// ***************************************************************************
// ***************************************************************************
// Copyright 2011(c) Analog Devices, Inc.
// 
// 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 Analog Devices, Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//     - The use of this software may or may not infringe the patent rights
//       of one or more patent holders.  This license does not release you
//       from the requirement that you obtain separate licenses from these
//       patent holders to use this software.
//     - Use of the software either in source or binary form, must be run
//       on or directly connected to an Analog Devices Inc. component.
//    
// THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED.
//
// IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY
// RIGHTS, 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.
// ***************************************************************************
// ***************************************************************************
// ***************************************************************************
// ***************************************************************************

`timescale 1ns/100ps

module up_clkgen (

  // mmcm reset

  mmcm_rst,

  // drp interface

  drp_clk,
  drp_rst,
  drp_sel,
  drp_wr,
  drp_addr,
  drp_wdata,
  drp_rdata,
  drp_ready,
  drp_locked,

  // bus interface

  up_rstn,
  up_clk,
  up_wreq,
  up_waddr,
  up_wdata,
  up_wack,
  up_rreq,
  up_raddr,
  up_rdata,
  up_rack);

  // parameters

  localparam  PCORE_VERSION = 32'h00040063;
  parameter   PCORE_ID = 0;

  // mmcm reset

  output          mmcm_rst;

  // drp interface

  input           drp_clk;
  output          drp_rst;
  output          drp_sel;
  output          drp_wr;
  output  [11:0]  drp_addr;
  output  [15:0]  drp_wdata;
  input   [15:0]  drp_rdata;
  input           drp_ready;
  input           drp_locked;

  // bus interface

  input           up_rstn;
  input           up_clk;
  input           up_wreq;
  input   [13:0]  up_waddr;
  input   [31:0]  up_wdata;
  output          up_wack;
  input           up_rreq;
  input   [13:0]  up_raddr;
  output  [31:0]  up_rdata;
  output          up_rack;


  // internal registers

  reg             up_wack = 'd0;
  reg     [31:0]  up_scratch = 'd0;
  reg             up_mmcm_resetn = 'd0;
  reg             up_resetn = 'd0;
  reg             up_drp_sel_t = 'd0;
  reg             up_drp_rwn = 'd0;
  reg     [11:0]  up_drp_addr = 'd0;
  reg     [15:0]  up_drp_wdata = 'd0;
  reg             up_rack = 'd0;
  reg     [31:0]  up_rdata = 'd0;

  // internal signals

  wire            up_wreq_s;
  wire            up_rreq_s;
  wire            up_preset_s;
  wire            up_mmcm_preset_s;
  wire    [15:0]  up_drp_rdata_s;
  wire            up_drp_status_s;
  wire            up_drp_locked_s;

  // decode block select

  assign up_wreq_s = (up_waddr[13:8] == 6'h00) ? up_wreq : 1'b0;
  assign up_rreq_s = (up_raddr[13:8] == 6'h00) ? up_rreq : 1'b0;
  assign up_preset_s = ~up_resetn;
  assign up_mmcm_preset_s = ~up_mmcm_resetn;

  // processor write interface

  always @(negedge up_rstn or posedge up_clk) begin
    if (up_rstn == 0) begin
      up_wack <= 'd0;
      up_scratch <= 'd0;
      up_mmcm_resetn <= 'd0;
      up_resetn <= 'd0;
      up_drp_sel_t <= 'd0;
      up_drp_rwn <= 'd0;
      up_drp_addr <= 'd0;
      up_drp_wdata <= 'd0;
    end else begin
      up_wack <= up_wreq_s;
      if ((up_wreq_s == 1'b1) && (up_waddr[7:0] == 8'h02)) begin
        up_scratch <= up_wdata;
      end
      if ((up_wreq_s == 1'b1) && (up_waddr[7:0] == 8'h10)) begin
        up_mmcm_resetn <= up_wdata[1];
        up_resetn <= up_wdata[0];
      end
      if ((up_wreq_s == 1'b1) && (up_waddr[7:0] == 8'h1c)) begin
        up_drp_sel_t <= ~up_drp_sel_t;
        up_drp_rwn <= up_wdata[28];
        up_drp_addr <= up_wdata[27:16];
        up_drp_wdata <= up_wdata[15:0];
      end
    end
  end

  // processor read interface

  always @(negedge up_rstn or posedge up_clk) begin
    if (up_rstn == 0) begin
      up_rack <= 'd0;
      up_rdata <= 'd0;
    end else begin
      up_rack <= up_rreq_s;
      if (up_rreq_s == 1'b1) begin
        case (up_waddr[7:0])
          8'h00: up_rdata <= PCORE_VERSION;
          8'h01: up_rdata <= PCORE_ID;
          8'h02: up_rdata <= up_scratch;
          8'h10: up_rdata <= {30'd0, up_mmcm_resetn, up_resetn};
          8'h17: up_rdata <= {31'd0, up_drp_locked_s};
          8'h1c: up_rdata <= {3'd0, up_drp_rwn, up_drp_addr, up_drp_wdata};
          8'h1d: up_rdata <= {14'd0, up_drp_locked_s, up_drp_status_s, up_drp_rdata_s};
          default: up_rdata <= 0;
        endcase
      end else begin
        up_rdata <= 32'd0;
      end
    end
  end

  // resets

  ad_rst i_mmcm_rst_reg   (.preset(up_mmcm_preset_s), .clk(drp_clk),    .rst(mmcm_rst));
  ad_rst i_drp_rst_reg    (.preset(up_preset_s),      .clk(drp_clk),    .rst(drp_rst));

  // drp control & status

  up_drp_cntrl i_drp_cntrl (
    .drp_clk (drp_clk),
    .drp_rst (drp_rst),
    .drp_sel (drp_sel),
    .drp_wr (drp_wr),
    .drp_addr (drp_addr),
    .drp_wdata (drp_wdata),
    .drp_rdata (drp_rdata),
    .drp_ready (drp_ready),
    .drp_locked (drp_locked),
    .up_rstn (up_rstn),
    .up_clk (up_clk),
    .up_drp_sel_t (up_drp_sel_t),
    .up_drp_rwn (up_drp_rwn),
    .up_drp_addr (up_drp_addr),
    .up_drp_wdata (up_drp_wdata),
    .up_drp_rdata (up_drp_rdata_s),
    .up_drp_status (up_drp_status_s),
    .up_drp_locked (up_drp_locked_s));

endmodule

// ***************************************************************************
// ***************************************************************************