rockbox/firmware/kernel/include/semaphore.h
Michael Sevakis 6ed00870ab Base scheduler queues off linked lists and do cleanup/consolidation
Abstracts threading from itself a bit, changes the way its queues are
handled and does type hiding for that as well.

Do alot here due to already required major brain surgery.

Threads may now be on a run queue and a wait queue simultaneously so
that the expired timer only has to wake the thread but not remove it
from the wait queue which simplifies the implicit wake handling.

List formats change for wait queues-- doubly-linked, not circular.
Timeout queue is now singly-linked. The run queue is still circular
as before.

Adds a better thread slot allocator that may keep the slot marked as
used regardless of the thread state. Assists in dumping special tasks
that switch_thread was tasked to perform (blocking tasks).

Deletes alot of code yet surprisingly, gets larger than expected.
Well, I'm not not minding that for the time being-- omlettes and break
a few eggs and all that.

Change-Id: I0834d7bb16b2aecb2f63b58886eeda6ae4f29d59
2014-08-16 05:15:37 -04:00

39 lines
1.5 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Björn Stenberg
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef SEMAPHORE_H
#define SEMAPHORE_H
#include "thread.h"
struct semaphore
{
struct __wait_queue queue; /* Waiter list */
int volatile count; /* # of waits remaining before unsignaled */
int max; /* maximum # of waits to remain signaled */
IF_COP( struct corelock cl; ) /* multiprocessor sync */
};
extern void semaphore_init(struct semaphore *s, int max, int start);
extern int semaphore_wait(struct semaphore *s, int timeout);
extern void semaphore_release(struct semaphore *s);
#endif /* SEMAPHORE_H */