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

[Uwe Kleine-König]

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.
(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?

Best regards
Uwe
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