[PATCH] net: dsa: allow XAUI phy interface mode

[PATCH] net: dsa: allow XAUI phy interface mode

[Russell King]

XGMII is a 32-bit bus plus two clock signals per direction.  XAUI is
four serial lanes per direction.  The 88e6190 supports XAUI but not
XGMII as it doesn't have enough pins.  The same is true of 88e6176.

Match on PHY_INTERFACE_MODE_XAUI for the XAUI port type, but keep
accepting XGMII for backwards compatibility.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/dsa/mv88e6xxx/port.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index a7801f6668a5..6315774d72b3 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -338,6 +338,7 @@ int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 		cmode = MV88E6XXX_PORT_STS_CMODE_2500BASEX;
 		break;
 	case PHY_INTERFACE_MODE_XGMII:
+	case PHY_INTERFACE_MODE_XAUI:
 		cmode = MV88E6XXX_PORT_STS_CMODE_XAUI;
 		break;
 	case PHY_INTERFACE_MODE_RXAUI:
-- 
2.7.4

Re: [PATCH] net: dsa: allow XAUI phy interface mode

[Andrew Lunn]

On Fri, Dec 08, 2017 at 04:04:59PM +0000, Russell King wrote:
> XGMII is a 32-bit bus plus two clock signals per direction.  XAUI is
> four serial lanes per direction.  The 88e6190 supports XAUI but not
> XGMII as it doesn't have enough pins.  The same is true of 88e6176.
> 
> Match on PHY_INTERFACE_MODE_XAUI for the XAUI port type, but keep
> accepting XGMII for backwards compatibility.

Hi Russell

The backwards compatibility is for the ZII devel C, the DSA link
between the two switches? I don't think there are any other boards
using this.

I will ask around, but i don't think we need to worry about backwards
compatibility. There is no region of flash set aside for the DT blob,
etc. I always TFTP boot using the one from the kernel, etc.

  Andrew

Re: [PATCH] net: dsa: allow XAUI phy interface mode

[Russell King - ARM Linux]

On Fri, Dec 08, 2017 at 05:26:43PM +0100, Andrew Lunn wrote:
> On Fri, Dec 08, 2017 at 04:04:59PM +0000, Russell King wrote:
> > XGMII is a 32-bit bus plus two clock signals per direction.  XAUI is
> > four serial lanes per direction.  The 88e6190 supports XAUI but not
> > XGMII as it doesn't have enough pins.  The same is true of 88e6176.
> > 
> > Match on PHY_INTERFACE_MODE_XAUI for the XAUI port type, but keep
> > accepting XGMII for backwards compatibility.
> 
> Hi Russell
> 
> The backwards compatibility is for the ZII devel C, the DSA link
> between the two switches? I don't think there are any other boards
> using this.
> 
> I will ask around, but i don't think we need to worry about backwards
> compatibility. There is no region of flash set aside for the DT blob,
> etc. I always TFTP boot using the one from the kernel, etc.

Well, there's also kexec to consider, where it's better not to specify
the --dtb option because that wipes out the modifications (such as the
memory information) that the boot loader made to the pristine kbuild
generated dtb.  So, with kexec its preferable to use the existing dtb
even with a newer kernel, or if not go through a full reboot to use a
new dtb.

Whether anyone uses kexec on this platform though would be an entirely
separate question, but I'm generally not in favour of breaking
compatibility with already merged DT without good reason.

You do seem to be correct that this only applies (in mainline) to the
ZII rev C board, so I guess including a patch to update its dts for
the inter-switch connection would at least be sensible.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
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Re: [PATCH] net: dsa: allow XAUI phy interface mode

[Andrew Lunn]

> You do seem to be correct that this only applies (in mainline) to the
> ZII rev C board, so I guess including a patch to update its dts for
> the inter-switch connection would at least be sensible.

Hi Russell

So lets have the backward compatible for a couple of kernel cycles,
and modify ZII rev now to use the correct mode.

    Andrew

Re: [PATCH] net: dsa: allow XAUI phy interface mode

[David Miller]

From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Fri, 08 Dec 2017 16:04:59 +0000

> XGMII is a 32-bit bus plus two clock signals per direction.  XAUI is
> four serial lanes per direction.  The 88e6190 supports XAUI but not
> XGMII as it doesn't have enough pins.  The same is true of 88e6176.
> 
> Match on PHY_INTERFACE_MODE_XAUI for the XAUI port type, but keep
> accepting XGMII for backwards compatibility.
> 
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Based upon the discussion of this patch I am expecting to receive
a DT patch that replaces this one, and some time in the future the
XGMII case statement providing backwards compatibility will be
removed.

Please let me know if this is not the case.

THanks.

Re: [PATCH] net: dsa: allow XAUI phy interface mode

[Russell King - ARM Linux]

On Mon, Dec 11, 2017 at 01:54:03PM -0500, David Miller wrote:
> From: Russell King <rmk+kernel@armlinux.org.uk>
> Date: Fri, 08 Dec 2017 16:04:59 +0000
> 
> > XGMII is a 32-bit bus plus two clock signals per direction.  XAUI is
> > four serial lanes per direction.  The 88e6190 supports XAUI but not
> > XGMII as it doesn't have enough pins.  The same is true of 88e6176.
> > 
> > Match on PHY_INTERFACE_MODE_XAUI for the XAUI port type, but keep
> > accepting XGMII for backwards compatibility.
> > 
> > Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> 
> Based upon the discussion of this patch I am expecting to receive
> a DT patch that replaces this one, and some time in the future the
> XGMII case statement providing backwards compatibility will be
> removed.
> 
> Please let me know if this is not the case.

That's something like it - asked Andrew via IRC on Saturday:

Do we want to do the XAUI thing as one patch to avoid any breakage, and
if so via whom?

and haven't had a response.  Normally arm-soc folk want patches
touching arch/arm/boot/dts to go via their tree.

So, until I know what to do, I can't proceed with this... and I've
soo many outstanding net patches now that I'm losing track of where
each patch I've sent out is.  Sorry, I'm failing.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
According to speedtest.net: 8.21Mbps down 510kbps up

Re: [PATCH] net: dsa: allow XAUI phy interface mode

[Andrew Lunn]

> That's something like it - asked Andrew via IRC on Saturday:
> 
> Do we want to do the XAUI thing as one patch to avoid any breakage, and
> if so via whom?

Hi Russell

Sorry for not replying. I was on a plane by then.

> and haven't had a response.  Normally arm-soc folk want patches
> touching arch/arm/boot/dts to go via their tree.
> 
> So, until I know what to do, I can't proceed with this... and I've
> soo many outstanding net patches now that I'm losing track of where
> each patch I've sent out is.  Sorry, I'm failing.

I would put both patches via netdev, to avoid breakage. We have done
this before for the ZII devel board, with the imx maintainers ACK.  I
don't expect any clashes in the DT file. The 10Gb port might be added
soon, but i think there is enough separation in the changes they won't
result in a conflict if they take a different path.

Do you want me to send a v2, with the additional DT patch?

   Thanks
	Andrew