diff options
Diffstat (limited to 'arch/m68k/include/asm/delay.h')
-rw-r--r-- | arch/m68k/include/asm/delay.h | 97 |
1 files changed, 94 insertions, 3 deletions
diff --git a/arch/m68k/include/asm/delay.h b/arch/m68k/include/asm/delay.h index d2598e3dd7b..9c09becfd4c 100644 --- a/arch/m68k/include/asm/delay.h +++ b/arch/m68k/include/asm/delay.h @@ -1,5 +1,96 @@ -#ifdef __uClinux__ -#include "delay_no.h" +#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 -#include "delay_mm.h" +/* + * 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) */ |