Avoid propagating the clock change when the clock does not change. Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20200806123858.30058-4-f4bug@amsat.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
216 lines
5.4 KiB
C
216 lines
5.4 KiB
C
/*
|
|
* Hardware Clocks
|
|
*
|
|
* Copyright GreenSocs 2016-2020
|
|
*
|
|
* Authors:
|
|
* Frederic Konrad
|
|
* Damien Hedde
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
#ifndef QEMU_HW_CLOCK_H
|
|
#define QEMU_HW_CLOCK_H
|
|
|
|
#include "qom/object.h"
|
|
#include "qemu/queue.h"
|
|
|
|
#define TYPE_CLOCK "clock"
|
|
#define CLOCK(obj) OBJECT_CHECK(Clock, (obj), TYPE_CLOCK)
|
|
|
|
typedef void ClockCallback(void *opaque);
|
|
|
|
/*
|
|
* clock store a value representing the clock's period in 2^-32ns unit.
|
|
* It can represent:
|
|
* + periods from 2^-32ns up to 4seconds
|
|
* + frequency from ~0.25Hz 2e10Ghz
|
|
* Resolution of frequency representation decreases with frequency:
|
|
* + at 100MHz, resolution is ~2mHz
|
|
* + at 1Ghz, resolution is ~0.2Hz
|
|
* + at 10Ghz, resolution is ~20Hz
|
|
*/
|
|
#define CLOCK_PERIOD_1SEC (1000000000llu << 32)
|
|
|
|
/*
|
|
* macro helpers to convert to hertz / nanosecond
|
|
*/
|
|
#define CLOCK_PERIOD_FROM_NS(ns) ((ns) * (CLOCK_PERIOD_1SEC / 1000000000llu))
|
|
#define CLOCK_PERIOD_TO_NS(per) ((per) / (CLOCK_PERIOD_1SEC / 1000000000llu))
|
|
#define CLOCK_PERIOD_FROM_HZ(hz) (((hz) != 0) ? CLOCK_PERIOD_1SEC / (hz) : 0u)
|
|
#define CLOCK_PERIOD_TO_HZ(per) (((per) != 0) ? CLOCK_PERIOD_1SEC / (per) : 0u)
|
|
|
|
/**
|
|
* Clock:
|
|
* @parent_obj: parent class
|
|
* @period: unsigned integer representing the period of the clock
|
|
* @canonical_path: clock path string cache (used for trace purpose)
|
|
* @callback: called when clock changes
|
|
* @callback_opaque: argument for @callback
|
|
* @source: source (or parent in clock tree) of the clock
|
|
* @children: list of clocks connected to this one (it is their source)
|
|
* @sibling: structure used to form a clock list
|
|
*/
|
|
|
|
typedef struct Clock Clock;
|
|
|
|
struct Clock {
|
|
/*< private >*/
|
|
Object parent_obj;
|
|
|
|
/* all fields are private and should not be modified directly */
|
|
|
|
/* fields */
|
|
uint64_t period;
|
|
char *canonical_path;
|
|
ClockCallback *callback;
|
|
void *callback_opaque;
|
|
|
|
/* Clocks are organized in a clock tree */
|
|
Clock *source;
|
|
QLIST_HEAD(, Clock) children;
|
|
QLIST_ENTRY(Clock) sibling;
|
|
};
|
|
|
|
/*
|
|
* vmstate description entry to be added in device vmsd.
|
|
*/
|
|
extern const VMStateDescription vmstate_clock;
|
|
#define VMSTATE_CLOCK(field, state) \
|
|
VMSTATE_CLOCK_V(field, state, 0)
|
|
#define VMSTATE_CLOCK_V(field, state, version) \
|
|
VMSTATE_STRUCT_POINTER_V(field, state, version, vmstate_clock, Clock)
|
|
|
|
/**
|
|
* clock_setup_canonical_path:
|
|
* @clk: clock
|
|
*
|
|
* compute the canonical path of the clock (used by log messages)
|
|
*/
|
|
void clock_setup_canonical_path(Clock *clk);
|
|
|
|
/**
|
|
* clock_set_callback:
|
|
* @clk: the clock to register the callback into
|
|
* @cb: the callback function
|
|
* @opaque: the argument to the callback
|
|
*
|
|
* Register a callback called on every clock update.
|
|
*/
|
|
void clock_set_callback(Clock *clk, ClockCallback *cb, void *opaque);
|
|
|
|
/**
|
|
* clock_clear_callback:
|
|
* @clk: the clock to delete the callback from
|
|
*
|
|
* Unregister the callback registered with clock_set_callback.
|
|
*/
|
|
void clock_clear_callback(Clock *clk);
|
|
|
|
/**
|
|
* clock_set_source:
|
|
* @clk: the clock.
|
|
* @src: the source clock
|
|
*
|
|
* Setup @src as the clock source of @clk. The current @src period
|
|
* value is also copied to @clk and its subtree but no callback is
|
|
* called.
|
|
* Further @src update will be propagated to @clk and its subtree.
|
|
*/
|
|
void clock_set_source(Clock *clk, Clock *src);
|
|
|
|
/**
|
|
* clock_set:
|
|
* @clk: the clock to initialize.
|
|
* @value: the clock's value, 0 means unclocked
|
|
*
|
|
* Set the local cached period value of @clk to @value.
|
|
*
|
|
* @return: true if the clock is changed.
|
|
*/
|
|
bool clock_set(Clock *clk, uint64_t value);
|
|
|
|
static inline bool clock_set_hz(Clock *clk, unsigned hz)
|
|
{
|
|
return clock_set(clk, CLOCK_PERIOD_FROM_HZ(hz));
|
|
}
|
|
|
|
static inline bool clock_set_ns(Clock *clk, unsigned ns)
|
|
{
|
|
return clock_set(clk, CLOCK_PERIOD_FROM_NS(ns));
|
|
}
|
|
|
|
/**
|
|
* clock_propagate:
|
|
* @clk: the clock
|
|
*
|
|
* Propagate the clock period that has been previously configured using
|
|
* @clock_set(). This will update recursively all connected clocks.
|
|
* It is an error to call this function on a clock which has a source.
|
|
* Note: this function must not be called during device inititialization
|
|
* or migration.
|
|
*/
|
|
void clock_propagate(Clock *clk);
|
|
|
|
/**
|
|
* clock_update:
|
|
* @clk: the clock to update.
|
|
* @value: the new clock's value, 0 means unclocked
|
|
*
|
|
* Update the @clk to the new @value. All connected clocks will be informed
|
|
* of this update. This is equivalent to call @clock_set() then
|
|
* @clock_propagate().
|
|
*/
|
|
static inline void clock_update(Clock *clk, uint64_t value)
|
|
{
|
|
if (clock_set(clk, value)) {
|
|
clock_propagate(clk);
|
|
}
|
|
}
|
|
|
|
static inline void clock_update_hz(Clock *clk, unsigned hz)
|
|
{
|
|
clock_update(clk, CLOCK_PERIOD_FROM_HZ(hz));
|
|
}
|
|
|
|
static inline void clock_update_ns(Clock *clk, unsigned ns)
|
|
{
|
|
clock_update(clk, CLOCK_PERIOD_FROM_NS(ns));
|
|
}
|
|
|
|
/**
|
|
* clock_get:
|
|
* @clk: the clk to fetch the clock
|
|
*
|
|
* @return: the current period.
|
|
*/
|
|
static inline uint64_t clock_get(const Clock *clk)
|
|
{
|
|
return clk->period;
|
|
}
|
|
|
|
static inline unsigned clock_get_hz(Clock *clk)
|
|
{
|
|
return CLOCK_PERIOD_TO_HZ(clock_get(clk));
|
|
}
|
|
|
|
static inline unsigned clock_get_ns(Clock *clk)
|
|
{
|
|
return CLOCK_PERIOD_TO_NS(clock_get(clk));
|
|
}
|
|
|
|
/**
|
|
* clock_is_enabled:
|
|
* @clk: a clock
|
|
*
|
|
* @return: true if the clock is running.
|
|
*/
|
|
static inline bool clock_is_enabled(const Clock *clk)
|
|
{
|
|
return clock_get(clk) != 0;
|
|
}
|
|
|
|
#endif /* QEMU_HW_CLOCK_H */
|