NuttX + LiteEth: Potential regression when using Hybrid Etherbone/Ethernet.

[enjoy-digital]

Reported by @AndrewD, to look at this:

• Run NuttX with LiteEth on a board with add_ethernet.
• Run NuttX with LiteEth on a board with add_etherbone + hybrid mode.
• If issue with the latter, fix.

Note that it's possible the issue with NuttX can also be reproduced with Linux if easier to test.

[AndrewD]

This is the way we integrated Hybrid Etherbone/Ethernet for testing on Arty:

        # Ethernet and/or Etherbone ---------------------------------------------------------------------
        if ethernet or etherbone:
            self.ethphy = LiteEthPHYMII(
                clock_pads = self.platform.request("eth_clocks"),
                pads       = self.platform.request("eth"))
            # Etherbone with optional Ethernet
            if etherbone:
                self.add_etherbone(
                    phy=self.ethphy,
                    ip_address=etherbone_ip,
                    with_ethmac=ethernet,
                )
            # Ethernet only
            elif ethernet:
                self.add_ethernet(phy=self.ethphy)

[enjoy-digital]

Thanks @AndrewD, @trabucayre has been able to reproduce the issue (even with LiteX netboot). This is related to the integration improvements. We just need to do a few iterations to find the root cause and we'll fix it.

[trabucayre]

Hi @AndrewD . I have fixed a small issue in add_etherbone method (https://github.com/enjoy-digital/litex/commit/13c57e8304d8c685268be67400a66a5f7c08c4a2). But you have to provides a mac_address parameter different than default value to avoid conflict with ethernet part.

Tested on arty with nuttx (master branch).

[AndrewD]

Excellent, I'll integrate this tomorrow.

I'd experimented with a separate mac address without success, however the clocking fix looks like the missing piece.

[enjoy-digital]

Hi @AndrewD,

we are going to add parameters to specify the different IP/MAC addresses and also add some check to ensure there are no collisions between Etherbone and Ethernet. @trabucayre will do the changes this morning and provide an update.

[trabucayre]

Hi,

See this PR. With these modifications is possible to pass all configurations (etherbone IP/MAC + ethernet local/remote IP and MAC).

[AndrewD]

Thanks @trabucayre and @enjoy-digital, I've confirmed this is now working nicely with bios and nuttx.

[enjoy-digital]

Good, thanks @AndrewD for the feedback.