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

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

[Andres Salomon]

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

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

[Alan Cox]

On Wed, 9 Apr 2008 22:33:28 -0400
Andres Salomon <dilinger@queued.net> wrote:

> 
> 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.

NAK - but minor

This is a check for *VSA2* which is not the same as VSA1 (Cyrix one) and
for older systems that actually matters as you may have VSA1 or VSA2 and
they are detected differently.

> +/* VSA magic values */

These should be VSA2 I think

> +static inline int geode_has_vsa(void)

has_vsa2


Alan (Keeper of the ancient cyrix docs ;))

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

[Andres Salomon]

On Thu, 10 Apr 2008 09:10:57 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Wed, 9 Apr 2008 22:33:28 -0400
> Andres Salomon <dilinger@queued.net> wrote:
> 
> > 
> > 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.
> 
> NAK - but minor
> 
> This is a check for *VSA2* which is not the same as VSA1 (Cyrix one) and
> for older systems that actually matters as you may have VSA1 or VSA2 and
> they are detected differently.
>

Excellent point.  Can we extend this to check for a VSA1-specific
string, or does VSA1 not have a similar signature?




 
> > +/* VSA magic values */
> 
> These should be VSA2 I think
> 
> > +static inline int geode_has_vsa(void)
> 
> has_vsa2
> 
> 
> Alan (Keeper of the ancient cyrix docs ;))

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

[Alan Cox]

> > This is a check for *VSA2* which is not the same as VSA1 (Cyrix one) and
> > for older systems that actually matters as you may have VSA1 or VSA2 and
> > they are detected differently.
> >
> 
> Excellent point.  Can we extend this to check for a VSA1-specific
> string, or does VSA1 not have a similar signature?

VSA1 requires you grovelling around poking at the video registers to get
a reliable answer and the only bits we need it for are the DMA bug (where
we assume all have it) and the sound driver (which uses the PCI space to
see what audio setup is there).

X cares but we don't currently.

Re: x86: GEODE: add Virtual Systems Architecture detection

[Jordan Crouse]

On 10/04/08 09:40 -0400, Andres Salomon wrote:
> On Thu, 10 Apr 2008 09:10:57 +0100
> Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> 
> > On Wed, 9 Apr 2008 22:33:28 -0400
> > Andres Salomon <dilinger@queued.net> wrote:
> > 
> > > 
> > > 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.
> > 
> > NAK - but minor
> > 
> > This is a check for *VSA2* which is not the same as VSA1 (Cyrix one) and
> > for older systems that actually matters as you may have VSA1 or VSA2 and
> > they are detected differently.
> >
> 
> Excellent point.  Can we extend this to check for a VSA1-specific
> string, or does VSA1 not have a similar signature?

I don't think we need to worry about it.  99.99% of Geode systems run
with VSA happily transparent in the background, and thus would have no
good reason to check for it.  Certainly, there are no processors with VSA1
that would care to check.

But Alan does have a good point - we should name it vsa2 for 
strict correctness.

Jordan
-- 
Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.

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

[Andres Salomon]

On Thu, 10 Apr 2008 15:20:19 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> > > This is a check for *VSA2* which is not the same as VSA1 (Cyrix one) and
> > > for older systems that actually matters as you may have VSA1 or VSA2 and
> > > they are detected differently.
> > >
> > 
> > Excellent point.  Can we extend this to check for a VSA1-specific
> > string, or does VSA1 not have a similar signature?
> 
> VSA1 requires you grovelling around poking at the video registers to get
> a reliable answer and the only bits we need it for are the DMA bug (where
> we assume all have it) and the sound driver (which uses the PCI space to
> see what audio setup is there).
> 
> X cares but we don't currently.

How about this?





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>
---
 include/asm-x86/geode.h |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/include/asm-x86/geode.h b/include/asm-x86/geode.h
index c208398..6cded63 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
 
+/* 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 @@ 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);
+}
+
 /* MFGPTs */
 
 #define MFGPT_MAX_TIMERS	8
-- 
1.5.4.2