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 541ACC433FE for ; Wed, 4 May 2022 22:33:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376779AbiEDWgp (ORCPT ); Wed, 4 May 2022 18:36:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235969AbiEDWgo (ORCPT ); Wed, 4 May 2022 18:36:44 -0400 Received: from mail-oi1-f179.google.com (mail-oi1-f179.google.com [209.85.167.179]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14A1943AF0; Wed, 4 May 2022 15:33:08 -0700 (PDT) Received: by mail-oi1-f179.google.com with SMTP id v66so2656541oib.3; Wed, 04 May 2022 15:33:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=KCLvskmQfHSLQoHJU153xgGm9qqnQf982R9B7b1MPpE=; b=iVxMS5+PMEbzM5EVKMhnSr6iVhmsQ9GDOwkLEf6PTSQE8WPa0d/4aET7+2ALsneQaZ Z5GW1uAwOFqljJ6W9UjbfQ5wO85nKtXlIxifKV/Ry7r0IY8kY1IYVbpo0j1B9keWQRBj CL22J2F/GHpRLIXpIKFPsYLjL4XlvwiYPq7SudDl7ZjvvAlY7y9HfK/TrRJIAEoCkAfT eDLzA3WXQTq9qvPFLrDOEr5gFolx1YoILPxVODUhPxMWxZCRAGs9y26+Z9jcBZNo3ogY 3DxTpZzuhNu1YnteY/paDV1aB1uUB1cHsBW2Of2JzPB+eK6YSZx7vWf+W3DBuQyzvYh/ zH3w== X-Gm-Message-State: AOAM530rlIxY3cSkbr9aLfvSELp9r85FxKkuiOkYHq4/qhMKzwxRFJSa bhjBIav0NNaw/dIULq8bRDWDihS9Ww== X-Google-Smtp-Source: ABdhPJzX75QPJo7huwKRdcTHPA1Mya1GI5o9IG77cAhJ532Ijr4YyWgeYwfcIaOYHc1D9ijJqxufAg== X-Received: by 2002:a54:4398:0:b0:325:6312:1520 with SMTP id u24-20020a544398000000b0032563121520mr903959oiv.53.1651703587285; Wed, 04 May 2022 15:33:07 -0700 (PDT) Received: from robh.at.kernel.org (66-90-144-107.dyn.grandenetworks.net. [66.90.144.107]) by smtp.gmail.com with ESMTPSA id b20-20020a4ae214000000b0035eb4e5a6c1sm62021oot.23.2022.05.04.15.33.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 May 2022 15:33:06 -0700 (PDT) Received: (nullmailer pid 2345673 invoked by uid 1000); Wed, 04 May 2022 22:33:06 -0000 Date: Wed, 4 May 2022 17:33:05 -0500 From: Rob Herring To: Mark Rutland , Phil Edworthy Cc: Krzysztof Kozlowski , Geert Uytterhoeven , Biju Das , Daniel Lezcano , Thomas Gleixner , Marc Zyngier , devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH v3 04/12] dt-bindings: timer: arm,arch_timer: Add optional clock and reset Message-ID: References: <20220503115557.53370-1-phil.edworthy@renesas.com> <20220503115557.53370-5-phil.edworthy@renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, May 03, 2022 at 02:11:59PM +0100, Mark Rutland wrote: > Hi Phil, > > This is the only patch from this series that I've received, and judging > by the CC list this hasn't gone to either LKML or LAKML, so I'm missing > the surrounding context for this. > > Looking on lore, this is part of: > > https://lore.kernel.org/linux-devicetree/20220503115557.53370-1-phil.edworthy@renesas.com/T/#t > > ... which is adding support for an arm64 SoC. > > On Tue, May 03, 2022 at 12:55:49PM +0100, Phil Edworthy wrote: > > Some SoCs use a gated clock for the timer and the means to reset the timer. > > Hence add these as optional. > > The clock feeding the architected timer is supposed to be in an > always-on clock domain, and is supopsed to be enabled before running any > Normal World software. > > The arm64 kernel *requires* that this is enabled prior to entry. If the > kernel ever has to touch either the clock or reset, then there are > phases where the counter will not function correctly, which is simply > broken. > > Given that, I do not think this should be in the DT, and instead the > clock should be marked as critical in the provider node (and the reset > should never be touched). That is not yet an accepted DT property, but is currently on the list for review[1]. If that's something people need, chime in. More than 1 person needing something is always better. Rob [1] https://lore.kernel.org/all/20220428110107.149524-1-marex@denx.de/