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Linux kernel mirror (for testing)
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linux
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 /* 2 cycles per loop. */
23 __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
24 : "=r" (loops) : "0" (loops));
25}
26
27/* For SMP/NUMA systems, change boot_cpu_data to something like
28 * local_cpu_data->... where local_cpu_data points to the current
29 * cpu. */
30
31static __inline__ void udelay (unsigned long usecs)
32{
33 unsigned long start = get_ccount();
34 unsigned long cycles = usecs * (loops_per_jiffy / (1000000UL / HZ));
35
36 /* Note: all variables are unsigned (can wrap around)! */
37 while (((unsigned long)get_ccount()) - start < cycles)
38 ;
39}
40
41#endif