linux-kernel - [PATCH] x86: GEODE: cache results from geode_has

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Message-ID: <20080429013213.4084e892@ephemeral>
Date:	Tue, 29 Apr 2008 01:32:13 -0400
From:	Andres Salomon <dilinger@...ued.net>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
	linux-kernel@...r.kernel.org, jordan.crouse@....com
Subject: [PATCH] x86: GEODE: cache results from geode_has_vsa2() and
 uninline

On Mon, 28 Apr 2008 20:06:51 -0700
Andrew Morton <akpm@...ux-foundation.org> wrote:

> On Mon, 21 Apr 2008 17:02:30 -0400 Andres Salomon <dilinger@...ued.net> wrote:
> 
> > +	if (!is_geode() || geode_has_vsa2())
> 
> geode_has_vsa2() is a fairly expensive-looking function and afacit only
> needs to be evaluated once per boot.  Perhaps we should cache it somewhere?
> 

How about this?






This moves geode_has_vsa2 into a .c file, caches the result we get from
the VSA virtual registers, and causes the function to no longer be inline.

Signed-off-by: Andres Salomon <dilinger@...ian.org>
---
 arch/x86/kernel/geode_32.c |   19 +++++++++++++++++++
 include/asm-x86/geode.h    |   11 +----------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/geode_32.c b/arch/x86/kernel/geode_32.c
index 9dad6ca..1cb8225 100644
--- a/arch/x86/kernel/geode_32.c
+++ b/arch/x86/kernel/geode_32.c
@@ -161,6 +161,25 @@ void geode_gpio_setup_event(unsigned int gpio, int pair, int pme)
 }
 EXPORT_SYMBOL_GPL(geode_gpio_setup_event);
 
+static int has_vsa2 = -1;
+
+int geode_has_vsa2(void)
+{
+	if (has_vsa2 == -1) {
+		/*
+		 * The VSA has virtual registers that we can query for a
+		 * signature.
+		 */
+		outw(VSA_VR_UNLOCK, VSA_VRC_INDEX);
+		outw(VSA_VR_SIGNATURE, VSA_VRC_INDEX);
+
+		has_vsa2 = (inw(VSA_VRC_DATA) == VSA_SIG);
+	}
+
+	return has_vsa2;
+}
+EXPORT_SYMBOL_GPL(geode_has_vsa2);
+
 static int __init geode_southbridge_init(void)
 {
 	if (!is_geode())
diff --git a/include/asm-x86/geode.h b/include/asm-x86/geode.h
index 7154dc4..8a53bc8 100644
--- a/include/asm-x86/geode.h
+++ b/include/asm-x86/geode.h
@@ -185,16 +185,7 @@ static inline int is_geode(void)
 	return (is_geode_gx() || is_geode_lx());
 }
 
-/*
- * The VSA has virtual registers that we can query for a signature.
- */
-static inline int geode_has_vsa2(void)
-{
-	outw(VSA_VR_UNLOCK, VSA_VRC_INDEX);
-	outw(VSA_VR_SIGNATURE, VSA_VRC_INDEX);
-
-	return (inw(VSA_VRC_DATA) == VSA_SIG);
-}
+extern int geode_has_vsa2(void);
 
 /* MFGPTs */
 
-- 
1.5.5

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