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[209.132.180.67]) by mx.google.com with ESMTP id h56si814238eda.356.2019.11.13.00.41.04; Wed, 13 Nov 2019 00:41:04 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b="Tia/8E42"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727200AbfKMIlB (ORCPT + 26 others); Wed, 13 Nov 2019 03:41:01 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:36177 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725996AbfKMIk7 (ORCPT ); Wed, 13 Nov 2019 03:40:59 -0500 Received: by mail-wm1-f67.google.com with SMTP id c22so1016660wmd.1 for ; Wed, 13 Nov 2019 00:40:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Zp55sUzE/6lRk6a8ivnPTNcYxH9H+Lr3SiBACXS3e9U=; b=Tia/8E42XjbaQKn88fLe4L7drwoSdKwJdVXHfuantIzq2ohNNGYPjBoF6VaRmZla3U Ur4l6+lOwcfxvlzWDCqcrt/E93LHFOQKVdSvDElAiUsQbOlJtbWJSKiSiEsCN1asxt3d tUFT+sxPpQVKpBPgVeLSZ9P7D2HLLUJ66ZG45z5tA5KHo99a0iCP049Sr39z7haVCXg9 mCXwZezoZsXlOm6zq0iwZ/6n+lQxsETMwl/jFVKH8wDZefYkyW0Q7OaxdFjFe48QD2dY 0YL9MtZZX1+fzBsDFiwAHF6fayksdeR/ah5GCoc9PVWndfa0pXLqafipXyHOc0LUlVF9 9DWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Zp55sUzE/6lRk6a8ivnPTNcYxH9H+Lr3SiBACXS3e9U=; b=QeO6pT3i67JzjSlp03tQ+6UXOxnPAy6Sam7P3v4Y7m5fzSgo+cjCMRCQmMWvp1tPCi Un91g4NgMZCTPlyPuO6e40ObQoQ+KSHGYmatljFKc0nC520yRjmXtgO9ZBosyHmSj5XH r38g1vrf5T75fHFt6RFJ8lKaxd89s4bzt7d8I0JikQSNDtchQYlqAb872F/E4oWTIXIS wTe1psYBRiazPAApTCIpwzZ9la9WCEM97Gebj8Tk8aT1uMxHgr1/xBe2AOVbnrjM2wR6 1Xxq12I7msdEdrhPE3/ZtqbUqIEI5whOqRrnwbqxpkTTPosd6zVgs9rt9igokD4p5A+c SyPQ== X-Gm-Message-State: APjAAAWWEkeFdeqF45XUbm2orjDudeqB8N4rf8eAZJKUuJ6D7WCAM0xB f4Bfwcdg8R6OhNgwQtFrScdaoQ== X-Received: by 2002:a1c:99cb:: with SMTP id b194mr1722398wme.100.1573634456103; Wed, 13 Nov 2019 00:40:56 -0800 (PST) Received: from localhost.localdomain ([2a01:e34:ed2f:f020:8174:caa5:2144:f60]) by smtp.gmail.com with ESMTPSA id h205sm1667499wmf.35.2019.11.13.00.40.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Nov 2019 00:40:55 -0800 (PST) From: Daniel Lezcano To: rjw@rjwysocki.net, edubezval@gmail.com, rui.zhang@intel.com Cc: linux-pm@vger.kernel.org, viresh.kumar@linaro.org, amit.kucheria@linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/3] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver Date: Wed, 13 Nov 2019 09:40:42 +0100 Message-Id: <20191113084042.5707-3-daniel.lezcano@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191113084042.5707-1-daniel.lezcano@linaro.org> References: <20191113084042.5707-1-daniel.lezcano@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The cpu idle cooling device offers a new method to cool down a CPU by injecting idle cycles at runtime. It has some similarities with the intel power clamp driver but it is actually designed to be more generic and relying on the idle injection powercap framework. The idle injection cycle is fixed while the running cycle is variable. That allows to have control on the device reactivity for the user experience. An idle state powering down the CPU or the cluster will allow to drop the static leakage, thus restoring the heat capacity of the SoC. It can be set with a trip point between the hot and the critical points, giving the opportunity to prevent a hard reset of the system when the cpufreq cooling fails to cool down the CPU. With more sophisticated boards having a per core sensor, the idle cooling device allows to cool down a single core without throttling the compute capacity of several cpus belonging to the same clock line, so it could be used in collaboration with the cpufreq cooling device. Signed-off-by: Daniel Lezcano --- drivers/thermal/Kconfig | 7 + drivers/thermal/Makefile | 1 + drivers/thermal/cpuidle_cooling.c | 233 ++++++++++++++++++++++++++++++ include/linux/cpu_cooling.h | 22 +++ 4 files changed, 263 insertions(+) create mode 100644 drivers/thermal/cpuidle_cooling.c -- 2.17.1 diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 2b82c4861091..00d69906c508 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -168,6 +168,13 @@ config CPU_FREQ_THERMAL This will be useful for platforms using the generic thermal interface and not the ACPI interface. +config CPU_IDLE_THERMAL + bool "CPU idle cooling device" + depends on IDLE_INJECT + help + This implements the CPU cooling mechanism through + idle injection. This will throttle the CPU by injecting + idle cycle. endif config CLOCK_THERMAL diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index d3b01cc96981..9c8aa2d4bd28 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -20,6 +20,7 @@ thermal_sys-$(CONFIG_THERMAL_GOV_POWER_ALLOCATOR) += power_allocator.o # cpufreq cooling thermal_sys-$(CONFIG_CPU_FREQ_THERMAL) += cpu_cooling.o +thermal_sys-$(CONFIG_CPU_IDLE_THERMAL) += cpuidle_cooling.o # clock cooling thermal_sys-$(CONFIG_CLOCK_THERMAL) += clock_cooling.o diff --git a/drivers/thermal/cpuidle_cooling.c b/drivers/thermal/cpuidle_cooling.c new file mode 100644 index 000000000000..6e911fa87c47 --- /dev/null +++ b/drivers/thermal/cpuidle_cooling.c @@ -0,0 +1,233 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Linaro Limited. + * + * Author: Daniel Lezcano + * + */ +#include +#include +#include +#include +#include +#include +#include + +/** + * struct cpuidle_cooling_device - data for the idle cooling device + * @ii_dev: an atomic to keep track of the last task exiting the idle cycle + * @idle_duration_us: an integer defining the duration of the idle injection + * @state: an normalized integer giving the state of the cooling device + */ +struct cpuidle_cooling_device { + struct idle_inject_device *ii_dev; + unsigned int idle_duration_us; + unsigned long state; +}; + +static DEFINE_IDA(cpuidle_ida); + +/** + * cpuidle_cooling_runtime - Running time computation + * @idle_duration_us: the idle cooling device + * @state: a percentile based number + * + * The running duration is computed from the idle injection duration + * which is fixed. If we reach 100% of idle injection ratio, that + * means the running duration is zero. If we have a 50% ratio + * injection, that means we have equal duration for idle and for + * running duration. + * + * The formula is deduced as the following: + * + * running = idle x ((100 / ratio) - 1) + * + * For precision purpose for integer math, we use the following: + * + * running = (idle x 100) / ratio - idle + * + * For example, if we have an injected duration of 50%, then we end up + * with 10ms of idle injection and 10ms of running duration. + * + * Returns an unsigned int for an usec based runtime duration. + */ +static unsigned int cpuidle_cooling_runtime(unsigned int idle_duration_us, + unsigned long state) +{ + if (!state) + return 0; + + return ((idle_duration_us * 100) / state) - idle_duration_us; +} + +/** + * cpuidle_cooling_get_max_state - Get the maximum state + * @cdev : the thermal cooling device + * @state : a pointer to the state variable to be filled + * + * The function always gives 100 as the injection ratio is percentile + * based for consistency accros different platforms. + * + * The function can not fail, it always returns zero. + */ +static int cpuidle_cooling_get_max_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + /* + * Depending on the configuration or the hardware, the running + * cycle and the idle cycle could be different. We want unify + * that to an 0..100 interval, so the set state interface will + * be the same whatever the platform is. + * + * The state 100% will make the cluster 100% ... idle. A 0% + * injection ratio means no idle injection at all and 50% + * means for 10ms of idle injection, we have 10ms of running + * time. + */ + *state = 100; + + return 0; +} + +/** + * cpuidle_cooling_get_cur_state - Get the current cooling state + * @cdev: the thermal cooling device + * @state: a pointer to the state + * + * The function just copy the state value from the private thermal + * cooling device structure, the mapping is 1 <-> 1. + * + * The function can not fail, it always returns zero. + */ +static int cpuidle_cooling_get_cur_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct cpuidle_cooling_device *idle_cdev = cdev->devdata; + + *state = idle_cdev->state; + + return 0; +} + +/** + * cpuidle_cooling_set_cur_state - Set the current cooling state + * @cdev: the thermal cooling device + * @state: the target state + * + * The function checks first if we are initiating the mitigation which + * in turn wakes up all the idle injection tasks belonging to the idle + * cooling device. In any case, it updates the internal state for the + * cooling device. + * + * The function can not fail, it always returns zero. + */ +static int cpuidle_cooling_set_cur_state(struct thermal_cooling_device *cdev, + unsigned long state) +{ + struct cpuidle_cooling_device *idle_cdev = cdev->devdata; + struct idle_inject_device *ii_dev = idle_cdev->ii_dev; + unsigned long current_state = idle_cdev->state; + unsigned int runtime_us; + + idle_cdev->state = state; + + runtime_us = cpuidle_cooling_runtime(idle_cdev->idle_duration_us, + state); + + idle_inject_set_duration(ii_dev, runtime_us, + idle_cdev->idle_duration_us); + + if (current_state == 0 && state > 0) { + idle_inject_start(ii_dev); + } else if (current_state > 0 && !state) { + idle_inject_stop(ii_dev); + } + + return 0; +} + +/** + * cpuidle_cooling_ops - thermal cooling device ops + */ +static struct thermal_cooling_device_ops cpuidle_cooling_ops = { + .get_max_state = cpuidle_cooling_get_max_state, + .get_cur_state = cpuidle_cooling_get_cur_state, + .set_cur_state = cpuidle_cooling_set_cur_state, +}; + +/** + * cpuidle_of_cooling_register - Idle cooling device initialization function + * @drv: a cpuidle driver structure pointer + * + * This function is in charge of creating a cooling device per cpuidle + * driver and register it to thermal framework. + * + * Returns a valid pointer to a thermal cooling device, a PTR_ERR + * corresponding to the error detected in the underlying subsystems. + */ +struct thermal_cooling_device * +__init cpuidle_of_cooling_register(struct device_node *np, + struct cpuidle_driver *drv) +{ + struct idle_inject_device *ii_dev; + struct cpuidle_cooling_device *idle_cdev; + struct thermal_cooling_device *cdev; + char dev_name[THERMAL_NAME_LENGTH]; + int id, ret; + + ii_dev = idle_inject_register(drv->cpumask); + if (IS_ERR(ii_dev)) { + ret = PTR_ERR(ii_dev); + goto out; + } + + idle_cdev = kzalloc(sizeof(*idle_cdev), GFP_KERNEL); + if (!idle_cdev) { + ret = -ENOMEM; + goto out_unregister; + } + + id = ida_simple_get(&cpuidle_ida, 0, 0, GFP_KERNEL); + if (id < 0) { + ret = id; + goto out_kfree; + } + + idle_cdev->ii_dev = ii_dev; + idle_cdev->idle_duration_us = TICK_USEC; + + snprintf(dev_name, sizeof(dev_name), "thermal-idle-%d", id); + + cdev = thermal_of_cooling_device_register(np, dev_name, idle_cdev, + &cpuidle_cooling_ops); + if (IS_ERR(cdev)) { + ret = PTR_ERR(cdev); + goto out_id; + } + + return cdev; +out_id: + ida_simple_remove(&cpuidle_ida, id); +out_kfree: + kfree(idle_cdev); +out_unregister: + idle_inject_unregister(ii_dev); +out: + return ERR_PTR(ret); +} + +/** + * cpuidle_cooling_register - Idle cooling device initialization function + * @drv: a cpuidle driver structure pointer + * + * This function is in charge of creating a cooling device per cpuidle + * driver and register it to thermal framework. + * + * Returns a valid pointer to a thermal cooling device, a PTR_ERR + * corresponding to the error detected in the underlying subsystems. + */ +struct thermal_cooling_device * +__init cpuidle_cooling_register(struct cpuidle_driver *drv) +{ + return cpuidle_of_cooling_register(NULL, drv); +} diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h index 3cdd85f987d7..7873ac2f740b 100644 --- a/include/linux/cpu_cooling.h +++ b/include/linux/cpu_cooling.h @@ -60,4 +60,26 @@ of_cpufreq_cooling_register(struct cpufreq_policy *policy) } #endif /* CONFIG_CPU_FREQ_THERMAL */ +struct cpuidle_driver; + +#ifdef CONFIG_CPU_IDLE_THERMAL +extern struct thermal_cooling_device * +__init cpuidle_cooling_register(struct cpuidle_driver *drv); +extern struct thermal_cooling_device * +__init cpuidle_of_cooling_register(struct device_node *np, + struct cpuidle_driver *drv); +#else /* CONFIG_CPU_IDLE_THERMAL */ +static inline struct thermal_cooling_device * +__init cpuidle_cooling_register(struct cpuidle_driver *drv) +{ + return ERR_PTR(-EINVAL); +} +extern struct thermal_cooling_device * +__init cpuidle_of_cooling_register(struct device_node *np, + struct cpuidle_driver *drv) +{ + return ERR_PTR(-EINVAL); +} +#endif /* CONFIG_CPU_IDLE_THERMAL */ + #endif /* __CPU_COOLING_H__ */