topic Re: SGMII MAC to MAC connection in Layerscape

SGMII MAC to MAC connection

michael_roeder — Fri, 22 Jan 2016 19:28:51 GMT

Hi,

I would like to directly connect two QorIQ (LS1) Processors through their SGMII MACs, same as a

point to point ethernet connection, just without using a PHY.

Theoretically, this should be possible by crossing RX/TX lanes and the other signals, respectively.

Has anybody ever attempted to do this, with or without success? Anything to take care of in the

MAC configuration? How should these MACs be entered in the device tree?

thanks in advance,

Michael

Re: SGMII MAC to MAC connection

lunminliang — Fri, 29 Jan 2016 08:00:21 GMT

Hello Michael Roeder,

I am not aware of anyone trying on LS1 processors, there're such implementation on PA based processors.

There is FTF PPT by our engineer touched on this, which is available from:

https://www.nxp.com/webapp/Download?colCode=FTF12_NET_F0215PDF&location=null&fsrch=1&sr=2&pageNum=1&Parent_nodeId=&Paren…

The basic ideas:

*May Lose external MDIO communication between the two MDC masters. Configuration and status info can be placed in system memory for access.

*Normal SGMII trace lengths should work up to 12". anything longer may need 1000Base-KX (which is not supported on any eTSEC based device even if it says it does).

*IBIS modeling is essential to confirm signal integrity across the interconnect.

Have a great day,
Lunmin

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Re: SGMII MAC to MAC connection

lunminliang — Mon, 01 Feb 2016 09:08:07 GMT

Hello Michael Roeder,

From the software, there is nothing to pay attention for MAC configuration.

In the device tree, you should use fixed-link. Something like:

&enet0 {

fixed-link = <1 1 1000 0 0>;

tbi-handle = <&tbi0>;

phy-connection-type = "sgmii";

status = "okay";

};

Have a great day,
Lunmin