///////////////////////////////////////////
// uncore.sv
//
// Written: David_Harris@hmc.edu 9 January 2021
// Modified: Ben Bracker 6 Mar 2021 to better fit AMBA 3 AHB-Lite spec
//
// Purpose: System-on-Chip components outside the core (hart)
//          Memories, peripherals, external bus control
// 
// A component of the Wally configurable RISC-V project.
// 
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// 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.
///////////////////////////////////////////

`include "wally-config.vh"

// *** need idiom to map onto cache RAM with byte writes
// *** and use memread signal to reduce power when reads aren't needed
module uncore (
  // AHB Bus Interface
  input  logic             HCLK, HRESETn,
  input  logic [31:0]      HADDR,
  input  logic [`AHBW-1:0] HWDATAIN,
  input  logic             HWRITE,
  input  logic [2:0]       HSIZE,
  input  logic [2:0]       HBURST,
  input  logic [3:0]       HPROT,
  input  logic [1:0]       HTRANS,
  input  logic             HMASTLOCK,
  input  logic [`AHBW-1:0] HRDATAEXT,
  input  logic             HREADYEXT, HRESPEXT,
  output logic [`AHBW-1:0] HRDATA,
  output logic             HREADY, HRESP,
  // delayed signals
  input  logic [2:0]       HADDRD,
  input  logic [3:0]       HSIZED,
  input  logic             HWRITED,
  // PMA checker signals
  input  logic [5:0]       HSELRegions,
  // bus interface
  // PMA checker now handles access faults. *** This can be deleted
  // output logic             DataAccessFaultM,
  // peripheral pins
  output logic             TimerIntM, SwIntM, ExtIntM,
  input  logic [31:0]      GPIOPinsIn,
  output logic [31:0]      GPIOPinsOut, GPIOPinsEn, 
  input  logic             UARTSin,
  output logic             UARTSout,
  output logic [63:0]      MTIME_CLINT, MTIMECMP_CLINT
);
  
  logic [`XLEN-1:0] HWDATA;
  logic [`XLEN-1:0] HREADTim, HREADCLINT, HREADPLIC, HREADGPIO, HREADUART;

  logic            HSELTim, HSELCLINT, HSELPLIC, HSELGPIO, PreHSELUART, HSELUART;
  logic            HSELTimD, HSELCLINTD, HSELPLICD, HSELGPIOD, HSELUARTD;
  logic            HRESPTim, HRESPCLINT, HRESPPLIC, HRESPGPIO, HRESPUART;
  logic            HREADYTim, HREADYCLINT, HREADYPLIC, HREADYGPIO, HREADYUART;  
  logic [`XLEN-1:0] HREADBootTim; 
  logic            HSELBootTim, HSELBootTimD, HRESPBootTim, HREADYBootTim;
  logic [1:0]      MemRWboottim;
  logic            UARTIntr,GPIOIntr;

  // unswizzle HSEL signals
  assign {HSELBootTim, HSELTim, HSELCLINT, HSELGPIO, HSELUART, HSELPLIC} = HSELRegions;

  // subword accesses: converts HWDATAIN to HWDATA
  subwordwrite sww(.*);

  // tightly integrated memory
  dtim #(.BASE(`TIMBASE), .RANGE(`TIMRANGE)) dtim (.*);
  dtim #(.BASE(`BOOTTIMBASE), .RANGE(`BOOTTIMRANGE)) bootdtim(.HSELTim(HSELBootTim), .HREADTim(HREADBootTim), .HRESPTim(HRESPBootTim), .HREADYTim(HREADYBootTim), .*);

  // memory-mapped I/O peripherals
  clint clint(.HADDR(HADDR[15:0]), .MTIME(MTIME_CLINT), .MTIMECMP(MTIMECMP_CLINT), .*);
  plic plic(.HADDR(HADDR[27:0]), .*);
  gpio gpio(.HADDR(HADDR[7:0]), .*); // *** may want to add GPIO interrupts
  uart uart(.HADDR(HADDR[2:0]), .TXRDYb(), .RXRDYb(), .INTR(UARTIntr), .SIN(UARTSin), .SOUT(UARTSout),
            .DSRb(1'b1), .DCDb(1'b1), .CTSb(1'b0), .RIb(1'b1), 
            .RTSb(), .DTRb(), .OUT1b(), .OUT2b(), .*);

  // mux could also include external memory  
  // AHB Read Multiplexer
  assign HRDATA = ({`XLEN{HSELTimD}} & HREADTim) | 
                  ({`XLEN{HSELCLINTD}} & HREADCLINT) |
                  ({`XLEN{HSELPLICD}} & HREADPLIC) | 
                  ({`XLEN{HSELGPIOD}} & HREADGPIO) |
                  ({`XLEN{HSELBootTimD}} & HREADBootTim) |
                  ({`XLEN{HSELUARTD}} & HREADUART);
  assign HRESP = HSELTimD & HRESPTim |
                 HSELCLINTD & HRESPCLINT |
                 HSELPLICD & HRESPPLIC |
                 HSELGPIOD & HRESPGPIO | 
                 HSELBootTimD & HRESPBootTim |
                 HSELUARTD & HRESPUART;
  assign HREADY = HSELTimD & HREADYTim |
                  HSELCLINTD & HREADYCLINT |
                  HSELPLICD & HREADYPLIC |
                  HSELGPIOD & HREADYGPIO | 
                  HSELBootTimD & HREADYBootTim |
                  HSELUARTD & HREADYUART;

  /* PMA checker now handles access faults. *** This can be deleted
  // Faults
  assign DataAccessFaultM = ~(HSELTimD | HSELCLINTD | HSELPLICD | HSELGPIOD | HSELBootTimD | HSELUARTD);
  */

  // Address Decoder Delay (figure 4-2 in spec)
  flopr #(1) hseltimreg(HCLK, ~HRESETn, HSELTim, HSELTimD);
  flopr #(1) hselclintreg(HCLK, ~HRESETn, HSELCLINT, HSELCLINTD);
  flopr #(1) hselplicreg(HCLK, ~HRESETn, HSELPLIC, HSELPLICD);
  flopr #(1) hselgpioreg(HCLK, ~HRESETn, HSELGPIO, HSELGPIOD);
  flopr #(1) hseluartreg(HCLK, ~HRESETn, HSELUART, HSELUARTD);
  flopr #(1) hselboottimreg(HCLK, ~HRESETn, HSELBootTim, HSELBootTimD);
endmodule