[WireDFT] Add support for wiring optional clock div bypass signal. #5219

dtzSiFive · 2023-05-17T15:24:21Z

If a signal is annotated as the clock divider bypass signal, wire it to clock gates that have the expected port.

Like test_en wiring the port number is hardcoded, but unlike test_en this ignores the "bypass" port if that port doesn't match the expected bypass port name/dir/type.

Warning is emitted if looks compatible but name doesn't match and bypass signal annotation is found.

lib/Dialect/FIRRTL/Transforms/WireDFT.cpp

seldridge

Nice.

It would be nice if the enable and bypass could be wired in one shot. However, that is a larger refactor. Future work? (I'd rather just remove this pass and replace it with a Chisel-side solution, though.)

lib/Dialect/FIRRTL/Transforms/WireDFT.cpp

Per reviewer feedback (and suggested code), thanks!! Note this tweaks the insertion point for the indexing to be as early as possible after the value is defined, to ensure its available (dominates) as much as needed.

lib/Dialect/FIRRTL/Transforms/WireDFT.cpp

youngar

🥇

…5219) If a signal is annotated as the clock divider bypass signal, wire it to clock gates that have the expected port. Like test_en wiring the port number is hardcoded, but unlike test_en this ignores the "bypass" port if that port doesn't match the expected bypass port name/dir/type. Warning is emitted if looks compatible but name doesn't match and bypass signal annotation is found.

…5219) (#5225) If a signal is annotated as the clock divider bypass signal, wire it to clock gates that have the expected port. Like test_en wiring the port number is hardcoded, but unlike test_en this ignores the "bypass" port if that port doesn't match the expected bypass port name/dir/type. Warning is emitted if looks compatible but name doesn't match and bypass signal annotation is found.

dtzSiFive added 3 commits May 17, 2023 10:01

[WireDFT] Add support for wiring optional clock div bypass signal.

11a2631

[WireDFT] Add test showing behavior w/unexpected bypass port.

81abb75

[WireDFT] warn if not wiring bypass port only because of its name.

b9d5733

dtzSiFive requested review from seldridge and youngar May 17, 2023 15:24

youngar reviewed May 17, 2023

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