Home | History | Annotate | Download | only in lib 
      1 /*******************************************************************************
      2 * Copyright (C) 2018 Cadence Design Systems, Inc.
      3 *
      4 * Permission is hereby granted, free of charge, to any person obtaining
      5 * a copy of this software and associated documentation files (the
      6 * "Software"), to use this Software with Cadence processor cores only and
      7 * not with any other processors and platforms, subject to
      8 * the following conditions:
      9 *
     10 * The above copyright notice and this permission notice shall be included
     11 * in all copies or substantial portions of the Software.
     12 *
     13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     14 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     15 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     16 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
     17 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     18 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     19 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     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