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//----------------------------------------------------------------------
//   Copyright 2010-2011 Mentor Graphics Corporation
//   Copyright 2010 Synopsys, Inc.
//   All Rights Reserved Worldwide
//
//   Licensed under the Apache License, Version 2.0 (the
//   "License"); you may not use this file except in
//   compliance with the License.  You may obtain a copy of
//   the License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in
//   writing, software distributed under the License is
//   distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
//   CONDITIONS OF ANY KIND, either express or implied.  See
//   the License for the specific language governing
//   permissions and limitations under the License.
//----------------------------------------------------------------------

// File: TLM2 Types

// Enum: uvm_tlm_phase_e 
//
// Nonblocking transport synchronization state values between
// an initiator and a target.
//
//  UNINITIALIZED_PHASE  - Defaults for constructor
//  BEGIN_REQ            - Beginning of request phase
//  END_REQ              - End of request phase
//  BEGIN_RESP           - Beginning of response phase
//  END_RESP             - End of response phase

typedef enum
  {
    UNINITIALIZED_PHASE,
    BEGIN_REQ,
    END_REQ,
    BEGIN_RESP,
    END_RESP
  } uvm_tlm_phase_e;

// Enum: uvm_tlm_sync_e
//
// Pre-defined phase state values for the nonblocking transport
// Base Protocol between an initiator and a target.
//
// UVM_TLM_ACCEPTED      - Transaction has been accepted
// UVM_TLM_UPDATED       - Transaction has been modified
// UVM_TLM_COMPLETED     - Execution of transaction is complete

typedef enum 
  {
    UVM_TLM_ACCEPTED,
    UVM_TLM_UPDATED,
    UVM_TLM_COMPLETED
  } uvm_tlm_sync_e;

// MACRO: `UVM_TLM_TASK_ERROR
//
// Defines Not-Yet-Implemented TLM tasks
`define UVM_TLM_TASK_ERROR "TLM-2 interface task not implemented"

// MACRO: `UVM_TLM_FUNCTION_ERROR
//
// Defines Not-Yet-Implemented TLM functions
`define UVM_TLM_FUNCTION_ERROR "TLM-2 interface function not implemented"

//
// Class: uvm_tlm_if
//
// Base class type to define the transport functions.
//
//  -  <nb_transport_fw>
//
//  - <nb_transport_bw>
//
//  - <b_transport>
//

class uvm_tlm_if #(type T=uvm_tlm_generic_payload,
               type P=uvm_tlm_phase_e);
   //----------------------------------------------------------------------
   // Group: tlm transport methods
   //
   // Each of the interface methods take a handle to the transaction to be 
   // transported and a reference argument for the delay. In addition, the 
   // nonblocking interfaces take a reference argument for the phase.
   //
   
   //----------------------------------------------------------------------
   // Function: nb_transport_fw
   //
   // Forward path call.
   // The first call to this method for a transaction marks the initial timing point.
   // Every call to this method may mark a timing point in the execution of the 
   // transaction. The timing annotation argument allows the timing points
   // to be offset from the simulation times at which the forward path is used.
   // The final timing point of a transaction may be marked by a call
   // to <nb_transport_bw> or a return from this or subsequent call to
   // nb_transport_fw.
   //
   // See <TLM2 Interfaces, Ports, Exports and Transport Interfaces Subset>
   // for more details on the semantics and rules of the nonblocking
   // transport interface.
   
  virtual function uvm_tlm_sync_e nb_transport_fw(T t, ref P p, input uvm_tlm_time delay);
    `uvm_error("nb_transport_fw", `UVM_TLM_FUNCTION_ERROR)
    return UVM_TLM_ACCEPTED;
  endfunction

   // Function: nb_transport_bw
   //
   // Implementation of the backward path.
   // This function MUST be implemented in the INITIATOR component class.
   //
   // Every call to this method may mark a timing point, including the final
   // timing point, in the execution of the transaction.
   // The timing annotation argument allows the timing point
   // to be offset from the simulation times at which the backward path is used.
   // The final timing point of a transaction may be marked by a call
   // to <nb_transport_fw> or a return from this or subsequent call to
   // nb_transport_bw.
   //
   // See <TLM2 Interfaces, Ports, Exports and Transport Interfaces Subset>
   // for more details on the semantics and rules of the nonblocking
   // transport interface.
   //
   // Example:
   //
   //| class master extends uvm_component;
   //     uvm_tlm_nb_initiator_socket #(trans, uvm_tlm_phase_e, this_t) initiator_socket;
   //|    ...
   //|    function void build_phase(uvm_phase phase);
   //        initiator_socket = new("initiator_socket", this, this);
   //|    endfunction
   //|
   //|    function uvm_tlm_sync_e nb_transport_bw(ref trans t,
   //|                                   ref uvm_tlm_phase_e p,
   //|                                   input uvm_tlm_time delay);
   //|        transaction = t;
   //|        state = p;
   //|        return UVM_TLM_ACCEPTED;
   //|    endfunction
   //|
   //|    ...
   //| endclass
   
  virtual function uvm_tlm_sync_e nb_transport_bw(T t, ref P p, input uvm_tlm_time delay);
    `uvm_error("nb_transport_bw", `UVM_TLM_FUNCTION_ERROR)
    return UVM_TLM_ACCEPTED;
  endfunction

   // Function: b_transport
   //
   // Execute a blocking transaction. Once this method returns,
   // the transaction is assumed to have been executed. Whether
   // that execution is successful or not must be indicated by the
   // transaction itself.
   //
   // The callee may modify or update the transaction object, subject
   // to any constraints imposed by the transaction class. The
   // initiator may re-use a transaction object from one call to
   // the next and across calls to b_transport(). 
   //
   // The call to b_transport shall mark the first timing point of the
   // transaction. The return from b_transport shall mark the final
   // timing point of the transaction. The timing annotation argument
   // allows the timing points to be offset from the simulation times
   // at which the task call and return are executed.
   
  virtual task b_transport(T t, uvm_tlm_time delay);
    `uvm_error("b_transport", `UVM_TLM_TASK_ERROR)
  endtask

endclass