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//
// Copyright 2011 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 gpmc
#(parameter TXFIFOSIZE = 11,
parameter RXFIFOSIZE = 11,
parameter ADDR_WIDTH = 10,
parameter BUSDEBUG = 1)
(// GPMC signals
input arst,
input EM_CLK, inout [15:0] EM_D, input [ADDR_WIDTH:1] EM_A, input [1:0] EM_NBE,
input EM_WAIT0, input EM_NCS4, input EM_NCS6, input EM_NWE, input EM_NOE,
// GPIOs for FIFO signalling
output rx_have_data, output tx_have_space,
// Wishbone signals
input wb_clk, input wb_rst,
output [ADDR_WIDTH:0] wb_adr_o, output [15:0] wb_dat_mosi, input [15:0] wb_dat_miso,
output [1:0] wb_sel_o, output wb_cyc_o, output wb_stb_o, output wb_we_o, input wb_ack_i,
// FIFO interface
input fifo_clk, input fifo_rst, input clear_tx, input clear_rx,
output [35:0] tx_data_o, output tx_src_rdy_o, input tx_dst_rdy_i,
input [35:0] rx_data_i, input rx_src_rdy_i, output rx_dst_rdy_o,
output tx_underrun, output rx_overrun,
input [7:0] test_rate, input [3:0] test_ctrl,
output [31:0] debug
);
wire EM_output_enable = (~EM_NOE & (~EM_NCS4 | ~EM_NCS6));
wire [15:0] EM_D_fifo;
wire [15:0] EM_D_wb;
// these registers are used for the GPMC-to-FIFO interface
reg [15:0] em_d_reg;
reg [ADDR_WIDTH:1] em_a_reg;
reg [1:0] em_nbe_reg;
reg em_wait0_reg;
reg em_ncs4_reg;
reg em_ncs6_reg;
reg em_nwe_reg;
reg em_noe_reg;
assign EM_D = ~EM_output_enable ? 16'bz : ~EM_NCS4 ? EM_D_fifo : EM_D_wb;
// CS4 is RAM_2PORT for DATA PATH (high-speed data)
// Writes go into one RAM, reads come from the other
// CS6 is for CONTROL PATH (wishbone)
// ////////////////////////////////////////////
// TX Data Path
wire [17:0] tx18_data;
wire tx18_src_rdy, tx18_dst_rdy;
wire [35:0] tx_data, txb_data;
wire tx_src_rdy, tx_dst_rdy;
wire txb_src_rdy, txb_dst_rdy;
// Register signals to prevent Sequence errors (S-errors) from occuring
always @(negedge EM_CLK or posedge arst) begin
if (arst) begin
em_d_reg <= 0;
em_a_reg <= 0;
em_nbe_reg <= 0;
em_wait0_reg <= 0;
em_ncs4_reg <= 0;
em_ncs6_reg <= 0;
em_nwe_reg <= 0;
em_noe_reg <= 0;
end
else begin
em_d_reg <= EM_D;
em_a_reg <= EM_A;
em_nbe_reg <= EM_NBE;
em_wait0_reg <= EM_WAIT0;
em_ncs4_reg <= EM_NCS4;
em_ncs6_reg <= EM_NCS6;
em_nwe_reg <= EM_NWE;
em_noe_reg <= EM_NOE;
end
end
gpmc_to_fifo #(.ADDR_WIDTH(ADDR_WIDTH)) gpmc_to_fifo
(.EM_D(em_d_reg), .EM_A(em_a_reg), .EM_CLK(EM_CLK), .EM_WE(~em_ncs4_reg & ~em_nwe_reg),
.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx), .arst(fifo_rst | clear_tx | arst),
.data_o(tx18_data), .src_rdy_o(tx18_src_rdy), .dst_rdy_i(tx18_dst_rdy),
.have_space(tx_have_space));
fifo19_to_fifo36 #(.LE(1)) f19_to_f36 // Little endian because ARM is LE
(.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx),
.f19_datain({1'b0,tx18_data}), .f19_src_rdy_i(tx18_src_rdy), .f19_dst_rdy_o(tx18_dst_rdy),
.f36_dataout(txb_data), .f36_src_rdy_o(txb_src_rdy), .f36_dst_rdy_i(txb_dst_rdy));
fifo_cascade #(.WIDTH(36), .SIZE(TXFIFOSIZE)) tx_buffering(
.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx),
.datain(txb_data), .src_rdy_i(txb_src_rdy), .dst_rdy_o(txb_dst_rdy),
.dataout(tx_data), .src_rdy_o(tx_src_rdy), .dst_rdy_i(tx_dst_rdy)
);
// ////////////////////////////////////////////
// RX Data Path
wire [17:0] rx18_data;
wire rx18_src_rdy, rx18_dst_rdy;
wire [35:0] rx_data, rxb_data;
wire rx_src_rdy, rx_dst_rdy;
wire rxb_src_rdy, rxb_dst_rdy;
wire dummy;
fifo_cascade #(.WIDTH(36), .SIZE(RXFIFOSIZE)) rx_buffering(
.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
.datain(rx_data), .src_rdy_i(rx_src_rdy), .dst_rdy_o(rx_dst_rdy),
.dataout(rxb_data), .src_rdy_o(rxb_src_rdy), .dst_rdy_i(rxb_dst_rdy)
);
fifo36_to_fifo19 #(.LE(1)) f36_to_f19 // Little endian because ARM is LE
(.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
.f36_datain(rxb_data), .f36_src_rdy_i(rxb_src_rdy), .f36_dst_rdy_o(rxb_dst_rdy),
.f19_dataout({dummy,rx18_data}), .f19_src_rdy_o(rx18_src_rdy), .f19_dst_rdy_i(rx18_dst_rdy) );
fifo_to_gpmc #(.ADDR_WIDTH(ADDR_WIDTH)) fifo_to_gpmc
(.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx), .arst(fifo_rst | clear_rx | arst),
.data_i(rx18_data), .src_rdy_i(rx18_src_rdy), .dst_rdy_o(rx18_dst_rdy),
.EM_D(EM_D_fifo), .EM_A(EM_A), .EM_CLK(EM_CLK), .EM_OE(~EM_NCS4 & ~EM_NOE),
.data_available(rx_have_data));
// ////////////////////////////////////////////
// Control path on CS6
gpmc_wb gpmc_wb
(.EM_CLK(EM_CLK), .EM_D_in(EM_D), .EM_D_out(EM_D_wb), .EM_A(EM_A), .EM_NBE(EM_NBE),
.EM_WE(~EM_NCS6 & ~EM_NWE), .EM_OE(~EM_NCS6 & ~EM_NOE),
.wb_clk(wb_clk), .wb_rst(wb_rst),
.wb_adr_o(wb_adr_o), .wb_dat_mosi(wb_dat_mosi), .wb_dat_miso(wb_dat_miso),
.wb_sel_o(wb_sel_o), .wb_cyc_o(wb_cyc_o), .wb_stb_o(wb_stb_o), .wb_we_o(wb_we_o),
.wb_ack_i(wb_ack_i) );
// ////////////////////////////////////////////
// Test support, traffic generator, loopback, etc.
// RX side muxes test data into the same stream
wire [35:0] loopbackrx_data, testrx_data;
wire [35:0] loopbacktx_data, testtx_data;
wire loopbackrx_src_rdy, loopbackrx_dst_rdy;
wire loopbacktx_src_rdy, loopbacktx_dst_rdy;
wire sel_testtx = test_ctrl[0];
fifo36_mux rx_test_mux_lvl_2
(.clk(fifo_clk), .reset(fifo_rst), .clear(clear_rx),
.data0_i(loopbackrx_data), .src0_rdy_i(loopbackrx_src_rdy), .dst0_rdy_o(loopbackrx_dst_rdy),
.data1_i(rx_data_i), .src1_rdy_i(rx_src_rdy_i), .dst1_rdy_o(rx_dst_rdy_o),
.data_o(rx_data), .src_rdy_o(rx_src_rdy), .dst_rdy_i(rx_dst_rdy));
fifo_short #(.WIDTH(36)) loopback_fifo
(.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx | clear_rx),
.datain(loopbacktx_data), .src_rdy_i(loopbacktx_src_rdy), .dst_rdy_o(loopbacktx_dst_rdy),
.dataout(loopbackrx_data), .src_rdy_o(loopbackrx_src_rdy), .dst_rdy_i(loopbackrx_dst_rdy));
// Crossbar used as a demux for switching TX stream to main DSP or to test logic
crossbar36 tx_crossbar_lvl_1
(.clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx),
.cross(sel_testtx),
.data0_i(tx_data), .src0_rdy_i(tx_src_rdy), .dst0_rdy_o(tx_dst_rdy),
.data1_i(tx_data), .src1_rdy_i(1'b0), .dst1_rdy_o(), // No 2nd input
.data0_o(tx_data_o), .src0_rdy_o(tx_src_rdy_o), .dst0_rdy_i(tx_dst_rdy_i),
.data1_o(loopbacktx_data), .src1_rdy_o(loopbacktx_src_rdy), .dst1_rdy_i(loopbacktx_dst_rdy) );
assign debug = {
EM_D, //16
EM_A, //10
EM_CLK, EM_NCS4, EM_NWE, EM_NOE, //4
EM_NCS6, wb_ack_i
};
endmodule // gpmc
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