//======================================================================
//
// novena_top.v
// ------------
// Top module for the Cryptech Novena FPGA framework with the I2C bus.
//
//
// Author: Pavel Shatov
// Copyright (c) 2015, 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 novena_top
(
// Differential input for 50 MHz general clock.
input wire gclk_p_pin,
input wire gclk_n_pin,
// Reset controlled by the CPU.
// this must be configured as input w/pullup
input wire reset_mcu_b_pin,
// Cryptech avalanche noise board input and LED outputs
input wire ct_noise,
output wire [7 : 0] ct_led,
// I2C interface
input wire i2c_scl,
inout wire i2c_sda,
// Novena utility ports
output wire apoptosis_pin, // Hold low to not restart after config.
output wire led_pin // LED on edge close to the FPGA.
);
//----------------------------------------------------------------
// Clock Manager
//
// Clock manager is used to generate SYS_CLK from GCLK
// and implement the reset logic.
// ----------------------------------------------------------------
wire sys_clk;
wire sys_rst;
novena_clkmgr clkmgr
(
.gclk_p(gclk_p_pin),
.gclk_n(gclk_n_pin),
.reset_mcu_b(reset_mcu_b_pin),
.sys_clk(sys_clk),
.sys_rst(sys_rst)
);
//----------------------------------------------------------------
// I2C Interface
//
// I2C subsystem handles all data transfer to/from CPU via I2C bus.
//----------------------------------------------------------------
parameter I2C_DEVICE_ADDR = 7'h0f;
wire [16: 0] sys_eim_addr;
wire sys_eim_wr;
wire sys_eim_rd;
wire sda_pd;
wire sda_int;
wire clk = sys_clk;
wire reset_n = ~sys_rst;
// Coretest connections.
wire coretest_reset_n;
wire coretest_cs;
wire coretest_we;
wire [15 : 0] coretest_address;
wire [31 : 0] coretest_write_data;
wire [31 : 0] coretest_read_data;
// I2C connections
wire [6:0] i2c_device_addr;
wire i2c_rxd_syn;
wire [7 : 0] i2c_rxd_data;
wire i2c_rxd_ack;
wire i2c_txd_syn;
wire [7 : 0] i2c_txd_data;
wire i2c_txd_ack;
IOBUF #(.DRIVE(8), .SLEW("SLOW"))
IOBUF_sda (
.IO(i2c_sda),
.I(1'b0),
.T(!sda_pd),
.O(sda_int)
);
i2c_core i2c_core
(
.clk(clk),
.reset(sys_rst),
// External data interface
.SCL(i2c_scl),
.SDA(sda_int),
.SDA_pd(sda_pd),
.i2c_device_addr(i2c_device_addr),
// Internal receive interface.
.rxd_syn(i2c_rxd_syn),
.rxd_data(i2c_rxd_data),
.rxd_ack(i2c_rxd_ack),
// Internal transmit interface.
.txd_syn(i2c_txd_syn),
.txd_data(i2c_txd_data),
.txd_ack(i2c_txd_ack)
);
coretest coretest
(
.clk(clk),
.reset_n(reset_n),
.rx_syn(i2c_rxd_syn),
.rx_data(i2c_rxd_data),
.rx_ack(i2c_rxd_ack),
.tx_syn(i2c_txd_syn),
.tx_data(i2c_txd_data),
.tx_ack(i2c_txd_ack),
// Interface to the core being tested.
.core_reset_n(coretest_reset_n),
.core_cs(coretest_cs),
.core_we(coretest_we),
.core_address(coretest_address),
.core_write_data(coretest_write_data),
.core_read_data(coretest_read_data)
);
wire select = (i2c_device_addr == I2C_DEVICE_ADDR);
assign sys_eim_addr = { coretest_address[15:13], 1'b0, coretest_address[12:0] };
assign sys_eim_wr = select & coretest_cs & coretest_we;
assign sys_eim_rd = select & coretest_cs & ~coretest_we;
//----------------------------------------------------------------
// Core Selector
//
// This multiplexer is used to map different types of cores, such as
// hashes, RNGs and ciphers to different regions (segments) of memory.
//----------------------------------------------------------------
core_selector cores
(
.sys_clk(clk),
.sys_rst(sys_rst),
.noise(ct_noise),
.sys_eim_addr(sys_eim_addr),
.sys_eim_wr(sys_eim_wr),
.sys_eim_rd(sys_eim_rd),
.sys_write_data(coretest_write_data),
.sys_read_data(coretest_read_data)
);
//----------------------------------------------------------------
// Cryptech Logic
//
// Logic specific to the Cryptech use of the Novena.
// Currently we just hard wire the LED outputs.
//----------------------------------------------------------------
assign ct_led = {8{ct_noise}};
//----------------------------------------------------------------
// Novena Patch
//
// Patch logic to keep the Novena board happy.
// The apoptosis_pin pin must be kept low or the whole board
// (more exactly the CPU) will be reset after the FPGA has
// been configured.
//----------------------------------------------------------------
assign apoptosis_pin = 1'b0;
assign led_pin = 1'b1;
endmodule
//======================================================================
// EOF novena_top.v
//======================================================================
