262 lines
8.8 KiB
C
262 lines
8.8 KiB
C
/****************************************************************************
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* include/nuttx/spinlock.h
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*
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* Copyright (C) 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __INCLUDE_NUTTX_SPINLOCK_H
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#define __INCLUDE_NUTTX_SPINLOCK_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#ifdef CONFIG_SPINLOCK
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/* The architecture specific spinlock.h header file must also provide the
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* following:
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*
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* SP_LOCKED - A definition of the locked state value (usually 1)
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* SP_UNLOCKED - A definition of the unlocked state value (usually 0)
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* spinlock_t - The type of a spinlock memory object.
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*
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* SP_LOCKED and SP_UNLOCKED must constants of type spinlock_t.
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*/
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#include <arch/spinlock.h>
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/****************************************************************************
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* Public Types
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****************************************************************************/
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struct spinlock_s
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{
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volatile spinlock_t sp_lock; /* Indicates if the spinlock is locked or
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* not. See the* values SP_LOCKED and
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* SP_UNLOCKED. */
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#ifdef CONFIG_SMP
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uint8_t sp_cpu; /* CPU holding the lock */
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uint16_t sp_count; /* The count of references by this CPU on
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* the lock */
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#endif
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};
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: up_testset
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*
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* Description:
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* Perform and atomic test and set operation on the provided spinlock.
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*
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* This function must be provided via the architecture-specific logoic.
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*
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* Input Parameters:
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* lock - The address of spinlock object.
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*
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* Returned Value:
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* The spinlock is always locked upon return. The value of previous value
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* of the spinlock variable is returned, either SP_LOCKED if the spinlock
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* as previously locked (meaning that the test-and-set operation failed to
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* obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
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* (meaning that we successfully obtained the lock)
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*
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****************************************************************************/
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spinlock_t up_testset(volatile FAR spinlock_t *lock);
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/****************************************************************************
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* Name: spin_initialize
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*
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* Description:
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* Initialize a non-reentrant spinlock object to its initial, unlocked state.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to be initialized.
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*
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* Returned Value:
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* None.
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*
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****************************************************************************/
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/* void spin_initialize(FAR spinlock_t *lock); */
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#define spin_initialize(i) do { (l) = SPI_UNLOCKED; } while (0)
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/****************************************************************************
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* Name: spin_initializer
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*
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* Description:
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* Initialize a re-entrant spinlock object to its initial, unlocked state.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to be initialized.
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*
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* Returned Value:
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* None.
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*
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****************************************************************************/
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void spin_initializer(FAR struct spinlock_s *lock);
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/****************************************************************************
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* Name: spin_lock
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*
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* Description:
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* If this CPU does not already hold the spinlock, then loop until the
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* spinlock is successfully locked.
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*
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* This implementation is non-reentrant and is prone to deadlocks in
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* the case that any logic on the same CPU attempts to take the lock
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* more than one
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to lock.
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*
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* Returned Value:
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* None. When the function returns, the spinlock was successfully locked
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* by this CPU.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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void spin_lock(FAR volatile spinlock_t *lock);
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/****************************************************************************
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* Name: spin_lockr
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*
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* Description:
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* If this CPU does not already hold the spinlock, then loop until the
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* spinlock is successfully locked.
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*
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* This implementation is re-entrant in the sense that it can called
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* numerous times from the same CPU without blocking. Of course,
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* spin_unlock() must be called the same number of times. NOTE: the
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* thread that originallly took the look may be executing on a different
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* CPU when it unlocks the spinlock.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to lock.
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*
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* Returned Value:
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* None. When the function returns, the spinlock was successfully locked
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* by this CPU.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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void spin_lockr(FAR struct spinlock_s *lock);
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/****************************************************************************
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* Name: spin_unlock
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*
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* Description:
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* Release one count on a non-reentrant spinlock.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to unlock.
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*
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* Returned Value:
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* None.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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/* void spin_unlock(FAR spinlock_t *lock); */
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#define spin_unlock(l) do { (l) = SP_UNLOCKED; } while (0)
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/****************************************************************************
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* Name: spin_unlockr
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*
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* Description:
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* Release one count on a re-entrant spinlock.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to unlock.
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*
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* Returned Value:
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* None.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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void spin_unlockr(FAR struct spinlock_s *lock);
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/****************************************************************************
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* Name: spin_islocked
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*
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* Description:
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* Release one count on a non-reentrant spinlock.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to test.
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*
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* Returned Value:
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* A boolean value: true the spinlock is locked; false if it is unlocked.
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*
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****************************************************************************/
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/* bool spin_islocked(FAR spinlock_t lock); */
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#define spin_islocked(l) ((l) == SP_LOCKED)
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/****************************************************************************
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* Name: spin_islockedr
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*
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* Description:
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* Release one count on a re-entrant spinlock.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to test.
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*
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* Returned Value:
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* A boolean value: true the spinlock is locked; false if it is unlocked.
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*
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****************************************************************************/
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/* bool spin_islockedr(FAR struct spinlock_s *lock); */
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#define spin_islockedr(l) ((l)->sp_lock == SP_LOCKED)
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#endif /* CONFIG_SPINLOCK */
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#endif /* __INCLUDE_NUTTX_SPINLOCK_H */
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