97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
#ifndef _M68K_DELAY_H
|
|
#define _M68K_DELAY_H
|
|
|
|
#include <asm/param.h>
|
|
|
|
/*
|
|
* Copyright (C) 1994 Hamish Macdonald
|
|
* Copyright (C) 2004 Greg Ungerer <gerg@uclinux.com>
|
|
*
|
|
* Delay routines, using a pre-computed "loops_per_jiffy" value.
|
|
*/
|
|
|
|
#if defined(CONFIG_COLDFIRE)
|
|
/*
|
|
* The ColdFire runs the delay 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 arbitrary 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.
|
|
*/
|
|
#define DELAY_ALIGN ".balignw 4, 0x4a8e\n\t"
|
|
#else
|
|
/*
|
|
* No instruction alignment required for other m68k types.
|
|
*/
|
|
#define DELAY_ALIGN
|
|
#endif
|
|
|
|
static inline void __delay(unsigned long loops)
|
|
{
|
|
__asm__ __volatile__ (
|
|
DELAY_ALIGN
|
|
"1: subql #1,%0\n\t"
|
|
"jcc 1b"
|
|
: "=d" (loops)
|
|
: "0" (loops));
|
|
}
|
|
|
|
extern void __bad_udelay(void);
|
|
|
|
|
|
#if defined(CONFIG_M68000) || defined(CONFIG_COLDFIRE)
|
|
/*
|
|
* The simpler m68k and ColdFire processors do not have a 32*32->64
|
|
* multiply instruction. So we need to handle them a little differently.
|
|
* We use a bit of shifting and a single 32*32->32 multiply to get close.
|
|
* This is a macro so that the const version can factor out the first
|
|
* multiply and shift.
|
|
*/
|
|
#define HZSCALE (268435456 / (1000000 / HZ))
|
|
|
|
#define __const_udelay(u) \
|
|
__delay(((((u) * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6)
|
|
|
|
#else
|
|
|
|
static inline void __xdelay(unsigned long xloops)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
__asm__ ("mulul %2,%0:%1"
|
|
: "=d" (xloops), "=d" (tmp)
|
|
: "d" (xloops), "1" (loops_per_jiffy));
|
|
__delay(xloops * HZ);
|
|
}
|
|
|
|
/*
|
|
* The definition of __const_udelay is specifically made a macro so that
|
|
* the const factor (4295 = 2**32 / 1000000) can be optimized out when
|
|
* the delay is a const.
|
|
*/
|
|
#define __const_udelay(n) (__xdelay((n) * 4295))
|
|
|
|
#endif
|
|
|
|
static inline void __udelay(unsigned long usecs)
|
|
{
|
|
__const_udelay(usecs);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
*/
|
|
#define udelay(n) (__builtin_constant_p(n) ? \
|
|
((n) > 20000 ? __bad_udelay() : __const_udelay(n)) : __udelay(n))
|
|
|
|
|
|
#endif /* defined(_M68K_DELAY_H) */
|