(1) Added a cipher block statistics counter. (2) Cleaned up the csprng code and connected discard for fast restart of trng. (3) Added addresses for allowing API to write a known seed to allow test mode. (3) Fixed a number of minor issues during linting. (4) Fixed the csprng testbench to actually generate data as well as displaying the block stat counter.

3 files changed, 50 insertions, 27 deletions

diff --git a/src/tb/fake_modules/avalanche_entropy.v b/src/tb/fake_modules/avalanche_entropy.v
index 857926c..2caf743 100644
--- a/src/tb/fake_modules/avalanche_entropy.v
+++ b/src/tb/fake_modules/avalanche_entropy.v
@@ -80,9 +80,9 @@ module avalanche_entropy(
                       .clk(clk),
                       .reset_n(reset_n),
 
-                      .enable(1),
+                      .enable(1'b1),
 
-                      .raw_entropy(noise),
+                      .raw_entropy(),
                       .stats(),
 
                       .enabled(entropy_enabled),
diff --git a/src/tb/fake_modules/rosc_entropy.v b/src/tb/fake_modules/rosc_entropy.v
index b66bd90..add8b7a 100644
--- a/src/tb/fake_modules/rosc_entropy.v
+++ b/src/tb/fake_modules/rosc_entropy.v
@@ -41,8 +41,6 @@ module rosc_entropy(
                     input wire           clk,
                     input wire           reset_n,
 
-                    input wire           noise,
-
                     input wire           cs,
                     input wire           we,
                     input wire  [7 : 0]  address,
@@ -80,9 +78,9 @@ module rosc_entropy(
                       .clk(clk),
                       .reset_n(reset_n),
 
-                      .enable(1),
+                      .enable(1'b1),
 
-                      .raw_entropy(noise),
+                      .raw_entropy(),
                       .stats(),
 
                       .enabled(entropy_enabled),
diff --git a/src/tb/tb_csprng.v b/src/tb/tb_csprng.v
index f860258..0404b56 100644
--- a/src/tb/tb_csprng.v
+++ b/src/tb/tb_csprng.v
@@ -55,6 +55,25 @@ module tb_csprng();
   parameter CLK_HALF_PERIOD = 1;
   parameter CLK_PERIOD      = 2 * CLK_HALF_PERIOD;
 
+  localparam ADDR_NAME0            = 8'h00;
+  localparam ADDR_NAME1            = 8'h01;
+  localparam ADDR_VERSION          = 8'h02;
+
+  localparam ADDR_CTRL             = 8'h10;
+  localparam CTRL_ENABLE_BIT       = 0;
+  localparam CTRL_SEED_BIT         = 1;
+
+  localparam ADDR_STATUS           = 8'h11;
+  localparam STATUS_RND_VALID_BIT  = 0;
+
+  localparam ADDR_STAT_BLOCKS_LOW  = 8'h14;
+  localparam ADDR_STAT_BLOCKS_HIGH = 8'h15;
+
+  localparam ADDR_RND_DATA         = 8'h20;
+
+  localparam ADDR_NUM_ROUNDS       = 8'h40;
+  localparam ADDR_NUM_BLOCKS_LOW   = 8'h41;
+  localparam ADDR_NUM_BLOCKS_HIGH  = 8'h42;
 
   //----------------------------------------------------------------
   // Register and Wire declarations.
@@ -166,17 +185,19 @@ module tb_csprng();
       $display("test_mode = 0x%01x, seed = 0x%01x, enable = 0x%01x",
                dut.test_mode, dut.seed_reg, dut.enable_reg);
       $display("num_rounds = 0x%02x, num_blocks = 0x%016x",
-               dut.num_rounds_reg, dut.num_blocks);
+               dut.num_rounds_reg, {dut.num_blocks_high_reg,
+                                    dut.num_blocks_low_reg});
       $display("seed_syn = 0x%01x, seed_ack = 0x%01x, seed_data = 0x%064x",
                dut.seed_syn, dut.seed_ack, dut.seed_data);
       $display("");
 
       $display("Internal states:");
-      $display("cipher_key   = 0x%032x", dut.cipher_key_reg);
-      $display("cipher_iv    = 0x%08x, cipher_ctr = 0x%08x",
+      $display("cipher_key    = 0x%032x", dut.cipher_key_reg);
+      $display("cipher_iv     = 0x%08x, cipher_ctr = 0x%08x",
                dut.cipher_iv_reg, dut.cipher_ctr_reg);
-      $display("cipher_block = 0x%064x", dut.cipher_block_reg);
-      $display("csprng_ctrl  = 0x%02x", dut.csprng_ctrl_reg);
+      $display("cipher_block  = 0x%064x", dut.cipher_block_reg);
+      $display("csprng_blocks = 0x%016x", dut.block_stat_ctr_reg);
+      $display("csprng_ctrl   = 0x%02x", dut.csprng_ctrl_reg);
       $display("");
 
       $display("Cipher states:");
@@ -192,7 +213,7 @@ module tb_csprng();
 
       $display("Outputs:");
       $display("rnd_syn = 0x%01x, rnd_ack = 0x%01x, rnd_data = 0x%08x",
-               dut.rnd_syn, dut.rnd_ack, dut.rnd_data);
+               dut.rnd_syn, dut.rnd_ack, tb_read_data);
       $display("");
     end
   endtask // dump_dut_state
@@ -203,7 +224,7 @@ module tb_csprng();
   //
   // Write the given word to the DUT using the DUT interface.
   //----------------------------------------------------------------
-  task write_word(input [11 : 0]  address,
+  task write_word(input [11 : 0] address,
                   input [31 : 0] word);
     begin
       if (DEBUG)
@@ -317,25 +338,30 @@ module tb_csprng();
 
 
   //----------------------------------------------------------------
-  // tc1_test_init_cipher()
+  // tc1_init_csprng()
   //
   // TC1: Test that the DUT automatically starts initialize when
-  // enable is set.
+  // enable is set. We also starts pulling random data from the
+  // csprng to see that it actually emits data as expected.
   //----------------------------------------------------------------
-  task tc1_test_init_cipher();
+  task tc1_init_csprng();
     begin
-      $display("*** TC1: Test automatic init of cipher started.");
-      // tb_num_blocks = 64'h0000000000000004;
-      tb_seed_data  = {8{64'haaaaaaaa55555555}};
-      // tb_num_rounds = 5'h08;
-      tb_rnd_ack    = 1;
+      tc_ctr = tc_ctr + 1;
+
+      $display("*** TC1: Test automatic init of csprng started.");
+
+      tb_seed_data = {8{64'haaaaaaaa55555555}};
+      tb_seed_syn  = 1'b1;
 
-      #(2000 * CLK_PERIOD);
+      tb_cs        = 1'b1;
+      tb_we        = 1'b0;
+      tb_address   = ADDR_RND_DATA;
 
-      $display("*** TC1: Test automatic init of cipher done.");
+      #(200 * CLK_PERIOD);
 
+      $display("*** TC1: Test automatic init of csprng done.");
     end
-  endtask // tc1_test_init_cipher
+  endtask // tc1_init_csprng
 
 
   //----------------------------------------------------------------
@@ -355,13 +381,12 @@ module tb_csprng();
       reset_dut();
       dump_dut_state();
 
-      // Test code goes here.
-      tc1_test_init_cipher();
+      tc1_init_csprng();
 
       display_test_results();
 
       $display("");
-      $display("*** CSPRNG simulation done. ***");
+      $display("*** csprng simulation done. ***");
       $finish;
     end // csprng_test
 endmodule // tb_csprng