//======================================================================
//
// keywrap_mkmif.v
// ---------------
// Wrapper for the mkmif_core. This allow us to simplify the
// integration of the mkmif in keywrap_core.
//
//
// Author: Joachim Strombergson
// Copyright (c) 2018, NORDUnet A/S
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// - Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the distribution.
//
// - Neither the name of the NORDUnet nor the names of its contributors may
//   be used to endorse or promote products derived from this software
//   without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//======================================================================

module keywrap_mkmif (
                      input wire            clk,
                      input wire            reset_n,

                      output wire           mkm_spi_sclk,
                      output wire           mkm_spi_cs_n,
                      input wire            mkm_spi_do,
                      output wire           mkm_spi_di,

                      input wire            init,
                      input wire            read,
                      input wire            write,
                      input wire            key_status,
                      output wire           ready,

                      input wire [31 : 0]   wr_status,
                      output wire [31 : 0]  rd_status,
                      input wire [255 : 0]  wr_key,
                      output wire [255 : 0] rd_key
                     );


  //----------------------------------------------------------------
  // Paramenters and local defines.
  //----------------------------------------------------------------
  localparam CTRL_IDLE             = 4'h0;
  localparam CTRL_WAIT             = 4'h1;
  localparam CTRL_INIT             = 4'h2;
  localparam CTRL_READ             = 4'h3;
  localparam CTRL_READ_STATUS_WAIT = 4'h4;
  localparam CTRL_READ_KEY         = 4'h5;
  localparam CTRL_READ_KEY_WAIT    = 4'h6;
  localparam CTRL_WRITE            = 4'h8;
  localparam CTRL_WRITE_KEY        = 4'h9;
  localparam CTRL_WRITE_KEY_WAIT   = 4'ha;

  // Addresses for storage in the mkm
  localparam MKM_STATUS_WORD     = 16'h00;
  localparam MKM_KEY_BASE_WORD   = 16'h04;

  localparam DEFAULT_SCLK_DIV    = 16'h0020;


  //----------------------------------------------------------------
  // Registers and memories including control signals.
  //----------------------------------------------------------------
  reg [31 : 0] key_reg [0 : 7];
  reg          key_we;

  reg [2 : 0]  key_word_ctr_reg;
  reg [2 : 0]  key_word_ctr_new;
  reg          key_word_ctr_we;
  reg          key_word_ctr_rst;
  reg          key_word_ctr_inc;

  reg [15 : 0] mkm_addr_reg;
  reg [15 : 0] mkm_addr_new;
  reg          mkm_addr_we;

  reg [31 : 0] mkm_write_data_reg;
  reg [31 : 0] mkm_write_data_new;
  reg          mkm_write_data_we;

  reg [31 : 0] status_reg;
  reg [31 : 0] status_new;
  reg          status_we;

  reg          ready_reg;
  reg          ready_new;
  reg          ready_we;

  reg [3 : 0]  keywrap_mkmif_ctrl_reg;
  reg [3 : 0]  keywrap_mkmif_ctrl_new;
  reg          keywrap_mkmif_ctrl_we;

  reg init_op_reg;
  reg read_op_reg;
  reg write_op_reg;


  //----------------------------------------------------------------
  // Wires.
  //----------------------------------------------------------------
  reg           mkm_init_op;
  reg           mkm_read_op;
  reg           mkm_write_op;
  wire          mkm_ready;
  wire          mkm_valid;
  reg [15 : 0]  mkm_addr;
  reg [31 : 0]  mkm_write_data;
  wire [31 : 0] mkm_read_data;


  //----------------------------------------------------------------
  // Instantiations.
  //----------------------------------------------------------------
  mkmif_core mkm(
                 .clk(clk),
                 .reset_n(reset_n),

                 .spi_sclk(mkm_spi_sclk),
                 .spi_cs_n(mkm_spi_cs_n),
                 .spi_do(mkm_spi_do),
                 .spi_di(mkm_spi_di),

                 .init_op(init_op_reg),
                 .read_op(read_op_reh),
                 .write_op(write_op_reg),

                 .ready(mkm_ready),
                 .valid(mkm_valid),

                 .sclk_div(DEFAULT_SCLK_DIV),
                 .addr(mkm_addr_reg),
                 .write_data(mkm_write_data_reg),
                 .read_data(mkm_read_data)
                );


  //----------------------------------------------------------------
  // Assignments for ports.
  //----------------------------------------------------------------
  assign ready = ready_reg;

  assign rd_status = status_reg;

  assign rd_key = {key_reg[7], key_reg[6], key_reg[5], key_reg[4],
                   key_reg[3], key_reg[2], key_reg[1], key_reg[0]};


  //----------------------------------------------------------------
  // reg_update
  //----------------------------------------------------------------
  always @ (posedge clk or negedge reset_n)
    begin: reg_update
      integer i;

      if (!reset_n)
        begin
          for (i = 0 ; i < 8 ; i = i + 1)
            key_reg[i] <= 32'h0;

          ready_reg              <= 1'h1;
          status_reg             <= 32'h0;
          mkm_addr_reg           <= 16'h0;
          mkm_write_data_reg     <= 32'h0;
          key_word_ctr_reg       <= 3'h0;
          init_op_reg            <= 1'h0;
          read_op_reg            <= 1'h0;
          write_op_reg           <= 1'h0;
          keywrap_mkmif_ctrl_reg <= CTRL_IDLE;
       end

      else
        begin
          init_op_reg <= mkm_init_op;
          read_op_reg <= mkm_read_op;
          write_op_reg <= mkm_write_op;

          if (ready_we)
            ready_reg <= ready_new;

          if (mkm_addr_we)
            mkm_addr_reg <= mkm_addr_new;

          if (mkm_write_data_we)
            mkm_write_data_reg <= mkm_write_data_new;

          if (key_we)
            key_reg[key_word_ctr_reg] <= mkm_read_data;

          if (status_we)
            status_reg <= mkm_read_data;

          if (key_word_ctr_we)
            key_word_ctr_reg <= key_word_ctr_new;

          if (keywrap_mkmif_ctrl_we)
            keywrap_mkmif_ctrl_reg <= keywrap_mkmif_ctrl_new;
        end
    end // reg_update


  //----------------------------------------------------------------
  // key_word_ctr
  //----------------------------------------------------------------
  always @*
    begin : key_word_ctr
      key_word_ctr_new = 3'h0;
      key_word_ctr_we  = 1'h0;

      if (key_word_ctr_rst)
        begin
          key_word_ctr_new = 3'h0;
          key_word_ctr_we  = 1'h1;
        end

      if (key_word_ctr_inc)
        begin
          key_word_ctr_new = key_word_ctr_reg + 1'h1;
          key_word_ctr_we  = 1'h1;
        end

    end


  //----------------------------------------------------------------
  // keywrap_mkmif_ctrl
  //----------------------------------------------------------------
  always @*
    begin : keywrap_mkmif_ctrl
      ready_new              = 1'h0;
      ready_we               = 1'h0;
      key_we                 = 1'h0;
      key_word_ctr_rst       = 1'h0;
      key_word_ctr_inc       = 1'h0;
      status_we              = 1'h0;
      mkm_init_op            = 1'h0;
      mkm_read_op            = 1'h0;
      mkm_write_op           = 1'h0;
      mkm_addr_new           = 16'h0;
      mkm_addr_we            = 1'h0;
      mkm_write_data_new     = 32'h0;
      mkm_write_data_we      = 1'h0;
      keywrap_mkmif_ctrl_new = CTRL_IDLE;
      keywrap_mkmif_ctrl_we  = 1'h0;

      case (keywrap_mkmif_ctrl_reg)
        CTRL_IDLE:
          begin
            if (init)
              begin
                mkm_init_op            = 1'h1;
                ready_new              = 1'h0;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_INIT;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end

            if (read)
              begin
                ready_new              = 1'h0;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_READ;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end

            if (write)
              begin
                ready_new              = 1'h0;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_WRITE;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_INIT:
          begin
            keywrap_mkmif_ctrl_new = CTRL_WAIT;
            keywrap_mkmif_ctrl_we  = 1'h1;
          end


        CTRL_READ:
          begin
            if (key_status)
              begin
                key_word_ctr_rst       = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_READ_KEY;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
            else
              begin
                mkm_read_op            = 1'h1;
                mkm_addr_new           = MKM_STATUS_WORD;
                mkm_addr_we            = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_READ_STATUS_WAIT;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_WAIT:
          begin
            if (mkm_ready)
              begin
                ready_new              = 1'h1;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_IDLE;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_READ_STATUS_WAIT:
          begin
            ready_new              = 1'h1;
            ready_we               = 1'h1;
            keywrap_mkmif_ctrl_new = CTRL_IDLE;
            keywrap_mkmif_ctrl_we  = 1'h1;
            if (mkm_ready)
              begin
                status_we              = 1'h1;
                ready_new              = 1'h1;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_IDLE;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_READ_KEY:
          begin
            if (key_word_ctr_reg < 8)
              begin
                mkm_read_op            = 1'h1;
                mkm_addr_new           = MKM_KEY_BASE_WORD + {key_word_ctr_reg, 2'h0};
                mkm_addr_we            = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_READ_KEY_WAIT;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
            else
              begin
                ready_new              = 1'h1;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_IDLE;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_READ_KEY_WAIT:
          begin
            if (mkm_ready)
              begin
                key_we                 = 1'h1;
                key_word_ctr_inc       = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_READ_KEY;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_WRITE:
          begin
            if (key_status)
              begin
                key_word_ctr_rst       = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_WRITE_KEY;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
            else
              begin
                mkm_write_op           = 1'h1;
                mkm_addr_new           = MKM_STATUS_WORD;
                mkm_addr_we            = 1'h1;
                mkm_write_data_new     = wr_status;
                mkm_write_data_we      = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_WAIT;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_WRITE_KEY:
          begin
            if (key_word_ctr_reg < 8)
              begin
                mkm_write_op           = 1'h1;
                mkm_addr_new           = MKM_KEY_BASE_WORD + {key_word_ctr_reg, 2'h0};
                mkm_addr_we            = 1'h1;
                mkm_write_data_new     = wr_key[key_word_ctr_reg * 32 +: 32];
                mkm_write_data_we      = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_WRITE_KEY_WAIT;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
            else
              begin
                ready_new              = 1'h1;
                ready_we               = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_IDLE;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        CTRL_WRITE_KEY_WAIT:
          begin
            if (mkm_ready)
              begin
                key_word_ctr_inc       = 1'h1;
                keywrap_mkmif_ctrl_new = CTRL_WRITE_KEY;
                keywrap_mkmif_ctrl_we  = 1'h1;
              end
          end


        default:
          begin
          end
      endcase // case (keywrap_mkmif_ctrl_reg)
    end // keywrap_mkmif_ctrl

endmodule // keywrap_mkmif

//======================================================================
// EOF keywrap_mkmif.v
//======================================================================