genode/repos/os/include/timer_session/timer_session.h
Martin Stein 8750e373a0 timer session: add elapsed_us method
As timer sessions are not expected to be microseconds precise (because
of RPC latency and scheduling), the session interface provided only a
method 'elapsed_ms' although the back end of this method in the timer
driver works with microseconds.

However, in some cases it makes sense to have a method 'elapsed_us'. The
values it returns might be milliseconds away from the "real" time but it
allows you to work with delays smaller than a millisecond without
getting a zero delta value.

This commit is motivated by the need for fast bursts of calibration
steps for the time interpolation in the new timer connection.

Ref #2400
2017-08-23 14:08:36 +02:00

91 lines
2.2 KiB
C++

/*
* \brief Timer session interface
* \author Norman Feske
* \author Markus Partheymueller
* \date 2006-08-15
*/
/*
* Copyright (C) 2006-2017 Genode Labs GmbH
* Copyright (C) 2012 Intel Corporation
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__TIMER_SESSION__TIMER_SESSION_H_
#define _INCLUDE__TIMER_SESSION__TIMER_SESSION_H_
#include <base/signal.h>
#include <session/session.h>
namespace Timer { struct Session; }
struct Timer::Session : Genode::Session
{
typedef Genode::Signal_context_capability Signal_context_capability;
/**
* \noapi
*/
static const char *service_name() { return "Timer"; }
enum { CAP_QUOTA = 2 };
virtual ~Session() { }
/**
* Program single timeout (relative from now in microseconds)
*/
virtual void trigger_once(unsigned us) = 0;
/**
* Program periodic timeout (in microseconds)
*
* The first period will be triggered after 'us' at the latest,
* but it might be triggered earlier as well.
*/
virtual void trigger_periodic(unsigned us) = 0;
/**
* Register timeout signal handler
*/
virtual void sigh(Genode::Signal_context_capability sigh) = 0;
/**
* Return number of elapsed milliseconds since session creation
*/
virtual unsigned long elapsed_ms() const = 0;
virtual unsigned long elapsed_us() const = 0;
/**
* Client-side convenience method for sleeping the specified number
* of milliseconds
*/
virtual void msleep(unsigned ms) = 0;
/**
* Client-side convenience method for sleeping the specified number
* of microseconds
*/
virtual void usleep(unsigned us) = 0;
/*********************
** RPC declaration **
*********************/
GENODE_RPC(Rpc_trigger_once, void, trigger_once, unsigned);
GENODE_RPC(Rpc_trigger_periodic, void, trigger_periodic, unsigned);
GENODE_RPC(Rpc_sigh, void, sigh, Genode::Signal_context_capability);
GENODE_RPC(Rpc_elapsed_ms, unsigned long, elapsed_ms);
GENODE_RPC(Rpc_elapsed_us, unsigned long, elapsed_us);
GENODE_RPC_INTERFACE(Rpc_trigger_once, Rpc_trigger_periodic,
Rpc_sigh, Rpc_elapsed_ms, Rpc_elapsed_us);
};
#endif /* _INCLUDE__TIMER_SESSION__TIMER_SESSION_H_ */