diff options
Diffstat (limited to 'include/asm-mips/delay.h')
-rw-r--r-- | include/asm-mips/delay.h | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/include/asm-mips/delay.h b/include/asm-mips/delay.h new file mode 100644 index 000000000000..d0f68447e5a7 --- /dev/null +++ b/include/asm-mips/delay.h | |||
@@ -0,0 +1,93 @@ | |||
1 | /* | ||
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 | ||
4 | * for more details. | ||
5 | * | ||
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. | ||
9 | */ | ||
10 | #ifndef _ASM_DELAY_H | ||
11 | #define _ASM_DELAY_H | ||
12 | |||
13 | #include <linux/config.h> | ||
14 | #include <linux/param.h> | ||
15 | |||
16 | #include <asm/compiler.h> | ||
17 | |||
18 | extern unsigned long loops_per_jiffy; | ||
19 | |||
20 | static inline void __delay(unsigned long loops) | ||
21 | { | ||
22 | if (sizeof(long) == 4) | ||
23 | __asm__ __volatile__ ( | ||
24 | ".set\tnoreorder\n" | ||
25 | "1:\tbnez\t%0,1b\n\t" | ||
26 | "subu\t%0,1\n\t" | ||
27 | ".set\treorder" | ||
28 | : "=r" (loops) | ||
29 | : "0" (loops)); | ||
30 | else if (sizeof(long) == 8) | ||
31 | __asm__ __volatile__ ( | ||
32 | ".set\tnoreorder\n" | ||
33 | "1:\tbnez\t%0,1b\n\t" | ||
34 | "dsubu\t%0,1\n\t" | ||
35 | ".set\treorder" | ||
36 | :"=r" (loops) | ||
37 | :"0" (loops)); | ||
38 | } | ||
39 | |||
40 | |||
41 | /* | ||
42 | * Division by multiplication: you don't have to worry about | ||
43 | * loss of precision. | ||
44 | * | ||
45 | * Use only for very small delays ( < 1 msec). Should probably use a | ||
46 | * lookup table, really, as the multiplications take much too long with | ||
47 | * short delays. This is a "reasonable" implementation, though (and the | ||
48 | * first constant multiplications gets optimized away if the delay is | ||
49 | * a constant) | ||
50 | */ | ||
51 | |||
52 | static inline void __udelay(unsigned long usecs, unsigned long lpj) | ||
53 | { | ||
54 | unsigned long lo; | ||
55 | |||
56 | /* | ||
57 | * The common rates of 1000 and 128 are rounded wrongly by the | ||
58 | * catchall case for 64-bit. Excessive precission? Probably ... | ||
59 | */ | ||
60 | #if defined(CONFIG_MIPS64) && (HZ == 128) | ||
61 | usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */ | ||
62 | #elif defined(CONFIG_MIPS64) && (HZ == 1000) | ||
63 | usecs *= 0x004189374BC6A7f0UL; /* 2**64 / (1000000 / HZ) */ | ||
64 | #elif defined(CONFIG_MIPS64) | ||
65 | usecs *= (0x8000000000000000UL / (500000 / HZ)); | ||
66 | #else /* 32-bit junk follows here */ | ||
67 | usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) + | ||
68 | 0x80000000ULL) >> 32); | ||
69 | #endif | ||
70 | |||
71 | if (sizeof(long) == 4) | ||
72 | __asm__("multu\t%2, %3" | ||
73 | : "=h" (usecs), "=l" (lo) | ||
74 | : "r" (usecs), "r" (lpj) | ||
75 | : GCC_REG_ACCUM); | ||
76 | else if (sizeof(long) == 8) | ||
77 | __asm__("dmultu\t%2, %3" | ||
78 | : "=h" (usecs), "=l" (lo) | ||
79 | : "r" (usecs), "r" (lpj) | ||
80 | : GCC_REG_ACCUM); | ||
81 | |||
82 | __delay(usecs); | ||
83 | } | ||
84 | |||
85 | #ifdef CONFIG_SMP | ||
86 | #define __udelay_val cpu_data[smp_processor_id()].udelay_val | ||
87 | #else | ||
88 | #define __udelay_val loops_per_jiffy | ||
89 | #endif | ||
90 | |||
91 | #define udelay(usecs) __udelay((usecs),__udelay_val) | ||
92 | |||
93 | #endif /* _ASM_DELAY_H */ | ||