mirror of https://github.com/ARMmbed/mbed-os.git
84 lines
2.8 KiB
C
84 lines
2.8 KiB
C
/**
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* @file
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* @brief Exclusive access lock utility functions.
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*/
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/* ****************************************************************************
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* Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
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* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* Except as contained in this notice, the name of Maxim Integrated
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* Products, Inc. shall not be used except as stated in the Maxim Integrated
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* Products, Inc. Branding Policy.
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*
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* The mere transfer of this software does not imply any licenses
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* of trade secrets, proprietary technology, copyrights, patents,
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* trademarks, maskwork rights, or any other form of intellectual
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* property whatsoever. Maxim Integrated Products, Inc. retains all
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* ownership rights.
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*
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* $Date: 2017-02-14 18:16:40 -0600 (Tue, 14 Feb 2017) $
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* $Revision: 26426 $
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*
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*************************************************************************** */
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/* Define to prevent redundant inclusion */
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#ifndef _MXC_LOCK_H_
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#define _MXC_LOCK_H_
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/* **** Includes **** */
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#include "mxc_config.h"
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#include "mxc_lock.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* ************************************************************************** */
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int mxc_get_lock(uint32_t *lock, uint32_t value)
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{
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do {
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// Return if the lock is taken by a different thread
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if(__LDREXW((volatile unsigned long *)lock) != 0) {
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return E_BUSY;
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}
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// Attempt to take the lock
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} while(__STREXW(value, (volatile unsigned long *)lock) != 0);
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// Do not start any other memory access until memory barrier is complete
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__DMB();
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return E_NO_ERROR;
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}
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/* ************************************************************************** */
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void mxc_free_lock(uint32_t *lock)
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{
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// Ensure memory operations complete before releasing lock
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__DMB();
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*lock = 0;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* _MXC_LOCK_H_ */
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