cpufreq.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 *  cpufreq.h - definitions for libcpufreq
  4 *
  5 *  Copyright (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
  6 */
  7
  8#ifndef __CPUPOWER_CPUFREQ_H__
  9#define __CPUPOWER_CPUFREQ_H__
 10
 11struct cpufreq_policy {
 12	unsigned long min;
 13	unsigned long max;
 14	char *governor;
 15};
 16
 17struct cpufreq_available_governors {
 18	char *governor;
 19	struct cpufreq_available_governors *next;
 20	struct cpufreq_available_governors *first;
 21};
 22
 23struct cpufreq_available_frequencies {
 24	unsigned long frequency;
 25	struct cpufreq_available_frequencies *next;
 26	struct cpufreq_available_frequencies *first;
 27};
 28
 29
 30struct cpufreq_affected_cpus {
 31	unsigned int cpu;
 32	struct cpufreq_affected_cpus *next;
 33	struct cpufreq_affected_cpus *first;
 34};
 35
 36struct cpufreq_stats {
 37	unsigned long frequency;
 38	unsigned long long time_in_state;
 39	struct cpufreq_stats *next;
 40	struct cpufreq_stats *first;
 41};
 42
 43
 44
 45#ifdef __cplusplus
 46extern "C" {
 47#endif
 48
 49/* determine current CPU frequency
 50 * - _kernel variant means kernel's opinion of CPU frequency
 51 * - _hardware variant means actual hardware CPU frequency,
 52 *    which is only available to root.
 53 *
 54 * returns 0 on failure, else frequency in kHz.
 55 */
 56
 57unsigned long cpufreq_get_freq_kernel(unsigned int cpu);
 58
 59unsigned long cpufreq_get_freq_hardware(unsigned int cpu);
 60
 61#define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu);
 62
 63
 64/* determine CPU transition latency
 65 *
 66 * returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds
 67 */
 68unsigned long cpufreq_get_transition_latency(unsigned int cpu);
 69
 70
 71/* determine energy performance preference
 72 *
 73 * returns NULL on failure, else the string that represents the energy performance
 74 * preference requested.
 75 */
 76char *cpufreq_get_energy_performance_preference(unsigned int cpu);
 77void cpufreq_put_energy_performance_preference(char *ptr);
 78
 79/* determine hardware CPU frequency limits
 80 *
 81 * These may be limited further by thermal, energy or other
 82 * considerations by cpufreq policy notifiers in the kernel.
 83 */
 84
 85int cpufreq_get_hardware_limits(unsigned int cpu,
 86				unsigned long *min,
 87				unsigned long *max);
 88
 89
 90/* determine CPUfreq driver used
 91 *
 92 * Remember to call cpufreq_put_driver when no longer needed
 93 * to avoid memory leakage, please.
 94 */
 95
 96char *cpufreq_get_driver(unsigned int cpu);
 97
 98void cpufreq_put_driver(char *ptr);
 99
100
101/* determine CPUfreq policy currently used
102 *
103 * Remember to call cpufreq_put_policy when no longer needed
104 * to avoid memory leakage, please.
105 */
106
107
108struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu);
109
110void cpufreq_put_policy(struct cpufreq_policy *policy);
111
112
113/* determine CPUfreq governors currently available
114 *
115 * may be modified by modprobe'ing or rmmod'ing other governors. Please
116 * free allocated memory by calling cpufreq_put_available_governors
117 * after use.
118 */
119
120
121struct cpufreq_available_governors
122*cpufreq_get_available_governors(unsigned int cpu);
123
124void cpufreq_put_available_governors(
125	struct cpufreq_available_governors *first);
126
127
128/* determine CPU frequency states available
129 *
130 * Only present on _some_ ->target() cpufreq drivers. For information purposes
131 * only. Please free allocated memory by calling
132 * cpufreq_put_frequencies after use.
133 */
134
135struct cpufreq_available_frequencies
136*cpufreq_get_available_frequencies(unsigned int cpu);
137
138void cpufreq_put_available_frequencies(
139		struct cpufreq_available_frequencies *first);
140
141struct cpufreq_available_frequencies
142*cpufreq_get_boost_frequencies(unsigned int cpu);
143
144void cpufreq_put_boost_frequencies(
145		struct cpufreq_available_frequencies *first);
146
147
148/* determine affected CPUs
149 *
150 * Remember to call cpufreq_put_affected_cpus when no longer needed
151 * to avoid memory leakage, please.
152 */
153
154struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned
155							int cpu);
156
157void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first);
158
159
160/* determine related CPUs
161 *
162 * Remember to call cpufreq_put_related_cpus when no longer needed
163 * to avoid memory leakage, please.
164 */
165
166struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned
167							int cpu);
168
169void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first);
170
171
172/* determine stats for cpufreq subsystem
173 *
174 * This is not available in all kernel versions or configurations.
175 */
176
177struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu,
178					unsigned long long *total_time);
179
180void cpufreq_put_stats(struct cpufreq_stats *stats);
181
182unsigned long cpufreq_get_transitions(unsigned int cpu);
183
184
185/* set new cpufreq policy
186 *
187 * Tries to set the passed policy as new policy as close as possible,
188 * but results may differ depending e.g. on governors being available.
189 */
190
191int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy);
192
193
194/* modify a policy by only changing min/max freq or governor
195 *
196 * Does not check whether result is what was intended.
197 */
198
199int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq);
200int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq);
201int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
202
203
204/* set a specific frequency
205 *
206 * Does only work if userspace governor can be used and no external
207 * interference (other calls to this function or to set/modify_policy)
208 * occurs. Also does not work on ->range() cpufreq drivers.
209 */
210
211int cpufreq_set_frequency(unsigned int cpu,
212				unsigned long target_frequency);
213
214/*
215 * get the sysfs value from specific table
216 *
217 * Read the value with the sysfs file name from specific table. Does
218 * only work if the cpufreq driver has the specific sysfs interfaces.
219 */
220
221unsigned long cpufreq_get_sysfs_value_from_table(unsigned int cpu,
222						 const char **table,
223						 unsigned int index,
224						 unsigned int size);
225
226#ifdef __cplusplus
227}
228#endif
229
230#endif /* _CPUFREQ_H */