2021-08-11 18:24:58

by Andrew Lunn

[permalink] [raw]
Subject: Re: [PATCH v3 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x

> I hope that using "*-internal-delay-ps" for Mac would be the right option.
> Shall i include these changes as we discussed in next revision of the patch?

Yes, that seems sensible. But please limit them to the CPU port. Maybe
return -EINVAL for other ports.

Andrew


2021-08-11 20:15:59

by Russell King (Oracle)

[permalink] [raw]
Subject: Re: [PATCH v3 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x

On Wed, Aug 11, 2021 at 08:23:04PM +0200, Andrew Lunn wrote:
> > I hope that using "*-internal-delay-ps" for Mac would be the right option.
> > Shall i include these changes as we discussed in next revision of the patch?
>
> Yes, that seems sensible. But please limit them to the CPU port. Maybe
> return -EINVAL for other ports.

Hmm. Don't we want ports that are "MAC like" to behave "MAC like" ?
In other words, shouldn't a DSA port that can be connected to an
external PHY should accept the same properties as a conventional
Ethernet MAC e.g. in a SoC device?

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

2021-08-11 20:22:16

by Vladimir Oltean

[permalink] [raw]
Subject: Re: [PATCH v3 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x

On Wed, Aug 11, 2021 at 09:14:14PM +0100, Russell King (Oracle) wrote:
> On Wed, Aug 11, 2021 at 08:23:04PM +0200, Andrew Lunn wrote:
> > > I hope that using "*-internal-delay-ps" for Mac would be the right option.
> > > Shall i include these changes as we discussed in next revision of the patch?
> >
> > Yes, that seems sensible. But please limit them to the CPU port. Maybe
> > return -EINVAL for other ports.
>
> Hmm. Don't we want ports that are "MAC like" to behave "MAC like" ?
> In other words, shouldn't a DSA port that can be connected to an
> external PHY should accept the same properties as a conventional
> Ethernet MAC e.g. in a SoC device?

+1, I thought the whole purpose of the discussion was to stop singling
out the CPU port as being special in any way w.r.t. RGMII delays.

2021-08-11 20:24:53

by Andrew Lunn

[permalink] [raw]
Subject: Re: [PATCH v3 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x

On Wed, Aug 11, 2021 at 11:20:19PM +0300, Vladimir Oltean wrote:
> On Wed, Aug 11, 2021 at 09:14:14PM +0100, Russell King (Oracle) wrote:
> > On Wed, Aug 11, 2021 at 08:23:04PM +0200, Andrew Lunn wrote:
> > > > I hope that using "*-internal-delay-ps" for Mac would be the right option.
> > > > Shall i include these changes as we discussed in next revision of the patch?
> > >
> > > Yes, that seems sensible. But please limit them to the CPU port. Maybe
> > > return -EINVAL for other ports.
> >
> > Hmm. Don't we want ports that are "MAC like" to behave "MAC like" ?
> > In other words, shouldn't a DSA port that can be connected to an
> > external PHY should accept the same properties as a conventional
> > Ethernet MAC e.g. in a SoC device?
>
> +1, I thought the whole purpose of the discussion was to stop singling
> out the CPU port as being special in any way w.r.t. RGMII delays.

Yes, sorry.

What we don't want is it acting upon phy-mode.

Andrew