Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-for-5.2-pull-reques...
[qemu.git] / include / hw / clock.h
1 /*
2 * Hardware Clocks
3 *
4 * Copyright GreenSocs 2016-2020
5 *
6 * Authors:
7 * Frederic Konrad
8 * Damien Hedde
9 *
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.
12 */
13
14 #ifndef QEMU_HW_CLOCK_H
15 #define QEMU_HW_CLOCK_H
16
17 #include "qom/object.h"
18 #include "qemu/queue.h"
19
20 #define TYPE_CLOCK "clock"
21 #define CLOCK(obj) OBJECT_CHECK(Clock, (obj), TYPE_CLOCK)
22
23 typedef void ClockCallback(void *opaque);
24
25 /*
26 * clock store a value representing the clock's period in 2^-32ns unit.
27 * It can represent:
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
34 */
35 #define CLOCK_PERIOD_1SEC (1000000000llu << 32)
36
37 /*
38 * macro helpers to convert to hertz / nanosecond
39 */
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)
44
45 /**
46 * Clock:
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
55 */
56
57 typedef struct Clock Clock;
58
59 struct Clock {
60 /*< private >*/
61 Object parent_obj;
62
63 /* all fields are private and should not be modified directly */
64
65 /* fields */
66 uint64_t period;
67 char *canonical_path;
68 ClockCallback *callback;
69 void *callback_opaque;
70
71 /* Clocks are organized in a clock tree */
72 Clock *source;
73 QLIST_HEAD(, Clock) children;
74 QLIST_ENTRY(Clock) sibling;
75 };
76
77 /*
78 * vmstate description entry to be added in device vmsd.
79 */
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)
85
86 /**
87 * clock_setup_canonical_path:
88 * @clk: clock
89 *
90 * compute the canonical path of the clock (used by log messages)
91 */
92 void clock_setup_canonical_path(Clock *clk);
93
94 /**
95 * clock_set_callback:
96 * @clk: the clock to register the callback into
97 * @cb: the callback function
98 * @opaque: the argument to the callback
99 *
100 * Register a callback called on every clock update.
101 */
102 void clock_set_callback(Clock *clk, ClockCallback *cb, void *opaque);
103
104 /**
105 * clock_clear_callback:
106 * @clk: the clock to delete the callback from
107 *
108 * Unregister the callback registered with clock_set_callback.
109 */
110 void clock_clear_callback(Clock *clk);
111
112 /**
113 * clock_set_source:
114 * @clk: the clock.
115 * @src: the source clock
116 *
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
119 * called.
120 * Further @src update will be propagated to @clk and its subtree.
121 */
122 void clock_set_source(Clock *clk, Clock *src);
123
124 /**
125 * clock_set:
126 * @clk: the clock to initialize.
127 * @value: the clock's value, 0 means unclocked
128 *
129 * Set the local cached period value of @clk to @value.
130 *
131 * @return: true if the clock is changed.
132 */
133 bool clock_set(Clock *clk, uint64_t value);
134
135 static inline bool clock_set_hz(Clock *clk, unsigned hz)
136 {
137 return clock_set(clk, CLOCK_PERIOD_FROM_HZ(hz));
138 }
139
140 static inline bool clock_set_ns(Clock *clk, unsigned ns)
141 {
142 return clock_set(clk, CLOCK_PERIOD_FROM_NS(ns));
143 }
144
145 /**
146 * clock_propagate:
147 * @clk: the clock
148 *
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
153 * or migration.
154 */
155 void clock_propagate(Clock *clk);
156
157 /**
158 * clock_update:
159 * @clk: the clock to update.
160 * @value: the new clock's value, 0 means unclocked
161 *
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().
165 */
166 static inline void clock_update(Clock *clk, uint64_t value)
167 {
168 if (clock_set(clk, value)) {
169 clock_propagate(clk);
170 }
171 }
172
173 static inline void clock_update_hz(Clock *clk, unsigned hz)
174 {
175 clock_update(clk, CLOCK_PERIOD_FROM_HZ(hz));
176 }
177
178 static inline void clock_update_ns(Clock *clk, unsigned ns)
179 {
180 clock_update(clk, CLOCK_PERIOD_FROM_NS(ns));
181 }
182
183 /**
184 * clock_get:
185 * @clk: the clk to fetch the clock
186 *
187 * @return: the current period.
188 */
189 static inline uint64_t clock_get(const Clock *clk)
190 {
191 return clk->period;
192 }
193
194 static inline unsigned clock_get_hz(Clock *clk)
195 {
196 return CLOCK_PERIOD_TO_HZ(clock_get(clk));
197 }
198
199 static inline unsigned clock_get_ns(Clock *clk)
200 {
201 return CLOCK_PERIOD_TO_NS(clock_get(clk));
202 }
203
204 /**
205 * clock_is_enabled:
206 * @clk: a clock
207 *
208 * @return: true if the clock is running.
209 */
210 static inline bool clock_is_enabled(const Clock *clk)
211 {
212 return clock_get(clk) != 0;
213 }
214
215 #endif /* QEMU_HW_CLOCK_H */