//======================================================================
//
// mkmif.v
// -------
// Top level wrapper for the Master Key Memory (MKM) interface.
// The interface is implemented to use the Microchip 23K640 serial
// sram as external storage. The core acts as a SPI Master for the
// external memory including SPI clock generation.
//
// The current version of the core does not provide any functionality
// to protect against remanence.
//
//
// Author: Joachim Strombergson
// 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
// 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 mkmif(
input wire clk,
input wire reset_n,
output wire spi_sclk,
output wire spi_cs_n,
input wire spi_do,
output wire spi_di,
input wire cs,
input wire we,
input wire [7 : 0] address,
input wire [31 : 0] write_data,
output wire [31 : 0] read_data
);
//----------------------------------------------------------------
// 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_READ_BIT = 0;
localparam CTRL_WRITE_BIT = 1;
localparam CTRL_INIT_BIT = 2;
localparam ADDR_STATUS = 8'h09;
localparam STATUS_READY_BIT = 0;
localparam STATUS_VALID_BIT = 1;
localparam ADDR_SCLK_DIV = 8'h0a;
localparam ADDR_EMEM_ADDR = 8'h10;
localparam ADDR_EMEM_DATA = 8'h20;
localparam DEFAULT_SCLK_DIV = 16'h0020;
localparam CORE_NAME0 = 32'h6d6b6d69; // "mkmi"
localparam CORE_NAME1 = 32'h66202020; // "f "
localparam CORE_VERSION = 32'h302e3130; // "0.10"
//----------------------------------------------------------------
// Registers including update variables and write enable.
//----------------------------------------------------------------
reg read_op_reg;
reg read_op_new;
reg write_op_reg;
reg write_op_new;
reg init_op_reg;
reg init_op_new;
reg [15 : 0] addr_reg;
reg addr_we;
reg [15 : 0] sclk_div_reg;
reg sclk_div_we;
reg [31 : 0] write_data_reg;
reg write_data_we;
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
wire core_ready;
wire core_valid;
wire [31 : 0] core_read_data;
reg [31 : 0] tmp_read_data;
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
assign read_data = tmp_read_data;
//----------------------------------------------------------------
// core
//----------------------------------------------------------------
mkmif_core core(
.clk(clk),
.reset_n(reset_n),
.spi_sclk(spi_sclk),
.spi_cs_n(spi_cs_n),
.spi_do(spi_do),
.spi_di(spi_di),
.read_op(read_op_reg),
.write_op(write_op_reg),
.init_op(init_op_reg),
.ready(core_ready),
.valid(core_valid),
.sclk_div(sclk_div_reg),
.addr(addr_reg),
.write_data(write_data_reg),
.read_data(core_read_data)
);
//----------------------------------------------------------------
// 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
if (!reset_n)
begin
read_op_reg <= 1'h0;
write_op_reg <= 1'h0;
addr_reg <= 16'h0;
sclk_div_reg <= DEFAULT_SCLK_DIV;
write_data_reg <= 32'h0;
end
else
begin
read_op_reg <= read_op_new;
write_op_reg <= write_op_new;
init_op_reg <= init_op_new;
if (sclk_div_we)
sclk_div_reg <= write_data[15 : 0];
if (addr_we)
addr_reg <= write_data[15 : 0];
if (write_data_we)
write_data_reg <= write_data;
end
end // reg_update
//----------------------------------------------------------------
// api
//----------------------------------------------------------------
always @*
begin : api
read_op_new = 0;
write_op_new = 0;
init_op_new = 0;
addr_we = 0;
sclk_div_we = 0;
write_data_we = 0;
tmp_read_data = 32'h00000000;
if (cs)
begin
if (we)
begin
case (address)
ADDR_CTRL:
begin
read_op_new = write_data[CTRL_READ_BIT];
write_op_new = write_data[CTRL_WRITE_BIT];
init_op_new = write_data[CTRL_INIT_BIT];
end
ADDR_SCLK_DIV:
sclk_div_we = 1;
ADDR_EMEM_ADDR:
addr_we = 1;
ADDR_EMEM_DATA:
write_data_we = 1;
default:
begin
end
endcase // case (address)
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_STATUS:
tmp_read_data = {30'h0, {core_valid, core_ready}};
ADDR_SCLK_DIV:
tmp_read_data = {16'h0, sclk_div_reg};
ADDR_EMEM_ADDR:
tmp_read_data = {16'h0, addr_reg};
ADDR_EMEM_DATA:
begin
tmp_read_data = core_read_data;
end
default:
begin
end
endcase // case (address)
end
end
end // api
endmodule // mkmif
//======================================================================
// EOF mkmif.v
//======================================================================
