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,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 22035C282C8 for ; Mon, 28 Jan 2019 19:02:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6E4921738 for ; Mon, 28 Jan 2019 19:02:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="iuNWNOiK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727521AbfA1TCz (ORCPT ); Mon, 28 Jan 2019 14:02:55 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:40713 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727259AbfA1TCy (ORCPT ); Mon, 28 Jan 2019 14:02:54 -0500 Received: by mail-pg1-f193.google.com with SMTP id z10so7602396pgp.7 for ; Mon, 28 Jan 2019 11:02:54 -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=0UeBKRmlOKYymh/cEL0B20ZM7YaatafhkCzpbkFAoFQ=; b=iuNWNOiKGFnZUjv1xiem14aYA7nKWnY93Ou1LFrVt4MTk/kdWOoIVqcDPm8U52wvzN lRif1wWZswl3O0PdY25yY9RIV3E2HJkbTHiH5DxhrOVu5KFj8IEVTjn67gmz+SrpZltq iG/3LTh7CFVpJojBl7YjPP+BnfFQvL00mgBGU= 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=0UeBKRmlOKYymh/cEL0B20ZM7YaatafhkCzpbkFAoFQ=; b=noAt9WhI4KIp21cHYC7RegZ9ZbYEbN509fwPFvvPCAaHlHEchUpWPPy5ZfHjSPgq1E f+AqeNb8MzNhEp+yftWylLvnOu/e10crUrgcWzaSiZADr4XOGU4piB/LR4ZjSbBFXuIZ aBEN6UBeSMyR2k3/RV4pddeLbNT48mv506AwLBMgQnA6YEZ1S/xfuncBhGgrq4qpwIVI uVFQMwyLsHtMx5DqcZbPHCStE2YdUNMHV5RTibp+3V0uxBDBvULGNQMGZlkBU8h+UN8t m8DvQ5U69fQNxuUFpeKqJaK7nixNVr6phnWlQ5YhL+zaPbrL/ePOY0iFvx/rfQXWCivC ZliA== X-Gm-Message-State: AJcUukffGO0cdBtNGD2+d7LaaRONA99hDhJ87PNR9hJathOHmoZLMT6U 51GxmCWTDNFDP8hYbxwLSZ/lSg== X-Google-Smtp-Source: ALg8bN7v9iOVPw+QC2CG2f/8uJmADLIoAiqORJU5jr/Wi2SXuCAuj01Y5sUUNjdX7MQW6Ap0LVDZmA== X-Received: by 2002:a63:cc12:: with SMTP id x18mr20800227pgf.33.1548702173594; Mon, 28 Jan 2019 11:02:53 -0800 (PST) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id o1sm61659860pgn.63.2019.01.28.11.02.52 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 28 Jan 2019 11:02:52 -0800 (PST) Date: Mon, 28 Jan 2019 11:02:51 -0800 From: Matthias Kaehlcke To: Quentin Perret Cc: rjw@rjwysocki.net, viresh.kumar@linaro.org, sudeep.holla@arm.com, liviu.dudau@arm.com, lorenzo.pieralisi@arm.com, robh+dt@kernel.org, mark.rutland@arm.com, nm@ti.com, sboyd@kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, dietmar.eggemann@arm.com Subject: Re: [PATCH 1/7] PM / OPP: Introduce a power estimation helper Message-ID: <20190128190251.GH81583@google.com> References: <20190128165522.31749-1-quentin.perret@arm.com> <20190128165522.31749-2-quentin.perret@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190128165522.31749-2-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 rHi Quentin, On Mon, Jan 28, 2019 at 04:55:16PM +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 > --- > drivers/opp/of.c | 60 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/pm_opp.h | 5 ++++ > 2 files changed, 65 insertions(+) > > diff --git a/drivers/opp/of.c b/drivers/opp/of.c > index 06f0f632ec47..7572a2eb2fd4 100644 > --- a/drivers/opp/of.c > +++ b/drivers/opp/of.c > @@ -1047,3 +1047,63 @@ 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); > + > +/** > + * of_dev_pm_opp_get_cpu_power() - Estimates the power of a CPU > + * @mW: pointer to the power estimate in milli-watts > + * @KHz: pointer to the OPP's frequency, in kilo-hertz nit: should be kHz > + * @cpu: CPU for which power needs to be estimated > + * > + * Computes the power estimated by @CPU at the first OPP above @KHz (ceil), > + * and updates @KHz and @mW accordingly. > + * > + * The power is estimated as P = C * V^2 * f, with C the CPU's capacitance > + * (read from the 'dynamic-power-coefficient' devicetree binding) and V and f > + * respectively the voltage and frequency of the OPP. > + * > + * Return: -ENODEV if the CPU device cannot be found, -EINVAL if the power > + * calculation failed because of missing parameters, 0 otherwise. > + */ > +int of_dev_pm_opp_get_cpu_power(unsigned long *mW, unsigned long *KHz, int cpu) I think it is more common to put the input parameters first, then the output ones, i.e. cpu, kHz, mW. > +{ > + unsigned long mV, Hz, MHz; > + struct device *cpu_dev; > + struct dev_pm_opp *opp; > + struct device_node *np; > + 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; > + > + MHz = Hz / 1000000; > + tmp = (u64)cap * mV * mV * MHz; > + do_div(tmp, 1000000000); > + > + *mW = (unsigned long)tmp; > + *KHz = Hz / 1000; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(of_dev_pm_opp_get_cpu_power); > diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h > index 0a2a88e5a383..fedde14f5187 100644 > --- a/include/linux/pm_opp.h > +++ b/include/linux/pm_opp.h > @@ -322,6 +322,7 @@ 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); > +int of_dev_pm_opp_get_cpu_power(unsigned long *mW, unsigned long *KHz, int cpu); > #else > static inline int dev_pm_opp_of_add_table(struct device *dev) > { > @@ -364,6 +365,10 @@ static inline int of_get_required_opp_performance_state(struct device_node *np, > { > return -ENOTSUPP; > } > +static inline int of_dev_pm_opp_get_cpu_power(unsigned long *mW, unsigned long *KHz, int cpu) > +{ > + return -ENOTSUPP; > +} > #endif > > #endif /* __LINUX_OPP_H__ */ Besides the nits above: Reviewed-by: Matthias Kaehlcke Tested-by: Matthias Kaehlcke