cve2/lint
Pirmin Vogel 9738b6c703 [rtl] Rework core_busy signals, remove feedback to clk
This commit reworks the generation of the `core_busy` signal used to
control the main clock gate of the core. Without this commit, the
controller generates a separate `first_fetch` signal only asserted in
the FIRST_FETCH state that directly controls `core_busy` and thus the
main clock gate. This is problematic as it introduces a feedback to
from the controller state into the clock.

This commit removes the problematic signal and changes the generation of
`ctrl_busy` in the FIRST_FETCH state of the controller. This signal is
now used to control the main clock gate in all states (previously all
except FIRST_FETCH) but it gets registered, thus it does not introduce
the feedback into the clock.

This resolves lowRISC/ibex#211.

Signed-off-by: Pirmin Vogel <vogelpi@lowrisc.org>
2019-11-14 12:55:16 +01:00
..
verilator_waiver.vlt [rtl] Rework core_busy signals, remove feedback to clk 2019-11-14 12:55:16 +01:00