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 1862FC33CAA for ; Mon, 20 Jan 2020 18:38:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F01C52253D for ; Mon, 20 Jan 2020 18:38:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726843AbgATSiz (ORCPT ); Mon, 20 Jan 2020 13:38:55 -0500 Received: from foss.arm.com ([217.140.110.172]:35624 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726112AbgATSiz (ORCPT ); Mon, 20 Jan 2020 13:38:55 -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 D770E31B; Mon, 20 Jan 2020 10:38:53 -0800 (PST) Received: from [10.37.12.169] (unknown [10.37.12.169]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B943B3F68E; Mon, 20 Jan 2020 10:38:43 -0800 (PST) Subject: Re: [PATCH 1/4] PM / EM: and devices to Energy Model To: Dietmar Eggemann , Quentin Perret 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> <8332c4ac-2a7d-1e2d-76e9-7c979a666257@arm.com> From: Lukasz Luba Message-ID: Date: Mon, 20 Jan 2020 18:38:41 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <8332c4ac-2a7d-1e2d-76e9-7c979a666257@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed 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 1/20/20 6:27 PM, Dietmar Eggemann wrote: > 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. > I think we could avoid this additional argument 'cpumask'. I have checked the cpufreq_cpu_get function, which should do be good for this: ---------->8------------------------- static int _get_sharing_cpus(struct device *cpu_dev, struct cpumask *span) { struct cpufreq_policy *policy; policy = cpufreq_cpu_get(cpu_dev->id); if (policy) { cpumask_copy(span, policy->cpus); cpufreq_cpu_put(policy); return 0; } else { return -EINVAL; } } --------------------------8<------------------------------- It would be a replacement for: ret = dev_pm_opp_get_sharing_cpus(dev, span); Regards, Lukasz