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

// ========== Copyright Header Begin ==========================================
//
// OpenSPARC T2 Processor File: dmu_imu_rds_mondo.v
// Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved
// 4150 Network Circle, Santa Clara, California 95054, U.S.A.
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// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; version 2 of the License.
//
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
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// ========== Copyright Header End ============================================
module dmu_imu_rds_mondo (

                // Clock and Reset

                clk,
                rst_l,

                // Static ID for IMU for Mondo's

                j2d_jid,
                j2d_instance_id,

                // Pipeline Input Select

                pipe_select_in,

                // Pipeline Output Select and Outputs

                pipe_select_out,
                mondo_d_ptr,
                mondo_jid

                );


//############################################################################
//                              PORT DECLARATIONS
//############################################################################

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


  //------------------------------------------------------------------------
  // Static ID for IMU for Mondo's
  //------------------------------------------------------------------------
  input [`FIRE_J2D_JID_WDTH-1:0]                j2d_jid;
  input [`FIRE_J2D_INSTANCE_ID_WDTH-1:0]        j2d_instance_id;


  //------------------------------------------------------------------------
  // Pipeline Input Select
  //------------------------------------------------------------------------
  input                 pipe_select_in;

  //------------------------------------------------------------------------
  // Pipeline Output Select and Outputs
  //------------------------------------------------------------------------
  output                pipe_select_out;
  output  [3:0]         mondo_d_ptr;
  output  [4:0]         mondo_jid;


//############################################################################
//                              PARAMETERS
//############################################################################

  parameter MONDO_FIRST_DPTR    =   4'b1100;
  parameter MONDO_LAST_DPTR     =   4'b1111;


//############################################################################
//                              SIGNAL DECLARATIONS
//############################################################################


//**************************************************
// Wire
//**************************************************

//**************************************************
// Registers that Are Not Flops
//**************************************************
 reg  [4:0]     jid;


//**************************************************
// Registers that Are Flops
//**************************************************
 reg            pipe_select_out;
 reg  [3:0]     mondo_d_ptr;
 reg  [4:0]     mondo_jid;
 reg  [3:0]     dptr;

//############################################################################
//                              ZERO IN CHECKERS
//############################################################################
  //---------------------------------------------------------------------
  // Range Checkers
  //---------------------------------------------------------------------

   //0in range -var dptr -min MONDO_FIRST_DPTR -max MONDO_LAST_DPTR
   //0in range -var jid  -min 5'h1c            -max 5'h1f


//############################################################################
//                              COMBINATIONAL LOGIC
//############################################################################

//--------------------------------------------------------------------------
// Use the ID from the JBC Core to select which ID to use for the Mondo
//--------------------------------------------------------------------------

always @(j2d_jid or j2d_instance_id)
    begin
      case ({j2d_jid,j2d_instance_id}) // synopsys parallel_case full_case infer_mux
        2'b00: jid  = 5'h1c;
        2'b01: jid  = 5'h1d;
        2'b10: jid  = 5'h1e;
        2'b11: jid  = 5'h1f;
      endcase
    end


//############################################################################
//                              SEQUENTIAL LOGIC
//############################################################################

//--------------------------------------------------------------------------
// ALLOCATION of the DPTR for the MSI DIU RAM
//
//      - The RAM is 1K with 64 rows and holds 16 cachelines of data
//      - Space is alloctaed on cachline boundry
//      - 16 lines is 4 bits
//      - C-F are dedicated to the Mondo (1100-1111)
//      - Also need three other bits
//              - upper 2 MSB are to identify ram type in DIU
//                      - 00     TLP
//                      - 01     PIO
//                      - 10     MSI/Mondo RAM
//              - 1 extra bit to unify the read address space as TLP is 2K
//
//
//      - Reset the value to the first RAM location
//
//      - If new requests comes in advance the dptr in cicular fashion
//      - If no new request hold the value.
//
//--------------------------------------------------------------------------

always @ (posedge clk)
  if (!rst_l)
       dptr <= MONDO_FIRST_DPTR;
  else if (pipe_select_in)
         begin
           if(dptr == MONDO_LAST_DPTR)
               dptr <= MONDO_FIRST_DPTR;
           else
                dptr <= dptr + 1;
         end
  else
       dptr <= dptr;

//--------------------------------------------------------------------------
// FLOP THE OUTPUTS
//
//--------------------------------------------------------------------------

always @ (posedge clk)
  if (!rst_l)
      begin                             // At reset reset all of them to zero.
       pipe_select_out  <= 1'b0;
       mondo_jid        <= 5'h0;
       mondo_d_ptr      <= 4'h0;
      end
  else
      begin
       pipe_select_out  <= pipe_select_in;
       mondo_jid        <= jid;
       mondo_d_ptr      <= dptr;
      end


//############################################################################
//                              MODULE INSTANTIATIONS
//############################################################################


endmodule