On Wed, Mar 17, 2021 at 10:30 AM Alexander Dahl <ada@thorsis.com> wrote:
Hello,

for testing some new mikroBUS modules I got a dusty SAMA5D2-SOM1-EK1 from our
shelf and build recent DistroKit master for it. Nice thing: SD card works in
both ports. However ethernet does not work correctly out of the box. :-/

In barebox shell it uses a random mac address (the real one is in a small
eeprom on the SoM), dhcp and ping successful.

In Linux (5.11.4) however it also uses a random mac address and furthermore
either the micrel ethernet phy is not found at all or the link can not be set
to up. Tried both nmtui and raw iproute2 command.

Hey Alexander,

I don't know if this will apply to you with sama5d2-som1-ek1, but we have a board that is based on sama5d2-som1 that has ksz8081rna phy, which based on the strap on options configured via pull up/down is on phy 4.
We are in the process of updating from linux-4.14 to linux-5.4. A problem that was noticed on update to linux-5.4 was that the Ethernet port stopped working after power on boot, but would work after a subsequent soft reboot.
I noticed that the phy address used in arch/arm/boot/dts/at91-sama5d27_som1.dtsi didn't match the one for our board in either the linux-4.14 or linux-5.4 tree, but we never noticed a problem when we did initial bring up of our board with linux-4.14 a couple years ago. When I fixed the device tree to use the correct phy address 4 for our board. The problem went away and the Ethernet port now works properly on linux-5.4.

-Jon