ZynqMP PS-GTR 1000BASE-KX or SGMII

[ranjeet1]

Most Xilinx application notes and answer records show PS-GTR SGMII connected to a PHY (Marvell, TI etc.), and not directly to an SFP+ cage. Could you confirm that connecting a PS-GTR in SGMII mode to an SFP+ cage is a supported use case for the Zynq Ultrascale+ GEM?

The reason I’m asking is because:

1. lwip supports all ZynqMP configurations except for PS-GTR SGMII [2], and
2. We’ve run into a critical issue with PS-GTR SGMII interface on our ZU19EG board where no data seems to be transmitted or received by the ZU19EG device.

 On our board, GEM1 is configured to use GTLane1 which is routed to an SFP+ cage. An SFP+ cable connects this board to a D-Link switch that also has an SFP+ port. I’ve made the appropriate changes as suggested on Xilinx wiki pages [1], but unable to send or receive any packets, see attached pdf document.

[1]

http://www.wiki.xilinx.com/Macb+Driver
http://www.wiki.xilinx.com/Zynq+Ultrascale+Fixed+Link+PS+Ethernet+Demo

[2]

http://www.wiki.xilinx.com/page/diff/Standalone+LWIP+library?v1=618935609&v2=623726507

 

[ranjeet1]

Note that our ultimate desire is implement a 1000BASE-KX link originating from ZU19EG PS-GTR and going across a backplane to an Ethernet Switch card in another slot.

[ranjeet1]

The FPGA on our board is a ZU19EG Engineering Sample XCZU19EG-1FFVC1760IES9820

Tools used for building images to test this link are Vivado 2017.2, Petalinux 2017.2

[mmcguirk]

Hi @ranjeet1-

      Unfortunately, 1000BASE-X is not supported on PS-GTR for ZU+ MPSoC. Please see the explanation here:

https://forums.xilinx.com/t5/Networking-and-Connectivity/Does-PS-GTR-support-1000BASE-X/td-p/770680

If you are able to connect the SFP module to the EMIO you can reference and follow the example using our PL IP on the Wiki:

http://www.wiki.xilinx.com/PS+and+PL+based+Ethernet+in+Zynq+MPSoC

Thanks,

Michael

[ranjeet1]

Hi Michael,

Thanks for the quick response. I wanted to ask a follow up question - does the lack of support for 1000BASE-X also rule out any fixed-link connections like MAC to MAC GMII, or SGMII?

If you could provide some detail on which type of MAC to MAC connections are supported by GEM + PS-GTR combination that wo uld be very helpful. 

Thanks,

Ranjeet

http://www.wiki.xilinx.com/Macb+Driver#Devicetree-Related devicetree information

"-> This driver can be used for a MAC - MAC fixed link connection. In order to do so, please update the devicetree fixed link node as per
https://github.com/Xilinx/linux-xlnx/blob/master/Documentation/devicetree/bindings/net/fixed-link.txt
and set the phy-mode to "moca" (https://github.com/Xilinx/linux-xlnx/blob/master/include/linux/phy.h)"

[nanz · Accepted solution]

Hi @ranjeet1,

You can do the PS-GTR SGMII fixed link by using the attached patch. This is to enable SGMII initialization based on "is-internal-pcspma" DT property rather than "phy-mode".

[ranjeet1]

Hi @nanz, 

Thanks for providing the patch, we'll give it a try and let you know if we are able to get ethernet up and running using this patch.

Just to clarify, does the change involve following 2 steps?

1. Patch to macb driver as you provided in your message 

2. Device Tree (DT) modification to contain "is-internal-pcspma " and "phy-mode=moca"

Ranjeet

[nanz]

Hi @ranjeet1, Yes, this is correct.

[stephenm]

you can see how the DT is setup here for fixed link:

http://www.wiki.xilinx.com/Zynq+Ultrascale+Fixed+Link+PS+Ethernet+Demo