1 /* $NetBSD: clock.c,v 1.12 2009/03/18 10:22:26 cegger 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 <lib/libsa/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 mftb(void); 41 42 static inline u_quad_t 43 mftb(void) 44 { 45 u_long scratch; 46 u_quad_t tb; 47 48 __asm ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b" 49 : "=r"(tb), "=r"(scratch)); 50 return (tb); 51 } 52 53 /* 54 * Wait for about n microseconds (at least!). 55 */ 56 void 57 delay(u_int n) 58 { 59 u_quad_t tb; 60 u_long tbh, tbl, scratch; 61 62 tb = mftb(); 63 tb += (n * 1000 + NS_PER_TICK - 1) / NS_PER_TICK; 64 tbh = tb >> 32; 65 tbl = tb; 66 __asm ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f;" 67 "mftb %0; cmpw 0, %0,%2; blt 1b; 2:" 68 : "=&r"(scratch) : "r"(tbh), "r"(tbl)); 69 } 70