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