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rocket: Fix UB due to optimised away DFFs 

As both clock and async reset for the debug DFFs were 0, and there was
no initial value on them, they were being validly optimised away by
newer Yosys versions to 1'bx which was propagating into and breaking the
core.

This fixes the problem by tying the async resets to the CPU reset
signal.

Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2020-11-28 11:15:42 +00:00
parent 52a1622895
commit 61895bef37
1 changed files with 2 additions and 2 deletions
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4
litex/soc/cores/cpu/rocket/core.py
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@ -123,7 +123,7 @@ class RocketRV64(CPU):
# debug (ignored) # debug (ignored)
#i_resetctrl_hartIsInReset_0 = 0, #i_resetctrl_hartIsInReset_0 = 0,
i_debug_clock = 0, i_debug_clock = 0,
i_debug_reset = 0, i_debug_reset = ResetSignal() | self.reset,
#o_debug_clockeddmi_dmi_req_ready = , #o_debug_clockeddmi_dmi_req_ready = ,
i_debug_clockeddmi_dmi_req_valid = 0, i_debug_clockeddmi_dmi_req_valid = 0,
i_debug_clockeddmi_dmi_req_bits_addr = 0, i_debug_clockeddmi_dmi_req_bits_addr = 0,
@ -134,7 +134,7 @@ class RocketRV64(CPU):
#o_debug_clockeddmi_dmi_resp_bits_data = , #o_debug_clockeddmi_dmi_resp_bits_data = ,
#o_debug_clockeddmi_dmi_resp_bits_resp = , #o_debug_clockeddmi_dmi_resp_bits_resp = ,
i_debug_clockeddmi_dmiClock = 0, i_debug_clockeddmi_dmiClock = 0,
i_debug_clockeddmi_dmiReset = 0, i_debug_clockeddmi_dmiReset = ResetSignal() | self.reset,
#o_debug_ndreset = , #o_debug_ndreset = ,
#o_debug_dmactive = , #o_debug_dmactive = ,
i_debug_dmactiveAck = 0, i_debug_dmactiveAck = 0,