2 * Copyright (c) 2005-2007 Nate Lawson (SDG)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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9 * notice, this list of conditions and the following disclaimer.
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12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/eventhandler.h>
38 #define CPU_IVAR_PCPU 1
39 #define CPU_IVAR_NOMINAL_MHZ 2
41 static __inline struct pcpu *cpu_get_pcpu(device_t dev)
44 BUS_READ_IVAR(device_get_parent(dev), dev, CPU_IVAR_PCPU, &v);
45 return ((struct pcpu *)v);
48 static __inline int32_t cpu_get_nominal_mhz(device_t dev)
51 if (BUS_READ_IVAR(device_get_parent(dev), dev,
52 CPU_IVAR_NOMINAL_MHZ, &v) != 0)
58 * CPU frequency control interface.
61 /* Each driver's CPU frequency setting is exported in this format. */
63 int freq; /* CPU clock in Mhz or 100ths of a percent. */
64 int volts; /* Voltage in mV. */
65 int power; /* Power consumed in mW. */
66 int lat; /* Transition latency in us. */
67 device_t dev; /* Driver providing this setting. */
68 int spec[4];/* Driver-specific storage for non-standard info. */
71 /* Maximum number of settings a given driver can have. */
72 #define MAX_SETTINGS 24
74 /* A combination of settings is a level. */
76 struct cf_setting total_set;
77 struct cf_setting abs_set;
78 struct cf_setting rel_set[MAX_SETTINGS];
80 TAILQ_ENTRY(cf_level) link;
83 TAILQ_HEAD(cf_level_lst, cf_level);
85 /* Drivers should set all unknown values to this. */
86 #define CPUFREQ_VAL_UNKNOWN (-1)
89 * Every driver offers a type of CPU control. Absolute levels are mutually
90 * exclusive while relative levels modify the current absolute level. There
91 * may be multiple absolute and relative drivers available on a given
94 * For example, consider a system with two absolute drivers that provide
95 * frequency settings of 100, 200 and 300, 400 and a relative driver that
96 * provides settings of 50%, 100%. The cpufreq core would export frequency
97 * levels of 50, 100, 150, 200, 300, 400.
99 * The "info only" flag signifies that settings returned by
100 * CPUFREQ_DRV_SETTINGS cannot be passed to the CPUFREQ_DRV_SET method and
101 * are only informational. This is for some drivers that can return
102 * information about settings but rely on another machine-dependent driver
103 * for actually performing the frequency transition (e.g., ACPI performance
104 * states of type "functional fixed hardware.")
106 #define CPUFREQ_TYPE_MASK 0xffff
107 #define CPUFREQ_TYPE_RELATIVE (1<<0)
108 #define CPUFREQ_TYPE_ABSOLUTE (1<<1)
109 #define CPUFREQ_FLAG_INFO_ONLY (1<<16)
112 * When setting a level, the caller indicates the priority of this request.
113 * Priorities determine, among other things, whether a level can be
114 * overridden by other callers. For example, if the user sets a level but
115 * the system thermal driver needs to override it for emergency cooling,
116 * the driver would use a higher priority. Once the event has passed, the
117 * driver would call cpufreq to resume any previous level.
119 #define CPUFREQ_PRIO_HIGHEST 1000000
120 #define CPUFREQ_PRIO_KERN 1000
121 #define CPUFREQ_PRIO_USER 100
122 #define CPUFREQ_PRIO_LOWEST 0
125 * Register and unregister a driver with the cpufreq core. Once a driver
126 * is registered, it must support calls to its CPUFREQ_GET, CPUFREQ_GET_LEVEL,
127 * and CPUFREQ_SET methods. It must also unregister before returning from
128 * its DEVICE_DETACH method.
130 int cpufreq_register(device_t dev);
131 int cpufreq_unregister(device_t dev);
134 * Notify the cpufreq core that the number of or values for settings have
137 int cpufreq_settings_changed(device_t dev);
140 * Eventhandlers that are called before and after a change in frequency.
141 * The new level and the result of the change (0 is success) is passed in.
142 * If the driver wishes to revoke the change from cpufreq_pre_change, it
143 * stores a non-zero error code in the result parameter and the change will
144 * not be made. If the post-change eventhandler gets a non-zero result,
145 * no change was made and the previous level remains in effect. If a change
146 * is revoked, the post-change eventhandler is still called with the error
147 * value supplied by the revoking driver. This gives listeners who cached
148 * some data in preparation for a level change a chance to clean up.
150 typedef void (*cpufreq_pre_notify_fn)(void *, const struct cf_level *, int *);
151 typedef void (*cpufreq_post_notify_fn)(void *, const struct cf_level *, int);
152 EVENTHANDLER_DECLARE(cpufreq_pre_change, cpufreq_pre_notify_fn);
153 EVENTHANDLER_DECLARE(cpufreq_post_change, cpufreq_post_notify_fn);
156 * Eventhandler called when the available list of levels changed.
157 * The unit number of the device (i.e. "cpufreq0") whose levels changed
158 * is provided so the listener can retrieve the new list of levels.
160 typedef void (*cpufreq_levels_notify_fn)(void *, int);
161 EVENTHANDLER_DECLARE(cpufreq_levels_changed, cpufreq_levels_notify_fn);
163 /* Allow values to be +/- a bit since sometimes we have to estimate. */
164 #define CPUFREQ_CMP(x, y) (abs((x) - (y)) < 25)
167 * Machine-dependent functions.
170 /* Estimate the current clock rate for the given CPU id. */
171 int cpu_est_clockrate(int cpu_id, uint64_t *rate);
173 #endif /* !_SYS_CPU_H_ */