130 lines
3.6 KiB
Verilog
130 lines
3.6 KiB
Verilog
//======================================================================
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//
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// figaro.v
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// --------
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// Top level wrapper for the figaro core.
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//
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//
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// Author: Joachim Strombergson
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// Copyright (C) 2022 - Tillitis AB
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// SPDX-License-Identifier: GPL-2.0-only
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//
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//======================================================================
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`default_nettype none
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module figaro(
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input wire clk,
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input wire reset_n,
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input wire cs,
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input wire we,
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input wire [7 : 0] address,
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input wire [31 : 0] write_data,
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output wire [31 : 0] read_data,
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output wire ready
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);
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//----------------------------------------------------------------
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// Internal constant and parameter definitions.
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//----------------------------------------------------------------
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localparam ADDR_NAME0 = 8'h00;
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localparam ADDR_NAME1 = 8'h01;
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localparam ADDR_VERSION = 8'h02;
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localparam ADDR_STATUS = 8'h09;
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localparam STATUS_READY_BIT = 0;
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localparam ADDR_SAMPLE_RATE = 8'h10;
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localparam ADDR_ENTROPY = 8'h20;
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localparam CORE_NAME0 = 32'h66696761; // "figa"
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localparam CORE_NAME1 = 32'h726f2020; // "ro "
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localparam CORE_VERSION = 32'h00000001;
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//----------------------------------------------------------------
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// Wires.
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//----------------------------------------------------------------
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reg core_read_entropy;
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reg core_set_sample_rate;
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wire [31 : 0] core_entropy;
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wire core_ready;
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reg [31 : 0] tmp_read_data;
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reg tmp_ready;
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//----------------------------------------------------------------
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// Concurrent connectivity for ports etc.
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//----------------------------------------------------------------
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assign read_data = tmp_read_data;
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assign ready = tmp_ready;
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//----------------------------------------------------------------
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// core instantiation.
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//----------------------------------------------------------------
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figaro_core core(
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.clk(clk),
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.reset_n(reset_n),
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.read_entropy(core_read_entropy),
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.set_sample_rate(core_set_sample_rate),
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.sample_rate(write_data[23 : 0]),
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.entropy(core_entropy),
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.ready(core_ready)
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);
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//----------------------------------------------------------------
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// api
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//
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// The interface command decoding logic.
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//----------------------------------------------------------------
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always @*
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begin : api
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core_read_entropy = 1'h0;
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core_set_sample_rate = 1'h0;
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tmp_read_data = 32'h0;
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tmp_ready = 1'h0;
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if (cs) begin
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tmp_ready = 1'h1;
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if (we) begin
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if (address == ADDR_SAMPLE_RATE) begin
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core_set_sample_rate = 1'h1;
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end
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end
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else begin
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if (address == ADDR_NAME0) begin
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tmp_read_data = CORE_NAME0;
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end
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if (address == ADDR_NAME1) begin
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tmp_read_data = CORE_NAME1;
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end
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if (address == ADDR_VERSION) begin
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tmp_read_data = CORE_VERSION;
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end
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if (address == ADDR_STATUS) begin
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tmp_read_data = {31'h0, core_ready};
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end
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if (address == ADDR_ENTROPY) begin
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tmp_read_data = core_entropy;
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core_read_entropy = 1'h1;
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end
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end
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end
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end // api
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endmodule // figaro
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//======================================================================
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// EOF figaro.v
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//======================================================================
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