// ========== Copyright Header Begin ==========================================
// 
// OpenSPARC T2 Processor File: ucb_monitor.vr
// Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved
// 4150 Network Circle, Santa Clara, California 95054, U.S.A.
//
// * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; version 2 of the License.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
// 
// For the avoidance of doubt, and except that if any non-GPL license 
// choice is available it will apply instead, Sun elects to use only 
// the General Public License version 2 (GPLv2) at this time for any 
// software where a choice of GPL license versions is made 
// available with the language indicating that GPLv2 or any later version 
// may be used, or where a choice of which version of the GPL is applied is 
// otherwise unspecified. 
//
// Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 
// CA 95054 USA or visit www.sun.com if you need additional information or 
// have any questions. 
// 
// ========== Copyright Header End ============================================
#include <vera_defines.vrh>
#include <ListMacros.vrh>         // Vera's linked list
#include "std_display_class.vrh"
#include "ucb_defines.vri"
#include "ucb___packet.vrh"
#include "ucb_top.vri"

// creating a list. NOTE: it's a macro, so no ';'
MakeVeraList(UCB___packet)

class UCB_monitor {
  //---public vars---
  event req_begin;     // triggered when NCU starts a new request
  event rsp_begin;     // triggered when target blk starts a response to NCU
  event req_end;       // triggered when NCU completes a request. Also, req_pkt is updated
  event rsp_end;       // triggered when target blk completes a response. Also, rsp_pkt is updated.
  integer ignore_err = 0;  // ignore all errors
  //---ports and classes---
  local UCB_port ucb_port;   // UCB port
  local StandardDisplay dbg; // Standard display for printing
  //---local vars---
  local string  dispScope;   // for standard display
  local integer bus_width;   // width of data bus. Valid values: 4 or 8 bits    
  local bit [127:0] req_pkt; // the latest request pkt which is updated when a new req is completed
  local bit [127:0] rsp_pkt; // the latest response pkt which is updated when a new rsp is completed
  VeraList_UCB___packet pend_rd_reqs;  // list of pending read requests
  local bit [7:0] g_asi;     // global addr identifier (ie. [39:32] of PA or UCB pkt bits [54:47])
  local integer ntransfer;   // number of data transfers for one req/rsp (ie. 128/bus_width)
  local integer num_req;     // number of requests
  local integer num_rsp;     // number of responses
  local integer running;     // init to 0. Set to 1 when this monitor starts
  local integer error_cnt;         // Error count. Init to 0. WARN: become negative if exeed max integer
  local integer max_error_printed; // stop print out error message when (error_cnt > max_error_printed)
  local integer semaphore_id;      // semaphore for accessing Vera list pend_rd_reqs

  //---public subroutines---
  task new(string dispScope="UCB_monitor", StandardDisplay dbg, UCB_port ucb_port, integer bus_width, bit [7:0] g_asi, integer start_it=0);
  task start();  // start the monitor. Do nothing if the monitor is already running
  function UCB___packet get_req_pkt();
  function UCB___packet get_rsp_pkt();
  function integer get_error_cnt()   { get_error_cnt = this.error_cnt; }
  task ignore_errors() { this.ignore_err = 1; }

  //--- local subroutines ---
  local task monitor_req();   // monitor the request bus
  local task monitor_rsp();   // monitor the response bus
  local function bit [127:0] get_request_pkt();   // return this.req_pkt
  local function bit [127:0] get_response_pkt();  // return this.rsp_pkt
  task print_error_msg(integer err_cnt, string error_msg);
}

//################################################################
//######### implementation of subroutines              ###########
//################################################################

task UCB_monitor::new(string dispScope="UCB_monitor", StandardDisplay dbg, UCB_port ucb_port, integer bus_width, bit [7:0] g_asi, integer start_it=0) {
  //---from arg list---
  this.dispScope = dispScope;
  this.dbg = dbg;
  this.ucb_port = ucb_port;
  this.bus_width = bus_width;
  this.g_asi = g_asi;
  //---the rest---
  this.req_pkt = 128'h0;     // init to bad value
  this.rsp_pkt = 128'h0;     // init to bad value
  this.pend_rd_reqs = new(); // empty list
  this.ntransfer = 128 / bus_width;
  this.num_req = 0;
  this.num_rsp = 0;
  this.running = 0;  // monitor is not running yet
  this.error_cnt = 0;
  this.max_error_printed = 10;
  semaphore_id = alloc(SEMAPHORE, 0, 1, 1); // 0: semaphore ID, 1: semaphore count, 1: one key initially
  if (semaphore_id == 0)
    dbg.dispmon(this.dispScope, MON_ERR, "alloc(SEMAPHORE, 0, 1, 1) : failed");

  //---sanity check---
  if ((bus_width != 4) && (bus_width != 8)) {
    dbg.dispmon(this.dispScope, MON_ERR, psprintf("ucb bus width %0d <= monitor only supports 4/8-bit bus", this.bus_width));
    this.error_cnt++;
  }
  //---start back ground threads---
  if (start_it)
    this.start();  // start the monitor
}

//==========================================================
// WHAT: start the monitor
//==========================================================
task UCB_monitor::start() {
  if (running) {
    return;      // monitor is already running
  }
  dbg.dispmon(this.dispScope, MON_INFO, "UCB monitor starts");
  fork { monitor_req(); } join none
  fork { monitor_rsp(); } join none
  running = 1; // monitor is now running
}

//==========================================================
// WHAT: monitor the requests from NCU to target unit.
// WARNING: per NCU and UCB specs, NCU must deassert ncu_xxx_vld
//    for at least one cycle before sending the next request.
//==========================================================
task UCB_monitor::monitor_req() {
  while (1) {
    @(posedge ucb_port.$req_vld);      // wait for new request
    this.num_req++;
    trigger(this.req_begin);           // inform the caller
    this.req_pkt = get_request_pkt();  // get the pkt
    trigger(this.req_end);             // inform the caller
  }
}

//==========================================================
// WHAT: monitor the response from target unit to NCU.
// WARNING: per NCU and UCB specs, target unit must deassert
//    xxx_ncu_vld for at least one cycle before sending the next response.
//==========================================================
task UCB_monitor::monitor_rsp() {
  while (1) {
    @(posedge ucb_port.$rsp_vld);       // wait for new response
    this.num_rsp++;
    trigger(this.rsp_begin);            // inform the caller
    this.rsp_pkt = get_response_pkt();  // get the pkt
    trigger(this.rsp_end);              // inform the caller
  }
}

//==========================================================
// WHAT: get the request packet (ie. 128-bit pkt NCU sends to target block
// WARNING: per NCU and UCB specs, NCU must deassert ncu_xxx_vld
//    for at least one cycle before sending the next request.
//==========================================================
function bit [127:0] UCB_monitor::get_request_pkt() {
  integer i, lsb=0, req_err_cnt = 0;
  bit [127:0] data;
  string pkt_type_str;
  UCB___packet pkt;

  //---get req pkt from the bus---
  fork {
    @(negedge ucb_port.$req_vld);
    dbg.dispmon(this.dispScope, MON_ERR, "NCU deasserts ncu_xxx_vld before ucb req pkt completed");
  }
  {
    for (i = 0; i < this.ntransfer; i++) {
      if (ucb_port.$req_stall == 1'b1)
        @(negedge ucb_port.$req_stall);
      data[lsb + bus_width - 1 : lsb] = ucb_port.$req_data;
      if (i != (this.ntransfer - 1))  // not the last data transfer
        @(posedge ucb_port.$clk);
      lsb = lsb + bus_width;          // for next data transfer
    }
  } join any
  terminate;
  //--- NCU must deassert ncu_xxx_vld for at least one cycle----
  fork {
    @(posedge ucb_port.$clk);
    if (ucb_port.$req_vld != 1'b0)
      dbg.dispmon(this.dispScope, MON_ERR, "NCU does not deassert ncu_xxx_vld after request completed");
  } join none
  //---print out req for info---
  pkt = new(*, data);
  case (pkt.pkt_type) {
    UCB_PKT_READ_REQ:  pkt_type_str = "rd req";
    UCB_PKT_WRITE_REQ: pkt_type_str = "wr req";
    default: pkt_type_str = "unkown req";
  }
  dbg.dispmon(this.dispScope, MON_INFO, psprintf("%s : addr=0x%h, payload=0x%h, threadID=0x%h, cpuID=0x%h, bufferID=0x%h",
    pkt_type_str, pkt.addr, pkt.payload, pkt.thread_id, pkt.cpu_id, pkt.buffer_id));
  //---check for protocol/restriction violations---
  if (pkt.req_size !== UCB_PKT_REQSIZE__8B)
    print_error_msg(req_err_cnt++,  psprintf("ucb req pkt=0x%h <= not 8B req", data));
  if ((pkt.pkt_type != UCB_PKT_READ_REQ) && (pkt.pkt_type != UCB_PKT_WRITE_REQ))
    print_error_msg(req_err_cnt++,  psprintf("ucb req pkt=0x%h <= not rd/wr req", data));
  if (pkt.addr[39:32] != this.g_asi)
    print_error_msg(req_err_cnt++, psprintf("ucb req pkt=0x%h <= global asi or [54:47] is not 0x%h ", data, this.g_asi));
  if ((pkt.buffer_id != 2'b00) && (pkt.buffer_id != 2'b01))
    print_error_msg(req_err_cnt++, psprintf("ucb req pkt=0x%h <= buffer ID or [11:10] is bad", data));
  //---for read request---
  if (pkt.pkt_type == UCB_PKT_READ_REQ) {
    void = semaphore_get(WAIT, semaphore_id, 1);  // only one thread can access pending rd list.
    this.pend_rd_reqs.push_back(pkt);             // add new rd req to the end of the list
    semaphore_put(semaphore_id, 1);
  }
  //---return value---
  get_request_pkt = data;
}

//==========================================================
// WHAT: get the response packet (ie. 128-bit pkt target block sent to NCU)
// WARNING: per NCU and UCB specs, target unit must deassert
//    xxx_ncu_vld for at least one cycle before sending the next response.
//==========================================================
function bit [127:0] UCB_monitor::get_response_pkt() {
  integer i, lsb=0, rsp_err_cnt=0;
  bit [127:0] data;
  bit [3:0] pkt_type;
  string pkt_type_str;
  UCB___packet pkt, oldest_rd_pkt;
  integer is_rd_nack=0;  // 1: read_nack rsp, 0: not a read_nack rsp
  integer nbits=0;       // number of bits transferred

  //--- sanity check ---
  if (pend_rd_reqs.size() < 1)
    print_error_msg(0, "got rd rsp, but there is no pending rd req");
  //---get response pkt---
  fork {
    @(negedge ucb_port.$rsp_vld);
    dbg.dispmon(this.dispScope, MON_ERR, "target unit deasserts *_ncu_vld before completing rd response pkt");
  }
  {
    for (i = 0; i < this.ntransfer; i++) {
      if (ucb_port.$rsp_stall == 1'b1)
        @(negedge ucb_port.$rsp_stall);
      data[lsb + bus_width - 1 : lsb] = ucb_port.$rsp_data;
      nbits += this.bus_width;
      //---check for READ_NACK---
      if (i == 0) {
        pkt_type = data[UCB_PKT_PKTTYPE__MSB:UCB_PKT_PKTTYPE__LSB];
        case (pkt_type) {
          UCB_PKT_READ_ACK  : is_rd_nack = 0;
          UCB_PKT_READ_NACK : is_rd_nack = 1;
          default :
            print_error_msg(rsp_err_cnt++, psprintf("ucb rsp pkt type=0x%h <= not READ_ACK nor READ_NACK rsp", pkt_type));
        }
      }
      //---for next data transfer---
      if ((is_rd_nack) && (nbits >= 64))
        break; // in read_nack, client sends UCB pkt without payload (ie. 64-bit pkt only)
      if (i != (this.ntransfer - 1))  // not the last response
        @(posedge ucb_port.$clk);
      lsb = lsb + bus_width;
    }
  } join any
  terminate;
  //---- target unit must deassert xxx_ncu_vld for at least one cycle---
  fork {
    @(negedge ucb_port.$clk);
    if (ucb_port.$rsp_vld != 1'b0)
      dbg.dispmon(this.dispScope, MON_ERR, "target unit does not deassert *_ncu_vld after rd response completed");
  } join none
  //----print out rsp pkt for info----
  pkt = new(*, data);
  case (pkt.pkt_type) {
    UCB_PKT_READ_ACK  : pkt_type_str = "rd rsp";
    UCB_PKT_READ_NACK : pkt_type_str = "rd nack";
    default:            pkt_type_str = "unkown rsp";
  }
  dbg.dispmon(this.dispScope, MON_INFO, psprintf("%s : payload=0x%h, threadID=0x%h, cpuID=0x%h, bufferID=0x%h",
    pkt_type_str, pkt.payload, pkt.thread_id, pkt.cpu_id, pkt.buffer_id));
  //---check rsp pkt header matches rd req pkt---
  if (pend_rd_reqs.size() > 0) {  // check only when there is a pending rd req
    void = semaphore_get(WAIT, semaphore_id, 1);  // only one thread can access pending rd list.
    oldest_rd_pkt = pend_rd_reqs.front();
    if (pkt.buffer_id != oldest_rd_pkt.buffer_id)
      print_error_msg(0, psprintf("ucb rsp pkt=0x%h, req pkt=0x%h <= buffer ID or [11:10] not matched", data, oldest_rd_pkt.pkt));
    if (pkt.cpu_id != oldest_rd_pkt.cpu_id)
      print_error_msg(0, psprintf("ucb rsp pkt=0x%h, req pkt=0x%h <= CPU ID or [9:7] not matched", data, oldest_rd_pkt.pkt));
    if (pkt.thread_id != oldest_rd_pkt.thread_id)
      print_error_msg(0, psprintf("ucb rsp pkt=0x%h, req pkt=0x%h <= thread ID or [6:4] not matched", data, oldest_rd_pkt.pkt));
    pend_rd_reqs.pop_front();  // remove oldest pending read req from list, no matter rsp matches or not
    semaphore_put(semaphore_id, 1);
  }
  //---rd req is now completed---
  get_response_pkt = data;
}

//=============================================================
// WHAT: print error message
// NOTE:
//   err_cnt is local error count of a particular error type.
//   this.error_cnt is global error count of this vera class.
//=============================================================
task UCB_monitor::print_error_msg(integer err_cnt, string error_msg) {
  this.error_cnt++; // increment global error count
  if (this.ignore_err)
    return;
  if (err_cnt <= max_error_printed)
    dbg.dispmon(this.dispScope, MON_ERR, error_msg);
}

//=============================================================
// Return the req pkt to the caller
//=============================================================
function UCB___packet UCB_monitor::get_req_pkt() {
  UCB___packet ucb_pkt = new(*, this.req_pkt); // create a separate copy
  get_req_pkt = ucb_pkt;
}

//=============================================================
// Return rsp pkt to the caller
//=============================================================
function UCB___packet UCB_monitor::get_rsp_pkt() {
  UCB___packet ucb_pkt = new(*, this.rsp_pkt); // create a separate copy
  get_rsp_pkt = ucb_pkt;
}