diff options
Diffstat (limited to 'include/asm-mips64/delay.h')
| -rw-r--r-- | include/asm-mips64/delay.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/include/asm-mips64/delay.h b/include/asm-mips64/delay.h new file mode 100644 index 000000000..f3ec30a9e --- /dev/null +++ b/include/asm-mips64/delay.h @@ -0,0 +1,54 @@ +/* $Id$ + * + * 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 - 1999 by Ralf Baechle + * Copyright (C) 1999 Silicon Graphics, Inc. + */ +#ifndef _ASM_DELAY_H +#define _ASM_DELAY_H + +extern __inline__ void +__delay(unsigned long loops) +{ + __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) + */ +extern __inline__ void __udelay(unsigned long usecs, unsigned long lps) +{ + usecs *= 0x000010c6f7a0b5edUL; /* 2**64 / 1000000 */ + __asm__("dmultu\t%0,%2\n\t" + "mfhi\t%0" + :"=r" (usecs) + :"0" (usecs),"r" (lps)); + __delay(usecs); +} + +#ifdef __SMP__ +#define __udelay_val cpu_data[smp_processor_id()].udelay_val +#else +#define __udelay_val loops_per_sec +#endif + +#define udelay(usecs) __udelay((usecs),__udelay_val) + +#endif /* _ASM_DELAY_H */ |