[Cryptech-Commits] [core/trng] 02/02: More debug fixes. We add one extra wait cycle to allow the mixer to detect that we want more seed.

[git at cryptech.is]

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joachim at secworks.se pushed a commit to branch master
in repository core/trng.

commit f2a4ea70dbee4c50b10045636dd91c3ef47386f1
Author: Joachim Strömbergson <joachim at secworks.se>
Date:   Tue Sep 16 17:21:09 2014 +0200

    More debug fixes. We add one extra wait cycle to allow the mixer to detect that we want more seed.
---
 src/rtl/trng_csprng.v | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/src/rtl/trng_csprng.v b/src/rtl/trng_csprng.v
index 4d472d2..1bdc737 100644
--- a/src/rtl/trng_csprng.v
+++ b/src/rtl/trng_csprng.v
@@ -42,18 +42,18 @@ module trng_csprng(
                    input wire           reset_n,
 
                    // Control, config and status.
+                   input wire           enable,
                    input                debug_mode,
                    input wire [4 : 0]   num_rounds,
                    input wire [63 : 0]  num_blocks,
                    input wire           seed,
-                   input wire           enable,
                    output wire          more_seed,
                    output wire          ready,
                    output wire          error,
 
                    // Seed input
-                   input wire           seed_syn,
                    input [511 : 0]      seed_data,
+                   input wire           seed_syn,
                    output wire          seed_ack,
 
                    // Random data output
@@ -71,12 +71,13 @@ module trng_csprng(
 
   parameter CTRL_IDLE      = 4'h0;
   parameter CTRL_SEED0     = 4'h1;
-  parameter CTRL_SEED1     = 4'h2;
-  parameter CTRL_INIT0     = 4'h3;
-  parameter CTRL_INIT1     = 4'h4;
-  parameter CTRL_NEXT0     = 4'h5;
-  parameter CTRL_NEXT1     = 4'h6;
-  parameter CTRL_MORE      = 4'h7;
+  parameter CTRL_NSYN      = 4'h2;
+  parameter CTRL_SEED1     = 4'h3;
+  parameter CTRL_INIT0     = 4'h4;
+  parameter CTRL_INIT1     = 4'h5;
+  parameter CTRL_NEXT0     = 4'h6;
+  parameter CTRL_NEXT1     = 4'h7;
+  parameter CTRL_MORE      = 4'h8;
   parameter CTRL_CANCEL    = 4'hf;
 
 
@@ -133,6 +134,7 @@ module trng_csprng(
 
   wire [511 : 0] cipher_data_out;
   wire           cipher_data_out_valid;
+  wire           cipher_ready;
 
   reg            discard_outputs;
 
@@ -354,10 +356,24 @@ module trng_csprng(
               end
             else if (seed_syn)
               begin
-                more_seed_new    = 1;
                 seed_ack_new     = 1;
                 cipher_block_new = seed_data;
                 cipher_block_we  = 1;
+                csprng_ctrl_new  = CTRL_NSYN;
+                csprng_ctrl_we   = 1;
+              end
+          end
+
+        CTRL_NSYN:
+          begin
+            if ((!enable) || (seed))
+              begin
+                csprng_ctrl_new = CTRL_CANCEL;
+                csprng_ctrl_we  = 1;
+              end
+            else
+              begin
+                more_seed_new    = 1;
                 csprng_ctrl_new  = CTRL_SEED1;
                 csprng_ctrl_we   = 1;
               end