UVM callback

最新推荐文章于 2024-11-27 21:04:40 发布

原创最新推荐文章于 2024-11-27 21:04:40 发布 · 307 阅读

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#UVM #callback

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本文详细介绍了UVM（Universal Verification Methodology）中的回调机制，包括如何在UVM驱动和序列中实现和使用回调。通过步骤化的指导，展示了如何创建空的回调类，注册回调类，以及在实际的功能类中调用这些回调。

UVM callback example

Callback in uvm_driver

step1

实现空的callback class

class driver_cb extends uvm_callback;
  extern virtual task <callback task/function>;
endclass

step 2

实现functional class

class my_driver extends uvm_driver;
  typedef driver_cb cb_type;
  typedef m_driver this_type;

  `uvm_component_utils(my_driver)
  `uvm_register_cb(this_type, cb_type)
  
  // in functional task
  //`uvm_do_callback(this_type, cb_type, cb_task(this, m_item));
  task run_phase(uvm_phase phase);
    `uvm_do_callback(this_type, cb_type, cb_task(this, m_item));
    drive_pkt();
    //`uvm_do_callbacks(driver,driver_callback,post_drive());
  endtask
endclass

step3

实现具体 callback class 并且注入

class driver_cb_rready extends driver_cb;
  // concept
endclass


class m_case/m_env extends uvm_test/uvm_env;
  typedef uvm_callbacks#(m_driver, driver_cb) driver_cb_pool;

  // build_phase
  driver_cb_rready drv_cb_rrdy;
  drv_cb_rrdy = driver_cb_rready::type_id::create("drv_cb_rrdy");

  // connect_phase
  driver_cb_pool::add(m_env.m_agt.m_drv, drv_cb_rrdy);
endclass

Callback in uvm_sequence

step1 实现空的callback class

class mem_callback extends uvm_callback;
    
  `uvm_object_utils(mem_callback)
    
  function new(string name = "mem_callback");
    super.new(name);
  endfunction
    
  virtual task update_pkt(ref mem_seq_item pkt); endtask
endclass

step2 register the callback class to sequencer

class mem_sequencer extends uvm_sequencer#(mem_seq_item);
 
  `uvm_component_utils(mem_sequencer)
  `uvm_register_cb(mem_sequencer,mem_callback)
   
  //---------------------------------------
  //constructor
  //---------------------------------------
  function new(string name, uvm_component parent);
    super.new(name,parent);
  endfunction
   
endclass

step3 place the callback hook on the sequence

class mem_sequence extends uvm_sequence#(mem_seq_item);
   
  `uvm_object_utils(mem_sequence)
 
  //---------------------------------------
  //Constructor
  //---------------------------------------
  function new(string name = "mem_sequence");
    super.new(name);
  endfunction
   
  `uvm_declare_p_sequencer(mem_sequencer)
   
  //---------------------------------------
  // create, randomize and send the item to driver
  //---------------------------------------
  virtual task body();
    req = mem_seq_item::type_id::create("req");
    wait_for_grant();
    req.randomize();
    `uvm_do_obj_callbacks(mem_sequencer,mem_callback,p_sequencer,update_pkt(req));
    send_request(req);
    wait_for_item_done();
  endtask
endclass

step4 实现具体 callback class 并且注入

class user_callback extends mem_callback;
   
  `uvm_object_utils(user_callback)
   
  function new(string name = "user_callback");
    super.new(name);
  endfunction
   
  task update_pkt(ref mem_seq_item pkt);
    `uvm_info("USER_CALLBACK","[update_pkt] before packet modification",UVM_LOW);
    pkt.print();
    pkt.addr = ~pkt.addr;
    `uvm_info("USER_CALLBACK","[update_pkt] after packet modification",UVM_LOW);
    pkt.print();
  endtask
endclass


class user_callback_test extends mem_test;
  user_callback callback_1;
   
  `uvm_component_utils(user_callback_test)
   
  function new(string name = "user_callback_test", uvm_component parent=null);
    super.new(name,parent);
  endfunction
   
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    callback_1 = user_callback::type_id::create("callback_1", this);
  endfunction
   
  function void end_of_elaboration();
    uvm_callbacks#(mem_sequencer,mem_callback)::add(env.mem_agnt.sequencer,callback_1);
  endfunction : end_of_elaboration
endclass