5636919b5c
Outlining fixes the issue were on certain CPUs such as the R10000 family the delay loop would need an extra cycle if it overlaps a cacheline boundary. The rewrite also fixes build errors with GCC 4.4 which was changed in way incompatible with the kernel's inline assembly. Relying on pure C for computation of the delay value removes the need for explicit. The price we pay is a slight slowdown of the computation - to be fixed on another day. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
56 lines
1.4 KiB
C
56 lines
1.4 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994 by Waldorf Electronics
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* Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
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* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
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* Copyright (C) 2007 Maciej W. Rozycki
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*/
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#include <linux/module.h>
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#include <linux/param.h>
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#include <linux/smp.h>
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#include <asm/compiler.h>
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#include <asm/war.h>
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inline void __delay(unsigned int loops)
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{
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__asm__ __volatile__ (
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" .set noreorder \n"
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" .align 3 \n"
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"1: bnez %0, 1b \n"
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" subu %0, 1 \n"
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" .set reorder \n"
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: "=r" (loops)
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: "0" (loops));
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}
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EXPORT_SYMBOL(__delay);
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/*
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* Division by multiplication: you don't have to worry about
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* loss of precision.
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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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void __udelay(unsigned long us)
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{
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unsigned int lpj = current_cpu_data.udelay_val;
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__delay((us * 0x000010c7 * HZ * lpj) >> 32);
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}
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EXPORT_SYMBOL(__udelay);
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void __ndelay(unsigned long ns)
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{
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unsigned int lpj = current_cpu_data.udelay_val;
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__delay((us * 0x00000005 * HZ * lpj) >> 32);
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}
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EXPORT_SYMBOL(__ndelay);
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