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//------------------------------------------------------------------------------
//   Copyright 2007-2011 Mentor Graphics Corporation
//   Copyright 2007-2011 Cadence Design Systems, Inc. 
//   Copyright 2010-2011 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.
//------------------------------------------------------------------------------


//------------------------------------------------------------------------------
//
// CLASS: uvm_sequencer_param_base #(REQ,RSP)
//
// Extends <uvm_sequencer_base> with an API depending on specific
// request (REQ) and response (RSP) types.
//------------------------------------------------------------------------------

class uvm_sequencer_param_base #(type REQ = uvm_sequence_item,
                                 type RSP = REQ) extends uvm_sequencer_base;

  typedef uvm_sequencer_param_base #( REQ , RSP) this_type;
  typedef REQ req_type;
  typedef RSP rsp_type;

  REQ m_last_req_buffer[$];
  RSP m_last_rsp_buffer[$];

  protected int m_num_last_reqs = 1;
  protected int num_last_items = m_num_last_reqs;
  protected int m_num_last_rsps = 1;
  protected int m_num_reqs_sent;
  protected int m_num_rsps_received;
  uvm_sequencer_analysis_fifo #(RSP) sqr_rsp_analysis_fifo;


  // Function: new
  //
  // Creates and initializes an instance of this class using the normal 
  // constructor arguments for uvm_component: name is the name of the instance,
  // and parent is the handle to the hierarchical parent, if any.
  //
  extern function new (string name, uvm_component parent);


  // Function: send_request
  //
  // The send_request function may only be called after a wait_for_grant call.
  // This call will send the request item, t,  to the sequencer pointed to by
  // sequence_ptr. The sequencer will forward it to the driver. If rerandomize
  // is set, the item will be randomized before being sent to the driver.
  //
  extern virtual function void send_request(uvm_sequence_base sequence_ptr,
                                            uvm_sequence_item t,
                                            bit rerandomize = 0);


  // Function: get_current_item
  //
  // Returns the request_item currently being executed by the sequencer. If the
  // sequencer is not currently executing an item, this method will return ~null~.
  //
  // The sequencer is executing an item from the time that get_next_item or peek
  // is called until the time that get or item_done is called.
  //
  // Note that a driver that only calls get() will never show a current item,
  // since the item is completed at the same time as it is requested.
  //
  function REQ get_current_item();
    REQ t;
    if (m_req_fifo.try_peek(t) == 0)
      return null;
    return t;
  endfunction


  //----------------
  // Group: Requests
  //----------------

  // Function: get_num_reqs_sent
  //
  // Returns the number of requests that have been sent by this sequencer.
  //
  extern function int get_num_reqs_sent();


  // Function: set_num_last_reqs
  //
  // Sets the size of the last_requests buffer.  Note that the maximum buffer
  // size is 1024.  If max is greater than 1024, a warning is issued, and the
  // buffer is set to 1024.  The default value is 1.
  //
  extern function void set_num_last_reqs(int unsigned max);


  // Function: get_num_last_reqs
  //
  // Returns the size of the last requests buffer, as set by set_num_last_reqs.

  extern function int unsigned get_num_last_reqs();


  // Function: last_req
  //
  // Returns the last request item by default.  If n is not 0, then it will get
  // the n�th before last request item.  If n is greater than the last request
  // buffer size, the function will return ~null~.
  //
  function REQ last_req(int unsigned n = 0);
    if(n > m_num_last_reqs) begin
      uvm_report_warning("HSTOB",
        $sformatf("Invalid last access (%0d), the max history is %0d", n,
        m_num_last_reqs));
      return null;
    end
    if(n == m_last_req_buffer.size())
      return null;
  
    return m_last_req_buffer[n];
  endfunction



  //-----------------
  // Group: Responses
  //-----------------

  // Port: rsp_export
  //
  // Drivers or monitors can connect to this port to send responses
  // to the sequencer.  Alternatively, a driver can send responses 
  // via its seq_item_port.
  //
  //|  seq_item_port.item_done(response)
  //|  seq_item_port.put(response)
  //|  rsp_port.write(response)   <--- via this export
  //
  // The rsp_port in the driver and/or monitor must be connected to the
  // rsp_export in this sequencer in order to send responses through the
  // response analysis port.
  
  uvm_analysis_export #(RSP) rsp_export;


  // Function: get_num_rsps_received
  //
  // Returns the number of responses received thus far by this sequencer.

  extern function int get_num_rsps_received();


  // Function: set_num_last_rsps
  //
  // Sets the size of the last_responses buffer.  The maximum buffer size is
  // 1024. If max is greater than 1024, a warning is issued, and the buffer is
  // set to 1024.  The default value is 1.
  //
  extern function void set_num_last_rsps(int unsigned max);


  // Function: get_num_last_rsps
  //
  // Returns the max size of the last responses buffer, as set by
  // set_num_last_rsps.
  //
  extern function int unsigned get_num_last_rsps();


  // Function: last_rsp
  //
  // Returns the last response item by default.  If n is not 0, then it will
  // get the nth-before-last response item.  If n is greater than the last
  // response buffer size, the function will return ~null~.
  //
  function RSP last_rsp(int unsigned n = 0);
    if(n > m_num_last_rsps) begin
      uvm_report_warning("HSTOB",
        $sformatf("Invalid last access (%0d), the max history is %0d", n,
        m_num_last_rsps));
      return null;
    end
    if(n == m_last_rsp_buffer.size())
      return null;
  
    return m_last_rsp_buffer[n];
  endfunction



  // Internal methods and variables; do not use directly, not part of standard

  /* local */ extern function void m_last_rsp_push_front(RSP item);
  /* local */ extern function void put_response (RSP t);
  /* local */ extern virtual function void build_phase(uvm_phase phase);
  /* local */ extern virtual function void connect_phase(uvm_phase phase);
  /* local */ extern virtual function void do_print (uvm_printer printer);
  /* local */ extern virtual function void analysis_write(uvm_sequence_item t);
  /* local */ extern function void m_last_req_push_front(REQ item);

  /* local */ uvm_tlm_fifo #(REQ) m_req_fifo;

endclass


//------------------------------------------------------------------------------
// IMPLEMENTATION
//------------------------------------------------------------------------------

// new
// ---

function uvm_sequencer_param_base::new (string name, uvm_component parent);
  super.new(name, parent);

  rsp_export              = new("rsp_export", this);
  sqr_rsp_analysis_fifo   = new("sqr_rsp_analysis_fifo", this);
  sqr_rsp_analysis_fifo.print_enabled = 0;
  m_req_fifo              = new("req_fifo", this);
  m_req_fifo.print_enabled = 0;
endfunction


// do_print
// --------

function void uvm_sequencer_param_base::do_print (uvm_printer printer);
  super.do_print(printer);
  printer.print_field_int("num_last_reqs", m_num_last_reqs, $bits(m_num_last_reqs), UVM_DEC);
  printer.print_field_int("num_last_rsps", m_num_last_rsps, $bits(m_num_last_rsps), UVM_DEC);
endfunction


// connect_phase
// -------------

function void uvm_sequencer_param_base::connect_phase(uvm_phase phase);
  super.connect_phase(phase);
  rsp_export.connect(sqr_rsp_analysis_fifo.analysis_export);
endfunction


// build_phase
// -----------

function void uvm_sequencer_param_base::build_phase(uvm_phase phase);
  super.build_phase(phase);
  sqr_rsp_analysis_fifo.sequencer_ptr = this;
endfunction


// send_request
// ------------

function void uvm_sequencer_param_base::send_request(uvm_sequence_base sequence_ptr,
                                                     uvm_sequence_item t,
                                                     bit rerandomize = 0);
  REQ param_t;

  if (sequence_ptr == null) begin
    uvm_report_fatal("SNDREQ", "Send request sequence_ptr is null", UVM_NONE);
  end

  if (sequence_ptr.m_wait_for_grant_semaphore < 1) begin
    uvm_report_fatal("SNDREQ", "Send request called without wait_for_grant", UVM_NONE);
  end
  sequence_ptr.m_wait_for_grant_semaphore--;
  
  if ($cast(param_t, t)) begin
    if (rerandomize == 1) begin
      if (!param_t.randomize()) begin
        uvm_report_warning("SQRSNDREQ", "Failed to rerandomize sequence item in send_request");
      end
    end
    if (param_t.get_transaction_id() == -1) begin
      param_t.set_transaction_id(sequence_ptr.m_next_transaction_id++);
    end
    m_last_req_push_front(param_t);
  end else begin
    uvm_report_fatal(get_name(),$sformatf("send_request failed to cast sequence item"), UVM_NONE);
  end

  param_t.set_sequence_id(sequence_ptr.m_get_sqr_sequence_id(m_sequencer_id, 1));
  t.set_sequencer(this);
  if (m_req_fifo.try_put(param_t) != 1) begin
    uvm_report_fatal(get_full_name(), "Concurrent calls to get_next_item() not supported. Consider using a semaphore to ensure that concurrent processes take turns in the driver", UVM_NONE);
  end

  m_num_reqs_sent++;
  // Grant any locks as soon as possible
  grant_queued_locks();
endfunction


// put_response
// ------------

function void uvm_sequencer_param_base::put_response (RSP t);
  uvm_sequence_base sequence_ptr;
  
  if (t == null) begin
    uvm_report_fatal("SQRPUT", "Driver put a null response", UVM_NONE);
  end

  m_last_rsp_push_front(t);
  m_num_rsps_received++;

  // Check that set_id_info was called
  if (t.get_sequence_id() == -1) begin
`ifndef CDNS_NO_SQR_CHK_SEQ_ID
    uvm_report_fatal("SQRPUT", "Driver put a response with null sequence_id", UVM_NONE);
`endif
    return;
  end
    
  sequence_ptr = m_find_sequence(t.get_sequence_id());

  if (sequence_ptr != null) begin
    // If the response_handler is enabled for this sequence, then call the response handler
    if (sequence_ptr.get_use_response_handler() == 1) begin
      sequence_ptr.response_handler(t);
      return;
    end
    
    sequence_ptr.put_response(t);
  end
  else begin
    uvm_report_info("Sequencer", 
                    $sformatf("Dropping response for sequence %0d, sequence not found.  Probable cause: sequence exited or has been killed", 
                              t.get_sequence_id()));
  end
endfunction


// analysis_write
// --------------

function void uvm_sequencer_param_base::analysis_write(uvm_sequence_item t);
  RSP response;

  if (!$cast(response, t)) begin
    uvm_report_fatal("ANALWRT", "Failure to cast analysis port write item", UVM_NONE);
  end
  put_response(response);
endfunction


// get_num_reqs_sent
// -----------------

function int uvm_sequencer_param_base::get_num_reqs_sent();
  return m_num_reqs_sent;
endfunction


// get_num_rsps_received
// ---------------------

function int uvm_sequencer_param_base::get_num_rsps_received();
  return m_num_rsps_received;
endfunction


// set_num_last_reqs
// -----------------

function void uvm_sequencer_param_base::set_num_last_reqs(int unsigned max);
  if(max > 1024) begin
    uvm_report_warning("HSTOB", 
      $sformatf("Invalid last size; 1024 is the maximum and will be used"));
    max = 1024;
  end

  //shrink the buffer if necessary
  while((m_last_req_buffer.size() != 0) && (m_last_req_buffer.size() > max))
    void'(m_last_req_buffer.pop_back());

  m_num_last_reqs = max;
  num_last_items = max;

endfunction


// get_num_last_reqs
// -----------------

function int unsigned uvm_sequencer_param_base::get_num_last_reqs();
  return m_num_last_reqs;
endfunction


// m_last_req_push_front
// ---------------------

function void uvm_sequencer_param_base::m_last_req_push_front(REQ item);
  if(!m_num_last_reqs)
    return;
 
  if(m_last_req_buffer.size() == m_num_last_reqs)
    void'(m_last_req_buffer.pop_back());

  this.m_last_req_buffer.push_front(item);
endfunction


// set_num_last_rsps
// -----------------

function void uvm_sequencer_param_base::set_num_last_rsps(int unsigned max);
  if(max > 1024) begin
    uvm_report_warning("HSTOB", 
      $sformatf("Invalid last size; 1024 is the maximum and will be used"));
    max = 1024;
  end

  //shrink the buffer
  while((m_last_rsp_buffer.size() != 0) && (m_last_rsp_buffer.size() > max)) begin
    void'(m_last_rsp_buffer.pop_back());
  end

  m_num_last_rsps = max;

endfunction


// get_num_last_rsps
// -----------------

function int unsigned uvm_sequencer_param_base::get_num_last_rsps();
  return m_num_last_rsps;
endfunction


// m_last_rsp_push_front
// ---------------------

function void uvm_sequencer_param_base::m_last_rsp_push_front(RSP item);
  if(!m_num_last_rsps)
    return;
 
  if(m_last_rsp_buffer.size() == m_num_last_rsps)
    void'(m_last_rsp_buffer.pop_back());

  this.m_last_rsp_buffer.push_front(item);
endfunction