Adding test case for verifying reseed functionality in csprng.

1 files changed, 42 insertions, 0 deletions

diff --git a/src/tb/tb_csprng.v b/src/tb/tb_csprng.v
index 0404b56..7f7823e 100644
--- a/src/tb/tb_csprng.v
+++ b/src/tb/tb_csprng.v
@@ -353,6 +353,7 @@ module tb_csprng();
       tb_seed_data = {8{64'haaaaaaaa55555555}};
       tb_seed_syn  = 1'b1;
 
+      // Start pulling data.
       tb_cs        = 1'b1;
       tb_we        = 1'b0;
       tb_address   = ADDR_RND_DATA;
@@ -365,6 +366,46 @@ module tb_csprng();
 
 
   //----------------------------------------------------------------
+  // tc2_reseed_csprng()
+  //
+  // TC2: Test that the CSPRNG is reseeded as expected.
+  // We set the max block size to a small value and pull data.
+  //----------------------------------------------------------------
+  task tc2_reseed_csprng();
+    begin
+      tc_ctr = tc_ctr + 1;
+
+      $display("*** TC2: Test reseed of CSPRNG started.");
+
+      tb_seed_data = {8{64'h0102030405060708}};
+      tb_seed_syn  = 1'b1;
+
+      // Set the max block size to a low value
+      tb_cs        = 1'b1;
+      tb_we        = 1'b1;
+      tb_address   = ADDR_NUM_BLOCKS_HIGH;
+      tb_write_data   = 32'h00000000;
+      #(CLK_PERIOD);
+      tb_address   = ADDR_NUM_BLOCKS_LOW;
+      tb_write_data   = 32'h00000001;
+      #(CLK_PERIOD);
+      tb_cs        = 1'b0;
+      tb_we        = 1'b0;
+      #(CLK_PERIOD);
+
+      // Start pulling data.
+      tb_cs        = 1'b1;
+      tb_we        = 1'b0;
+      tb_address   = ADDR_RND_DATA;
+
+      #(200 * CLK_PERIOD);
+
+      $display("*** TC2 done..");
+    end
+  endtask // tc2_reseed_csprng
+
+
+  //----------------------------------------------------------------
   // csprng_test
   //
   // The main test functionality.
@@ -382,6 +423,7 @@ module tb_csprng();
       dump_dut_state();
 
       tc1_init_csprng();
+      tc2_reseed_csprng();
 
       display_test_results();