1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at> 4 * Mostly copied from arch/x86/lib/delay.c 5 */ 6 7 #include <linux/export.h> 8 #include <linux/kernel.h> 9 #include <linux/delay.h> 10 #include <asm/param.h> 11 12 void __delay(unsigned long loops) 13 { 14 asm volatile( 15 "test %0,%0\n" 16 "jz 3f\n" 17 "jmp 1f\n" 18 19 ".align 16\n" 20 "1: jmp 2f\n" 21 22 ".align 16\n" 23 "2: dec %0\n" 24 " jnz 2b\n" 25 "3: dec %0\n" 26 27 : /* we don't need output */ 28 : "a" (loops) 29 ); 30 } 31 EXPORT_SYMBOL(__delay); 32 33 inline void __const_udelay(unsigned long xloops) 34 { 35 int d0; 36 37 xloops *= 4; 38 asm("mull %%edx" 39 : "=d" (xloops), "=&a" (d0) 40 : "1" (xloops), "0" 41 (loops_per_jiffy * (HZ/4))); 42 43 __delay(++xloops); 44 } 45 EXPORT_SYMBOL(__const_udelay); 46 47 void __udelay(unsigned long usecs) 48 { 49 __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ 50 } 51 EXPORT_SYMBOL(__udelay); 52 53 void __ndelay(unsigned long nsecs) 54 { 55 __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ 56 } 57 EXPORT_SYMBOL(__ndelay); 58