/* *  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/config.h>#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/types.h>#include <linux/fs.h>#include <linux/sysfs.h>#include <linux/mutex.h> #include <asm/uaccess.h>  /** * A few values needed by the userspace governor */static unsigned int	cpu_max_freq[NR_CPUS];static unsigned int	cpu_min_freq[NR_CPUS];static unsigned int	cpu_cur_freq[NR_CPUS]; /* current CPU freq */static unsigned int	cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */static unsigned int	cpu_is_managed[NR_CPUS]; static DEFINE_MUTEX	(userspace_mutex); #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg) /* keep track of frequency transitions */static intuserspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,                       void *data){        struct cpufreq_freqs *freq = data; 	dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);	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 * @freq: target frequency in kHz * @cpu: CPU for which the frequency is to be set * * Sets the CPU frequency to freq. */static int cpufreq_set(unsigned int freq, struct cpufreq_policy *policy){	int ret = -EINVAL; 	dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); 	mutex_lock(&userspace_mutex);	if (!cpu_is_managed[policy->cpu])		goto err; 	cpu_set_freq[policy->cpu] = freq; 	if (freq < cpu_min_freq[policy->cpu])		freq = cpu_min_freq[policy->cpu];	if (freq > cpu_max_freq[policy->cpu])		freq = 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;}  /************************** sysfs interface ************************/static ssize_t show_speed (struct cpufreq_policy *policy, char *buf){	return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);} static ssize_tstore_speed (struct cpufreq_policy *policy, const char *buf, size_t count){	unsigned int freq = 0;	unsigned int ret; 	ret = sscanf (buf, "%u", &freq);	if (ret != 1)		return -EINVAL; 	cpufreq_set(freq, policy); 	return count;} static struct freq_attr freq_attr_scaling_setspeed ={	.attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },	.show = show_speed,	.store = store_speed,}; static int cpufreq_governor_userspace(struct cpufreq_policy *policy,				   unsigned int event){	unsigned int cpu = policy->cpu;	switch (event) {	case CPUFREQ_GOV_START:		if (!cpu_online(cpu))			return -EINVAL;		BUG_ON(!policy->cur);		mutex_lock(&userspace_mutex);		cpu_is_managed[cpu] = 1;		cpu_min_freq[cpu] = policy->min;		cpu_max_freq[cpu] = policy->max;		cpu_cur_freq[cpu] = policy->cur;		cpu_set_freq[cpu] = policy->cur;		sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);		dprintk("managing cpu %u started (%u - %u kHz, currently %u kHz)\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu]);		mutex_unlock(&userspace_mutex);		break;	case CPUFREQ_GOV_STOP:		mutex_lock(&userspace_mutex);		cpu_is_managed[cpu] = 0;		cpu_min_freq[cpu] = 0;		cpu_max_freq[cpu] = 0;		cpu_set_freq[cpu] = 0;		sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);		dprintk("managing cpu %u stopped\n", cpu);		mutex_unlock(&userspace_mutex);		break;	case CPUFREQ_GOV_LIMITS:		mutex_lock(&userspace_mutex);		dprintk("limit event for cpu %u: %u - %u kHz,"			"currently %u kHz, last set to %u kHz\n",			cpu, policy->min, policy->max,			cpu_cur_freq[cpu], cpu_set_freq[cpu]);		if (policy->max < cpu_set_freq[cpu]) {			__cpufreq_driver_target(policy, policy->max,						CPUFREQ_RELATION_H);		}		else if (policy->min > cpu_set_freq[cpu]) {			__cpufreq_driver_target(policy, policy->min,						CPUFREQ_RELATION_L);		}		else {			__cpufreq_driver_target(policy, cpu_set_freq[cpu],						CPUFREQ_RELATION_L);		}		cpu_min_freq[cpu] = policy->min;		cpu_max_freq[cpu] = policy->max;		cpu_cur_freq[cpu] = policy->cur;		mutex_unlock(&userspace_mutex);		break;	}	return 0;}  struct cpufreq_governor cpufreq_gov_userspace = {	.name		= "userspace",	.governor	= cpufreq_governor_userspace,	.owner		= THIS_MODULE,};EXPORT_SYMBOL(cpufreq_gov_userspace); static int __init cpufreq_gov_userspace_init(void){	cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);	return cpufreq_register_governor(&cpufreq_gov_userspace);}  static void __exit cpufreq_gov_userspace_exit(void){	cpufreq_unregister_governor(&cpufreq_gov_userspace);        cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);}  MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");MODULE_LICENSE ("GPL"); fs_initcall(cpufreq_gov_userspace_init);module_exit(cpufreq_gov_userspace_exit);