UVM on uvm_config_db clarification

UVM
,
1

Hello everybody,

Just wanted to ask a few questions regarding uvm_config_db method on get and set.

I understand that there are 4 parameters in regards to using the uvm_config_db method on get and set.

Below is a portion of my code.

class comp1 extends uvm_component;
    `uvm_component_utils(comp1)

    int comp1_data = 0; 

    function new(input string path = "comp1", uvm_component parent = null);
        super.new(path, parent);

    endfunction

    virtual function void build_phase(uvm_phase phase);
        super.build_phase(phase);

        if(!uvm_config_db#(int)::get(null, "uvm_test_top", "data", comp1_data))  
            `uvm_error("comp1", "Unable to share data");

    endfunction 

    virtual task run_phase(uvm_phase phase);
        phase.raise_objection(this);
            `uvm_info("comp1", $sformatf("Data rcvd comp1 : %0d", comp1_data), UVM_NONE);
        phase.drop_objection(this); 

    endtask

endclass

class comp2 extends uvm_component;
    `uvm_component_utils(comp2)

    int comp2_data = 0; 

    function new(input string path = "comp2", uvm_component parent = null);
        super.new(path, parent);

    endfunction

    virtual function void build_phase(uvm_phase phase);
        super.build_phase(phase);

        if(!uvm_config_db#(int)::get(this, "", "data", comp2_data))
            `uvm_error("comp2", "Unable to share data");

    endfunction 

    virtual task run_phase(uvm_phase phase);
        phase.raise_objection(this);
            `uvm_info("comp2", $sformatf("Data rcvd comp2 : %0d", comp2_data), UVM_NONE);
        phase.drop_objection(this); 

    endtask

endclass


// top level
module tb (

);
    int data = 256; 

    initial begin
        uvm_config_db #(int)::set(null, "uvm_test_top", "data", data);
        run_test("the_test");

    end


endmodule

I just want to know if I am understanding right - so the use of the parameters is to make sure only variables of certain classes would be updated? I know that because my data variable in comp2 does not have the same parameters as the tb module, the compiler results in an error. So I think my question is

  • First, are the parameters in set and get method provide some sort of a path in order to provide some sort of identification?
  • Second, how would I be able to set a different value to comp2? Do I need to create another get-set method to do this?

Also much appreciated if I can get some explanation on the purpose and usage of the parameters in get and set method in uvm_db_config

Thank you!

Sangwoo

2

UVM Basics covers using the configuration database and explains all the parameters.