[obi_cut]: Fixed sbr_port_rsp_o.gnt stuck at 1

[luca24balboni]

Fixed sbr_port_rsp_o.gnt of obi_cut module directly connected to ready_o port of spill_register causing protocol violation.

[micprog]

Checking the spec, this is legal behavior:

[alenad95]

Hi @micprog, thanks for the feedback! I'm adding myself to the discussion since I'm supervising @luca24balboni.

I would have expected the actual grant being propagated through the CUT. Since the behavior of the grant coming from the CUT is compliant to the OBI protocol, I'm closing the PR.

[micprog]

Since the goal of the cut module is to cut combinational paths, especially the handshake signals should not be propagated straight through. If you want the behavior in this PR added, it might make sense to add it in case the CombGnt bit in the ObiCfg is set, although this configuration does not enforce this behavior, only permits it (the configuration is discouraged for performance reasons).