| Current File : //usr/include/cpufreq.h |
/*
* cpufreq.h - definitions for libcpufreq
*
* Copyright (C) 2004-2009 Dominik Brodowski <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _CPUFREQ_H
#define _CPUFREQ_H 1
struct cpufreq_policy {
unsigned long min;
unsigned long max;
char *governor;
};
struct cpufreq_available_governors {
char *governor;
struct cpufreq_available_governors *next;
struct cpufreq_available_governors *first;
};
struct cpufreq_available_frequencies {
unsigned long frequency;
struct cpufreq_available_frequencies *next;
struct cpufreq_available_frequencies *first;
};
struct cpufreq_affected_cpus {
unsigned int cpu;
struct cpufreq_affected_cpus *next;
struct cpufreq_affected_cpus *first;
};
struct cpufreq_stats {
unsigned long frequency;
unsigned long long time_in_state;
struct cpufreq_stats *next;
struct cpufreq_stats *first;
};
#ifdef __cplusplus
extern "C" {
#endif
/*
* returns 0 if the specified CPU is present (it doesn't say
* whether it is online!), and an error value if not.
*/
extern int cpufreq_cpu_exists(unsigned int cpu);
/* determine current CPU frequency
* - _kernel variant means kernel's opinion of CPU frequency
* - _hardware variant means actual hardware CPU frequency,
* which is only available to root.
*
* returns 0 on failure, else frequency in kHz.
*/
extern unsigned long cpufreq_get_freq_kernel(unsigned int cpu);
extern unsigned long cpufreq_get_freq_hardware(unsigned int cpu);
#define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu);
/* determine CPU transition latency
*
* returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds
*/
extern unsigned long cpufreq_get_transition_latency(unsigned int cpu);
/* determine hardware CPU frequency limits
*
* These may be limited further by thermal, energy or other
* considerations by cpufreq policy notifiers in the kernel.
*/
extern int cpufreq_get_hardware_limits(unsigned int cpu,
unsigned long *min,
unsigned long *max);
/* determine CPUfreq driver used
*
* Remember to call cpufreq_put_driver when no longer needed
* to avoid memory leakage, please.
*/
extern char *cpufreq_get_driver(unsigned int cpu);
extern void cpufreq_put_driver(char *ptr);
/* determine CPUfreq policy currently used
*
* Remember to call cpufreq_put_policy when no longer needed
* to avoid memory leakage, please.
*/
extern struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu);
extern void cpufreq_put_policy(struct cpufreq_policy *policy);
/* determine CPUfreq governors currently available
*
* may be modified by modprobe'ing or rmmod'ing other governors. Please
* free allocated memory by calling cpufreq_put_available_governors
* after use.
*/
extern struct cpufreq_available_governors
*cpufreq_get_available_governors(unsigned int cpu);
extern void cpufreq_put_available_governors(
struct cpufreq_available_governors *first);
/* determine CPU frequency states available
*
* Only present on _some_ ->target() cpufreq drivers. For information purposes
* only. Please free allocated memory by calling
* cpufreq_put_available_frequencies after use.
*/
extern struct cpufreq_available_frequencies
*cpufreq_get_available_frequencies(unsigned int cpu);
extern void cpufreq_put_available_frequencies(
struct cpufreq_available_frequencies *first);
/* determine affected CPUs
*
* Remember to call cpufreq_put_affected_cpus when no longer needed
* to avoid memory leakage, please.
*/
extern struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned
int cpu);
extern void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first);
/* determine related CPUs
*
* Remember to call cpufreq_put_related_cpus when no longer needed
* to avoid memory leakage, please.
*/
extern struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned
int cpu);
extern void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first);
/* determine stats for cpufreq subsystem
*
* This is not available in all kernel versions or configurations.
*/
extern struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu,
unsigned long long *total_time);
extern void cpufreq_put_stats(struct cpufreq_stats *stats);
extern unsigned long cpufreq_get_transitions(unsigned int cpu);
/* set new cpufreq policy
*
* Tries to set the passed policy as new policy as close as possible,
* but results may differ depending e.g. on governors being available.
*/
extern int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy);
/* modify a policy by only changing min/max freq or governor
*
* Does not check whether result is what was intended.
*/
extern int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq);
extern int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq);
extern int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
/* set a specific frequency
*
* Does only work if userspace governor can be used and no external
* interference (other calls to this function or to set/modify_policy)
* occurs. Also does not work on ->range() cpufreq drivers.
*/
extern int cpufreq_set_frequency(unsigned int cpu,
unsigned long target_frequency);
#ifdef __cplusplus
}
#endif
#endif /* _CPUFREQ_H */