// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0
//
// Register Top module auto-generated by `reggen`


module gpio_reg_top (
  input  logic        clk_i,
  input  logic        rst_ni,

  // To HW
  output gpio_reg_pkg::gpio_reg2hw_t reg2hw, // Write
  input  gpio_reg_pkg::gpio_hw2reg_t hw2reg, // Read

  input  logic        reg_we,
  input  logic        reg_re,
  input  logic [31:0] reg_wdata,
  input  logic [ 3:0] reg_be,
  input  logic [31:0] reg_addr,
  output logic [31:0] reg_rdata
);

  import gpio_reg_pkg::* ;

  localparam int AW = 4;
  localparam int DW = 32;
  localparam int DBW = DW/8;    // Byte Width

  logic reg_error;
  logic addrmiss, wr_err;

  logic [DW-1:0] reg_rdata_next;

  assign reg_rdata = reg_rdata_next;
  assign reg_error = wr_err;

  // Define SW related signals
  // Format: <reg>_<field>_{wd|we|qs}
  //        or <reg>_{wd|we|qs} if field == 1 or 0
  logic mode_we;
  logic [15:0] mode_qs;
  logic [15:0] mode_wd;
  logic intr_we;
  logic [15:0] intr_gpio_int_qs;
  logic [15:0] intr_gpio_int_wd;
  logic [7:0] intr_gpio_pending_qs;
  logic [7:0] intr_gpio_pending_wd;
  logic data_we;
  logic [7:0] data_qs;
  logic [7:0] data_wd;
  logic filter_we;
  logic [7:0] filter_qs;
  logic [7:0] filter_wd;

  // Register instances
  // R[mode]: V(False)

  prim_subreg #(
    .DW      (16),
    .SWACCESS("RW"),
    .RESVAL  (16'h0)
  ) u_mode (
    .clk_i   (clk_i),
    .rst_ni  (rst_ni),

    // from register interface
    .we     (mode_we),
    .wd     (mode_wd),

    // from internal hardware
    .de     (1'b0),
    .d      ('0),

    // to internal hardware
    .qe     (),
    .q      (reg2hw.mode.q),

    // to register interface (read)
    .qs     (mode_qs)
  );


  // R[intr]: V(False)

  //   F[gpio_int]: 15:0
  prim_subreg #(
    .DW      (16),
    .SWACCESS("RW"),
    .RESVAL  (16'h0)
  ) u_intr_gpio_int (
    .clk_i   (clk_i),
    .rst_ni  (rst_ni),

    // from register interface
    .we     (intr_we),
    .wd     (intr_gpio_int_wd),

    // from internal hardware
    .de     (hw2reg.intr.gpio_int.de),
    .d      (hw2reg.intr.gpio_int.d),

    // to internal hardware
    .qe     (),
    .q      (reg2hw.intr.gpio_int.q),

    // to register interface (read)
    .qs     (intr_gpio_int_qs)
  );


  //   F[gpio_pending]: 23:16
  prim_subreg #(
    .DW      (8),
    .SWACCESS("W1C"),
    .RESVAL  (8'h0)
  ) u_intr_gpio_pending (
    .clk_i   (clk_i),
    .rst_ni  (rst_ni),

    // from register interface
    .we     (intr_we),
    .wd     (intr_gpio_pending_wd),

    // from internal hardware
    .de     (hw2reg.intr.gpio_pending.de),
    .d      (hw2reg.intr.gpio_pending.d),

    // to internal hardware
    .qe     (),
    .q      (reg2hw.intr.gpio_pending.q),

    // to register interface (read)
    .qs     (intr_gpio_pending_qs)
  );


  // R[data]: V(False)

  prim_subreg #(
    .DW      (8),
    .SWACCESS("RW"),
    .RESVAL  (8'h0)
  ) u_data (
    .clk_i   (clk_i),
    .rst_ni  (rst_ni),

    // from register interface
    .we     (data_we),
    .wd     (data_wd),

    // from internal hardware
    .de     (hw2reg.data.de),
    .d      (hw2reg.data.d),

    // to internal hardware
    .qe     (),
    .q      (reg2hw.data.q),

    // to register interface (read)
    .qs     (data_qs)
  );


  // R[filter]: V(False)

  prim_subreg #(
    .DW      (8),
    .SWACCESS("RW"),
    .RESVAL  (8'h0)
  ) u_filter (
    .clk_i   (clk_i),
    .rst_ni  (rst_ni),

    // from register interface
    .we     (filter_we),
    .wd     (filter_wd),

    // from internal hardware
    .de     (1'b0),
    .d      ('0),

    // to internal hardware
    .qe     (),
    .q      (reg2hw.filter.q),

    // to register interface (read)
    .qs     (filter_qs)
  );


  logic [3:0] addr_hit;
  always_comb begin
    addr_hit = '0;
    addr_hit[0] = (reg_addr == GPIO_MODE_OFFSET);
    addr_hit[1] = (reg_addr == GPIO_INTR_OFFSET);
    addr_hit[2] = (reg_addr == GPIO_DATA_OFFSET);
    addr_hit[3] = (reg_addr == GPIO_FILTER_OFFSET);
  end

  assign addrmiss = (reg_re || reg_we) ? ~|addr_hit : 1'b0 ;

  // Check sub-word write is permitted
  always_comb begin
    wr_err = (reg_we &
              ((addr_hit[0] & (|(GPIO_PERMIT[0] & ~reg_be))) |
               (addr_hit[1] & (|(GPIO_PERMIT[1] & ~reg_be))) |
               (addr_hit[2] & (|(GPIO_PERMIT[2] & ~reg_be))) |
               (addr_hit[3] & (|(GPIO_PERMIT[3] & ~reg_be)))));
  end

  assign mode_we = addr_hit[0] & reg_we & !reg_error;

  assign mode_wd = reg_wdata[15:0];
  assign intr_we = addr_hit[1] & reg_we & !reg_error;

  assign intr_gpio_int_wd = reg_wdata[15:0];

  assign intr_gpio_pending_wd = reg_wdata[23:16];
  assign data_we = addr_hit[2] & reg_we & !reg_error;

  assign data_wd = reg_wdata[7:0];
  assign filter_we = addr_hit[3] & reg_we & !reg_error;

  assign filter_wd = reg_wdata[7:0];

  // Read data return
  always_comb begin
    reg_rdata_next = '0;
    unique case (1'b1)
      addr_hit[0]: begin
        reg_rdata_next[15:0] = mode_qs;
      end

      addr_hit[1]: begin
        reg_rdata_next[15:0] = intr_gpio_int_qs;
        reg_rdata_next[23:16] = intr_gpio_pending_qs;
      end

      addr_hit[2]: begin
        reg_rdata_next[7:0] = data_qs;
      end

      addr_hit[3]: begin
        reg_rdata_next[7:0] = filter_qs;
      end

      default: begin
        reg_rdata_next = '1;
      end
    endcase
  end

  // Unused signal tieoff

  // wdata / byte enable are not always fully used
  // add a blanket unused statement to handle lint waivers
  logic unused_wdata;
  logic unused_be;
  assign unused_wdata = ^reg_wdata;
  assign unused_be = ^reg_be;

endmodule