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//
// Copyright 2013 Ettus Research LLC
//
// This program is free software: 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 3 of the License, or
// (at your option) any later version.
//
// This program 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 program. If not, see <http://www.gnu.org/licenses/>.
//
module cvita_dechunker # (
parameter PAD_VALUE = 64'hFFFFFFFF_FFFFFFFF
) (
input clk,
input reset,
input clear,
input [15:0] frame_size,
input [63:0] i_tdata,
input i_tvalid,
output i_tready,
output [63:0] o_tdata,
output o_tlast,
output o_tvalid,
input o_tready,
output error
);
localparam ST_HEADER = 2'd0;
localparam ST_DATA = 2'd1;
localparam ST_PADDING = 2'd2;
localparam ST_ERROR = 2'd3;
reg [1:0] state;
reg [15:0] frame_rem, pkt_rem;
wire i_tlast;
wire [15:0] cvita_len_ceil = i_tdata[47:32] + 7;
wire [15:0] axi_len = {3'b000, cvita_len_ceil[15:3]};
always @(posedge clk) begin
if (reset | clear) begin
state <= ST_HEADER;
frame_rem <= 16'd0;
pkt_rem <= 16'd0;
end else if (i_tvalid & i_tready) begin
case (state)
ST_HEADER: begin
if (axi_len > frame_size)
state <= ST_ERROR;
else if (~o_tlast)
state <= ST_DATA;
else
state <= ST_PADDING;
frame_rem <= frame_size - 16'd1;
pkt_rem <= axi_len - 16'd1;
end
ST_DATA: begin
if (o_tlast) begin
state <= i_tlast ? ST_HEADER : ST_PADDING;
pkt_rem <= 16'd0;
end else begin
state <= ST_DATA;
pkt_rem <= pkt_rem - 16'd1;
end
frame_rem <= frame_rem - 16'd1;
end
ST_PADDING: begin
if (i_tlast) begin
state <= ST_HEADER;
frame_rem <= 16'd0;
end else begin
state <= ST_PADDING;
frame_rem <= frame_rem - 16'd1;
end
end
endcase
end
end
assign i_tready = o_tready | (state == ST_PADDING);
assign i_tlast = (frame_rem == 16'd1); //Temp signal
assign o_tvalid = i_tvalid & (state != ST_PADDING);
assign o_tlast = (pkt_rem != 0) ? (pkt_rem == 16'd1) : (axi_len == 16'd1);
assign o_tdata = i_tdata;
assign error = (state == ST_ERROR);
endmodule // cvita_dechunker
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