Linux/PROCESSOR-SDK-AM335X: VLAN configuration issue

Tim Potter

Tool/software: Linux

We are using TI SDK 7.0 with Linux 3.12.10.

We have not enabled VLAN support in the kernel. The 8021q support does get compiled but as a loadable module. This module is not loaded. Using WireShark we have seen that our ehternet packets have vlan tags added to it. This is causing issues when trying to communicate with some devices that do not support vlans. How do we disable this? We do not want vlan tags added to our packets.

An example is in this screen shot:

over 7 years ago

0 Brad Griffis over 7 years ago

TI__Guru*** 125430 points

Do you have one or two ethernet ports? Are you using the "dual_mac" property in your dts? Can you share a snippet from your dts showing your configuration?

0 Schuyler Patton over 7 years ago in reply to Brad Griffis

TI__Mastermind 40730 points

Hi,
The screen shot is not showing up. VLANs are used inside the ALE to assist which port a packet has ingressed or egressed and depend on the dual mac property that Brad mentions. Which VLAN tag Ids are you seeing in Wireshark?

Best Regards,
Schuyler

0 Tim Potter over 7 years ago in reply to Brad Griffis

Intellectual 726 points

Hi Brad,

Looked into the dts file. We do have dual_emacs

&cpsw_emac0 {
phy_id = <&davinci_mdio>, <1>;
phy-mode = "mii";
dual_emac_res_vlan = <1>;
};

&cpsw_emac1 {
phy_id = <&davinci_mdio>, <3>;
phy-mode = "mii";
dual_emac_res_vlan = <2>;
};

I see that item dual_emac_res_vlan, is that required? When we configure the ports we make sure they are each on an unique subnet so we don't need vlans.

0 Brad Griffis over 7 years ago in reply to Tim Potter

TI__Guru*** 125430 points

The use of VLANs is central to the dual_emac mode of operation:

processors.wiki.ti.com/.../Linux_Core_CPSW_User's_Guide

I don't think there's any way of avoiding it. I'm doing some further checking via email to see if anyone knows of any tricks that can be used here. Stay tuned.

0 Brad Griffis over 7 years ago in reply to Brad Griffis

TI__Guru*** 125430 points

Tim,

Is it only one of the ports that is emitting the VLAN tag on the network? Or do you see it from both?

Brad

0 Brad Griffis over 7 years ago in reply to Brad Griffis

TI__Guru*** 125430 points

Tim,

Here's a thread that sounds like the same issue you're describing. Can you try the patch? Here it is:

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 5d5fec6..6133e4a 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -1201,8 +1201,7 @@  static int cpsw_ndo_open(struct net_device *ndev)
 	for_each_slave(priv, cpsw_slave_open, priv);
 
 	/* Add default VLAN */
-	if (!priv->data.dual_emac)
-		cpsw_add_default_vlan(priv);
+	cpsw_add_default_vlan(priv);
 
 	if (!cpsw_common_res_usage_state(priv)) {
 		/* setup tx dma to fixed prio and zero offset */

Brad

0 Tim Potter over 7 years ago in reply to Brad Griffis

Intellectual 726 points

It is on both ports

0 Tim Potter over 7 years ago in reply to Brad Griffis

Intellectual 726 points

Thanks Brad. This patch seems to have resolved the problem.

Processors

Processors forum

Linux/PROCESSOR-SDK-AM335X: VLAN configuration issue