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c0672860 | 1 | |
1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
153d7f3f | 21 | #include <linux/cpu.h> |
1da177e4 LT |
22 | #include <linux/types.h> |
23 | #include <linux/fs.h> | |
24 | #include <linux/sysfs.h> | |
3fc54d37 | 25 | #include <linux/mutex.h> |
1da177e4 LT |
26 | |
27 | #include <asm/uaccess.h> | |
28 | ||
29 | ||
30 | /** | |
31 | * A few values needed by the userspace governor | |
32 | */ | |
b38868aa MT |
33 | static DEFINE_PER_CPU(unsigned int, cpu_max_freq); |
34 | static DEFINE_PER_CPU(unsigned int, cpu_min_freq); | |
35 | static DEFINE_PER_CPU(unsigned int, cpu_cur_freq); /* current CPU freq */ | |
36 | static DEFINE_PER_CPU(unsigned int, cpu_set_freq); /* CPU freq desired by | |
37 | userspace */ | |
38 | static DEFINE_PER_CPU(unsigned int, cpu_is_managed); | |
1da177e4 | 39 | |
3fc54d37 | 40 | static DEFINE_MUTEX (userspace_mutex); |
c7f652e0 | 41 | static int cpus_using_userspace_governor; |
1da177e4 | 42 | |
b38868aa MT |
43 | #define dprintk(msg...) \ |
44 | cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg) | |
1da177e4 LT |
45 | |
46 | /* keep track of frequency transitions */ | |
32ee8c3e | 47 | static int |
1da177e4 LT |
48 | userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
49 | void *data) | |
50 | { | |
51 | struct cpufreq_freqs *freq = data; | |
52 | ||
b38868aa | 53 | if (!per_cpu(cpu_is_managed, freq->cpu)) |
c7f652e0 VP |
54 | return 0; |
55 | ||
56 | dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", | |
57 | freq->cpu, freq->new); | |
b38868aa | 58 | per_cpu(cpu_cur_freq, freq->cpu) = freq->new; |
1da177e4 LT |
59 | |
60 | return 0; | |
61 | } | |
62 | ||
63 | static struct notifier_block userspace_cpufreq_notifier_block = { | |
64 | .notifier_call = userspace_cpufreq_notifier | |
65 | }; | |
66 | ||
67 | ||
32ee8c3e | 68 | /** |
1da177e4 | 69 | * cpufreq_set - set the CPU frequency |
9e76988e | 70 | * @policy: pointer to policy struct where freq is being set |
1da177e4 | 71 | * @freq: target frequency in kHz |
1da177e4 LT |
72 | * |
73 | * Sets the CPU frequency to freq. | |
74 | */ | |
9e76988e | 75 | static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq) |
1da177e4 LT |
76 | { |
77 | int ret = -EINVAL; | |
78 | ||
c0672860 | 79 | dprintk("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq); |
1da177e4 | 80 | |
3fc54d37 | 81 | mutex_lock(&userspace_mutex); |
b38868aa | 82 | if (!per_cpu(cpu_is_managed, policy->cpu)) |
1da177e4 LT |
83 | goto err; |
84 | ||
b38868aa | 85 | per_cpu(cpu_set_freq, policy->cpu) = freq; |
1da177e4 | 86 | |
b38868aa MT |
87 | if (freq < per_cpu(cpu_min_freq, policy->cpu)) |
88 | freq = per_cpu(cpu_min_freq, policy->cpu); | |
89 | if (freq > per_cpu(cpu_max_freq, policy->cpu)) | |
90 | freq = per_cpu(cpu_max_freq, policy->cpu); | |
1da177e4 LT |
91 | |
92 | /* | |
93 | * We're safe from concurrent calls to ->target() here | |
3fc54d37 | 94 | * as we hold the userspace_mutex lock. If we were calling |
1da177e4 | 95 | * cpufreq_driver_target, a deadlock situation might occur: |
3fc54d37 | 96 | * A: cpufreq_set (lock userspace_mutex) -> cpufreq_driver_target(lock policy->lock) |
97 | * B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_mutex) | |
1da177e4 | 98 | */ |
c0672860 | 99 | ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L); |
1da177e4 LT |
100 | |
101 | err: | |
3fc54d37 | 102 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
103 | return ret; |
104 | } | |
105 | ||
106 | ||
9e76988e | 107 | static ssize_t show_speed(struct cpufreq_policy *policy, char *buf) |
1da177e4 | 108 | { |
b38868aa | 109 | return sprintf(buf, "%u\n", per_cpu(cpu_cur_freq, policy->cpu)); |
1da177e4 LT |
110 | } |
111 | ||
1da177e4 LT |
112 | static int cpufreq_governor_userspace(struct cpufreq_policy *policy, |
113 | unsigned int event) | |
114 | { | |
115 | unsigned int cpu = policy->cpu; | |
914f7c31 JG |
116 | int rc = 0; |
117 | ||
1da177e4 LT |
118 | switch (event) { |
119 | case CPUFREQ_GOV_START: | |
120 | if (!cpu_online(cpu)) | |
121 | return -EINVAL; | |
122 | BUG_ON(!policy->cur); | |
3fc54d37 | 123 | mutex_lock(&userspace_mutex); |
914f7c31 | 124 | |
c7f652e0 VP |
125 | if (cpus_using_userspace_governor == 0) { |
126 | cpufreq_register_notifier( | |
127 | &userspace_cpufreq_notifier_block, | |
128 | CPUFREQ_TRANSITION_NOTIFIER); | |
129 | } | |
130 | cpus_using_userspace_governor++; | |
131 | ||
b38868aa MT |
132 | per_cpu(cpu_is_managed, cpu) = 1; |
133 | per_cpu(cpu_min_freq, cpu) = policy->min; | |
134 | per_cpu(cpu_max_freq, cpu) = policy->max; | |
135 | per_cpu(cpu_cur_freq, cpu) = policy->cur; | |
136 | per_cpu(cpu_set_freq, cpu) = policy->cur; | |
137 | dprintk("managing cpu %u started " | |
138 | "(%u - %u kHz, currently %u kHz)\n", | |
139 | cpu, | |
140 | per_cpu(cpu_min_freq, cpu), | |
141 | per_cpu(cpu_max_freq, cpu), | |
142 | per_cpu(cpu_cur_freq, cpu)); | |
9e76988e | 143 | |
3fc54d37 | 144 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
145 | break; |
146 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 147 | mutex_lock(&userspace_mutex); |
c7f652e0 VP |
148 | cpus_using_userspace_governor--; |
149 | if (cpus_using_userspace_governor == 0) { | |
150 | cpufreq_unregister_notifier( | |
151 | &userspace_cpufreq_notifier_block, | |
152 | CPUFREQ_TRANSITION_NOTIFIER); | |
153 | } | |
154 | ||
b38868aa MT |
155 | per_cpu(cpu_is_managed, cpu) = 0; |
156 | per_cpu(cpu_min_freq, cpu) = 0; | |
157 | per_cpu(cpu_max_freq, cpu) = 0; | |
158 | per_cpu(cpu_set_freq, cpu) = 0; | |
1da177e4 | 159 | dprintk("managing cpu %u stopped\n", cpu); |
3fc54d37 | 160 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
161 | break; |
162 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 163 | mutex_lock(&userspace_mutex); |
b38868aa | 164 | dprintk("limit event for cpu %u: %u - %u kHz, " |
c0672860 TR |
165 | "currently %u kHz, last set to %u kHz\n", |
166 | cpu, policy->min, policy->max, | |
b38868aa MT |
167 | per_cpu(cpu_cur_freq, cpu), |
168 | per_cpu(cpu_set_freq, cpu)); | |
169 | if (policy->max < per_cpu(cpu_set_freq, cpu)) { | |
c0672860 TR |
170 | __cpufreq_driver_target(policy, policy->max, |
171 | CPUFREQ_RELATION_H); | |
b38868aa | 172 | } else if (policy->min > per_cpu(cpu_set_freq, cpu)) { |
c0672860 TR |
173 | __cpufreq_driver_target(policy, policy->min, |
174 | CPUFREQ_RELATION_L); | |
b38868aa MT |
175 | } else { |
176 | __cpufreq_driver_target(policy, | |
177 | per_cpu(cpu_set_freq, cpu), | |
c0672860 TR |
178 | CPUFREQ_RELATION_L); |
179 | } | |
b38868aa MT |
180 | per_cpu(cpu_min_freq, cpu) = policy->min; |
181 | per_cpu(cpu_max_freq, cpu) = policy->max; | |
182 | per_cpu(cpu_cur_freq, cpu) = policy->cur; | |
3fc54d37 | 183 | mutex_unlock(&userspace_mutex); |
1da177e4 LT |
184 | break; |
185 | } | |
914f7c31 | 186 | return rc; |
1da177e4 LT |
187 | } |
188 | ||
189 | ||
c4d14bc0 SW |
190 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE |
191 | static | |
192 | #endif | |
1da177e4 LT |
193 | struct cpufreq_governor cpufreq_gov_userspace = { |
194 | .name = "userspace", | |
195 | .governor = cpufreq_governor_userspace, | |
9e76988e VP |
196 | .store_setspeed = cpufreq_set, |
197 | .show_setspeed = show_speed, | |
1da177e4 LT |
198 | .owner = THIS_MODULE, |
199 | }; | |
1da177e4 LT |
200 | |
201 | static int __init cpufreq_gov_userspace_init(void) | |
202 | { | |
1da177e4 LT |
203 | return cpufreq_register_governor(&cpufreq_gov_userspace); |
204 | } | |
205 | ||
206 | ||
207 | static void __exit cpufreq_gov_userspace_exit(void) | |
208 | { | |
209 | cpufreq_unregister_governor(&cpufreq_gov_userspace); | |
1da177e4 LT |
210 | } |
211 | ||
212 | ||
213 | MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>"); | |
214 | MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'"); | |
215 | MODULE_LICENSE ("GPL"); | |
216 | ||
6915719b | 217 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE |
1da177e4 | 218 | fs_initcall(cpufreq_gov_userspace_init); |
6915719b JW |
219 | #else |
220 | module_init(cpufreq_gov_userspace_init); | |
221 | #endif | |
1da177e4 | 222 | module_exit(cpufreq_gov_userspace_exit); |