FreeBSD/Linux Kernel Cross Reference
sys/sys/cpu.h
1 /*-
2 * Copyright (c) 2005-2007 Nate Lawson (SDG)
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/sys/cpu.h,v 1.4 2007/03/26 18:03:28 njl Exp $
27 */
28
29 #ifndef _SYS_CPU_H_
30 #define _SYS_CPU_H_
31
32 #include <sys/eventhandler.h>
33
34 /*
35 * CPU device support.
36 */
37
38 #define CPU_IVAR_PCPU 1
39
40 static __inline struct pcpu *cpu_get_pcpu(device_t dev)
41 {
42 uintptr_t v = 0;
43 BUS_READ_IVAR(device_get_parent(dev), dev, CPU_IVAR_PCPU, &v);
44 return ((struct pcpu *)v);
45 }
46
47 /*
48 * CPU frequency control interface.
49 */
50
51 /* Each driver's CPU frequency setting is exported in this format. */
52 struct cf_setting {
53 int freq; /* CPU clock in Mhz or 100ths of a percent. */
54 int volts; /* Voltage in mV. */
55 int power; /* Power consumed in mW. */
56 int lat; /* Transition latency in us. */
57 device_t dev; /* Driver providing this setting. */
58 int spec[4];/* Driver-specific storage for non-standard info. */
59 };
60
61 /* Maximum number of settings a given driver can have. */
62 #define MAX_SETTINGS 24
63
64 /* A combination of settings is a level. */
65 struct cf_level {
66 struct cf_setting total_set;
67 struct cf_setting abs_set;
68 struct cf_setting rel_set[MAX_SETTINGS];
69 int rel_count;
70 TAILQ_ENTRY(cf_level) link;
71 };
72
73 TAILQ_HEAD(cf_level_lst, cf_level);
74
75 /* Drivers should set all unknown values to this. */
76 #define CPUFREQ_VAL_UNKNOWN (-1)
77
78 /*
79 * Every driver offers a type of CPU control. Absolute levels are mutually
80 * exclusive while relative levels modify the current absolute level. There
81 * may be multiple absolute and relative drivers available on a given
82 * system.
83 *
84 * For example, consider a system with two absolute drivers that provide
85 * frequency settings of 100, 200 and 300, 400 and a relative driver that
86 * provides settings of 50%, 100%. The cpufreq core would export frequency
87 * levels of 50, 100, 150, 200, 300, 400.
88 *
89 * The "info only" flag signifies that settings returned by
90 * CPUFREQ_DRV_SETTINGS cannot be passed to the CPUFREQ_DRV_SET method and
91 * are only informational. This is for some drivers that can return
92 * information about settings but rely on another machine-dependent driver
93 * for actually performing the frequency transition (e.g., ACPI performance
94 * states of type "functional fixed hardware.")
95 */
96 #define CPUFREQ_TYPE_MASK 0xffff
97 #define CPUFREQ_TYPE_RELATIVE (1<<0)
98 #define CPUFREQ_TYPE_ABSOLUTE (1<<1)
99 #define CPUFREQ_FLAG_INFO_ONLY (1<<16)
100
101 /*
102 * When setting a level, the caller indicates the priority of this request.
103 * Priorities determine, among other things, whether a level can be
104 * overridden by other callers. For example, if the user sets a level but
105 * the system thermal driver needs to override it for emergency cooling,
106 * the driver would use a higher priority. Once the event has passed, the
107 * driver would call cpufreq to resume any previous level.
108 */
109 #define CPUFREQ_PRIO_HIGHEST 1000000
110 #define CPUFREQ_PRIO_KERN 1000
111 #define CPUFREQ_PRIO_USER 100
112 #define CPUFREQ_PRIO_LOWEST 0
113
114 /*
115 * Register and unregister a driver with the cpufreq core. Once a driver
116 * is registered, it must support calls to its CPUFREQ_GET, CPUFREQ_GET_LEVEL,
117 * and CPUFREQ_SET methods. It must also unregister before returning from
118 * its DEVICE_DETACH method.
119 */
120 int cpufreq_register(device_t dev);
121 int cpufreq_unregister(device_t dev);
122
123 /*
124 * Notify the cpufreq core that the number of or values for settings have
125 * changed.
126 */
127 int cpufreq_settings_changed(device_t dev);
128
129 /*
130 * Eventhandlers that are called before and after a change in frequency.
131 * The new level and the result of the change (0 is success) is passed in.
132 * If the driver wishes to revoke the change from cpufreq_pre_change, it
133 * stores a non-zero error code in the result parameter and the change will
134 * not be made. If the post-change eventhandler gets a non-zero result,
135 * no change was made and the previous level remains in effect. If a change
136 * is revoked, the post-change eventhandler is still called with the error
137 * value supplied by the revoking driver. This gives listeners who cached
138 * some data in preparation for a level change a chance to clean up.
139 */
140 typedef void (*cpufreq_pre_notify_fn)(void *, const struct cf_level *, int *);
141 typedef void (*cpufreq_post_notify_fn)(void *, const struct cf_level *, int);
142 EVENTHANDLER_DECLARE(cpufreq_pre_change, cpufreq_pre_notify_fn);
143 EVENTHANDLER_DECLARE(cpufreq_post_change, cpufreq_post_notify_fn);
144
145 /*
146 * Eventhandler called when the available list of levels changed.
147 * The unit number of the device (i.e. "cpufreq0") whose levels changed
148 * is provided so the listener can retrieve the new list of levels.
149 */
150 typedef void (*cpufreq_levels_notify_fn)(void *, int);
151 EVENTHANDLER_DECLARE(cpufreq_levels_changed, cpufreq_levels_notify_fn);
152
153 /* Allow values to be +/- a bit since sometimes we have to estimate. */
154 #define CPUFREQ_CMP(x, y) (abs((x) - (y)) < 25)
155
156 /*
157 * Machine-dependent functions.
158 */
159
160 /* Estimate the current clock rate for the given CPU id. */
161 int cpu_est_clockrate(int cpu_id, uint64_t *rate);
162
163 #endif /* !_SYS_CPU_H_ */
164
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