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riffa/fpga/riffa_hdl/tx_data_shift.v

327 lines
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Verilog

// ----------------------------------------------------------------------
// Copyright (c) 2015, 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: tx_data_shift.v
// Version: 1.0
// Verilog Standard: Verilog-2001
//
// Description: The TX Data Shift module takes arbitrarily 32-bit aligned data
// from the WR_TX_DATA interface and shifts the data so that it is 0-bit aligned
// on the output RD_TX_DATA interface. The VALID, END_OFFSET, and END_FLAG signal
// in the WR_TX_DATA interface are replaced by WORD_VALID and END_FLAGS signals in
// the RD_TX_DATA interface. Each bit in the WORD_VALID bus indicates that the
// corresponding dword in the RD_TX_DATA bus is valid. Each bit in the END_FLAGS
// bus indicates that the end of the payload occurs at the corresponding dword in
// the RD_TX_DATA bus.
//
// The core of the TX_DATA_SHIFT module is a set of N multiplexers, where N =
// (C_DATA_WIDTH/32). The multiplexers are surrounded by a set of optional
// input and output registers with output wires wWrTxData* and input wires
// wRdTxData*. Each register in the array rMuxSelect choses which mux input
// desplay on the mux output. The values of the registers are set based on the
// value of wWrTxDataStartOffset. These registers are enabled when
// wWrTxDataStartFlag is 1 and their value set based on the value of
// wWrTxDataStartOffset.
//
// Each bit in the VALID bus is determined by the result of two masks,
// wRdTxEndFlagMask and wRdTxStartFlagMask, to make wRdTxDataValid. The start flag
// mask is active when wWrTxDataStartFlag is 1, based on wWrTxDataStartOffset. The
// end flag mask is active when wWrTxDataEndFlag is 1, based on
// wWrTxDataEndOffset.
//
// TODO:
// - Using WORD_VALID is a little bit confusing. I should bring back VALID as well
// - WORD_VALID should be DWORD_VALID
// - Use a uniform naming scheme for C_DATA_WIDTH/32
// - Is there a more efficient way to implement the wRdTxStartMaskFlag? Perhaps using the reset of a register?
// Author: Dustin Richmond (@darichmond)
//-----------------------------------------------------------------------------
`timescale 1ns/1ns
`include "trellis.vh"
module tx_data_shift
#(
parameter C_PIPELINE_OUTPUT = 1,
parameter C_PIPELINE_INPUT = 1,
parameter C_DATA_WIDTH = 128,
parameter C_VENDOR = "ALTERA"
)
(
// Interface: Clocks
input CLK,
// Interface: Reset
input RST_IN,
// Interface: WR TX DATA
input WR_TX_DATA_VALID,
input [C_DATA_WIDTH-1:0] WR_TX_DATA,
input WR_TX_DATA_START_FLAG,
input [clog2s(C_DATA_WIDTH/32)-1:0] WR_TX_DATA_START_OFFSET,
input WR_TX_DATA_END_FLAG,
input [clog2s(C_DATA_WIDTH/32)-1:0] WR_TX_DATA_END_OFFSET,
output WR_TX_DATA_READY,
// Interface: RD TX DATA
input RD_TX_DATA_READY,
output [C_DATA_WIDTH-1:0] RD_TX_DATA,
output RD_TX_DATA_START_FLAG,
output [(C_DATA_WIDTH/32)-1:0] RD_TX_DATA_WORD_VALID,
output [(C_DATA_WIDTH/32)-1:0] RD_TX_DATA_END_FLAGS,
output RD_TX_DATA_VALID
);
localparam C_ROTATE_BITS = clog2s(C_DATA_WIDTH/32);
localparam C_NUM_MUXES = (C_DATA_WIDTH/32);
localparam C_SELECT_WIDTH = C_DATA_WIDTH/32;
localparam C_MASK_WIDTH = C_DATA_WIDTH/32;
localparam C_AGGREGATE_WIDTH = C_DATA_WIDTH;
genvar i;
wire wWrTxDataValid;
wire [C_DATA_WIDTH-1:0] wWrTxData;
wire wWrTxDataStartFlag;
wire [clog2s(C_DATA_WIDTH/32)-1:0] wWrTxDataStartOffset;
wire wWrTxDataEndFlag;
wire [clog2s(C_DATA_WIDTH/32)-1:0] wWrTxDataEndOffset;
wire [(C_DATA_WIDTH/32)-1:0] wWrTxEndFlagMask;
wire [(C_DATA_WIDTH/32)-1:0] wWrTxDataEndFlags;
wire wWrTxDataReady;
wire wRdTxDataReady;
wire [C_DATA_WIDTH-1:0] wRdTxData;
wire wRdTxDataStartFlag;
wire [(C_DATA_WIDTH/32)-1:0] wRdTxDataEndFlags;
wire [(C_DATA_WIDTH/32)-1:0] wRdTxDataWordValid;
wire [(C_DATA_WIDTH/32)-1:0] wRdTxStartFlagMask;
wire [(C_DATA_WIDTH/32)-1:0] wRdTxEndFlagMask;
wire wRdTxDataValid;
// wSelectDefault is the default select value for each mux, 1 << i where i
// is the mux/dword index.
wire [C_SELECT_WIDTH-1:0] wSelectDefault[C_NUM_MUXES-1:0];
// wSelectRotated is the value the select for each mux after the data's
// start offset has been applied and until the end flag is seen.
wire [C_SELECT_WIDTH-1:0] wSelectRotated[C_NUM_MUXES-1:0];
reg [C_SELECT_WIDTH-1:0] rMuxSelect[C_NUM_MUXES-1:0],_rMuxSelect[C_NUM_MUXES-1:0];
reg [clog2s(C_DATA_WIDTH/32)-1:0] rStartOffset,_rStartOffset;
assign wWrTxDataReady = wRdTxDataReady;
assign wRdTxStartFlagMask = wWrTxDataStartFlag ?
{(C_DATA_WIDTH/32){1'b1}} >> wWrTxDataStartOffset:
{(C_DATA_WIDTH/32){1'b1}};
assign wRdTxDataWordValid = wRdTxEndFlagMask & wRdTxStartFlagMask;
assign wRdTxDataStartFlag = wWrTxDataStartFlag;
assign wRdTxDataValid = wWrTxDataValid;
generate
for (i = 0; i < C_NUM_MUXES; i = i + 1) begin : gen_mux_default
assign wSelectDefault[i] = (1 << i);
end
endgenerate
always @(*) begin
_rStartOffset = WR_TX_DATA_START_OFFSET;
end
always @(posedge CLK) begin
if(WR_TX_DATA_READY & WR_TX_DATA_START_FLAG & WR_TX_DATA_VALID) begin
rStartOffset <= _rStartOffset;
end
end
generate
for (i = 0; i < C_NUM_MUXES; i = i + 1) begin : gen_mux_select
always @(*) begin
_rMuxSelect[i] = wSelectRotated[i];
end
always @(posedge CLK) begin
if(WR_TX_DATA_READY & WR_TX_DATA_START_FLAG) begin
rMuxSelect[i] <= _rMuxSelect[i];
end
end
end
endgenerate
pipeline
#(// Parameters
.C_WIDTH (C_DATA_WIDTH+2*(1+clog2s(C_DATA_WIDTH/32))),
.C_USE_MEMORY (0),
.C_DEPTH (C_PIPELINE_INPUT?1:0)
/*AUTOINSTPARAM*/)
input_register
(
// Outputs
.WR_DATA_READY (WR_TX_DATA_READY),
.RD_DATA ({wWrTxData,wWrTxDataStartFlag,wWrTxDataStartOffset,wWrTxDataEndFlag,wWrTxDataEndOffset}),
.RD_DATA_VALID (wWrTxDataValid),
// Inputs
.WR_DATA ({WR_TX_DATA,WR_TX_DATA_START_FLAG,WR_TX_DATA_START_OFFSET,
WR_TX_DATA_END_FLAG,WR_TX_DATA_END_OFFSET}),
.WR_DATA_VALID (WR_TX_DATA_VALID),
.RD_DATA_READY (wWrTxDataReady),
/*AUTOINST*/
// Inputs
.CLK (CLK),
.RST_IN (RST_IN));
// The pipeline carries the data bus and SOF/EOF.
pipeline
#(// Parameters
.C_WIDTH (C_DATA_WIDTH + 2*C_MASK_WIDTH + 1),
.C_USE_MEMORY (0),
.C_DEPTH ((C_PIPELINE_OUTPUT > 1) ? 1 : 0)
/*AUTOINSTPARAM*/)
output_register
(
// Outputs
.WR_DATA_READY (wRdTxDataReady),
.RD_DATA ({RD_TX_DATA,RD_TX_DATA_START_FLAG,
RD_TX_DATA_END_FLAGS,RD_TX_DATA_WORD_VALID}),
.RD_DATA_VALID (RD_TX_DATA_VALID),
// Inputs
.WR_DATA ({wRdTxData,wRdTxDataStartFlag,
wRdTxDataEndFlags,wRdTxDataWordValid}),
.WR_DATA_VALID (wRdTxDataValid),
.RD_DATA_READY (RD_TX_DATA_READY),
/*AUTOINST*/
// Inputs
.CLK (CLK),
.RST_IN (RST_IN));
offset_to_mask
#(
.C_MASK_SWAP (0),
/*AUTOINSTPARAM*/
// Parameters
.C_MASK_WIDTH (C_MASK_WIDTH))
eof_convert
(
// Outputs
.MASK (wWrTxEndFlagMask),
// Inputs
.OFFSET_ENABLE (wWrTxDataEndFlag),
.OFFSET (wWrTxDataEndOffset)
/*AUTOINST*/);
rotate
#(
// Parameters
.C_DIRECTION ("RIGHT"),
.C_WIDTH (C_DATA_WIDTH/32)
/*AUTOINSTPARAM*/)
em_rotate_inst
(
// Outputs
.RD_DATA (wRdTxEndFlagMask),
// Inputs
.WR_DATA (wWrTxEndFlagMask),
.WR_SHIFTAMT (rStartOffset[clog2s(C_DATA_WIDTH/32)-1:0])
/*AUTOINST*/);
// Determine the 1-hot dword end flag
offset_flag_to_one_hot
#(
.C_WIDTH (C_DATA_WIDTH/32)
/*AUTOINSTPARAM*/)
ef_onehot_inst
(
// Outputs
.RD_ONE_HOT (wWrTxDataEndFlags),
// Inputs
.WR_OFFSET (wWrTxDataEndOffset[clog2s(C_DATA_WIDTH/32)-1:0]),
.WR_FLAG (wWrTxDataEndFlag)
/*AUTOINST*/);
rotate
#(
// Parameters
.C_DIRECTION ("RIGHT"),
.C_WIDTH (C_DATA_WIDTH/32)
/*AUTOINSTPARAM*/)
ef_rotate_inst
(
// Outputs
.RD_DATA (wRdTxDataEndFlags),
// Inputs
.WR_DATA (wWrTxDataEndFlags),
.WR_SHIFTAMT (rStartOffset[clog2s(C_DATA_WIDTH/32)-1:0])
/*AUTOINST*/);
generate
for (i = 0; i < C_NUM_MUXES; i = i + 1) begin : gen_rotates
rotate
#(
// Parameters
.C_DIRECTION ("LEFT"),
.C_WIDTH ((C_DATA_WIDTH/32))
/*AUTOINSTPARAM*/)
select_rotate_inst_
(
// Outputs
.RD_DATA (wSelectRotated[i]),
// Inputs
.WR_DATA (wSelectDefault[i]),
.WR_SHIFTAMT (WR_TX_DATA_START_OFFSET[C_ROTATE_BITS-1:0])
/*AUTOINST*/);
end
endgenerate
generate
for (i = 0; i < C_DATA_WIDTH/32; i = i + 1) begin : gen_multiplexers
one_hot_mux
#(
.C_DATA_WIDTH (32),
/*AUTOINSTPARAM*/
// Parameters
.C_SELECT_WIDTH (C_SELECT_WIDTH),
.C_AGGREGATE_WIDTH (C_AGGREGATE_WIDTH))
mux_inst_
(
// Inputs
.ONE_HOT_SELECT (rMuxSelect[i]),
// Outputs
.ONE_HOT_OUTPUT (wRdTxData[32*i +: 32]),
.ONE_HOT_INPUTS (wWrTxData)
/*AUTOINST*/);
end
endgenerate
endmodule
// Local Variables:
// verilog-library-directories:("." "../../../common/" "../../common/")
// End: