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