[PATCH] aic7xxx_osm build fix
[cris-mirror.git] / drivers / cpufreq / cpufreq_userspace.c
blobd32bf3593cd31433a40f7a1f70f839a1153e0a63
1 /*
2 * linux/drivers/cpufreq/cpufreq_userspace.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
13 #include <linux/config.h>
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/types.h>
22 #include <linux/fs.h>
23 #include <linux/sysfs.h>
25 #include <asm/uaccess.h>
28 /**
29 * A few values needed by the userspace governor
31 static unsigned int cpu_max_freq[NR_CPUS];
32 static unsigned int cpu_min_freq[NR_CPUS];
33 static unsigned int cpu_cur_freq[NR_CPUS]; /* current CPU freq */
34 static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
35 static unsigned int cpu_is_managed[NR_CPUS];
36 static struct cpufreq_policy current_policy[NR_CPUS];
38 static DECLARE_MUTEX (userspace_sem);
40 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
42 /* keep track of frequency transitions */
43 static int
44 userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
45 void *data)
47 struct cpufreq_freqs *freq = data;
49 dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
50 cpu_cur_freq[freq->cpu] = freq->new;
52 return 0;
55 static struct notifier_block userspace_cpufreq_notifier_block = {
56 .notifier_call = userspace_cpufreq_notifier
60 /**
61 * cpufreq_set - set the CPU frequency
62 * @freq: target frequency in kHz
63 * @cpu: CPU for which the frequency is to be set
65 * Sets the CPU frequency to freq.
67 static int cpufreq_set(unsigned int freq, unsigned int cpu)
69 int ret = -EINVAL;
71 dprintk("cpufreq_set for cpu %u, freq %u kHz\n", cpu, freq);
73 down(&userspace_sem);
74 if (!cpu_is_managed[cpu])
75 goto err;
77 cpu_set_freq[cpu] = freq;
79 if (freq < cpu_min_freq[cpu])
80 freq = cpu_min_freq[cpu];
81 if (freq > cpu_max_freq[cpu])
82 freq = cpu_max_freq[cpu];
85 * We're safe from concurrent calls to ->target() here
86 * as we hold the userspace_sem lock. If we were calling
87 * cpufreq_driver_target, a deadlock situation might occur:
88 * A: cpufreq_set (lock userspace_sem) -> cpufreq_driver_target(lock policy->lock)
89 * B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_sem)
91 ret = __cpufreq_driver_target(&current_policy[cpu], freq,
92 CPUFREQ_RELATION_L);
94 err:
95 up(&userspace_sem);
96 return ret;
100 /************************** sysfs interface ************************/
101 static ssize_t show_speed (struct cpufreq_policy *policy, char *buf)
103 return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);
106 static ssize_t
107 store_speed (struct cpufreq_policy *policy, const char *buf, size_t count)
109 unsigned int freq = 0;
110 unsigned int ret;
112 ret = sscanf (buf, "%u", &freq);
113 if (ret != 1)
114 return -EINVAL;
116 cpufreq_set(freq, policy->cpu);
118 return count;
121 static struct freq_attr freq_attr_scaling_setspeed =
123 .attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },
124 .show = show_speed,
125 .store = store_speed,
128 static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
129 unsigned int event)
131 unsigned int cpu = policy->cpu;
132 switch (event) {
133 case CPUFREQ_GOV_START:
134 if (!cpu_online(cpu))
135 return -EINVAL;
136 BUG_ON(!policy->cur);
137 down(&userspace_sem);
138 cpu_is_managed[cpu] = 1;
139 cpu_min_freq[cpu] = policy->min;
140 cpu_max_freq[cpu] = policy->max;
141 cpu_cur_freq[cpu] = policy->cur;
142 cpu_set_freq[cpu] = policy->cur;
143 sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
144 memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
145 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]);
146 up(&userspace_sem);
147 break;
148 case CPUFREQ_GOV_STOP:
149 down(&userspace_sem);
150 cpu_is_managed[cpu] = 0;
151 cpu_min_freq[cpu] = 0;
152 cpu_max_freq[cpu] = 0;
153 cpu_set_freq[cpu] = 0;
154 sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
155 dprintk("managing cpu %u stopped\n", cpu);
156 up(&userspace_sem);
157 break;
158 case CPUFREQ_GOV_LIMITS:
159 down(&userspace_sem);
160 cpu_min_freq[cpu] = policy->min;
161 cpu_max_freq[cpu] = policy->max;
162 dprintk("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu], cpu_set_freq[cpu]);
163 if (policy->max < cpu_set_freq[cpu]) {
164 __cpufreq_driver_target(&current_policy[cpu], policy->max,
165 CPUFREQ_RELATION_H);
166 } else if (policy->min > cpu_set_freq[cpu]) {
167 __cpufreq_driver_target(&current_policy[cpu], policy->min,
168 CPUFREQ_RELATION_L);
169 } else {
170 __cpufreq_driver_target(&current_policy[cpu], cpu_set_freq[cpu],
171 CPUFREQ_RELATION_L);
173 memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
174 up(&userspace_sem);
175 break;
177 return 0;
181 struct cpufreq_governor cpufreq_gov_userspace = {
182 .name = "userspace",
183 .governor = cpufreq_governor_userspace,
184 .owner = THIS_MODULE,
186 EXPORT_SYMBOL(cpufreq_gov_userspace);
188 static int __init cpufreq_gov_userspace_init(void)
190 cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
191 return cpufreq_register_governor(&cpufreq_gov_userspace);
195 static void __exit cpufreq_gov_userspace_exit(void)
197 cpufreq_unregister_governor(&cpufreq_gov_userspace);
198 cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
202 MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
203 MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
204 MODULE_LICENSE ("GPL");
206 fs_initcall(cpufreq_gov_userspace_init);
207 module_exit(cpufreq_gov_userspace_exit);