//======================================================================
//
// keywrap_core.v
// --------------
// Core that tries to implement AES KEY WRAP as specified in
// RFC 3394 and extended with padding in RFC 5649.
// Experimental core at the moment. Does Not Work.
// The maximum wrap object size is 64 kByte.
//
//
// 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_core (
                     input wire           clk,
                     input wire           reset_n,

                     input wire           encdec,
                     input wire           init,
                     output wire          ready,
                     input wire [255 : 0] key,
                     input wire           keylen,
                     input wire [13 : 0]  message_len,

                     input wire           api_we,
                     input wire [13 : 0]  api_addr,
                     input wire [31 : 0]  api_wr_data,
                     output wire [31 : 0] api_rd_data
                    );


  //----------------------------------------------------------------
  // Paramenters and local defines.
  //----------------------------------------------------------------
  localparam OUTER_LOOP_MAX = 6;


  localparam CTRL_IDLE  = 3'h0;
  localparam CTRL_INIT  = 3'h1;
  localparam CTRL_NEXT  = 3'h2;

  localparam RFC5649_A_IV = 32'ha65959a6;


  //----------------------------------------------------------------
  // Registers and memories including control signals.
  //----------------------------------------------------------------
  reg [63 : 0] a_reg;
  reg [63 : 0] a_new;
  reg          a_we;
  reg          a_init;

  reg          ready_reg;
  reg          ready_new;
  reg          ready_we;

  reg [12 : 0] block_ctr_reg;
  reg [12 : 0] block_ctr_new;
  reg          block_ctr_we;
  reg          block_ctr_inc;
  reg          block_ctr_rst;

  reg [2 : 0]  iteration_ctr_reg;
  reg [2 : 0]  iteration_ctr_new;
  reg          iteration_ctr_we;
  reg          iteration_ctr_inc;
  reg          iteration_ctr_dec;
  reg          iteration_ctr_set;
  reg          iteration_ctr_rst;

  reg [2 : 0]  keywrap_core_ctrl_reg;
  reg [2 : 0]  keywrap_core_ctrl_new;
  reg          keywrap_core_ctrl_we;


  //----------------------------------------------------------------
  // Wires.
  //----------------------------------------------------------------
  reg            aes_encdec;
  reg            aes_init;
  reg            aes_next;
  wire           aes_ready;
  wire [255 : 0] aes_key;
  wire           aes_keylen;
  reg  [127 : 0] aes_block;
  wire [127 : 0] aes_result;
  wire           aes_valid;

  reg            core_we;
  reg [12 : 0]   core_addr;
  reg [63 : 0]   core_wr_data;
  wire [63 : 0]  core_rd_data;


  //----------------------------------------------------------------
  // Instantiations.
  //----------------------------------------------------------------
  keywrap_mem mem(
                  .clk(clk),
                  .reset_n(reset_n),
                  .api_we(api_we),
                  .api_addr(api_addr),
                  .api_wr_data(api_wr_data),
                  .api_rd_data(api_rd_data),
                  .core_we(),
                  .core_addr(),
                  .core_wr_data(),
                  .core_rd_data()
                 );


  aes_core aes(
               .clk(clk),
               .reset_n(reset_n),
               .encdec(aes_encdec),
               .init(aes_init),
               .next(aes_next),
               .ready(aes_ready),
               .key(aes_key),
               .keylen(aes_keylen),
               .block(aes_block),
               .result(aes_result),
               .result_valid(aes_valid)
              );

  //----------------------------------------------------------------
  // Assignments for ports.
  //----------------------------------------------------------------


  //----------------------------------------------------------------
  // reg_update
  //----------------------------------------------------------------
  always @ (posedge clk or negedge reset_n)
    begin: reg_update
      if (!reset_n)
        begin
          keywrap_core_ctrl_reg <= CTRL_IDLE;

        end

      else
        begin

          if (keywrap_core_ctrl_we)
            keywrap_core_ctrl_reg <= keywrap_core_ctrl_new;
        end
    end // reg_update


  //----------------------------------------------------------------
  // block_ctr
  //----------------------------------------------------------------
  always @*
    begin : block_ctr
      block_ctr_new = 13'h0;
      block_ctr_we  = 1'h0;

      if (block_ctr_rst)
        begin
          block_ctr_new = 13'h0;
          block_ctr_we  = 1'h1;
        end

      if (block_ctr_inc)
        begin
          block_ctr_new = block_ctr_reg + 1'h1;
          block_ctr_we  = 1'h1;
        end
    end


  //----------------------------------------------------------------
  // iteration_ctr
  //----------------------------------------------------------------
  always @*
    begin : iteration_ctr
      iteration_ctr_new = 3'h0;
      iteration_ctr_we  = 1'h0;

      if (iteration_ctr_rst)
        begin
          iteration_ctr_new = 3'h0;
          iteration_ctr_we  = 1'h1;
        end

      if (iteration_ctr_set)
        begin
          iteration_ctr_new = 3'h5;
          iteration_ctr_we  = 1'h1;
        end

      if (iteration_ctr_dec)
        begin
          iteration_ctr_new = iteration_ctr_reg + 1'h1;
          iteration_ctr_we  = 1'h1;
        end

      if (iteration_ctr_inc)
        begin
          iteration_ctr_new = iteration_ctr_reg + 1'h1;
          iteration_ctr_we  = 1'h1;
        end

    end


  //----------------------------------------------------------------
  // keywrap_core_ctrl
  //----------------------------------------------------------------
  always @*
    begin : keywrap_core_ctrl
      aes_encdec        = 0;
      aes_init          = 0;
      aes_next          = 0;
      block_ctr_inc     = 0;
      block_ctr_rst     = 0;
      iteration_ctr_inc = 0;
      iteration_ctr_dec = 0;
      iteration_ctr_set = 0;
      iteration_ctr_rst = 0;

      case (keywrap_core_ctrl_reg)
        CTRL_IDLE:
          begin
          end

        default:
          begin

          end
      endcase // case (keywrap_core_ctrl_reg)
    end // keywrap_core_ctrl

endmodule // keywrap_core

//======================================================================
// EOF keywrap_core.v
//======================================================================