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TARGET_MAX32630FTHR/TOOLCHAIN_GCC_ARM/mxc_lock.h@172:65be27845400, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 20:53:29 2019 +0000
Revision:
172:65be27845400
Parent:
171:3a7713b1edbc 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AnnaBridge 171:3a7713b1edbc 1 /**
AnnaBridge 171:3a7713b1edbc 2 * @file
AnnaBridge 171:3a7713b1edbc 3 * @brief Exclusive access lock utility functions.
AnnaBridge 171:3a7713b1edbc 4 */
AnnaBridge 171:3a7713b1edbc 5 /* ****************************************************************************
AnnaBridge 171:3a7713b1edbc 6 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
AnnaBridge 171:3a7713b1edbc 7 *
AnnaBridge 171:3a7713b1edbc 8 * Permission is hereby granted, free of charge, to any person obtaining a
AnnaBridge 171:3a7713b1edbc 9 * copy of this software and associated documentation files (the "Software"),
AnnaBridge 171:3a7713b1edbc 10 * to deal in the Software without restriction, including without limitation
AnnaBridge 171:3a7713b1edbc 11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
AnnaBridge 171:3a7713b1edbc 12 * and/or sell copies of the Software, and to permit persons to whom the
AnnaBridge 171:3a7713b1edbc 13 * Software is furnished to do so, subject to the following conditions:
AnnaBridge 171:3a7713b1edbc 14 *
AnnaBridge 171:3a7713b1edbc 15 * The above copyright notice and this permission notice shall be included
AnnaBridge 171:3a7713b1edbc 16 * in all copies or substantial portions of the Software.
AnnaBridge 171:3a7713b1edbc 17 *
AnnaBridge 171:3a7713b1edbc 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
AnnaBridge 171:3a7713b1edbc 19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
AnnaBridge 171:3a7713b1edbc 20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
AnnaBridge 171:3a7713b1edbc 21 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
AnnaBridge 171:3a7713b1edbc 22 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
AnnaBridge 171:3a7713b1edbc 23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
AnnaBridge 171:3a7713b1edbc 24 * OTHER DEALINGS IN THE SOFTWARE.
AnnaBridge 171:3a7713b1edbc 25 *
AnnaBridge 171:3a7713b1edbc 26 * Except as contained in this notice, the name of Maxim Integrated
AnnaBridge 171:3a7713b1edbc 27 * Products, Inc. shall not be used except as stated in the Maxim Integrated
AnnaBridge 171:3a7713b1edbc 28 * Products, Inc. Branding Policy.
AnnaBridge 171:3a7713b1edbc 29 *
AnnaBridge 171:3a7713b1edbc 30 * The mere transfer of this software does not imply any licenses
AnnaBridge 171:3a7713b1edbc 31 * of trade secrets, proprietary technology, copyrights, patents,
AnnaBridge 171:3a7713b1edbc 32 * trademarks, maskwork rights, or any other form of intellectual
AnnaBridge 171:3a7713b1edbc 33 * property whatsoever. Maxim Integrated Products, Inc. retains all
AnnaBridge 171:3a7713b1edbc 34 * ownership rights.
AnnaBridge 171:3a7713b1edbc 35 *
AnnaBridge 171:3a7713b1edbc 36 * $Date: 2016-10-10 19:16:20 -0500 (Mon, 10 Oct 2016) $
AnnaBridge 171:3a7713b1edbc 37 * $Revision: 24663 $
AnnaBridge 171:3a7713b1edbc 38 *
AnnaBridge 171:3a7713b1edbc 39 *************************************************************************** */
AnnaBridge 171:3a7713b1edbc 40
AnnaBridge 171:3a7713b1edbc 41 /* Define to prevent redundant inclusion */
AnnaBridge 171:3a7713b1edbc 42 #ifndef _MXC_LOCK_H_
AnnaBridge 171:3a7713b1edbc 43 #define _MXC_LOCK_H_
AnnaBridge 171:3a7713b1edbc 44
AnnaBridge 171:3a7713b1edbc 45 /***** Includes *****/
AnnaBridge 171:3a7713b1edbc 46 #include "mxc_config.h"
AnnaBridge 171:3a7713b1edbc 47
AnnaBridge 171:3a7713b1edbc 48 #ifdef __cplusplus
AnnaBridge 171:3a7713b1edbc 49 extern "C" {
AnnaBridge 171:3a7713b1edbc 50 #endif
AnnaBridge 171:3a7713b1edbc 51
AnnaBridge 171:3a7713b1edbc 52 /**
AnnaBridge 171:3a7713b1edbc 53 * @ingroup sysconfig
AnnaBridge 171:3a7713b1edbc 54 * @defgroup mxc_lock_utilities Lock functions for Exclusive Access
AnnaBridge 171:3a7713b1edbc 55 * @brief Lock functions to obtain and release a variable for exclusive
AnnaBridge 171:3a7713b1edbc 56 * access. These functions are marked interrupt safe if they are
AnnaBridge 171:3a7713b1edbc 57 * interrupt safe.
AnnaBridge 171:3a7713b1edbc 58 * @{
AnnaBridge 171:3a7713b1edbc 59 */
AnnaBridge 171:3a7713b1edbc 60
AnnaBridge 171:3a7713b1edbc 61 /* **** Definitions **** */
AnnaBridge 171:3a7713b1edbc 62
AnnaBridge 171:3a7713b1edbc 63 /* **** Globals **** */
AnnaBridge 171:3a7713b1edbc 64
AnnaBridge 171:3a7713b1edbc 65 /* **** Function Prototypes **** */
AnnaBridge 171:3a7713b1edbc 66
AnnaBridge 171:3a7713b1edbc 67 /**
AnnaBridge 171:3a7713b1edbc 68 * @brief Attempts to acquire the lock.
AnnaBridge 171:3a7713b1edbc 69 * @details This in an interrupt safe function that can be used as a mutex.
AnnaBridge 171:3a7713b1edbc 70 * The lock variable must remain in scope until the lock is
AnnaBridge 171:3a7713b1edbc 71 * released. Will not block if another thread has already acquired
AnnaBridge 171:3a7713b1edbc 72 * the lock.
AnnaBridge 171:3a7713b1edbc 73 * @param lock Pointer to variable that is used for the lock.
AnnaBridge 171:3a7713b1edbc 74 * @param value Value to be place in the lock. Can not be 0.
AnnaBridge 171:3a7713b1edbc 75 *
AnnaBridge 171:3a7713b1edbc 76 * @return #E_NO_ERROR if everything successful, #E_BUSY if lock is taken.
AnnaBridge 171:3a7713b1edbc 77 */
AnnaBridge 171:3a7713b1edbc 78 __STATIC_INLINE int mxc_get_lock(uint32_t *lock, uint32_t value)
AnnaBridge 171:3a7713b1edbc 79 {
AnnaBridge 171:3a7713b1edbc 80 do {
AnnaBridge 171:3a7713b1edbc 81
AnnaBridge 171:3a7713b1edbc 82 // Return if the lock is taken by a different thread
AnnaBridge 171:3a7713b1edbc 83 if(__LDREXW((volatile uint32_t *)lock) != 0) {
AnnaBridge 171:3a7713b1edbc 84 return E_BUSY;
AnnaBridge 171:3a7713b1edbc 85 }
AnnaBridge 171:3a7713b1edbc 86
AnnaBridge 171:3a7713b1edbc 87 // Attempt to take the lock
AnnaBridge 171:3a7713b1edbc 88 } while(__STREXW(value, (volatile uint32_t *)lock) != 0);
AnnaBridge 171:3a7713b1edbc 89
AnnaBridge 171:3a7713b1edbc 90 // Do not start any other memory access until memory barrier is complete
AnnaBridge 171:3a7713b1edbc 91 __DMB();
AnnaBridge 171:3a7713b1edbc 92
AnnaBridge 171:3a7713b1edbc 93 return E_NO_ERROR;
AnnaBridge 171:3a7713b1edbc 94 }
AnnaBridge 171:3a7713b1edbc 95
AnnaBridge 171:3a7713b1edbc 96 /**
AnnaBridge 171:3a7713b1edbc 97 * @brief Free the given lock.
AnnaBridge 171:3a7713b1edbc 98 * @param[in,out] lock Pointer to the variable used for the lock. When the lock
AnnaBridge 171:3a7713b1edbc 99 * is free, the value pointed to by @p lock is set to zero.
AnnaBridge 171:3a7713b1edbc 100 */
AnnaBridge 171:3a7713b1edbc 101 __STATIC_INLINE void mxc_free_lock(uint32_t *lock)
AnnaBridge 171:3a7713b1edbc 102 {
AnnaBridge 171:3a7713b1edbc 103 // Ensure memory operations complete before releasing lock
AnnaBridge 171:3a7713b1edbc 104 __DMB();
AnnaBridge 171:3a7713b1edbc 105 *lock = 0;
AnnaBridge 171:3a7713b1edbc 106 }
AnnaBridge 171:3a7713b1edbc 107
AnnaBridge 171:3a7713b1edbc 108 /**@} end of group mxc_lock_utilities */
AnnaBridge 171:3a7713b1edbc 109
AnnaBridge 171:3a7713b1edbc 110 #ifdef __cplusplus
AnnaBridge 171:3a7713b1edbc 111 }
AnnaBridge 171:3a7713b1edbc 112 #endif
AnnaBridge 171:3a7713b1edbc 113
AnnaBridge 171:3a7713b1edbc 114 #endif /* _MXC_LOCK_H_ */