1 /* $NetBSD: clock.c,v 1.6 1999/06/28 01:20:44 sakamoto Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996 Wolfgang Solfrank. 5 * Copyright (C) 1995, 1996 TooLs GmbH. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by TooLs GmbH. 19 * 4. The name of TooLs GmbH may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 28 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 30 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 31 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <stand.h> 35 #include <sys/param.h> 36 #include <dev/isa/isareg.h> 37 #include <dev/ic/i8253reg.h> 38 #include "boot.h" 39 40 static inline u_quad_t 41 mftb() 42 { 43 u_long scratch; 44 u_quad_t tb; 45 46 asm ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b" 47 : "=r"(tb), "=r"(scratch)); 48 return (tb); 49 } 50 51 /* 52 * Wait for about n microseconds (at least!). 53 */ 54 void 55 delay(n) 56 u_int n; 57 { 58 u_quad_t tb; 59 u_long tbh, tbl, scratch; 60 61 tb = mftb(); 62 tb += (n * 1000 + NS_PER_TICK - 1) / NS_PER_TICK; 63 tbh = tb >> 32; 64 tbl = tb; 65 asm ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f; mftb %0; cmpw 0, %0,%2; blt 1b; 2:" 66 :: "r"(scratch), "r"(tbh), "r"(tbl)); 67 } 68