4 * Copyright GreenSocs 2016-2020
10 * This work is licensed under the terms of the GNU GPL, version 2 or later.
11 * See the COPYING file in the top-level directory.
14 #ifndef QEMU_HW_CLOCK_H
15 #define QEMU_HW_CLOCK_H
17 #include "qom/object.h"
18 #include "qemu/queue.h"
20 #define TYPE_CLOCK "clock"
21 #define CLOCK(obj) OBJECT_CHECK(Clock, (obj), TYPE_CLOCK)
23 typedef void ClockCallback(void *opaque
);
26 * clock store a value representing the clock's period in 2^-32ns unit.
28 * + periods from 2^-32ns up to 4seconds
29 * + frequency from ~0.25Hz 2e10Ghz
30 * Resolution of frequency representation decreases with frequency:
31 * + at 100MHz, resolution is ~2mHz
32 * + at 1Ghz, resolution is ~0.2Hz
33 * + at 10Ghz, resolution is ~20Hz
35 #define CLOCK_PERIOD_1SEC (1000000000llu << 32)
38 * macro helpers to convert to hertz / nanosecond
40 #define CLOCK_PERIOD_FROM_NS(ns) ((ns) * (CLOCK_PERIOD_1SEC / 1000000000llu))
41 #define CLOCK_PERIOD_TO_NS(per) ((per) / (CLOCK_PERIOD_1SEC / 1000000000llu))
42 #define CLOCK_PERIOD_FROM_HZ(hz) (((hz) != 0) ? CLOCK_PERIOD_1SEC / (hz) : 0u)
43 #define CLOCK_PERIOD_TO_HZ(per) (((per) != 0) ? CLOCK_PERIOD_1SEC / (per) : 0u)
47 * @parent_obj: parent class
48 * @period: unsigned integer representing the period of the clock
49 * @canonical_path: clock path string cache (used for trace purpose)
50 * @callback: called when clock changes
51 * @callback_opaque: argument for @callback
52 * @source: source (or parent in clock tree) of the clock
53 * @children: list of clocks connected to this one (it is their source)
54 * @sibling: structure used to form a clock list
57 typedef struct Clock Clock
;
63 /* all fields are private and should not be modified directly */
68 ClockCallback
*callback
;
69 void *callback_opaque
;
71 /* Clocks are organized in a clock tree */
73 QLIST_HEAD(, Clock
) children
;
74 QLIST_ENTRY(Clock
) sibling
;
78 * vmstate description entry to be added in device vmsd.
80 extern const VMStateDescription vmstate_clock
;
81 #define VMSTATE_CLOCK(field, state) \
82 VMSTATE_CLOCK_V(field, state, 0)
83 #define VMSTATE_CLOCK_V(field, state, version) \
84 VMSTATE_STRUCT_POINTER_V(field, state, version, vmstate_clock, Clock)
87 * clock_setup_canonical_path:
90 * compute the canonical path of the clock (used by log messages)
92 void clock_setup_canonical_path(Clock
*clk
);
96 * @clk: the clock to register the callback into
97 * @cb: the callback function
98 * @opaque: the argument to the callback
100 * Register a callback called on every clock update.
102 void clock_set_callback(Clock
*clk
, ClockCallback
*cb
, void *opaque
);
105 * clock_clear_callback:
106 * @clk: the clock to delete the callback from
108 * Unregister the callback registered with clock_set_callback.
110 void clock_clear_callback(Clock
*clk
);
115 * @src: the source clock
117 * Setup @src as the clock source of @clk. The current @src period
118 * value is also copied to @clk and its subtree but no callback is
120 * Further @src update will be propagated to @clk and its subtree.
122 void clock_set_source(Clock
*clk
, Clock
*src
);
126 * @clk: the clock to initialize.
127 * @value: the clock's value, 0 means unclocked
129 * Set the local cached period value of @clk to @value.
131 * @return: true if the clock is changed.
133 bool clock_set(Clock
*clk
, uint64_t value
);
135 static inline bool clock_set_hz(Clock
*clk
, unsigned hz
)
137 return clock_set(clk
, CLOCK_PERIOD_FROM_HZ(hz
));
140 static inline bool clock_set_ns(Clock
*clk
, unsigned ns
)
142 return clock_set(clk
, CLOCK_PERIOD_FROM_NS(ns
));
149 * Propagate the clock period that has been previously configured using
150 * @clock_set(). This will update recursively all connected clocks.
151 * It is an error to call this function on a clock which has a source.
152 * Note: this function must not be called during device inititialization
155 void clock_propagate(Clock
*clk
);
159 * @clk: the clock to update.
160 * @value: the new clock's value, 0 means unclocked
162 * Update the @clk to the new @value. All connected clocks will be informed
163 * of this update. This is equivalent to call @clock_set() then
164 * @clock_propagate().
166 static inline void clock_update(Clock
*clk
, uint64_t value
)
168 if (clock_set(clk
, value
)) {
169 clock_propagate(clk
);
173 static inline void clock_update_hz(Clock
*clk
, unsigned hz
)
175 clock_update(clk
, CLOCK_PERIOD_FROM_HZ(hz
));
178 static inline void clock_update_ns(Clock
*clk
, unsigned ns
)
180 clock_update(clk
, CLOCK_PERIOD_FROM_NS(ns
));
185 * @clk: the clk to fetch the clock
187 * @return: the current period.
189 static inline uint64_t clock_get(const Clock
*clk
)
194 static inline unsigned clock_get_hz(Clock
*clk
)
196 return CLOCK_PERIOD_TO_HZ(clock_get(clk
));
199 static inline unsigned clock_get_ns(Clock
*clk
)
201 return CLOCK_PERIOD_TO_NS(clock_get(clk
));
208 * @return: true if the clock is running.
210 static inline bool clock_is_enabled(const Clock
*clk
)
212 return clock_get(clk
) != 0;
215 #endif /* QEMU_HW_CLOCK_H */