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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 4AF2DC282CC for ; Mon, 4 Feb 2019 11:10:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B033207E0 for ; Mon, 4 Feb 2019 11:10:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731268AbfBDLKa (ORCPT ); Mon, 4 Feb 2019 06:10:30 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:53960 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730775AbfBDLKC (ORCPT ); Mon, 4 Feb 2019 06:10:02 -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 4881415BE; Mon, 4 Feb 2019 03:10:01 -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 57DB03F675; Mon, 4 Feb 2019 03:09:59 -0800 (PST) From: Quentin Perret To: viresh.kumar@linaro.org, sudeep.holla@arm.com, rjw@rjwysocki.net, nm@ti.com, sboyd@kernel.org, mka@chromium.org Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dietmar.eggemann@arm.com, quentin.perret@arm.com Subject: [PATCH v4 1/5] PM / OPP: Introduce a power estimation helper Date: Mon, 4 Feb 2019 11:09:48 +0000 Message-Id: <20190204110952.16025-2-quentin.perret@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190204110952.16025-1-quentin.perret@arm.com> References: <20190204110952.16025-1-quentin.perret@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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; -- 2.20.1