e788892ba3
The design of the cpufreq governor API is not very straightforward, as struct cpufreq_governor provides only one callback to be invoked from different code paths for different purposes. The purpose it is invoked for is determined by its second "event" argument, causing it to act as a "callback multiplexer" of sorts. Unfortunately, that leads to extra complexity in governors, some of which implement the ->governor() callback as a switch statement that simply checks the event argument and invokes a separate function to handle that specific event. That extra complexity can be eliminated by replacing the all-purpose ->governor() callback with a family of callbacks to carry out specific governor operations: initialization and exit, start and stop and policy limits updates. That also turns out to reduce the code size too, so do it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
159 lines
4 KiB
C
159 lines
4 KiB
C
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/*
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* linux/drivers/cpufreq/cpufreq_userspace.c
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*
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* Copyright (C) 2001 Russell King
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* (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cpufreq.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
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static DEFINE_MUTEX(userspace_mutex);
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/**
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* cpufreq_set - set the CPU frequency
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* @policy: pointer to policy struct where freq is being set
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* @freq: target frequency in kHz
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*
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* Sets the CPU frequency to freq.
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*/
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static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
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{
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int ret = -EINVAL;
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unsigned int *setspeed = policy->governor_data;
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pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
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mutex_lock(&userspace_mutex);
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if (!per_cpu(cpu_is_managed, policy->cpu))
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goto err;
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*setspeed = freq;
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ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
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err:
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mutex_unlock(&userspace_mutex);
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return ret;
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}
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static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
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{
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return sprintf(buf, "%u\n", policy->cur);
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}
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static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
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{
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unsigned int *setspeed;
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setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL);
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if (!setspeed)
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return -ENOMEM;
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policy->governor_data = setspeed;
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return 0;
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}
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static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
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{
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mutex_lock(&userspace_mutex);
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kfree(policy->governor_data);
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policy->governor_data = NULL;
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mutex_unlock(&userspace_mutex);
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}
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static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
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{
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unsigned int *setspeed = policy->governor_data;
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BUG_ON(!policy->cur);
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pr_debug("started managing cpu %u\n", policy->cpu);
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mutex_lock(&userspace_mutex);
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per_cpu(cpu_is_managed, policy->cpu) = 1;
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*setspeed = policy->cur;
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mutex_unlock(&userspace_mutex);
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return 0;
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}
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static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
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{
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unsigned int *setspeed = policy->governor_data;
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pr_debug("managing cpu %u stopped\n", policy->cpu);
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mutex_lock(&userspace_mutex);
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per_cpu(cpu_is_managed, policy->cpu) = 0;
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*setspeed = 0;
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mutex_unlock(&userspace_mutex);
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}
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static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
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{
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unsigned int *setspeed = policy->governor_data;
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mutex_lock(&userspace_mutex);
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pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
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policy->cpu, policy->min, policy->max, policy->cur, *setspeed);
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if (policy->max < *setspeed)
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__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
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else if (policy->min > *setspeed)
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__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
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else
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__cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L);
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mutex_unlock(&userspace_mutex);
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}
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static struct cpufreq_governor cpufreq_gov_userspace = {
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.name = "userspace",
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.init = cpufreq_userspace_policy_init,
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.exit = cpufreq_userspace_policy_exit,
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.start = cpufreq_userspace_policy_start,
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.stop = cpufreq_userspace_policy_stop,
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.limits = cpufreq_userspace_policy_limits,
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.store_setspeed = cpufreq_set,
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.show_setspeed = show_speed,
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.owner = THIS_MODULE,
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};
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static int __init cpufreq_gov_userspace_init(void)
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{
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return cpufreq_register_governor(&cpufreq_gov_userspace);
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}
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static void __exit cpufreq_gov_userspace_exit(void)
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{
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cpufreq_unregister_governor(&cpufreq_gov_userspace);
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}
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MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
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"Russell King <rmk@arm.linux.org.uk>");
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MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
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MODULE_LICENSE("GPL");
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#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
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struct cpufreq_governor *cpufreq_default_governor(void)
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{
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return &cpufreq_gov_userspace;
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}
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fs_initcall(cpufreq_gov_userspace_init);
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#else
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module_init(cpufreq_gov_userspace_init);
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#endif
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module_exit(cpufreq_gov_userspace_exit);
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