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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/unicore32/include/asm/delay.h
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* Delay routines, using a pre-computed "loops_per_second" value.
*/
#ifndef __UNICORE_DELAY_H__
#define __UNICORE_DELAY_H__
#include <asm/param.h> /* HZ */
extern void __delay(int loops);
/*
* This function intentionally does not exist; if you see references to
* it, it means that you're calling udelay() with an out of range value.
*
* With currently imposed limits, this means that we support a max delay
* of 2000us. Further limits: HZ<=1000 and bogomips<=3355
*/
extern void __bad_udelay(void);
/*
* 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)
*/
extern void __udelay(unsigned long usecs);
extern void __const_udelay(unsigned long);
#define MAX_UDELAY_MS 2
#define udelay(n) \
(__builtin_constant_p(n) ? \
((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \
__const_udelay((n) * ((2199023U*HZ)>>11))) : \
__udelay(n))
#endif /* __UNICORE_DELAY_H__ */
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