1 /* ****************************************************************************
2 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included
12 * in all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * Except as contained in this notice, the name of Maxim Integrated
23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
24 * Products, Inc. Branding Policy.
25 *
26 * The mere transfer of this software does not imply any licenses
27 * of trade secrets, proprietary technology, copyrights, patents,
28 * trademarks, maskwork rights, or any other form of intellectual
29 * property whatsoever. Maxim Integrated Products, Inc. retains all
30 * ownership rights.
31 *
32 * $Date: 2018-12-18 15:37:22 -0600 (Tue, 18 Dec 2018) $
33 * $Revision: 40072 $
34 *
35 *************************************************************************** */
36
37 /* Define to prevent redundant inclusion */
38 #ifndef _MXC_LOCK_H_
39 #define _MXC_LOCK_H_
40
41 /* **** Includes **** */
42 #include "mxc_config.h"
43 #include "mxc_lock.h"
44
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48
49 #if defined ( __ICCARM__ )
50 #define MXC_LOCK_CAST unsigned int volatile *
51 #else
52 #define MXC_LOCK_CAST volatile unsigned long *
53 #endif
54
55 /* ************************************************************************** */
mxc_get_lock(uint32_t * lock,uint32_t value)56 int mxc_get_lock(uint32_t *lock, uint32_t value)
57 {
58 do {
59
60 // Return if the lock is taken by a different thread
61 if(__LDREXW((MXC_LOCK_CAST)lock) != 0) {
62 return E_BUSY;
63 }
64
65 // Attempt to take the lock
66 } while(__STREXW(value, (MXC_LOCK_CAST)lock) != 0);
67
68 // Do not start any other memory access until memory barrier is complete
69 __DMB();
70
71 return E_NO_ERROR;
72 }
73
74 /* ************************************************************************** */
mxc_free_lock(uint32_t * lock)75 void mxc_free_lock(uint32_t *lock)
76 {
77 // Ensure memory operations complete before releasing lock
78 __DMB();
79 *lock = 0;
80 }
81
82 #ifdef __cplusplus
83 }
84 #endif
85 #endif /* _MXC_LOCK_H_ */
86