/* *  linux/drivers/cpufreq/cpufreq_userspace.c * *  Copyright (C)  2001 Russell King *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #include <linux/kernel.h>#include <linux/module.h>#include <linux/smp.h>#include <linux/init.h>#include <linux/spinlock.h>#include <linux/interrupt.h>#include <linux/cpufreq.h>#include <linux/cpu.h>#include <linux/types.h>#include <linux/fs.h>#include <linux/sysfs.h>#include <linux/mutex.h> /** * A few values needed by the userspace governor */static DEFINE_PER_CPU(unsigned int, cpu_max_freq);static DEFINE_PER_CPU(unsigned int, cpu_min_freq);static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by							userspace */static DEFINE_PER_CPU(unsigned int, cpu_is_managed); static DEFINE_MUTEX(userspace_mutex);static int cpus_using_userspace_governor; /* keep track of frequency transitions */static intuserspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,	void *data){	struct cpufreq_freqs *freq = data; 	if (!per_cpu(cpu_is_managed, freq->cpu))		return 0; 	if (val == CPUFREQ_POSTCHANGE) {		pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n",				freq->cpu, freq->new);		per_cpu(cpu_cur_freq, freq->cpu) = freq->new;	} 	return 0;} static struct notifier_block userspace_cpufreq_notifier_block = {	.notifier_call  = userspace_cpufreq_notifier};  /** * cpufreq_set - set the CPU frequency * @policy: pointer to policy struct where freq is being set * @freq: target frequency in kHz * * Sets the CPU frequency to freq. */static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq){	int ret = -EINVAL; 	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); 	mutex_lock(&userspace_mutex);	if (!per_cpu(cpu_is_managed, policy->cpu))		goto err; 	per_cpu(cpu_set_freq, policy->cpu) = freq; 	if (freq < per_cpu(cpu_min_freq, policy->cpu))		freq = per_cpu(cpu_min_freq, policy->cpu);	if (freq > per_cpu(cpu_max_freq, policy->cpu))		freq = per_cpu(cpu_max_freq, policy->cpu); 	/*	 * We're safe from concurrent calls to ->target() here	 * as we hold the userspace_mutex lock. If we were calling	 * cpufreq_driver_target, a deadlock situation might occur:	 * A: cpufreq_set (lock userspace_mutex) ->	 *      cpufreq_driver_target(lock policy->lock)	 * B: cpufreq_set_policy(lock policy->lock) ->	 *      __cpufreq_governor ->	 *         cpufreq_governor_userspace (lock userspace_mutex)	 */	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);  err:	mutex_unlock(&userspace_mutex);	return ret;}  static ssize_t show_speed(struct cpufreq_policy *policy, char *buf){	return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu));} static int cpufreq_governor_userspace(struct cpufreq_policy *policy,				   unsigned int event){	unsigned int cpu = policy->cpu;	int rc = 0; 	switch (event) {	case CPUFREQ_GOV_START:		if (!cpu_online(cpu))			return -EINVAL;		BUG_ON(!policy->cur);		mutex_lock(&userspace_mutex); 		if (cpus_using_userspace_governor == 0) {			cpufreq_register_notifier(					&userspace_cpufreq_notifier_block,					CPUFREQ_TRANSITION_NOTIFIER);		}		cpus_using_userspace_governor++; 		per_cpu(cpu_is_managed, cpu) = 1;		per_cpu(cpu_min_freq, cpu) = policy->min;		per_cpu(cpu_max_freq, cpu) = policy->max;		per_cpu(cpu_cur_freq, cpu) = policy->cur;		per_cpu(cpu_set_freq, cpu) = policy->cur;		pr_debug("managing cpu %u started "			"(%u - %u kHz, currently %u kHz)\n",				cpu,				per_cpu(cpu_min_freq, cpu),				per_cpu(cpu_max_freq, cpu),				per_cpu(cpu_cur_freq, cpu)); 		mutex_unlock(&userspace_mutex);		break;	case CPUFREQ_GOV_STOP:		mutex_lock(&userspace_mutex);		cpus_using_userspace_governor--;		if (cpus_using_userspace_governor == 0) {			cpufreq_unregister_notifier(					&userspace_cpufreq_notifier_block,					CPUFREQ_TRANSITION_NOTIFIER);		} 		per_cpu(cpu_is_managed, cpu) = 0;		per_cpu(cpu_min_freq, cpu) = 0;		per_cpu(cpu_max_freq, cpu) = 0;		per_cpu(cpu_set_freq, cpu) = 0;		pr_debug("managing cpu %u stopped\n", cpu);		mutex_unlock(&userspace_mutex);		break;	case CPUFREQ_GOV_LIMITS:		mutex_lock(&userspace_mutex);		pr_debug("limit event for cpu %u: %u - %u kHz, "			"currently %u kHz, last set to %u kHz\n",			cpu, policy->min, policy->max,			per_cpu(cpu_cur_freq, cpu),			per_cpu(cpu_set_freq, cpu));		if (policy->max < per_cpu(cpu_set_freq, cpu)) {			__cpufreq_driver_target(policy, policy->max,						CPUFREQ_RELATION_H);		} else if (policy->min > per_cpu(cpu_set_freq, cpu)) {			__cpufreq_driver_target(policy, policy->min,						CPUFREQ_RELATION_L);		} else {			__cpufreq_driver_target(policy,						per_cpu(cpu_set_freq, cpu),						CPUFREQ_RELATION_L);		}		per_cpu(cpu_min_freq, cpu) = policy->min;		per_cpu(cpu_max_freq, cpu) = policy->max;		per_cpu(cpu_cur_freq, cpu) = policy->cur;		mutex_unlock(&userspace_mutex);		break;	}	return rc;}  #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACEstatic#endifstruct cpufreq_governor cpufreq_gov_userspace = {	.name		= "userspace",	.governor	= cpufreq_governor_userspace,	.store_setspeed	= cpufreq_set,	.show_setspeed	= show_speed,	.owner		= THIS_MODULE,}; static int __init cpufreq_gov_userspace_init(void){	return cpufreq_register_governor(&cpufreq_gov_userspace);}  static void __exit cpufreq_gov_userspace_exit(void){	cpufreq_unregister_governor(&cpufreq_gov_userspace);}  MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "		"Russell King <rmk@arm.linux.org.uk>");MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");MODULE_LICENSE("GPL"); #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACEfs_initcall(cpufreq_gov_userspace_init);#elsemodule_init(cpufreq_gov_userspace_init);#endifmodule_exit(cpufreq_gov_userspace_exit);