106 lines
3.3 KiB
C
106 lines
3.3 KiB
C
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/**
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* \file
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* <!--
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* This file is part of BeRTOS.
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*
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* Bertos is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* As a special exception, you may use this file as part of a free software
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* library without restriction. Specifically, if other files instantiate
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* templates or use macros or inline functions from this file, or you compile
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* this file and link it with other files to produce an executable, this
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* file does not by itself cause the resulting executable to be covered by
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* the GNU General Public License. This exception does not however
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* invalidate any other reasons why the executable file might be covered by
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* the GNU General Public License.
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*
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* Copyright 2006 Develer S.r.l. (http://www.develer.com/)
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* All Rights Reserved.
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* -->
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*
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* \brief TODO:
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*
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*
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* \author Bernie Innocenti <bernie@codewiz.org>
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* \author Stefano Fedrigo <aleph@develer.com>
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*/
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#ifndef MWARE_RESOURCE_H
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#define MWARE_RESOURCE_H
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#include <drv/timer.h> // time_t
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#include <kern/sem.h>
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#warning FIXME:Revise me!
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/*
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* Abstract locking primitives used by host OS.
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*/
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typedef Semaphore ResourceLock;
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#define ResMan_sleep() timer_delay(1)
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#define ResMan_time_t mtime_t
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// Forward decl
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struct Observer;
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/**
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* Hold context information for a resource such as an audio channel.
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*
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* Each driver registers one or more Resource instances with the
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* ResMan using ResMan_Register().
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*
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* Clients can then allocate the resource through ResMan_Alloc()
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* providing a desired priority and an Observer for asynchronous
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* notification.
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*
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* Allocated resources can be stolen by other clients asking for a
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* higher priority. ResMan notifies a preemption request by invoking
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* the Observer of the current owner.
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*
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* The Observer callback must take whatever action is needed to
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* release the resource as soon as possible to avoid blocking the
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* new owner.
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*/
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typedef struct Resource
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{
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//Private
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/// Control access to fields below.
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Semaphore lock;
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/// Pointer to current owner's observer. NULL if resource is free.
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struct Observer *owner;
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/// Priority of current owner (higher values mean higher priority).
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int pri;
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/// Queue of processes waiting to obtain the resource.
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List queue;
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} Resource;
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/// Event sent by ResMan to owners when to request resource release.
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enum { EVENT_RELEASE = 1 };
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/// Try to allocate a resource \a res with priority \a pri for at most \a timeout ticks.
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bool ResMan_Alloc(Resource *res, int pri, ResMan_time_t timeout, struct Observer *releaseRequest);
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/// Free resource \a res. Will eventually wake-up other queued owners.
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void ResMan_Free(Resource *res);
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void ResMan_Init(Resource *res);
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#endif /* MWARE_RESOURCE_H */
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