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riffa/fpga/riffa_hdl/rx_port_requester_mux.v
2016-02-09 15:23:37 -08:00

212 lines
6.3 KiB
Verilog

// ----------------------------------------------------------------------
// Copyright (c) 2016, The Regents of the University of California All
// rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
//
// * Neither the name of The Regents of the University of California
// nor the names of its contributors may be used to endorse or
// promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL REGENTS OF THE
// UNIVERSITY OF CALIFORNIA BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
// TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
// USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
// DAMAGE.
// ----------------------------------------------------------------------
//----------------------------------------------------------------------------
// Filename: rx_port_requester.v
// Version: 1.00.a
// Verilog Standard: Verilog-2001
// Description: Issues read requests to the tx_engine for the rx_port
// and sg_list_requester modules in the rx_port. Expects those modules to update
// their address and length values after every request issued. Also expects them
// to update their space available values within 6 cycles of a change to the
// RX_LEN.
// Author: Matt Jacobsen
// History: @mattj: Version 2.0
//-----------------------------------------------------------------------------
`define S_RXPORTREQ_RX_TX 2'b00
`define S_RXPORTREQ_TX_RX 2'b01
`define S_RXPORTREQ_ISSUE 2'b10
`timescale 1ns/1ns
module rx_port_requester_mux (
input RST,
input CLK,
input SG_RX_REQ, // Scatter gather RX read request
input [9:0] SG_RX_LEN, // Scatter gather RX read request length
input [63:0] SG_RX_ADDR, // Scatter gather RX read request address
output SG_RX_REQ_PROC, // Scatter gather RX read request processing
input SG_TX_REQ, // Scatter gather TX read request
input [9:0] SG_TX_LEN, // Scatter gather TX read request length
input [63:0] SG_TX_ADDR, // Scatter gather TX read request address
output SG_TX_REQ_PROC, // Scatter gather TX read request processing
input MAIN_REQ, // Main read request
input [9:0] MAIN_LEN, // Main read request length
input [63:0] MAIN_ADDR, // Main read request address
output MAIN_REQ_PROC, // Main read request processing
output RX_REQ, // Read request
input RX_REQ_ACK, // Read request accepted
output [1:0] RX_REQ_TAG, // Read request data tag
output [63:0] RX_REQ_ADDR, // Read request address
output [9:0] RX_REQ_LEN, // Read request length
output REQ_ACK // Request accepted
);
reg rRxReqAck=0, _rRxReqAck=0;
(* syn_encoding = "user" *)
(* fsm_encoding = "user" *)
reg [1:0] rState=`S_RXPORTREQ_RX_TX, _rState=`S_RXPORTREQ_RX_TX;
reg [9:0] rLen=0, _rLen=0;
reg [63:0] rAddr=64'd0, _rAddr=64'd0;
reg rSgRxAck=0, _rSgRxAck=0;
reg rSgTxAck=0, _rSgTxAck=0;
reg rMainAck=0, _rMainAck=0;
reg rAck=0, _rAck=0;
assign SG_RX_REQ_PROC = rSgRxAck;
assign SG_TX_REQ_PROC = rSgTxAck;
assign MAIN_REQ_PROC = rMainAck;
assign RX_REQ = rState[1]; // S_RXPORTREQ_ISSUE
assign RX_REQ_TAG = {rSgTxAck, rSgRxAck};
assign RX_REQ_ADDR = rAddr;
assign RX_REQ_LEN = rLen;
assign REQ_ACK = rAck;
// Buffer signals that come from outside the rx_port.
always @ (posedge CLK) begin
rRxReqAck <= #1 (RST ? 1'd0 : _rRxReqAck);
end
always @ (*) begin
_rRxReqAck = RX_REQ_ACK;
end
// Handle issuing read requests. Scatter gather requests are processed
// with higher priority than the main channel.
always @ (posedge CLK) begin
rState <= #1 (RST ? `S_RXPORTREQ_RX_TX : _rState);
rLen <= #1 _rLen;
rAddr <= #1 _rAddr;
rSgRxAck <= #1 _rSgRxAck;
rSgTxAck <= #1 _rSgTxAck;
rMainAck <= #1 _rMainAck;
rAck <= #1 _rAck;
end
always @ (*) begin
_rState = rState;
_rLen = rLen;
_rAddr = rAddr;
_rSgRxAck = rSgRxAck;
_rSgTxAck = rSgTxAck;
_rMainAck = rMainAck;
_rAck = rAck;
case (rState)
`S_RXPORTREQ_RX_TX: begin // Wait for a new read request
if (SG_RX_REQ) begin
_rLen = SG_RX_LEN;
_rAddr = SG_RX_ADDR;
_rSgRxAck = 1;
_rAck = 1;
_rState = `S_RXPORTREQ_ISSUE;
end
else if (SG_TX_REQ) begin
_rLen = SG_TX_LEN;
_rAddr = SG_TX_ADDR;
_rSgTxAck = 1;
_rAck = 1;
_rState = `S_RXPORTREQ_ISSUE;
end
else if (MAIN_REQ) begin
_rLen = MAIN_LEN;
_rAddr = MAIN_ADDR;
_rMainAck = 1;
_rAck = 1;
_rState = `S_RXPORTREQ_ISSUE;
end
else begin
_rState = `S_RXPORTREQ_TX_RX;
end
end
`S_RXPORTREQ_TX_RX: begin // Wait for a new read request
if (SG_TX_REQ) begin
_rLen = SG_TX_LEN;
_rAddr = SG_TX_ADDR;
_rSgTxAck = 1;
_rAck = 1;
_rState = `S_RXPORTREQ_ISSUE;
end
else if (SG_RX_REQ) begin
_rLen = SG_RX_LEN;
_rAddr = SG_RX_ADDR;
_rSgRxAck = 1;
_rAck = 1;
_rState = `S_RXPORTREQ_ISSUE;
end
else if (MAIN_REQ) begin
_rLen = MAIN_LEN;
_rAddr = MAIN_ADDR;
_rMainAck = 1;
_rAck = 1;
_rState = `S_RXPORTREQ_ISSUE;
end
else begin
_rState = `S_RXPORTREQ_RX_TX;
end
end
`S_RXPORTREQ_ISSUE: begin // Issue the request
_rAck = 0;
if (rRxReqAck) begin
_rSgRxAck = 0;
_rSgTxAck = 0;
_rMainAck = 0;
if (rSgRxAck)
_rState = `S_RXPORTREQ_TX_RX;
else
_rState = `S_RXPORTREQ_RX_TX;
end
end
default: begin
_rState = `S_RXPORTREQ_RX_TX;
end
endcase
end
endmodule