summaryrefslogtreecommitdiffstats
path: root/arch/mips/lib/delay.c
blob: f69c6b569eb3b7c42b4ea756e56f847e7bd75fe2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 by Waldorf Electronics
 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2007  Maciej W. Rozycki
 */
#include <linux/module.h>
#include <linux/param.h>
#include <linux/smp.h>

#include <asm/compiler.h>
#include <asm/war.h>

inline void __delay(unsigned int loops)
{
	__asm__ __volatile__ (
	"	.set	noreorder				\n"
	"	.align	3					\n"
	"1:	bnez	%0, 1b					\n"
	"	subu	%0, 1					\n"
	"	.set	reorder					\n"
	: "=r" (loops)
	: "0" (loops));
}
EXPORT_SYMBOL(__delay);

/*
 * Division by multiplication: you don't have to worry about
 * loss of precision.
 *
 * Use only for very small delays ( < 1 msec).  Should probably use a
 * lookup table, really, as the multiplications take much too long with
 * short delays.  This is a "reasonable" implementation, though (and the
 * first constant multiplications gets optimized away if the delay is
 * a constant)
 */

void __udelay(unsigned long us)
{
	unsigned int lpj = current_cpu_data.udelay_val;

	__delay((us * 0x000010c7 * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__udelay);

void __ndelay(unsigned long ns)
{
	unsigned int lpj = current_cpu_data.udelay_val;

	__delay((us * 0x00000005 * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__ndelay);
OpenPOWER on IntegriCloud