Re: [PATCH net-next 07/15] net: dsa: mt7530: do not run mt7530_setup_port5() if port 5 is disabled

[Arınç ÜNAL]

On 10.01.2024 21:23, Vladimir Oltean wrote:
> On Wed, Jan 10, 2024 at 10:26:54AM +0300, Arınç ÜNAL wrote:
> > > Are there existing systems that use PHY muxing? The possible problem I
> > > see is breaking those boards which have a phy-handle on gmac5, if the
> > > mt7530 driver is no longer going to modify its HWTRAP register.
> >
> > Ah see, for PHY muxing, the driver actually wants the phy-handle to be put
> > on the SoC MAC, and the PHY to be defined on the SoC ethernet's MDIO bus.
> > We don't even define gmac5 as a port on the switch dt-bindings.
>
> I noticed that from the code already. Maybe I shouldn't have said
> "gmac5" when I meant "the GMAC attached to switch port 5, aka GMAC0".
> I was under the impression that you were also using this slightly
> incorrect terminology, to keep a numerical association between the CPU
> port number and its directly attached GMAC.
>
> > While none of the DTs on the Linux repository utilise this, some of the
> > mt7621 DTs on OpenWrt do. The change in behaviour will only be that phy0/4
> > will be inaccessible from the SoC MAC's network interface. I de-facto
> > maintain the mt7621 device tree source files there. I intend to revert it
> > along with adding port 5 as a CPU port so that the conduit changing feature
> > becomes available.
>
> If OpenWrt kernels are always shipped in tandem with updated device
> trees (i.e. no Arm SystemReady IR platforms, where the DT is provided by
> U-Boot), I won't oppose to retracting features described via DT if their
> platform maintainers agree in a wide enough circle that the breakage is
> manageable.

I will see to this when the time comes.

> BTW, besides OpenWrt, what other software is deployed on these SoCs
> typically?

Other than OpenWrt which is widely used for these SoCs for its ease of
flashing and upgrading, compatibility with legacy U-boot versions that
usually come with any vendor making a product out of these SoCs, I can only
talk about what I deploy to run Linux. I use mainline U-Boot along with the
device trees from the Linux repository to boot mainline Linux kernels with
Buildroot as the filesystem.

Arınç