[PATCH 2/3] x86: GEODE: add Virtual Systems Architecture detection

[Andres Salomon <dilinger@queued.net>]

This is generic VSA detection.  It's used by OLPC to determine whether or
not the BIOS contains VSA, but since other BIOSes are coming out that don't
use the VSA (ie, tinybios), it might end up being useful for others.

Signed-off-by: Andres Salomon <dilinger@debian.org>
---
 include/asm-x86/geode.h |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/include/asm-x86/geode.h b/include/asm-x86/geode.h
index c208398..882acf8 100644
--- a/include/asm-x86/geode.h
+++ b/include/asm-x86/geode.h
@@ -103,6 +103,14 @@ extern int geode_get_dev_base(unsigned int dev);
 #define PM_AWKD			0x50
 #define PM_SSC			0x54
 
+/* VSA magic values */
+
+#define VSA_VRC_INDEX		0xAC1C
+#define VSA_VRC_DATA		0xAC1E
+#define VSA_VR_UNLOCK		0xFC53	/* unlock virtual register */
+#define VSA_VR_SIGNATURE	0x0003
+#define VSA_SIG			0x4132	/* signature is ascii 'VSA2' */
+
 /* GPIO */
 
 #define GPIO_OUTPUT_VAL		0x00
@@ -174,6 +182,14 @@ static inline int is_geode(void)
 	return (is_geode_gx() || is_geode_lx());
 }
 
+static inline int geode_has_vsa(void)
+{
+	outw(VSA_VR_UNLOCK, VSA_VRC_INDEX);
+	outw(VSA_VR_SIGNATURE, VSA_VRC_INDEX);
+
+	return (inw(VSA_VRC_DATA) == VSA_SIG);
+}
+
 /* MFGPTs */
 
 #define MFGPT_MAX_TIMERS	8
-- 
1.5.4.2