105 lines
4.3 KiB
C
105 lines
4.3 KiB
C
/****************************************************************************
|
|
* arch/arm/include/spinlock.h
|
|
*
|
|
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifndef __ARCH_ARM_INCLUDE_SPINLOCK_H
|
|
#define __ARCH_ARM_INCLUDE_SPINLOCK_H
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#ifndef __ASSEMBLY__
|
|
# include <stdint.h>
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
#define SP_UNLOCKED 0 /* The Un-locked state */
|
|
#define SP_LOCKED 1 /* The Locked state */
|
|
|
|
/****************************************************************************
|
|
* Public Types
|
|
****************************************************************************/
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
/* The Type of a spinlock.
|
|
*
|
|
* ARMv6 architecture introuced the concept of exclusive accesses to memory
|
|
* locations in the form of the Load-Exclusive (LDREX) and Store-Exclusive
|
|
* (STREX) instructions in ARM and Thumb instruction sets. ARMv6K extended
|
|
* this to included byte, halfword, and doubleword variants of LDREX and
|
|
* STREX. ARMv7-M supports byte and halfwor, but not the doudleword varient
|
|
* (ARMv6-M does not support exlusive access)
|
|
*
|
|
* ARM architectures prior to ARMv6 supported SWP and SWPB instructions that
|
|
* atomically swap a 32-bit word for byte value between a register and a
|
|
* memory location. From the ARMv6 architecture, ARM deprecates the use
|
|
* of SWP and SWPB.
|
|
*/
|
|
|
|
typedef uint8_t spinlock_t;
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: up_testset
|
|
*
|
|
* Description:
|
|
* Perform and atomic test and set operation on the provided spinlock.
|
|
*
|
|
* This function must be provided via the architecture-specific logoic.
|
|
*
|
|
* Input Parameters:
|
|
* lock - The address of spinlock object.
|
|
*
|
|
* Returned Value:
|
|
* The spinlock is always locked upon return. The value of previous value
|
|
* of the spinlock variable is returned, either SP_LOCKED if the spinlock
|
|
* as previously locked (meaning that the test-and-set operation failed to
|
|
* obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
|
|
* (meaning that we successfully obtained the lock)
|
|
*
|
|
****************************************************************************/
|
|
|
|
/* See prototype in nuttx/include/nuttx/spinlock.h */
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
#endif /* __ARCH_ARM_INCLUDE_SPINLOCK_H */
|