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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_MUTT 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 0751EC6778C for ; Tue, 3 Jul 2018 07:12:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B53B124DD8 for ; Tue, 3 Jul 2018 07:12:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="i8U8bl0s" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B53B124DD8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754226AbeGCHMf (ORCPT ); Tue, 3 Jul 2018 03:12:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:38178 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752839AbeGCHMe (ORCPT ); Tue, 3 Jul 2018 03:12:34 -0400 Received: from dragon (unknown [104.237.91.44]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3809224DCC; Tue, 3 Jul 2018 07:12:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1530601953; bh=ylrF7964J9Fk0nW7a0GxHSh/5AhJpRYjIDXweoA1g4o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=i8U8bl0sl97OSG7/KHRJMqa30I/txstM/9Jj5JogAEIuFdnSdaE+wwKaHRkqC3GhK MECT9JC6UuBXTjy4tf1ibhNKd12oIDQf+r7v9yFVhPUUgJ2Ee13deYG2C40VYaZj+S b/u/Ct4lPQ8bx5d5yVzugPA2nCSTv0/xNSJNqmOw= Date: Tue, 3 Jul 2018 15:12:16 +0800 From: Shawn Guo To: Viresh Kumar Cc: Lucas Stach , arm@kernel.org, Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Rob Herring , Mark Rutland , devicetree@vger.kernel.org, Vincent Guittot , Daniel Lezcano , linux-kernel@vger.kernel.org, chris.redpath@arm.com, ionela.voinescu@arm.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 15/15] arm: dts: imx: Add missing OPP properties for CPUs Message-ID: <20180703071215.GM4348@dragon> References: <264124e14b966a1bbc07c364fbd89fc55aa765e6.1527244201.git.viresh.kumar@linaro.org> <1527248760.3472.6.camel@pengutronix.de> <20180528110739.ewmhlf72sl7u5ju7@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180528110739.ewmhlf72sl7u5ju7@vireshk-i7> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 28, 2018 at 04:37:39PM +0530, Viresh Kumar wrote: > Hi Lucas, > > On 25-05-18, 13:46, Lucas Stach wrote: > > This is a lot of duplicate information for what is effectively a shared > > cluster wide thing. This does absolutely not _feel_ right. > > I cannot agree more :) > > > What problem are you solving here? Why do we need all this duplicate > > information? Why can't we fix it by falling back to looking at cpu0 if > > needed? > > Let me try explaining one of the problem scenarios to you as your > platform is a single cluster one. Make cpufreq driver as module, don't > insert it, hotplug out CPU0 and now insert the cpufreq driver. The > cpufreq core will try adding the cpufreq policy for CPU1 but wouldn't > find the required information in the DT node of CPU1 and so will fail > or behave incorrectly. > > We can't look at CPU0 as we don't know they are related at all. > Nothing tells that to us. The right solution to fix the duplication is > to move to OPP-v2 bindings, which allow us to create a single OPP > table node and refer to it from all the CPU nodes. Because in case of > imx platforms getting updated here, we use the old and some platforms > specific frequency tables, we have to duplicate it everywhere. > > But looking from DT otherwise, all the device should anyway have all > the information required right in their node. That can be simplified > with things like phandle to opp-v2 node, but still everything needs to > be there. We shouldn't really rely on other CPU nodes to make it work. > That would be an incomplete definition of the hardware IMHO. Lucas, Are you fine with the patch now considering the respond from Viresh? Shawn