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Registered: ‎09-30-2011

Zynq u-Boot Support of Micrel KSZ9031

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We are booting  a custom board with a Micrel KSZ9031 transceiver using standard u-boot. We are able to get to the u-boot prompt, ethernet linked and seemed to receive packets but would not transmit. I checked the device tree and noticed that we were set for the default

 

compatible = "cdns,zynq-gem", "cdns,gem";

 

But if I override it with what it should be (which from the forum here, I have come to believe should be)

 

compatible = "micrel,ksz9031";

 

Then no ethernet device is identified at all. 

 

My u-boot config includes the necessary

CONFIG_PHY_MICREL=y

CONFIG_PHY_MICREL_KSZ90X1=y

 

So I am still missing something - probably in the device tree, my gut tells me.
Any ideas?

 

Thanks!

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1,239 Views
Registered: ‎09-30-2011

Well, the problem turned out to be signal integrity. The Micrel part was able to negotiate a link to 1G and even to receive packets at 1G but failed to transmit at 1G. When I throttled the system down to 100Mb it was all good. There you go.

 

I would note that on the version of u-boot (and Linux) that I was using specifying

compatible = "micrel,ksz9031";

was a mistake and the default 

compatible = "cdns,zynq-gem", "cdns,gem";

is what is needed to properly ID the PHY

View solution in original post

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Highlighted
1,240 Views
Registered: ‎09-30-2011

Well, the problem turned out to be signal integrity. The Micrel part was able to negotiate a link to 1G and even to receive packets at 1G but failed to transmit at 1G. When I throttled the system down to 100Mb it was all good. There you go.

 

I would note that on the version of u-boot (and Linux) that I was using specifying

compatible = "micrel,ksz9031";

was a mistake and the default 

compatible = "cdns,zynq-gem", "cdns,gem";

is what is needed to properly ID the PHY

View solution in original post