//
// Copyright 2021 Ettus Research, a National Instruments Brand
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
// Module: chdr_resize
//
// Description:
//
// Takes a CHDR packet data stream and converts it from one CHDR width to a
// different CHDR width. It can also do CHDR width conversion without
// changing the bus width, if the bus width is the same size as the smaller
// CHDR width.
//
// For example, to convert from a 64-bit CHDR_W to a 256-bit CHDR_W, you
// would set I_CHDR_W to 64 and O_CHDR_W to 256 (by default, I_DATA_W will be
// set to 64 and O_DATA_W will be set to 256).
//
// But you could also convert from 64-bit CHDR to 256-bit CHDR while keeping
// the bus width at 64 bits. In this case you would set I_CHDR_W to 64 and
// O_CHDR_W to 256, but set both I_DATA_W and O_DATA_W to 64.
//
// There are some restrictions, including the requirement that I_CHDR_W ==
// I_DATA_W or O_CHDR_W == O_DATA_W, and that MIN(I_DATA_W, O_DATA_W) ==
// MIN(I_CHDR_W, O_CHDR_W). Basically, it can't do CHDR width conversion
// where the smaller CHDR width is smaller than the bus width(s). For
// example, you could not do conversion from 64-bit to 256-bit CHDR with
// input and output bus widths of 256.
//
// TUSER is supported, but is not resized. TUSER is sampled along with the
// first word of the input packet and is assumed to be the same for the
// duration of the packet.
//
// Also, note that packets with different CHDR_W have a different maximum
// number of metadata bytes. This module repacks the metadata in
// little-endian order in the new word size. If there is too much metadata
// for a smaller CHDR_W packet, the extra data will be discarded.
//
// Parameters:
//
// I_CHDR_W : CHDR_W for the input data stream on i_chdr.
// O_CHDR_W : CHDR_W for the output data stream on o_chdr.
// I_DATA_W : Bus width for i_chdr_tdata.
// O_DATA_W : Bus width for o_chdr_tdata.
// USER_W : Width for i_chdr_tuser and o_chdr_tuser.
// PIPELINE : Indicates whether to add pipeline stages to the input and/or
// output. This can be: "NONE", "IN", "OUT", or "INOUT".
//
`default_nettype none
module chdr_resize #(
parameter I_CHDR_W = 64,
parameter O_CHDR_W = 512,
parameter I_DATA_W = I_CHDR_W,
parameter O_DATA_W = O_CHDR_W,
parameter USER_W = 1,
parameter PIPELINE = "NONE"
) (
input wire clk,
input wire rst,
// Input
input wire [I_DATA_W-1:0] i_chdr_tdata,
input wire [ USER_W-1:0] i_chdr_tuser,
input wire i_chdr_tlast,
input wire i_chdr_tvalid,
output wire i_chdr_tready,
// Input
output wire [O_DATA_W-1:0] o_chdr_tdata,
output wire [ USER_W-1:0] o_chdr_tuser,
output wire o_chdr_tlast,
output wire o_chdr_tvalid,
input wire o_chdr_tready
);
`define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
// Determine the bus width of the CHDR converter, which is always the smaller
// bus width of the input and output.
localparam CONVERT_W = `MIN(I_DATA_W, O_DATA_W);
// Determine if we need the bus down-sizer
localparam DO_DOWNSIZE = (I_DATA_W > O_DATA_W);
// Determine if we need the CHDR width converter
localparam DO_CONVERT = (I_CHDR_W != O_CHDR_W);
// Determine if we need the bus up-sizer
localparam DO_UPSIZE = (I_DATA_W < O_DATA_W);
// Determine the pipeline settings. We want pipeline stages on the input
// and/or output, depending on the PIPELINE parameter, as well as between the
// up-sizer and converter, and between the converter and down-sizer, any of
// which may or may not be present. We don't, however, want back-to-back
// pipeline stages (e.g., on the output of the down-sizer and the input to
// the converter). If both an up/down-sizer and converter are used, the
// settings below will turn on the adjacent pipeline stage in the converter
// and turn off the corresponding pipeline stage in the up/down-sizer.
localparam DOWNSIZE_PIPELINE =
(PIPELINE == "IN" && DO_CONVERT) ? "IN" :
(PIPELINE == "IN" && !DO_CONVERT) ? "IN" :
(PIPELINE == "INOUT" && DO_CONVERT) ? "IN" :
(PIPELINE == "INOUT" && !DO_CONVERT) ? "INOUT" :
(PIPELINE == "OUT" && DO_CONVERT) ? "NONE" :
(PIPELINE == "OUT" && !DO_CONVERT) ? "OUT" :
"NONE" ;
localparam CONVERT_PIPELINE =
(PIPELINE == "IN" && DO_DOWNSIZE) ? "IN" :
(PIPELINE == "IN" && DO_UPSIZE ) ? "INOUT" :
(PIPELINE == "IN" /* neither */) ? "IN" :
(PIPELINE == "INOUT" && DO_DOWNSIZE) ? "INOUT" :
(PIPELINE == "INOUT" && DO_UPSIZE ) ? "INOUT" :
(PIPELINE == "INOUT" /* neither */) ? "INOUT" :
(PIPELINE == "OUT" && DO_DOWNSIZE) ? "INOUT" :
(PIPELINE == "OUT" && DO_UPSIZE ) ? "OUT" :
(PIPELINE == "OUT" /* neither */) ? "OUT" :
"NONE" ;
localparam UPSIZE_PIPELINE =
(PIPELINE == "IN" && DO_CONVERT) ? "NONE" :
(PIPELINE == "IN" && !DO_CONVERT) ? "IN" :
(PIPELINE == "INOUT" && DO_CONVERT) ? "OUT" :
(PIPELINE == "INOUT" && !DO_CONVERT) ? "INOUT" :
(PIPELINE == "OUT" && DO_CONVERT) ? "OUT" :
(PIPELINE == "OUT" && !DO_CONVERT) ? "OUT" :
"NONE" ;
generate
//-------------------------------------------------------------------------
// Check Parameters
//-------------------------------------------------------------------------
if (!(
// All widths must be valid CHDR widths (at least 64 and powers of 2)
(2**$clog2(I_CHDR_W) == I_CHDR_W) &&
(2**$clog2(O_CHDR_W) == O_CHDR_W) &&
(2**$clog2(I_DATA_W) == I_DATA_W) &&
(2**$clog2(O_DATA_W) == O_DATA_W) &&
(I_CHDR_W >= 64) &&
(O_CHDR_W >= 64) &&
(I_DATA_W >= 64) &&
(O_DATA_W >= 64) &&
// The converter width must match the smaller bus width. It doesn't work
// on buses wider than the CHDR width.
(CONVERT_W == `MIN(I_CHDR_W, O_CHDR_W))
)) begin : gen_error
ERROR__Invalid_CHDR_or_data_width_parameters();
end
//-------------------------------------------------------------------------
// TUSER Data Path
//-------------------------------------------------------------------------
//
// Sample TUSER at the beginning of the input packet and output it for the
// duration of the output packet.
//
//-------------------------------------------------------------------------
if (DO_DOWNSIZE || DO_UPSIZE || DO_CONVERT || PIPELINE == "INOUT") begin : gen_tuser_buffer
if (!DO_DOWNSIZE && !DO_UPSIZE && DO_CONVERT && PIPELINE == "NONE") begin : gen_tuser_reg
// In this case, there's a combinatorial path from i_chdr to o_chdr, so
// we can't use a FIFO to buffer TUSER.
// Track start of packet on o_chdr
reg o_chdr_sop = 1;
always @(posedge clk) begin
if (rst) begin
o_chdr_sop <= 1;
end else if (o_chdr_tvalid && o_chdr_tready) begin
o_chdr_sop <= o_chdr_tlast;
end
end
reg [USER_W-1:0] o_tuser_reg;
always @(posedge clk) begin
if (rst) begin
o_tuser_reg <= {USER_W{1'bX}};
end else if (o_chdr_tvalid && o_chdr_tready && o_chdr_sop) begin
o_tuser_reg <= i_chdr_tuser;
end
end
// Pass through TUSER for first word in the packet, then use a holding
// register for the rest of the packet.
assign o_chdr_tuser = (o_chdr_sop) ? i_chdr_tuser : o_tuser_reg;
end else begin : gen_tuser_fifo
// In this case we use a FIFO to buffer TUSER.
// Track start of packet on i_chdr
reg i_chdr_sop = 1;
always @(posedge clk) begin
if (rst) begin
i_chdr_sop <= 1;
end else if (i_chdr_tvalid && i_chdr_tready) begin
i_chdr_sop <= i_chdr_tlast;
end
end
axi_fifo_short #(
.WIDTH (USER_W)
) axi_fifo_short_i (
.clk (clk),
.reset (rst),
.clear (1'b0),
.i_tdata (i_chdr_tuser),
.i_tvalid (i_chdr_tvalid && i_chdr_tready && i_chdr_sop),
.i_tready (),
.o_tdata (o_chdr_tuser),
.o_tvalid (),
.o_tready (o_chdr_tready && o_chdr_tvalid && o_chdr_tlast),
.space (),
.occupied ()
);
end
end else begin : gen_tuser_pass_through
// In this case there's no logic on the data path, so we can pass TUSER
// through directly.
assign o_chdr_tuser = i_chdr_tuser;
end
//-------------------------------------------------------------------------
// Down-Size Input Bus Width
//-------------------------------------------------------------------------
wire [CONVERT_W-1:0] resized_tdata;
wire resized_tlast;
wire resized_tvalid;
wire resized_tready;
if (DO_DOWNSIZE) begin : gen_bus_downsize
axis_width_conv #(
.WORD_W (CONVERT_W),
.IN_WORDS (I_DATA_W / CONVERT_W),
.OUT_WORDS (1),
.SYNC_CLKS (1),
.PIPELINE (DOWNSIZE_PIPELINE)
) axis_width_conv_i (
.s_axis_aclk (clk),
.s_axis_rst (rst),
.s_axis_tdata (i_chdr_tdata),
.s_axis_tkeep ({(I_DATA_W / CONVERT_W){1'b1}}),
.s_axis_tlast (i_chdr_tlast),
.s_axis_tvalid (i_chdr_tvalid),
.s_axis_tready (i_chdr_tready),
.m_axis_aclk (clk),
.m_axis_rst (rst),
.m_axis_tdata (resized_tdata),
.m_axis_tkeep (),
.m_axis_tlast (resized_tlast),
.m_axis_tvalid (resized_tvalid),
.m_axis_tready (resized_tready)
);
end else begin : gen_no_bus_downsize
assign resized_tdata = i_chdr_tdata;
assign resized_tlast = i_chdr_tlast;
assign resized_tvalid = i_chdr_tvalid;
assign i_chdr_tready = resized_tready;
end
//-------------------------------------------------------------------------
// CHDR Width Protocol Conversion
//-------------------------------------------------------------------------
wire [CONVERT_W-1:0] converted_tdata;
wire converted_tlast;
wire converted_tvalid;
wire converted_tready;
if (DO_CONVERT) begin : gen_convert
if (I_CHDR_W > O_CHDR_W) begin : gen_chdr_convert_down
chdr_convert_down #(
.I_CHDR_W (I_CHDR_W),
.DATA_W (CONVERT_W),
.PIPELINE (CONVERT_PIPELINE)
) chdr_convert_down_i (
.clk (clk),
.rst (rst),
.i_chdr_tdata (resized_tdata),
.i_chdr_tlast (resized_tlast),
.i_chdr_tvalid (resized_tvalid),
.i_chdr_tready (resized_tready),
.o_chdr_tdata (o_chdr_tdata),
.o_chdr_tlast (o_chdr_tlast),
.o_chdr_tvalid (o_chdr_tvalid),
.o_chdr_tready (o_chdr_tready)
);
end else if (I_CHDR_W < O_CHDR_W) begin : gen_chdr_convert_up
chdr_convert_up #(
.DATA_W (CONVERT_W),
.O_CHDR_W (O_CHDR_W),
.PIPELINE (PIPELINE)
) chdr_convert_up_i (
.clk (clk),
.rst (rst),
.i_chdr_tdata (resized_tdata),
.i_chdr_tlast (resized_tlast),
.i_chdr_tvalid (resized_tvalid),
.i_chdr_tready (resized_tready),
.o_chdr_tdata (converted_tdata),
.o_chdr_tlast (converted_tlast),
.o_chdr_tvalid (converted_tvalid),
.o_chdr_tready (converted_tready)
);
end
end else begin : gen_no_convert
if (PIPELINE == "INOUT" && !DO_DOWNSIZE && !DO_UPSIZE) begin : gen_pipeline
// In this case there's no conversion or up-size/down-size, so we're
// just passing the data through unchanged. However, if PIPELINE is set
// to INOUT then we should have a pipeline stage, so we add that here.
axi_fifo_flop2 #(
.WIDTH (1 + CONVERT_W)
) axi_fifo_flop2_i (
.clk (clk),
.reset (rst),
.clear (1'b0),
.i_tdata ({ resized_tlast, resized_tdata }),
.i_tvalid (resized_tvalid),
.i_tready (resized_tready),
.o_tdata ({ converted_tlast, converted_tdata }),
.o_tvalid (converted_tvalid),
.o_tready (converted_tready),
.space (),
.occupied ()
);
end else begin : gen_convert_bypass
assign converted_tdata = resized_tdata;
assign converted_tlast = resized_tlast;
assign converted_tvalid = resized_tvalid;
assign resized_tready = converted_tready;
end
end
//-------------------------------------------------------------------------
// Up-Size Output Bus Width
//-------------------------------------------------------------------------
if (DO_UPSIZE) begin : gen_bus_upsize
axis_width_conv #(
.WORD_W (CONVERT_W),
.IN_WORDS (1),
.OUT_WORDS (O_DATA_W / CONVERT_W),
.SYNC_CLKS (1),
.PIPELINE (UPSIZE_PIPELINE)
) axis_width_conv_i (
.s_axis_aclk (clk),
.s_axis_rst (rst),
.s_axis_tdata (converted_tdata),
.s_axis_tkeep (1'b1),
.s_axis_tlast (converted_tlast),
.s_axis_tvalid (converted_tvalid),
.s_axis_tready (converted_tready),
.m_axis_aclk (clk),
.m_axis_rst (rst),
.m_axis_tdata (o_chdr_tdata),
.m_axis_tkeep (),
.m_axis_tlast (o_chdr_tlast),
.m_axis_tvalid (o_chdr_tvalid),
.m_axis_tready (o_chdr_tready)
);
end else begin : gen_no_bus_upsize
assign o_chdr_tdata = converted_tdata;
assign o_chdr_tlast = converted_tlast;
assign o_chdr_tvalid = converted_tvalid;
assign converted_tready = o_chdr_tready;
end
endgenerate
endmodule
`default_nettype wire