From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Maciej W. Rozycki" <macro@linux-mips.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH -tip] x86: apic LVTT - use APIC_DIVISOR on 64bit mode
Date: Wed, 9 Jul 2008 23:02:37 +0400 [thread overview]
Message-ID: <20080709190237.GA21423@asus> (raw)
We use APIC_TDR_DIV_16 while setting APIC_TDCR (divisor)
it happened this moment is hidden from __setup_APIC_LVTT
caller. So we better increment caller 'clocks' value to
not change current behaviour and use APIC_DIVISOR
(as already done in 32bit version).
The main benefit - unified procedure code for 32/64bit modes.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
CC: "Maciej W. Rozycki" <macro@linux-mips.org>
---
Please review carefully. Any comments are welcome.
I'm _not_ 100% sure if this patch is safe.
Index: linux-2.6.git/arch/x86/kernel/apic_64.c
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/apic_64.c 2008-07-08 22:52:24.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/apic_64.c 2008-07-08 23:00:24.000000000 +0400
@@ -165,6 +165,9 @@ int lapic_get_maxlvt(void)
return maxlvt;
}
+/* Clock divisor is set to 16 */
+#define APIC_DIVISOR 16
+
/*
* This function sets up the local APIC timer, with a timeout of
* 'clocks' APIC bus clock. During calibration we actually call
@@ -197,7 +200,7 @@ static void __setup_APIC_LVTT(unsigned i
| APIC_TDR_DIV_16);
if (!oneshot)
- apic_write(APIC_TMICT, clocks);
+ apic_write(APIC_TMICT, clocks/APIC_DIVISOR);
}
/*
@@ -329,7 +332,7 @@ static void __init calibrate_APIC_clock(
*
* No interrupt enable !
*/
- __setup_APIC_LVTT(250000000, 0, 0);
+ __setup_APIC_LVTT(4000000000, 0, 0);
apic_start = apic_read(APIC_TMCCT);
#ifdef CONFIG_X86_PM_TIMER
next reply other threads:[~2008-07-09 19:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-09 19:02 Cyrill Gorcunov [this message]
2008-07-12 6:05 ` [PATCH -tip] x86: apic LVTT - use APIC_DIVISOR on 64bit mode Ingo Molnar
2008-07-12 7:22 ` Cyrill Gorcunov
2008-07-12 7:39 ` Ingo Molnar
2008-07-12 7:43 ` Cyrill Gorcunov
2008-07-12 7:37 ` Ingo Molnar
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