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 16 #ifndef __CPUPOWER_CPUFREQ_H__ 17 #define __CPUPOWER_CPUFREQ_H__ 18 19 struct cpufreq_policy { 20 unsigned long min; 21 unsigned long max; 22 char *governor; 23 }; 24 25 struct cpufreq_available_governors { 26 char *governor; 27 struct cpufreq_available_governors *next; 28 struct cpufreq_available_governors *first; 29 }; 30 31 struct cpufreq_available_frequencies { 32 unsigned long frequency; 33 struct cpufreq_available_frequencies *next; 34 struct cpufreq_available_frequencies *first; 35 }; 36 37 38 struct cpufreq_affected_cpus { 39 unsigned int cpu; 40 struct cpufreq_affected_cpus *next; 41 struct cpufreq_affected_cpus *first; 42 }; 43 44 struct cpufreq_stats { 45 unsigned long frequency; 46 unsigned long long time_in_state; 47 struct cpufreq_stats *next; 48 struct cpufreq_stats *first; 49 }; 50 51 52 53 #ifdef __cplusplus 54 extern "C" { 55 #endif 56 57 /* determine current CPU frequency 58 * - _kernel variant means kernel's opinion of CPU frequency 59 * - _hardware variant means actual hardware CPU frequency, 60 * which is only available to root. 61 * 62 * returns 0 on failure, else frequency in kHz. 63 */ 64 65 unsigned long cpufreq_get_freq_kernel(unsigned int cpu); 66 67 unsigned long cpufreq_get_freq_hardware(unsigned int cpu); 68 69 #define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu); 70 71 72 /* determine CPU transition latency 73 * 74 * returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds 75 */ 76 unsigned long cpufreq_get_transition_latency(unsigned int cpu); 77 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 85 int 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 96 char *cpufreq_get_driver(unsigned int cpu); 97 98 void 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 */ 106 107 108 struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu); 109 110 void 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 */ 119 120 121 struct cpufreq_available_governors 122 *cpufreq_get_available_governors(unsigned int cpu); 123 124 void 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_available_frequencies after use. 133 */ 134 135 struct cpufreq_available_frequencies 136 *cpufreq_get_available_frequencies(unsigned int cpu); 137 138 void cpufreq_put_available_frequencies( 139 struct cpufreq_available_frequencies *first); 140 141 142 /* determine affected CPUs 143 * 144 * Remember to call cpufreq_put_affected_cpus when no longer needed 145 * to avoid memory leakage, please. 146 */ 147 148 struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned 149 int cpu); 150 151 void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first); 152 153 154 /* determine related CPUs 155 * 156 * Remember to call cpufreq_put_related_cpus when no longer needed 157 * to avoid memory leakage, please. 158 */ 159 160 struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned 161 int cpu); 162 163 void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first); 164 165 166 /* determine stats for cpufreq subsystem 167 * 168 * This is not available in all kernel versions or configurations. 169 */ 170 171 struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu, 172 unsigned long long *total_time); 173 174 void cpufreq_put_stats(struct cpufreq_stats *stats); 175 176 unsigned long cpufreq_get_transitions(unsigned int cpu); 177 178 179 /* set new cpufreq policy 180 * 181 * Tries to set the passed policy as new policy as close as possible, 182 * but results may differ depending e.g. on governors being available. 183 */ 184 185 int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy); 186 187 188 /* modify a policy by only changing min/max freq or governor 189 * 190 * Does not check whether result is what was intended. 191 */ 192 193 int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq); 194 int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq); 195 int cpufreq_modify_policy_governor(unsigned int cpu, char *governor); 196 197 198 /* set a specific frequency 199 * 200 * Does only work if userspace governor can be used and no external 201 * interference (other calls to this function or to set/modify_policy) 202 * occurs. Also does not work on ->range() cpufreq drivers. 203 */ 204 205 int cpufreq_set_frequency(unsigned int cpu, 206 unsigned long target_frequency); 207 208 #ifdef __cplusplus 209 } 210 #endif 211 212 #endif /* _CPUFREQ_H */ 213