design/sys/iop/dmu/rtl/dmu_ilu_iil_crdtcnt.v

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// OpenSPARC T2 Processor File: dmu_ilu_iil_crdtcnt.v
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module dmu_ilu_iil_crdtcnt (
                                 clk,
                                 rst_l,
                                 cib2iil_pec_drain,
                                 k2y_rel_rcd,
                                 k2y_rel_enq,
                                 d2p_ibc_req,
                                 d2p_ibc_nhc,
                                 d2p_ibc_phc,
                                 d2p_ibc_pdc,
                                 p2d_ibc_ack,
                                 is_ihb_rcd,
                                 credit_type );


  // synopsys sync_set_reset "rst_l"

  // >>>>>>>>>>>>>>>>>>>>>>>>> Port Declarations <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

  //---------------------------------------------------------------------
  //  Clock and Reset Signals
  //---------------------------------------------------------------------
  input           clk;              // input clock
  input           rst_l;            // input reset

  //---------------------------------------------------------------------
  //   DMA MWr buffer release interface from TMU
  //---------------------------------------------------------------------
  input [8:0]     k2y_rel_rcd;     // release rcd
  input           k2y_rel_enq;     // 1 PCIE FC credit (16-byte data)

  //---------------------------------------------------------------------
  //   PCIE FC credits interface to TLU
  //---------------------------------------------------------------------
  output          d2p_ibc_req;       // request for ingress buffer credits
  input           p2d_ibc_ack;       // ack for ingress buffer credits
  output   [7:0]  d2p_ibc_nhc;       // PCIE FC NPH credits
  output   [7:0]  d2p_ibc_phc;       // PCIE FC PH credits
  output  [11:0]  d2p_ibc_pdc;       // PCIE FC PD credits

  //---------------------------------------------------------------------
  //   ILU internal module interface
  //---------------------------------------------------------------------
  input           cib2iil_pec_drain; // reset FC credits when it is asserted

  //---------------------------------------------------------------------
  //   IIL internal interface
  //---------------------------------------------------------------------
  input [1:0]     credit_type;
                                     // 2'b10 - NPH, 2'b01 - PH, 2'b00 - CPLH
  input           is_ihb_rcd;        // collect fc credit,           from *xfrfsm.v

  // >>>>>>>>>>>>>>>>>>>>>>>>> Data Type Declarations <<<<<<<<<<<<<<<<<<<<<<<<<

  // ~~~~~~~~~~~~~~~~~~~~~~~~~ REGISTER - FLOPS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  reg             d2p_ibc_req;
  reg      [7:0]  d2p_ibc_nhc;
  reg      [7:0]  d2p_ibc_phc;
  reg     [11:0]  d2p_ibc_pdc;

  reg             ibc_req;
  reg      [7:0]  ibc_nhc;
  reg      [7:0]  ibc_phc;
  reg     [11:0]  ibc_pdc;

  // ~~~~~~~~~~~~~~~~~~~~~~~~~ NETS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  wire            ibc_ack;           // sync-flop output

  wire            ld_inc_ibc_pdc;
  wire            ld_inc_ibc_nhc;
  wire            ld_inc_ibc_phc;

  wire            ld_credits;

  // >>>>>>>>>>>>>>>>>>>>>>>>> Zero In Checkers <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

  // 0in known_driven -var ld_inc_ibc_pdc
  // 0in known_driven -var ld_inc_ibc_nhc
  // 0in known_driven -var ld_inc_ibc_phc
  // 0in known_driven -var ld_credits

  // >>>>>>>>>>>>>>>>>>>>>>>>> RTL/Behavioral Model <<<<<<<<<<<<<<<<<<<<<<<<<<<

  //---------------------------------------------------------------------
  //   request flops
  //---------------------------------------------------------------------
  always @ (posedge clk)
    if (!rst_l) begin
      ibc_req <= 1'b0;
    end
    else begin
      ibc_req <= (ibc_ack ~^ ibc_req) ^ ibc_req;
    end

  always @ (posedge clk)
    if (!rst_l) begin
      d2p_ibc_req <= 1'b0;
        end
    else begin
      d2p_ibc_req <= ibc_req;
    end

  //---------------------------------------------------------------------
  //   PCIE FC credit flops
  //---------------------------------------------------------------------
  assign ld_inc_ibc_pdc = k2y_rel_enq & k2y_rel_rcd[8];
  assign ld_inc_ibc_nhc = credit_type[1] & is_ihb_rcd;
  assign ld_inc_ibc_phc = credit_type[0] & is_ihb_rcd;

  always @ (posedge clk)
    if ((!rst_l) | cib2iil_pec_drain) begin
      ibc_nhc <= 8'b0;
      ibc_phc <= 8'b0;
      ibc_pdc <= 12'b0;
    end
    else begin
      if (ld_inc_ibc_pdc) ibc_pdc <= ibc_pdc + 1'b1;
      if (ld_inc_ibc_nhc) begin
        ibc_nhc <= ibc_nhc + 1'b1;
      end
      else if (ld_inc_ibc_phc) begin
        ibc_phc <= ibc_phc + 1'b1;
      end
    end

  assign ld_credits = ibc_req ^ d2p_ibc_req;

  always @ (posedge clk)
    begin
      if (!rst_l) begin
        d2p_ibc_nhc <= 8'b0;
        d2p_ibc_phc <= 8'b0;
        d2p_ibc_pdc <= 12'b0;
      end
      else begin
        if (ld_credits) begin
          d2p_ibc_pdc <= ibc_pdc;
          d2p_ibc_phc <= ibc_phc;
          d2p_ibc_nhc <= ibc_nhc;
        end
      end
    end


  // >>>>>>>>>>>>>>>>>>>>>>>>> Instantiations <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

  // sync flop
//  pcie_common_sync_flop #(1) sync_flop(
//                                       .clk(clk),
//                                       .din(p2d_ibc_ack),
//                                       .dout(ibc_ack));
  cl_a1_clksyncff_4x sync_flop ( .d(p2d_ibc_ack), .si(1'b0), .q( ibc_ack), .so(),
        .l1clk(clk), .siclk(1'b0), .soclk(1'b0) );

endmodule // dmu_ilu_iil_crdtcnt