Adding support for automatic A-value and RLEN calculation. Adding support for checking that unwrapped data is valid.auto_magic

2 files changed, 49 insertions, 32 deletions

diff --git a/src/rtl/keywrap.v b/src/rtl/keywrap.v
index f8fcbd7..2d241a9 100644
--- a/src/rtl/keywrap.v
+++ b/src/rtl/keywrap.v
@@ -4,17 +4,6 @@
 // --------
 // Top level wrapper for the KEY WRAP core.
 //
-// Since $clog2() is not supported by all tools, and constant
-// functions are not supported by some other tools we need to
-// do the size to number of bits calculation by hand.
-// 8192 bytes = 2048 32 bit words. This requires 11 bits.
-// We need additional space for control and status words. But
-// since we have filled the address space, we need another MSB
-// in the address. Thus ADDR_BITS = 12 bits.
-//
-// 0x000 - 0x7ff are for control and status.
-// 0x800 - 0xfff are for data storage
-//
 //
 // Author: Joachim Strombergson
 // Copyright (c) 2018, NORDUnet A/S
@@ -81,7 +70,7 @@ module keywrap #(parameter ADDR_BITS = 13)
   localparam CTRL_ENCDEC_BIT  = 0;
   localparam CTRL_KEYLEN_BIT  = 1;
 
-  localparam ADDR_RLEN        = 8'h0c;
+  localparam ADDR_LENGTH      = 8'h0c;
   localparam ADDR_A0          = 8'h0e;
   localparam ADDR_A1          = 8'h0f;
 
@@ -96,10 +85,10 @@ module keywrap #(parameter ADDR_BITS = 13)
 
   localparam CORE_NAME0       = 32'h6b657920; // "key "
   localparam CORE_NAME1       = 32'h77726170; // "wrap"
-  localparam CORE_VERSION     = 32'h302e3830; // "0.80"
+  localparam CORE_VERSION     = 32'h312e3031; // "1.01"
 
   localparam MEM_BITS         = ADDR_BITS - 1;
-  localparam RLEN_BITS        = ADDR_BITS - 2;
+  localparam LEN_BITS         = MEM_BITS + 2;
   localparam PAD              = ADDR_BITS - 8;
 
 
@@ -116,8 +105,8 @@ module keywrap #(parameter ADDR_BITS = 13)
   reg keylen_reg;
   reg config_we;
 
-  reg [(RLEN_BITS - 1) : 0] rlen_reg;
-  reg                       rlen_we;
+  reg [(LEN_BITS - 1) : 0] length_reg;
+  reg                      length_we;
 
   reg [31 : 0] a0_reg;
   reg          a0_we;
@@ -180,7 +169,7 @@ module keywrap #(parameter ADDR_BITS = 13)
                     .ready(core_ready),
                     .valid(core_valid),
 
-                    .rlen(rlen_reg),
+                    .length(length_reg),
 
                     .key(core_key),
                     .keylen(keylen_reg),
@@ -211,7 +200,7 @@ module keywrap #(parameter ADDR_BITS = 13)
           next_reg         <= 1'h0;
           encdec_reg       <= 1'h0;
           keylen_reg       <= 1'h0;
-          rlen_reg         <= {RLEN_BITS{1'h0}};
+          length_reg       <= {LEN_BITS{1'h0}};
           valid_reg        <= 1'h0;
           ready_reg        <= 1'h0;
           a0_reg           <= 32'h0;
@@ -232,8 +221,8 @@ module keywrap #(parameter ADDR_BITS = 13)
               keylen_reg <= write_data[CTRL_KEYLEN_BIT];
             end
 
-          if (rlen_we)
-            rlen_reg <= write_data[12 : 0];
+          if (length_we)
+            length_reg <= write_data[(LEN_BITS - 1) : 0];
 
           if (a0_we)
             a0_reg <= write_data;
@@ -257,7 +246,7 @@ module keywrap #(parameter ADDR_BITS = 13)
       init_new         = 1'h0;
       next_new         = 1'h0;
       config_we        = 1'h0;
-      rlen_we          = 1'h0;
+      length_we        = 1'h0;
       key_we           = 1'h0;
       core_api_we      = 1'h0;
       a0_we            = 1'h0;
@@ -285,8 +274,8 @@ module keywrap #(parameter ADDR_BITS = 13)
               if (address == {{PAD{1'h0}}, ADDR_CONFIG})
                 config_we = 1'h1;
 
-              if (address == {{PAD{1'h0}}, ADDR_RLEN})
-                rlen_we = 1'h1;
+              if (address == {{PAD{1'h0}}, ADDR_LENGTH})
+                length_we = 1'h1;
 
               if (address == {{PAD{1'h0}}, ADDR_A0})
                 a0_we = 1'h1;
@@ -319,8 +308,8 @@ module keywrap #(parameter ADDR_BITS = 13)
               if (address == {{PAD{1'h0}}, ADDR_STATUS})
                 api_rd_delay_new = {30'h0, valid_reg, ready_reg};
 
-              if (address == {{PAD{1'h0}}, ADDR_RLEN})
-                api_rd_delay_new = {19'h0, rlen_reg};
+              if (address == {{PAD{1'h0}}, ADDR_LENGTH})
+                api_rd_delay_new = {{(32 - LEN_BITS){1'h0}}, length_reg};
 
               if (address == {{PAD{1'h0}}, ADDR_A0})
                 api_rd_delay_new = core_a_result[63 : 32];
diff --git a/src/rtl/keywrap_core.v b/src/rtl/keywrap_core.v
index d1e63b0..469a238 100644
--- a/src/rtl/keywrap_core.v
+++ b/src/rtl/keywrap_core.v
@@ -52,7 +52,7 @@ module keywrap_core #(parameter MEM_BITS = 11)
                      output wire                      ready,
                      output wire                      valid,
 
-                     input wire [(MEM_BITS - 2) : 0]  rlen,
+                     input wire [(LEN_BITS - 1) : 0]  length,
 
                      input wire [255 : 0]             key,
                      input wire                       keylen,
@@ -84,6 +84,10 @@ module keywrap_core #(parameter MEM_BITS = 11)
   localparam CTRL_NEXT_UCHECK   = 4'h9;
   localparam CTRL_NEXT_FINALIZE = 4'ha;
 
+  localparam LEN_BITS = MEM_BITS + 2;
+
+  localparam AIV = 32'ha65959a6;
+
 
   //----------------------------------------------------------------
   // Registers and memories including control signals.
@@ -134,6 +138,8 @@ module keywrap_core #(parameter MEM_BITS = 11)
 
   reg            update_state;
 
+  reg [(MEM_BITS - 1) : 0] rlen;
+
   reg                      core_we;
   reg [(MEM_BITS - 2) : 0] core_addr;
   reg [63 : 0]             core_wr_data;
@@ -238,7 +244,13 @@ module keywrap_core #(parameter MEM_BITS = 11)
       core_addr = block_ctr_reg;
       core_we   = 1'h0;
 
-      xor_val = (rlen * iteration_ctr_reg) + {51'h0, (block_ctr_reg + 1'h1)};
+      // Calculate the correct number of blocks including padding.
+      if (length[1 : 0] === 2'h0)
+        rlen = length[(LEN_BITS - 1) : 3];
+      else
+        rlen = length[(LEN_BITS - 2) : 3] + 1'b1;
+
+      xor_val = (rlen * iteration_ctr_reg) + {52'h0, (block_ctr_reg + 1'h1)};
 
       if (encdec)
         aes_block = {a_reg, core_rd_data};
@@ -249,8 +261,11 @@ module keywrap_core #(parameter MEM_BITS = 11)
 
       if (init_a)
         begin
-          a_new = a_init;
           a_we  = 1'h1;
+          if (encdec)
+            a_new = {AIV, {{(32 - (MEM_BITS + 2)){1'b0}}, length}};
+          else
+            a_new = a_init;
         end
 
       if (update_state)
@@ -510,10 +525,23 @@ module keywrap_core #(parameter MEM_BITS = 11)
 
         CTRL_NEXT_FINALIZE:
           begin
-            ready_new             = 1'h1;
-            ready_we              = 1'h1;
-            valid_new             = 1'h1;
-            valid_we              = 1'h1;
+            ready_new = 1'h1;
+            ready_we  = 1'h1;
+
+            if (encdec)
+              begin
+                valid_new = 1'h1;
+                valid_we  = 1'h1;
+              end
+            else
+              begin
+                if (a_reg[63 : 32] == AIV)
+                  begin
+                    valid_new = 1'h1;
+                    valid_we  = 1'h1;
+                  end
+              end
+
             keywrap_core_ctrl_new = CTRL_IDLE;
             keywrap_core_ctrl_we  = 1'h1;
           end