1/* 2 * Atomic read/write 3 * Copyright (c) 2001 by Abramo Bagnara <abramo@alsa-project.org> 4 * 5 * This library is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU Lesser General Public License as 7 * published by the Free Software Foundation; either version 2.1 of 8 * the License, or (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU Lesser General Public License for more details. 14 * 15 * You should have received a copy of the GNU Lesser General Public 16 * License along with this library; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 * 19 */ 20 21#include <stdlib.h> 22#include <time.h> 23#include <sched.h> 24#include "iatomic.h" 25 26void snd_atomic_read_wait(snd_atomic_read_t *t) 27{ 28 volatile const snd_atomic_write_t *w = t->write; 29 unsigned int loops = 0; 30 struct timespec ts; 31 while (w->begin != w->end) { 32 if (loops < MAX_SPIN_COUNT) { 33 sched_yield(); 34 loops++; 35 continue; 36 } 37 loops = 0; 38 ts.tv_sec = 0; 39 ts.tv_nsec = SPIN_SLEEP_DURATION; 40 nanosleep(&ts, NULL); 41 } 42} 43 44