Adding test case that verifies that SW can keep a key alive by reading status register.

1 files changed, 52 insertions, 28 deletions

diff --git a/src/tb/tb_keywrap.v b/src/tb/tb_keywrap.v
index 75e01e3..ef266ab 100644
--- a/src/tb/tb_keywrap.v
+++ b/src/tb/tb_keywrap.v
@@ -1259,7 +1259,7 @@ module tb_keywrap();
       $display("Status of timeout counter: 0x%04x",
                dut.core.key_timeout_ctr_reg);
       // Display contents in key expansion register 2 again.
-      $display("Contents in key_mem[2] after init: 0x%016x",
+      $display("Contents in key_mem[2] after timeout: 0x%016x",
                dut.core.aes.keymem.key_mem[2]);
 
       if (dut.core.aes.keymem.key_mem[2] != 128'h62636363626363636263636362636363)
@@ -1305,16 +1305,6 @@ module tb_keywrap();
       read_word(ADDR_STATUS);
       $display("Status register: 0x%032b", read_data);
 
-      // Set the key timeout to 256 cycles.
-      write_word(ADDR_TIMEOUT, 32'hdeadbeef);
-      read_word(ADDR_TIMEOUT);
-      if (read_data != 32'hdeadbeef)
-        $display("Error. Timout value = 0x%04x, expected 0xdeadbeef", read_data);
-
-      // Display contents in key expansion register 2.
-      $display("Contents of the key_mem[2] before init: 0x%016x",
-               dut.core.aes.keymem.key_mem[2]);
-
       // Initialize the AES engine (to expand the key).
       // Wait for init to complete.
       // Note, not actually needed to wait. We can write R data during init.
@@ -1332,7 +1322,12 @@ module tb_keywrap();
       read_word(ADDR_STATUS);
       $display("Status register: 0b%032b", read_data);
 
+      // Set the key timeout to 256 cycles.
+      $display("Setting timout to 16 cycles and then we keep it alive.");
+      write_word(ADDR_TIMEOUT, 32'h00000010);
+
       // Display the timeout counter a few times.
+      // And then read status. Which should trigger reset of timout.
       $display("Contents of timeout counter: 0x%04x",
                dut.core.key_timeout_ctr_reg);
       #(2 * CLK_PERIOD);
@@ -1344,33 +1339,61 @@ module tb_keywrap();
       #(2 * CLK_PERIOD);
       $display("Contents of timeout counter: 0x%04x",
                dut.core.key_timeout_ctr_reg);
-      #(2 * CLK_PERIOD);
-
       read_word(ADDR_STATUS);
       $display("Status register: 0x%032b", read_data);
 
-      // Display contents in one of the key expansion registers
-      $display("Contents of the key_mem[2]: 0x%016x",
-               dut.core.aes.keymem.key_mem[2]);
-      // Display contents in one of the key expansion registers
-      $display("Contents of the key_mem[2]: 0x%016x",
-               dut.core.aes.keymem.key_mem[2]);
-      // Display contents in one of the key expansion registers
+      // Display the timeout counter a few times.
+      // And then read status. Which should trigger reset of timout.
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      read_word(ADDR_STATUS);
+      $display("Status register: 0x%032b", read_data);
       $display("Contents of the key_mem[2]: 0x%016x",
                dut.core.aes.keymem.key_mem[2]);
 
-      #(40 * CLK_PERIOD);
-
-      // Set the key timeout to 16 cycles.
-      // Read status to perform ping.
-      write_word(ADDR_TIMEOUT, 32'h00000010);
+      // Display the timeout counter a few times.
+      // And then read status. Which should trigger reset of timout.
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
+      #(2 * CLK_PERIOD);
+      $display("Contents of timeout counter: 0x%04x",
+               dut.core.key_timeout_ctr_reg);
       read_word(ADDR_STATUS);
-      #(400 * CLK_PERIOD);
+      $display("Status register: 0x%032b", read_data);
 
 
+      $display("We now allow the timer to expire");
+      #(40 * CLK_PERIOD);
       read_word(ADDR_STATUS);
       $display("Status register: 0x%032b", read_data);
-
+      $display("Contents of the key_mem[2]: 0x%016x",
+               dut.core.aes.keymem.key_mem[2]);
 
       $display("** TC test_zeroise2 END.\n");
     end
@@ -1508,8 +1531,9 @@ module tb_keywrap();
 
 //      test_big_wrap_256();
 
+      reset_dut();
       test_zeroise1();
-//      test_zeroise2();
+      test_zeroise2();
 //      test_zeroise3();
 
       display_test_results();