Subversion Repositories nysa_sata

//sata_phy_layer.v

/*

Distributed under the MIT license.

Copyright (c) 2011 Dave McCoy (dave.mccoy@cospandesign.com)

Permission is hereby granted, free of charge, to any person obtaining a copy of

this software and associated documentation files (the "Software"), to deal in

the Software without restriction, including without limitation the rights to

use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

of the Software, and to permit persons to whom the Software is furnished to do

so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.

*/

`include "sata_defines.v"

module sata_phy_layer (

input               rst,            //reset

input               clk,

input               platform_ready,   //the underlying physical platform is

output              linkup,           //link is finished

output  [31:0]      tx_dout,

output              tx_isk,

output              tx_comm_reset,

output              tx_comm_wake,

output              tx_elec_idle,

input   [31:0]      rx_din,

input   [3:0]       rx_isk,

input               rx_elec_idle,

input               rx_byte_is_aligned,

input               comm_init_detect,

input               comm_wake_detect,

output              phy_ready,

output      [3:0]   lax_state

);

//Parameters

parameter           NOT_READY         = 4'h0;

parameter           SEND_FIRST_ALIGN  = 4'h1;

parameter           SEND_SECOND_ALIGN = 4'h2;

parameter           READY             = 4'h3;

//Registers/Wires

reg         [3:0]   state;

reg         [7:0]   align_count;

//OOB Control

wire        [31:0]  oob_tx_dout;

wire                oob_tx_isk;

//Phy Control

wire        [31:0]  phy_tx_dout;

wire                phy_tx_isk;

wire                align_detected;

//Submodules

oob_controller oob (

  .rst                (rst),

  .clk                (clk),

  //OOB controller

  .platform_ready     (platform_ready),

  .linkup             (linkup),

  //Platform Control

  .tx_dout            (oob_tx_dout),

  .tx_isk             (oob_tx_isk),

  .tx_comm_reset      (tx_comm_reset),

  .tx_comm_wake       (tx_comm_wake),

  .tx_set_elec_idle   (tx_elec_idle),

  .rx_din             (rx_din),

  .rx_isk             (rx_isk),

  .comm_init_detect   (comm_init_detect),

  .comm_wake_detect   (comm_wake_detect),

  .rx_byte_is_aligned (rx_byte_is_aligned),

  .rx_is_elec_idle    (rx_elec_idle),

  .lax_state          (lax_state)

);

//Asynchronous Logic

assign              tx_dout         = !linkup ? oob_tx_dout : phy_tx_dout;

assign              tx_isk          = !linkup ? oob_tx_isk  : phy_tx_isk;

assign              phy_tx_dout     =  `PRIM_ALIGN;

assign              phy_tx_isk      =  1;

assign              align_detected  = ((rx_isk > 0) && (rx_din == `PRIM_ALIGN) && rx_byte_is_aligned);

//assign              phy_ready       = ((state == READY) && (!align_detected));

assign              phy_ready       = (state == READY);

//Synchronous Logic

always @ (posedge clk) begin

  if (rst) begin

    state             <=  NOT_READY;

    align_count       <=  0;

  end

  else begin

    if (state == READY) begin

      align_count       <=  align_count + 1;

    end

    case (state)

      NOT_READY:  begin

        align_count   <=  0;

        if (linkup) begin

`ifdef VERBOSE

          $display ("sata_phy_layer: linkup! send aligns");

`endif

          state       <=  SEND_FIRST_ALIGN;

        end

      end

      SEND_FIRST_ALIGN: begin

        state         <=  SEND_SECOND_ALIGN;

      end

      SEND_SECOND_ALIGN: begin

        state         <=  READY;

      end

      READY:      begin

        if (align_count ==  255) begin

          state       <=  SEND_FIRST_ALIGN;

`ifdef VERBOSE

          $display ("sata_phy_layer: linkup! send alignment dwords");

`else

          $display ("sata_phy_layer: .");

`endif

//Send an align primitive

        end

      end

      default:    begin

      end

    endcase

  end

end

endmodule