1 /*******************************************************************************
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5 * a copy of this software and associated documentation files (the
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20 
21 ******************************************************************************/
22 
23 /*******************************************************************************
24  * mutex.h
25  *
26  *
27  * Implementation of "non-robust" Szymanski linear-waiting algorithm. Types of
28  * failures tolerated by Szymanski's "robust" algorithm are not specific for
29  * Xtensa DSP cluster and therefore more lightweight version of the algorithm
30  * is used. FIFO servicing property is of low importance, and faster/smaller
31  * version with linear-wait property is preferable.
32  *
33  * We assume there is just a single mutex in the system, and all communication
34  * variables are defined somewhere in board-specific headers and imported here
35  * by means of macros MUTEX_SHARED_READ/WRITE.
36  ******************************************************************************/
37 
38 #ifndef __MUTEX_H
39 #define __MUTEX_H
40 
41 /*******************************************************************************
42  * Imported macros
43  ******************************************************************************/
44 
45 #if !defined(MUTEX_SHARED_READ) || !defined(MUTEX_SHARED_WRITE)
46 #error "Macros MUTEX_SHARED_READ and/or MUTEX_SHARED_WRITE not defined"
47 #endif
48 
49 /*******************************************************************************
50  * Entry points
51  ******************************************************************************/
52 
53 /* ...acquire global mutex from i-th core */
54 extern void mutex_lock(u32 i);
55 
56 /* ...release global mutex from i-th core */
57 extern void mutex_unlock(u32 i);
58 
59 #endif  /* __MUTEX_H */
60