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|
//
// Copyright 2021 Ettus Research, a National Instruments Brand
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
// Module: axi_mux
//
// Description:
//
// Takes arbitrary number of AXI streams and merges them to into a single
// output channel. Bubble cycles are inserted after each packet.
//
// Parameters:
//
// PRIO : Controls the arbitration scheme.
// 0 - Round-robin
// 1 - Priority (lower number ports get priority)
// WIDTH : Width of each AXI-Stream (width of TDATA).
// PRE_FIFO_SIZE : Log2 of the input buffer FIFO. Set to 0 for no FIFO.
// POST_FIFO_SIZE : Log2 of the output buffer FIFO. Set to 0 for no FIFO.
// SIZE : Number of input ports to the multiplexer.
//
`default_nettype none
module axi_mux #(
parameter PRIO = 0,
parameter WIDTH = 64,
parameter PRE_FIFO_SIZE = 0,
parameter POST_FIFO_SIZE = 0,
parameter SIZE = 4
) (
input wire clk,
input wire reset,
input wire clear,
// Input streams
input wire [WIDTH*SIZE-1:0] i_tdata,
input wire [ SIZE-1:0] i_tlast,
input wire [ SIZE-1:0] i_tvalid,
output wire [ SIZE-1:0] i_tready,
// Single output stream
output wire [ WIDTH-1:0] o_tdata,
output wire o_tlast,
output wire o_tvalid,
input wire o_tready
);
wire [WIDTH*SIZE-1:0] i_tdata_int;
wire [ SIZE-1:0] i_tlast_int;
wire [ SIZE-1:0] i_tvalid_int;
wire [ SIZE-1:0] i_tready_int;
wire [WIDTH-1:0] o_tdata_int;
wire o_tlast_int;
wire o_tvalid_int;
wire o_tready_int;
reg [$clog2(SIZE)-1:0] st_port;
reg st_active;
//---------------------------------------------------------------------------
// Input FIFO
//---------------------------------------------------------------------------
genvar n;
generate
if (PRE_FIFO_SIZE == 0) begin : gen_no_pre_fifo
assign i_tdata_int = i_tdata;
assign i_tlast_int = i_tlast;
assign i_tvalid_int = i_tvalid;
assign i_tready = i_tready_int;
end else begin : gen_pre_fifo
for (n = 0; n < SIZE; n = n + 1) begin
axi_fifo #(
.WIDTH(WIDTH+1 ),
.SIZE (PRE_FIFO_SIZE)
) axi_fifo (
.clk (clk ),
.reset (reset ),
.clear (clear ),
.i_tdata ({i_tlast[n],i_tdata[WIDTH*(n+1)-1:WIDTH*n]} ),
.i_tvalid(i_tvalid[n] ),
.i_tready(i_tready[n] ),
.o_tdata ({i_tlast_int[n],i_tdata_int[WIDTH*(n+1)-1:WIDTH*n]}),
.o_tvalid(i_tvalid_int[n] ),
.o_tready(i_tready_int[n] ),
.space ( ),
.occupied( )
);
end
end
endgenerate
//---------------------------------------------------------------------------
// Multiplexer Logic
//---------------------------------------------------------------------------
always @(posedge clk) begin
if (reset) begin
st_port <= 0;
st_active <= 1'b0;
end else begin
if (st_active) begin
if (o_tlast_int & o_tvalid_int & o_tready_int) begin
st_active <= 1'b0;
if ((PRIO != 0) | (st_port == (SIZE-1))) begin
st_port <= 0;
end else begin
st_port <= st_port + 1;
end
end
end else begin
if (i_tvalid_int[st_port]) begin
st_active <= 1'b1;
end else begin
if (st_port == (SIZE-1)) begin
st_port <= 0;
end else begin
st_port <= st_port + 1;
end
end
end
end
end
genvar i;
generate
for (i=0; i<SIZE; i=i+1) begin : gen_tready
assign i_tready_int[i] = st_active & o_tready_int & (st_port == i);
end
endgenerate
assign o_tvalid_int = st_active & i_tvalid_int[st_port];
assign o_tlast_int = i_tlast_int[st_port];
genvar j;
generate
for (j=0; j<WIDTH; j=j+1) begin : gen_tdata
assign o_tdata_int[j] = i_tdata_int[st_port*WIDTH+j];
end
endgenerate
//---------------------------------------------------------------------------
// Output FIFO
//---------------------------------------------------------------------------
generate
if (POST_FIFO_SIZE == 0) begin
assign o_tdata = o_tdata_int;
assign o_tlast = o_tlast_int;
assign o_tvalid = o_tvalid_int;
assign o_tready_int = o_tready;
end else begin
axi_fifo #(
.WIDTH(WIDTH+1 ),
.SIZE (POST_FIFO_SIZE)
) axi_fifo (
.clk (clk ),
.reset (reset ),
.clear (clear ),
.i_tdata ({o_tlast_int,o_tdata_int}),
.i_tvalid(o_tvalid_int ),
.i_tready(o_tready_int ),
.o_tdata ({o_tlast,o_tdata} ),
.o_tvalid(o_tvalid ),
.o_tready(o_tready ),
.space ( ),
.occupied( )
);
end
endgenerate
endmodule
`default_nettype wire
|
