File: /usr/src/linux/include/asm-parisc/delay.h

1     #ifndef _PARISC_DELAY_H
2     #define _PARISC_DELAY_H
3     
4     #include <asm/system.h>    /* for mfctl() */
5     #include <asm/processor.h> /* for boot_cpu_data */
6     
7     
8     /*
9      * Copyright (C) 1993 Linus Torvalds
10      *
11      * Delay routines
12      */
13     
14     extern unsigned long loops_per_sec;
15     
16     static __inline__ void __delay(unsigned long loops) {
17     	asm volatile(
18     	"	.balignl	64,0x34000034
19     		addib,UV -1,%0,.
20     		nop"
21     		: "=r" (loops) : "0" (loops));
22     }
23     
24     static __inline__ void __cr16_delay(unsigned long clocks) {
25     	unsigned long start;
26     
27     	/*
28     	 * Note: Due to unsigned math, cr16 rollovers shouldn't be
29     	 * a problem here. However, on 32 bit, we need to make sure
30     	 * we don't pass in too big a value. The current default
31     	 * value of MAX_UDELAY_MS should help prevent this.
32     	 */
33     
34     	start = mfctl(16);
35     	while ((mfctl(16) - start) < clocks)
36     	    ;
37     }
38     
39     static __inline__ void __udelay(unsigned long usecs) {
40     	__cr16_delay(usecs * ((unsigned long)boot_cpu_data.cpu_hz / 1000000UL));
41     }
42     
43     #define udelay(n) __udelay(n)
44     
45     #endif /* defined(_PARISC_DELAY_H) */
46