//======================================================================
//
// Copyright (c) 2016, 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
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//
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// 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
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//======================================================================
`timescale 1ns / 1ps
module ecdsa256
(
input wire clk,
input wire rst_n,
input wire next,
output wire valid,
input wire bus_cs,
input wire bus_we,
input wire [ 4:0] bus_addr,
input wire [31:0] bus_data_wr,
output wire [31:0] bus_data_rd
);
//
// Memory Banks
//
localparam [1:0] BUS_ADDR_BANK_K = 2'b00;
localparam [1:0] BUS_ADDR_BANK_X = 2'b01;
localparam [1:0] BUS_ADDR_BANK_Y = 2'b10;
wire [1:0] bus_addr_upper = bus_addr[4:3];
wire [2:0] bus_addr_lower = bus_addr[2:0];
//
// Memories
//
wire [31:0] user_rw_k_bram_out;
wire [31:0] user_ro_x_bram_out;
wire [31:0] user_ro_y_bram_out;
wire [ 2:0] core_ro_k_bram_addr;
wire [ 2:0] core_rw_x_bram_addr;
wire [ 2:0] core_rw_y_bram_addr;
wire core_rw_x_bram_wren;
wire core_rw_y_bram_wren;
wire [31:0] core_ro_k_bram_dout;
wire [31:0] core_rw_x_bram_din;
wire [31:0] core_rw_y_bram_din;
bram_1rw_1ro_readfirst #
( .MEM_WIDTH(32), .MEM_ADDR_BITS(3)
)
bram_k
( .clk(clk),
.a_addr(bus_addr_lower), .a_out(user_rw_k_bram_out), .a_wr(bus_cs && bus_we && (bus_addr_upper == BUS_ADDR_BANK_K)), .a_in(bus_data_wr),
.b_addr(core_ro_k_bram_addr), .b_out(core_ro_k_bram_dout)
);
bram_1rw_1ro_readfirst #
( .MEM_WIDTH(32), .MEM_ADDR_BITS(3)
)
bram_x
( .clk(clk),
.a_addr(core_rw_x_bram_addr), .a_out(), .a_wr(core_rw_x_bram_wren), .a_in(core_rw_x_bram_din),
.b_addr(bus_addr_lower), .b_out(user_ro_x_bram_out)
);
bram_1rw_1ro_readfirst #
( .MEM_WIDTH(32), .MEM_ADDR_BITS(3)
)
bram_y
( .clk(clk),
.a_addr(core_rw_y_bram_addr), .a_out(), .a_wr(core_rw_y_bram_wren), .a_in(core_rw_y_bram_din),
.b_addr(bus_addr_lower), .b_out(user_ro_y_bram_out)
);
//
// Montgomery Coefficient Calculator
//
reg next_dly;
always @(posedge clk) next_dly <= next;
wire next_trig = next && !next_dly;
curve_mul_256 base_point_multiplier_p256
(
.clk (clk),
.rst_n (rst_n),
.ena (next_trig),
.rdy (valid),
.k_addr (core_ro_k_bram_addr),
.rx_addr (core_rw_x_bram_addr),
.ry_addr (core_rw_y_bram_addr),
.rx_wren (core_rw_x_bram_wren),
.ry_wren (core_rw_y_bram_wren),
.k_din (core_ro_k_bram_dout),
.rx_dout (core_rw_x_bram_din),
.ry_dout (core_rw_y_bram_din)
);
//
// Output Selector
//
reg [1:0] bus_addr_upper_prev;
always @(posedge clk) bus_addr_upper_prev = bus_addr_upper;
reg [31: 0] bus_data_rd_mux;
assign bus_data_rd = bus_data_rd_mux;
always @(*)
//
case (bus_addr_upper_prev)
//
BUS_ADDR_BANK_K: bus_data_rd_mux = user_rw_k_bram_out;
BUS_ADDR_BANK_X: bus_data_rd_mux = user_ro_x_bram_out;
BUS_ADDR_BANK_Y: bus_data_rd_mux = user_ro_y_bram_out;
//
default: bus_data_rd_mux = {32{1'b0}};
//
endcase
endmodule
