diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-m68knommu/delay.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-m68knommu/delay.h')
-rw-r--r-- | include/asm-m68knommu/delay.h | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/include/asm-m68knommu/delay.h b/include/asm-m68knommu/delay.h new file mode 100644 index 000000000000..e3a976254672 --- /dev/null +++ b/include/asm-m68knommu/delay.h | |||
@@ -0,0 +1,76 @@ | |||
1 | #ifndef _M68KNOMMU_DELAY_H | ||
2 | #define _M68KNOMMU_DELAY_H | ||
3 | |||
4 | /* | ||
5 | * Copyright (C) 1994 Hamish Macdonald | ||
6 | * Copyright (C) 2004 Greg Ungerer <gerg@snapgear.com> | ||
7 | */ | ||
8 | |||
9 | #include <asm/param.h> | ||
10 | |||
11 | extern __inline__ void __delay(unsigned long loops) | ||
12 | { | ||
13 | #if defined(CONFIG_COLDFIRE) | ||
14 | /* The coldfire runs this loop at significantly different speeds | ||
15 | * depending upon long word alignment or not. We'll pad it to | ||
16 | * long word alignment which is the faster version. | ||
17 | * The 0x4a8e is of course a 'tstl %fp' instruction. This is better | ||
18 | * than using a NOP (0x4e71) instruction because it executes in one | ||
19 | * cycle not three and doesn't allow for an arbitary delay waiting | ||
20 | * for bus cycles to finish. Also fp/a6 isn't likely to cause a | ||
21 | * stall waiting for the register to become valid if such is added | ||
22 | * to the coldfire at some stage. | ||
23 | */ | ||
24 | __asm__ __volatile__ ( ".balignw 4, 0x4a8e\n\t" | ||
25 | "1: subql #1, %0\n\t" | ||
26 | "jcc 1b" | ||
27 | : "=d" (loops) : "0" (loops)); | ||
28 | #else | ||
29 | __asm__ __volatile__ ( "1: subql #1, %0\n\t" | ||
30 | "jcc 1b" | ||
31 | : "=d" (loops) : "0" (loops)); | ||
32 | #endif | ||
33 | } | ||
34 | |||
35 | /* | ||
36 | * Ideally we use a 32*32->64 multiply to calculate the number of | ||
37 | * loop iterations, but the older standard 68k and ColdFire do not | ||
38 | * have this instruction. So for them we have a clsoe approximation | ||
39 | * loop using 32*32->32 multiplies only. This calculation based on | ||
40 | * the ARM version of delay. | ||
41 | * | ||
42 | * We want to implement: | ||
43 | * | ||
44 | * loops = (usecs * 0x10c6 * HZ * loops_per_jiffy) / 2^32 | ||
45 | */ | ||
46 | |||
47 | #define HZSCALE (268435456 / (1000000/HZ)) | ||
48 | |||
49 | extern unsigned long loops_per_jiffy; | ||
50 | |||
51 | extern __inline__ void _udelay(unsigned long usecs) | ||
52 | { | ||
53 | #if defined(CONFIG_M68328) || defined(CONFIG_M68EZ328) || \ | ||
54 | defined(CONFIG_M68VZ328) || defined(CONFIG_M68360) || \ | ||
55 | defined(CONFIG_COLDFIRE) | ||
56 | __delay((((usecs * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6); | ||
57 | #else | ||
58 | unsigned long tmp; | ||
59 | |||
60 | usecs *= 4295; /* 2**32 / 1000000 */ | ||
61 | __asm__ ("mulul %2,%0:%1" | ||
62 | : "=d" (usecs), "=d" (tmp) | ||
63 | : "d" (usecs), "1" (loops_per_jiffy*HZ)); | ||
64 | __delay(usecs); | ||
65 | #endif | ||
66 | } | ||
67 | |||
68 | /* | ||
69 | * Moved the udelay() function into library code, no longer inlined. | ||
70 | * I had to change the algorithm because we are overflowing now on | ||
71 | * the faster ColdFire parts. The code is a little biger, so it makes | ||
72 | * sense to library it. | ||
73 | */ | ||
74 | extern void udelay(unsigned long usecs); | ||
75 | |||
76 | #endif /* defined(_M68KNOMMU_DELAY_H) */ | ||