GMAC TX and RX Clock Delay

[nikson]

Hi,

I designed a custom board with A20 and RTL8211CL gigabit ethernet phy. The board boots, but GE doesn't work; the board successfully connects through Fast Ethernet. 

The well-known delay between the RX/TX clock and RGMII data lines has to be implemented. Could someone provide code example on how to implement a delay of 2 ns for both RX and TX clocks, so I can include it in my version of u-boot?

From the A20 datasheet cannot be concluded how the bits from  GMAC CLOCK REGISTER translate into time.

Regards, Nikola

[JohnS]

Try asking somewhere other than a manufacturer site

Maybe armbian or u-boot or linux-sunxi or ... well give it some thought.

John

[LubOlimex]

We switched away from RTL8211CL few years ago. It had bad support in Linux. We now use Micrel GbE controllers which have both good Linux support and industrial version.

Still back then we managed to get RTL8211CL working properly by a workaround - setting the GbE to master mode. Check the below links about the situation back then:

1. Our patch (refer to "RealTek RTL8211x"): https://github.com/OLIMEX/OLINUXINO/blob/master/SOFTWARE/A20/A20-build-3.4.103-release-7/a20-phy_1000_100-dram.patch

2. Issue discussed over our GitHub: https://github.com/OLIMEX/OLINUXINO/issues/31

3. Issue at u-boot maililists: https://lists.denx.de/pipermail/u-boot/2016-March/249251.html

IMPORANT! The issues described above doesn't apply for currently manufactured boards since we switched from Realtek's RTL8211CL to Micrel's KSZ9031. The GitHub patch linked above contains the modifications for KSZ9031.

[alexey]

...
IMPORANT! The issues described above doesn't apply for currently manufactured boards since we switched from Realtek's RTL8211CL to Micrel's KSZ9031. The GitHub patch linked above contains the modifications for KSZ9031.

Dear LubOlimex, do you have any information regarding Buildroot support for Micrel/Microchip based boards?