83 lines
2.1 KiB
C++
83 lines
2.1 KiB
C++
/*
|
|
* \brief NOVA-specific signal-source client interface
|
|
* \author Norman Feske
|
|
* \date 2010-02-03
|
|
*
|
|
* On NOVA, the signal source server does not provide a blocking
|
|
* 'wait_for_signal' function because this kernel does no support
|
|
* out-of-order IPC replies. Instead, we use a shared semaphore
|
|
* to let the client block until a signal is present at the
|
|
* server. The shared semaphore gets initialized with the first
|
|
* call of 'wait_for_signal()'.
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2010-2012 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU General Public License version 2.
|
|
*/
|
|
|
|
#ifndef _INCLUDE__SIGNAL_SESSION__SOURCE_CLIENT_H_
|
|
#define _INCLUDE__SIGNAL_SESSION__SOURCE_CLIENT_H_
|
|
|
|
#include <nova/syscalls.h>
|
|
#include <base/rpc_client.h>
|
|
#include <signal_session/nova_source.h>
|
|
|
|
namespace Genode {
|
|
|
|
class Signal_source_client : public Rpc_client<Nova_signal_source>
|
|
{
|
|
private:
|
|
|
|
/**
|
|
* Capability with 'pt_sel' referring to a NOVA semaphore
|
|
*/
|
|
Native_capability _sem;
|
|
|
|
/**
|
|
* Request NOVA semaphore from signal-source server
|
|
*/
|
|
void _init_sem()
|
|
{
|
|
/* initialize semaphore only once */
|
|
if (_sem.valid()) return;
|
|
|
|
/* request mapping of semaphore capability selector */
|
|
_sem = call<Rpc_request_semaphore>();
|
|
}
|
|
|
|
public:
|
|
|
|
/**
|
|
* Constructor
|
|
*/
|
|
Signal_source_client(Signal_source_capability cap)
|
|
: Rpc_client<Nova_signal_source>(static_cap_cast<Nova_signal_source>(cap)) { }
|
|
|
|
|
|
/*****************************
|
|
** Signal source interface **
|
|
*****************************/
|
|
|
|
Signal wait_for_signal()
|
|
{
|
|
/* make sure that we have aquired the semaphore from the server */
|
|
_init_sem();
|
|
|
|
/* block on semaphore, will be unblocked if signal is available */
|
|
Nova::sm_ctrl(_sem.dst(), Nova::SEMAPHORE_DOWN);
|
|
|
|
/*
|
|
* Now that the server has unblocked the semaphore, we are sure
|
|
* that there is a signal pending. The following 'wait_for_signal'
|
|
* request will be immediately answered.
|
|
*/
|
|
return call<Rpc_wait_for_signal>();
|
|
}
|
|
};
|
|
}
|
|
|
|
#endif /* _INCLUDE__SIGNAL_SESSION__SOURCE_CLIENT_H_ */
|