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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 207C2C2D0DB for ; Mon, 20 Jan 2020 18:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF9E922525 for ; Mon, 20 Jan 2020 18:27:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727121AbgATS1g (ORCPT ); Mon, 20 Jan 2020 13:27:36 -0500 Received: from foss.arm.com ([217.140.110.172]:35484 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726642AbgATS1f (ORCPT ); Mon, 20 Jan 2020 13:27:35 -0500 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 A249731B; Mon, 20 Jan 2020 10:27:34 -0800 (PST) Received: from [192.168.0.7] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2843F3F68E; Mon, 20 Jan 2020 10:27:28 -0800 (PST) Subject: Re: [PATCH 1/4] PM / EM: and devices to Energy Model To: Quentin Perret , Lukasz Luba Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-imx@nxp.com, Morten.Rasmussen@arm.com, Chris.Redpath@arm.com, ionela.voinescu@arm.com, javi.merino@arm.com, cw00.choi@samsung.com, b.zolnierkie@samsung.com, rjw@rjwysocki.net, sudeep.holla@arm.com, viresh.kumar@linaro.org, nm@ti.com, sboyd@kernel.org, rui.zhang@intel.com, amit.kucheria@verdurent.com, daniel.lezcano@linaro.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, kernel@pengutronix.de, khilman@kernel.org, agross@kernel.org, bjorn.andersson@linaro.org, robh@kernel.org, matthias.bgg@gmail.com, steven.price@arm.com, tomeu.vizoso@collabora.com, alyssa.rosenzweig@collabora.com, airlied@linux.ie, daniel@ffwll.ch, kernel-team@android.com References: <20200116152032.11301-1-lukasz.luba@arm.com> <20200116152032.11301-2-lukasz.luba@arm.com> <20200117105437.GA211774@google.com> <40587d98-0e8d-cbac-dbf5-d26501d47a8c@arm.com> <20200120150918.GA164543@google.com> From: Dietmar Eggemann Message-ID: <8332c4ac-2a7d-1e2d-76e9-7c979a666257@arm.com> Date: Mon, 20 Jan 2020 19:27:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200120150918.GA164543@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/01/2020 16:09, Quentin Perret wrote: > Hey Lukasz, > > On Monday 20 Jan 2020 at 14:52:07 (+0000), Lukasz Luba wrote: >> On 1/17/20 10:54 AM, Quentin Perret wrote: >>> Suggested alternative: have two registration functions like so: >>> >>> int em_register_dev_pd(struct device *dev, unsigned int nr_states, >>> struct em_data_callback *cb); >>> int em_register_cpu_pd(cpumask_t *span, unsigned int nr_states, >>> struct em_data_callback *cb); >> >> Interesting, in the internal review Dietmar asked me to remove these two >> functions. I had the same idea, which would simplify a bit the >> registration and it does not need to check the dev->bus if it is CPU. >> >> Unfortunately, we would need also two function in drivers/opp/of.c: >> dev_pm_opp_of_register_cpu_em(policy->cpus); >> and >> dev_pm_opp_of_register_dev_em(dev); >> >> Thus, I have created only one registration function, which you can see >> in this patch set. > > Right, I can see how having a unified API would be appealing, but the > OPP dependency is a nono, so we'll need to work around one way or > another. > > FWIW, I don't think having separate APIs for CPUs and other devices is > that bad given that we already have entirely different frameworks to > drive their respective frequencies. And the _cpu variants are basically > just wrappers around the _dev ones, so not too bad either IMO :). It's true that we need the policy->cpus cpumask only for cpu devices and we have it available when we call em_register_perf_domain() [scmi-cpufreq.c driver] or the OPP wrapper dev_pm_opp_of_register_em() [e.g. cpufreq-dt.c driver]. And we shouldn't make EM code dependent on OPP. But can't we add 'struct cpumask *mask' as an additional argument to both which can be set to NULL for (devfreq) devices? We can check in em_register_perf_domain() that we got a valid cpumask for a cpu device and ignore it for (devfreq) devices.