Re: [PATCH v2 3/5] dt-bindings: net: Add HPE GXP UMAC

From: Hawkins, Nick
Date: Wed Aug 16 2023 - 12:27:38 EST


Hi Conor,

Thanks for your feedback. I will provide an explanation below.

> > +description:
> > + HPE GXP 802.3 10/100/1000T Ethernet Unifed MAC controller.
> > + Device node of the controller has following properties.
> > +
> > +properties:
> > + compatible:
> > + const: hpe,gxp-umac
> > +


> > + use-ncsi:
> > + type: boolean
> > + description:
> > + Indicates if the device should use NCSI (Network Controlled
> > + Sideband Interface).


> How is one supposed to know if the device should use NCSI? If the
> property is present does that mean that the mac hardware supports
> it? Or is it determined by what board this mac is on?
> Or is this software configuration?

Hi Conor,

There are two MAC's available in the ASIC but only one can support
NCSI. Even though it supports NCSI does not mean the board has
been physically wired to support it. In terms of the device tree I would
expect the "use-ncsi" to be present in the dts board specific file.

There will be hardware configurations where both MAC0 and MAC1
will be using the SERDES connections. In that case there will be no
NCSI available.

Is a better description needed here to explain this?

Thanks,

-Nick Hawkins