, I could envision other uses such as embedding overlay dtbs in the kernel either for add-on boards or just as fixups. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/