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/*! \file include/critsec.h
\brief Interface: critical section management
\author Joseph A. Woolley <jawoolley@users.sourceforge.net>
Defines types and functions to implement critical sections.
*/
/*
* The contents of this file are subject to the Mozilla Public License
* Version 1.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License
* at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and
* limitations under the License.
*
* The Original Code is legOS code, released October 17, 1999.
*
* The Initial Developer of the Original Code is Markus L. Noga.
* Portions created by Markus L. Noga are Copyright (C) 1999
* Markus L. Noga. All Rights Reserved.
*
* Contributor(s): Joseph A. Woolley <jawoolley@users.sourceforge.net>
*/
#if !defined(__critsec_h__)
#define __critsec_h__
#if defined(__cplusplus)
extern "C" {
#endif // __cplusplus
#include <config.h>
#if defined(CONF_TM) && defined(CONF_CRITICAL_SECTIONS)
#include <sys/tm.h>
#include <atomic.h>
#ifndef DOXYGEN_SHOULD_SKIP_INTERNALS
//! critical section data structure
/*! tracks current count (level of nesting)
and the task that is in the critical section(s)
count will be zero when no tasks are within
a critical section.
*/
struct critsec {
atomic_t count;
tdata_t* task;
};
#endif // DOXYGEN_SHOULD_SKIP_INTERNALS
//! critical section type definition
typedef struct critsec critsec_t;
//! don't use locked_decrement anymore but atomic_dec()
/*! @deprecated use atomic_dec() instead
*/
#define locked_decrement(counter) atomic_dec(counter)
//! wakeup when critical section is available
/*! wakeup function used to sleep a task until a critical
section is available. called while processing an
interrupt, so interrupts are already disabled.
\return 0 to continue waiting, non-zero to wakeup task.
\sa enter_critical_section
*/
extern wakeup_t wait_critical_section(wakeup_t data);
//! initialize critical section
/*! sets count field of critical section to zero
\param cs pointer to critical section (critsec_t)
\return always 0
\sa enter_critical_section
\sa leave_critical_section
\sa destroy_critical_section
*/
#define initialize_critical_section(cs) (cs)->count=0
//! enter critical section
/*! block other tasks if they attempt to enter a
region of code protected by the same critical section.
\param cs pointer to critical section (critsec_t)
\return 1 if successful, 0 if failure
\sa initialize_critical_section
\sa leave_critical_section
\sa destroy_critical_section
*/
extern int enter_critical_section(critsec_t* cs);
//! leave critical section
/*! allow other tasks to enter critical regions
of code protected by this critical section.
\param cs pointer to critical section (critsec_t)
\return results of locked_decrement (always 0)
\sa initialize_critical_section
\sa enter_critical_section
\sa destroy_critical_section
*/
#define leave_critical_section(cs) atomic_dec(&(cs)->count)
//! destroy critical section (does nothing)
/*! currently there are no resources that are dynamically
allocated.
\param cs pointer to critical section (critsec_t)
\sa initialize_critical_section
\sa enter_critical_section
\sa leave_critical_section
*/
#define destroy_critical_section(cs)
#endif // CONF_TM && CONF_CRITICAL_SECTIONS
#if defined(__cplusplus)
}
#endif // __cplusplus
#endif // __critsec_h__
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