Get_response() in sequence, Giving error below: Any suggestions? I am trying to learn UVM features with very small & simple example

UVM
, ,
1

In sequence:

  start_item(tr);
  Randomization
  finish_item(tr);
  get_response(tr);

In Driver:

  seq_item_port.get(tr);
  @(vif.cb) vif.in <= tr.in;
  tr.set_id_info(tr);
  seq_item_port.put(tr);


class base_tr extends uvm_sequence_item;
  `uvm_object_utils(base_tr)
  rand int in;
  function new(string name = "base_tr");
    super.new(name);
  endfunction 
  
  constraint c1 {
    in dist {1:=90, 5:=30};
  }
  virtual function string convert2string(); 
    return $sformatf("in = %0d", in);
  endfunction 
    
endclass


class base_seq extends uvm_sequence;
  `uvm_object_utils(base_seq)
  base_tr tr,tr_r;
  
  function new(string name = "base_seq");
    super.new(name);
  endfunction
  
  virtual task body();
    tr = base_tr::type_id::create("tr");
    for (int i=0; i<100; i++) begin
      start_item(tr);
      if(!tr.randomize()) begin
        `uvm_error(get_type_name(), $sformatf("could not randomize"))
      end
      finish_item(tr);
      get_response(tr);
      `uvm_info(get_type_name(), $sformatf(" after finish_item in = %d",tr.in), UVM_LOW);
    end  
  endtask
endclass

class base_drv extends uvm_driver#(base_tr);
  `uvm_component_utils(base_drv)
  
  virtual if_name vif;
  base_tr tr,tr_r;
  function new(string name = "base_drv", uvm_component parent = null);
    super.new(name,parent);
  endfunction
  
  virtual function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    uvm_config_db#(virtual if_name)::get(this,"", "if", vif);
  endfunction 
  
  virtual task run_phase (uvm_phase phase);
    super.run_phase(phase);
    tr = base_tr::type_id::create("tr");
    forever begin 
      seq_item_port.get(tr);
      @(vif.cb) vif.in <= tr.in;
      tr.set_id_info(tr);
      seq_item_port.put(tr);
    end 
  endtask 
endclass

Link to entire code : debug response: don't edit. VerificationAcademy - EDA Playground

Error-[ICTTFC] Incompatible complex type usage
testbench.sv, 46
Incompatible complex type usage in task or function call.
The following expression is incompatible with the formal parameter of the
task. The type of the actual is ‘class $unit::base_tr’, while the type of
the formal is ‘class uvm_pkg::uvm_sequence_item’. Expression: this.tr
Source info:
uvm_pkg::\uvm_sequence#(uvm_pkg::uvm_sequence_item,uvm_pkg::uvm_sequence_item)::get_response
(this, this.tr, /* transaction_id = (-1) */);

2

In reply to vickydhudashia:
Each sequence which generates seq_items has to be parameterized with the corresponding seq_item (see line 27 in the testbench.

class base_seq extends uvm_sequence #(base_tr);
3

In reply to chr_sue:

Thank you chr_sue.
I was scratching my head about whats going wrong here.
I thought sequencer will handle this since get_response is uvm_sequence_item method which is internally connected to sequencer’s seq_item_port.
I was under impression that only sequencer, analysis port/export and driver need this transaction type flowing through the entire tb.
This really helped!

Thanks,
Vicky Dhudashia

4

In reply to chr_sue:

Hi Chr_sue,
if i could get your help looking into this : adding uvm_callback
This is how I am doing it, added comments

class base_drv extends uvm_driver#(base_tr);
  `uvm_component_utils(base_drv)
  `uvm_register_cb(base_drv, dr_callback_abs)                      // *************** UVM Callback
 ...
  virtual task run_phase (uvm_phase phase);
    super.run_phase(phase);
    tr = base_tr::type_id::create("tr");
    forever begin 
      seq_item_port.get_next_item(tr);
      `uvm_do_callbacks(base_drv, dr_callback_abs, dr_cb_t1());     // *************** UVM Callback
      @(vif.cb) vif.in <= tr.in;
      `uvm_do_callbacks(base_drv, dr_callback_abs, dr_cb_t2());     // *************** UVM Callback
      seq_item_port.item_done();
    end 
  endtask 
endclass

class dr_callback_abs extends uvm_callback;                         // *************** UVM Callback abstract class
  `uvm_object_utils(dr_callback_abs)
  
  function new(string name = "dr_callback_abs");
    super.new(name);
  endfunction 
  
  virtual task dr_cb_t1;
  endtask
  
  virtual task dr_cb_t2;
  endtask
  
endclass

class dr_callback extends dr_callback_abs;                         // *************** UVM Callbackimplementation class
  `uvm_object_utils(dr_callback)
  
  function new(string name = "dr_callback");
    super.new(name);
  endfunction 
  
  virtual task dr_cb_t1();//base_tr cb_t);
    `uvm_info(get_type_name(),$sformatf(" YOU ARE Inside dr_cb_t1 method"), UVM_LOW);
  endtask
  
  virtual task dr_cb_t2();//base_tr cb_t);
    `uvm_info(get_type_name(),$sformatf(" YOU ARE Inside dr_cb_t2 method"), UVM_LOW);
  endtask
endclass

// test file
`include "seq_1.sv"
`include "dr_callback.sv"                           // *************** UVM Callback:   included callback class file (which has callback abstract class and implementation class) in test file

class all_8_test extends base_test;
  dr_callback cb;                                   // *************** UVM Callback:  create handle of implementation class
  `uvm_component_utils(all_8_test)
  
  
  function new(string name = "all_8_test", uvm_component parent = null);
    super.new(name, parent);
    set_type_override_by_type(base_test::get_type(), all_8_test::get_type());
    set_type_override_by_type(base_seq::get_type(), seq_1::get_type());
    cb = dr_callback::type_id::create("cb", this);                             // *************** UVM Callback:  create callback object
    uvm_callbacks#(base_drv, dr_callback_abs)::add(env.agent.dr, cb);          // *************** UVM Callback:  add callback to driver
  endfunction
  
  task run_phase(uvm_phase phase);
    super.run_phase(phase);    
    phase.phase_done.set_drain_time(this,3);
  endtask
  
endclass

Here is the code link : UVM : In progress - EDA Playground

I think this is something to do where to include callback class file when compiling. I have checked syntax multiple time, don’t see anything wrong there.
Right now I have included callback class file name it in my extended test file

Thanks for your time.

Error-[SE] Syntax error
Following verilog source has syntax error :
Token ‘dr_callback_abs’ not recognized as a type. Please check
whether it is misspelled, not visible/valid in the current context, or not
properly imported/exported. This is occurring in a context where a variable
declaration, a statement, or a sequence expression is expected. Either the
declaration type is not known or this is incorrect syntax.
“base_drv.sv”, 25 (expanding macro): token is ‘=’
`uvm_do_callbacks(base_drv, dr_callback_abs, dr_cb_t1()); //
*************** UVM Callback
^

#0, uvm_do_obj_callbacks(T=base_drv, CB=dr_callback_abs, OBJ=this, METHOD=dr_cb_t1()) : “/apps/vcsmx/vcs/Q-2020.03-SP1-1//etc/uvm-1.2/src/macros/uvm_callback_defines.svh”:165
#1, uvm_do_callbacks(T=base_drv, CB=dr_callback_abs, METHOD=dr_cb_t1()) : “/apps/vcsmx/vcs/Q-2020.03-SP1-1//etc/uvm-1.2/src/macros/uvm_callback_defines.svh”:140
full expansion of macro (uvm_do_callbacks), error at line 3
(* native_uvm *)begin
uvm_callback_iter#(base_drv,dr_callback_abs) iter = new(this);
=> dr_callback_abs cb = iter.first();
while(cb != null) begin
`uvm_cb_trace_noobj(cb,$sformatf(“Executing callback method ‘dr_cb_t1()’ for callback %s (dr_callback_abs) from %s (base_drv)”,cb.get_name(), this.get_full_name()))
…

5

In reply to vickydhudashia:

In reply to chr_sue:
Thank you chr_sue.
I was scratching my head about whats going wrong here.
I thought sequencer will handle this since get_response is uvm_sequence_item method which is internally connected to sequencer’s seq_item_port.
I was under impression that only sequencer, analysis port/export and driver need this transaction type flowing through the entire tb.
This really helped!
Thanks,
Vicky Dhudashia

You are not right. get_response is a method of uvm_sequence and not of uvm_sequence_item.
And this is how we are applying this method in the sequence.

6

In reply to chr_sue:

Thank you chr_sue

7

In reply to vickydhudashia:

With respect to the callback solution, this sounds like your compilation order is wrong or you do not compile the callback files.
Please check this.
And you have other weaknesses in your code:
(1) in the agent:

sqr = base_seqr::type_id::create("sqr", this); // without a parameter, because base seqr is not parameterized.

(2) You are constructing components and objects in the constructor. This is legal but might result in problems. components have to be constructed in the build_phase and objects are constructed in the run_phase.

8

In reply to chr_sue:

Thanks a lot chr_sue for taking your time to look at my messy code.
To you it might look like very small details but for me it’s a great feedback. I will use the coding practice you suggested.

Yes I was able to solve that issue with callback. it was the order of the files provided to compiler.