// SPDX-FileCopyrightText: 
// 2021 Andrew Attwood
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0


`timescale 1 ps / 1 ps

module inter #(
        parameter DATA_WIDTH = 32,
        parameter MASTER_ADDR_WIDTH = 12,
        parameter SLAVE_ADDR_WIDTH = 10,
        parameter MASTERS = 4,
        parameter SLAVES = 2
)(
        clk,
        reset,
        master_data_req_i,
        master_data_addr_i,
        master_data_we_i,
        master_data_be_i,
        master_data_wdata_i,
        master_data_rdata_o,
        master_data_rvalid_o,
        master_data_gnt_o,
        slave_data_req_o,
        slave_data_addr_o,
        slave_data_we_o,
        slave_data_be_o,
        slave_data_wdata_o,
        slave_data_rdata_i,
        slave_data_rvalid_i,
        slave_data_gnt_i
);

        input clk;
        input reset;
        input wire [MASTERS - 1:0] master_data_req_i;
        input wire [(MASTERS * MASTER_ADDR_WIDTH) - 1:0] master_data_addr_i;
        input wire [MASTERS - 1:0] master_data_we_i;
        input wire [(MASTERS * (DATA_WIDTH / 8)) - 1:0] master_data_be_i;
        input wire [(MASTERS * DATA_WIDTH) - 1:0] master_data_wdata_i;
        output reg [(MASTERS * DATA_WIDTH) - 1:0] master_data_rdata_o;
        output reg [MASTERS - 1:0] master_data_rvalid_o;
        output reg [MASTERS - 1:0] master_data_gnt_o;
        output reg [SLAVES - 1:0] slave_data_req_o;
        output reg [(SLAVES * SLAVE_ADDR_WIDTH) - 1:0] slave_data_addr_o;
        output reg [SLAVES - 1:0] slave_data_we_o;
        output reg [(SLAVES * (DATA_WIDTH / 8)) - 1:0] slave_data_be_o;
        output reg [(SLAVES * DATA_WIDTH) - 1:0] slave_data_wdata_o;
        input wire [(SLAVES * DATA_WIDTH) - 1:0] slave_data_rdata_i;
        input wire [SLAVES - 1:0] slave_data_rvalid_i;
        input wire [SLAVES - 1:0] slave_data_gnt_i;
        reg arb_to_master_grant [MASTERS - 1:0];
        wire arb_active;
        genvar i;
        //genvar j;
        logic [(SLAVES * MASTERS) - 1:0] arbiter_request;
        wire [(SLAVES * MASTERS) - 1:0] arbiter_grant;
       //parameter [$clog2(SLAVES):0] PARAM_SLAVE_ADDR = 2'b10;
        
                for (i = 0; i < SLAVES; i = i + 1)  
                always @(*)
                begin
                        integer j;
                        for (j = 0; j < MASTERS; j = j + 1) begin
                                arbiter_request[(i * MASTERS) + j] = (  master_data_addr_i[(j * MASTER_ADDR_WIDTH + (SLAVE_ADDR_WIDTH )) +: $clog2(SLAVES)]   == i )? master_data_req_i[j] : 0;
                        end
                end
                for (i = 0; i < MASTERS; i = i + 1)
                        begin : sv2v_autoblock_1
                           always @(*)begin
                                reg local_arb_grant;
                                local_arb_grant = 1'b0;
                                begin : sv2v_autoblock_2
                                        reg signed [31:0] j;
                                        for (j = 0; j < SLAVES; j = j + 1)
                                                local_arb_grant = local_arb_grant | arbiter_grant[(j * MASTERS) + i];
                                end
                                arb_to_master_grant[i] = local_arb_grant;
                           end
                        end

                        
        generate
                for (i = 0; i < SLAVES; i = i + 1) begin : generate_arbiters
                        arbiter #(.NUM_PORTS(MASTERS)) i_arb(
                                .clk(clk),
                                .rst(reset),
                                .request(arbiter_request[(i * MASTERS) + (MASTERS - 1)-:MASTERS]),
                                .grant(arbiter_grant[(i * MASTERS) + (MASTERS - 1)-:MASTERS]),
                                .active(arb_active)
                        );
                end
        endgenerate
        genvar a,t;
         
         generate
                 for ( a = 0; a < SLAVES; a = a + 1)
                        begin : slave_out1
                          
                                always @(*)
                                begin 
                                        
                                        slave_data_addr_o[a * SLAVE_ADDR_WIDTH+:SLAVE_ADDR_WIDTH] = 0;
                                        slave_data_we_o[a] = 0;
                                        slave_data_be_o[a * (DATA_WIDTH / 8)+:DATA_WIDTH / 8] = 0;
                                        slave_data_wdata_o[a * DATA_WIDTH+:DATA_WIDTH] = 0;
                                        slave_data_req_o[a] = 0;
                                        integer t;
                                        for ( t = 0; t < MASTERS; t = t + 1)
                                        begin : slave_out2
                                                
                                
                                                if (arbiter_grant[(a*MASTERS) + t] == 1'b1) begin : slave_out
                                                        slave_data_addr_o[a * SLAVE_ADDR_WIDTH+:SLAVE_ADDR_WIDTH] = master_data_addr_i[t * MASTER_ADDR_WIDTH+:MASTER_ADDR_WIDTH];
                                                        slave_data_we_o[a] = master_data_we_i[t];
                                                        slave_data_be_o[a * (DATA_WIDTH / 8)+:DATA_WIDTH / 8] = master_data_be_i[t * (DATA_WIDTH / 8)+:DATA_WIDTH / 8];
                                                        slave_data_wdata_o[a * DATA_WIDTH+:DATA_WIDTH] = master_data_wdata_i[t * DATA_WIDTH+:DATA_WIDTH];
                                                        //need to fix
                                                        slave_data_req_o[a] = master_data_req_i[t];
                                                end
                                        end
                                end
                             

                        end
         endgenerate
        
        generate
        for (i = 0; i < MASTERS; i = i + 1)
                begin :m_data1
                        always @(*)                       
                        begin :m_data2
                                master_data_rdata_o[i * DATA_WIDTH+:DATA_WIDTH] = 0;
                                master_data_rvalid_o[i] = 0;
                                master_data_gnt_o[i] = 0;
                                integer k;
                                for (k = 0; k < SLAVES; k = k + 1)
                                begin
                                        if (arbiter_grant[(k * MASTERS) + i] == 1'b1) 
                                        begin 
                                                master_data_rdata_o[i * DATA_WIDTH+:DATA_WIDTH] = slave_data_rdata_i[k * DATA_WIDTH+:DATA_WIDTH];
                                                master_data_rvalid_o[i] = slave_data_rvalid_i[k];
                                                master_data_gnt_o[i] = slave_data_gnt_i[k] & master_data_req_i[i] ;
                                        end
                                end
                        end
                end
        endgenerate
endmodule


/**
The MIT License (MIT)

Copyright (c) 2013 Berin Martini

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.

 * Module: arbiter
 *
 * Description:
 *  A look ahead, round-robing parameterized arbiter.
 *
 * <> request
 *  each bit is controlled by an actor and each actor can 'request' ownership
 *  of the shared resource by bring high its request bit.
 *
 * <> grant
 *  when an actor has been given ownership of shared resource its 'grant' bit
 *  is driven high
 *
 * <> select
 *  binary representation of the grant signal (optional use)
 *
 * <> active
 *  is brought high by the arbiter when (any) actor has been given ownership
 *  of shared resource.
 *
 *
 * Created: Sat Jun  1 20:26:44 EDT 2013
 *
 * Author:  Berin Martini // berin.martini@gmail.com
 */

module arbiter     #(
    parameter NUM_PORTS=5
    )(
	clk,
	rst,
	request,
	grant,
	select,
	active
);
	parameter SEL_WIDTH = (NUM_PORTS > 1 ? $clog2(NUM_PORTS) : 1);
	input clk;
	input rst;
	input [NUM_PORTS - 1:0] request;
	output reg [NUM_PORTS - 1:0] grant;
	output reg [SEL_WIDTH - 1:0] select;
	output reg active;
	localparam WRAP_LENGTH = 2 * NUM_PORTS;
	function [SEL_WIDTH - 1:0] ff1;
		input [NUM_PORTS - 1:0] in;
		reg set;
		integer i;
		begin
			set = 1'b0;
			ff1 = 'b0;
			for (i = 0; i < NUM_PORTS; i = i + 1)
				if (in[i] & ~set) begin
					set = 1'b1;
					ff1 = i[0+:SEL_WIDTH];
				end
		end
	endfunction
	integer yy;
	wire next;
	wire [NUM_PORTS - 1:0] order;
	reg [NUM_PORTS - 1:0] token;
	wire [NUM_PORTS - 1:0] token_lookahead [NUM_PORTS - 1:0];
	wire [WRAP_LENGTH - 1:0] token_wrap;
	assign token_wrap = {token, token};
	assign next = ~|(token & request);
	always @(posedge clk) grant <= token & request;
	always @(posedge clk) select <= ff1(token & request);
	always @(posedge clk) active <= |(token & request);
	always @(posedge clk)
		if (rst)
			token <= 'b1;
		else if (next)
			for (yy = 0; yy < NUM_PORTS; yy = yy + 1)
				begin : TOKEN_
					if (order[yy])
						token <= token_lookahead[yy];
				end
	genvar xx;
	generate
		for (xx = 0; xx < NUM_PORTS; xx = xx + 1) begin : ORDER_
			assign token_lookahead[xx] = token_wrap[xx+:NUM_PORTS];
			assign order[xx] = |(token_lookahead[xx] & request);
		end
	endgenerate
endmodule