351 lines
9.6 KiB
C++
351 lines
9.6 KiB
C++
/*
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* \brief Connection to timer service and timeout scheduler
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* \author Norman Feske
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* \date 2008-08-22
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*/
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/*
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* Copyright (C) 2008-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__TIMER_SESSION__CONNECTION_H_
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#define _INCLUDE__TIMER_SESSION__CONNECTION_H_
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/* Genode includes */
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#include <timer_session/client.h>
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#include <base/connection.h>
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#include <util/reconstructible.h>
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#include <base/entrypoint.h>
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#include <timer/timeout.h>
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#include <trace/timestamp.h>
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namespace Timer
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{
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class Connection;
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template <typename> class Periodic_timeout;
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template <typename> class One_shot_timeout;
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}
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/**
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* Periodic timeout that is linked to a custom handler, scheduled when constructed
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*/
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template <typename HANDLER>
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struct Timer::Periodic_timeout : private Genode::Noncopyable
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{
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private:
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using Duration = Genode::Duration;
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using Timeout = Genode::Timeout;
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using Timeout_scheduler = Genode::Timeout_scheduler;
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using Microseconds = Genode::Microseconds;
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typedef void (HANDLER::*Handler_method)(Duration);
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Timeout _timeout;
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struct Handler : Timeout::Handler
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{
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HANDLER &object;
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Handler_method const method;
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Handler(HANDLER &object, Handler_method method)
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: object(object), method(method) { }
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/**********************
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** Timeout::Handler **
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**********************/
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void handle_timeout(Duration curr_time) override {
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(object.*method)(curr_time); }
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} _handler;
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public:
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Periodic_timeout(Timeout_scheduler &timeout_scheduler,
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HANDLER &object,
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Handler_method method,
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Microseconds duration)
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:
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_timeout(timeout_scheduler), _handler(object, method)
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{
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_timeout.schedule_periodic(duration, _handler);
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}
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};
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/**
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* One-shot timeout that is linked to a custom handler, scheduled manually
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*/
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template <typename HANDLER>
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class Timer::One_shot_timeout : private Genode::Noncopyable
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{
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private:
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using Duration = Genode::Duration;
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using Timeout = Genode::Timeout;
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using Timeout_scheduler = Genode::Timeout_scheduler;
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using Microseconds = Genode::Microseconds;
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typedef void (HANDLER::*Handler_method)(Duration);
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Timeout _timeout;
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struct Handler : Timeout::Handler
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{
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HANDLER &object;
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Handler_method const method;
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Handler(HANDLER &object, Handler_method method)
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: object(object), method(method) { }
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/**********************
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** Timeout::Handler **
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**********************/
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void handle_timeout(Duration curr_time) override {
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(object.*method)(curr_time); }
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} _handler;
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public:
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One_shot_timeout(Timeout_scheduler &timeout_scheduler,
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HANDLER &object,
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Handler_method method)
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: _timeout(timeout_scheduler), _handler(object, method) { }
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void schedule(Microseconds duration) {
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_timeout.schedule_one_shot(duration, _handler); }
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void discard() { _timeout.discard(); }
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bool scheduled() { return _timeout.scheduled(); }
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};
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/**
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* Connection to timer service and timeout scheduler
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*
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* Multiplexes a timer session amongst different timeouts.
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*/
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class Timer::Connection : public Genode::Connection<Session>,
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public Session_client,
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private Genode::Time_source,
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public Genode::Timeout_scheduler
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{
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private:
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using Timeout = Genode::Timeout;
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using Timeout_handler = Genode::Time_source::Timeout_handler;
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using Timestamp = Genode::Trace::Timestamp;
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using Duration = Genode::Duration;
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using Lock = Genode::Lock;
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using Microseconds = Genode::Microseconds;
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using Milliseconds = Genode::Milliseconds;
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using Entrypoint = Genode::Entrypoint;
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/*
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* Noncopyable
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*/
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Connection(Connection const &);
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Connection &operator = (Connection const &);
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/*
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* The mode determines which interface of the timer connection is
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* enabled. Initially, a timer connection is in LEGACY mode. When in
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* MODERN mode, a call to the LEGACY interface causes an exception.
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* When in LEGACY mode, a call to the MODERN interface causes a switch
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* to the MODERN mode. The LEGACY interface is deprecated. Please
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* prefer using the MODERN interface.
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*
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* LEGACY = Timer Session interface, blocking calls usleep and msleep
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* MODERN = more precise curr_time, non-blocking and multiplexed
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* handling with Periodic_timeout resp. One_shot_timeout
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*/
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enum Mode { LEGACY, MODERN };
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Mode _mode { LEGACY };
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Genode::Lock _lock { };
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Genode::Signal_receiver _sig_rec { };
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Genode::Signal_context _default_sigh_ctx { };
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Genode::Signal_context_capability
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_default_sigh_cap = _sig_rec.manage(&_default_sigh_ctx);
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Genode::Signal_context_capability _custom_sigh_cap { };
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void _enable_modern_mode();
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void _sigh(Signal_context_capability sigh)
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{
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Session_client::sigh(sigh);
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}
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/*************************
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** Time_source helpers **
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*************************/
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enum { MIN_TIMEOUT_US = 5000 };
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enum { REAL_TIME_UPDATE_PERIOD_US = 500000 };
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enum { MAX_INTERPOLATION_QUALITY = 3 };
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enum { MAX_REMOTE_TIME_LATENCY_US = 500 };
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enum { MAX_REMOTE_TIME_TRIALS = 5 };
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enum { NR_OF_INITIAL_CALIBRATIONS = 3 * MAX_INTERPOLATION_QUALITY };
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enum { MIN_FACTOR_LOG2 = 8 };
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Genode::Io_signal_handler<Connection> _signal_handler;
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Timeout_handler *_handler { nullptr };
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Lock _real_time_lock { Lock::UNLOCKED };
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unsigned long _us { elapsed_us() };
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Timestamp _ts { _timestamp() };
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Duration _real_time { Microseconds(_us) };
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Duration _interpolated_time { _real_time };
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unsigned _interpolation_quality { 0 };
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unsigned long _us_to_ts_factor { 1UL };
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unsigned _us_to_ts_factor_shift { 0 };
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Timestamp _timestamp();
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void _update_interpolation_quality(unsigned long min_factor,
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unsigned long max_factor);
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unsigned long _ts_to_us_ratio(Timestamp ts,
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unsigned long us,
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unsigned shift);
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void _update_real_time();
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Duration _update_interpolated_time(Duration &interpolated_time);
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void _handle_timeout();
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/*****************
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** Time_source **
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*****************/
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void schedule_timeout(Microseconds duration, Timeout_handler &handler) override;
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Microseconds max_timeout() const override { return Microseconds(REAL_TIME_UPDATE_PERIOD_US); }
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/*******************************
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** Timeout_scheduler helpers **
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*******************************/
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Genode::Alarm_timeout_scheduler _scheduler { *this };
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/***********************
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** Timeout_scheduler **
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***********************/
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void _schedule_one_shot(Timeout &timeout, Microseconds duration) override;
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void _schedule_periodic(Timeout &timeout, Microseconds duration) override;
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void _discard(Timeout &timeout) override;
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public:
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struct Cannot_use_both_legacy_and_modern_interface : Genode::Exception { };
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/**
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* Constructor
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*/
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Connection(Genode::Env &env, char const *label = "");
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/**
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* Constructor
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*
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* \noapi
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* \deprecated Use the constructor with 'Env &' as first
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* argument instead
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*/
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Connection() __attribute__((deprecated));
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~Connection() { _sig_rec.dissolve(&_default_sigh_ctx); }
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/*
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* Intercept 'sigh' to keep track of customized signal handlers
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*
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* \noapi
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* \deprecated Use One_shot_timeout (or Periodic_timeout) instead
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*/
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void sigh(Signal_context_capability sigh) override
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{
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if (_mode == MODERN) {
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throw Cannot_use_both_legacy_and_modern_interface();
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}
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_custom_sigh_cap = sigh;
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Session_client::sigh(_custom_sigh_cap);
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}
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/*
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* Block for a time span of 'us' microseconds
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*
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* \noapi
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* \deprecated Use One_shot_timeout (or Periodic_timeout) instead
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*/
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void usleep(unsigned us) override
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{
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if (_mode == MODERN) {
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throw Cannot_use_both_legacy_and_modern_interface();
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}
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/*
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* Omit the interaction with the timer driver for the corner case
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* of not sleeping at all. This corner case may be triggered when
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* polling is combined with sleeping (as some device drivers do).
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* If we passed the sleep operation to the timer driver, the
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* timer would apply its policy about a minimum sleep time to
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* the sleep operation, which is not desired when polling.
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*/
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if (us == 0)
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return;
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/* serialize sleep calls issued by different threads */
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Genode::Lock::Guard guard(_lock);
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/* temporarily install to the default signal handler */
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if (_custom_sigh_cap.valid())
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Session_client::sigh(_default_sigh_cap);
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/* trigger timeout at default signal handler */
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trigger_once(us);
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_sig_rec.wait_for_signal();
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/* revert custom signal handler if registered */
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if (_custom_sigh_cap.valid())
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Session_client::sigh(_custom_sigh_cap);
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}
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/*
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* Block for a time span of 'ms' milliseconds
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*
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* \noapi
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* \deprecated Use One_shot_timeout (or Periodic_timeout) instead
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*/
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void msleep(unsigned ms) override
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{
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if (_mode == MODERN) {
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throw Cannot_use_both_legacy_and_modern_interface();
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}
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usleep(1000*ms);
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}
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/***********************************
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** Timeout_scheduler/Time_source **
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***********************************/
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Duration curr_time() override;
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};
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#endif /* _INCLUDE__TIMER_SESSION__CONNECTION_H_ */
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