Subversion Repositories ulpi_wrapper

//-----------------------------------------------------------------

//                        ULPI (Link) Wrapper

//                              V0.1

//                        Ultra-Embedded.com

//                          Copyright 2015

//

//                 Email: admin@ultra-embedded.com

//

//                         License: GPL

// If you would like a version with a more permissive license for

// use in closed source commercial applications please contact me

// for details.

//-----------------------------------------------------------------

//

// This file is open source HDL; you can redistribute it and/or 

// modify it under the terms of the GNU General Public License as 

// published by the Free Software Foundation; either version 2 of 

// the License, or (at your option) any later version.

//

// This file is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public 

// License along with this file; if not, write to the Free Software

// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307

// USA

//-----------------------------------------------------------------

//-----------------------------------------------------------------

// Module: UTMI+ to ULPI Wrapper

//

// Description:

//   - Converts from UTMI interface to reduced pin count ULPI.

//   - No support for low power mode.

//   - I/O synchronous to 60MHz ULPI clock input (from PHY)

//   - Tested against SMSC/Microchip USB3300 in device mode.

//-----------------------------------------------------------------

module ulpi_wrapper

(

    // ULPI Interface (PHY)

    input             ulpi_clk60_i,

    input             ulpi_rst_i,

    input  [7:0]      ulpi_data_i,

    output [7:0]      ulpi_data_o,

    input             ulpi_dir_i,

    input             ulpi_nxt_i,

    output            ulpi_stp_o,

    // UTMI Interface (SIE)

    input             utmi_txvalid_i,

    output            utmi_txready_o,

    output            utmi_rxvalid_o,

    output            utmi_rxactive_o,

    output            utmi_rxerror_o,

    output [7:0]      utmi_data_o,

    input  [7:0]      utmi_data_i,

    input  [1:0]      utmi_xcvrselect_i,

    input             utmi_termselect_i,

    input  [1:0]      utmi_opmode_i,

    input             utmi_dppulldown_i,

    input             utmi_dmpulldown_i,

    output [1:0]      utmi_linestate_o

);

//-----------------------------------------------------------------

// States

//-----------------------------------------------------------------

localparam STATE_W          = 2;

localparam STATE_IDLE       = 2'd0;

localparam STATE_CMD        = 2'd1;

localparam STATE_DATA       = 2'd2;

localparam STATE_WAIT       = 2'd3;

reg [STATE_W-1:0]   state_q;

//-----------------------------------------------------------------

// UTMI Mode Select

//-----------------------------------------------------------------

reg         mode_update_q;

reg [1:0]   xcvrselect_q;

reg         termselect_q;

reg [1:0]   opmode_q;

reg         phy_reset_q;

always @ (posedge ulpi_clk60_i or posedge ulpi_rst_i)

if (ulpi_rst_i)

begin

    mode_update_q   <= 1'b0;

    xcvrselect_q    <= 2'b0;

    termselect_q    <= 1'b0;

    opmode_q        <= 2'b11;

    phy_reset_q     <= 1'b1;

end

else

begin

    xcvrselect_q    <= utmi_xcvrselect_i;

    termselect_q    <= utmi_termselect_i;

    opmode_q        <= utmi_opmode_i;

    if (mode_update_q && (state_q == STATE_IDLE) && !ulpi_dir_i)

    begin

        mode_update_q <= 1'b0;

        phy_reset_q   <= 1'b0;

    end

    else if (opmode_q     != utmi_opmode_i     ||

             termselect_q != utmi_termselect_i ||

             xcvrselect_q != utmi_xcvrselect_i)

        mode_update_q <= 1'b1;

end

//-----------------------------------------------------------------

// UTMI OTG Control

//-----------------------------------------------------------------

reg otg_update_q;

reg dppulldown_q;

reg dmpulldown_q;

always @ (posedge ulpi_clk60_i or posedge ulpi_rst_i)

if (ulpi_rst_i)

begin

    otg_update_q    <= 1'b0;

    dppulldown_q    <= 1'b1;

    dmpulldown_q    <= 1'b1;

end

else

begin

    dppulldown_q    <= utmi_dppulldown_i;

    dmpulldown_q    <= utmi_dmpulldown_i;

    if (otg_update_q && !mode_update_q && (state_q == STATE_IDLE) && !ulpi_dir_i)

        otg_update_q <= 1'b0;

    else if (dppulldown_q != utmi_dppulldown_i ||

             dmpulldown_q != utmi_dmpulldown_i)

        otg_update_q <= 1'b1;

end

//-----------------------------------------------------------------

// Bus turnaround detect

//-----------------------------------------------------------------

reg ulpi_dir_q;

always @ (posedge ulpi_clk60_i or posedge ulpi_rst_i)

if (ulpi_rst_i)

    ulpi_dir_q <= 1'b0;

else

    ulpi_dir_q <= ulpi_dir_i;

wire turnaround_w = ulpi_dir_q ^ ulpi_dir_i;

//-----------------------------------------------------------------

// Rx - Tx delay

//-----------------------------------------------------------------

localparam TX_DELAY_W       = 3;

localparam TX_START_DELAY   = 3'd7;

reg [TX_DELAY_W-1:0] tx_delay_q;

always @ (posedge ulpi_clk60_i or posedge ulpi_rst_i)

if (ulpi_rst_i)

    tx_delay_q <= {TX_DELAY_W{1'b0}};

else if (utmi_rxactive_o)

    tx_delay_q <= TX_START_DELAY;

else if (tx_delay_q != {TX_DELAY_W{1'b0}})

    tx_delay_q <= tx_delay_q - 1;

wire tx_delay_complete_w = (tx_delay_q == {TX_DELAY_W{1'b0}});

//-----------------------------------------------------------------

// Tx Buffer - decouple UTMI Tx from PHY I/O

//-----------------------------------------------------------------

reg [7:0] tx_buffer_q[0:1];

reg       tx_valid_q[0:1];

reg       tx_wr_idx_q;

reg       tx_rd_idx_q;

wire      utmi_tx_ready_w;

wire      utmi_tx_accept_w;

always @ (posedge ulpi_clk60_i or posedge ulpi_rst_i)

if (ulpi_rst_i)

begin

    tx_buffer_q[0] <= 8'b0;

    tx_buffer_q[1] <= 8'b0;

    tx_valid_q[0]  <= 1'b0;

    tx_valid_q[1]  <= 1'b0;

    tx_wr_idx_q    <= 1'b0;

    tx_rd_idx_q    <= 1'b0;

end

else

begin

    // Push

    if (utmi_txvalid_i && utmi_txready_o)

    begin

        tx_buffer_q[tx_wr_idx_q] <= utmi_data_i;

        tx_valid_q[tx_wr_idx_q]  <= 1'b1;

        tx_wr_idx_q <= tx_wr_idx_q + 1'b1;

    end

    // Pop

    if (utmi_tx_ready_w && utmi_tx_accept_w)

    begin

        tx_valid_q[tx_rd_idx_q]  <= 1'b0;

        tx_rd_idx_q <= tx_rd_idx_q + 1'b1;

    end

end

// Tx buffer space (only accept after Rx->Tx turnaround delay)

assign utmi_txready_o  = ~tx_valid_q[tx_wr_idx_q] & tx_delay_complete_w;

assign utmi_tx_ready_w = tx_valid_q[tx_rd_idx_q];

wire [7:0] utmi_tx_data_w = tx_buffer_q[tx_rd_idx_q];

//-----------------------------------------------------------------

// Implementation

//-----------------------------------------------------------------

// Xilinx placement pragmas:

//synthesis attribute IOB of ulpi_data_q is "TRUE"

//synthesis attribute IOB of ulpi_stp_q is "TRUE"

reg [7:0]           ulpi_data_q;

reg                 ulpi_stp_q;

reg [7:0]           data_q;

reg                 utmi_rxvalid_q;

reg                 utmi_rxerror_q;

reg                 utmi_rxactive_q;

reg [1:0]           utmi_linestate_q;

reg [7:0]           utmi_data_q;

reg                 cmd_wr_q;

localparam REG_FUNC_CTRL = 8'h84;

localparam REG_OTG_CTRL  = 8'h8a;

localparam REG_TRANSMIT  = 8'h40;

localparam REG_WRITE     = 8'h80;

localparam REG_READ      = 8'hC0;

always @ (posedge ulpi_clk60_i or posedge ulpi_rst_i)

begin

    if (ulpi_rst_i)

    begin

        state_q             <= STATE_IDLE;

        ulpi_data_q         <= 8'b0;

        data_q              <= 8'b0;

        ulpi_stp_q          <= 1'b0;

        utmi_rxvalid_q      <= 1'b0;

        utmi_rxerror_q      <= 1'b0;

        utmi_rxactive_q     <= 1'b0;

        utmi_linestate_q    <= 2'b0;

        utmi_data_q         <= 8'b0;

        cmd_wr_q            <= 1'b0;

    end

    else

    begin

        ulpi_stp_q          <= 1'b0;

        utmi_rxvalid_q      <= 1'b0;

        if (!turnaround_w)

        begin

            //-----------------------------------------------------------------

            // Input

            //-----------------------------------------------------------------

            if (ulpi_dir_i)

            begin

                utmi_rxvalid_q  <= ulpi_nxt_i;

                utmi_data_q     <= ulpi_data_i;

                // No valid data, extract phy status 

                if (!ulpi_nxt_i)

                begin

                    utmi_linestate_q <= ulpi_data_i[1:0];

                    case (ulpi_data_i[5:4])

                    2'b00:

                    begin

                        utmi_rxactive_q <= 1'b0;

                        utmi_rxerror_q  <= 1'b0;

                    end

                    2'b01:

                    begin

                        utmi_rxactive_q <= 1'b1;

                        utmi_rxerror_q  <= 1'b0;

                    end

                    2'b11:

                    begin

                        utmi_rxactive_q <= 1'b1;

                        utmi_rxerror_q  <= 1'b1;

                    end

                    default:

                        ; // HOST_DISCONNECTED

                    endcase

                end

                // RxValid (so force RxActive)

                else

                    utmi_rxactive_q <= 1'b1;

            end

            //-----------------------------------------------------------------

            // Output

            //-----------------------------------------------------------------

            else

            begin

                // IDLE: Pending mode update

                if ((state_q == STATE_IDLE) && mode_update_q)

                begin

                    data_q      <= {1'b0, 1'b1, phy_reset_q, opmode_q, termselect_q, xcvrselect_q};

                    ulpi_data_q <= REG_FUNC_CTRL;

                    state_q     <= STATE_CMD;

                    cmd_wr_q    <= 1'b1;

                end

                // IDLE: Pending OTG control update

                else if ((state_q == STATE_IDLE) && otg_update_q)

                begin

                    data_q      <= {5'b0, dmpulldown_q, dppulldown_q, 1'b0};

                    ulpi_data_q <= REG_OTG_CTRL;

                    state_q     <= STATE_CMD;

                    cmd_wr_q    <= 1'b1;

                end

                // IDLE: Pending transmit

                else if ((state_q == STATE_IDLE) && utmi_tx_ready_w)

                begin

                    ulpi_data_q <= REG_TRANSMIT | {4'b0, utmi_tx_data_w[3:0]};

                    state_q     <= STATE_DATA;

                    cmd_wr_q    <= 1'b0;

                end

                // Command

                else if ((state_q == STATE_CMD) && ulpi_nxt_i)

                begin

                    state_q     <= STATE_DATA;

                    ulpi_data_q <= data_q;

                end

                // Data

                else if (state_q == STATE_DATA && ulpi_nxt_i)

                begin

                    // End of packet

                    if (!utmi_tx_ready_w || cmd_wr_q)

                    begin

                        state_q       <= STATE_IDLE;

                        ulpi_data_q   <= 8'b0;  // IDLE

                        ulpi_stp_q    <= 1'b1;

                        cmd_wr_q      <= 1'b0;

                    end

                    else

                    begin

                        state_q        <= STATE_DATA;

                        ulpi_data_q    <= utmi_tx_data_w;

                    end

                end

            end

        end

    end

end

// Accept from buffer

assign utmi_tx_accept_w = ((state_q == STATE_IDLE) && !(mode_update_q || otg_update_q || turnaround_w) && !ulpi_dir_i) ||

                          (state_q == STATE_DATA && ulpi_nxt_i && !ulpi_dir_i && !cmd_wr_q);

//-----------------------------------------------------------------

// Assignments

//-----------------------------------------------------------------

// ULPI Interface

assign ulpi_data_o          = ulpi_data_q;

assign ulpi_stp_o           = ulpi_stp_q;

// UTMI Interface

assign utmi_linestate_o     = utmi_linestate_q;

assign utmi_data_o          = utmi_data_q;

assign utmi_rxerror_o       = utmi_rxerror_q;

assign utmi_rxactive_o      = utmi_rxactive_q;

assign utmi_rxvalid_o       = utmi_rxvalid_q;

endmodule