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