From e6536c1262c56d302e749ab1b44fdb0b9786327d Mon Sep 17 00:00:00 2001
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Date: Thu, 7 Dec 2006 02:14:07 +0100
Subject: [PATCH] [PATCH] x86: comment magic constants in delay.h
For both i386 and x86_64, copy from arch/$ARCH/lib/delay.c comments about the
used magic constants, plus a few other niceties.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andi Kleen <ak@suse.de>
include/asm-i386/delay.h | 5 ++++-
include/asm-x86_64/delay.h | 5 ++++-
2 files changed, 8 insertions(+), 2 deletions(-)
---
include/asm-i386/delay.h | 5 ++++-
include/asm-x86_64/delay.h | 5 ++++-
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/asm-i386/delay.h b/include/asm-i386/delay.h
index b1c7650dc7b9..9ae5e3782ed8 100644
--- a/include/asm-i386/delay.h
+++ b/include/asm-i386/delay.h
@@ -7,6 +7,7 @@
* Delay routines calling functions in arch/i386/lib/delay.c
*/
+/* Undefined functions to get compile-time errors */
extern void __bad_udelay(void);
extern void __bad_ndelay(void);
@@ -15,10 +16,12 @@ extern void __ndelay(unsigned long nsecs);
extern void __const_udelay(unsigned long usecs);
extern void __delay(unsigned long loops);
+/* 0x10c7 is 2**32 / 1000000 (rounded up) */
#define udelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
__udelay(n))
-
+
+/* 0x5 is 2**32 / 1000000000 (rounded up) */
#define ndelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
__ndelay(n))
diff --git a/include/asm-x86_64/delay.h b/include/asm-x86_64/delay.h
index 40146f611ccb..c2669f1f5529 100644
--- a/include/asm-x86_64/delay.h
+++ b/include/asm-x86_64/delay.h
@@ -7,18 +7,21 @@
* Delay routines calling functions in arch/x86_64/lib/delay.c
*/
+/* Undefined functions to get compile-time errors */
extern void __bad_udelay(void);
extern void __bad_ndelay(void);
extern void __udelay(unsigned long usecs);
-extern void __ndelay(unsigned long usecs);
+extern void __ndelay(unsigned long nsecs);
extern void __const_udelay(unsigned long usecs);
extern void __delay(unsigned long loops);
+/* 0x10c7 is 2**32 / 1000000 (rounded up) */
#define udelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
__udelay(n))
+/* 0x5 is 2**32 / 1000000000 (rounded up) */
#define ndelay(n) (__builtin_constant_p(n) ? \
((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
__ndelay(n))
--
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