#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 bigger, so it makes * sense to library it. */ extern void udelay(unsigned long usecs); #endif /* defined(_M68KNOMMU_DELAY_H) */