/* * 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. */ #ifndef _ASM_DELAY_H #define _ASM_DELAY_H #include <linux/config.h> #include <linux/param.h> #include <linux/smp.h> #include <asm/compiler.h> static inline void __delay(unsigned long loops) { if (sizeof(long) == 4) __asm__ __volatile__ ( ".set\tnoreorder\n" "1:\tbnez\t%0,1b\n\t" "subu\t%0,1\n\t" ".set\treorder" : "=r" (loops) : "0" (loops)); else if (sizeof(long) == 8) __asm__ __volatile__ ( ".set\tnoreorder\n" "1:\tbnez\t%0,1b\n\t" "dsubu\t%0,1\n\t" ".set\treorder" :"=r" (loops) :"0" (loops)); } /* * 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) */ static inline void __udelay(unsigned long usecs, unsigned long lpj) { unsigned long lo; /* * The rates of 128 is rounded wrongly by the catchall case * for 64-bit. Excessive precission? Probably ... */ #if defined(CONFIG_64BIT) && (HZ == 128) usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */ #elif defined(CONFIG_64BIT) usecs *= (0x8000000000000000UL / (500000 / HZ)); #else /* 32-bit junk follows here */ usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) + 0x80000000ULL) >> 32); #endif if (sizeof(long) == 4) __asm__("multu\t%2, %3" : "=h" (usecs), "=l" (lo) : "r" (usecs), "r" (lpj) : GCC_REG_ACCUM); else if (sizeof(long) == 8) __asm__("dmultu\t%2, %3" : "=h" (usecs), "=l" (lo) : "r" (usecs), "r" (lpj) : GCC_REG_ACCUM); __delay(usecs); } #define __udelay_val cpu_data[smp_processor_id()].udelay_val #define udelay(usecs) __udelay((usecs),__udelay_val) /* make sure "usecs *= ..." in udelay do not overflow. */ #if HZ >= 1000 #define MAX_UDELAY_MS 1 #elif HZ <= 200 #define MAX_UDELAY_MS 5 #else #define MAX_UDELAY_MS (1000 / HZ) #endif #endif /* _ASM_DELAY_H */