1
  2/*
  3 *  linux/drivers/cpufreq/cpufreq_userspace.c
  4 *
  5 *  Copyright (C)  2001 Russell King
  6 *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 */
 13
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/smp.h>
 17#include <linux/init.h>
 18#include <linux/spinlock.h>
 19#include <linux/interrupt.h>
 20#include <linux/cpufreq.h>
 21#include <linux/cpu.h>
 22#include <linux/types.h>
 23#include <linux/fs.h>
 24#include <linux/sysfs.h>
 25#include <linux/mutex.h>
 26
 27/**
 28 * A few values needed by the userspace governor
 29 */
 30static DEFINE_PER_CPU(unsigned int, cpu_max_freq);
 31static DEFINE_PER_CPU(unsigned int, cpu_min_freq);
 32static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */
 33static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by
 34							userspace */
 35static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
 36
 37static DEFINE_MUTEX(userspace_mutex);
 38static int cpus_using_userspace_governor;
 39
 40/* keep track of frequency transitions */
 41static int
 42userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 43	void *data)
 44{
 45	struct cpufreq_freqs *freq = data;
 46
 47	if (!per_cpu(cpu_is_managed, freq->cpu))
 48		return 0;
 49
 50	pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n",
 51			freq->cpu, freq->new);
 52	per_cpu(cpu_cur_freq, freq->cpu) = freq->new;
 
 
 53
 54	return 0;
 55}
 56
 57static struct notifier_block userspace_cpufreq_notifier_block = {
 58	.notifier_call  = userspace_cpufreq_notifier
 59};
 60
 61
 62/**
 63 * cpufreq_set - set the CPU frequency
 64 * @policy: pointer to policy struct where freq is being set
 65 * @freq: target frequency in kHz
 66 *
 67 * Sets the CPU frequency to freq.
 68 */
 69static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
 70{
 71	int ret = -EINVAL;
 72
 73	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
 74
 75	mutex_lock(&userspace_mutex);
 76	if (!per_cpu(cpu_is_managed, policy->cpu))
 77		goto err;
 78
 79	per_cpu(cpu_set_freq, policy->cpu) = freq;
 80
 81	if (freq < per_cpu(cpu_min_freq, policy->cpu))
 82		freq = per_cpu(cpu_min_freq, policy->cpu);
 83	if (freq > per_cpu(cpu_max_freq, policy->cpu))
 84		freq = per_cpu(cpu_max_freq, policy->cpu);
 85
 86	/*
 87	 * We're safe from concurrent calls to ->target() here
 88	 * as we hold the userspace_mutex lock. If we were calling
 89	 * cpufreq_driver_target, a deadlock situation might occur:
 90	 * A: cpufreq_set (lock userspace_mutex) ->
 91	 *      cpufreq_driver_target(lock policy->lock)
 92	 * B: cpufreq_set_policy(lock policy->lock) ->
 93	 *      __cpufreq_governor ->
 94	 *         cpufreq_governor_userspace (lock userspace_mutex)
 95	 */
 96	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
 97
 98 err:
 99	mutex_unlock(&userspace_mutex);
100	return ret;
101}
102
103
104static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
105{
106	return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu));
107}
108
109static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
110				   unsigned int event)
111{
112	unsigned int cpu = policy->cpu;
113	int rc = 0;
114
115	switch (event) {
116	case CPUFREQ_GOV_START:
117		if (!cpu_online(cpu))
118			return -EINVAL;
119		BUG_ON(!policy->cur);
120		mutex_lock(&userspace_mutex);
121
122		if (cpus_using_userspace_governor == 0) {
123			cpufreq_register_notifier(
124					&userspace_cpufreq_notifier_block,
125					CPUFREQ_TRANSITION_NOTIFIER);
126		}
127		cpus_using_userspace_governor++;
128
129		per_cpu(cpu_is_managed, cpu) = 1;
130		per_cpu(cpu_min_freq, cpu) = policy->min;
131		per_cpu(cpu_max_freq, cpu) = policy->max;
132		per_cpu(cpu_cur_freq, cpu) = policy->cur;
133		per_cpu(cpu_set_freq, cpu) = policy->cur;
134		pr_debug("managing cpu %u started "
135			"(%u - %u kHz, currently %u kHz)\n",
136				cpu,
137				per_cpu(cpu_min_freq, cpu),
138				per_cpu(cpu_max_freq, cpu),
139				per_cpu(cpu_cur_freq, cpu));
140
141		mutex_unlock(&userspace_mutex);
142		break;
143	case CPUFREQ_GOV_STOP:
144		mutex_lock(&userspace_mutex);
145		cpus_using_userspace_governor--;
146		if (cpus_using_userspace_governor == 0) {
147			cpufreq_unregister_notifier(
148					&userspace_cpufreq_notifier_block,
149					CPUFREQ_TRANSITION_NOTIFIER);
150		}
151
152		per_cpu(cpu_is_managed, cpu) = 0;
153		per_cpu(cpu_min_freq, cpu) = 0;
154		per_cpu(cpu_max_freq, cpu) = 0;
155		per_cpu(cpu_set_freq, cpu) = 0;
156		pr_debug("managing cpu %u stopped\n", cpu);
157		mutex_unlock(&userspace_mutex);
158		break;
159	case CPUFREQ_GOV_LIMITS:
160		mutex_lock(&userspace_mutex);
161		pr_debug("limit event for cpu %u: %u - %u kHz, "
162			"currently %u kHz, last set to %u kHz\n",
163			cpu, policy->min, policy->max,
164			per_cpu(cpu_cur_freq, cpu),
165			per_cpu(cpu_set_freq, cpu));
166		if (policy->max < per_cpu(cpu_set_freq, cpu)) {
167			__cpufreq_driver_target(policy, policy->max,
168						CPUFREQ_RELATION_H);
169		} else if (policy->min > per_cpu(cpu_set_freq, cpu)) {
170			__cpufreq_driver_target(policy, policy->min,
171						CPUFREQ_RELATION_L);
172		} else {
173			__cpufreq_driver_target(policy,
174						per_cpu(cpu_set_freq, cpu),
175						CPUFREQ_RELATION_L);
176		}
177		per_cpu(cpu_min_freq, cpu) = policy->min;
178		per_cpu(cpu_max_freq, cpu) = policy->max;
179		per_cpu(cpu_cur_freq, cpu) = policy->cur;
180		mutex_unlock(&userspace_mutex);
181		break;
182	}
183	return rc;
184}
185
186
187#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
188static
189#endif
190struct cpufreq_governor cpufreq_gov_userspace = {
191	.name		= "userspace",
192	.governor	= cpufreq_governor_userspace,
193	.store_setspeed	= cpufreq_set,
194	.show_setspeed	= show_speed,
195	.owner		= THIS_MODULE,
196};
197
198static int __init cpufreq_gov_userspace_init(void)
199{
200	return cpufreq_register_governor(&cpufreq_gov_userspace);
201}
202
203
204static void __exit cpufreq_gov_userspace_exit(void)
205{
206	cpufreq_unregister_governor(&cpufreq_gov_userspace);
207}
208
209
210MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
211		"Russell King <rmk@arm.linux.org.uk>");
212MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
213MODULE_LICENSE("GPL");
214
215#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
216fs_initcall(cpufreq_gov_userspace_init);
217#else
218module_init(cpufreq_gov_userspace_init);
219#endif
220module_exit(cpufreq_gov_userspace_exit);

  1
  2/*
  3 *  linux/drivers/cpufreq/cpufreq_userspace.c
  4 *
  5 *  Copyright (C)  2001 Russell King
  6 *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 */
 13
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/smp.h>
 17#include <linux/init.h>
 18#include <linux/spinlock.h>
 19#include <linux/interrupt.h>
 20#include <linux/cpufreq.h>
 21#include <linux/cpu.h>
 22#include <linux/types.h>
 23#include <linux/fs.h>
 24#include <linux/sysfs.h>
 25#include <linux/mutex.h>
 26
 27/**
 28 * A few values needed by the userspace governor
 29 */
 30static DEFINE_PER_CPU(unsigned int, cpu_max_freq);
 31static DEFINE_PER_CPU(unsigned int, cpu_min_freq);
 32static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */
 33static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by
 34							userspace */
 35static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
 36
 37static DEFINE_MUTEX(userspace_mutex);
 38static int cpus_using_userspace_governor;
 39
 40/* keep track of frequency transitions */
 41static int
 42userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 43	void *data)
 44{
 45	struct cpufreq_freqs *freq = data;
 46
 47	if (!per_cpu(cpu_is_managed, freq->cpu))
 48		return 0;
 49
 50	if (val == CPUFREQ_POSTCHANGE) {
 51		pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n",
 52				freq->cpu, freq->new);
 53		per_cpu(cpu_cur_freq, freq->cpu) = freq->new;
 54	}
 55
 56	return 0;
 57}
 58
 59static struct notifier_block userspace_cpufreq_notifier_block = {
 60	.notifier_call  = userspace_cpufreq_notifier
 61};
 62
 63
 64/**
 65 * cpufreq_set - set the CPU frequency
 66 * @policy: pointer to policy struct where freq is being set
 67 * @freq: target frequency in kHz
 68 *
 69 * Sets the CPU frequency to freq.
 70 */
 71static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
 72{
 73	int ret = -EINVAL;
 74
 75	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
 76
 77	mutex_lock(&userspace_mutex);
 78	if (!per_cpu(cpu_is_managed, policy->cpu))
 79		goto err;
 80
 81	per_cpu(cpu_set_freq, policy->cpu) = freq;
 82
 83	if (freq < per_cpu(cpu_min_freq, policy->cpu))
 84		freq = per_cpu(cpu_min_freq, policy->cpu);
 85	if (freq > per_cpu(cpu_max_freq, policy->cpu))
 86		freq = per_cpu(cpu_max_freq, policy->cpu);
 87
 88	/*
 89	 * We're safe from concurrent calls to ->target() here
 90	 * as we hold the userspace_mutex lock. If we were calling
 91	 * cpufreq_driver_target, a deadlock situation might occur:
 92	 * A: cpufreq_set (lock userspace_mutex) ->
 93	 *      cpufreq_driver_target(lock policy->lock)
 94	 * B: cpufreq_set_policy(lock policy->lock) ->
 95	 *      __cpufreq_governor ->
 96	 *         cpufreq_governor_userspace (lock userspace_mutex)
 97	 */
 98	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
 99
100 err:
101	mutex_unlock(&userspace_mutex);
102	return ret;
103}
104
105
106static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
107{
108	return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu));
109}
110
111static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
112				   unsigned int event)
113{
114	unsigned int cpu = policy->cpu;
115	int rc = 0;
116
117	switch (event) {
118	case CPUFREQ_GOV_START:
119		if (!cpu_online(cpu))
120			return -EINVAL;
121		BUG_ON(!policy->cur);
122		mutex_lock(&userspace_mutex);
123
124		if (cpus_using_userspace_governor == 0) {
125			cpufreq_register_notifier(
126					&userspace_cpufreq_notifier_block,
127					CPUFREQ_TRANSITION_NOTIFIER);
128		}
129		cpus_using_userspace_governor++;
130
131		per_cpu(cpu_is_managed, cpu) = 1;
132		per_cpu(cpu_min_freq, cpu) = policy->min;
133		per_cpu(cpu_max_freq, cpu) = policy->max;
134		per_cpu(cpu_cur_freq, cpu) = policy->cur;
135		per_cpu(cpu_set_freq, cpu) = policy->cur;
136		pr_debug("managing cpu %u started "
137			"(%u - %u kHz, currently %u kHz)\n",
138				cpu,
139				per_cpu(cpu_min_freq, cpu),
140				per_cpu(cpu_max_freq, cpu),
141				per_cpu(cpu_cur_freq, cpu));
142
143		mutex_unlock(&userspace_mutex);
144		break;
145	case CPUFREQ_GOV_STOP:
146		mutex_lock(&userspace_mutex);
147		cpus_using_userspace_governor--;
148		if (cpus_using_userspace_governor == 0) {
149			cpufreq_unregister_notifier(
150					&userspace_cpufreq_notifier_block,
151					CPUFREQ_TRANSITION_NOTIFIER);
152		}
153
154		per_cpu(cpu_is_managed, cpu) = 0;
155		per_cpu(cpu_min_freq, cpu) = 0;
156		per_cpu(cpu_max_freq, cpu) = 0;
157		per_cpu(cpu_set_freq, cpu) = 0;
158		pr_debug("managing cpu %u stopped\n", cpu);
159		mutex_unlock(&userspace_mutex);
160		break;
161	case CPUFREQ_GOV_LIMITS:
162		mutex_lock(&userspace_mutex);
163		pr_debug("limit event for cpu %u: %u - %u kHz, "
164			"currently %u kHz, last set to %u kHz\n",
165			cpu, policy->min, policy->max,
166			per_cpu(cpu_cur_freq, cpu),
167			per_cpu(cpu_set_freq, cpu));
168		if (policy->max < per_cpu(cpu_set_freq, cpu)) {
169			__cpufreq_driver_target(policy, policy->max,
170						CPUFREQ_RELATION_H);
171		} else if (policy->min > per_cpu(cpu_set_freq, cpu)) {
172			__cpufreq_driver_target(policy, policy->min,
173						CPUFREQ_RELATION_L);
174		} else {
175			__cpufreq_driver_target(policy,
176						per_cpu(cpu_set_freq, cpu),
177						CPUFREQ_RELATION_L);
178		}
179		per_cpu(cpu_min_freq, cpu) = policy->min;
180		per_cpu(cpu_max_freq, cpu) = policy->max;
181		per_cpu(cpu_cur_freq, cpu) = policy->cur;
182		mutex_unlock(&userspace_mutex);
183		break;
184	}
185	return rc;
186}
187
188
189#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
190static
191#endif
192struct cpufreq_governor cpufreq_gov_userspace = {
193	.name		= "userspace",
194	.governor	= cpufreq_governor_userspace,
195	.store_setspeed	= cpufreq_set,
196	.show_setspeed	= show_speed,
197	.owner		= THIS_MODULE,
198};
199
200static int __init cpufreq_gov_userspace_init(void)
201{
202	return cpufreq_register_governor(&cpufreq_gov_userspace);
203}
204
205
206static void __exit cpufreq_gov_userspace_exit(void)
207{
208	cpufreq_unregister_governor(&cpufreq_gov_userspace);
209}
210
211
212MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
213		"Russell King <rmk@arm.linux.org.uk>");
214MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
215MODULE_LICENSE("GPL");
216
217#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
218fs_initcall(cpufreq_gov_userspace_init);
219#else
220module_init(cpufreq_gov_userspace_init);
221#endif
222module_exit(cpufreq_gov_userspace_exit);