2 * cpufreq.h - definitions for libcpufreq
4 * Copyright (C) 2004-2009 Dominik Brodowski <linux@dominikbrodowski.de>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, version 2 of the License.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 struct cpufreq_policy {
29 struct cpufreq_available_governors {
31 struct cpufreq_available_governors *next;
32 struct cpufreq_available_governors *first;
35 struct cpufreq_available_frequencies {
36 unsigned long frequency;
37 struct cpufreq_available_frequencies *next;
38 struct cpufreq_available_frequencies *first;
42 struct cpufreq_affected_cpus {
44 struct cpufreq_affected_cpus *next;
45 struct cpufreq_affected_cpus *first;
48 struct cpufreq_stats {
49 unsigned long frequency;
50 unsigned long long time_in_state;
51 struct cpufreq_stats *next;
52 struct cpufreq_stats *first;
62 * returns 0 if the specified CPU is present (it doesn't say
63 * whether it is online!), and an error value if not.
66 extern int cpufreq_cpu_exists(unsigned int cpu);
68 /* determine current CPU frequency
69 * - _kernel variant means kernel's opinion of CPU frequency
70 * - _hardware variant means actual hardware CPU frequency,
71 * which is only available to root.
73 * returns 0 on failure, else frequency in kHz.
76 extern unsigned long cpufreq_get_freq_kernel(unsigned int cpu);
78 extern unsigned long cpufreq_get_freq_hardware(unsigned int cpu);
80 #define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu);
83 /* determine CPU transition latency
85 * returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds
87 extern unsigned long cpufreq_get_transition_latency(unsigned int cpu);
90 /* determine hardware CPU frequency limits
92 * These may be limited further by thermal, energy or other
93 * considerations by cpufreq policy notifiers in the kernel.
96 extern int cpufreq_get_hardware_limits(unsigned int cpu,
101 /* determine CPUfreq driver used
103 * Remember to call cpufreq_put_driver when no longer needed
104 * to avoid memory leakage, please.
107 extern char * cpufreq_get_driver(unsigned int cpu);
109 extern void cpufreq_put_driver(char * ptr);
112 /* determine CPUfreq policy currently used
114 * Remember to call cpufreq_put_policy when no longer needed
115 * to avoid memory leakage, please.
119 extern struct cpufreq_policy * cpufreq_get_policy(unsigned int cpu);
121 extern void cpufreq_put_policy(struct cpufreq_policy *policy);
124 /* determine CPUfreq governors currently available
126 * may be modified by modprobe'ing or rmmod'ing other governors. Please
127 * free allocated memory by calling cpufreq_put_available_governors
132 extern struct cpufreq_available_governors * cpufreq_get_available_governors(unsigned int cpu);
134 extern void cpufreq_put_available_governors(struct cpufreq_available_governors *first);
137 /* determine CPU frequency states available
139 * only present on _some_ ->target() cpufreq drivers. For information purposes
140 * only. Please free allocated memory by calling cpufreq_put_available_frequencies
144 extern struct cpufreq_available_frequencies * cpufreq_get_available_frequencies(unsigned int cpu);
146 extern void cpufreq_put_available_frequencies(struct cpufreq_available_frequencies *first);
149 /* determine affected CPUs
151 * Remember to call cpufreq_put_affected_cpus when no longer needed
152 * to avoid memory leakage, please.
155 extern struct cpufreq_affected_cpus * cpufreq_get_affected_cpus(unsigned int cpu);
157 extern void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first);
160 /* determine related CPUs
162 * Remember to call cpufreq_put_related_cpus when no longer needed
163 * to avoid memory leakage, please.
166 extern struct cpufreq_affected_cpus * cpufreq_get_related_cpus(unsigned int cpu);
168 extern void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first);
171 /* determine stats for cpufreq subsystem
173 * This is not available in all kernel versions or configurations.
176 extern struct cpufreq_stats * cpufreq_get_stats(unsigned int cpu, unsigned long long *total_time);
178 extern void cpufreq_put_stats(struct cpufreq_stats *stats);
180 extern unsigned long cpufreq_get_transitions(unsigned int cpu);
183 /* set new cpufreq policy
185 * Tries to set the passed policy as new policy as close as possible,
186 * but results may differ depending e.g. on governors being available.
189 extern int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy);
192 /* modify a policy by only changing min/max freq or governor
194 * Does not check whether result is what was intended.
197 extern int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq);
198 extern int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq);
199 extern int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
202 /* set a specific frequency
204 * Does only work if userspace governor can be used and no external
205 * interference (other calls to this function or to set/modify_policy)
206 * occurs. Also does not work on ->range() cpufreq drivers.
209 extern int cpufreq_set_frequency(unsigned int cpu, unsigned long target_frequency);
215 #endif /* _CPUFREQ_H */