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David Howellsb920de12008-02-08 04:19:31 -08001/* 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 */
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}
33EXPORT_SYMBOL(__delay);
34
35/*
36 * handle a delay specified in terms of microseconds
37 */
38void __udelay(unsigned long usecs)
39{
40 signed long ioclk, stop;
41
42 /* usecs * CLK / 1E6 */
43 stop = __muldiv64u(usecs, MN10300_TSCCLK, 1000000);
44 stop = TMTSCBC - stop;
45
46 do {
47 ioclk = TMTSCBC;
48 } while (stop < ioclk);
49}
50EXPORT_SYMBOL(__udelay);