1/*
2 * include/asm-xtensa/delay.h
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License.  See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2001 - 2005 Tensilica Inc.
9 *
10 */
11
12#ifndef _XTENSA_DELAY_H
13#define _XTENSA_DELAY_H
14
15#include <asm/timex.h>
16#include <asm/param.h>
17
18extern unsigned long loops_per_jiffy;
19
20static inline void __delay(unsigned long loops)
21{
22	if (__builtin_constant_p(loops) && loops < 2)
23		__asm__ __volatile__ ("nop");
24	else if (loops >= 2)
25		/* 2 cycles per loop. */
26		__asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
27				: "+r" (loops));
28}
29
30/* Undefined function to get compile-time error */
31void __bad_udelay(void);
32void __bad_ndelay(void);
33
34#define __MAX_UDELAY 30000
35#define __MAX_NDELAY 30000
36
37static inline void __udelay(unsigned long usecs)
38{
39	unsigned long start = get_ccount();
40	unsigned long cycles = (usecs * (ccount_freq >> 15)) >> 5;
41
42	/* Note: all variables are unsigned (can wrap around)! */
43	while (((unsigned long)get_ccount()) - start < cycles)
44		cpu_relax();
45}
46
47static inline void udelay(unsigned long usec)
48{
49	if (__builtin_constant_p(usec) && usec >= __MAX_UDELAY)
50		__bad_udelay();
51	else
52		__udelay(usec);
53}
54
55static inline void __ndelay(unsigned long nsec)
56{
57	/*
58	 * Inner shift makes sure multiplication doesn't overflow
59	 * for legitimate nsec values
60	 */
61	unsigned long cycles = (nsec * (ccount_freq >> 15)) >> 15;
62	__delay(cycles);
63}
64
65#define ndelay(n) ndelay(n)
66
67static inline void ndelay(unsigned long nsec)
68{
69	if (__builtin_constant_p(nsec) && nsec >= __MAX_NDELAY)
70		__bad_ndelay();
71	else
72		__ndelay(nsec);
73}
74
75#endif
76