/*
 * ut_pkt.v
 *
 * USB Packet Receiver
 *
 * vim: ts=4 sw=4
 *
 * Copyright (C) 2022  Sylvain Munaut <tnt@246tNt.com>
 * SPDX-License-Identifier: CERN-OHL-P-2.0
 */

`default_nettype none

module ut_pkt (
	// Bus interface
	output wire [31:0] bus_rdata,
	input  wire [31:0] bus_wdata,
	input  wire        bus_we_csr,

	// USB tap
	input  wire        tap_dp,
	input  wire        tap_dn,

	// Data stream
	output wire  [7:0] stream_data,
	output wire        stream_stb,

	// Clock / Reset
	input  wire clk_1x,
	input  wire clk_2x,
	input  wire rst
);

	// Signals
	// -------

	// Control
	reg         ctrl_active;
	reg         ctrl_busy;

	// PHY
	wire        phy_rx_dp;
	wire        phy_rx_dn;
	wire        phy_rx_chg;

	// RX Low-Level
	wire  [1:0] ll_sym;
	wire        ll_bit;
	wire        ll_valid;
	wire        ll_eop;
	wire        ll_sync;
	wire        ll_bs_skip;
	wire        ll_bs_err;

	// Packet (clk_2x domain)
	wire        p2x_start;
	wire        p2x_done_ok;
	wire        p2x_done_err;

	wire  [3:0] p2x_pid;
	wire        p2x_is_sof;
	wire        p2x_is_token;
	wire        p2x_is_data;
	wire        p2x_is_handshake;

	wire [10:0] p2x_frameno;
	wire  [6:0] p2x_addr;
	wire  [3:0] p2x_endp;

	wire  [7:0] p2x_data;
	wire        p2x_data_stb;

	// Packet (clk_1x domain)
	wire        p1x_start;
	wire        p1x_done_ok;
	wire        p1x_done_err;

	wire  [3:0] p1x_pid;
	wire        p1x_is_sof;
	wire        p1x_is_token;
	wire        p1x_is_data;
	wire        p1x_is_handshake;

	wire [10:0] p1x_frameno;
	wire  [6:0] p1x_addr;
	wire  [3:0] p1x_endp;

	wire  [7:0] p1x_data;
	wire        p1x_data_stb;


	// Bus Interface
	// -------------

	assign bus_rdata = { 30'h00000000, ctrl_busy, ctrl_active };

	always @(posedge clk_1x or posedge rst)
		if (rst)
			ctrl_active <= 1'b0;
		else if (bus_we_csr)
			ctrl_active <= bus_wdata[0];

	always @(posedge clk_1x or posedge rst)
		if (rst)
			ctrl_busy <= 1'b0;
		else
			ctrl_busy <= (ctrl_busy & ~p1x_done_ok & ~p1x_done_err) | p1x_start;


	// PHY
	// ---

	usb_phy #(
		.TARGET("ICE40")
	) phy_I (
		.pad_dp (tap_dp),
		.pad_dn (tap_dn),
		.rx_dp  (phy_rx_dp),
		.rx_dn  (phy_rx_dn),
		.rx_chg (phy_rx_chg),
		.tx_dp  (1'b0),
		.tx_dn  (1'b0),
		.tx_en  (1'b0),
		.clk    (clk_2x),
		.rst    (rst)
	);


	// Low-Level RX
	// ------------

	usb_rx_ll rx_ll_I (
		.phy_rx_dp  (phy_rx_dp),
		.phy_rx_dn  (phy_rx_dn),
		.phy_rx_chg (phy_rx_chg),
		.ll_sym     (ll_sym),
		.ll_bit     (ll_bit),
		.ll_valid   (ll_valid),
		.ll_eop     (ll_eop),
		.ll_sync    (ll_sync),
		.ll_bs_skip (ll_bs_skip),
		.ll_bs_err  (ll_bs_err),
		.clk        (clk_2x),
		.rst        (rst)
	);


	// Packet RX
	// ---------

	usb_rx_pkt rx_pkt_I (
		.ll_sym           (ll_sym),
		.ll_bit           (ll_bit),
		.ll_valid         (ll_valid),
		.ll_eop           (ll_eop),
		.ll_sync          (ll_sync),
		.ll_bs_skip       (ll_bs_skip),
		.ll_bs_err        (ll_bs_err),
		.pkt_start        (p2x_start),
		.pkt_done_ok      (p2x_done_ok),
		.pkt_done_err     (p2x_done_err),
		.pkt_pid          (p2x_pid),
		.pkt_is_sof       (p2x_is_sof),
		.pkt_is_token     (p2x_is_token),
		.pkt_is_data      (p2x_is_data),
		.pkt_is_handshake (p2x_is_handshake),
		.pkt_frameno      (p2x_frameno),
		.pkt_addr         (p2x_addr),
		.pkt_endp         (p2x_endp),
		.pkt_data         (p2x_data),
		.pkt_data_stb     (p2x_data_stb),
		.inhibit          (~ctrl_active),
		.clk              (clk_2x),
		.rst              (rst)
	);


	// Cross-Clock
	// -----------

	ut_pkt_xclk xclk_I (
		.pi_start        (p2x_start),
		.pi_done_ok      (p2x_done_ok),
		.pi_done_err     (p2x_done_err),
		.pi_pid          (p2x_pid),
		.pi_is_sof       (p2x_is_sof),
		.pi_is_token     (p2x_is_token),
		.pi_is_data      (p2x_is_data),
		.pi_is_handshake (p2x_is_handshake),
		.pi_frameno      (p2x_frameno),
		.pi_addr         (p2x_addr),
		.pi_endp         (p2x_endp),
		.pi_data         (p2x_data),
		.pi_data_stb     (p2x_data_stb),
		.pi_clk          (clk_2x),
		.po_start        (p1x_start),
		.po_done_ok      (p1x_done_ok),
		.po_done_err     (p1x_done_err),
		.po_pid          (p1x_pid),
		.po_is_sof       (p1x_is_sof),
		.po_is_token     (p1x_is_token),
		.po_is_data      (p1x_is_data),
		.po_is_handshake (p1x_is_handshake),
		.po_frameno      (p1x_frameno),
		.po_addr         (p1x_addr),
		.po_endp         (p1x_endp),
		.po_data         (p1x_data),
		.po_data_stb     (p1x_data_stb),
		.po_clk          (clk_1x),
		.rst             (rst)
	);


	// Stream Generator
	// ----------------

	ut_pkt_stream stream_I (
		.phy_rx_dp        (phy_rx_dp),
		.phy_rx_dn        (phy_rx_dn),
		.pkt_start        (p1x_start),
		.pkt_done_ok      (p1x_done_ok),
		.pkt_done_err     (p1x_done_err),
		.pkt_pid          (p1x_pid),
		.pkt_is_sof       (p1x_is_sof),
		.pkt_is_token     (p1x_is_token),
		.pkt_is_data      (p1x_is_data),
		.pkt_is_handshake (p1x_is_handshake),
		.pkt_frameno      (p1x_frameno),
		.pkt_addr         (p1x_addr),
		.pkt_endp         (p1x_endp),
		.pkt_data         (p1x_data),
		.pkt_data_stb     (p1x_data_stb),
		.stream_data      (stream_data),
		.stream_stb       (stream_stb),
		.ctrl_active      (ctrl_active),
		.clk              (clk_1x),
		.rst              (rst)
	);

endmodule // ut_pkt