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/**
* @file rtems/score/smplock.h
*
* This include file defines the interface for atomic locks
* which can be used in multiprocessor configurations.
*/
/*
* COPYRIGHT (c) 1989-2011.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#ifndef _RTEMS_LOCK_H
#define _RTEMS_LOCK_H
#include <rtems/score/isr.h>
/**
* @defgroup RTEMS Lock Interface
*
* @ingroup Score
*
*/
/**@{*/
#ifdef __cplusplus
extern "C" {
#endif
/**
* This type is used to lock elements for atomic access.
* This spinlock is a simple non-nesting spinlock, and
* may be used for short non-nesting accesses.
*/
typedef uint32_t SMP_lock_spinlock_simple_Control;
/**
* This type is used to lock elements for atomic access.
* This spinlock supports nesting, but is slightly more
* complicated to use. Please see the descriptions of
* obtain and release prior to using in order to understand
* the callers responsibilty of managing short interupt disable
* times.
*/
typedef struct {
SMP_lock_spinlock_simple_Control lock;
uint32_t count;
int cpu_id;
} SMP_lock_spinlock_nested_Control;
/**
* @brief Initialize a Lock
*
* This method is used to initialize the lock at @a lock.
*
* @param [in] lock is the address of the lock to obtain.
*/
void _SMP_lock_spinlock_simple_Initialize(
SMP_lock_spinlock_simple_Control *lock
);
/**
* @brief Obtain a Lock
*
* This method is used to obtain the lock at @a lock.
*
* @param [in] lock is the address of the lock to obtain.
*
* @return This method returns with processor interrupts disabled.
* The previous level is returned.
*/
ISR_Level _SMP_lock_spinlock_simple_Obtain(
SMP_lock_spinlock_simple_Control *lock
);
/**
* @brief Release a Lock
*
* This method is used to release the lock at @a lock.
*
* @param [in] lock is the address of the lock to obtain.
*/
void _SMP_lock_spinlock_simple_Release(
SMP_lock_spinlock_simple_Control *lock,
ISR_Level level
);
/**
* @brief Initialize a Lock
*
* This method is used to initialize the lock at @a lock.
*
* @param [in] lock is the address of the lock to obtain.
*/
void _SMP_lock_spinlock_nested_Initialize(
SMP_lock_spinlock_nested_Control *lock
);
/**
* @brief Obtain a Lock
*
* This method is used to obtain the lock at @a lock. ISR's are
* disabled when this routine returns and it is the callers responsibility
* to either:
*
* # Do something very short and then call
* _SMP_lock_spinlock_nested_Release or
* # Do something very sort, call isr enable, then when ready
* call isr_disable and _SMP_lock_spinlock_nested_Release
*
* @param [in] lock is the address of the lock to obtain.
*
* @return This method returns with processor interrupts disabled.
* The previous level is returned.
*/
ISR_Level _SMP_lock_spinlock_nested_Obtain(
SMP_lock_spinlock_nested_Control *lock
);
/**
* @brief Release a Lock
*
* This method is used to release the lock at @a lock.
*
* @note ISR's are reenabled by this method and are expected to be
* disabled upon entry to the method.
*
* @param [in] lock is the address of the lock to obtain.
*/
void _SMP_lock_spinlock_nested_Release(
SMP_lock_spinlock_nested_Control *lock,
ISR_Level level
);
#ifdef __cplusplus
}
#endif
/**@}*/
#endif
/* end of include file */
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