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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E843C433EF for ; Fri, 8 Jul 2022 09:47:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237806AbiGHJr4 (ORCPT ); Fri, 8 Jul 2022 05:47:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237803AbiGHJry (ORCPT ); Fri, 8 Jul 2022 05:47:54 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 33CF17E03B; Fri, 8 Jul 2022 02:47:52 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 32615D6E; Fri, 8 Jul 2022 02:47:52 -0700 (PDT) Received: from donnerap.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 863B93F66F; Fri, 8 Jul 2022 02:47:50 -0700 (PDT) Date: Fri, 8 Jul 2022 10:47:46 +0100 From: Andre Przywara To: Samuel Holland Cc: Jernej =?UTF-8?B?xaBrcmFiZWM=?= , Chen-Yu Tsai , Rob Herring , Krzysztof Kozlowski , Icenowy Zheng , linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v11 3/6] arm64: dts: allwinner: Add Allwinner H616 .dtsi file Message-ID: <20220708104746.6623e239@donnerap.cambridge.arm.com> In-Reply-To: <39537f95-2ed4-f526-5912-364c1c1ed512@sholland.org> References: <20220428230933.15262-1-andre.przywara@arm.com> <22699277.6Emhk5qWAg@kista> <20220704225534.3e1a901a@slackpad.lan> <5278570.Sb9uPGUboI@kista> <20220706141655.15d2dd0e@donnerap.cambridge.arm.com> <39537f95-2ed4-f526-5912-364c1c1ed512@sholland.org> Organization: ARM X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.32; aarch64-unknown-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, 7 Jul 2022 01:30:32 -0500 Samuel Holland wrote: Hi Samuel, > Hi Andre, Jernej, > > On 7/6/22 8:16 AM, Andre Przywara wrote: > > so after seemingly having finished writing this email, I realised that > > this won't really help, as I think this diverts the discussion. And the > > problem has been around for a while, and won't probably be solved easily > > or quickly. I think we agree to disagree here, or we should admit that > > there are different approaches ("bundled firmware" vs. "UEFI"), so in the > > interest of not blocking the H616 series: > > > > Shall I just keep the firmware node? This would work both ways, whereas > > dropping the node would impede the "bundled firmware" approach? > > Let me try to sum up the relevant portion of my thoughts (and save the rest for > elsewhere): > > The only reason to add the reserved-memory node is to support externally-loaded > DTBs. By adding the node, we are committing to support externally-loaded DTBs on > this SoC. > > Upgrading the kernel is not allowed to break boot. If we support > externally-loaded DTBs, that rule extends to DTBs shipped with the kernel. > > If we remove the reserved-memory node, the combination of old U-Boot + new > externally-loaded DTB will stop booting (the kernel version is irrelevant). > Therefore, if we add the node, we can never remove it, full stop. Well, this all depends on the initial commitment to support externally-loaded DTBs. I don't think we need to make this promise, I'd rather see this as a concession to people doing so *right now*, and for the sheer practicality of using this DT until we merge it into U-Boot. > I will (begrudgingly) accept that, as long as the node matches what TF-A > actually generates today. That means, please: > - Drop the label and update the node name I will drop the label. For the node name: the binding does not enforce it, but asks that "node names should reflect the purpose", so I went with "secmon", as used by other platforms. I will send a patch to TF-A to fix it there instead. If you disagree, feel free to fix this up before committing. > - Reduce the size to 256 KiB, matching (BL31_LIMIT - BL31_BASE) Verified in TF-A and changed. I also added a short comment explaining the situation. Feel free to amend this if needed. Many thanks for the discussion and for resolving this. I much appreciate your flexibility and pragmatism in this matter! Cheers, Andre