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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 BFFAAC282C4 for ; Mon, 4 Feb 2019 18:03:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 873BB2175B for ; Mon, 4 Feb 2019 18:03:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="F/MuCsy0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729144AbfBDSDG (ORCPT ); Mon, 4 Feb 2019 13:03:06 -0500 Received: from mail-pl1-f196.google.com ([209.85.214.196]:40310 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729090AbfBDSDG (ORCPT ); Mon, 4 Feb 2019 13:03:06 -0500 Received: by mail-pl1-f196.google.com with SMTP id u18so271601plq.7 for ; Mon, 04 Feb 2019 10:03:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=pa+Vc7SY0LoQnG2/tXw6TGPTX86UGYys3lkAel8SuIw=; b=F/MuCsy04csfh0tIaC4dehv6E2hS3A6dyoUz+BDIet6FsoHnz/ZVJfYL56jG0munBE 4yDLI2XKbL03jrxzf9D/SWU9YYTxS1taQFIFyXdpXQSMhaNeoFnuLIVXRyLtms+kxhZk qaOC/b3Tbd53oYDt4b58JtHSAyDRDvzcwdLuo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=pa+Vc7SY0LoQnG2/tXw6TGPTX86UGYys3lkAel8SuIw=; b=untxXzBwN2NCO6+ZVTNLqO3X4KGj0m01CIZkOp1vi2O9Js6Bgisl9li3WtLFAkktzi 2F1svEwWy3Avbrwuy3dPKVvjnBwaWWHMdtrSmE4+LVzSDhvV3HgoOVwjwlYg/5x7grpz JefZ/uQfL4A+nd4+2lZEEuaySGT1beGOThvNhuVovswsyUvYAjtyMB/BDr9Cz97tIrZK Vi2BSJebz5Dz6AytmBtQetBi1dv9+3hyhVAcgeEDZ001bhim8g8NgTGGeh+H5WTOlsAS AWZpMK+vFNX8rrhJN0H37LHbkBcAbRS49ytBCjhhpdVQdKsAwYrrDfxUQEdtbvuYTrNT U8xQ== X-Gm-Message-State: AHQUAuZS9kGGHlCMKRxgHd+cUc5wwn08ARPdBLTQNWzLssIS9fW306MV moSDB20maslkJM3UaZ2dWnrKLbHoBiY= X-Google-Smtp-Source: AHgI3Ia2MdcklPsX7BhkL3jYEmVjX2yyZgFn3/yfyAoM614ZdmlSLjM/F1zdgeg+EbFgvgjrjNZmIg== X-Received: by 2002:a17:902:50e3:: with SMTP id c32mr632085plj.318.1549303384891; Mon, 04 Feb 2019 10:03:04 -0800 (PST) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id d129sm966231pfc.31.2019.02.04.10.03.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 04 Feb 2019 10:03:04 -0800 (PST) Date: Mon, 4 Feb 2019 10:03:03 -0800 From: Matthias Kaehlcke To: Quentin Perret Cc: viresh.kumar@linaro.org, sudeep.holla@arm.com, rjw@rjwysocki.net, nm@ti.com, sboyd@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dietmar.eggemann@arm.com Subject: Re: [PATCH v4 1/5] PM / OPP: Introduce a power estimation helper Message-ID: <20190204180303.GD117604@google.com> References: <20190204110952.16025-1-quentin.perret@arm.com> <20190204110952.16025-2-quentin.perret@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190204110952.16025-2-quentin.perret@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 04, 2019 at 11:09:48AM +0000, Quentin Perret wrote: > The Energy Model (EM) framework provides an API to let drivers register > the active power of CPUs. The drivers are expected to provide a callback > method which estimates the power consumed by a CPU at each available > performance levels. How exactly this should be implemented, however, > depends on the platform. > > On some systems, PM_OPP knows the voltage and frequency at which CPUs > can run. When coupled with the CPU 'capacitance' (as provided by the > 'dynamic-power-coefficient' devicetree binding), it is possible to > estimate the dynamic power consumption of a CPU as P = C * V^2 * f, with > C its capacitance and V and f respectively the voltage and frequency of > the OPP. The Intelligent Power Allocator (IPA) thermal governor already > implements that estimation method, in the thermal framework. > > However, this power estimation method can be applied to any platform > where all the parameters are known (C, V and f), and not only those > suffering thermal issues. As such, the code implementing this feature > can be re-used to also populate the EM framework now used by EAS. > > As a first step, introduce in PM_OPP a helper function which CPUFreq > drivers can use to register into the EM framework. This duplicates the > power estimation done in IPA until it can be migrated to using the EM > framework. This will be done later, once the EM framework has support > for at least all platforms currently supported by IPA. > > Signed-off-by: Quentin Perret > Tested-by: Matthias Kaehlcke > --- > drivers/opp/of.c | 99 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/pm_opp.h | 6 +++ > 2 files changed, 105 insertions(+) > > diff --git a/drivers/opp/of.c b/drivers/opp/of.c > index 06f0f632ec47..cd58959e5158 100644 > --- a/drivers/opp/of.c > +++ b/drivers/opp/of.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > #include "opp.h" > > @@ -1047,3 +1048,101 @@ struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp) > return of_node_get(opp->np); > } > EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node); > + > +/* > + * Callback function provided to the Energy Model framework upon registration. > + * This computes the power estimated by @CPU at @kHz if it is the frequency > + * of an existing OPP, or at the frequency of the first OPP above @kHz otherwise > + * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled > + * frequency and @mW to the associated power. The power is estimated as > + * P = C * V^2 * f with C being the CPU's capacitance and V and f respectively > + * the voltage and frequency of the OPP. > + * > + * Returns -ENODEV if the CPU device cannot be found, -EINVAL if the power > + * calculation failed because of missing parameters, 0 otherwise. > + */ > +static int __maybe_unused _get_cpu_power(unsigned long *mW, unsigned long *kHz, > + int cpu) > +{ > + struct device *cpu_dev; > + struct dev_pm_opp *opp; > + struct device_node *np; > + unsigned long mV, Hz; > + u32 cap; > + u64 tmp; > + int ret; > + > + cpu_dev = get_cpu_device(cpu); > + if (!cpu_dev) > + return -ENODEV; > + > + np = of_node_get(cpu_dev->of_node); > + if (!np) > + return -EINVAL; > + > + ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap); > + of_node_put(np); > + if (ret) > + return -EINVAL; > + > + Hz = *kHz * 1000; > + opp = dev_pm_opp_find_freq_ceil(cpu_dev, &Hz); > + if (IS_ERR(opp)) > + return -EINVAL; > + > + mV = dev_pm_opp_get_voltage(opp) / 1000; > + dev_pm_opp_put(opp); > + if (!mV) > + return -EINVAL; > + > + tmp = (u64)cap * mV * mV * (Hz / 1000000); > + do_div(tmp, 1000000000); > + > + *mW = (unsigned long)tmp; > + *kHz = Hz / 1000; > + > + return 0; > +} > + > +/** > + * dev_pm_opp_of_register_em() - Attempt to register an Energy Model > + * @cpus : CPUs for which an Energy Model has to be registered > + * > + * This checks whether the "dynamic-power-coefficient" devicetree property has > + * been specified, and tries to register an Energy Model with it if it has. > + */ > +void dev_pm_opp_of_register_em(struct cpumask *cpus) > +{ > + struct em_data_callback em_cb = EM_DATA_CB(_get_cpu_power); > + int ret, nr_opp, cpu = cpumask_first(cpus); > + struct device *cpu_dev; > + struct device_node *np; > + u32 cap; > + > + cpu_dev = get_cpu_device(cpu); > + if (!cpu_dev) > + return; > + > + nr_opp = dev_pm_opp_get_opp_count(cpu_dev); > + if (nr_opp <= 0) > + return; > + > + np = of_node_get(cpu_dev->of_node); > + if (!np) > + return; > + > + /* > + * Register an EM only if the 'dynamic-power-coefficient' property is > + * set in devicetree. It is assumed the voltage values are known if that > + * property is set since it is useless otherwise. If voltages are not > + * known, just let the EM registration fail with an error to alert the > + * user about the inconsistent configuration. > + */ > + ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap); > + of_node_put(np); > + if (ret || !cap) > + return; > + > + em_register_perf_domain(cpus, nr_opp, &em_cb); > +} > +EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em); > diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h > index b895f4e79868..c9c76310865a 100644 > --- a/include/linux/pm_opp.h > +++ b/include/linux/pm_opp.h > @@ -327,6 +327,7 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpuma > struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev); > struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp); > int of_get_required_opp_performance_state(struct device_node *np, int index); > +void dev_pm_opp_of_register_em(struct cpumask *cpus); > #else > static inline int dev_pm_opp_of_add_table(struct device *dev) > { > @@ -365,6 +366,11 @@ static inline struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp) > { > return NULL; > } > + > +static inline void dev_pm_opp_of_register_em(struct cpumask *cpus) > +{ > +} > + > static inline int of_get_required_opp_performance_state(struct device_node *np, int index) > { > return -ENOTSUPP; There is the option to remove the OPP check from the cpufreq drivers and instead return an error from dev_pm_opp_of_register_em(), but with the more complex error handling it might be more hassle than it's worth. Reviewed-by: Matthias Kaehlcke