cv32e40s_debug_triggers.sv

// Copyright 2022 Silicon Labs, Inc.
//
// This file, and derivatives thereof are licensed under the
// Solderpad License, Version 2.0 (the "License").
//
// Use of this file means you agree to the terms and conditions
// of the license and are in full compliance with the License.
//
// You may obtain a copy of the License at:
//
//     https://solderpad.org/licenses/SHL-2.0/
//
// Unless required by applicable law or agreed to in writing, software
// and hardware implementations thereof distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED.
//
// See the License for the specific language governing permissions and
// limitations under the License.

////////////////////////////////////////////////////////////////////////////////
// Engineer:       Oystein Knauserud - oystein.knauserud@silabs.com           //
//                                                                            //
// Design Name:    Debug triggers                                             //
// Project Name:   CV32E40S                                                   //
// Language:       SystemVerilog                                              //
//                                                                            //
// Description:    Module containing 0-4 triggers for debug                   //
//                                                                            //
////////////////////////////////////////////////////////////////////////////////

module cv32e40s_debug_triggers
import cv32e40s_pkg::*;
#(
  parameter     LIB              = 0,
  parameter int DBG_NUM_TRIGGERS = 1
)
(
  input  logic       clk,
  input  logic       rst_n,
  input  logic       scan_cg_en_i,

  // CSR inputs write inputs
  input  logic [31:0] csr_wdata_i,
  input  logic        tselect_we_i,
  input  logic        tdata1_we_i,
  input  logic        tdata2_we_i,
  input  logic        tinfo_we_i,

  // CSR read data outputs
  output logic [31:0] tselect_rdata_o,
  output logic [31:0] tdata1_rdata_o,
  output logic [31:0] tdata2_rdata_o,
  output logic [31:0] tinfo_rdata_o,

  // IF stage inputs
  input  logic [31:0] pc_if_i,
  input  logic        ptr_in_if_i,
  input  privlvl_t    priv_lvl_if_i,

  // EX stage / LSU inputs
  input  logic        lsu_valid_ex_i,
  input  logic [31:0] lsu_addr_ex_i,
  input  logic        lsu_we_ex_i,
  input  logic [3:0]  lsu_be_ex_i,
  input  privlvl_t    priv_lvl_ex_i,

  // WB stage inputs
  input  privlvl_t    priv_lvl_wb_i,

  // Controller inputs
  input ctrl_fsm_t    ctrl_fsm_i,

  // Trigger match outputs
  output logic [31:0] trigger_match_if_o,  // Instruction address match
  output logic [31:0] trigger_match_ex_o,  // Load/Store address match
  output logic        etrigger_wb_o        // Exception trigger match
);

  // Set mask for supported exception codes for exception triggers.
  localparam logic [31:0] ETRIGGER_TDATA2_MASK = (1 << EXC_CAUSE_INSTR_BUS_FAULT) | (1 << EXC_CAUSE_INSTR_INTEGRITY_FAULT) | (1 << EXC_CAUSE_ECALL_MMODE) | ((USER) << EXC_CAUSE_ECALL_UMODE) | (1 << EXC_CAUSE_STORE_FAULT) |
                                                 (1 << EXC_CAUSE_LOAD_FAULT) | (1 << EXC_CAUSE_BREAKPOINT) | (1 << EXC_CAUSE_ILLEGAL_INSN) | (1 << EXC_CAUSE_INSTR_FAULT);


  // CSR write data
  logic [31:0] tselect_n;
  logic [31:0] tdata2_n;
  logic [31:0] tinfo_n;

  // RVFI only signals
  logic [31:0] tdata1_n_r;
  logic [31:0] tdata2_n_r;
  logic        tdata1_we_r;
  logic        tdata2_we_r;


  // Signal for or'ing unused signals for easier lint
  logic unused_signals;



  generate
    if (DBG_NUM_TRIGGERS > 0) begin : gen_triggers
      // Internal CSR write enables
      logic [DBG_NUM_TRIGGERS-1 : 0] tdata1_we_int;
      logic [DBG_NUM_TRIGGERS-1 : 0] tdata1_we_hit;
      logic [DBG_NUM_TRIGGERS-1 : 0] tdata2_we_int;

      // Next-values for tdata1
      logic [31:0] tdata1_n[DBG_NUM_TRIGGERS];

      // CSR instance outputs
      logic [31:0] tdata1_q[DBG_NUM_TRIGGERS];
      logic [31:0] tdata2_q[DBG_NUM_TRIGGERS];
      logic [31:0] tselect_q;

      // Shadowcopy rd_error outputs
      logic [DBG_NUM_TRIGGERS-1 :0] tdata1_rd_error;
      logic [DBG_NUM_TRIGGERS-1 :0] tdata2_rd_error;
      logic                         tselect_rd_error;

      // Fetch stage trigger match
      // CSR read data, possibly WARL resolved
      logic [31:0] tdata1_rdata[DBG_NUM_TRIGGERS];
      logic [31:0] tdata2_rdata[DBG_NUM_TRIGGERS];

      // IF, EX and WB stages trigger match
      logic [DBG_NUM_TRIGGERS-1 : 0] trigger_match_if;
      logic [DBG_NUM_TRIGGERS-1 : 0] trigger_match_ex;
      logic [DBG_NUM_TRIGGERS-1 : 0] etrigger_wb;

      // Instruction address match
      logic [DBG_NUM_TRIGGERS-1 : 0] if_addr_match;

      // LSU address match signals
      logic [DBG_NUM_TRIGGERS-1 : 0] lsu_addr_match_en;
      logic [DBG_NUM_TRIGGERS-1 : 0] lsu_addr_match;
      logic [3:0]                    lsu_byte_addr_match[DBG_NUM_TRIGGERS];

      // Enable matching based on privilege level per trigger
      logic [DBG_NUM_TRIGGERS-1 : 0] priv_lvl_match_en_if;
      logic [DBG_NUM_TRIGGERS-1 : 0] priv_lvl_match_en_ex;
      logic [DBG_NUM_TRIGGERS-1 : 0] priv_lvl_match_en_wb;

      logic [1:0]  lsu_addr_low_lsb;  // Lower two bits of the lowest accessed address
      logic [1:0]  lsu_addr_high_lsb; // Lower two bits of the highest accessed address
      logic [31:0] lsu_addr_low;      // The lowest accessed address of an LSU transaction
      logic [31:0] lsu_addr_high;     // The highest accessed address of an LSU transaction

      // Exception trigger code match
      logic [31:0] exception_match[DBG_NUM_TRIGGERS];

      // Resolve hit1+hit0 of mcontrol6
      logic [1:0] mcontrol6_hit_resolved[DBG_NUM_TRIGGERS];


      // Write data
      // tdata1 has one _n value per implemented trigger to enable updating all hit-fields of
      // mcontrol6 at the same time.
      for (genvar idx=0; idx<DBG_NUM_TRIGGERS; idx++) begin : tdata1_wdata
        always_comb begin
          tdata1_n[idx]  = tdata1_rdata[idx];
          tdata1_we_hit[idx] = 1'b0;

          mcontrol6_hit_resolved[idx] = mcontrol6_hit_resolve({tdata1_rdata[idx][MCONTROL_6_HIT1], tdata1_rdata[idx][MCONTROL_6_HIT0]},
                                                              {csr_wdata_i[MCONTROL_6_HIT1], csr_wdata_i[MCONTROL_6_HIT0]});
          if (tdata1_we_i && (tselect_rdata_o == idx)) begin
            if (csr_wdata_i[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL) begin
              // Mcontrol supports any value in tdata2, no need to check tdata2 before writing tdata1
              tdata1_n[idx] = {
                                TTYPE_MCONTROL,        // type    : address/data match
                                1'b1,                  // dmode   : access from D mode only
                                6'b000000,             // maskmax  : hardwired to zero
                                1'b0,                  // hit     : hardwired to zero
                                1'b0,                  // select  : hardwired to zero, only address matching
                                1'b0,                  // timing  : hardwired to zero, only 'before' timing
                                2'b00,                 // sizelo  : hardwired to zero, match any size
                                4'b0001,               // action  : enter debug on match
                                1'b0,                  // chain   : hardwired to zero
                                mcontrol2_6_match_resolve(csr_wdata_i[MCONTROL2_6_MATCH_HIGH:MCONTROL2_6_MATCH_LOW]), // match, WARL(0,2,3) 10:7
                                csr_wdata_i[6],        // m       : match in machine mode
                                1'b0,                  //         : hardwired to zero
                                1'b0,                  // s       : hardwired to zer0
                                mcontrol2_6_u_resolve(csr_wdata_i[MCONTROL2_6_U]),     // zero, U 3
                                csr_wdata_i[2],        // EXECUTE 2
                                csr_wdata_i[1],        // STORE 1
                                csr_wdata_i[0]         // LOAD 0
                            };
            end else if (csr_wdata_i[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL6) begin
              // Mcontrol6 supports any value in tdata2, no need to check tdata2 before writing tdata1
              tdata1_n[idx] = {
                                TTYPE_MCONTROL6,       // type    : address/data match
                                1'b1,                  // dmode   : access from D mode only
                                mcontrol6_uncertain_resolve(csr_wdata_i[MCONTROL_6_UNCERTAIN]), // uncertain  26
                                mcontrol6_hit_resolved[idx][1], // hit1: 25
                                2'b00,                // zero, vs, vu
                                mcontrol6_hit_resolved[idx][0], // hit0: 22
                                1'b0,                  // zero, select 21
                                2'b00,                 // zero, 20:19
                                3'b000,                // zero, size (match any size) 18:16
                                4'b0001,               // action, WARL(1), enter debug 15:12
                                1'b0,                  // zero, chain 11
                                mcontrol2_6_match_resolve(csr_wdata_i[MCONTROL2_6_MATCH_HIGH:MCONTROL2_6_MATCH_LOW]), // match, WARL(0,2,3) 10:7
                                csr_wdata_i[6],        // M  6
                                mcontrol6_uncertainen_resolve(csr_wdata_i[MCONTROL_6_UNCERTAINEN]), // uncertainen 5
                                1'b0,                  // zero, S 4
                                mcontrol2_6_u_resolve(csr_wdata_i[MCONTROL2_6_U]),     // zero, U 3
                                csr_wdata_i[2],        // EXECUTE 2
                                csr_wdata_i[1],        // STORE 1
                                csr_wdata_i[0]         // LOAD 0
                              };
            end else if (csr_wdata_i[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_ETRIGGER) begin
              // Etrigger can only support a subset of possible values in tdata2, only update tdata1 if
              // tdata2 contains a legal value for etrigger.

              // Detect if any cleared bits in ETRIGGER_TDATA2_MASK are set in tdata2
              if (|(tdata2_rdata_o & (~ETRIGGER_TDATA2_MASK))) begin
                // Unsupported exception codes enabled, default to disabled trigger.
                tdata1_n[idx] = {TTYPE_DISABLED, 1'b1, {27{1'b0}}};
              end else begin
                tdata1_n[idx] = {
                                  TTYPE_ETRIGGER,        // type  : exception trigger
                                  1'b1,                  // dmode : access from D mode only 27
                                  1'b0,                  // hit   : WARL(0) 26
                                  13'h0,                 // zero  : tied to zero 25:13
                                  1'b0,                  // vs    : WARL(0) 12
                                  1'b0,                  // vu    : WARL(0) 11
                                  1'b0,                  // zero  : tied to zero 10
                                  csr_wdata_i[9],        // m     : Match in machine mode 9
                                  1'b0,                  // zero  : tied to zero 8
                                  1'b0,                  // s     : WARL(0) 7
                                  etrigger_u_resolve(csr_wdata_i[ETRIGGER_U]), // u     : Match in user mode 6
                                  6'b000001              // action : WARL(1), enter debug on match
                                };
              end
            end else if (csr_wdata_i[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_DISABLED) begin
              // All tdata2 values are legal for a disabled trigger, no WARL on tdata1.
              tdata1_n[idx] = {TTYPE_DISABLED, 1'b1, {27{1'b0}}};
            end else begin
              // No legal trigger type, set disabled trigger type 0xF
              tdata1_n[idx] = {TTYPE_DISABLED, 1'b1, {27{1'b0}}};
            end
          end // tdata1_we_i

          // SW writes and writes from controller cannot happen at the same time.
          // Update bits {hit1, hit0} (WARL 0x0, 0x1)
          if (ctrl_fsm_i.debug_trigger_hit_update) begin
            if (tdata1_rdata[idx][TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL6) begin
              if (ctrl_fsm_i.debug_trigger_hit[idx]) begin
                tdata1_n[idx][MCONTROL_6_HIT1]  = 1'b0;
                tdata1_n[idx][MCONTROL_6_HIT0]  = 1'b1;
                tdata1_we_hit[idx]              = 1'b1;
              end
            end
          end
        end
      end //for

      // Write data for tdata2 and tselect
      always_comb begin
        // Tselect is WARL (0 -> DBG_NUM_TRIGGERS-1)
        tselect_n = (csr_wdata_i < DBG_NUM_TRIGGERS) ? csr_wdata_i : tselect_rdata_o;
        tdata2_n  = tdata2_rdata_o;

        // tdata2
        if (tdata2_we_i) begin
          if ((tdata1_rdata_o[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_DISABLED) ||
              (tdata1_rdata_o[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL) ||
              (tdata1_rdata_o[TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL6)) begin
            // Disabled trigger, mcontrol and mcontrol6 can have any value in tdata2
            tdata2_n = csr_wdata_i;
          end else begin
            // Exception trigger, only allow implemented exception codes to be used
            tdata2_n = csr_wdata_i & ETRIGGER_TDATA2_MASK;
          end
        end // tdata2_we_i

        tinfo_n       = tinfo_rdata_o;    // Read only
      end

      // Calculate highest and lowest value of address[1:0] based on lsu_be_ex_i
      always_comb begin
        lsu_addr_high_lsb = 2'b00;
        lsu_addr_low_lsb  = 2'b00;
        // Find highest accessed byte
        for (int b=0; b<4; b++) begin : gen_high_byte_checks
          if (lsu_be_ex_i[b]) begin
            lsu_addr_high_lsb = 2'(b);
          end // if
        end // for

        // Find lowest accessed byte
        for (int b=3; b>=0; b--) begin : gen_low_byte_checks
          if (lsu_be_ex_i[b]) begin
            lsu_addr_low_lsb = 2'(b);
          end // if
        end // for
      end // always

      assign lsu_addr_high = {lsu_addr_ex_i[31:2], lsu_addr_high_lsb};
      assign lsu_addr_low =  {lsu_addr_ex_i[31:2], lsu_addr_low_lsb};

      // Generate DBG_NUM_TRIGGERS instances of tdata1, tdata2 and match checks
      for (genvar idx=0; idx<DBG_NUM_TRIGGERS; idx++) begin : tmatch_csr

        ////////////////////////////////////
        // Instruction address match (IF)
        ////////////////////////////////////

        // With timing=0 we enter debug before executing the instruction at the match address. We use the IF stage PC
        // for comparison, and any trigger match will cause the instruction to act as a NOP with no side effects until it
        // reaches WB where debug mode is entered.
        //
        // Trigger match is disabled while in debug mode.
        //
        // Trigger CSRs can only be written from debug mode, writes from any other privilege level are ignored.
        //   Thus we do not have an issue where a write to the tdata2 CSR immediately before the matched instruction
        //   could be missed since we must write in debug mode, then dret to machine mode (kills pipeline) before
        //   returning to dpc.
        //   No instruction address match on any pointer type (CLIC and Zc tablejumps).

        // Check for address match using tdata2.match for checking rule
        assign if_addr_match[idx] = (tdata1_rdata[idx][MCONTROL2_6_MATCH_HIGH:MCONTROL2_6_MATCH_LOW] == 4'h0) ? (pc_if_i == tdata2_rdata[idx]) :
                                    (tdata1_rdata[idx][MCONTROL2_6_MATCH_HIGH:MCONTROL2_6_MATCH_LOW] == 4'h2) ? (pc_if_i >= tdata2_rdata[idx]) : (pc_if_i < tdata2_rdata[idx]);

        // Check if matching is enabled for the current privilege level from IF
        assign priv_lvl_match_en_if[idx] = (tdata1_rdata[idx][MCONTROL2_6_M] && (priv_lvl_if_i == PRIV_LVL_M)) ||
                                           (tdata1_rdata[idx][MCONTROL2_6_U] && (priv_lvl_if_i == PRIV_LVL_U));

        // Check for trigger match from IF
        assign trigger_match_if[idx] = ((tdata1_rdata[idx][TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL)   ||
                                        (tdata1_rdata[idx][TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL6)) &&
                                       tdata1_rdata[idx][MCONTROL2_6_EXECUTE] && priv_lvl_match_en_if[idx] && !ctrl_fsm_i.debug_mode && !ptr_in_if_i &&
                                       if_addr_match[idx];

        ///////////////////////////////////////
        // Load/Store address match (EX)
        ///////////////////////////////////////

        // As for instruction address match, the load/store address match happens before the a bus transaction is visible on the OBI bus.
        // For split misaligned transfers, each transfer is checked separately. This means that half a store may be visible externally even if
        // the second part matches tdata2 and debug is entered. For loads the RF write will not happen until the last part finished anyway, so no state update
        // will happen regardless of which transaction matches.
        // The BE of the transaction is used to determine which bytes of a word is being accessed.

        // Check if any accessed byte matches the lower two bits of tdata2
        always_comb begin
          for (int b=0; b<4; b++) begin
            if (lsu_be_ex_i[b] && (2'(b) == tdata2_rdata[idx][1:0])) begin
              lsu_byte_addr_match[idx][b] = 1'b1;
            end else begin
              lsu_byte_addr_match[idx][b] = 1'b0;
            end
          end
        end

        // Check address matches for (==), (>=) and (<)
        // For ==, check that we match the 32-bit aligned word and that any of the accessed bytes matches tdata2[1:0]
        // For >=, check that the highest accessed address is greater than or equal to tdata2. If this fails, no bytes within the access are >= tdata2
        // For <, check that the lowest accessed address is less than tdata2. If this fails, no bytes within the access are < tdata2.
        assign lsu_addr_match[idx] = (tdata1_rdata[idx][MCONTROL2_6_MATCH_HIGH:MCONTROL2_6_MATCH_LOW] == 4'h0) ? ((lsu_addr_ex_i[31:2] == tdata2_rdata[idx][31:2]) && (|lsu_byte_addr_match[idx])) :
                                     (tdata1_rdata[idx][MCONTROL2_6_MATCH_HIGH:MCONTROL2_6_MATCH_LOW] == 4'h2) ? (lsu_addr_high >= tdata2_rdata[idx]) :
                                                                                                             (lsu_addr_low  <  tdata2_rdata[idx]) ;

        // Check if matching is enabled for the current privilege level from EX
        assign priv_lvl_match_en_ex[idx] = (tdata1_rdata[idx][MCONTROL2_6_M] && (priv_lvl_ex_i == PRIV_LVL_M)) ||
                                           (tdata1_rdata[idx][MCONTROL2_6_U] && (priv_lvl_ex_i == PRIV_LVL_U));

        // Enable LSU address matching
        assign lsu_addr_match_en[idx] = lsu_valid_ex_i && ((tdata1_rdata[idx][MCONTROL2_6_LOAD] && !lsu_we_ex_i) || (tdata1_rdata[idx][MCONTROL2_6_STORE] && lsu_we_ex_i));

        // Signal trigger match for LSU address
        assign trigger_match_ex[idx] = ((tdata1_rdata[idx][TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL)   ||
                                        (tdata1_rdata[idx][TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_MCONTROL6)) &&
                                        priv_lvl_match_en_ex[idx] &&  lsu_addr_match_en[idx] && lsu_addr_match[idx] && !ctrl_fsm_i.debug_mode;

        /////////////////////////////
        // Exception trigger
        /////////////////////////////

        always_comb begin
          exception_match[idx] = 32'd0;
          for (int i=0; i<32; i++) begin
            exception_match[idx][i] = tdata2_rdata[idx][i] && ctrl_fsm_i.exception_in_wb && (ctrl_fsm_i.exception_cause_wb == 11'(i));
          end
        end

        assign priv_lvl_match_en_wb[idx] = (tdata1_rdata[idx][ETRIGGER_M] && (priv_lvl_wb_i == PRIV_LVL_M)) ||
                                           (tdata1_rdata[idx][ETRIGGER_U] && (priv_lvl_wb_i == PRIV_LVL_U));

        assign etrigger_wb[idx] = (tdata1_rdata[idx][TDATA1_TTYPE_HIGH:TDATA1_TTYPE_LOW] == TTYPE_ETRIGGER) && priv_lvl_match_en_wb[idx] &&
                                  (|exception_match[idx]) && !ctrl_fsm_i.debug_mode;



        cv32e40s_csr
        #(
          .LIB        (LIB),
          .WIDTH      (32),
          .SHADOWCOPY (1'b0),
          .RESETVALUE (TDATA1_RST_VAL)
        )
        tdata1_csr_i
        (
          .clk                ( clk                   ),
          .rst_n              ( rst_n                 ),
          .scan_cg_en_i       ( scan_cg_en_i          ),
          .wr_data_i          ( tdata1_n[idx]         ),
          .wr_en_i            ( tdata1_we_int[idx]    ),
          .rd_data_o          ( tdata1_q[idx]         ),
          .rd_error_o         ( tdata1_rd_error[idx]  )
        );

        cv32e40s_csr
        #(
          .LIB        (LIB),
          .WIDTH      (32),
          .SHADOWCOPY (1'b0),
          .RESETVALUE (32'd0)
        )
        tdata2_csr_i
        (
          .clk                ( clk                   ),
          .rst_n              ( rst_n                 ),
          .scan_cg_en_i       ( scan_cg_en_i          ),
          .wr_data_i          ( tdata2_n              ),
          .wr_en_i            ( tdata2_we_int[idx]    ),
          .rd_data_o          ( tdata2_q[idx]         ),
          .rd_error_o         ( tdata2_rd_error[idx]  )
        );

        // Set write enables
        assign tdata1_we_int[idx] = (tdata1_we_i && (tselect_rdata_o == idx)) || tdata1_we_hit[idx];
        assign tdata2_we_int[idx] = tdata2_we_i && (tselect_rdata_o == idx);

        // Assign read data
        assign tdata1_rdata[idx] = tdata1_q[idx];
        assign tdata2_rdata[idx] = tdata2_q[idx];
      end // for

      // CSR instance for tselect
      cv32e40s_csr
      #(
        .LIB        (LIB),
        .WIDTH      (32),
        .SHADOWCOPY (1'b0),
        .RESETVALUE (32'd0)
      )
      tselect_csr_i
      (
        .clk                ( clk                   ),
        .rst_n              ( rst_n                 ),
        .scan_cg_en_i       ( scan_cg_en_i          ),
        .wr_data_i          ( tselect_n             ),
        .wr_en_i            ( tselect_we_i          ),
        .rd_data_o          ( tselect_q             ),
        .rd_error_o         ( tselect_rd_error      )
      );

      // Assign CSR read data outputs
      always_comb begin
        tdata1_rdata_o = tdata1_rdata[0];
        tdata2_rdata_o = tdata2_rdata[0];

        // Iterate through triggers and set tdata1/tdata2 rdata for the currently selected trigger
        for (int unsigned i=0; i<DBG_NUM_TRIGGERS; i++) begin
          if(tselect_rdata_o == i) begin
            tdata1_rdata_o = tdata1_rdata[i];
            tdata2_rdata_o = tdata2_rdata[i];
          end
        end
      end

      // RVFI only
      // assign _we_r and wdata_n_r values
      always_comb begin
        tdata1_we_r = tdata1_we_i || tselect_we_i;
        tdata2_we_r = tdata2_we_i || tselect_we_i;

        tdata1_n_r = tdata1_n[0];
        tdata2_n_r = tdata2_n;

        // Iterate over all triggers and pick tdata1_n_r and tdata1_we_r for the
        // currently selected trigger.
        for (int unsigned i=0; i<DBG_NUM_TRIGGERS; i++) begin
          if(tselect_rdata_o == i) begin
            tdata1_n_r = tdata1_n[i];
            // Using tdata1_we_int to include HW writes to mcontrol6
            tdata1_we_r = tdata1_we_int[i] || tselect_we_i;
          end
        end

        // Make sure to update SW visible trigger CSRs on RVFI
        // when tselect is written
        if (tselect_we_i) begin
          for (int unsigned i=0; i<DBG_NUM_TRIGGERS; i++) begin
            if(tselect_n == i) begin
              tdata1_n_r = tdata1_rdata[i];
              tdata2_n_r = tdata2_rdata[i];
            end
          end
        end
      end


      assign tselect_rdata_o  = tselect_q;
      assign tinfo_rdata_o    = 32'h01008064; // Supported types 0x2, 0x5, 0x6 and 0xF, tinfo.version=1

      // Set trigger match for IF
      assign trigger_match_if_o = {{(32-DBG_NUM_TRIGGERS){1'b0}}, trigger_match_if};

      // Set trigger match for EX
      assign trigger_match_ex_o = {{(32-DBG_NUM_TRIGGERS){1'b0}}, trigger_match_ex};

      // Set trigger match for WB
      assign etrigger_wb_o = |etrigger_wb;

      assign unused_signals = tinfo_we_i | (|tinfo_n) | (|tdata1_rd_error) | (|tdata2_rd_error) | tselect_rd_error |
                              (|tdata1_n_r) | (|tdata2_n_r) | tdata1_we_r | tdata2_we_r;

    end else begin : gen_no_triggers
      // Tie off outputs
      assign tdata1_rdata_o = '0;
      assign tdata2_rdata_o = '0;
      assign tselect_rdata_o = '0;
      assign tinfo_rdata_o = '0;
      assign trigger_match_if_o = '0;
      assign trigger_match_ex_o = '0;
      assign etrigger_wb_o = '0;
      assign tdata1_n = '0;
      assign tdata2_n = '0;
      assign tselect_n = '0;
      assign tinfo_n = '0;
      assign tdata1_n_r = '0;
      assign tdata2_n_r = '0;
      assign tdata1_we_r = 1'b0;
      assign tdata2_we_r = 1'b0;

      assign unused_signals = (|tdata1_n) | (|tdata2_n) | (|tselect_n) | (|tinfo_n) |
                              (|csr_wdata_i) | tdata1_we_i | tdata2_we_i | tselect_we_i | tinfo_we_i |
                              (|tdata1_n_r) | (|tdata2_n_r) | tdata1_we_r | tdata2_we_r;
    end
  endgenerate
endmodule