DP83869HM: Is RGMII-SGMII bridge mode of operation supported by DP83869HMRGZT in inux?

Hi, 

Our PHY supports RGMII to SGMII bridge mode and the linux driver can support this. 

Best,
J

Thank you. Can you point me to the driver code/repo? Also, is there an EVM with an SDK we can try this ?

Hi,

Driver is available at this link: https://www.ti.com/tool/ETHERNET-SW

you should be able to replicate this with DP83868EVM but you will need to connect the EVM to RGMII MAC. For SGMII, you can either connect to another EVM which can change to a copper connection or connect SGMII to SGMII MAC.

Best,

J

Thank you !
Here is the test setup I am envisioning to test the bridge mode along with our board as a proof of concept. Both involve two EVMs
Setup 1:
   Our board MAC1  --<rgmii>--  [DP83868EVM-1] -----------<SGMII> ---------[DP83868EVM-2] ---<rgmii>---[MAC2 of our board]
                              -- <MDIO> -                                                                                       -- <MDIO> -


In this setup, we are planning to pan out the RGMII pins out to our board's two MACs.  Also we are draw the MDC/MDIO out of EVM to connect our Board's MDIO bus.
The idea is that we can boot our board's linux and configure the PHY using the linux driver and try to communicate between the two ethernet interfaces.
Will this be feasible? Or will the EVM's microcontroller try to control the PHY's instead of our board's MAC ? Is there a way to disable that?

Setup 2:
   Our board MAC1  --<rgmii>--  [DP83868EVM-1] -----------<SGMII> ---------[DP83868EVM-2] ---<RJ45>---[A test PC]
                              -- <MDIO> -                                                                                           

Similiar to setup 1, but only one MAC of ours is in use. We would like to control the PHY on one of the EVM-1 using our MAC/MDIO  and let the other EVM be in a SGMII-RJ45 bridge . We can then ping/iperf between the Test PC and our board.

Is it achievable? As in setup-1, can the micro controller be allowed to be in a stand-by, not interfering with the PHY on EVM-1?

Regards

Mahesh

Hi Mahesh, 

For both setups, microcontroller inside the EVM will not interact with the PHY unless you use USB2MDIO software so there shouldn't be any issue hooking up MDIO to your board's linux and configure the PHY using the linux driver. 

Best,
J

Thanks for the support so far. 

I know it was acknowledged it before, but just confirming again before we commit to adopting this DP83869HM in to our solution, the RGMII(local mac)-SGMII  (remote) bridge functionality is supported in hardware and software correct?
Since we will be operating it in high temperatures (~85 degrees), will this operate without errors? 
Has this chip been tested at high temperatures in this mode at TI?
If so, will you be able to provide details of the testing done at TI in this bridge mode? If possible, any test cases/configuration you can share, that will be very helpful.

Regarding the prototype testing,

I might go with the test setup 2 as below:
Setup 2:
   Our board MAC1  --<rgmii>--  [DP83869EVM-1] -----------<SGMII> ---------[DP83869EVM-2] ---<RJ45>---[A test PC]
                              -- <MDIO> -    

I am assuming the PHY in DP83869EVM-1 here can be put in the RGMII to SGMII bridge through linux device tree file. (Pls confirm)
My plan is to draw the RGMII & MDIO lines out of our board to the EVM-1's PHY and power the EVM-1 using the USB. If done correctly, I hope that works (Pls confirm)

No re-work needed in the DP83869EVM-2  in the above setup. The PHY in the  DP83869EVM-2 can be put in  SGMII to RJ45 mode using the USB2MDIO software ? (Pls confirm)

Hope this setup works.

Thanks in advance,

Hi Mahesh, 

Mahesh Radhakrishnan said:

I know it was acknowledged it before, but just confirming again before we commit to adopting this DP83869HM in to our solution, the RGMII(local mac)-SGMII  (remote) bridge functionality is supported in hardware and software correct?
Since we will be operating it in high temperatures (~85 degrees), will this operate without errors? 
Has this chip been tested at high temperatures in this mode at TI?
If so, will you be able to provide details of the testing done at TI in this bridge mode? If possible, any test cases/configuration you can share, that will be very helpful.

The device was tested in the temperature range mentioned in the datasheet. 

Mahesh Radhakrishnan said:

I am assuming the PHY in DP83869EVM-1 here can be put in the RGMII to SGMII bridge through linux device tree file. (Pls confirm)

Yes, this can be put in linux device tree file. 

Mahesh Radhakrishnan said:

My plan is to draw the RGMII & MDIO lines out of our board to the EVM-1's PHY and power the EVM-1 using the USB. If done correctly, I hope that works (Pls confirm)

This should work as long as the MSP430 in the EVM is not used to access the registers. Please ensure the EVM and the board is common grounded. 

Mahesh Radhakrishnan said:

No re-work needed in the DP83869EVM-2  in the above setup. The PHY in the  DP83869EVM-2 can be put in  SGMII to RJ45 mode using the USB2MDIO software ? (Pls confirm)

You will need to solder the capacitors and the SMA connector to connect SGMII lines to the EVM. 
Follow this to set the EVM into SGMII to copper mode:


Best,
J

J said:

This should work as long as the MSP430 in the EVM is not used to access the registers. Please ensure the EVM and the board is common grounded. 

If I connect the USB to the EVM, but NOT launch the USB2MDIO software, will the MSP430 try to access the PHY registers? (something I don't want it to happen)

Hi Mahesh, 

No, MSP430 will not access the PHY register unless you use USB2MDIO software so there is no need to worry about that.

Best,

J