How are the MDIO busses routed out on the T1040RDB?

[Larry5335]

Can you help me understand the layout of the MDIO buses on the T1040RDB?  In particular, Section 5.4.2.1 of T1040DPAARM lists MDIO-1, MDIO-2, MDIO-3, MDIO-4, MDIO-5 and 2 dedicated MDIOs for FMANv3. I’ve found that that first dedicated MDIO (at 0xFE4F_C000) is used for the Realtek Phy for ETH0, ETH1 and ETH2.  Are the other MDIOs connected to anything?

The reason I ask is that I can’t receive data.  I followed U-boot through and noticed it’s initializing something on MDIO-3 (at 0xFE4E_5000).  Once that is initialized, I’m able to receive data. However, I don’t know what device is on that bus and can’t figure out why U-boot is initializing it.

[lunminliang · Accepted solution]

Hello Larry Stein,

Which ETH connector on the board do you use? On J19, they're Realtek PHYs with ADDR 0x04 and 0x05. On J20, it's SGMII PHY with ADDR 0x01.

If you "followed U-boot through and noticed it’s initializing something on MDIO-3 (at 0xFE4E_5000)", I think you can further check what MDIO_CTL[PORT_ADDR/PHY_ADDR] it initiailized at 0xFE4E_5034, to tell which PHY it addressed. On the T1040RDB board, RGMII, SGMII, and QSGMII PHYs used the same ehternet management interface, with different PHY ADDRs.

Have a great day,
Lunmin

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