/* 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__ */ |