qemu-e2k/include/hw/ptimer.h

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/*
* General purpose implementation of a simple periodic countdown timer.
*
* Copyright (c) 2007 CodeSourcery.
*
* This code is licensed under the GNU LGPL.
*/
#ifndef PTIMER_H
#define PTIMER_H
#include "qemu-common.h"
#include "qemu/timer.h"
#include "migration/vmstate.h"
/* The default ptimer policy retains backward compatibility with the legacy
* timers. Custom policies are adjusting the default one. Consider providing
* a correct policy for your timer.
*
* The rough edges of the default policy:
* - Starting to run with a period = 0 emits error message and stops the
* timer without a trigger.
*
* - Setting period to 0 of the running timer emits error message and
* stops the timer without a trigger.
*
* - Starting to run with counter = 0 or setting it to "0" while timer
* is running causes a trigger and reloads counter with a limit value.
* If limit = 0, ptimer emits error message and stops the timer.
*
* - Counter value of the running timer is one less than the actual value.
*
* - Changing period/frequency of the running timer loses time elapsed
* since the last period, effectively restarting the timer with a
* counter = counter value at the moment of change (.i.e. one less).
*/
#define PTIMER_POLICY_DEFAULT 0
/* Periodic timer counter stays with "0" for a one period before wrapping
* around. */
#define PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD (1 << 0)
/* Running periodic timer that has counter = limit = 0 would continuously
* re-trigger every period. */
#define PTIMER_POLICY_CONTINUOUS_TRIGGER (1 << 1)
/* Starting to run with/setting counter to "0" won't trigger immediately,
* but after a one period for both oneshot and periodic modes. */
#define PTIMER_POLICY_NO_IMMEDIATE_TRIGGER (1 << 2)
/* Starting to run with/setting counter to "0" won't re-load counter
* immediately, but after a one period. */
#define PTIMER_POLICY_NO_IMMEDIATE_RELOAD (1 << 3)
/* Make counter value of the running timer represent the actual value and
* not the one less. */
#define PTIMER_POLICY_NO_COUNTER_ROUND_DOWN (1 << 4)
/* ptimer.c */
typedef struct ptimer_state ptimer_state;
typedef void (*ptimer_cb)(void *opaque);
ptimer_state *ptimer_init(QEMUBH *bh, uint8_t policy_mask);
void ptimer_set_period(ptimer_state *s, int64_t period);
void ptimer_set_freq(ptimer_state *s, uint32_t freq);
uint64_t ptimer_get_limit(ptimer_state *s);
void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload);
uint64_t ptimer_get_count(ptimer_state *s);
void ptimer_set_count(ptimer_state *s, uint64_t count);
void ptimer_run(ptimer_state *s, int oneshot);
void ptimer_stop(ptimer_state *s);
extern const VMStateDescription vmstate_ptimer;
#define VMSTATE_PTIMER(_field, _state) \
VMSTATE_STRUCT_POINTER_V(_field, _state, 1, vmstate_ptimer, ptimer_state)
#define VMSTATE_PTIMER_ARRAY(_f, _s, _n) \
VMSTATE_ARRAY_OF_POINTER_TO_STRUCT(_f, _s, _n, 0, \
vmstate_ptimer, ptimer_state)
#endif