//======================================================================
//
// novena_top.v
// ------------
// Top module for the Cryptech Novena FPGA framework. This design
// allow us to run the EIM interface at one clock and cores including
// core selector with the always present global clock.
//
//
// 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.
//
//======================================================================
`timescale 1ns / 1ps
module novena_fmc_top
(
input wire gclk_p_pin,
input wire gclk_n_pin,
input wire reset_mcu_b_pin,
// Cryptech avalanche noise board input
input wire ct_noise,
input wire fmc_clk, // clock
input wire [21: 0] fmc_a, // address
inout wire [31: 0] fmc_d, // data
input wire fmc_ne1, // chip select
input wire fmc_noe, // output enable
input wire fmc_nwe, // write enable
input wire fmc_nl, // latch enable
output wire fmc_nwait,// wait
output wire apoptosis_pin,
output wire led_pin
);
//----------------------------------------------------------------
// Clock Manager
//
// Clock manager is used to generate SYS_CLK from GCLK
// and implement the reset logic.
// ----------------------------------------------------------------
wire sys_clk;
wire sys_rst_n;
novena_clkmgr #
(
.CLK_OUT_MUL (2), // 2..32
.CLK_OUT_DIV (2) // 1..32
)
clkmgr
(
.gclk_p (gclk_p_pin),
.gclk_n (gclk_n_pin),
.reset_mcu_b (reset_mcu_b_pin),
.sys_clk (sys_clk),
.sys_rst_n (sys_rst_n)
);
//
// BUFG
//
wire fmc_clk_bug;
BUFG BUFG_fmc_clk
(
.I (fmc_clk),
.O (fmc_clk_bufg)
);
//----------------------------------------------------------------
// FMC Arbiter
//
// FMC arbiter handles FMC access and transfers it into
// `sys_clk' clock domain.
//----------------------------------------------------------------
wire [21: 0] sys_fmc_addr; // address
wire sys_fmc_wren; // write enable
wire sys_fmc_rden; // read enable
wire [31: 0] sys_fmc_dout; // data output (from STM32 to FPGA)
`ifdef test
reg [31: 0] sys_fmc_din; // data input (from FPGA to STM32)
`else
wire [31: 0] sys_fmc_din; // data input (from FPGA to STM32)
`endif
fmc_arbiter #
(
.NUM_ADDR_BITS(22) // change to 26 when
)
fmc
(
.fmc_clk(fmc_clk_bufg),
.fmc_a(fmc_a),
.fmc_d(fmc_d),
.fmc_ne1(fmc_ne1),
.fmc_nl(fmc_nl),
.fmc_nwe(fmc_nwe),
.fmc_noe(fmc_noe),
.fmc_nwait(fmc_nwait),
.sys_clk(sys_clk),
.sys_addr(sys_fmc_addr),
.sys_wr_en(sys_fmc_wren),
.sys_rd_en(sys_fmc_rden),
.sys_data_out(sys_fmc_dout),
.sys_data_in(sys_fmc_din)
);
//----------------------------------------------------------------
// LED Driver
//
// A simple utility LED driver that turns on the Novena
// board LED when the FMC interface is active.
//----------------------------------------------------------------
fmc_indicator led
(
.sys_clk(sys_clk),
.sys_rst_n(sys_rst_n),
.fmc_active(sys_fmc_wren | sys_fmc_rden),
.led_out(led_pin)
);
`ifdef test
//----------------------------------------------------------------
// Dummy Register
//
// General-purpose register to test FMC interface using STM32
// demo program instead of core selector logic.
//
// This register is a bit tricky, but it allows testing of both
// data and address buses. Reading from FPGA will always return
// value, which is currently stored in the test register,
// regardless of read transaction address. Writing to FPGA has
// two variants: a) writing to address 0 will store output data
// data value in the test register, b) writing to any non-zero
// address will store _address_ of write transaction in the test
// register.
//
// To test data bus, write some different patterns to address 0,
// then readback from any address and compare.
//
// To test address bus, write anything to some different non-zero
// addresses, then readback from any address and compare returned
// value with previously written address.
//
//----------------------------------------------------------------
reg [31: 0] test_reg;
always @(posedge sys_clk)
//
if (sys_fmc_wren) begin
//
// when writing to address 0, store input data value
//
// when writing to non-zero address, store _address_
// (padded with zeroes) instead of data
//
test_reg <= (sys_fmc_addr == {22{1'b0}}) ? sys_fmc_dout : {{10{1'b0}}, sys_fmc_addr};
//
end else if (sys_fmc_rden) begin
//
// always return current value, ignore address
//
sys_fmc_din <= test_reg;
// when reading from address 0, return the current value
// when reading from other addresses, return the address
//sys_fmc_din <= (sys_fmc_addr == {22{1'b0}}) ? test_reg : {{10{1'b0}}, sys_fmc_addr};
//
end
`else // !`ifdef test
//----------------------------------------------------------------
// Core Selector
//
// This multiplexer is used to map different types of cores, such as
// hashes, RNGs and ciphers to different regions (segments) of memory.
//----------------------------------------------------------------
// A note on byte-swapping:
// STM32 is little-endian, while the register interface here is
// big-endian. The software reads and writes 32-bit integer values,
// which means transmitting the least significant byte first. Up to
// now, we've been doing byte-swapping in software, which is
// inefficient, especially for bulk data transfer. So now we're doing
// the byte-swapping in hardware.
wire [31:0] tmp_write_data;
assign tmp_write_data = {sys_fmc_dout[7:0], sys_fmc_dout[15:8], sys_fmc_dout[23:16], sys_fmc_dout[31:24]};
wire [31 : 0] tmp_read_data;
assign sys_fmc_din = {tmp_read_data[7:0], tmp_read_data[15:8], tmp_read_data[23:16], tmp_read_data[31:24]};
core_selector cores
(
.sys_clk(sys_clk),
.sys_rst_n(sys_rst_n),
.sys_eim_addr(sys_fmc_addr[16:0]), // XXX parameterize
.sys_eim_wr(sys_fmc_wren),
.sys_eim_rd(sys_fmc_rden),
.sys_write_data(tmp_write_data),
.sys_read_data(tmp_read_data),
.noise(ct_noise)
);
`endif
//----------------------------------------------------------------
// 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;
endmodule
