92 lines
2.4 KiB
C++
92 lines
2.4 KiB
C++
/*
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* \brief Connection to timer service
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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) 2008-2013 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 General Public License version 2.
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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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#include <timer_session/client.h>
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#include <base/connection.h>
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namespace Timer { class Connection; }
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class Timer::Connection : public Genode::Connection<Session>, public Session_client
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{
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private:
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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 _default_sigh_cap;
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Genode::Signal_context_capability _custom_sigh_cap;
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public:
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Connection()
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:
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Genode::Connection<Session>(session("ram_quota=8K")),
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Session_client(cap()),
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_default_sigh_cap(_sig_rec.manage(&_default_sigh_ctx))
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{
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/* register default signal handler */
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Session_client::sigh(_default_sigh_cap);
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}
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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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void sigh(Signal_context_capability sigh)
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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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void usleep(unsigned us)
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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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void msleep(unsigned ms)
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{
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usleep(1000*ms);
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}
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};
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#endif /* _INCLUDE__TIMER_SESSION__CONNECTION_H_ */
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