981d028c09
* Seal away private thread and kernel definitions and declarations into the internal headers in order to better hide internal structure. * Add a thread-common.c file that keeps shared functions together. List functions aren't messed with since that's about to be changed to different ones. * It is necessary to modify some ARM/PP stuff since GCC was complaining about constant pool distance and I would rather not force dump it. Just bl the cache calls in the startup and exit code and let it use veneers if it must. * Clean up redundant #includes in relevant areas and reorganize them. * Expunge useless and dangerous stuff like remove_thread(). Change-Id: I6e22932fad61a9fac30fd1363c071074ee7ab382
56 lines
2.2 KiB
C
56 lines
2.2 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2014 by Michael Sevakis
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef MRSW_LOCK_H
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#define MRSW_LOCK_H
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#include "thread.h"
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/* Multi-reader, single-writer object that allows mutltiple readers or a
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* single writer thread access to a critical section.
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*
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* Readers and writers, as with a mutex, may claim the lock recursively for
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* the same type of access they were already granted.
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*
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* Writers are trivially granted read access by ignoring the request; the
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* object is not changed.
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*
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* Reader promotion to writer is NOT supported and a reader attempting write
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* access will result in a deadlock. That could change but for now, be warned.
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*
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* Full priority inheritance is implemented.
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*/
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struct mrsw_lock
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{
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int volatile count; /* rd/wr counter; >0 = reader(s), <0 = writer */
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struct thread_entry *queue;
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struct blocker_splay splay; /* priority inheritance info
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for waiters */
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uint8_t rdrecursion[MAXTHREADS]; /* per-thread reader recursion counts */
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IF_COP( struct corelock cl; )
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};
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void mrsw_init(struct mrsw_lock *mrsw);
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void mrsw_read_acquire(struct mrsw_lock *mrsw);
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void mrsw_read_release(struct mrsw_lock *mrsw);
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void mrsw_write_acquire(struct mrsw_lock *mrsw);
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void mrsw_write_release(struct mrsw_lock *mrsw);
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#endif /* MRSW_LOCK_H */
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