openXC7 - slave_oserdese has disconnected OQ/OFB output ports

[kerimbavcic]

NOTE: when using Vivado, the issue is not present!

When using openXC7 (place and route step) we get an error in OSERDESE2 module, slave_oserdese to be specific, where it says OQ and OFB ports are not connected. The exact message we get is:

ERROR: OSERDESE2 'u_hdmi_top.u_hdmi_backend._tdms_sdat[0].u_oser_dat.slave_oserdese' has disconnected OQ/OFB output ports
2 warnings, 1 error
make: *** [Makefile:53: top.fasm] Error 25

Here is the code snippet:

openXC7 installed version (https://github.com/openXC7/toolchain-installer):

• commit hash - 53b1286
• yosys version - 0.38
• nextpnr version - 0.8.2

We noticed that openXC7 had some issues with OSERDESE2 before in the past which were fixed as part of this bugfix.

[chili-chips-ba]

• @hansfbaier, @MikeReznikov for comment

[hansfbaier]

@chili-chips-ba Can I have a test design, that highlights your issue?

[chili-chips-ba]

... RTL is already checked in. @kerimbavcic and @harunkovacevic are in the process of checking in the openXC7 part of the setup:

• https://github.com/chili-chips-ba/openeye-CamSI/tree/main/3.build/openXC7

They'll ping you shortly...

[harunkovacevic]

@hansfbaier You can find all necessary files here:

• https://github.com/chili-chips-ba/openeye-CamSI/tree/main/3.build/openXC7

[AdamLee7]

i have fix this error, I'll submit the code in a moment

[AdamLee7]

https://github.com/openXC7/nextpnr-xilinx/pull/53 I fixed the bug in the pack code, but due to other missing logic in packing and routing, and incomplete prjxray-db information, your netlist may still not work properly.

[chili-chips-ba]

@AdamLee7 what is your recommendation for our next step?

• Is it to simply pull in and try your patch
• then keep reporting issues as we come across them?!

[hansfbaier]

@chili-chips-ba If your tests succeeds I will merge. The patch looks good to me so far.

[AdamLee7]

@AdamLee7 what is your recommendation for our next step?

• Is it to simply pull in and try your patch
• then keep reporting issues as we come across them?!

yes, just do it, if there is any problem, you can commit an issue

[harunkovacevic]

We have cloned nextpnr-xilinx repo, adapted _xilinx/pack_ioxc7.cc file, compiled and installed a new nextpnr version. Then we ran a build and "disconnected ports OSERDESE2 issue" was fixed but we've gotten a new error explained in this issue.