51 строка
1.3 KiB
C
51 строка
1.3 KiB
C
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/* delay.h: FRV delay code
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*
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* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_DELAY_H
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#define _ASM_DELAY_H
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#include <asm/param.h>
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#include <asm/timer-regs.h>
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/*
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* delay loop - runs at __core_clock_speed_HZ / 2 [there are 2 insns in the loop]
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*/
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extern unsigned long __delay_loops_MHz;
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static inline void __delay(unsigned long loops)
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{
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asm volatile("1: subicc %0,#1,%0,icc0 \n"
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" bnc icc0,#2,1b \n"
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: "=r" (loops)
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: "0" (loops)
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: "icc0"
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);
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}
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/*
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* Use only for very small delays ( < 1 msec). Should probably use a
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* lookup table, really, as the multiplications take much too long with
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* short delays. This is a "reasonable" implementation, though (and the
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* first constant multiplications gets optimized away if the delay is
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* a constant)
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*/
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extern unsigned long loops_per_jiffy;
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static inline void udelay(unsigned long usecs)
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{
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__delay(usecs * __delay_loops_MHz);
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}
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#define ndelay(n) udelay((n) * 5)
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#endif /* _ASM_DELAY_H */
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