[PATCH] arm: clk: Add ETH switch clock description for vf610 SoC
Lukasz Majewski
lukma at denx.de
Thu Feb 20 06:48:26 PST 2025
Hi Andrew,
> On Wed, Feb 19, 2025 at 11:38:02PM +0100, Lukasz Majewski wrote:
> > Hi Andrew,
> >
> > > On Wed, Feb 19, 2025 at 12:49:36PM +0100, Lukasz Majewski wrote:
> > > > The NXP's vf610 soc is equipped with L2 switch IP block from
> > > > More Than IP (MTIP) vendor.
> > > >
> > > > It requires special clock (VF610_CLK_ESW) to be operational.
> > >
> > > So you have a driver for this switch? It has been talked about in
> > > the past, but nobody made any progress with it. Ah, it was you in
> > > 2020.
> >
> > Yes, I'm going to try another time to upstream it.... :-)
> >
> > > It
> > > will be interesting to see what you came up with in the end, pure
> > > switchdev or a DSA driver.
> >
> > I think it would be:
> >
> > 1. Standalone driver, which would configure the L2 switch from the
> > very beginning to work (this is different from FEC on imx28/vf610
> > where switch is bypassed)
> >
> > 2. It will use the in-switch registers to have two network
> > interfaces separated. As a result - it may be slower than the
> > fec_main.c in this use case.
>
> Seems like a reasonable compromise. You would only load this driver if
> you intend to make use of the switch...
Yes, the main use case would be the switch (after bridge ... command
called).
However, until then we shall? have port separation.
>
> > 3. When somebody call "bridge ..." on it - then the in-switch
> > separation would be disabled. This is the "normal" state of
> > operation for L2 switch, which would be a HW accelerator for
> > bridging.
> >
> > 4. The switchdev would be used to manage it
> >
> > 5. This would be just a very simple driver - just bridging and
> > startup of the L2 switch.
> >
> > After we would have a consensus (i.e. it would be pulled to
> > mainline) - I would proceed further.
> >
> > I will try to not touch fec_main.c driver - just write standalone,
> > new for MoreThanIP L2 switch driver.
>
> It might make sense to refactor the MDIO code into a helper which both
> can share? No point duplicating that.
This is a latter step (common MDIO library code), IMHO.
>
> > If somebody would like to use FEC, then he will insert the proper
> > module. If switch, another one can be inserted, depending o the
> > target use case.
>
> This all seems like a reasonable way forward.
+1
>
> MoreThanIP is now part of Synopsys. I wounder if this IP now exists in
> other SoCs? The press release however suggests Synopsys was
> interesting in the high speed interfaces, not a two ports Fast
> Ethernet switch.
I would need some detailed documentation....
>
> Andrew
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma at denx.de
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