* [PATCH] fix mdelay(1) for 64bit kernel with HZ == 1000
@ 2005-11-30 4:33 Atsushi Nemoto
2005-12-05 14:35 ` Ralf Baechle
0 siblings, 1 reply; 2+ messages in thread
From: Atsushi Nemoto @ 2005-11-30 4:33 UTC (permalink / raw)
To: linux-mips; +Cc: ralf
mdelay(1) (i.e. udelay(1000)) does not work correctly due to overflow.
1000 * 0x004189374BC6A7f0 = 0x10000000000000180 (>= 2**64)
0x004189374BC6A7ef (0x004189374BC6A7f0 - 1) is OK and it is exactly
same as catchall case (0x8000000000000000UL / (500000 / HZ)).
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
diff --git a/include/asm-mips/delay.h b/include/asm-mips/delay.h
index 48d00cc..64dd451 100644
--- a/include/asm-mips/delay.h
+++ b/include/asm-mips/delay.h
@@ -52,13 +52,11 @@ static inline void __udelay(unsigned lon
unsigned long lo;
/*
- * The common rates of 1000 and 128 are rounded wrongly by the
- * catchall case for 64-bit. Excessive precission? Probably ...
+ * The rates of 128 is rounded wrongly by the catchall case
+ * for 64-bit. Excessive precission? Probably ...
*/
#if defined(CONFIG_64BIT) && (HZ == 128)
usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */
-#elif defined(CONFIG_64BIT) && (HZ == 1000)
- usecs *= 0x004189374BC6A7f0UL; /* 2**64 / (1000000 / HZ) */
#elif defined(CONFIG_64BIT)
usecs *= (0x8000000000000000UL / (500000 / HZ));
#else /* 32-bit junk follows here */
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] fix mdelay(1) for 64bit kernel with HZ == 1000
2005-11-30 4:33 [PATCH] fix mdelay(1) for 64bit kernel with HZ == 1000 Atsushi Nemoto
@ 2005-12-05 14:35 ` Ralf Baechle
0 siblings, 0 replies; 2+ messages in thread
From: Ralf Baechle @ 2005-12-05 14:35 UTC (permalink / raw)
To: Atsushi Nemoto; +Cc: linux-mips
On Wed, Nov 30, 2005 at 01:33:26PM +0900, Atsushi Nemoto wrote:
> mdelay(1) (i.e. udelay(1000)) does not work correctly due to overflow.
>
> 1000 * 0x004189374BC6A7f0 = 0x10000000000000180 (>= 2**64)
>
> 0x004189374BC6A7ef (0x004189374BC6A7f0 - 1) is OK and it is exactly
> same as catchall case (0x8000000000000000UL / (500000 / HZ)).
>
> Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Applied.
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2005-12-05 14:36 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-11-30 4:33 [PATCH] fix mdelay(1) for 64bit kernel with HZ == 1000 Atsushi Nemoto
2005-12-05 14:35 ` Ralf Baechle
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.