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/*
* Copyright (c) 2024 Athena Systems LLC and Ian Marco Moffett
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Description: Platform Interrupt Message Controller
* Author: Ian Moffett
*/
module pimc #(
parameter IRQ_PIN_COUNT = 16,
parameter IRQTAB_ENTSIZE = 32,
parameter IRQTAB_MMIOBASE = 48'h1000
) (
input wire clk, /* 50 MHz */
input logic [IRQ_PIN_COUNT-1:0] irq_in,
input logic irqack,
/* MMIO interface */
input logic [47:0] mmio_addr,
output logic [31:0] mmio_rdata,
input wire mmio_re,
output logic notify,
output logic [7:0] lineno,
output logic [7:0] processor_id
);
integer i;
bit accept;
bit irqmask;
reg [IRQTAB_ENTSIZE - 1:0] irqtab[IRQ_PIN_COUNT];
initial begin
for (i = 0; i < IRQ_PIN_COUNT; i = i + IRQTAB_ENTSIZE) begin
irqtab[i] = 32'b0;
end
mmio_rdata = 32'b0;
end
always @(posedge clk) begin
/* Handle MMIO reads */
if (mmio_re) begin
case (mmio_addr)
IRQTAB_MMIOBASE: mmio_rdata <= irqtab[0];
IRQTAB_MMIOBASE + 4: mmio_rdata <= irqtab[1];
IRQTAB_MMIOBASE + 8: mmio_rdata <= irqtab[2];
IRQTAB_MMIOBASE + 12: mmio_rdata <= irqtab[3];
IRQTAB_MMIOBASE + 16: mmio_rdata <= irqtab[4];
IRQTAB_MMIOBASE + 20: mmio_rdata <= irqtab[5];
IRQTAB_MMIOBASE + 24: mmio_rdata <= irqtab[6];
IRQTAB_MMIOBASE + 28: mmio_rdata <= irqtab[7];
IRQTAB_MMIOBASE + 32: mmio_rdata <= irqtab[8];
IRQTAB_MMIOBASE + 36: mmio_rdata <= irqtab[9];
IRQTAB_MMIOBASE + 40: mmio_rdata <= irqtab[10];
IRQTAB_MMIOBASE + 44: mmio_rdata <= irqtab[11];
IRQTAB_MMIOBASE + 48: mmio_rdata <= irqtab[12];
IRQTAB_MMIOBASE + 52: mmio_rdata <= irqtab[13];
IRQTAB_MMIOBASE + 56: mmio_rdata <= irqtab[14];
IRQTAB_MMIOBASE + 60: mmio_rdata <= irqtab[15];
endcase
end
if (irqack == 1'b1) begin
lineno <= 8'b0;
notify <= 1'b1;
processor_id <= 8'b0;
end else begin
for (i = 0; i < IRQ_PIN_COUNT; i = i + 1) begin
/* IRQ should be dropped if masked */
irqmask <= irqtab[i * IRQTAB_ENTSIZE][8];
accept <= (irqmask == 1'b0 && notify == 1'b1);
if (irq_in[i] == 1'b1 && accept == 1'b1) begin
lineno <= i[7:0];
notify <= 1'b0;
processor_id <= irqtab[i * IRQTAB_ENTSIZE][7:0];
end
end
end
end
endmodule
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