Re: [RFC net-next v2 0/6] ethtool: Generic loopback support
From: Andrew Lunn <andrew@lunn.ch>
Date: 2026-03-11 12:32:28
Also in:
linux-rdma, lkml
From: Andrew Lunn <andrew@lunn.ch>
Date: 2026-03-11 12:32:28
Also in:
linux-rdma, lkml
quoted
quoted
With a SERDES component, the mapping becomes cleaner: component name supported MAC mac near-end SERDES serdes-ned near-end SERDES serdes-nea near-end SERDES serdes-fed far-endIf Linux where to drive the SERDES, what part of Linux would it be? Generic PHY? How does your SERDES hardware block fit into 802.3? Which clause describes it?Hi Andrew, On OcteonTx2 SoC, the SerDes (GSERM) is a HW block integrated into the SoC die. It is not on an MDIO bus or any bus that Linux can enumerate. The block is fully managed by the firmware running on the SoC. The NIC driver configures it indirectly through firmware mailbox commands. The data path looks like: MAC (RPM) --- SerDes (GSERM) --- module/PHY In 802.3 terms, the closest match would be PMA. The GSERM handles serialization/deserialization and the analog front-end.
A Linux Generic PHY is probably also PMA.
802.3 says very little about SERDES, it is not a well defined term. So
i think we want PCS and PMA, not SERDES as a loopback point.
Andrew