2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 1994 by Waldorf Electronics
7 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
13 #include <linux/param.h>
14 #include <linux/smp.h>
15 #include <asm/compiler.h>
17 static inline void __delay(unsigned long loops)
19 if (sizeof(long) == 4)
20 __asm__ __volatile__ (
28 else if (sizeof(long) == 8)
29 __asm__ __volatile__ (
41 * Division by multiplication: you don't have to worry about
44 * Use only for very small delays ( < 1 msec). Should probably use a
45 * lookup table, really, as the multiplications take much too long with
46 * short delays. This is a "reasonable" implementation, though (and the
47 * first constant multiplications gets optimized away if the delay is
51 static inline void __udelay(unsigned long usecs, unsigned long lpj)
56 * The rates of 128 is rounded wrongly by the catchall case
57 * for 64-bit. Excessive precission? Probably ...
59 #if defined(CONFIG_64BIT) && (HZ == 128)
60 usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */
61 #elif defined(CONFIG_64BIT)
62 usecs *= (0x8000000000000000UL / (500000 / HZ));
63 #else /* 32-bit junk follows here */
64 usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) +
65 0x80000000ULL) >> 32);
68 if (sizeof(long) == 4)
69 __asm__("multu\t%2, %3"
70 : "=h" (usecs), "=l" (lo)
71 : "r" (usecs), "r" (lpj)
73 else if (sizeof(long) == 8)
74 __asm__("dmultu\t%2, %3"
75 : "=h" (usecs), "=l" (lo)
76 : "r" (usecs), "r" (lpj)
82 #define __udelay_val cpu_data[raw_smp_processor_id()].udelay_val
84 #define udelay(usecs) __udelay((usecs),__udelay_val)
86 /* make sure "usecs *= ..." in udelay do not overflow. */
88 #define MAX_UDELAY_MS 1
90 #define MAX_UDELAY_MS 5
92 #define MAX_UDELAY_MS (1000 / HZ)
95 #endif /* _ASM_DELAY_H */