mirror of https://gitee.com/openkylin/linux.git
61 lines
1.1 KiB
C
61 lines
1.1 KiB
C
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/*
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* Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
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* Mostly copied from arch/x86/lib/delay.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <asm/param.h>
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void __delay(unsigned long loops)
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{
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asm volatile(
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"test %0,%0\n"
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"jz 3f\n"
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"jmp 1f\n"
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".align 16\n"
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"1: jmp 2f\n"
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".align 16\n"
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"2: dec %0\n"
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" jnz 2b\n"
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"3: dec %0\n"
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: /* we don't need output */
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: "a" (loops)
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);
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}
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EXPORT_SYMBOL(__delay);
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inline void __const_udelay(unsigned long xloops)
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{
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int d0;
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xloops *= 4;
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asm("mull %%edx"
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: "=d" (xloops), "=&a" (d0)
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: "1" (xloops), "0"
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(loops_per_jiffy * (HZ/4)));
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__delay(++xloops);
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}
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EXPORT_SYMBOL(__const_udelay);
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void __udelay(unsigned long usecs)
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{
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__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
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}
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EXPORT_SYMBOL(__udelay);
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void __ndelay(unsigned long nsecs)
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{
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__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
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}
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EXPORT_SYMBOL(__ndelay);
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