blob: 2a426e822b8ceecbe10ac59aadd536bcfc5af245 [file] [log] [blame]
// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0
//
// interface for input data from LC, OTP and flash
interface keymgr_if(input clk, input rst_n);
import uvm_pkg::*;
import keymgr_env_pkg::*;
// Represents the keymgr sideload state for each sideload interface.
//
// The initial status is SideLoadNotAvail. After the sideload key is generated, it becomes
// SideLoadAvail.
// Status can't be directly changed from SideLoadClear to SideLoadAvail.
// When status is SideLoadClear due to SIDELOAD_CLEAR programmed, need to write CSR to 0 to reset
// it so that status is changed to SideLoadNotAvail, then we may set it to SideLoadAvail again
lc_ctrl_pkg::lc_tx_t keymgr_en;
lc_ctrl_pkg::lc_keymgr_div_t keymgr_div;
otp_ctrl_pkg::otp_device_id_t otp_device_id;
otp_ctrl_pkg::otp_keymgr_key_t otp_key;
flash_ctrl_pkg::keymgr_flash_t flash;
rom_ctrl_pkg::keymgr_data_t rom_digest;
keymgr_pkg::hw_key_req_t kmac_key;
keymgr_pkg::hw_key_req_t aes_key;
keymgr_pkg::otbn_key_req_t otbn_key;
keymgr_pkg::hw_key_req_t kmac_key_exp;
keymgr_pkg::hw_key_req_t aes_key_exp;
keymgr_pkg::otbn_key_req_t otbn_key_exp;
// connect KDF interface for assertion check
wire kmac_pkg::app_req_t kmac_data_req;
wire kmac_pkg::app_rsp_t kmac_data_rsp;
// connect EDN for assertion check
wire edn_clk, edn_rst_n, edn_req, edn_ack;
// keymgr_en is async, create a sync one for use in scb
lc_ctrl_pkg::lc_tx_t keymgr_en_sync1, keymgr_en_sync2;
// indicate if check the key is same as expected or shouldn't match to any meaningful key
// when a good KDF is ongoing or kmac sideload key is available, this flag is set to 1
bit is_kmac_key_good;
// KMAC data is checked in scb, but when keymgr is in disabled/invalid state or LC is off, KMAC
// data will be driven with constantly changed entropy data, which violate
// H_DataStableWhenValidAndNotReady_A. Use this flag to disable it
bit is_kmac_data_good;
// sideload status
keymgr_sideload_status_e aes_sideload_status;
keymgr_sideload_status_e otbn_sideload_status;
// When kmac sideload key is generated, `kmac_key` becomes valid with the generated digest data.
// If SW requests keymgr to do another operation, kmac_key will be updated to the internal key
// to perform a KMAC KDF operation.
// Once the operation is done, `kmac_key` is expected to switch automatically to the previous KMAC
// sideload key.
keymgr_sideload_status_e kmac_sideload_status;
keymgr_env_pkg::key_shares_t kmac_sideload_key_shares;
// use `string` here is to combine both internal key and sideload keys, so it could be "internal"
// or any name at keymgr_key_dest_e
keymgr_env_pkg::key_shares_t keys_a_array[keymgr_pkg::keymgr_working_state_e][keymgr_cdi_type_e][
string];
// set this flag when design enters init state, edn req will start periodically
bit start_edn_req;
// keymgr will request edn twice for 64 bit data each time, use this to indicate if it's first or
// second req. 0: wait for 1st req, 1: for 2nd
bit edn_req_cnt;
int edn_wait_cnt;
int edn_interval;
// synchronize req/ack from async domain
bit edn_req_sync;
bit edn_req_ack_sync;
bit edn_req_ack_sync_done;
localparam int CtrlCntCopies = 2;
localparam int CtrlCntWitdh = 3;
localparam int KmacIfCntWitdh = 5;
localparam int StateWidth = 10;
localparam bit [StateWidth-1:0] KmacIfValidStates = {10'b1110100010,
10'b0010011011,
10'b0101000000,
10'b1000101001,
10'b1111111101,
10'b0011101110};
localparam bit [StateWidth-1:0] CtrlValidStates = {10'b1101100001,
10'b1110010010,
10'b0011110100,
10'b0110101111,
10'b0100000100,
10'b1000011101,
10'b0001001010,
10'b1101111110,
10'b1010101000,
10'b0000110011,
10'b1011000111};
// for scb/seq to predict error/alert and sample coverage
bit is_cmd_err;
bit is_kmac_if_fsm_err;
bit is_ctrl_fsm_err;
bit is_ctrl_cnt_err;
bit is_kmac_if_cnt_err;
// invalid values
bit [2:0] force_cmds, prev_cmds;
bit [StateWidth-1:0] invalid_state, prev_state;
bit [KmacIfCntWitdh-1:0] kmac_if_invalid_cnt;
bit [CtrlCntCopies-1:0][CtrlCntWitdh:0] cnt_copies;
// If we need to wait for internal signal to be certain value, we may not be able to get that
// when the sim is close to end. Define a cnt and MaxWaitCycle to avoid sim hang
int cnt_to_wait_for_internal_value;
localparam int MaxWaitCycle = 100_000;
// Disable the check when we force internal design as it's hard to predict design behavior when
// internal FSM is changed or internal error is triggered
bit en_chk = 1;
string msg_id = "keymgr_if";
task automatic init();
// async delay as these signals are from different clock domain
#($urandom_range(1000, 0) * 1ns);
keymgr_en = lc_ctrl_pkg::On;
keymgr_div = 64'h5CFBD765CE33F34E;
otp_device_id = 'hF0F0;
otp_key = otp_ctrl_pkg::OTP_KEYMGR_KEY_DEFAULT;
flash = flash_ctrl_pkg::KEYMGR_FLASH_DEFAULT;
rom_digest.data = 256'hA20A046CF42E6EAC560A3F82BFA76285B5C1D4AEA7C915E49A32D1C89BE0F507;
rom_digest.valid = '1;
endtask
// reset local exp variables when reset is issued
function automatic void reset();
keymgr_en = lc_ctrl_pkg::lc_tx_t'($urandom);
kmac_key_exp = '0;
aes_key_exp = '0;
otbn_key_exp = '0;
is_kmac_key_good = 0;
is_kmac_data_good = 0;
kmac_sideload_status = SideLoadNotAvail;
aes_sideload_status = SideLoadNotAvail;
otbn_sideload_status = SideLoadNotAvail;
// edn related
edn_interval = 'h100;
start_edn_req = 0;
is_cmd_err = 0;
is_kmac_if_fsm_err = 0;
is_ctrl_fsm_err = 0;
is_ctrl_cnt_err = 0;
is_kmac_if_cnt_err = 0;
endfunction
// randomize otp, lc, flash input data
task automatic drive_random_hw_input_data(int num_invalid_input = 0);
lc_ctrl_pkg::lc_keymgr_div_t local_keymgr_div;
bit [keymgr_pkg::DevIdWidth-1:0] local_otp_device_id;
otp_ctrl_pkg::otp_keymgr_key_t local_otp_key;
flash_ctrl_pkg::keymgr_flash_t local_flash;
rom_ctrl_pkg::keymgr_data_t local_rom_digest;
// async delay as these signals are from different clock domain
#($urandom_range(1000, 0) * 1ns);
// randomize all data to be non all 0s or 1s
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_keymgr_div,
!(local_keymgr_div inside {0, '1});, , msg_id)
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_otp_device_id,
!(local_otp_device_id inside {0, '1});, , msg_id)
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_otp_key,
local_otp_key.valid == 1;
!(local_otp_key.key_share0 inside {0, '1});
!(local_otp_key.key_share1 inside {0, '1});, , msg_id)
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_flash,
foreach (local_flash.seeds[i]) {
!(local_flash.seeds[i] inside {0, '1});
}, , msg_id)
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_rom_digest,
local_rom_digest.valid == 1;
!(local_rom_digest.data inside {0, '1});, , msg_id)
// make HW input to be all 0s or 1s
repeat (num_invalid_input) begin
randcase
1: begin
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_keymgr_div,
local_keymgr_div inside {0, '1};, , msg_id)
end
1: begin
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_otp_device_id,
local_otp_device_id inside {0, '1};, , msg_id)
end
1: begin
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_otp_key,
!local_otp_key.valid;, , msg_id)
end
1: begin
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_otp_key,
local_otp_key.valid;
local_otp_key.key_share0 inside {0, '1} ||
local_otp_key.key_share1 inside {0, '1};, , msg_id)
end
1: begin
int idx = $urandom_range(0, flash_ctrl_pkg::NumSeeds - 1);
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_flash,
local_flash.seeds[idx] inside {0, '1};, , msg_id)
end
1: begin
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_rom_digest,
!local_rom_digest.valid;, , msg_id)
end
1: begin
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(local_rom_digest,
local_rom_digest.valid == 1;
local_rom_digest.data inside {0, '1};, , msg_id)
end
endcase
end
keymgr_div = local_keymgr_div;
otp_device_id = local_otp_device_id;
otp_key = local_otp_key;
flash = local_flash;
rom_digest = local_rom_digest;
// a few cycles design to sync up these inputs, before we start operations
repeat ($urandom_range(3, 100)) @(posedge clk);
endtask
// update kmac key for comparison during KDF
function automatic void update_kdf_key(keymgr_env_pkg::key_shares_t key_shares,
keymgr_pkg::keymgr_working_state_e state,
bit good_key, bit good_data);
kmac_key_exp <= '{1'b1, key_shares};
is_kmac_key_good <= good_key;
is_kmac_data_good <= good_data;
endfunction
// store internal key once it's available and use to compare if future OP is invalid
function automatic void store_internal_key(keymgr_env_pkg::key_shares_t key_shares,
keymgr_pkg::keymgr_working_state_e state,
keymgr_cdi_type_e cdi_type);
keys_a_array[state][cdi_type]["Internal"] = key_shares;
endfunction
// update sideload key for comparison
// if it's good key, store it to compare for future invalid OP
function automatic void update_sideload_key(keymgr_env_pkg::kmac_digests_t key_shares,
keymgr_pkg::keymgr_working_state_e state,
keymgr_cdi_type_e cdi_type,
keymgr_pkg::keymgr_key_dest_e dest = keymgr_pkg::Kmac
);
keymgr_env_pkg::key_shares_t trun_key_shares = {key_shares[1][keymgr_pkg::KeyWidth-1:0],
key_shares[0][keymgr_pkg::KeyWidth-1:0]};
case (dest)
keymgr_pkg::Kmac: begin
if (kmac_sideload_status != SideLoadClear) begin
kmac_sideload_status <= SideLoadAvail;
kmac_key_exp <= '{1'b1, trun_key_shares};
is_kmac_key_good <= 1;
kmac_sideload_key_shares <= trun_key_shares;
end
end
keymgr_pkg::Aes: begin
if (aes_sideload_status != SideLoadClear) begin
aes_key_exp <= '{1'b1, trun_key_shares};
aes_sideload_status <= SideLoadAvail;
end
end
keymgr_pkg::Otbn: begin
if (otbn_sideload_status != SideLoadClear) begin
// only otbn uses full 384 bits digest data
otbn_key_exp <= '{1'b1, key_shares};
otbn_sideload_status <= SideLoadAvail;
end
end
default: `uvm_fatal("keymgr_if", $sformatf("Unexpect dest type %0s", dest.name))
endcase
keys_a_array[state][cdi_type][dest.name] = trun_key_shares;
endfunction
function automatic void clear_sideload_key(keymgr_pkg::keymgr_sideload_clr_e clear_dest);
// reset from Clear to NotAvail
if (kmac_sideload_status == SideLoadClear) kmac_sideload_status <= SideLoadNotAvail;
if (aes_sideload_status == SideLoadClear) aes_sideload_status <= SideLoadNotAvail;
if (otbn_sideload_status == SideLoadClear) otbn_sideload_status <= SideLoadNotAvail;
case (clear_dest)
keymgr_pkg::SideLoadClrIdle: ; // do nothing
keymgr_pkg::SideLoadClrAes, keymgr_pkg::SideLoadClrKmac, keymgr_pkg::SideLoadClrOtbn: begin
clear_one_sideload_key(clear_dest);
end
// clear all
default: begin
clear_one_sideload_key(keymgr_pkg::SideLoadClrAes);
clear_one_sideload_key(keymgr_pkg::SideLoadClrKmac);
clear_one_sideload_key(keymgr_pkg::SideLoadClrOtbn);
end
endcase
endfunction
function automatic void clear_one_sideload_key(keymgr_pkg::keymgr_sideload_clr_e clear_dest);
case (clear_dest)
keymgr_pkg::SideLoadClrAes: begin
aes_sideload_status <= SideLoadClear;
aes_key_exp.valid <= 0;
end
keymgr_pkg::SideLoadClrKmac: begin
is_kmac_key_good <= 0;
kmac_key_exp.valid <= 0;
kmac_sideload_status <= SideLoadClear;
end
keymgr_pkg::SideLoadClrOtbn: begin
otbn_sideload_status <= SideLoadClear;
otbn_key_exp.valid <= 0;
end
default: begin
`uvm_fatal(msg_id, $sformatf("Unexpected clear_dest %0d", clear_dest))
end
endcase
endfunction
function automatic bit get_keymgr_en();
return keymgr_en_sync2 === lc_ctrl_pkg::On;
endfunction
function automatic void wipe_sideload_keys();
is_kmac_key_good <= 0;
aes_key_exp.valid <= 0;
kmac_key_exp.valid <= 0;
otbn_key_exp.valid <= 0;
aes_sideload_status <= SideLoadClear;
kmac_sideload_status <= SideLoadClear;
otbn_sideload_status <= SideLoadClear;
endfunction
// TODO, create a more generic approach to verify sec_cm
task automatic force_cmd_err();
@(posedge clk);
randcase
// force more than one force_cmds are issued
1: begin
`uvm_info(msg_id, "Force cmd", UVM_LOW)
prev_cmds = {tb.dut.u_ctrl.gen_en_o, tb.dut.u_ctrl.id_en_o, tb.dut.u_ctrl.adv_en_o};
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(force_cmds, $countones(force_cmds) > 1;, , msg_id)
// these signals are wires, need force and then release at reset
if (force_cmds[0]) force tb.dut.u_ctrl.adv_en_o = 1;
if (force_cmds[1]) force tb.dut.u_ctrl.id_en_o = 1;
if (force_cmds[2]) force tb.dut.u_ctrl.gen_en_o = 1;
@(posedge clk);
if ($urandom_range(0, 1)) begin
if (force_cmds[0]) force tb.dut.u_ctrl.adv_en_o = prev_cmds[0];
if (force_cmds[1]) force tb.dut.u_ctrl.id_en_o = prev_cmds[1];
if (force_cmds[2]) force tb.dut.u_ctrl.gen_en_o = prev_cmds[2];
@(posedge clk);
end
if (force_cmds[0]) release tb.dut.u_ctrl.adv_en_o;
if (force_cmds[1]) release tb.dut.u_ctrl.id_en_o;
if (force_cmds[2]) release tb.dut.u_ctrl.gen_en_o;
is_cmd_err = 1;
end
1: begin
`uvm_info(msg_id, "Force KMC_IF FSM", UVM_LOW)
prev_state = tb.dut.u_kmac_if.u_state_regs.state_raw;
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(invalid_state,
!(invalid_state inside {KmacIfValidStates});,
, msg_id)
force tb.dut.u_kmac_if.u_state_regs.state_raw = invalid_state;
@(posedge clk);
if ($urandom_range(0, 1)) begin
force tb.dut.u_kmac_if.u_state_regs.state_raw = prev_state;
@(posedge clk);
end
release tb.dut.u_kmac_if.u_state_regs.state_raw;
is_kmac_if_fsm_err = 1;
end
1: begin
`uvm_info(msg_id, "Force KMC_IF cnt", UVM_LOW)
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(kmac_if_invalid_cnt,
kmac_if_invalid_cnt inside {[1 : 16]};,
, msg_id)
// wait for cnt to match a the picked value
cnt_to_wait_for_internal_value = 0;
while (1) begin
@(negedge clk);
if (tb.dut.u_kmac_if.u_cnt.up_cnt_q == kmac_if_invalid_cnt) begin
break;
end else if (cnt_to_wait_for_internal_value < MaxWaitCycle) begin
cnt_to_wait_for_internal_value++;
end else begin
return;
end
end
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(kmac_if_invalid_cnt,
kmac_if_invalid_cnt != tb.dut.u_kmac_if.u_cnt.up_cnt_q;,
, msg_id)
$deposit(tb.dut.u_kmac_if.u_cnt.up_cnt_q, kmac_if_invalid_cnt);
@(posedge clk);
if ($urandom_range(0, 1)) begin
@(negedge clk);
$deposit(tb.dut.u_kmac_if.u_cnt.up_cnt_q, kmac_if_invalid_cnt + 1);
@(posedge clk);
end
is_kmac_if_cnt_err = 1;
end
1: begin
`uvm_info(msg_id, "Force ctrl FSM", UVM_LOW)
prev_state = tb.dut.u_ctrl.u_state_regs.state_raw;
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(invalid_state,
!(invalid_state inside {CtrlValidStates});,
, msg_id)
force tb.dut.u_ctrl.u_state_regs.state_raw = invalid_state;
@(posedge clk);
if ($urandom_range(0, 1)) begin
force tb.dut.u_ctrl.u_state_regs.state_raw = prev_state;
@(posedge clk);
end
release tb.dut.u_ctrl.u_state_regs.state_raw;
is_ctrl_fsm_err = 1;
end
1: begin
`uvm_info(msg_id, "Force ctrl cnt", UVM_LOW)
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(cnt_copies,
cnt_copies[0] != cnt_copies[1];,
, msg_id)
$deposit(tb.dut.u_ctrl.u_cnt.up_cnt_q, cnt_copies);
@(posedge clk);
if ($urandom_range(0, 1)) begin
@(negedge clk);
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(cnt_copies,
cnt_copies[0] == cnt_copies[1];,
, msg_id)
$deposit(tb.dut.u_ctrl.u_cnt.up_cnt_q, cnt_copies);
@(posedge clk);
end
is_ctrl_cnt_err = 1;
end
endcase
endtask
// Disable h_data stability assertion when keymgr is in disabled/invalid state or LC turns off as
// keymgr will sent constantly changed entropy data to KMAC for KDF operation.
always_comb begin
if (!is_kmac_data_good || keymgr_en_sync1 != lc_ctrl_pkg::On) begin
$assertoff(0, tb.keymgr_kmac_intf.req_data_if.H_DataStableWhenValidAndNotReady_A);
end else begin
$asserton(0, tb.keymgr_kmac_intf.req_data_if.H_DataStableWhenValidAndNotReady_A);
end
end
always_ff @(posedge clk or negedge rst_n) begin
if (!rst_n) begin
keymgr_en_sync1 <= lc_ctrl_pkg::Off;
keymgr_en_sync2 <= lc_ctrl_pkg::Off;
end else begin
keymgr_en_sync1 <= keymgr_en;
// avoid race condtion in the driver
keymgr_en_sync2 <= #1ps keymgr_en_sync1;
end
end
// if kmac sideload key is available, switch to it after an operation is completed
// if not available, de-assert valid after done is asserted
initial begin
forever begin
@(posedge clk);
if (kmac_data_rsp.done) begin
if (kmac_sideload_status == SideLoadAvail) begin
kmac_key_exp <= '{1'b1, kmac_sideload_key_shares};
is_kmac_key_good <= 1;
end else begin
kmac_key_exp.valid <= 0;
is_kmac_key_good <= 0;
end
end // kmac_data_rsp.done
end // forever
end
// check if key is invalid, it should not match to any of the meaningful keys
initial begin
fork
forever begin
@(kmac_key or is_kmac_key_good);
// one cycle to sync with clock, one cycle to allow design to clear the key
repeat (2) @(posedge clk);
if (!is_kmac_key_good) check_invalid_key(kmac_key, "KMAC");
end
forever begin
@(aes_key or aes_sideload_status);
// one cycle to sync with clock, one cycle to allow design to clear the key
repeat (2) @(posedge clk);
if (aes_sideload_status != SideLoadAvail) check_invalid_key(aes_key, "AES");
end
forever begin
@(otbn_key or otbn_sideload_status);
// one cycle to sync with clock, one cycle to allow design to clear the key
repeat (2) @(posedge clk);
if (otbn_sideload_status != SideLoadAvail) check_invalid_key(otbn_key, "OTBN");
end
join
end
function automatic void check_invalid_key(keymgr_pkg::hw_key_req_t act_key, string key_name);
if (rst_n && act_key.valid && en_chk) begin
foreach (keys_a_array[state, cdi, dest]) begin
`DV_CHECK_CASE_NE({act_key.key[1], act_key.key[0]}, keys_a_array[state][cdi][dest],
$sformatf("%s key at state %s for %s %s", key_name, state.name, cdi.name, dest), ,
msg_id)
// once key is wiped, 2 shares will be wiped to different values
`DV_CHECK_CASE_NE(act_key.key[1], act_key.key[0],
$sformatf("%s key at state %s for %s %s", key_name, state.name, cdi.name, dest), ,
msg_id)
end
end
endfunction
// Create a macro to skip checking key values when LC is off or fault error occurs
`define ASSERT_IFF_KEYMGR_LEGAL(NAME, SEQ) \
`ASSERT(NAME, SEQ, clk, !rst_n || keymgr_en_sync2 != lc_ctrl_pkg::On || !en_chk)
`ASSERT_IFF_KEYMGR_LEGAL(CheckKmacKey, is_kmac_key_good && kmac_key_exp.valid ->
kmac_key == kmac_key_exp)
`ASSERT_IFF_KEYMGR_LEGAL(CheckKmacKeyValid, is_kmac_key_good ->
kmac_key_exp.valid == kmac_key.valid)
`ASSERT_IFF_KEYMGR_LEGAL(CheckAesKey, aes_sideload_status == SideLoadAvail && aes_key_exp.valid ->
aes_key == aes_key_exp)
`ASSERT_IFF_KEYMGR_LEGAL(CheckAesKeyValid, aes_sideload_status != SideLoadClear ->
aes_key_exp.valid == aes_key.valid)
`ASSERT_IFF_KEYMGR_LEGAL(CheckOtbnKey, otbn_sideload_status == SideLoadAvail && otbn_key_exp.valid
-> otbn_key == otbn_key_exp)
`ASSERT_IFF_KEYMGR_LEGAL(CheckOtbnKeyValid, otbn_sideload_status != SideLoadClear ->
otbn_key_exp.valid == otbn_key.valid)
// for EDN assertion
// sync req/ack to core clk domain
always @(posedge edn_clk or negedge edn_rst_n) begin
if (!edn_rst_n) begin
edn_req_sync <= 0;
edn_req_ack_sync <= 0;
end else if (edn_req_ack_sync_done) begin
edn_req_sync <= 0;
edn_req_ack_sync <= 0;
end else if (edn_req && !edn_req_sync) begin
edn_req_sync <= 1;
end else if (edn_req & edn_ack) begin
edn_req_ack_sync <= 1;
end
end
// use start_edn_req to skip checking 1st EDN req as it's triggered by advance cmd
always @(posedge clk or negedge rst_n) begin
if (!rst_n) begin
edn_req_ack_sync_done <= 0;
start_edn_req <= 0;
end else if (edn_req_ack_sync && !edn_req_ack_sync_done) begin
edn_req_ack_sync_done <= 1;
start_edn_req <= 1;
end else if (!edn_req_ack_sync) begin
edn_req_ack_sync_done <= 0;
end
end
always @(posedge clk or negedge rst_n) begin
if (!rst_n) begin
edn_wait_cnt <= 0;
end else if (!edn_req_sync) begin
edn_wait_cnt <= edn_wait_cnt + 1;
end else begin
edn_wait_cnt <= 0;
end
end
initial begin
forever begin
wait(rst_n === 1);
edn_req_cnt <= 0;
`DV_SPINWAIT_EXIT(forever begin
@(negedge edn_req_ack_sync_done);
edn_req_cnt <= edn_req_cnt + 1;
end,
wait(!rst_n), , msg_id)
end
end
// consider async handshaking and a few cycles to start the req. allow no more than 20 tolerance
// error on the cnt
`ASSERT(CheckEdn1stReq, $rose(edn_req_sync) && edn_req_cnt == 0 && start_edn_req |->
(edn_wait_cnt > edn_interval) && (edn_wait_cnt - edn_interval < 20), clk, !rst_n)
`ASSERT(CheckEdn2ndReq, $rose(edn_req_sync) && edn_req_cnt == 1 |-> edn_wait_cnt < 20,
clk, !rst_n)
`undef ASSERT_IFF_KEYMGR_LEGAL
endinterface