| #!/usr/bin/env python |
| """ |
| Generates a Wishbone arbiter with the specified number of ports |
| """ |
| |
| from __future__ import print_function |
| |
| import argparse |
| import math |
| from jinja2 import Template |
| |
| def main(): |
| parser = argparse.ArgumentParser(description=__doc__.strip()) |
| parser.add_argument('-p', '--ports', type=int, default=2, help="number of ports") |
| parser.add_argument('-n', '--name', type=str, help="module name") |
| parser.add_argument('-o', '--output', type=str, help="output file name") |
| |
| args = parser.parse_args() |
| |
| try: |
| generate(**args.__dict__) |
| except IOError as ex: |
| print(ex) |
| exit(1) |
| |
| def generate(ports=2, name=None, output=None): |
| if name is None: |
| name = "wb_arbiter_{0}".format(ports) |
| |
| if output is None: |
| output = name + ".v" |
| |
| print("Opening file '{0}'...".format(output)) |
| |
| output_file = open(output, 'w') |
| |
| print("Generating {0} port Wishbone arbiter {1}...".format(ports, name)) |
| |
| select_width = int(math.ceil(math.log(ports, 2))) |
| |
| t = Template(u"""/* |
| |
| Copyright (c) 2015-2016 Alex Forencich |
| |
| Permission is hereby granted, free of charge, to any person obtaining a copy |
| of this software and associated documentation files (the "Software"), to deal |
| in the Software without restriction, including without limitation the rights |
| to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| copies of the Software, and to permit persons to whom the Software is |
| furnished to do so, subject to the following conditions: |
| |
| The above copyright notice and this permission notice shall be included in |
| all copies or substantial portions of the Software. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| THE SOFTWARE. |
| |
| */ |
| |
| // Language: Verilog 2001 |
| |
| `timescale 1 ns / 1 ps |
| |
| /* |
| * Wishbone {{n}} port arbiter |
| */ |
| module {{name}} # |
| ( |
| parameter DATA_WIDTH = 32, // width of data bus in bits (8, 16, 32, or 64) |
| parameter ADDR_WIDTH = 32, // width of address bus in bits |
| parameter SELECT_WIDTH = (DATA_WIDTH/8), // width of word select bus (1, 2, 4, or 8) |
| parameter ARB_TYPE = "PRIORITY", // arbitration type: "PRIORITY" or "ROUND_ROBIN" |
| parameter LSB_PRIORITY = "HIGH" // LSB priority: "LOW", "HIGH" |
| ) |
| ( |
| input wire clk, |
| input wire rst, |
| {%- for p in ports %} |
| |
| /* |
| * Wishbone master {{p}} input |
| */ |
| input wire [ADDR_WIDTH-1:0] wbm{{p}}_adr_i, // ADR_I() address input |
| input wire [DATA_WIDTH-1:0] wbm{{p}}_dat_i, // DAT_I() data in |
| output wire [DATA_WIDTH-1:0] wbm{{p}}_dat_o, // DAT_O() data out |
| input wire wbm{{p}}_we_i, // WE_I write enable input |
| input wire [SELECT_WIDTH-1:0] wbm{{p}}_sel_i, // SEL_I() select input |
| input wire wbm{{p}}_stb_i, // STB_I strobe input |
| output wire wbm{{p}}_ack_o, // ACK_O acknowledge output |
| output wire wbm{{p}}_err_o, // ERR_O error output |
| output wire wbm{{p}}_rty_o, // RTY_O retry output |
| input wire wbm{{p}}_cyc_i, // CYC_I cycle input |
| {%- endfor %} |
| |
| /* |
| * Wishbone slave output |
| */ |
| output wire [ADDR_WIDTH-1:0] wbs_adr_o, // ADR_O() address output |
| input wire [DATA_WIDTH-1:0] wbs_dat_i, // DAT_I() data in |
| output wire [DATA_WIDTH-1:0] wbs_dat_o, // DAT_O() data out |
| output wire wbs_we_o, // WE_O write enable output |
| output wire [SELECT_WIDTH-1:0] wbs_sel_o, // SEL_O() select output |
| output wire wbs_stb_o, // STB_O strobe output |
| input wire wbs_ack_i, // ACK_I acknowledge input |
| input wire wbs_err_i, // ERR_I error input |
| input wire wbs_rty_i, // RTY_I retry input |
| output wire wbs_cyc_o // CYC_O cycle output |
| ); |
| |
| wire [{{n-1}}:0] request; |
| wire [{{n-1}}:0] grant; |
| {% for p in ports %} |
| assign request[{{p}}] = wbm{{p}}_cyc_i; |
| {%- endfor %} |
| {% for p in ports %} |
| wire wbm{{p}}_sel = grant[{{p}}] & grant_valid; |
| {%- endfor %} |
| {%- for p in ports %} |
| |
| // master {{p}} |
| assign wbm{{p}}_dat_o = wbs_dat_i; |
| assign wbm{{p}}_ack_o = wbs_ack_i & wbm{{p}}_sel; |
| assign wbm{{p}}_err_o = wbs_err_i & wbm{{p}}_sel; |
| assign wbm{{p}}_rty_o = wbs_rty_i & wbm{{p}}_sel; |
| {%- endfor %} |
| |
| // slave |
| assign wbs_adr_o = {% for p in ports %}wbm{{p}}_sel ? wbm{{p}}_adr_i : |
| {% endfor %}{ADDR_WIDTH{1'b0}}; |
| |
| assign wbs_dat_o = {% for p in ports %}wbm{{p}}_sel ? wbm{{p}}_dat_i : |
| {% endfor %}{DATA_WIDTH{1'b0}}; |
| |
| assign wbs_we_o = {% for p in ports %}wbm{{p}}_sel ? wbm{{p}}_we_i : |
| {% endfor %}1'b0; |
| |
| assign wbs_sel_o = {% for p in ports %}wbm{{p}}_sel ? wbm{{p}}_sel_i : |
| {% endfor %}{SELECT_WIDTH{1'b0}}; |
| |
| assign wbs_stb_o = {% for p in ports %}wbm{{p}}_sel ? wbm{{p}}_stb_i : |
| {% endfor %}1'b0; |
| |
| assign wbs_cyc_o = {% for p in ports %}wbm{{p}}_sel ? 1'b1 : |
| {% endfor %}1'b0; |
| |
| // arbiter instance |
| arbiter #( |
| .PORTS({{n}}), |
| .TYPE(ARB_TYPE), |
| .BLOCK("REQUEST"), |
| .LSB_PRIORITY(LSB_PRIORITY) |
| ) |
| arb_inst ( |
| .clk(clk), |
| .rst(rst), |
| .request(request), |
| .acknowledge(), |
| .grant(grant), |
| .grant_valid(grant_valid), |
| .grant_encoded() |
| ); |
| |
| endmodule |
| |
| """) |
| |
| output_file.write(t.render( |
| n=ports, |
| w=select_width, |
| name=name, |
| ports=range(ports) |
| )) |
| |
| print("Done") |
| |
| if __name__ == "__main__": |
| main() |
| |