1 /* MN10300 Short delay interpolation routines 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11 #include <linux/module.h> 12 #include <linux/sched.h> 13 #include <linux/delay.h> 14 #include <asm/div64.h> 15 16 /* 17 * basic delay loop 18 */ __delay(unsigned long loops)19void __delay(unsigned long loops) 20 { 21 int d0; 22 23 asm volatile( 24 " bra 1f \n" 25 " .align 4 \n" 26 "1: bra 2f \n" 27 " .align 4 \n" 28 "2: add -1,%0 \n" 29 " bne 2b \n" 30 : "=&d" (d0) 31 : "0" (loops) 32 : "cc"); 33 } 34 EXPORT_SYMBOL(__delay); 35 36 /* 37 * handle a delay specified in terms of microseconds 38 */ __udelay(unsigned long usecs)39void __udelay(unsigned long usecs) 40 { 41 unsigned long start, stop, cnt; 42 43 /* usecs * CLK / 1E6 */ 44 stop = __muldiv64u(usecs, MN10300_TSCCLK, 1000000); 45 start = TMTSCBC; 46 47 do { 48 cnt = start - TMTSCBC; 49 } while (cnt < stop); 50 } 51 EXPORT_SYMBOL(__udelay); 52