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pcs: rx: Only flush on state change 

The PCS state machine is evaluated every cycle, but its outputs are only
registers when the rx_bits module indicates. However, the flush signal
is not registered and is instead combinatorial. Although it's OK to
evaluate the other outputs every cycle, we should only indicate if we
are actually going to change state.

Fixes: d351291 ("Initial commit")
Signed-off-by: Sean Anderson <seanga2@gmail.com>
This commit is contained in:
Sean Anderson 2022-08-06 22:08:09 -04:00
parent f8bb110caa
commit 03715d4a83
1 changed files with 10 additions and 4 deletions
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12
rtl/pcs.v
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@ -395,9 +395,9 @@ module pcs_rx_bits (
end
/*
* If we are flushing flush then activity is based on stale
* data. Ignore it so we don't accidentally detect activity for
* data we are going to flush anyway.
* If we are flushing then activity is based on stale data.
* Ignore it so we don't accidentally detect activity for data
* we are going to flush anyway.
*/
if (flush)
activity_next = 0;
@ -491,6 +491,11 @@ module pcs_rx (
endcase
start = 0;
/*
* XXX: flush (unlike everything else here) is combinatorial;
* we should only flush if we are actually evaluating the
* state.
*/
flush = 0;
rx_next = rx;
ce_next = indicate;
@ -560,6 +565,7 @@ end
;
`CODE_T:
if (aligned[4:0] == `CODE_R) begin
if (indicate)
flush = 1;
state_next = IDLE;
valid_next = 0;