| 1 | // ========== Copyright Header Begin ========================================== |
| 2 | // |
| 3 | // OpenSPARC T2 Processor File: niu_pio_accepted_sm.v |
| 4 | // Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved |
| 5 | // 4150 Network Circle, Santa Clara, California 95054, U.S.A. |
| 6 | // |
| 7 | // * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 8 | // |
| 9 | // This program is free software; you can redistribute it and/or modify |
| 10 | // it under the terms of the GNU General Public License as published by |
| 11 | // the Free Software Foundation; version 2 of the License. |
| 12 | // |
| 13 | // This program is distributed in the hope that it will be useful, |
| 14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | // GNU General Public License for more details. |
| 17 | // |
| 18 | // You should have received a copy of the GNU General Public License |
| 19 | // along with this program; if not, write to the Free Software |
| 20 | // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 21 | // |
| 22 | // For the avoidance of doubt, and except that if any non-GPL license |
| 23 | // choice is available it will apply instead, Sun elects to use only |
| 24 | // the General Public License version 2 (GPLv2) at this time for any |
| 25 | // software where a choice of GPL license versions is made |
| 26 | // available with the language indicating that GPLv2 or any later version |
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| 34 | // ========== Copyright Header End ============================================ |
| 35 | /*%W% %G%*/ |
| 36 | |
| 37 | /************************************************************************* |
| 38 | * |
| 39 | * File Name : niu_pio_accepted_sm.v |
| 40 | * Author Name : John Lo |
| 41 | * Description : It contains niu pio interface, interrupt controller, |
| 42 | * UCB for N2. |
| 43 | * Parent Module: niu |
| 44 | * Child Module: |
| 45 | * Interface Mod: many. |
| 46 | * Date Created : 3/08/2004 |
| 47 | * |
| 48 | * Copyright (c) 2020, Sun Microsystems, Inc. |
| 49 | * Sun Proprietary and Confidential |
| 50 | * |
| 51 | * Modification : |
| 52 | * |
| 53 | * Synthesis Notes: |
| 54 | * |
| 55 | *************************************************************************/ |
| 56 | |
| 57 | module niu_pio_accepted_sm (/*AUTOARG*/ |
| 58 | // Outputs |
| 59 | accepted, accepted_state, |
| 60 | // Inputs |
| 61 | clk, reset, full, ucb_rd_req, ucb_wr_req |
| 62 | ); |
| 63 | |
| 64 | input clk; |
| 65 | input reset; |
| 66 | input full; |
| 67 | input ucb_rd_req; |
| 68 | input ucb_wr_req; |
| 69 | |
| 70 | output accepted; |
| 71 | output [1:0] accepted_state; |
| 72 | |
| 73 | reg [1:0] nx_accepted_state; |
| 74 | reg accepted; |
| 75 | |
| 76 | parameter IDLE = 2'd0; |
| 77 | parameter ACCEPT = 2'd1; |
| 78 | parameter DLY1 = 2'd2; |
| 79 | parameter DLY2 = 2'd3; |
| 80 | |
| 81 | // combination logic |
| 82 | always @ (/*AUTOSENSE*/accepted_state or full or ucb_rd_req |
| 83 | or ucb_wr_req) |
| 84 | begin |
| 85 | nx_accepted_state = IDLE; |
| 86 | accepted = 0; |
| 87 | case (accepted_state) // synopsys full_case parallel_case |
| 88 | IDLE: begin |
| 89 | if ((~full) & (ucb_rd_req | ucb_wr_req)) |
| 90 | nx_accepted_state = ACCEPT; |
| 91 | else nx_accepted_state = accepted_state; // stay |
| 92 | end |
| 93 | |
| 94 | ACCEPT: begin |
| 95 | nx_accepted_state = DLY1; |
| 96 | accepted = 1; |
| 97 | |
| 98 | end |
| 99 | DLY1: nx_accepted_state = DLY2; |
| 100 | |
| 101 | DLY2: nx_accepted_state = IDLE; |
| 102 | |
| 103 | default:begin |
| 104 | nx_accepted_state = IDLE; |
| 105 | accepted = 0; |
| 106 | end |
| 107 | endcase |
| 108 | end |
| 109 | |
| 110 | // seq part |
| 111 | dffr #(2) accepted_state_dffr(.d(nx_accepted_state[1:0]),.reset(reset),.clk(clk),.q(accepted_state[1:0])); |
| 112 | |
| 113 | |
| 114 | endmodule // niu_pio_accepted_sm |
| 115 | |
| 116 | |