(1) Updated qr interface to include clock and reset needed for internal pipeline registers. (2) Added testbench for the qr module. (3) Added qr simulation target. (4) Added lint support.

3 files changed, 254 insertions, 0 deletions

diff --git a/src/rtl/chacha_core.v b/src/rtl/chacha_core.v
index 5f496a4..d68f783 100644
--- a/src/rtl/chacha_core.v
+++ b/src/rtl/chacha_core.v
@@ -191,6 +191,9 @@ module chacha_core(
   // Instantiation of the qr modules.
   //----------------------------------------------------------------
   chacha_qr qr0(
+                .clk(clk),
+                .reset_n(reset_n),
+
                 .a(qr0_a),
                 .b(qr0_b),
                 .c(qr0_c),
@@ -203,6 +206,9 @@ module chacha_core(
                );
 
   chacha_qr qr1(
+                .clk(clk),
+                .reset_n(reset_n),
+
                 .a(qr1_a),
                 .b(qr1_b),
                 .c(qr1_c),
@@ -215,6 +221,9 @@ module chacha_core(
                );
 
   chacha_qr qr2(
+                .clk(clk),
+                .reset_n(reset_n),
+
                 .a(qr2_a),
                 .b(qr2_b),
                 .c(qr2_c),
@@ -227,6 +236,9 @@ module chacha_core(
                );
 
   chacha_qr qr3(
+                .clk(clk),
+                .reset_n(reset_n),
+
                 .a(qr3_a),
                 .b(qr3_b),
                 .c(qr3_c),
diff --git a/src/rtl/chacha_qr.v b/src/rtl/chacha_qr.v
index 42e644c..e1ddbd8 100644
--- a/src/rtl/chacha_qr.v
+++ b/src/rtl/chacha_qr.v
@@ -40,6 +40,9 @@
 //======================================================================
 
 module chacha_qr(
+                 input wire           clk,
+                 input wire           reset_n,
+
                  input wire [31 : 0]  a,
                  input wire [31 : 0]  b,
                  input wire [31 : 0]  c,
@@ -52,6 +55,13 @@ module chacha_qr(
                 );
 
   //----------------------------------------------------------------
+  // Registers including update variables and write enable.
+  //----------------------------------------------------------------
+  reg [31 : 0] a0_reg;
+  reg [31 : 0] a0_new;
+
+
+  //----------------------------------------------------------------
   // Wires.
   //----------------------------------------------------------------
   reg [31 : 0] internal_a_prim;
@@ -70,6 +80,23 @@ module chacha_qr(
 
 
   //----------------------------------------------------------------
+  // reg_update
+  //----------------------------------------------------------------
+  always @ (posedge clk)
+    begin : reg_update
+      if (!reset_n)
+        begin
+          a0_reg <= 32'h0;
+        end
+
+      else
+        begin
+          a0_reg <= a0_new;
+        end
+    end // reg_update
+
+
+  //----------------------------------------------------------------
   // qr
   //
   // The actual quarterround function.
@@ -93,6 +120,8 @@ module chacha_qr(
       reg [31 : 0] d3;
 
       a0 = a + b;
+      a0_new = a + b;
+
       d0 = d ^ a0;
       d1 = {d0[15 : 0], d0[31 : 16]};
       c0 = c + d1;
diff --git a/src/tb/tb_chacha_qr.v b/src/tb/tb_chacha_qr.v
new file mode 100644
index 0000000..66a790c
--- /dev/null
+++ b/src/tb/tb_chacha_qr.v
@@ -0,0 +1,213 @@
+//======================================================================
+//
+// tb_chacha_qr.v
+// --------------
+// Testbench for the Chacha stream cipher quarerround (QR) module.
+//
+//
+// Author: Joachim Strombergson
+// Copyright (c) 2018, NORDUnet A/S All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// - Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+//
+// - Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in the
+//   documentation and/or other materials provided with the distribution.
+//
+// - Neither the name of the NORDUnet nor the names of its contributors may
+//   be used to endorse or promote products derived from this software
+//   without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+//======================================================================
+
+module tb_chacha_qr();
+
+  //----------------------------------------------------------------
+  // Internal constant and parameter definitions.
+  //----------------------------------------------------------------
+  parameter CLK_HALF_PERIOD = 2;
+  parameter CLK_PERIOD = 2 * CLK_HALF_PERIOD;
+
+
+  //----------------------------------------------------------------
+  // Register and Wire declarations.
+  //----------------------------------------------------------------
+  reg [31 : 0] cycle_ctr;
+  reg [31 : 0] error_ctr;
+  reg [31 : 0] tc_ctr;
+
+  reg tb_clk;
+  reg tb_reset_n;
+
+  reg [31 : 0] a;
+  reg [31 : 0] b;
+  reg [31 : 0] c;
+  reg [31 : 0] d;
+
+  wire [31 : 0] a_prim;
+  wire [31 : 0] b_prim;
+  wire [31 : 0] c_prim;
+  wire [31 : 0] d_prim;
+
+  reg            display_cycle_ctr;
+  reg            display_ctrl_and_ctrs;
+  reg            display_qround;
+  reg            display_state;
+
+
+  //----------------------------------------------------------------
+  // chacha_core device under test.
+  //----------------------------------------------------------------
+  chacha_qr dut(
+                .clk(tb_clk),
+                .reset_n(tb_reset_n),
+
+                .a(a),
+                .b(b),
+                .c(c),
+                .d(d),
+
+                .a_prim(a_prim),
+                .b_prim(b_prim),
+                .c_prim(c_prim),
+                .d_prim(d_prim)
+               );
+
+
+  //----------------------------------------------------------------
+  // clk_gen
+  //
+  // Clock generator process.
+  //----------------------------------------------------------------
+  always
+    begin : clk_gen
+      #CLK_HALF_PERIOD tb_clk = !tb_clk;
+    end // clk_gen
+
+
+  //--------------------------------------------------------------------
+  // dut_monitor
+  //
+  // Monitor that displays different types of information
+  // every cycle depending on what flags test cases enable.
+  //
+  // The monitor includes a cycle counter for the testbench.
+  //--------------------------------------------------------------------
+  always @ (posedge tb_clk)
+    begin : dut_monitor
+      cycle_ctr = cycle_ctr + 1;
+
+      $display("cycle = %08x:", cycle_ctr);
+      $display("");
+
+      $display("a      = %08x, b      = %08x, c      = %08x, d      = %08x",
+               a, b, c, d);
+      $display("a_prim = %08x, b_prim = %08x, c_prim = %08x, d_prim = %08x",
+               a_prim, b_prim, c_prim, d_prim);
+      $display("");
+    end // dut_monitor
+
+
+  //----------------------------------------------------------------
+  // cycle_reset()
+  //
+  // Cycles the reset signal on the dut.
+  //----------------------------------------------------------------
+  task cycle_reset;
+    begin
+      tb_reset_n = 0;
+      #(CLK_PERIOD);
+
+      @(negedge tb_clk)
+
+      tb_reset_n = 1;
+      #(CLK_PERIOD);
+    end
+  endtask // cycle_reset
+
+
+  //----------------------------------------------------------------
+  // init_sim()
+  //
+  // Set the input to the DUT to defined values.
+  //----------------------------------------------------------------
+  task init_sim;
+    begin
+      cycle_ctr         = 0;
+      tb_clk            = 0;
+      tb_reset_n        = 0;
+      error_ctr         = 0;
+    end
+  endtask // init_dut
+
+
+  //----------------------------------------------------------------
+  // qr_tests()
+  //
+  // Run some simple test on the qr logic.
+  // Note: Not self testing. No expected value used.
+  //----------------------------------------------------------------
+  task qr_tests;
+    begin
+      $display("*** Test of Quarterround:");
+      $display("");
+      a = 32'h11223344;
+      b = 32'h11223344;
+      c = 32'h11223344;
+      d = 32'h11223344;
+
+      #(CLK_PERIOD * 10);
+
+      a = 32'h55555555;
+      b = 32'h55555555;
+      c = 32'h55555555;
+      d = 32'h55555555;
+
+      #(CLK_PERIOD * 10);
+    end
+  endtask // qr_tests
+
+
+  //----------------------------------------------------------------
+  // chacha_qr_test
+  //
+  // The main test functionality.
+  //----------------------------------------------------------------
+  initial
+    begin : chacha_qr_test
+      $display("   -- Testbench for chacha qr started --");
+      $display("");
+
+      init_sim();
+      #(CLK_PERIOD * 10);
+      cycle_reset();
+      #(CLK_PERIOD * 10);
+
+      qr_tests();
+
+      // Finish in style.
+      $display("   -- Testbench for chacha qr completed --");
+      $finish;
+    end // chacha_core_test
+
+endmodule // tb_chacha_qr
+
+//======================================================================
+// EOF tb_chacha_qr.v
+//======================================================================