From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39259C04AB5 for ; Tue, 4 Jun 2019 00:19:38 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AC6DD26077 for ; Tue, 4 Jun 2019 00:19:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC6DD26077 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45HsxM4FfXzDqbs for ; Tue, 4 Jun 2019 10:19:35 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=permerror (mailfrom) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=benh@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45Hsw00lnzzDqDN for ; Tue, 4 Jun 2019 10:18:23 +1000 (AEST) Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x540ICHI017518; Mon, 3 Jun 2019 19:18:13 -0500 Message-ID: <73f8650b2bcb861d79cad675d6c8e1b92f4d4d11.camel@kernel.crashing.org> Subject: Re: [PATCH kernel] prom_init: Fetch flatten device tree from the system firmware From: Benjamin Herrenschmidt To: Segher Boessenkool , Alexey Kardashevskiy Date: Tue, 04 Jun 2019 10:18:12 +1000 In-Reply-To: <20190603234247.GQ31586@gate.crashing.org> References: <20190501034221.18437-1-aik@ozlabs.ru> <20190530193736.GC31586@gate.crashing.org> <43f037c57eed8ad2175470c940917dced947bb70.camel@kernel.crashing.org> <20190602232330.GN31586@gate.crashing.org> <7fc6cd5e-ddd6-4028-b4ef-7bdcd6db69d0@ozlabs.ru> <20190603234247.GQ31586@gate.crashing.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, Suraj Jitindar Singh , David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, 2019-06-03 at 18:42 -0500, Segher Boessenkool wrote: > Hi! > > On Mon, Jun 03, 2019 at 12:56:26PM +1000, Alexey Kardashevskiy wrote: > > On 03/06/2019 09:23, Segher Boessenkool wrote: > > > > So I go for the simple one and agree with Alexey's idea. > > > > > > When dealing with a whole device tree you have to know about the > > > various > > > dynamically generated nodes and props, and handle each > > > appropriately. > > > > The code I am changing fetches the device tree and build an fdt. > > What is > > that special knowledge in this context you are talking about? > > Things like /options are dynamically generated. They are generated before we do the call to extract the fdt, what's the problem there ? > I thought you would just be able to reuse some FDT parsing code to > implement my suggested new interface. Maybe that was too optimistic. No, the idea is to have SLOF re-flatten it's live tree and hand us a blob. At least that's my understanding. Ben.