1/*
2 * Delay loops based on the OpenRISC implementation.
3 *
4 * Copyright (C) 2012 ARM Limited
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17 *
18 * Author: Will Deacon <will.deacon@arm.com>
19 */
20
21#include <linux/delay.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/timex.h>
26
27void __delay(unsigned long cycles)
28{
29	cycles_t start = get_cycles();
30
31	while ((get_cycles() - start) < cycles)
32		cpu_relax();
33}
34EXPORT_SYMBOL(__delay);
35
36inline void __const_udelay(unsigned long xloops)
37{
38	unsigned long loops;
39
40	loops = xloops * loops_per_jiffy * HZ;
41	__delay(loops >> 32);
42}
43EXPORT_SYMBOL(__const_udelay);
44
45void __udelay(unsigned long usecs)
46{
47	__const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
48}
49EXPORT_SYMBOL(__udelay);
50
51void __ndelay(unsigned long nsecs)
52{
53	__const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
54}
55EXPORT_SYMBOL(__ndelay);
56