UVM——callback机制应用示例

对应代码：

1、在UVM组件中主操作函数或者任务之前或者之后内嵌callback函数或任务

 1 class driver extends uvm_driver #(transaction);

 2     `uvm_register_cb(driver, driver_callback);         //登记

 3     ...

 4     virtual task run_phase(uvm_phase phase)l

 5          forever begin

 6              seq_item_port.get_next_item(req);

 7              `uvm_do_callbacks(driver, driver_callback, pre_send(this, req));      //使用宏嵌入函数或任务

 8              send(req);

 9              `uvm_do_callbacks(driver, driver_callback, post_send(this, req));    // 就是在哪个类中，使用哪个callback，以及这个callback的哪个方法

10              seq_item_port.item_done();

11          end

12

13 endclass: drvier

14

2、创建一个uvm_callback 空壳类（facade class）

 1 typedef class driver;

 2 class driver_callback extends uvm_callback;

 3     function new(string name = "driver_callback");

 4          super.new(name);

 5     endfunction: new

 6

 7     virtual task pre_send(driver drv, transaction tr);　　　//这是注入错误的

 8     endtask

 9

10     virtual task post_send(driver drv, transaction tr);　　//这是用来收集覆盖率的

11     endtask

12 endcalss: driver_callback

3、从callback空壳类扩展

　　①注入错误

1 class driver_error_callback extends driver_callback;

2     virtual task pre_send(driver drv, transaction tr);

3          drv.req.payload.delete()

4     endtask: pre_send

5 endclass: driver_error_callback

　　②收集覆盖率

 1 class driver_cov_callback extends driver_callback;

 2     covergroup drv_cov with function sample(transaction tr);

 3          coverpoint tr.sa;

 4          coverpoint tr.da;

 5     endcovergroup

 6

 7     function new();

 8          drv_cov = new();

 9     endfunction: new

10

11     virtual task post_send(driver drv, transaction tr);

12          drv_cov.sample(tr);

13     endtask: pre_send

14 endclass: driver_error_callback

4、在验证环境中创建并登记UVM callback 实例

　　①

1 class driver_err_test extends test_base;

2     driver_error_callback drv_err_cb;                           // ↓

3     virtual function void connect_phase(uvm_phase, phase);

4          super.connect_phase(phase);

5          drv_err_cb = new();                                              //创建

6          uvm_callbacks #(driver, driver_callback)::add(env.drv, drv_err_cb);     // 登记对象

7          uvm_callbacks #(driver, driver_callback)::display();  //方便调试

8     endfunction: connect_phase

9 endcalss: driver_err_test

　　②

 1 class driver_cov_test extends test_base;

 2     ...

 3     driver_cov_callback drv_err_cb;                           // ↓

 4     virtual function void connect_phase(uvm_phase, phase);

 5          super.connect_phase(phase);

 6          drv_cov_cb = new();                                              //创建

 7          uvm_callbacks #(driver, driver_callback)::add(env.drv, drv_cov_cb);     // 登记对象

 8          uvm_callbacks #(driver, driver_callback)::display();  //方便调试

 9     endfunction: connect_phase

10 endcalss: driver_cov_test

这个例子就到此结束了。还有一个例子。

两个例子基本一致的，就是个别宏的使用方法有点小异。

  1 `include "uvm_macros.svh"

  2

  3 package bus_driver_pkg;

  4

  5 import uvm_pkg::*;

  6

  7 typedef class bus_driver;

  8 typedef class bus_driver_cb;

  9 typedef uvm_callbacks #(bus_driver,bus_driver_cb) bus_driver_cbs_t;　　// 这样定义好之后，使用::add的时候就不要带那么多参数了。

 10

 11 class bus_tr extends uvm_transaction;

 12   rand int addr;

 13   rand int data;

 14   virtual function string convert2string();

 15     convert2string = $sformatf("addr=%0h data=%0h",addr,data);

 16   endfunction

 17 endclass

 18

 19 virtual class bus_driver_cb extends uvm_callback; 　　// 空壳类

 20

 21   virtual function bit trans_received(bus_driver driver, bus_tr tr);

 22     return 0;

 23   endfunction

 24

 25   virtual task trans_executed(bus_driver driver, bus_tr tr);

 26   endtask

 27

 28   function new(string name="bus_driver_cb_inst");

 29     super.new(name);

 30   endfunction

 31

 32   static string type_name = "bus_driver_cb";

 33

 34   virtual function string get_type_name();

 35     return type_name;

 36   endfunction

 37

 38 endclass

 39

 40 class bus_driver extends uvm_component;

 41

 42   uvm_blocking_put_imp #(bus_tr,bus_driver) in;

 43

 44   `uvm_register_cb(bus_driver, bus_driver_cb)　　　　// 注册

 45

 46   function new (string name, uvm_component parent=null);

 47     super.new(name,parent);

 48     in = new("in",this);

 49   endfunction

 50

 51   static string type_name = "bus_driver";

 52

 53   virtual function string get_type_name();

 54     return type_name;

 55   endfunction

 56

 57   virtual function bit trans_received(bus_tr tr);

 58     `uvm_do_callbacks_exit_on(bus_driver,bus_driver_cb,trans_received(this,tr),1)　　　　// 这里的callback函数用在了主任务所调用的函数里，也是可以的

 59   endfunction

 60

 61   virtual task trans_executed(bus_tr tr);

 62     `uvm_do_callbacks(bus_driver,bus_driver_cb,trans_executed(this,tr))

 63   endtask

 64

 65   virtual task put(bus_tr t);

 66     uvm_report_info("bus_tr received",t.convert2string());

 67     if (!trans_received(t)) begin

 68       uvm_report_info("bus_tr dropped",

 69           "user callback indicated DROPPED\n");

 70       return;

 71     end

 72     #100;

 73     trans_executed(t);

 74     uvm_report_info("bus_tr executed",{t.convert2string(),"\n"});

 75   endtask

 76

 77 endclass

 78

 79 endpackage // bus_driver_pkg

 80

 81 import uvm_pkg::*;

 82 import bus_driver_pkg::*;

 83

 84 class my_bus_driver_cb extends bus_driver_cb;　　　　//第一个重载

 85

 86   function new(string name="bus_driver_cb_inst");

 87     super.new(name);

 88   endfunction

 89

 90   virtual function bit trans_received(bus_driver driver, bus_tr tr);

 91     static bit drop = 0;

 92     driver.uvm_report_info("trans_received_cb",

 93       {"  bus_driver=",driver.get_full_name()," tr=",tr.convert2string()});

 94     drop = 1 - drop;

 95     return drop;

 96   endfunction

 97

 98   virtual task trans_executed(bus_driver driver, bus_tr tr);

 99     driver.uvm_report_info("trans_executed_cb",

100       {"  bus_driver=",driver.get_full_name()," tr=",tr.convert2string()});

101   endtask

102

103   virtual function string get_type_name();

104     return "my_bus_driver_cb";

105   endfunction

106

107 endclass

108

109 class my_bus_driver_cb2 extends bus_driver_cb;　　　　//第二个

110

111   function new(string name="bus_driver_cb_inst");

112     super.new(name);

113   endfunction

114

115   virtual task trans_executed(bus_driver driver, bus_tr tr);

116     driver.uvm_report_info("trans_executed_cb2",

117       {"  bus_driver=",driver.get_full_name()," tr=",tr.convert2string()});

118   endtask

119

120   virtual function string get_type_name();

121     return "my_bus_driver_cb2";

122   endfunction

123

124 endclass

125

126 module top;

127   import uvm_pkg::*;

128   import bus_driver_pkg::*;

129

130   bus_tr            tr     = new;

131   bus_driver        driver = new("driver");

132   my_bus_driver_cb  cb1    = new("cb1");　　　　// 由于本例结构简单，声明实例一起完成了

133   my_bus_driver_cb2 cb2    = new("cb2");

134

135   initial begin

136     bus_driver_cbs_t::add(driver,cb1);

137     bus_driver_cbs_t::add(driver,cb2);

138     bus_driver_cbs_t::display();

139     for (int i=1; i<=5; i++) begin

140       tr.addr = i;

141       tr.data = 6-i;

142       driver.in.put(tr);

143     end

144     begin

145        uvm_report_server svr = uvm_report_server::get_server();

146        svr.summarize();

147     end

148   end

149

150 endmodule

巴特西

UVM——callback机制应用示例

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