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#ifndef _M68KNOMMU_DELAY_H
#define _M68KNOMMU_DELAY_H
/*
* Copyright (C) 1994 Hamish Macdonald
* Copyright (C) 2004 Greg Ungerer <gerg@snapgear.com>
*/
#include <asm/param.h>
static inline void __delay(unsigned long loops)
{
#if defined(CONFIG_COLDFIRE)
/* The coldfire runs this loop at significantly different speeds
* depending upon long word alignment or not. We'll pad it to
* long word alignment which is the faster version.
* The 0x4a8e is of course a 'tstl %fp' instruction. This is better
* than using a NOP (0x4e71) instruction because it executes in one
* cycle not three and doesn't allow for an arbitary delay waiting
* for bus cycles to finish. Also fp/a6 isn't likely to cause a
* stall waiting for the register to become valid if such is added
* to the coldfire at some stage.
*/
__asm__ __volatile__ ( ".balignw 4, 0x4a8e\n\t"
"1: subql #1, %0\n\t"
"jcc 1b"
: "=d" (loops) : "0" (loops));
#else
__asm__ __volatile__ ( "1: subql #1, %0\n\t"
"jcc 1b"
: "=d" (loops) : "0" (loops));
#endif
}
/*
* Ideally we use a 32*32->64 multiply to calculate the number of
* loop iterations, but the older standard 68k and ColdFire do not
* have this instruction. So for them we have a clsoe approximation
* loop using 32*32->32 multiplies only. This calculation based on
* the ARM version of delay.
*
* We want to implement:
*
* loops = (usecs * 0x10c6 * HZ * loops_per_jiffy) / 2^32
*/
#define HZSCALE (268435456 / (1000000/HZ))
extern unsigned long loops_per_jiffy;
static inline void _udelay(unsigned long usecs)
{
#if defined(CONFIG_M68328) || defined(CONFIG_M68EZ328) || \
defined(CONFIG_M68VZ328) || defined(CONFIG_M68360) || \
defined(CONFIG_COLDFIRE)
__delay((((usecs * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6);
#else
unsigned long tmp;
usecs *= 4295; /* 2**32 / 1000000 */
__asm__ ("mulul %2,%0:%1"
: "=d" (usecs), "=d" (tmp)
: "d" (usecs), "1" (loops_per_jiffy*HZ));
__delay(usecs);
#endif
}
/*
* Moved the udelay() function into library code, no longer inlined.
* I had to change the algorithm because we are overflowing now on
* the faster ColdFire parts. The code is a little biger, so it makes
* sense to library it.
*/
extern void udelay(unsigned long usecs);
#endif /* defined(_M68KNOMMU_DELAY_H) */
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