Subversion Repositories openrisc_2011-10-31

//////////////////////////////////////////////////////////////////////

////                                                              ////

////  OR1200's Programmable Interrupt Controller                  ////

////                                                              ////

////  This file is part of the OpenRISC 1200 project              ////

////  http://www.opencores.org/project,or1k                       ////

////                                                              ////

////  Description                                                 ////

////  PIC according to OR1K architectural specification.          ////

////                                                              ////

////  To Do:                                                      ////

////   None                                                       ////

////                                                              ////

////  Author(s):                                                  ////

////      - Damjan Lampret, lampret@opencores.org                 ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2000 Authors and OPENCORES.ORG                 ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 of the License, or (at your option) any   ////

//// later version.                                               ////

////                                                              ////

//// This source 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 Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

//

// $Log: or1200_pic.v,v $

// Revision 2.0  2010/06/30 11:00:00  ORSoC

//

// synopsys translate_off

`include "timescale.v"

// synopsys translate_on

`include "or1200_defines.v"

module or1200_pic(

        // RISC Internal Interface

        clk, rst, spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o,

        pic_wakeup, intr,

        // PIC Interface

        pic_int

);

//

// RISC Internal Interface

//

input           clk;            // Clock

input           rst;            // Reset

input           spr_cs;         // SPR CS

input           spr_write;      // SPR Write

input   [31:0]   spr_addr;       // SPR Address

input   [31:0]   spr_dat_i;      // SPR Write Data

output  [31:0]   spr_dat_o;      // SPR Read Data

output          pic_wakeup;     // Wakeup to the PM

output          intr;           // interrupt

                                // exception request

//

// PIC Interface

//

input   [`OR1200_PIC_INTS-1:0]   pic_int;// Interrupt inputs

`ifdef OR1200_PIC_IMPLEMENTED

//

// PIC Mask Register bits (or no register)

//

`ifdef OR1200_PIC_PICMR

reg     [`OR1200_PIC_INTS-1:2]  picmr;  // PICMR bits

`else

wire    [`OR1200_PIC_INTS-1:2]  picmr;  // No PICMR register

`endif

//

// PIC Status Register bits (or no register)

//

`ifdef OR1200_PIC_PICSR

reg     [`OR1200_PIC_INTS-1:0]   picsr;  // PICSR bits

`else

wire    [`OR1200_PIC_INTS-1:0]   picsr;  // No PICSR register

`endif

//

// Internal wires & regs

//

wire            picmr_sel;      // PICMR select

wire            picsr_sel;      // PICSR select

wire    [`OR1200_PIC_INTS-1:0] um_ints;// Unmasked interrupts

reg     [31:0]   spr_dat_o;      // SPR data out

//

// PIC registers address decoder

//

assign picmr_sel = (spr_cs && (spr_addr[`OR1200_PICOFS_BITS] == `OR1200_PIC_OFS_PICMR)) ? 1'b1 : 1'b0;

assign picsr_sel = (spr_cs && (spr_addr[`OR1200_PICOFS_BITS] == `OR1200_PIC_OFS_PICSR)) ? 1'b1 : 1'b0;

//

// Write to PICMR

//

`ifdef OR1200_PIC_PICMR

always @(posedge clk or `OR1200_RST_EVENT rst)

        if (rst == `OR1200_RST_VALUE)

                picmr <= {1'b1, {`OR1200_PIC_INTS-3{1'b0}}};

        else if (picmr_sel && spr_write) begin

                picmr <=  spr_dat_i[`OR1200_PIC_INTS-1:2];

        end

`else

assign picmr = (`OR1200_PIC_INTS)'b1;

`endif

//

// Write to PICSR, both CPU and external ints

//

`ifdef OR1200_PIC_PICSR

always @(posedge clk or `OR1200_RST_EVENT rst)

        if (rst == `OR1200_RST_VALUE)

                picsr <= {`OR1200_PIC_INTS{1'b0}};

        else if (picsr_sel && spr_write) begin

                picsr <=  spr_dat_i[`OR1200_PIC_INTS-1:0] | um_ints;

        end else

                picsr <=  picsr | um_ints;

`else

assign picsr = pic_int;

`endif

//

// Read PIC registers

//

always @(spr_addr or picmr or picsr)

        case (spr_addr[`OR1200_PICOFS_BITS])    // synopsys parallel_case

`ifdef OR1200_PIC_READREGS

                `OR1200_PIC_OFS_PICMR: begin

                   spr_dat_o[`OR1200_PIC_INTS-1:0] = {picmr, 2'b11};

 `ifdef OR1200_PIC_UNUSED_ZERO

                   spr_dat_o[31:`OR1200_PIC_INTS] = {32-`OR1200_PIC_INTS{1'b0}};

 `endif

                end

`endif

          default: begin

             spr_dat_o[`OR1200_PIC_INTS-1:0] = picsr;

`ifdef OR1200_PIC_UNUSED_ZERO

             spr_dat_o[31:`OR1200_PIC_INTS] = {32-`OR1200_PIC_INTS{1'b0}};

`endif

          end

        endcase

//

// Unmasked interrupts

//

assign um_ints = pic_int & {picmr, 2'b11};

//

// Generate intr

//

assign intr = |um_ints;

//

// Assert pic_wakeup when intr is asserted

//

assign pic_wakeup = intr;

`else

//

// When PIC is not implemented, drive all outputs as would when PIC is disabled

//

assign intr = pic_int[1] | pic_int[0];

assign pic_wakeup= intr;

//

// Read PIC registers

//

`ifdef OR1200_PIC_READREGS

assign spr_dat_o[`OR1200_PIC_INTS-1:0] = `OR1200_PIC_INTS'b0;

`ifdef OR1200_PIC_UNUSED_ZERO

assign spr_dat_o[31:`OR1200_PIC_INTS] = 32-`OR1200_PIC_INTS'b0;

`endif

`endif

`endif

endmodule