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//
// Copyright 2012 Ettus Research LLC
//
`define LOG2(N) (\
N < 2 ? 0 : \
N < 4 ? 1 : \
N < 8 ? 2 : \
N < 16 ? 3 : \
N < 32 ? 4 : \
N < 64 ? 5 : \
N < 128 ? 6 : \
N < 256 ? 7 : \
N < 512 ? 8 : \
N < 1024 ? 9 : \
10)
module axi_crossbar
#(
parameter FIFO_WIDTH = 64, // AXI4-STREAM data bus width
parameter DST_WIDTH = 16, // Width of DST field we are routing on.
parameter NUM_INPUTS = 2, // number of input AXI4-STREAM buses
parameter NUM_OUTPUTS = 2 // number of output AXI4-STREAM buses
)
(
input clk,
input reset,
input clear,
input [7:0] local_addr,
// Inputs
input [(FIFO_WIDTH*NUM_INPUTS)-1:0] i_tdata,
input [NUM_INPUTS-1:0] i_tvalid,
input [NUM_INPUTS-1:0] i_tlast,
output [NUM_INPUTS-1:0] i_tready,
input [NUM_INPUTS-1:0] pkt_present,
// Setting Bus
input set_stb,
input [15:0] set_addr,
input [31:0] set_data,
// Output
output [(FIFO_WIDTH*NUM_OUTPUTS)-1:0] o_tdata,
output [NUM_OUTPUTS-1:0] o_tvalid,
output [NUM_OUTPUTS-1:0] o_tlast,
input [NUM_OUTPUTS-1:0] o_tready,
// readback bus
input rb_rd_stb,
input [`LOG2(NUM_OUTPUTS)+`LOG2(NUM_INPUTS)-1:0] rb_addr,
output [31:0] rb_data
);
genvar m,n;
wire [(NUM_INPUTS*NUM_OUTPUTS)-1:0] forward_valid_in;
wire [(NUM_INPUTS*NUM_OUTPUTS)-1:0] forward_ack_in;
wire [(NUM_INPUTS*NUM_OUTPUTS)-1:0] forward_valid_out;
wire [(NUM_INPUTS*NUM_OUTPUTS)-1:0] forward_ack_out;
wire [NUM_INPUTS-1:0] i_tready_slave [0:NUM_OUTPUTS-1];
//
// Instantiate an axi_slave_mux for every slave/output of the Crossbar switch.
// Each axi_slave_mux contains logic to maux and resolve arbitration
// for this particular slave/output.
//
generate
for (m = 0; m < NUM_OUTPUTS; m = m + 1) begin: instantiate_slave_mux
wire [NUM_INPUTS-1:0] i_tready_tmp;
axi_slave_mux
#(
.FIFO_WIDTH(FIFO_WIDTH), // AXI4-STREAM data bus width
.DST_WIDTH(DST_WIDTH), // Width of DST field we are routing on.
.NUM_INPUTS(NUM_INPUTS) // number of input AXI buses
) axi_slave_mux_i
(
.clk(clk),
.reset(reset),
.clear(clear),
// Inputs
.i_tdata(i_tdata),
.i_tvalid(i_tvalid),
.i_tlast(i_tlast),
.i_tready(i_tready_tmp),
// Forwarding flags (One from each Input/Master)
.forward_valid(forward_valid_in[(m+1)*NUM_INPUTS-1:m*NUM_INPUTS]),
.forward_ack(forward_ack_out[(m+1)*NUM_INPUTS-1:m*NUM_INPUTS]),
// Output
.o_tdata(o_tdata[(m*FIFO_WIDTH)+FIFO_WIDTH-1:m*FIFO_WIDTH]),
.o_tvalid(o_tvalid[m]),
.o_tlast(o_tlast[m]),
.o_tready(o_tready[m])
);
if (m==0)
assign i_tready_slave[0] = i_tready_tmp;
else
assign i_tready_slave[m] = i_tready_tmp | i_tready_slave[m-1] ;
end // block: instantiate_slave_mux
endgenerate
assign i_tready = i_tready_slave[NUM_OUTPUTS-1];
//
// Permute the forwarding flag buses
//
generate
for (m = 0; m < NUM_OUTPUTS; m = m + 1) begin: permute_outer
for (n = 0; n < NUM_INPUTS; n = n + 1) begin: permute_inner
assign forward_valid_in[n*NUM_OUTPUTS+m] = forward_valid_out[n+m*NUM_INPUTS];
assign forward_ack_in[n+m*NUM_INPUTS] = forward_ack_out[n*NUM_OUTPUTS+m];
end
end
endgenerate
//
// Instantiate an axi_forwarding_cam for every Input/Master of the Crossbar switch.
// Each contains a TCAM like lookup that allocates an egress port.
//
wire [31:0] rb_data_mux[0:NUM_INPUTS-1];
generate
for (m = 0; m < NUM_INPUTS; m = m + 1) begin: instantiate_cam
axi_forwarding_cam
#(
.BASE(0),
.WIDTH(FIFO_WIDTH), // Bit width of FIFO word.
.NUM_OUTPUTS(NUM_OUTPUTS)
) axi_forwarding_cam_i
(
.clk(clk),
.reset(reset),
.clear(clear),
// Monitored FIFO signals
.o_tdata(i_tdata[(m*FIFO_WIDTH)+FIFO_WIDTH-1:m*FIFO_WIDTH]),
.o_tvalid(i_tvalid[m]),
.o_tready(i_tready[m]),
.o_tlast(i_tlast[m]),
.pkt_present(pkt_present[m]),
// Configuration
.local_addr(local_addr),
// Setting Bus
.set_stb(set_stb),
.set_addr(set_addr),
.set_data(set_data),
// Header signals
.forward_valid(forward_valid_out[(m+1)*NUM_OUTPUTS-1:m*NUM_OUTPUTS]),
.forward_ack(forward_ack_in[(m+1)*NUM_OUTPUTS-1:m*NUM_OUTPUTS]),
// Readback bus
.rb_rd_stb(rb_rd_strobe && (rb_addr[`LOG2(NUM_OUTPUTS)+`LOG2(NUM_INPUTS)-1:`LOG2(NUM_OUTPUTS)] == m)),
.rb_addr(rb_addr[`LOG2(NUM_OUTPUTS)-1:0]),
.rb_data(rb_data_mux[m])
);
end // block: instantiate_fifo_header
endgenerate
assign rb_data = rb_data_mux[rb_addr[`LOG2(NUM_OUTPUTS)+`LOG2(NUM_INPUTS)-1:`LOG2(NUM_OUTPUTS)]];
endmodule // axi_crossbar
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