| // Copyright lowRISC contributors. |
| // Licensed under the Apache License, Version 2.0, see LICENSE for details. |
| // SPDX-License-Identifier: Apache-2.0 |
| // |
| // Key manager CFGEN |
| // TBD This should be enhanced in the future to contain a shadow copy |
| |
| `include "prim_assert.sv" |
| |
| module keymgr_cfg_en #( |
| // controls whether clear has an effect on output value during non-init |
| parameter bit NonInitClr = 1'b1 |
| ) ( |
| input clk_i, |
| input rst_ni, |
| input init_i, |
| input en_i, |
| input set_i, |
| input clr_i, |
| output logic out_o |
| ); |
| |
| logic out_q; |
| logic init_q; |
| |
| logic vld_clr; |
| logic vld_set; |
| logic vld_dis; |
| |
| assign vld_clr = init_q && clr_i; |
| assign vld_set = init_q && set_i; |
| assign vld_dis = init_q && !en_i; |
| |
| // the same cycle where clear is asserted should already block future |
| // configuration |
| logic out_clr; |
| assign out_clr = NonInitClr ? clr_i : vld_clr; |
| assign out_o = ~out_clr & out_q & en_i; |
| |
| always_ff @(posedge clk_i or negedge rst_ni) begin |
| if (!rst_ni) begin |
| init_q <= '0; |
| end else if (init_q && !en_i) begin |
| init_q <= '0; |
| end else if (init_i && en_i) begin |
| init_q <= 1'b1; |
| end |
| end |
| |
| // clearing the configure enable always has higher priority than setting |
| always_ff @(posedge clk_i or negedge rst_ni) begin |
| if (!rst_ni) begin |
| out_q <= 1'b1; |
| end else if (vld_dis) begin |
| out_q <= 1'b0; |
| end else if (vld_set) begin |
| out_q <= 1'b1; |
| end else if (out_clr) begin |
| out_q <= 1'b0; |
| end |
| end |
| |
| endmodule // keymgr_cfg_en |