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//////////////////////////////////////////////////////////////////

////

////

////    AES CORE BLOCK

////

////

////

//// This file is part of the APB to I2C project

////

//// http://www.opencores.org/cores/apbi2c/

////

////

////

//// Description

////

//// Implementation of APB IP core according to

////

//// aes128_spec IP core specification document.

////

////

////

//// To Do: Things are right here but always all block can suffer changes

////

////

////

////

////

//// Author(s): - Felipe Fernandes Da Costa, fefe2560@gmail.com

////              Julio Cesar 

////

///////////////////////////////////////////////////////////////// 

////

////

//// Copyright (C) 2009 Authors and OPENCORES.ORG

////

////

////

//// This source file may be used and distributed without

////

//// restriction provided that this copyright statement is not

////

//// removed from the file and that any derivative work contains

//// the original copyright notice and the associated disclaimer.

////

////

//// This source file is free software; you can redistribute it

////

//// and/or modify it under the terms of the GNU Lesser General

////

//// Public License as published by the Free Software Foundation;

//// either version 2.1 of the License, or (at your option) any

////

//// later version.

////

////

////

//// This source is distributed in the hope that it will be

////

//// useful, but WITHOUT ANY WARRANTY; without even the implied

////

//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR

////

//// PURPOSE. See the GNU Lesser General Public License for more

//// details.

////

////

////

//// You should have received a copy of the GNU Lesser General

////

//// Public License along with this source; if not, download it

////

//// from http://www.opencores.org/lgpl.shtml

////

////

///////////////////////////////////////////////////////////////////

module datapath

(

        // OUTPUTS

        output [31:0] col_bus,

        output [31:0] key_bus,

        output [31:0] iv_bus,

        output end_aes,

        // INPUTS

        input [31:0] bus_in,

        input [ 1:0] data_type,

        input [ 1:0] rk_sel,

        input [ 1:0] key_out_sel,

        input [ 3:0] round,

        input [ 2:0] sbox_sel,

        input [ 3:0] iv_en,

        input [ 3:0] iv_sel_rd,

        input [ 3:0] col_en_host,

        input [ 3:0] col_en_cnt_unit,

        input [ 3:0] key_host_en,

        input [ 3:0] key_en,

        input [ 1:0] key_sel_rd,

        input [ 1:0] col_sel,

        input [ 1:0] col_sel_host,

        input end_comp,

        input key_sel,

        input key_init,

        input bypass_rk,

        input bypass_key_en,

        input first_block,

        input last_round,

        input iv_cnt_en,

        input iv_cnt_sel,

        input enc_dec,

        input mode_ctr,

        input mode_cbc,

        input key_gen,

        input key_derivation_en,

        input rst_n,

        input clk

);

//`include "include/control_unit_params.vh"

//=============================================================================

// SBOX SEL

//=============================================================================

localparam COL_0 = 3'b000;

localparam COL_1 = 3'b001;

localparam COL_2 = 3'b010;

localparam COL_3 = 3'b011;

localparam G_FUNCTION = 3'b100;

//=============================================================================

// RK_SEL

//=============================================================================

localparam COL        = 2'b00;

localparam MIXCOL_IN  = 2'b01;

localparam MIXCOL_OUT = 2'b10;

//=============================================================================

// KEY_OUT_SEL

//=============================================================================

localparam KEY_0 = 2'b00;

localparam KEY_1 = 2'b01;

localparam KEY_2 = 2'b10;

localparam KEY_3 = 2'b11;

//=============================================================================

// COL_SEL

//=============================================================================

localparam SHIFT_ROWS = 2'b00;

localparam ADD_RK_OUT = 2'b01;

localparam INPUT      = 2'b10;

//=============================================================================

// KEY_SEL

//=============================================================================

localparam KEY_HOST = 1'b0;

localparam KEY_OUT  = 1'b1;

//=============================================================================

// KEY_EN

//=============================================================================

localparam KEY_DIS  = 4'b0000;

localparam EN_KEY_0 = 4'b0001;

localparam EN_KEY_1 = 4'b0010;

localparam EN_KEY_2 = 4'b0100;

localparam EN_KEY_3 = 4'b1000;

localparam KEY_ALL  = 4'b1111;

//=============================================================================

// COL_EN

//=============================================================================

localparam COL_DIS  = 4'b0000;

localparam EN_COL_0 = 4'b0001;

localparam EN_COL_1 = 4'b0010;

localparam EN_COL_2 = 4'b0100;

localparam EN_COL_3 = 4'b1000;

localparam COL_ALL  = 4'b1111;

//=============================================================================

// IV_CNT_SEL

//=============================================================================

localparam IV_CNT = 1'b1;

localparam IV_BUS = 1'b0;

//=============================================================================

// ENABLES

//=============================================================================

localparam ENABLE = 1'b1;

localparam DISABLE = 1'b0;

reg [31 : 0] col     [0:3];

reg [31 : 0] key     [0:3];

reg [31 : 0] key_host[0:3];

reg [31 : 0] bkp     [0:3];

reg [31 : 0] bkp_1   [0:3];

reg [31 : 0] iv      [0:3];

reg  [127 : 0] col_in;

reg  [ 31 : 0] data_in;

reg  [ 31 : 0] add_rd_key_in;

reg  [ 31 : 0] sbox_input;

reg  [ 31 : 0] key_mux_out;

reg  [ 31 : 0] iv_mux_out;

reg  [ 31 : 0] bkp_mux_out;

wire [127 : 0] key_in, key_out;

wire [127 : 0] sr_input;

wire [127 : 0] sr_enc, sr_dec;

wire [ 31 : 0] add_rk_out;

wire [ 31 : 0] sbox_out_enc;

wire [ 31 : 0] sbox_out_dec;

wire [ 31 : 0] g_in;

wire [ 31 : 0] mix_out_enc;

wire [ 31 : 0] mix_out_dec;

wire [ 31 : 0] add_rd;

wire [ 31 : 0] bus_swap;

wire [ 31 : 0] iv_bkp_mux;

wire [ 31 : 0] xor_input_bkp_iv;

wire [ 31 : 0] sr_input_0;

wire [ 31 : 0] sr_input_3;

wire [  3 : 0] key_en_sel;

wire [  3 : 0] bkp_en;

wire [  3 : 0] col_en;

wire [  1 : 0] key_mux_sel;

wire [  1 : 0] rk_sel_mux;

wire [  1 : 0] col_sel_w_bypass;

wire [  3 : 0] col_en_w_bypass;

wire rk_out_sel;

wire add_rk_sel;

wire key_sel_mux;

wire key1_mux_cnt;

wire enc_dec_sbox;

reg [31 : 0] sbox_pp2;

reg [ 3 : 0] col_en_cnt_unit_pp1;

reg [ 3 : 0] col_en_cnt_unit_pp2;

reg [ 3 : 0] key_en_pp1;

reg [ 3 : 0] round_pp1;

reg [ 1 : 0] col_sel_pp1;

reg [ 1 : 0] col_sel_pp2;

reg [ 1 : 0] key_out_sel_pp1;

reg [ 1 : 0] key_out_sel_pp2;

reg [ 1 : 0] rk_sel_pp1;

reg [ 1 : 0] rk_sel_pp2;

reg key_sel_pp1;

reg rk_out_sel_pp1, rk_out_sel_pp2;

reg last_round_pp1, last_round_pp2;

//reg end_aes_pp2,end_aes_pp1;//end_aes_pp2;

assign key_bus = key_mux_out;

assign iv_bus = iv_mux_out;

// Input Swap Unit

data_swap SWAP_IN

(

        .data_swap( bus_swap  ),

        .data_in  ( bus_in    ),

        .swap_type( data_type )

);

// Output Swap Unit

data_swap SWAP_OUT

(

        .data_swap( col_bus    ),

        .data_in  ( sbox_input ),

        .swap_type( data_type  )

);

// IV and BKP Muxs

always @(*)

        begin: IV_BKP_MUX

                integer i;

                iv_mux_out  = {32{1'b0}};

                bkp_mux_out = {32{1'b0}};

                for(i = 0; i < 4; i = i + 1)

                        begin

                                if(col_en[i] | iv_sel_rd[i])

                                        begin

                                                iv_mux_out  = iv[i];

                                                bkp_mux_out = bkp[i];

                                        end

                        end

        end

assign iv_bkp_mux = (first_block && !mode_ctr) ? iv_mux_out : bkp_mux_out;

assign xor_input_bkp_iv = ((enc_dec && !mode_ctr) ? bus_swap : add_rk_out) ^ iv_bkp_mux;

always @(*)

        begin

                data_in = {32{1'b0}};

                case(1'b1)

                        mode_cbc:

                                data_in = (enc_dec || last_round) ? xor_input_bkp_iv : bus_swap;

                        mode_ctr:

                                data_in = (last_round) ? xor_input_bkp_iv : iv_mux_out;

                        default:

                                data_in = bus_swap;

                endcase

        end

assign bkp_en = ( {4{ mode_cbc && last_round && enc_dec}} & col_en_cnt_unit_pp2) |

                ( {4{(mode_cbc && !enc_dec) || mode_ctr}} & col_en_host     );

// IV and BKP Registers

generate

        genvar l;

        for(l = 0; l < 4;l=l+1)

        begin

                always @(posedge clk, negedge rst_n)

                begin

                                if(!rst_n)

                                begin

                                                iv[l]    <= {32{1'b0}};

                                                bkp[l]   <= {32{1'b0}};

                                                bkp_1[l] <= {32{1'b0}};

                                end

                                else

                                begin

                                                if(l == 3)

                                                begin

                                                                if(iv_en[l] || iv_cnt_en)

                                                                begin

                                                                        /*

                                                                        if(mode_ctr)

                                                                                iv[l] <= (iv_cnt_sel) ? iv[l] + 1'b1 : bus_in;

                                                                        else

                                                                                iv[l] <= (iv_cnt_sel) ? iv[l] : bus_in;

                                                                        */

                                                                        iv[l] <= (iv_cnt_sel) ? iv[l] : bus_in;

                                                                end

                                                end

                                                else

                                                begin

                                                                if(iv_en[l])

                                                                        iv[l] <= bus_in;

                                                end

                                        if(bkp_en[l])

                                                //bkp[l] <= (mode_ctr) ? bus_swap : ((mode_cbc && enc_dec) ? col_in : bkp_1[l]);

                                        bkp[l] <= (mode_ctr) ? bus_swap : ((mode_cbc && enc_dec)? col_in[32*(l + 1) - 1 : 32*l] : bkp_1[l]);

                                        if(bkp_en[l])

                                                bkp_1[l] <= col_in[32*(l + 1) - 1 : 32*l];

                                end

                        end

                end

endgenerate

assign col_sel_w_bypass = (bypass_rk) ? col_sel : col_sel_pp2;

// Columns Input Multiplexors

always @(*)

        begin

                col_in = {128{1'b0}};

                case(col_sel_w_bypass)

                        SHIFT_ROWS:

                                col_in = (enc_dec) ? sr_enc : sr_dec;

                        ADD_RK_OUT:

                                col_in = {4{add_rk_out}};

                        INPUT:

                                col_in = {4{data_in}};

                endcase

        end

assign col_en_w_bypass = (bypass_rk) ? col_en_cnt_unit : col_en_cnt_unit_pp2;

assign col_en = col_en_host | col_en_w_bypass;

// Columns Definition

generate

        genvar i;

        for(i = 0; i < 4; i = i + 1)

                always @(posedge clk, negedge rst_n)

                        begin

                                if(!rst_n)

                                        col[3 - i] <= {32{1'b0}};

                                else

                                if(col_en[3 - i])

                                        col[3 - i] <= col_in[32*(i + 1) - 1 : 32*i];

                        end

endgenerate

// Shift Rows Operation

assign sr_input_3 = (enc_dec) ? add_rk_out : col[3];

assign sr_input_0 = (enc_dec) ? col[0] : add_rk_out;

assign sr_input = {sr_input_0, col[1], col[2], sr_input_3};

shift_rows SHIFT_ROW

(

        .data_out_enc  ( sr_enc   ),

        .data_out_dec  ( sr_dec   ),

  .data_in       ( sr_input )

);

//SBOX Input Multiplexor

always @(*)

        begin

                sbox_input = {32{1'b0}};

                case(sbox_sel | col_sel_host)

                        COL_0:

                                sbox_input = col[0];

                        COL_1:

                                sbox_input = col[1];

                        COL_2:

                                sbox_input = col[2];

                        COL_3:

                                sbox_input = col[3];

                        G_FUNCTION:

                                sbox_input = g_in;

                endcase

        end

// 32 bits SBOX

assign enc_dec_sbox = enc_dec | key_gen;

 sBox SBOX

  (

    .sbox_out_enc ( sbox_out_enc ),

                .sbox_out_dec ( sbox_out_dec ),

    .sbox_in      ( sbox_input   ),

    .enc_dec      ( enc_dec_sbox ),

                .clk          ( clk          )

  );

// Second stage of pipeline

always @(posedge clk)

        begin

                sbox_pp2 <= (enc_dec || mode_ctr) ? sbox_out_enc : sbox_out_dec ^ key_mux_out;

        end

assign key_en_sel  = (bypass_key_en) ? key_en : key_en_pp1;

assign key_sel_mux = (bypass_key_en) ? key_sel : key_sel_pp1;

// Key registers

generate

        genvar j;

        for(j = 0; j < 4; j = j + 1)

                always @(posedge clk, negedge rst_n)

                        begin

                                if(!rst_n)

                                        begin

                                                key_host[3 - j] <= {32{1'b0}};

                                                key[3 - j] <= {32{1'b0}};

                                        end

                                else

                                        begin

                                                if(key_host_en[3 - j] || key_derivation_en)

                                                        key_host[3 - j] <= (key_derivation_en) ? key[3 - j] : bus_in;

                                                if(key_en_sel[3 - j] || key_init || key_host_en[3 - j])

                                                        key[3 - j] <= (key_sel_mux) ? key_out[32*(j + 1) - 1 : 32*j] : ( (key_host_en[3 - j]) ? bus_in : key_host[3 - j] );

                                        end

                        end

endgenerate

assign key_in = {key[0], key[1], key[2], key[3]};

assign key1_mux_cnt = bypass_key_en & enc_dec;

key_expander KEY_EXPANDER

(

        .key_out   ( key_out       ),

        .g_in              ( g_in          ),

        .g_out     ( sbox_out_enc  ),

        .key_in    ( key_in        ),

        .round     ( round_pp1     ),

        .add_w_out ( key1_mux_cnt  ),

        .enc_dec   ( enc_dec | key_gen)

);

assign key_mux_sel = (bypass_key_en) ? key_out_sel : ( (enc_dec | mode_ctr) ? key_out_sel_pp2 : key_out_sel_pp1 );

// Key Expander Mux

always @(*)

        begin

                key_mux_out = {32{1'b0}};

                case(key_mux_sel | key_sel_rd)

                        KEY_0:

                                key_mux_out = key[0];

                        KEY_1:

                                key_mux_out = key[1];

                        KEY_2:

                                key_mux_out = key[2];

                        KEY_3:

                                key_mux_out = key[3];

                endcase

        end

  mix_columns MIX_COL

  (

    .mix_out_enc ( mix_out_enc  ),

                .mix_out_dec ( mix_out_dec  ),

    .mix_in      ( sbox_pp2     )

  );

assign rk_sel_mux = (bypass_rk) ? rk_sel : rk_sel_pp2;

always @(*)

        begin

                add_rd_key_in = {32{1'b0}};

                case(rk_sel_mux)

                        COL:

                                add_rd_key_in = sbox_input;

                        MIXCOL_IN:

                                add_rd_key_in = sbox_pp2;

                        MIXCOL_OUT:

                                add_rd_key_in = mix_out_enc;

                endcase

        end

// Add Round Key

assign add_rd = add_rd_key_in ^ key_mux_out;

assign rk_out_sel = (enc_dec | mode_ctr | bypass_rk);

assign add_rk_sel = (bypass_rk) ? rk_out_sel : rk_out_sel_pp2;

assign add_rk_out = (add_rk_sel) ? add_rd : (last_round_pp2 ? sbox_pp2 : mix_out_dec);

assign end_aes = end_comp;

// Pipeline Registers for Control Signals

always @(posedge clk, negedge rst_n)

        begin

                if(!rst_n)

                        begin

                                //end_aes_pp1 <= DISABLE;

                                //end_aes_pp2 <= DISABLE;

                                col_sel_pp1 <= INPUT;

                                col_sel_pp2 <= INPUT;

                                col_en_cnt_unit_pp1 <= COL_DIS;

                                col_en_cnt_unit_pp2 <= COL_DIS;

                                key_sel_pp1 <= KEY_HOST;

                                key_en_pp1  <= KEY_DIS;

                                round_pp1 <= 4'b0000;

                                key_out_sel_pp1 <= KEY_0;

                                key_out_sel_pp2 <= KEY_0;

                                rk_sel_pp1 <= COL;

                                rk_sel_pp2 <= COL;

                                rk_out_sel_pp1 <= 1'b1;

                                rk_out_sel_pp2 <= 1'b1;

                                last_round_pp1 <= 1'b1;

                                last_round_pp2 <= 1'b0;

                        end

                else

                        begin

                                col_sel_pp1 <= col_sel;

                                col_sel_pp2 <= col_sel_pp1;

                                if(!bypass_rk)

                                        begin

                                                col_en_cnt_unit_pp1 <= col_en_cnt_unit;

                                                col_en_cnt_unit_pp2 <= col_en_cnt_unit_pp1;

                                        end

                                key_sel_pp1 <= key_sel;

                                if(!bypass_key_en)

                                        key_en_pp1 <= key_en;

                                round_pp1 <= round;

                                key_out_sel_pp1 <= key_out_sel;

                                key_out_sel_pp2 <= key_out_sel_pp1;

                                rk_sel_pp1 <= rk_sel;

                                rk_sel_pp2 <= rk_sel_pp1;

                                rk_out_sel_pp1 <= rk_out_sel;

                                rk_out_sel_pp2 <= rk_out_sel_pp1;

                                last_round_pp1 <= last_round;

                                last_round_pp2 <= last_round_pp1;

                                //end_aes_pp1 <= end_comp;

                                //end_aes_pp2 <= end_aes_pp1;

                        end

        end

endmodule