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/*
* pkt_filter.v
*
* Copyright (C) 2018, 2019 Mind Chasers Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* function: packet filter / CAM wrapper with keep / drop logic
*
*/
`timescale 1ns /10ps
module pkt_filter #(parameter DEPTH = 4,
parameter DEPTHW = 2,
parameter WIDTH = 32)
(
input rstn,
input clk,
// input for programming
input sel,
input we,
input [DEPTHW+1:0] addr,
input [7:0] d_in,
// registered data
input[7:0] rx_data_m1,
input[7:0] rx_data_m2,
input[7:0] rx_data_m3,
input[7:0] rx_data_m4,
// filter
input new_frame, // assert for each new frame to reset state machines
input block,
input invert,
input trigger,
output reg keep
);
reg trigger_m1;
/* trigger_m1 is used to sync the CAM search with testing the results below */
always @(posedge clk or negedge rstn)
if (!rstn)
trigger_m1 <= 1'b0;
else
trigger_m1 <= trigger;
/* keep is a one shot */
always @(posedge clk or negedge rstn)
if (!rstn)
keep <= 1'b0;
else if (trigger_m1)
if ( block )
keep <= 1'b0;
else if ( !invert )
keep <= match;
else begin
keep <= ~match;
end
else
keep <= 1'b0;
cam #(.DEPTH(DEPTH), .DEPTHW(DEPTHW), .WIDTH(WIDTH)) cam_0(
.rstn( rstn ),
.clk( clk ),
// input for programming
.sel( sel ),
.we( we ),
.addr( addr ),
.d_in( d_in ),
// cam action
.search( trigger ),
.search_address( { rx_data_m4, rx_data_m3, rx_data_m2, rx_data_m1 } ),
.match( match )
);
endmodule
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