Hi Andrew,

On Wed, Feb 19, 2025 at 11:38:02PM +0100, Lukasz Majewski wrote:

quoted

Hi Andrew,
  

quoted

On Wed, Feb 19, 2025 at 12:49:36PM +0100, Lukasz Majewski wrote:  

quoted

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.... :-)
  

quoted

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.

quoted

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. 

quoted

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

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