x86: GEODE: add Virtual Systems Architecture detection
This is generic VSA2 detection. It's used by OLPC to determine whether or not
the BIOS contains VSA2, 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>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-x86/geode.h b/include/asm-x86/geode.h
index b1bdf63..3978200 100644
--- a/include/asm-x86/geode.h
+++ b/include/asm-x86/geode.h
@@ -103,6 +103,14 @@
#define PM_AWKD 0x50
#define PM_SSC 0x54
+/* VSA2 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 +182,17 @@
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);
+}
+
/* MFGPTs */
#define MFGPT_MAX_TIMERS 8