// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2019 Linaro Limited. * * Author: Daniel Lezcano <[email protected]> * */ #define pr_fmt(fmt) … #include <linux/cpu.h> #include <linux/cpu_cooling.h> #include <linux/cpuidle.h> #include <linux/device.h> #include <linux/err.h> #include <linux/idle_inject.h> #include <linux/of.h> #include <linux/slab.h> #include <linux/thermal.h> /** * 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 * @state: a normalized integer giving the state of the cooling device */ struct cpuidle_cooling_device { … }; /** * cpuidle_cooling_runtime - Running time computation * @idle_duration_us: CPU idle time to inject in microseconds * @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 follows: * * 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. * * Return: An unsigned int for a usec based runtime duration. */ static unsigned int cpuidle_cooling_runtime(unsigned int idle_duration_us, unsigned long state) { … } /** * 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 returns 100 as the injection ratio. It is * percentile based for consistency across different platforms. * * Return: The function can not fail, it is always zero */ static int cpuidle_cooling_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { … } /** * cpuidle_cooling_get_cur_state - Get the current cooling state * @cdev: the thermal cooling device * @state: a pointer to the state * * The function just copies the state value from the private thermal * cooling device structure, the mapping is 1 <-> 1. * * Return: The function can not fail, it is always zero */ static int cpuidle_cooling_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) { … } /** * 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. * * Return: The function can not fail, it is always zero */ static int cpuidle_cooling_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { … } /* * cpuidle_cooling_ops - thermal cooling device ops */ static struct thermal_cooling_device_ops cpuidle_cooling_ops = …; /** * __cpuidle_cooling_register: register the cooling device * @drv: a cpuidle driver structure pointer * @np: a device node structure pointer used for the thermal binding * * This function is in charge of allocating the cpuidle cooling device * structure, the idle injection, initialize them and register the * cooling device to the thermal framework. * * Return: zero on success, a negative value returned by one of the * underlying subsystem in case of error */ static int __cpuidle_cooling_register(struct device_node *np, struct cpuidle_driver *drv) { … } /** * 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 the thermal framework. */ void cpuidle_cooling_register(struct cpuidle_driver *drv) { … }
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