Re: [PATCH 2/2] net: stmmac: Add Ingenic SoCs MAC support.

From: Andrew Lunn
Date: Tue Jun 08 2021 - 10:05:20 EST


On Tue, Jun 08, 2021 at 09:48:38PM +0800, Zhou Yanjie wrote:
> Hello Andrew,
>
> On 2021/6/8 下午8:21, Andrew Lunn wrote:
> > Please wrap your text to around 75 characters per line.
>
>
> Sure.
>
>
> >
> > I suspect you don't understand RGMII delays. As i said, normally, the
> > MAC does not add delays, the PHY does. Please take a closer look at
> > this.
>
>
> According to the description of ethernet-controller.yaml, "rgmii" seems
>
> to allow MAC to add TX delay (the description in ethernet-controller.yaml
>
> is "RX and TX delays are added by the MAC when required"), while rgmii-id
>
> and rgmii-txid do not allow MAC to add delay (the description in
>
> ethernet-controller.yaml is"RGMII with internal RX and TX delays provided
>
> by the PHY, the MAC should not add the RX or TX delays in this case" and
>
> "RGMII with internal TX delay provided by the PHY, the MAC should not add
>
> an TX delay in this case"), I will add support for the other three RGMII
> modes
>
> in the next version (I forgot to reply to this in the previous email).

Please follow the code all the way through. What gets passed to
phylink_create() is very important. If you have both the MAC and the
PHY adding delays, bad things will happen.

Andrew