[dv] Add spurious responses to memory agent #2185
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I still need to do a full regression with this version but regressions with earlier prototypes were working. |
dv/uvm/core_ibex/common/ibex_mem_intf_agent/ibex_mem_intf_monitor.sv
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dv/uvm/core_ibex/common/ibex_mem_intf_agent/ibex_mem_intf_monitor.sv
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| while(!(vif.monitor_cb.request && vif.monitor_cb.grant)) begin | ||
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| if (vif.monitor_cb.rvalid && !vif.monitor_cb.spurious_response) begin |
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The !spurious_response bit seems slightly surprising here. Should the monitor really care about whether the response was the one we were waiting for? I guess the problem is the outstanding_accesses counter, but maybe that really belongs in the driver or the sequence rather than the monitor, since those components know whether they have anything "in flight".
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This is partially down to laziness on my part but pre this change spurious responses didn't exist and downstream users of the monitor (i.e. those things connecting to the item_collected_port) were expecting everything they receive to represent an actual transaction that occurred (in particular the co-sim scoreboard). If we output spurious responses here we'll need all downstream users of the monitor to filter out spurious responses. This felt like a cleaner design.
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Ok, that feels reasonable. Maybe an example of where "the principled solution" is also the wrong one :-)
dv/uvm/core_ibex/common/ibex_mem_intf_agent/ibex_mem_intf_response_seq_lib.sv
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GregAC
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A spurious response is one that isn't associated with any on-going request. With this new feature the memory agent can generate them randomly when the interface is idle (i.e. there are no outstanding requests).
GregAC
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A spurious response is one that isn't associated with any on-going request. With this new feature the memory agent can generate them randomly when the interface is idle (i.e. there are no outstanding requests).