From patchwork Mon Jan 28 16:55:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Perret X-Patchwork-Id: 10784069 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 381CC922 for ; Mon, 28 Jan 2019 16:56:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 255652B8E0 for ; Mon, 28 Jan 2019 16:56:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 18A122B921; Mon, 28 Jan 2019 16:56:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 883D62B8E0 for ; Mon, 28 Jan 2019 16:56:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388371AbfA1Qzg (ORCPT ); Mon, 28 Jan 2019 11:55:36 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:49816 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388745AbfA1Qzd (ORCPT ); Mon, 28 Jan 2019 11:55:33 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5B1B815AD; Mon, 28 Jan 2019 08:55:33 -0800 (PST) Received: from queper01-lin.cambridge.arm.com (queper01-lin.cambridge.arm.com [10.1.195.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AD37B3F59C; Mon, 28 Jan 2019 08:55:30 -0800 (PST) From: Quentin Perret To: 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 Cc: linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, dietmar.eggemann@arm.com, mka@chromium.org, quentin.perret@arm.com Subject: [PATCH 1/7] PM / OPP: Introduce a power estimation helper Date: Mon, 28 Jan 2019 16:55:16 +0000 Message-Id: <20190128165522.31749-2-quentin.perret@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190128165522.31749-1-quentin.perret@arm.com> References: <20190128165522.31749-1-quentin.perret@arm.com> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 Reviewed-by: Matthias Kaehlcke Tested-by: Matthias Kaehlcke --- 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 + * @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) +{ + 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__ */