Re: [PATCH net-next v9 00/10] net: phy_port: SFP modules representation and phy_port listing

[Paolo Abeni <pabeni@redhat.com>]

On 4/3/26 2:37 PM, Maxime Chevallier wrote:
> Hello everyone,
> 
> Here's V9 for the phy_port netlink interface (get-only for now).
> 
> V9 addresses sashiko's issues (not all of them, as some don't make
> sense), and updates the missings parts in the doc.
> 
> This work extends on the recent addition of phy_port representation to enable
> listing the front-facing ports of an interface. For now, we don't control
> these ports, we merely list their presence and their capabilities.
> 
> As the most common use-case of multi-port interfaces is combo-ports that
> provide both RJ45 and SFP connectors on a single MAC, there's a lot of
> SFP stuff in this series.
> 
> This series is in 2 main parts. The first one aims at representing the
> SFP cages and modules using phy_port, as combo-ports with RJ45 + SFP are
> by far the most common cases for multi-connector setups.
> 
> The second part is the netlink interface to list those ports, now that
> most use-cases are covered.
> 
> Let's see what we can do with some examples of the new ethtool API :
> 
> - Get MII interfaces supported by an empty SFP cage :
> 
> # ethtool --show-ports eth3
> 
> Port for eth3:
> 	Port id: 1
> 	Vacant: yes
> 	Supported MII interfaces : sgmii, 1000base-x, 2500base-x
> 	Port type: sfp
> 
> - Get Combo-ports supported modes, on each port :
> 
> # ethtool --show-ports eth1
> 
> Port for eth1:
> 	Port id: 1
> 	Vacant: no
> 	Supported link modes:  10baseT/Half 10baseT/Full
> 	                       100baseT/Half 100baseT/Full
> 	                       1000baseT/Full
> 	                       10000baseT/Full
> 	                       2500baseT/Full
> 	                       5000baseT/Full
> 
> 	Port type: mdi
> 
> Port for eth1:
> 	Port id: 2
> 	Vacant: yes
> 	Supported MII interfaces : 10gbase-r
> 	Port type: sfp
> 
> - Get Achievable linkmodes on a SFP module (combo port with a DAC in the
> SFP cage)
> 
> # ethtool --show-ports eth1
> 
> Port for eth1:
> 	Port id: 1
> 	Vacant: no
> 	Supported link modes:  10baseT/Half 10baseT/Full
> 	                       100baseT/Half 100baseT/Full
> 	                       1000baseT/Full
> 	                       10000baseT/Full
> 	                       2500baseT/Full
> 	                       5000baseT/Full
> 	Port type: mdi
> 
> Port for eth1:
> 	Port id: 2
> 	Vacant: no
> 	Supported MII interfaces : 10gbase-r
> 	Port type: sfp
> 
> Port for eth1:
> 	Port id: 3
> 	Vacant: no
> 	Supported link modes:  10000baseCR/Full
> 	Port type: mdi
> 
> Note that here, we have 3 ports :
>  - The Copper port
>  - The SFP Cage itself, marked as 'occupied'
>  - The SFP module
> 
> This series builds on top of phy_port and phy_link_topology to allow
> tracking the ports of an interface. We maintain a list of supported
> linkmodes/interfaces on each port, which allows for fine-grained
> reporting of each port's capability.
> 
> What this series doesn't do :
>  - We don't support selecting which port is active. This is the next step.
>  - We only support PHY-driven combo ports. The end-goal of this whole
>    journey that started with phy_link_topology is to get support for MII
>    muxes, such as the one we have on the Turris Omnia. This will eventually
>    be upstreamed as well.
> 
> If you want to play around with it, here's [1] the patched ethtool that I've
> been using to produce the outputs above.
> 
> Thanks !
> 
> Maxime
> 
> [1] : https://github.com/minimaxwell/ethtool/tree/mc/ethtool_port

Some feedback from Andrew, Russell or Heiner would be very appreciated.

@Maxime: I went over sashiko feedback and I *think* it ranges from
orthogonal to wrong, but it would be useful if you could go over it.

Thanks,

Paolo