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>
57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
/*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
* Copyright (C) 1994 by Waldorf Electronics
|
|
* Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
|
|
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
|
|
* Copyright (C) 2007 Maciej W. Rozycki
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/param.h>
|
|
#include <linux/smp.h>
|
|
|
|
#include <asm/compiler.h>
|
|
#include <asm/war.h>
|
|
|
|
inline void __delay(unsigned int loops)
|
|
{
|
|
__asm__ __volatile__ (
|
|
" .set noreorder \n"
|
|
" .align 3 \n"
|
|
"1: bnez %0, 1b \n"
|
|
" subu %0, 1 \n"
|
|
" .set reorder \n"
|
|
: "=r" (loops)
|
|
: "0" (loops));
|
|
}
|
|
EXPORT_SYMBOL(__delay);
|
|
|
|
/*
|
|
* 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)
|
|
*/
|
|
|
|
void __udelay(unsigned long us)
|
|
{
|
|
unsigned int lpj = current_cpu_data.udelay_val;
|
|
|
|
__delay((us * 0x000010c7 * HZ * lpj) >> 32);
|
|
}
|
|
EXPORT_SYMBOL(__udelay);
|
|
|
|
void __ndelay(unsigned long ns)
|
|
{
|
|
unsigned int lpj = current_cpu_data.udelay_val;
|
|
|
|
__delay((us * 0x00000005 * HZ * lpj) >> 32);
|
|
}
|
|
EXPORT_SYMBOL(__ndelay);
|