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