[otbn,rtl] Shuffle timing of some internal signals
The point of this is to allow us to flop the idle_o signal (through a
prim_mubi4_sender) and the intr_done_o signal (by adding a flop to the
prim_intr_hw instance).
It turns out that we can do this without changing the external timing
at all. The following signals move forward a cycle:
locked (now called locking)
otbn_dmem_scramble_key_req_busy
otbn_imem_scramble_key_req_busy
idle
done
and we rename the is_not_running signals to have an explicit _d and
_q. Note that these don't quite line up with the is_not_running and
is_not_running_r that we had before: is_not_running_q is the same
timing as is_not_running.
Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/hw/ip/otbn/rtl/otbn_controller.sv b/hw/ip/otbn/rtl/otbn_controller.sv
index 8389ce2..a3cf232 100644
--- a/hw/ip/otbn/rtl/otbn_controller.sv
+++ b/hw/ip/otbn/rtl/otbn_controller.sv
@@ -21,8 +21,8 @@
input logic clk_i,
input logic rst_ni,
- input logic start_i, // start the processing at address zero
- output logic locked_o, // OTBN in locked state and must be reset to perform any further actions
+ input logic start_i, // start the processing at address zero
+ output logic locking_o, // Controller is in or is entering the locked state
input prim_mubi_pkg::mubi4_t escalate_en_i,
output controller_err_bits_t err_bits_o,
@@ -308,7 +308,7 @@
assign executing = (state_q == OtbnStateRun) ||
(state_q == OtbnStateStall);
- assign locked_o = (state_q == OtbnStateLocked) & ~secure_wipe_running_i;
+ assign locking_o = (state_d == OtbnStateLocked) & ~secure_wipe_running_i;
assign start_secure_wipe_o = executing & (done_complete | err) & ~secure_wipe_running_i;
assign jump_or_branch = (insn_valid_i &
@@ -499,7 +499,7 @@
if (!rst_ni) begin
err_bits_q <= '0;
end else begin
- if (start_i && !locked_o) begin
+ if (start_i && !locking_o) begin
err_bits_q <= '0;
end else begin
err_bits_q <= err_bits_q | err_bits_d;
