Error IR Drop in caravel_user_project with an OpenFPGA

[CristopherA96]

Hi,

Description

I have the next issue when running user_project_wrapper process.

I have on each instance of the fpga_top the declaration of vccd1 and vssd1, I consider that connections will be done with the user_project_wrapper, but it is still showing me those errors.

How can I treat those errors?

[STEP 23]
[INFO]: Creating IR Drop Report (log: ../my_path/caravel_user_project/openlane/user_project_wrapper/runs/23_06_22_14_31/logs/signoff/23-irdrop.log)...
[ERROR]: during executing openroad script /openlane/scripts/openroad/irdrop.tcl
[ERROR]: Log: ../my_path/caravel_user_project/openlane/user_project_wrapper/runs/23_06_22_14_31/logs/signoff/23-irdrop.log
[ERROR]: Last 10 lines:
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1582.520um, 2417.880um), layer: 5.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1582.520um, 2417.880um), layer: 6.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1582.520um, 2342.880um), layer: 5.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1582.520um, 2342.880um), layer: 6.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1582.520um, 2267.880um), layer: 5.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1582.520um, 2267.880um), layer: 6.
[WARNING PSM-0038] message limit reached, this message will no longer print
[ERROR PSM-0078] IR drop setup failed.  Analysis can't proceed.
Error: irdrop.tcl, 37 PSM-0078
child process exited abnormally

[ERROR]: Creating issue reproducible...

Issue reproducible This is the generated issue file.

issue_reproducible.zip

Setup

Linux Mint RAM 32GB

Working with the latest version of caravel_user_project.

[maliberty]

That message usually indicates some problem in the pdn generation. Could you show a screen shot around the referenced area? @gadfort for thoughts

[vijayank88]

@CristopherA96 In discussion #1862 itself i requested pdn stage test case. Steps to create test case: https://openlane.readthedocs.io/en/latest/for_developers/using_or_issue.html#manually

[kareefardi]

@CristopherA96 In discussion #1862 itself i requested pdn stage test case. Steps to create test case: https://openlane.readthedocs.io/en/latest/for_developers/using_or_issue.html#manually

Or use CREATE_REPRODUCIBLE_FROM_SCRIPT too

[CristopherA96]

How can I add that variable if I am working into caravel user project repository, and as I know it is not a flow variable that can be set into config.json, and doing manually requires to be inside openlane container.

Thanks

[kareefardi]

How can I add that variable if I am working into caravel user project repository, and as I know it is not a flow variable that can be set into config.json, and doing manually requires to be inside openlane container.

Thanks

If you are using caravel user project Makefile, you should make a temporary edit here: https://github.com/efabless/caravel_user_project/blob/3a71fab0255a5eea4311f453e6ea95e7f16a992e/openlane/Makefile#L25. Replace flow.tcl with CREATE_REPRODUCIBLE_FROM_SCRIPT=openroad/pdn.tcl flow.tcl

[CristopherA96]

This is the new issue, by following the instructons that you told me.

issue_reproducible.zip

[maliberty]

@gadfort this looks to be a pdn issue if you have time to take a look.

[gadfort]

@maliberty There is a missing:

add_pdn_connect -grid stdcell_grid -layers "met4 met5"

[vijayank88]

@gadfort Can you please enable export FP_PDN_CHECK_NODES='1'; in run.sh and run the flow? Log

[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1862.520um, 1095.880um), layer: 5.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1862.520um, 1095.880um), layer: 6.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1862.520um, 1067.880um), layer: 5.
[WARNING PSM-0038] Unconnected PDN node on net vccd1 at location (1862.520um, 1067.880um), layer: 6.
[WARNING PSM-0038] message limit reached, this message will no longer print
[ERROR PSM-0069] Check connectivity failed.
Error: pdn.tcl, 39 PSM-0069

Where to define add_pdn_connect again?

[gadfort]

It should be added: https://github.com/The-OpenROAD-Project/OpenLane/blob/3bc9d02d0b34ad032921553e512fbe4bebf1d833/scripts/openroad/common/pdn_cfg.tcl#L126

Without it there are no vias added to the macro

[vijayank88]

@CristopherA96 Please share your carvel repo link with design files. Are you using latest OpenLane commit?

[PaulinaRicoG]

Hi @vijayank88, I am Cristopher's partner.

Here is the link of the repository.

OL_OFPGA_repo

[maliberty]

@gadfort this sounds like a pdn issue

[kareefardi]

FP_PDN_ENABLE_RAILS was disabled causing problems.