module axis_fifo_adapter #
(
    // FIFO depth in words
    // KEEP_WIDTH words per cycle if KEEP_ENABLE set
    // Rounded up to nearest power of 2 cycles
    parameter DEPTH = 4096,
    // Width of input AXI stream interface in bits
    parameter S_DATA_WIDTH = 8,
    // Propagate tkeep signal on input interface
    // If disabled, tkeep assumed to be 1'b1
    parameter S_KEEP_ENABLE = (S_DATA_WIDTH>8),
    // tkeep signal width (words per cycle) on input interface
    parameter S_KEEP_WIDTH = ((S_DATA_WIDTH+7)/8),
    // Width of output AXI stream interface in bits
    parameter M_DATA_WIDTH = 8,
    // Propagate tkeep signal on output interface
    // If disabled, tkeep assumed to be 1'b1
    parameter M_KEEP_ENABLE = (M_DATA_WIDTH>8),
    // tkeep signal width (words per cycle) on output interface
    parameter M_KEEP_WIDTH = ((M_DATA_WIDTH+7)/8),
    // Propagate tid signal
    parameter ID_ENABLE = 0,
    // tid signal width
    parameter ID_WIDTH = 8,
    // Propagate tdest signal
    parameter DEST_ENABLE = 0,
    // tdest signal width
    parameter DEST_WIDTH = 8,
    // Propagate tuser signal
    parameter USER_ENABLE = 1,
    // tuser signal width
    parameter USER_WIDTH = 1,
    // number of RAM pipeline registers in FIFO
    parameter RAM_PIPELINE = 1,
    // use output FIFO
    // When set, the RAM read enable and pipeline clock enables are removed
    parameter OUTPUT_FIFO_ENABLE = 0,
    // Frame FIFO mode - operate on frames instead of cycles
    // When set, m_axis_tvalid will not be deasserted within a frame
    // Requires LAST_ENABLE set
    parameter FRAME_FIFO = 0,
    // tuser value for bad frame marker
    parameter USER_BAD_FRAME_VALUE = 1'b1,
    // tuser mask for bad frame marker
    parameter USER_BAD_FRAME_MASK = 1'b1,
    // Drop frames larger than FIFO
    // Requires FRAME_FIFO set
    parameter DROP_OVERSIZE_FRAME = FRAME_FIFO,
    // Drop frames marked bad
    // Requires FRAME_FIFO and DROP_OVERSIZE_FRAME set
    parameter DROP_BAD_FRAME = 0,
    // Drop incoming frames when full
    // When set, s_axis_tready is always asserted
    // Requires FRAME_FIFO and DROP_OVERSIZE_FRAME set
    parameter DROP_WHEN_FULL = 0
)
(
    input  wire                     clk,
    input  wire                     rst,

    /*
     * AXI input
     */
    input  wire [S_DATA_WIDTH-1:0]  s_axis_tdata,
    input  wire [S_KEEP_WIDTH-1:0]  s_axis_tkeep,
    input  wire                     s_axis_tvalid,
    output wire                     s_axis_tready,
    input  wire                     s_axis_tlast,
    input  wire [ID_WIDTH-1:0]      s_axis_tid,
    input  wire [DEST_WIDTH-1:0]    s_axis_tdest,
    input  wire [USER_WIDTH-1:0]    s_axis_tuser,

    /*
     * AXI output
     */
    output wire [M_DATA_WIDTH-1:0]  m_axis_tdata,
    output wire [M_KEEP_WIDTH-1:0]  m_axis_tkeep,
    output wire                     m_axis_tvalid,
    input  wire                     m_axis_tready,
    output wire                     m_axis_tlast,
    output wire [ID_WIDTH-1:0]      m_axis_tid,
    output wire [DEST_WIDTH-1:0]    m_axis_tdest,
    output wire [USER_WIDTH-1:0]    m_axis_tuser,

    /*
     * Status
     */
    output wire                     status_overflow,
    output wire                     status_bad_frame,
    output wire                     status_good_frame
);

// force keep width to 1 when disabled
parameter S_KEEP_WIDTH_INT = S_KEEP_ENABLE ? S_KEEP_WIDTH : 1;
parameter M_KEEP_WIDTH_INT = M_KEEP_ENABLE ? M_KEEP_WIDTH : 1;

// bus word sizes (must be identical)
parameter S_DATA_WORD_SIZE = S_DATA_WIDTH / S_KEEP_WIDTH_INT;
parameter M_DATA_WORD_SIZE = M_DATA_WIDTH / M_KEEP_WIDTH_INT;
// output bus is wider
parameter EXPAND_BUS = M_KEEP_WIDTH_INT > S_KEEP_WIDTH_INT;
// total data and keep widths
parameter DATA_WIDTH = EXPAND_BUS ? M_DATA_WIDTH : S_DATA_WIDTH;
parameter KEEP_WIDTH = EXPAND_BUS ? M_KEEP_WIDTH_INT : S_KEEP_WIDTH_INT;

// bus width assertions
initial begin
    if (S_DATA_WORD_SIZE * S_KEEP_WIDTH_INT != S_DATA_WIDTH) begin
        $error("Error: input data width not evenly divisble (instance %m)");
        $finish;
    end

    if (M_DATA_WORD_SIZE * M_KEEP_WIDTH_INT != M_DATA_WIDTH) begin
        $error("Error: output data width not evenly divisble (instance %m)");
        $finish;
    end

    if (S_DATA_WORD_SIZE != M_DATA_WORD_SIZE) begin
        $error("Error: word size mismatch (instance %m)");
        $finish;
    end
end

wire [DATA_WIDTH-1:0]  pre_fifo_axis_tdata;
wire [KEEP_WIDTH-1:0]  pre_fifo_axis_tkeep;
wire                   pre_fifo_axis_tvalid;
wire                   pre_fifo_axis_tready;
wire                   pre_fifo_axis_tlast;
wire [ID_WIDTH-1:0]    pre_fifo_axis_tid;
wire [DEST_WIDTH-1:0]  pre_fifo_axis_tdest;
wire [USER_WIDTH-1:0]  pre_fifo_axis_tuser;

wire [DATA_WIDTH-1:0]  post_fifo_axis_tdata;
wire [KEEP_WIDTH-1:0]  post_fifo_axis_tkeep;
wire                   post_fifo_axis_tvalid;
wire                   post_fifo_axis_tready;
wire                   post_fifo_axis_tlast;
wire [ID_WIDTH-1:0]    post_fifo_axis_tid;
wire [DEST_WIDTH-1:0]  post_fifo_axis_tdest;
wire [USER_WIDTH-1:0]  post_fifo_axis_tuser;

generate

if (M_KEEP_WIDTH_INT == S_KEEP_WIDTH_INT) begin

    // same width, no adapter needed

    assign pre_fifo_axis_tdata = s_axis_tdata;
    assign pre_fifo_axis_tkeep = s_axis_tkeep;
    assign pre_fifo_axis_tvalid = s_axis_tvalid;
    assign s_axis_tready = pre_fifo_axis_tready;
    assign pre_fifo_axis_tlast = s_axis_tlast;
    assign pre_fifo_axis_tid = s_axis_tid;
    assign pre_fifo_axis_tdest = s_axis_tdest;
    assign pre_fifo_axis_tuser = s_axis_tuser;

    assign m_axis_tdata = post_fifo_axis_tdata;
    assign m_axis_tkeep = post_fifo_axis_tkeep;
    assign m_axis_tvalid = post_fifo_axis_tvalid;
    assign post_fifo_axis_tready = m_axis_tready;
    assign m_axis_tlast = post_fifo_axis_tlast;
    assign m_axis_tid = post_fifo_axis_tid;
    assign m_axis_tdest = post_fifo_axis_tdest;
    assign m_axis_tuser = post_fifo_axis_tuser;

end else if (EXPAND_BUS) begin

    // output wider, adapt width before FIFO

    axis_adapter #(
        .S_DATA_WIDTH(S_DATA_WIDTH),
        .S_KEEP_ENABLE(S_KEEP_ENABLE),
        .S_KEEP_WIDTH(S_KEEP_WIDTH),
        .M_DATA_WIDTH(M_DATA_WIDTH),
        .M_KEEP_ENABLE(M_KEEP_ENABLE),
        .M_KEEP_WIDTH(M_KEEP_WIDTH),
        .ID_ENABLE(ID_ENABLE),
        .ID_WIDTH(ID_WIDTH),
        .DEST_ENABLE(DEST_ENABLE),
        .DEST_WIDTH(DEST_WIDTH),
        .USER_ENABLE(USER_ENABLE),
        .USER_WIDTH(USER_WIDTH)
    )
    adapter_inst (
        .clk(clk),
        .rst(rst),
        // AXI input
        .s_axis_tdata(s_axis_tdata),
        .s_axis_tkeep(s_axis_tkeep),
        .s_axis_tvalid(s_axis_tvalid),
        .s_axis_tready(s_axis_tready),
        .s_axis_tlast(s_axis_tlast),
        .s_axis_tid(s_axis_tid),
        .s_axis_tdest(s_axis_tdest),
        .s_axis_tuser(s_axis_tuser),
        // AXI output
        .m_axis_tdata(pre_fifo_axis_tdata),
        .m_axis_tkeep(pre_fifo_axis_tkeep),
        .m_axis_tvalid(pre_fifo_axis_tvalid),
        .m_axis_tready(pre_fifo_axis_tready),
        .m_axis_tlast(pre_fifo_axis_tlast),
        .m_axis_tid(pre_fifo_axis_tid),
        .m_axis_tdest(pre_fifo_axis_tdest),
        .m_axis_tuser(pre_fifo_axis_tuser)
    );

    assign m_axis_tdata = post_fifo_axis_tdata;
    assign m_axis_tkeep = post_fifo_axis_tkeep;
    assign m_axis_tvalid = post_fifo_axis_tvalid;
    assign post_fifo_axis_tready = m_axis_tready;
    assign m_axis_tlast = post_fifo_axis_tlast;
    assign m_axis_tid = post_fifo_axis_tid;
    assign m_axis_tdest = post_fifo_axis_tdest;
    assign m_axis_tuser = post_fifo_axis_tuser;
    
end else begin

    // input wider, adapt width after FIFO
    
    assign pre_fifo_axis_tdata = s_axis_tdata;
    assign pre_fifo_axis_tkeep = s_axis_tkeep;
    assign pre_fifo_axis_tvalid = s_axis_tvalid;
    assign s_axis_tready = pre_fifo_axis_tready;
    assign pre_fifo_axis_tlast = s_axis_tlast;
    assign pre_fifo_axis_tid = s_axis_tid;
    assign pre_fifo_axis_tdest = s_axis_tdest;
    assign pre_fifo_axis_tuser = s_axis_tuser;

    axis_adapter #(
        .S_DATA_WIDTH(S_DATA_WIDTH),
        .S_KEEP_ENABLE(S_KEEP_ENABLE),
        .S_KEEP_WIDTH(S_KEEP_WIDTH),
        .M_DATA_WIDTH(M_DATA_WIDTH),
        .M_KEEP_ENABLE(M_KEEP_ENABLE),
        .M_KEEP_WIDTH(M_KEEP_WIDTH),
        .ID_ENABLE(ID_ENABLE),
        .ID_WIDTH(ID_WIDTH),
        .DEST_ENABLE(DEST_ENABLE),
        .DEST_WIDTH(DEST_WIDTH),
        .USER_ENABLE(USER_ENABLE),
        .USER_WIDTH(USER_WIDTH)
    )
    adapter_inst (
        .clk(clk),
        .rst(rst),
        // AXI input
        .s_axis_tdata(post_fifo_axis_tdata),
        .s_axis_tkeep(post_fifo_axis_tkeep),
        .s_axis_tvalid(post_fifo_axis_tvalid),
        .s_axis_tready(post_fifo_axis_tready),
        .s_axis_tlast(post_fifo_axis_tlast),
        .s_axis_tid(post_fifo_axis_tid),
        .s_axis_tdest(post_fifo_axis_tdest),
        .s_axis_tuser(post_fifo_axis_tuser),
        // AXI output
        .m_axis_tdata(m_axis_tdata),
        .m_axis_tkeep(m_axis_tkeep),
        .m_axis_tvalid(m_axis_tvalid),
        .m_axis_tready(m_axis_tready),
        .m_axis_tlast(m_axis_tlast),
        .m_axis_tid(m_axis_tid),
        .m_axis_tdest(m_axis_tdest),
        .m_axis_tuser(m_axis_tuser)
    );

end

endgenerate

axis_fifo #(
    .DEPTH(DEPTH),
    .DATA_WIDTH(DATA_WIDTH),
    .KEEP_ENABLE(EXPAND_BUS ? M_KEEP_ENABLE : S_KEEP_ENABLE),
    .KEEP_WIDTH(KEEP_WIDTH),
    .LAST_ENABLE(1),
    .ID_ENABLE(ID_ENABLE),
    .ID_WIDTH(ID_WIDTH),
    .DEST_ENABLE(DEST_ENABLE),
    .DEST_WIDTH(DEST_WIDTH),
    .USER_ENABLE(USER_ENABLE),
    .USER_WIDTH(USER_WIDTH),
    .RAM_PIPELINE(RAM_PIPELINE),
    .OUTPUT_FIFO_ENABLE(OUTPUT_FIFO_ENABLE),
    .FRAME_FIFO(FRAME_FIFO),
    .USER_BAD_FRAME_VALUE(USER_BAD_FRAME_VALUE),
    .USER_BAD_FRAME_MASK(USER_BAD_FRAME_MASK),
    .DROP_OVERSIZE_FRAME(DROP_OVERSIZE_FRAME),
    .DROP_BAD_FRAME(DROP_BAD_FRAME),
    .DROP_WHEN_FULL(DROP_WHEN_FULL)
)
fifo_inst (
    .clk(clk),
    .rst(rst),
    // AXI input
    .s_axis_tdata(pre_fifo_axis_tdata),
    .s_axis_tkeep(pre_fifo_axis_tkeep),
    .s_axis_tvalid(pre_fifo_axis_tvalid),
    .s_axis_tready(pre_fifo_axis_tready),
    .s_axis_tlast(pre_fifo_axis_tlast),
    .s_axis_tid(pre_fifo_axis_tid),
    .s_axis_tdest(pre_fifo_axis_tdest),
    .s_axis_tuser(pre_fifo_axis_tuser),
    // AXI output
    .m_axis_tdata(post_fifo_axis_tdata),
    .m_axis_tkeep(post_fifo_axis_tkeep),
    .m_axis_tvalid(post_fifo_axis_tvalid),
    .m_axis_tready(post_fifo_axis_tready),
    .m_axis_tlast(post_fifo_axis_tlast),
    .m_axis_tid(post_fifo_axis_tid),
    .m_axis_tdest(post_fifo_axis_tdest),
    .m_axis_tuser(post_fifo_axis_tuser),
    // Status
    .status_overflow(status_overflow),
    .status_bad_frame(status_bad_frame),
    .status_good_frame(status_good_frame)
);

endmodule