//======================================================================
//
// aes.v
// --------
// Top level wrapper for the AES block cipher core.
//
//
// Author: Joachim Strombergson
// Copyright (c) 2014, 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 aes(
// Clock and reset.
input wire clk,
input wire reset_n,
// Control.
input wire cs,
input wire we,
// Data ports.
input wire [7 : 0] address,
input wire [31 : 0] write_data,
output wire [31 : 0] read_data,
output wire error
);
//----------------------------------------------------------------
// Internal constant and parameter definitions.
//----------------------------------------------------------------
localparam ADDR_NAME0 = 8'h00;
localparam ADDR_NAME1 = 8'h01;
localparam ADDR_VERSION = 8'h02;
localparam ADDR_CTRL = 8'h08;
localparam CTRL_INIT_BIT = 0;
localparam CTRL_NEXT_BIT = 1;
localparam ADDR_STATUS = 8'h09;
localparam STATUS_READY_BIT = 0;
localparam STATUS_VALID_BIT = 1;
localparam ADDR_CONFIG = 8'h0a;
localparam CTRL_ENCDEC_BIT = 0;
localparam CTRL_KEYLEN_BIT = 1;
localparam ADDR_KEY0 = 8'h10;
localparam ADDR_KEY7 = 8'h17;
localparam ADDR_BLOCK0 = 8'h20;
localparam ADDR_BLOCK3 = 8'h23;
localparam ADDR_RESULT0 = 8'h30;
localparam ADDR_RESULT1 = 8'h31;
localparam ADDR_RESULT2 = 8'h32;
localparam ADDR_RESULT3 = 8'h33;
localparam CORE_NAME0 = 32'h61657320; // "aes "
localparam CORE_NAME1 = 32'h20202020; // " "
localparam CORE_VERSION = 32'h302e3730; // "0.70"
//----------------------------------------------------------------
// Registers including update variables and write enable.
//----------------------------------------------------------------
reg init_reg;
reg init_new;
reg next_reg;
reg next_new;
reg encdec_reg;
reg keylen_reg;
reg config_we;
reg [31 : 0] block_reg [0 : 3];
reg block_we;
reg [31 : 0] key_reg [0 : 7];
reg key_we;
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
reg [31 : 0] tmp_read_data;
reg tmp_error;
wire core_encdec;
wire core_init;
wire core_next;
wire core_ready;
wire [255 : 0] core_key;
wire core_keylen;
wire [127 : 0] core_block;
wire [127 : 0] core_result;
wire core_valid;
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
assign read_data = tmp_read_data;
assign error = tmp_error;
assign core_key = {key_reg[0], key_reg[1], key_reg[2], key_reg[3],
key_reg[4], key_reg[5], key_reg[6], key_reg[7]};
assign core_block = {block_reg[0], block_reg[1],
block_reg[2], block_reg[3]};
assign core_init = init_reg;
assign core_next = next_reg;
assign core_encdec = encdec_reg;
assign core_keylen = keylen_reg;
//----------------------------------------------------------------
// core instantiation.
//----------------------------------------------------------------
aes_core core(
.clk(clk),
.reset_n(reset_n),
.encdec(core_encdec),
.init(core_init),
.next(core_next),
.ready(core_ready),
.key(core_key),
.keylen(core_keylen),
.block(core_block),
.result(core_result),
.result_valid(core_valid)
);
//----------------------------------------------------------------
// reg_update
// Update functionality for all registers in the core.
// All registers are positive edge triggered with asynchronous
// active low reset.
//----------------------------------------------------------------
always @ (posedge clk or negedge reset_n)
begin : reg_update
integer i;
if (!reset_n)
begin
for (i = 0 ; i < 4 ; i = i + 1)
block_reg[i] <= 32'h0;
for (i = 0 ; i < 8 ; i = i + 1)
key_reg[i] <= 32'h0;
init_reg <= 1'b0;
next_reg <= 1'b0;
encdec_reg <= 1'b0;
keylen_reg <= 1'b0;
end
else
begin
init_reg <= init_new;
next_reg <= next_new;
if (config_we)
begin
encdec_reg <= write_data[CTRL_ENCDEC_BIT];
keylen_reg <= write_data[CTRL_KEYLEN_BIT];
end
if (key_we)
key_reg[address[2 : 0]] <= write_data;
if (block_we)
block_reg[address[1 : 0]] <= write_data;
end
end // reg_update
//----------------------------------------------------------------
// api
//
// The interface command decoding logic.
//----------------------------------------------------------------
always @*
begin : api
init_new = 1'b0;
next_new = 1'b0;
config_we = 1'b0;
key_we = 1'b0;
block_we = 1'b0;
tmp_read_data = 32'h0;
tmp_error = 1'b0;
if (cs)
begin
if (we)
begin
if (core_ready)
begin
if (address == ADDR_CTRL)
begin
init_new = write_data[CTRL_INIT_BIT];
next_new = write_data[CTRL_NEXT_BIT];
end
if (address == ADDR_CONFIG)
config_we = 1'b1;
if ((address >= ADDR_KEY0) && (address <= ADDR_KEY7))
key_we = 1'b1;
if ((address >= ADDR_BLOCK0) && (address <= ADDR_BLOCK3))
block_we = 1'b1;
end
end // if (we)
else
begin
case (address)
ADDR_NAME0: tmp_read_data = CORE_NAME0;
ADDR_NAME1: tmp_read_data = CORE_NAME1;
ADDR_VERSION: tmp_read_data = CORE_VERSION;
ADDR_CTRL: tmp_read_data = {28'h0, keylen_reg, encdec_reg, next_reg, init_reg};
ADDR_STATUS: tmp_read_data = {30'h0, core_valid, core_ready};
default:
begin
end
endcase // case (address)
if ((address >= ADDR_RESULT0) && (address <= ADDR_RESULT3))
if (core_ready)
tmp_read_data = core_result[(3 - (address - ADDR_RESULT0)) * 32 +: 32];
end
end
end // addr_decoder
endmodule // aes
//======================================================================
// EOF aes.v
//======================================================================
