[keymgr] latch one-hot error when it happens
Address #5363
Signed-off-by: Timothy Chen <timothytim@google.com>
diff --git a/hw/ip/keymgr/rtl/keymgr_kmac_if.sv b/hw/ip/keymgr/rtl/keymgr_kmac_if.sv
index adbf665..5194c21 100644
--- a/hw/ip/keymgr/rtl/keymgr_kmac_if.sv
+++ b/hw/ip/keymgr/rtl/keymgr_kmac_if.sv
@@ -278,8 +278,21 @@
logic [2:0] enables, enables_sub;
assign enables = {adv_en_i, id_en_i, gen_en_i};
assign enables_sub = enables - 1'b1;
+
+ // if a one hot error occurs, latch onto it permanently
+ logic one_hot_err_q, one_hot_err_d;
+ assign one_hot_err_d = |(enables & enables_sub);
+
+ always_ff @(posedge clk_i or negedge rst_ni) begin
+ if (!rst_ni) begin
+ one_hot_err_q <= '0;
+ end else if (one_hot_err_d) begin
+ one_hot_err_q <= '1;
+ end
+ end
+
// command error occurs if kmac errors or if the command itself is invalid
- assign cmd_error_o = |(enables & enables_sub);
+ assign cmd_error_o = one_hot_err_q;
// request entropy to churn whenever a transaction is accepted
assign prng_en_o = kmac_data_o.valid & kmac_data_i.ready;
