[RESEND PATCH] ARM: dts: socfpga: Add basic support for Terrasic's de10-nano

[Andrew Lunn]

On Wed, Jan 29, 2025 at 09:35:21AM +0100, Uwe Kleine-König wrote:
> Hello Andrew,
> 
> On Tue, Jan 28, 2025 at 06:44:26PM +0100, Andrew Lunn wrote:
> > > +&gmac1 {
> > > +	/* Uses a KSZ9031RNX phy */
> > > +	status = "okay";
> > > +	phy-mode = "rgmii";
> > > +
> > > +	rxd0-skew-ps = <420>;
> > > +	rxd1-skew-ps = <420>;
> > > +	rxd2-skew-ps = <420>;
> > > +	rxd3-skew-ps = <420>;
> > > +	txen-skew-ps = <0>;
> > > +	txc-skew-ps = <1860>;
> > > +	rxdv-skew-ps = <420>;
> > > +	rxc-skew-ps = <1680>;
> > > +};
> > 
> > The convectional meaning of phy-mode 'rgmii' is that the PCB provides
> > the 2ns delay. Here you are abusing the
> > 
> > > +	txc-skew-ps = <1860>;
> > > +	rxc-skew-ps = <1680>;
> > 
> > To add these delays.
> 
> Ah, at some point I already knew that. Thanks for repeating that hint.

No problem a with the hint. This is a nice easy case. Some vendors
have made a big mess with RGMII delays, hiding it in the bootloader,
and giving customers bad advice. That is much harder to fix.

> (Back then it was for
> arch/arm64/boot/dts/rockchip/rk3568-qnap-ts433.dts.)
> 
> > Please test without these two lines, and change phy-mode to
> > 'rgmii-id'. 1680 is rather low, so it might not work. Look for CRC
> > errors for received packets.
> 
> I did an apt upgrade involving > 100 MB downloads with rgmii-id and
> afterwards I had:
> 
> 	# ip -stats link show dev eth0
> 	2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAU
> 	LT group default qlen 1000
> 	    link/ether ee:5f:09:22:72:da brd ff:ff:ff:ff:ff:ff
> 	    RX:  bytes packets errors dropped  missed   mcast
> 	     158336739  113000      0       0       0       0
> 	    TX:  bytes packets errors dropped carrier collsns
> 		482481    5094      0       0       0       0
> 
> so that seems to be fine, right?

Yes, this looks good.

Thanks
	Andrew