11.1Sjmcneill/* $NetBSD: timer.c,v 1.1 2025/11/16 20:11:47 jmcneill Exp $ */ 21.1Sjmcneill 31.1Sjmcneill/*- 41.1Sjmcneill * Copyright (c) 2025 Jared McNeill <jmcneill@invisible.ca> 51.1Sjmcneill * All rights reserved. 61.1Sjmcneill * 71.1Sjmcneill * Redistribution and use in source and binary forms, with or without 81.1Sjmcneill * modification, are permitted provided that the following conditions 91.1Sjmcneill * are met: 101.1Sjmcneill * 1. Redistributions of source code must retain the above copyright 111.1Sjmcneill * notice, this list of conditions and the following disclaimer. 121.1Sjmcneill * 2. Redistributions in binary form must reproduce the above copyright 131.1Sjmcneill * notice, this list of conditions and the following disclaimer in the 141.1Sjmcneill * documentation and/or other materials provided with the distribution. 151.1Sjmcneill * 161.1Sjmcneill * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 171.1Sjmcneill * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 181.1Sjmcneill * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 191.1Sjmcneill * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 201.1Sjmcneill * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 211.1Sjmcneill * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 221.1Sjmcneill * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 231.1Sjmcneill * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 241.1Sjmcneill * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 251.1Sjmcneill * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 261.1Sjmcneill * SUCH DAMAGE. 271.1Sjmcneill */ 281.1Sjmcneill 291.1Sjmcneill#include <lib/libsa/stand.h> 301.1Sjmcneill 311.1Sjmcneill#include <machine/pio.h> 321.1Sjmcneill 331.1Sjmcneill#include "timer.h" 341.1Sjmcneill 351.1Sjmcneill#define HW_BASE 0x0d800000 361.1Sjmcneill#define HW_TIMER (HW_BASE + 0x010) 371.1Sjmcneill 381.1Sjmcneillvoid 391.1Sjmcneilltimer_udelay(u_int usecs) 401.1Sjmcneill{ 411.1Sjmcneill uint32_t val, oval; 421.1Sjmcneill int64_t ticks = usecs * 2; /* Each tick is appx. 526.7ns */ 431.1Sjmcneill 441.1Sjmcneill val = in32(HW_TIMER); 451.1Sjmcneill while (ticks > 0) { 461.1Sjmcneill int64_t elapsed; 471.1Sjmcneill 481.1Sjmcneill oval = val; 491.1Sjmcneill val = in32(HW_TIMER); 501.1Sjmcneill if (val >= oval) { 511.1Sjmcneill elapsed = val - oval; 521.1Sjmcneill } else { 531.1Sjmcneill elapsed = (UINT32_MAX - oval) + val + 1; 541.1Sjmcneill } 551.1Sjmcneill ticks -= elapsed; 561.1Sjmcneill } 571.1Sjmcneill} 58