[dv/otp_ctrl] Fix new changes in mem_bkdr_utils

Mem_bkdr_utils only can read up to the memory line width. For example,
OTP memory is 16 bits width, so we can only call read16 but not read32.

This PR separate read32 to two read16.

Signed-off-by: Cindy Chen <chencindy@opentitan.org>

hw/ip/otp_ctrl/dv/env/otp_ctrl_env_cfg.sv

diff --git a/hw/ip/otp_ctrl/dv/env/otp_ctrl_env_cfg.sv b/hw/ip/otp_ctrl/dv/env/otp_ctrl_env_cfg.sv
index 3333606..3afc045 100644
--- a/hw/ip/otp_ctrl/dv/env/otp_ctrl_env_cfg.sv
+++ b/hw/ip/otp_ctrl/dv/env/otp_ctrl_env_cfg.sv
@@ -72,4 +72,14 @@
     m_tl_agent_cfg.max_outstanding_req = 1;
   endfunction
 
+  // OTP memory width is 16 bits while OTP word is 32 bits.
+  virtual function void backdoor_write32(bit [TL_DW-1:0] addr, bit [31:0] val);
+    mem_bkdr_util_h.write16(addr,     val[15:0]);
+    mem_bkdr_util_h.write16(addr + 2, val[31:16]);
+  endfunction
+
+  virtual function bit[31:0] backdoor_read32(bit [TL_DW-1:0] addr);
+    return {mem_bkdr_util_h.read16(addr + 2), mem_bkdr_util_h.read16(addr)};
+  endfunction
+
 endclass

hw/ip/otp_ctrl/dv/env/otp_ctrl_scoreboard.sv

diff --git a/hw/ip/otp_ctrl/dv/env/otp_ctrl_scoreboard.sv b/hw/ip/otp_ctrl/dv/env/otp_ctrl_scoreboard.sv
index a270508..fd3a190 100644
--- a/hw/ip/otp_ctrl/dv/env/otp_ctrl_scoreboard.sv
+++ b/hw/ip/otp_ctrl/dv/env/otp_ctrl_scoreboard.sv
@@ -119,8 +119,8 @@
 
             if (dai_digest_ip != LifeCycleIdx) begin
               bit [TL_DW-1:0] otp_addr = PART_OTP_DIGEST_ADDRS[dai_digest_ip];
-              otp_a[otp_addr]   = cfg.mem_bkdr_util_h.read32(otp_addr << 2);
-              otp_a[otp_addr+1] = cfg.mem_bkdr_util_h.read32((otp_addr << 2) + 4);
+              otp_a[otp_addr]   = cfg.backdoor_read32(otp_addr << 2);
+              otp_a[otp_addr+1] = cfg.backdoor_read32((otp_addr << 2) + 4);
               dai_digest_ip = LifeCycleIdx;
             end
             predict_digest_csrs();
@@ -228,7 +228,7 @@
       #1ps;
       if (cfg.otp_ctrl_vif.rst_ni == 0) begin
         for (int i = 0; i < LC_PROG_DATA_SIZE/32; i++) begin
-          otp_lc_data[i*32+:32] = cfg.mem_bkdr_util_h.read32(LifeCycleOffset+i*4);
+          otp_lc_data[i*32+:32] = cfg.backdoor_read32(LifeCycleOffset + i * 4);
         end
       end
     end
@@ -1173,4 +1173,5 @@
     exp_alert = alert_name == "fatal_check_error" ? OtpCheckAlert : OtpMacroAlert;
     super.set_exp_alert(alert_name, is_fatal, max_delay);
   endfunction
+
 endclass

hw/ip/otp_ctrl/dv/env/seq_lib/otp_ctrl_base_vseq.sv

diff --git a/hw/ip/otp_ctrl/dv/env/seq_lib/otp_ctrl_base_vseq.sv b/hw/ip/otp_ctrl/dv/env/seq_lib/otp_ctrl_base_vseq.sv
index 9bbe9ec..471c824 100644
--- a/hw/ip/otp_ctrl/dv/env/seq_lib/otp_ctrl_base_vseq.sv
+++ b/hw/ip/otp_ctrl/dv/env/seq_lib/otp_ctrl_base_vseq.sv
@@ -157,7 +157,7 @@
     // If has ecc_err, backdoor write back original value
     // TODO: remove this once we can detect ECC error from men_bkdr_if
     if (backdoor_wr) begin
-      cfg.mem_bkdr_util_h.write32({addr[TL_DW-3:2], 2'b00}, backdoor_rd_val);
+      cfg.backdoor_write32({addr[TL_DW-3:2], 2'b00}, backdoor_rd_val);
     end
   endtask : dai_rd
 
@@ -252,7 +252,7 @@
     bit [TL_DW-1:0] val;
     prim_secded_pkg::secded_22_16_t out;
     addr = {addr[TL_DW-1:2], 2'b00};
-    val = cfg.mem_bkdr_util_h.read32(addr);
+    val = {cfg.mem_bkdr_util_h.read16(addr+2), cfg.mem_bkdr_util_h.read16(addr)};
     if (ecc_err == OtpNoEccErr || addr >= (LifeCycleOffset + LifeCycleSize)) return val;
 
     // Backdoor read and write back with error bits
@@ -287,7 +287,7 @@
     if (wait_done && val) csr_spinwait(ral.status.check_pending, 0);
 
     if (ecc_err != OtpNoEccErr) begin
-      cfg.mem_bkdr_util_h.write32(addr, backdoor_rd_val);
+      cfg.backdoor_write32(addr, backdoor_rd_val);
       cfg.ecc_chk_err = '{default: OtpNoEccErr};
     end
   endtask