Bochs/bochs/iodev/usb_uhci.cc

/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
//  Copyright (C) 2009  Benjamin D Lunt (fys at frontiernet net)
//
//  This library 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 of the License, or (at your option) any later version.
//
//  This library 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 library; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
/////////////////////////////////////////////////////////////////////////

// Experimental USB UHCI adapter

// Notes: See usb_common.cc

// Define BX_PLUGGABLE in files that can be compiled into plugins.  For
// platforms that require a special tag on exported symbols, BX_PLUGGABLE
// is used to know when we are exporting symbols and when we are importing.
#define BX_PLUGGABLE

#include "iodev.h"

#if BX_SUPPORT_PCI && BX_SUPPORT_USB_UHCI

#include "pci.h"
#include "usb_common.h"
#include "usb_uhci.h"

#define LOG_THIS theUSB_UHCI->

bx_usb_uhci_c* theUSB_UHCI = NULL;

const Bit8u uhci_iomask[32] = {2, 1, 2, 1, 2, 1, 2, 0, 4, 0, 0, 0, 1, 0, 0, 0,
                              3, 1, 3, 1, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

int libusb_uhci_LTX_plugin_init(plugin_t *plugin, plugintype_t type, int argc, char *argv[])
{
  theUSB_UHCI = new bx_usb_uhci_c();
  BX_REGISTER_DEVICE_DEVMODEL(plugin, type, theUSB_UHCI, BX_PLUGIN_USB_UHCI);
  return 0; // Success
}

void libusb_uhci_LTX_plugin_fini(void)
{
  delete theUSB_UHCI;
}

bx_usb_uhci_c::bx_usb_uhci_c()
{
  put("UHCI");
  memset((void*)&hub, 0, sizeof(bx_usb_uhci_t));
  device_buffer = NULL;
  hub.iolight_timer_index = BX_NULL_TIMER_HANDLE;
}

bx_usb_uhci_c::~bx_usb_uhci_c()
{
  char pname[16];

  if (BX_UHCI_THIS device_buffer != NULL)
    delete [] BX_UHCI_THIS device_buffer;

  for (int i=0; i<BX_N_USB_UHCI_PORTS; i++) {
    sprintf(pname, "port%d.device", i+1);
    SIM->get_param_string(pname, SIM->get_param(BXPN_USB_UHCI))->set_handler(NULL);
    remove_device(i);
  }

  BX_DEBUG(("Exit"));
}

void bx_usb_uhci_c::init(void)
{
  unsigned i;
  char pname[6];
  bx_list_c *port;
  bx_param_string_c *device, *options;

  BX_UHCI_THIS device_buffer = new Bit8u[65536];

  // Call our timer routine every 1mS (1,000uS)
  // Continuous and active
  BX_UHCI_THIS hub.timer_index =
                   bx_pc_system.register_timer(this, usb_timer_handler, 1000, 1,1, "usb.timer");

  if (DEV_is_pci_device(BX_PLUGIN_USB_UHCI)) {
    BX_UHCI_THIS hub.devfunc = 0x00;
  } else {
    BX_UHCI_THIS hub.devfunc = BX_PCI_DEVICE(1,2);
  }
  DEV_register_pci_handlers(this, &BX_UHCI_THIS hub.devfunc, BX_PLUGIN_USB_UHCI,
                            "Experimental USB UHCI");

  for (i=0; i<256; i++) {
    BX_UHCI_THIS pci_conf[i] = 0x0;
  }

  BX_UHCI_THIS pci_base_address[4] = 0x0;

  //FIXME: for now, we want a status bar // hub zero, port zero
  BX_UHCI_THIS hub.statusbar_id = bx_gui->register_statusitem("UHCI");

  bx_list_c *usb_rt = (bx_list_c*)SIM->get_param(BXPN_MENU_RUNTIME_USB);
  bx_list_c *uhci = (bx_list_c*)SIM->get_param(BXPN_USB_UHCI);
  uhci->set_options(uhci->SHOW_PARENT);
  uhci->set_runtime_param(1);
  usb_rt->add(uhci);
  for (i=0; i<BX_N_USB_UHCI_PORTS; i++) {
    sprintf(pname, "port%d", i+1);
    port = (bx_list_c*)SIM->get_param(pname, uhci);
    port->set_runtime_param(1);
    device = (bx_param_string_c*)port->get_by_name("device");
    device->set_handler(usb_param_handler);
    device->set_runtime_param(1);
    options = (bx_param_string_c*)port->get_by_name("options");
    options->set_runtime_param(1);
    BX_UHCI_THIS hub.usb_port[i].device = NULL;
  }

  //HACK: Turn on debug messages from the start
  //BX_UHCI_THIS setonoff(LOGLEV_DEBUG, ACT_REPORT);

  // register timer for i/o light
  if (BX_UHCI_THIS hub.iolight_timer_index == BX_NULL_TIMER_HANDLE) {
    BX_UHCI_THIS hub.iolight_timer_index =
      DEV_register_timer(this, iolight_timer_handler, 5000, 0,0, "UHCI i/o light");
  }
  BX_UHCI_THIS hub.iolight_counter = 0;

  // register handler for correct device connect handling after runtime config
  SIM->register_runtime_config_handler(BX_UHCI_THIS_PTR, runtime_config_handler);
  BX_UHCI_THIS hub.device_change = 0;

  BX_INFO(("USB UHCI initialized"));
}

void bx_usb_uhci_c::reset(unsigned type)
{
  unsigned i, j;
  char pname[6];

  if (type == BX_RESET_HARDWARE) {
    static const struct reset_vals_t {
      unsigned      addr;
      unsigned char val;
    } reset_vals[] = {
      { 0x00, 0x86 }, { 0x01, 0x80 }, // 0x8086 = vendor
      { 0x02, 0x20 }, { 0x03, 0x70 }, // 0x7020 = device
      { 0x04, 0x05 }, { 0x05, 0x00 }, // command_io
      { 0x06, 0x80 }, { 0x07, 0x02 }, // status
      { 0x08, 0x01 },                 // revision number
      { 0x09, 0x00 },                 // interface
      { 0x0a, 0x03 },                 // class_sub  USB Host Controller
      { 0x0b, 0x0c },                 // class_base Serial Bus Controller
      { 0x0D, 0x20 },                 // bus latency
      { 0x0e, 0x00 },                 // header_type_generic
      // address space 0x20 - 0x23
      { 0x20, 0x01 }, { 0x21, 0x00 },
      { 0x22, 0x00 }, { 0x23, 0x00 },
      { 0x3c, 0x00 },                 // IRQ
      { 0x3d, BX_PCI_INTD },          // INT
      { 0x60, 0x10 },                 // USB revision 1.0
      { 0x6a, 0x01 },                 // USB clock
      { 0xc1, 0x20 }                  // PIRQ enable

    };
    for (i = 0; i < sizeof(reset_vals) / sizeof(*reset_vals); ++i) {
        BX_UHCI_THIS pci_conf[reset_vals[i].addr] = reset_vals[i].val;
    }
  }

  // reset locals
  BX_UHCI_THIS busy = 0;
  BX_UHCI_THIS global_reset = 0;

  // Put the USB registers into their RESET state
  BX_UHCI_THIS hub.usb_command.max_packet_size = 0;
  BX_UHCI_THIS hub.usb_command.configured = 0;
  BX_UHCI_THIS hub.usb_command.debug = 0;
  BX_UHCI_THIS hub.usb_command.resume = 0;
  BX_UHCI_THIS hub.usb_command.suspend = 0;
  BX_UHCI_THIS hub.usb_command.reset = 0;
  BX_UHCI_THIS hub.usb_command.host_reset = 0;
  BX_UHCI_THIS hub.usb_command.schedule = 0;
  BX_UHCI_THIS hub.usb_status.error_interrupt = 0;
  BX_UHCI_THIS hub.usb_status.host_error = 0;
  BX_UHCI_THIS hub.usb_status.host_halted = 0;
  BX_UHCI_THIS hub.usb_status.interrupt = 0;
  BX_UHCI_THIS hub.usb_status.pci_error = 0;
  BX_UHCI_THIS hub.usb_status.resume = 0;
  BX_UHCI_THIS hub.usb_enable.short_packet = 0;
  BX_UHCI_THIS hub.usb_enable.on_complete = 0;
  BX_UHCI_THIS hub.usb_enable.resume = 0;
  BX_UHCI_THIS hub.usb_enable.timeout_crc = 0;
  BX_UHCI_THIS hub.usb_frame_num.frame_num = 0x0000;
  BX_UHCI_THIS hub.usb_frame_base.frame_base = 0x00000000;
  BX_UHCI_THIS hub.usb_sof.sof_timing = 0x40;
  for (j=0; j<BX_N_USB_UHCI_PORTS; j++) {
    BX_UHCI_THIS hub.usb_port[j].connect_changed = 0;
    BX_UHCI_THIS hub.usb_port[j].line_dminus = 0;
    BX_UHCI_THIS hub.usb_port[j].line_dplus = 0;
    BX_UHCI_THIS hub.usb_port[j].low_speed = 0;
    BX_UHCI_THIS hub.usb_port[j].reset = 0;
    BX_UHCI_THIS hub.usb_port[j].resume = 0;
    BX_UHCI_THIS hub.usb_port[j].suspend = 0;
    BX_UHCI_THIS hub.usb_port[j].enabled = 0;
    BX_UHCI_THIS hub.usb_port[j].able_changed = 0;
    BX_UHCI_THIS hub.usb_port[j].status = 0;
    if (BX_UHCI_THIS hub.usb_port[j].device == NULL) {
      sprintf(pname, "port%d", j+1);
      init_device(j, (bx_list_c*)SIM->get_param(pname, SIM->get_param(BXPN_USB_UHCI)));
    } else {
      usb_set_connect_status(j, BX_UHCI_THIS hub.usb_port[j].device->get_type(), 1);
    }
  }

}

void bx_usb_uhci_c::register_state(void)
{
  unsigned j;
  char portnum[8];
  bx_list_c *hub, *usb_cmd, *usb_st, *usb_en, *port;

  bx_list_c *list = new bx_list_c(SIM->get_bochs_root(), "usb_uhci", "USB UHCI State");
  hub = new bx_list_c(list, "hub", BX_N_USB_UHCI_PORTS + 7);
  usb_cmd = new bx_list_c(hub, "usb_command", 8);
  new bx_shadow_bool_c(usb_cmd, "max_packet_size", &BX_UHCI_THIS hub.usb_command.max_packet_size);
  new bx_shadow_bool_c(usb_cmd, "configured", &BX_UHCI_THIS hub.usb_command.configured);
  new bx_shadow_bool_c(usb_cmd, "debug", &BX_UHCI_THIS hub.usb_command.debug);
  new bx_shadow_bool_c(usb_cmd, "resume", &BX_UHCI_THIS hub.usb_command.resume);
  new bx_shadow_bool_c(usb_cmd, "suspend", &BX_UHCI_THIS hub.usb_command.suspend);
  new bx_shadow_bool_c(usb_cmd, "reset", &BX_UHCI_THIS hub.usb_command.reset);
  new bx_shadow_bool_c(usb_cmd, "host_reset", &BX_UHCI_THIS hub.usb_command.host_reset);
  new bx_shadow_bool_c(usb_cmd, "schedule", &BX_UHCI_THIS hub.usb_command.schedule);
  usb_st = new bx_list_c(hub, "usb_status", 6);
  new bx_shadow_bool_c(usb_st, "host_halted", &BX_UHCI_THIS hub.usb_status.host_halted);
  new bx_shadow_bool_c(usb_st, "host_error", &BX_UHCI_THIS hub.usb_status.host_error);
  new bx_shadow_bool_c(usb_st, "pci_error", &BX_UHCI_THIS hub.usb_status.pci_error);
  new bx_shadow_bool_c(usb_st, "resume", &BX_UHCI_THIS hub.usb_status.resume);
  new bx_shadow_bool_c(usb_st, "error_interrupt", &BX_UHCI_THIS hub.usb_status.error_interrupt);
  new bx_shadow_bool_c(usb_st, "interrupt", &BX_UHCI_THIS hub.usb_status.interrupt);
  usb_en = new bx_list_c(hub, "usb_enable", 4);
  new bx_shadow_bool_c(usb_en, "short_packet", &BX_UHCI_THIS hub.usb_enable.short_packet);
  new bx_shadow_bool_c(usb_en, "on_complete", &BX_UHCI_THIS hub.usb_enable.on_complete);
  new bx_shadow_bool_c(usb_en, "resume", &BX_UHCI_THIS hub.usb_enable.resume);
  new bx_shadow_bool_c(usb_en, "timeout_crc", &BX_UHCI_THIS hub.usb_enable.timeout_crc);
  new bx_shadow_num_c(hub, "frame_num", &BX_UHCI_THIS hub.usb_frame_num.frame_num, BASE_HEX);
  new bx_shadow_num_c(hub, "frame_base", &BX_UHCI_THIS hub.usb_frame_base.frame_base, BASE_HEX);
  new bx_shadow_num_c(hub, "sof_timing", &BX_UHCI_THIS hub.usb_sof.sof_timing, BASE_HEX);
  for (j=0; j<BX_N_USB_UHCI_PORTS; j++) {
    sprintf(portnum, "port%d", j+1);
    port = new bx_list_c(hub, portnum, 11);
    new bx_shadow_bool_c(port, "suspend", &BX_UHCI_THIS hub.usb_port[j].suspend);
    new bx_shadow_bool_c(port, "reset", &BX_UHCI_THIS hub.usb_port[j].reset);
    new bx_shadow_bool_c(port, "low_speed", &BX_UHCI_THIS hub.usb_port[j].low_speed);
    new bx_shadow_bool_c(port, "resume", &BX_UHCI_THIS hub.usb_port[j].resume);
    new bx_shadow_bool_c(port, "line_dminus", &BX_UHCI_THIS hub.usb_port[j].line_dminus);
    new bx_shadow_bool_c(port, "line_dplus", &BX_UHCI_THIS hub.usb_port[j].line_dplus);
    new bx_shadow_bool_c(port, "able_changed", &BX_UHCI_THIS hub.usb_port[j].able_changed);
    new bx_shadow_bool_c(port, "enabled", &BX_UHCI_THIS hub.usb_port[j].enabled);
    new bx_shadow_bool_c(port, "connect_changed", &BX_UHCI_THIS hub.usb_port[j].connect_changed);
    new bx_shadow_bool_c(port, "status", &BX_UHCI_THIS hub.usb_port[j].status);
    // empty list for USB device state
    new bx_list_c(port, "device", 20);
  }
  register_pci_state(hub);

  new bx_shadow_bool_c(list, "busy", &BX_UHCI_THIS busy);
  new bx_shadow_num_c(list, "global_reset", &BX_UHCI_THIS global_reset);
}

void bx_usb_uhci_c::after_restore_state(void)
{
  if (DEV_pci_set_base_io(BX_UHCI_THIS_PTR, read_handler, write_handler,
                         &BX_UHCI_THIS pci_base_address[4],
                         &BX_UHCI_THIS pci_conf[0x20],
                         32, &uhci_iomask[0], "USB UHCI Hub"))
  {
     BX_INFO(("new base address: 0x%04x", BX_UHCI_THIS pci_base_address[4]));
  }
  for (int j=0; j<BX_N_USB_UHCI_PORTS; j++) {
    if (BX_UHCI_THIS hub.usb_port[j].device != NULL) {
      BX_UHCI_THIS hub.usb_port[j].device->after_restore_state();
    }
  }
}

void bx_usb_uhci_c::init_device(Bit8u port, bx_list_c *portconf)
{
  usbdev_type type;
  char pname[BX_PATHNAME_LEN];
  const char *devname = NULL;

  devname = ((bx_param_string_c*)portconf->get_by_name("device"))->getptr();
  if (devname == NULL) return;
  if (!strlen(devname) || !strcmp(devname, "none")) return;

  if (BX_UHCI_THIS hub.usb_port[port].device != NULL) {
    BX_ERROR(("init_device(): port%d already in use", port+1));
    return;
  }
  sprintf(pname, "usb_uhci.hub.port%d.device", port+1);
  bx_list_c *sr_list = (bx_list_c*)SIM->get_param(pname, SIM->get_bochs_root());
  type = DEV_usb_init_device(portconf, BX_UHCI_THIS_PTR, &BX_UHCI_THIS hub.usb_port[port].device, sr_list);
  if (BX_UHCI_THIS hub.usb_port[port].device != NULL) {
    usb_set_connect_status(port, type, 1);
  }
}

void bx_usb_uhci_c::remove_device(Bit8u port)
{
  char pname[BX_PATHNAME_LEN];

  if (BX_UHCI_THIS hub.usb_port[port].device != NULL) {
    delete BX_UHCI_THIS hub.usb_port[port].device;
    BX_UHCI_THIS hub.usb_port[port].device = NULL;
    sprintf(pname, "usb_uhci.hub.port%d.device", port+1);
    bx_list_c *devlist = (bx_list_c*)SIM->get_param(pname, SIM->get_bochs_root());
    devlist->clear();
  }
}

void bx_usb_uhci_c::set_irq_level(bx_bool level)
{
  DEV_pci_set_irq(BX_UHCI_THIS hub.devfunc, BX_UHCI_THIS pci_conf[0x3d], level);
}

// static IO port read callback handler
// redirects to non-static class handler to avoid virtual functions

Bit32u bx_usb_uhci_c::read_handler(void *this_ptr, Bit32u address, unsigned io_len)
{
#if !BX_USE_USB_UHCI_SMF
  bx_usb_uhci_c *class_ptr = (bx_usb_uhci_c *) this_ptr;
  return class_ptr->read(address, io_len);
}

Bit32u bx_usb_uhci_c::read(Bit32u address, unsigned io_len)
{
#else
  UNUSED(this_ptr);
#endif // !BX_USE_USB_UHCI_SMF
  Bit32u val = 0x0;
  Bit8u  offset,port;

  offset = address - BX_UHCI_THIS pci_base_address[4];

  switch (offset) {
    case 0x00: // command register (16-bit)
      val =   BX_UHCI_THIS hub.usb_command.max_packet_size << 7
            | BX_UHCI_THIS hub.usb_command.configured << 6
            | BX_UHCI_THIS hub.usb_command.debug << 5
            | BX_UHCI_THIS hub.usb_command.resume << 4
            | BX_UHCI_THIS hub.usb_command.suspend << 3
            | BX_UHCI_THIS hub.usb_command.reset << 2
            | BX_UHCI_THIS hub.usb_command.host_reset << 1
            | BX_UHCI_THIS hub.usb_command.schedule;
      break;

    case 0x02: // status register (16-bit)
      val = BX_UHCI_THIS hub.usb_status.host_halted << 5
            | BX_UHCI_THIS hub.usb_status.host_error << 4
            | BX_UHCI_THIS hub.usb_status.pci_error << 3
            | BX_UHCI_THIS hub.usb_status.resume << 2
            | BX_UHCI_THIS hub.usb_status.error_interrupt << 1
            | BX_UHCI_THIS hub.usb_status.interrupt;
      break;

    case 0x04: // interrupt enable register (16-bit)
      val = BX_UHCI_THIS hub.usb_enable.short_packet << 3
            | BX_UHCI_THIS hub.usb_enable.on_complete << 2
            | BX_UHCI_THIS hub.usb_enable.resume << 1
            | BX_UHCI_THIS hub.usb_enable.timeout_crc;
      break;

    case 0x06: // frame number register (16-bit)
      val = BX_UHCI_THIS hub.usb_frame_num.frame_num;
      break;

    case 0x08: // frame base register (32-bit)
      val = BX_UHCI_THIS hub.usb_frame_base.frame_base;
      break;

    case 0x0C: // start of Frame Modify register (8-bit)
      val = BX_UHCI_THIS hub.usb_sof.sof_timing;
      break;

    case 0x14: // port #3 non existant, but linux systems check it to see if there are more than 2
      BX_ERROR(("read from non existant offset 0x14 (port #3)"));
      val = 0xFF7F;
      break;

    case 0x10: // port #1
    case 0x11:
    case 0x12: // port #2
    case 0x13:
      port = (offset & 0x0F) >> 1;
      if (port < BX_N_USB_UHCI_PORTS) {
        val = BX_UHCI_THIS hub.usb_port[port].suspend << 12
              |                                       1 << 10  // some Root Hubs have bit 10 set ?????
              | BX_UHCI_THIS hub.usb_port[port].reset << 9
              | BX_UHCI_THIS hub.usb_port[port].low_speed << 8
              | 1 << 7
              | BX_UHCI_THIS hub.usb_port[port].resume << 6
              | BX_UHCI_THIS hub.usb_port[port].line_dminus << 5
              | BX_UHCI_THIS hub.usb_port[port].line_dplus << 4
              | BX_UHCI_THIS hub.usb_port[port].able_changed << 3
              | BX_UHCI_THIS hub.usb_port[port].enabled << 2
              | BX_UHCI_THIS hub.usb_port[port].connect_changed << 1
              | BX_UHCI_THIS hub.usb_port[port].status;
        if (offset & 1) val >>= 8;
        break;
      } // else fall through to default
    default:
      val = 0xFF7F; // keep compiler happy
      BX_ERROR(("unsupported io read from address=0x%04x!", (unsigned) address));
      break;
  }

  BX_DEBUG(("register read from address 0x%04X:  0x%08X (%2i bits)", (unsigned) address, (Bit32u) val, io_len * 8));

  return(val);
}

// static IO port write callback handler
// redirects to non-static class handler to avoid virtual functions

void bx_usb_uhci_c::write_handler(void *this_ptr, Bit32u address, Bit32u value, unsigned io_len)
{
#if !BX_USE_USB_UHCI_SMF
  bx_usb_uhci_c *class_ptr = (bx_usb_uhci_c *) this_ptr;
  class_ptr->write(address, value, io_len);
}

void bx_usb_uhci_c::write(Bit32u address, Bit32u value, unsigned io_len)
{
#else
  UNUSED(this_ptr);
#endif // !BX_USE_USB_UHCI_SMF
  Bit8u  offset,port;

  BX_DEBUG(("register write to  address 0x%04X:  0x%08X (%2i bits)", (unsigned) address, (unsigned) value, io_len * 8));

  offset = address - BX_UHCI_THIS pci_base_address[4];

  switch (offset) {
    case 0x00: // command register (16-bit) (R/W)
      if (value & 0xFF00)
        BX_DEBUG(("write to command register with bits 15:8 not zero: 0x%04x", value));

      BX_UHCI_THIS hub.usb_command.max_packet_size = (value & 0x80) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.configured = (value & 0x40) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.debug = (value & 0x20) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.resume = (value & 0x10) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.suspend = (value & 0x08) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.reset = (value & 0x04) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.host_reset = (value & 0x02) ? 1: 0;
      BX_UHCI_THIS hub.usb_command.schedule = (value & 0x01) ? 1: 0;

      // HCRESET
      if (BX_UHCI_THIS hub.usb_command.host_reset) {
        BX_UHCI_THIS reset(0);
        for (unsigned i=0; i<BX_N_USB_UHCI_PORTS; i++) {
          if (BX_UHCI_THIS hub.usb_port[i].status) {
            if (BX_UHCI_THIS hub.usb_port[i].device != NULL) {
              DEV_usb_send_msg(BX_UHCI_THIS hub.usb_port[i].device, USB_MSG_RESET);
            }
          }
          BX_UHCI_THIS hub.usb_port[i].connect_changed = 1;
          BX_UHCI_THIS hub.usb_port[i].enabled = 0;
          BX_UHCI_THIS hub.usb_port[i].able_changed = 1;
        }
      }

      // If software set the GRESET bit, we need to send the reset to all USB.
      // The software should guarentee that the reset is for at least 10ms.
      // We hold the reset until software resets this bit
      if (BX_UHCI_THIS hub.usb_command.reset) {
        BX_UHCI_THIS global_reset = 1;
        BX_DEBUG(("Global Reset"));
      } else {
        // if software cleared the reset, then we need to reset the usb registers.
        if (BX_UHCI_THIS global_reset) {
          BX_UHCI_THIS global_reset = 0;
          unsigned int running = BX_UHCI_THIS hub.usb_command.schedule;
          BX_UHCI_THIS reset(0);
          BX_UHCI_THIS hub.usb_status.host_halted = (running) ? 1 : 0;
        }
      }

      // If Run/Stop, identify in log
      if (BX_UHCI_THIS hub.usb_command.schedule) {
        BX_UHCI_THIS hub.usb_status.host_halted = 0;
        BX_DEBUG(("Schedule bit set in Command register"));
      } else {
        BX_UHCI_THIS hub.usb_status.host_halted = 1;
        BX_DEBUG(("Schedule bit clear in Command register"));
      }

      // If Debug mode set, panic.  Not implemented
      if (BX_UHCI_THIS hub.usb_command.debug)
        BX_PANIC(("Software set DEBUG bit in Command register. Not implemented"));

      break;

    case 0x02: // status register (16-bit) (R/WC)
      if (value & 0xFFC0)
        BX_DEBUG(("write to status register with bits 15:6 not zero: 0x%04x", value));

      // host_halted, even though not specified in the specs, is read only
      //BX_UHCI_THIS hub.usb_status.host_halted = (value & 0x20) ? 0: BX_UHCI_THIS hub.usb_status.host_halted;
      BX_UHCI_THIS hub.usb_status.host_error = (value & 0x10) ? 0: BX_UHCI_THIS hub.usb_status.host_error;
      BX_UHCI_THIS hub.usb_status.pci_error = (value & 0x08) ? 0: BX_UHCI_THIS hub.usb_status.pci_error;
      BX_UHCI_THIS hub.usb_status.resume = (value & 0x04) ? 0: BX_UHCI_THIS hub.usb_status.resume;
      BX_UHCI_THIS hub.usb_status.error_interrupt = (value & 0x02) ? 0: BX_UHCI_THIS hub.usb_status.error_interrupt;
      BX_UHCI_THIS hub.usb_status.interrupt = (value & 0x01) ? 0: BX_UHCI_THIS hub.usb_status.interrupt;
      break;

    case 0x04: // interrupt enable register (16-bit)
      if (value & 0xFFF0)
        BX_DEBUG(("write to interrupt enable register with bits 15:4 not zero: 0x%04x", value));

      BX_UHCI_THIS hub.usb_enable.short_packet  = (value & 0x08) ? 1: 0;
      BX_UHCI_THIS hub.usb_enable.on_complete  = (value & 0x04) ? 1: 0;
      BX_UHCI_THIS hub.usb_enable.resume  = (value & 0x02) ? 1: 0;
      BX_UHCI_THIS hub.usb_enable.timeout_crc = (value & 0x01) ? 1: 0;

      if (value & 0x08) {
        BX_DEBUG(("Host set Enable Interrupt on Short Packet"));
      }
      if (value & 0x04) {
        BX_DEBUG(("Host set Enable Interrupt on Complete"));
      }
      if (value & 0x02) {
        BX_DEBUG(("Host set Enable Interrupt on Resume"));
      }
      break;

    case 0x06: // frame number register (16-bit)
      if (value & 0xF800)
        BX_DEBUG(("write to frame number register with bits 15:11 not zero: 0x%04x", value));

      if (BX_UHCI_THIS hub.usb_status.host_halted)
        BX_UHCI_THIS hub.usb_frame_num.frame_num = (value & 0x07FF);
      else
        // ignored by the hardward, but lets report it anyway
        BX_DEBUG(("write to frame number register with STATUS.HALTED == 0"));
      break;

    case 0x08: // frame base register (32-bit)
      if (value & 0xFFF)
        BX_DEBUG(("write to frame base register with bits 11:0 not zero: 0x%08x", value));

      BX_UHCI_THIS hub.usb_frame_base.frame_base = (value & ~0xfff);
      break;

    case 0x0C: // start of Frame Modify register (8-bit)
      if (value & 0x80)
        BX_DEBUG(("write to SOF Modify register with bit 7 not zero: 0x%04x", value));

       BX_UHCI_THIS hub.usb_sof.sof_timing = value;
       break;

    case 0x14: // port #3 non existant, but linux systems check it to see if there are more than 2
      BX_ERROR(("write to non existant offset 0x14 (port #3)"));
      break;

    case 0x10: // port #1
    case 0x12: // port #2
      port = (offset & 0x0F) >> 1;
      if ((port < BX_N_USB_UHCI_PORTS) && (io_len == 2)) {
        // If the ports reset bit is set, don't allow any writes unless the new write will clear the reset bit
        if (BX_UHCI_THIS hub.usb_port[port].reset & (value & (1<<9)))
          break;
        if (value & ((1<<5) | (1<<4) | (1<<0)))
          BX_DEBUG(("write to one or more read-only bits in port #%d register: 0x%04x", port+1, value));
        if (!(value & (1<<7)))
          BX_DEBUG(("write to port #%d register bit 7 = 0", port+1));
        if (value & (1<<8))
          BX_DEBUG(("write to bit 8 in port #%d register ignored", port+1));
        if ((value & (1<<12)) && BX_UHCI_THIS hub.usb_command.suspend)
          BX_DEBUG(("write to port #%d register bit 12 when in Global-Suspend", port+1));

        BX_UHCI_THIS hub.usb_port[port].suspend = (value & (1<<12)) ? 1 : 0;
        BX_UHCI_THIS hub.usb_port[port].reset = (value & (1<<9)) ? 1 : 0;
        BX_UHCI_THIS hub.usb_port[port].resume = (value & (1<<6)) ? 1 : 0;
        if (!BX_UHCI_THIS hub.usb_port[port].enabled && (value & (1<<2)))
          BX_UHCI_THIS hub.usb_port[port].able_changed = 0;
        else
          BX_UHCI_THIS hub.usb_port[port].able_changed = (value & (1<<3)) ? 0 : BX_UHCI_THIS hub.usb_port[port].able_changed;
        BX_UHCI_THIS hub.usb_port[port].enabled = (value & (1<<2)) ? 1 : 0;
        BX_UHCI_THIS hub.usb_port[port].connect_changed = (value & (1<<1)) ? 0 : BX_UHCI_THIS hub.usb_port[port].connect_changed;

        // if port reset, reset function(s)
        //TODO: only reset items on the downstream...
        // for now, reset the one and only
        // TODO: descriptors, etc....
        if (BX_UHCI_THIS hub.usb_port[port].reset) {
          BX_UHCI_THIS hub.usb_port[port].suspend = 0;
          BX_UHCI_THIS hub.usb_port[port].resume = 0;
          BX_UHCI_THIS hub.usb_port[port].enabled = 0;
          // are we are currently connected/disconnected
          if (BX_UHCI_THIS hub.usb_port[port].status) {
            if (BX_UHCI_THIS hub.usb_port[port].device != NULL) {
              BX_UHCI_THIS hub.usb_port[port].low_speed =
                (BX_UHCI_THIS hub.usb_port[port].device->get_speed() == USB_SPEED_LOW);
              usb_set_connect_status(port, BX_UHCI_THIS hub.usb_port[port].device->get_type(), 1);
              DEV_usb_send_msg(BX_UHCI_THIS hub.usb_port[port].device, USB_MSG_RESET);
            }
          }
          BX_INFO(("Port%d: Reset", port+1));
        }
        break;
      }
      // else fall through to default
    default:
      BX_ERROR(("unsupported io write to address=0x%04x!", (unsigned) address));
      break;
  }
}

void bx_usb_uhci_c::usb_timer_handler(void *this_ptr)
{
  bx_usb_uhci_c *class_ptr = (bx_usb_uhci_c *) this_ptr;
  class_ptr->usb_timer();
}

// Called once every 1ms
#define USB_STACK_SIZE  256
void bx_usb_uhci_c::usb_timer(void)
{
  int i;

  // If the "global reset" bit was set by software
  if (BX_UHCI_THIS global_reset) {
    for (i=0; i<BX_N_USB_UHCI_PORTS; i++) {
      BX_UHCI_THIS hub.usb_port[i].able_changed = 0;
      BX_UHCI_THIS hub.usb_port[i].connect_changed = 0;
      BX_UHCI_THIS hub.usb_port[i].enabled = 0;
      BX_UHCI_THIS hub.usb_port[i].line_dminus = 0;
      BX_UHCI_THIS hub.usb_port[i].line_dplus = 0;
      BX_UHCI_THIS hub.usb_port[i].low_speed = 0;
      BX_UHCI_THIS hub.usb_port[i].reset = 0;
      BX_UHCI_THIS hub.usb_port[i].resume = 0;
      BX_UHCI_THIS hub.usb_port[i].status = 0;
      BX_UHCI_THIS hub.usb_port[i].suspend = 0;
    }
    return;
  }

  // If command.schedule = 1, then run schedule
  //  *** This assumes that we can complete the frame within the 1ms time allowed ***
  // Actually, not complete, but reach the end of the frame.  This means that there may still
  //  be TDs and QHs that were BREADTH defined and will be executed on the next cycle/iteration.

  if (BX_UHCI_THIS busy) {
    BX_PANIC(("Did not complete last frame before the 1ms was over. Starting next frame."));
    BX_UHCI_THIS busy = 0;
  }
  if (BX_UHCI_THIS hub.usb_command.schedule) {
    BX_UHCI_THIS busy = 1;
    bx_bool fire_int = 0;
    set_irq_level(0);  // make sure it is low
    bx_bool interrupt = 0, shortpacket = 0, stalled = 0;
    struct TD td;
    struct HCSTACK stack[USB_STACK_SIZE+1];  // queue stack for this item only
    Bit32s stk = 0;
    Bit32u item, address, lastvertaddr = 0, queue_num = 0;
    Bit32u frame, frm_addr = BX_UHCI_THIS hub.usb_frame_base.frame_base +
                                (BX_UHCI_THIS hub.usb_frame_num.frame_num << 2);
    DEV_MEM_READ_PHYSICAL(frm_addr, 4, (Bit8u*) &frame);
    if ((frame & 1) == 0) {
      stack[stk].next = (frame & ~0xF);
      stack[stk].d = 0;
      stack[stk].q = (frame & 0x0002) ? 1 : 0;
      stack[stk].t = 0;
      while (stk > -1) {

        // Linux seems to just loop a few queues together and wait for the 1ms to end.
        // We will just count the stack and exit when we get to a good point to stop.
        if (stk >= USB_STACK_SIZE) break;

        // check to make sure we are not done before continue-ing on
        if ((stack[stk].d == HC_VERT) && stack[stk].t) { stk--; continue; }
        if ((stack[stk].d == HC_HORZ) && stack[stk].t) break;
        if (stack[stk].q) { // is a queue
          address = stack[stk].next;
          lastvertaddr = address + 4;
          // get HORZ slot
          stk++;
          DEV_MEM_READ_PHYSICAL(address, 4, (Bit8u*) &item);
          stack[stk].next = item & ~0xF;
          stack[stk].d = HC_HORZ;
          stack[stk].q = (item & 0x0002) ? 1 : 0;
          stack[stk].t = (item & 0x0001) ? 1 : 0;
          // get VERT slot
          stk++;
          DEV_MEM_READ_PHYSICAL(lastvertaddr, 4, (Bit8u*) &item);
          stack[stk].next = item & ~0xF;
          stack[stk].d = HC_VERT;
          stack[stk].q = (item & 0x0002) ? 1 : 0;
          stack[stk].t = (item & 0x0001) ? 1 : 0;
          BX_DEBUG(("Queue %3i: 0x%08X %i %i  0x%08X %i %i", queue_num,
            stack[stk-1].next, stack[stk-1].q, stack[stk-1].t,
            stack[stk].next, stack[stk].q, stack[stk].t));
          queue_num++;
        } else {  // else is a TD
          address = stack[stk].next;
          DEV_MEM_READ_PHYSICAL(address,    4, (Bit8u*) &td.dword0);
          DEV_MEM_READ_PHYSICAL(address+4,  4, (Bit8u*) &td.dword1);
          DEV_MEM_READ_PHYSICAL(address+8,  4, (Bit8u*) &td.dword2);
          DEV_MEM_READ_PHYSICAL(address+12, 4, (Bit8u*) &td.dword3);
          bx_bool spd = (td.dword1 & (1<<29)) ? 1 : 0;
          stack[stk].next = td.dword0 & ~0xF;
          bx_bool depthbreadth = (td.dword0 & 0x0004) ? 1 : 0;     // 1 = depth first, 0 = breadth first
          stack[stk].q = (td.dword0 & 0x0002) ? 1 : 0;
          stack[stk].t = (td.dword0 & 0x0001) ? 1 : 0;
          if (td.dword1 & (1<<24)) interrupt = 1;
          if (td.dword1 & (1<<23)) {  // is it an active TD
            BX_DEBUG(("Frame: %04i (0x%04X)", BX_UHCI_THIS hub.usb_frame_num.frame_num, BX_UHCI_THIS hub.usb_frame_num.frame_num));
            if (BX_UHCI_THIS DoTransfer(address, queue_num, &td)) {
              // issue short packet?
              Bit16u r_actlen = (((td.dword1 & 0x7FF)+1) & 0x7FF);
              Bit16u r_maxlen = (((td.dword2>>21)+1) & 0x7FF);
              BX_DEBUG((" r_actlen = 0x%04X r_maxlen = 0x%04X", r_actlen, r_maxlen));
              if (((td.dword2 & 0xFF) == USB_TOKEN_IN) && spd && stk && (r_actlen < r_maxlen) && ((td.dword1 & 0x00FF0000) == 0)) {
                shortpacket = 1;
                td.dword1 |= (1<<29);
              }
              if (td.dword1 & (1<<22)) stalled = 1;

              DEV_MEM_WRITE_PHYSICAL(address+4, 4, (Bit8u*) &td.dword1);  // write back the status
              if (shortpacket) {
                td.dword0 |= 1;
                stack[stk].t = 1;
              }
              // copy pointer for next queue item, in to vert queue head
              if ((stk > 0) && (stack[stk].d == HC_VERT))
                DEV_MEM_WRITE_PHYSICAL(lastvertaddr, 4, (Bit8u*) &td.dword0);
            }
          }

          if (stk > 0) {
            // if last TD in HORZ queue pointer, then we are done.
            if (stack[stk].t && (stack[stk].d == HC_HORZ)) break;
            // if Breadth first or last item in queue, move to next queue.
            if (!depthbreadth || stack[stk].t) {
              if (stack[stk].d == HC_HORZ) queue_num--;  // <-- really, this should never happen until we
              stk--;                                     //           support bandwidth reclamation...
            }
            if (stk < 1) break;
          } else {
            if (stack[stk].t) break;
          }

        }
      }

      // set the status register bit:0 to 1 if SPD is enabled
      // and if interrupts not masked via interrupt register, raise irq interrupt.
      if (shortpacket && BX_UHCI_THIS hub.usb_enable.short_packet) {
        fire_int = 1;
        BX_DEBUG((" [SPD] We want it to fire here (Frame: %04i)", BX_UHCI_THIS hub.usb_frame_num.frame_num));
      }

      // if one of the TD's in this frame had the ioc bit set, we need to
      //   raise an interrupt, if interrupts are not masked via interrupt register.
      //   always set the status register if IOC.
      if (interrupt && BX_UHCI_THIS hub.usb_enable.on_complete) {
        fire_int = 1;
        BX_DEBUG((" [IOC] We want it to fire here (Frame: %04i)", BX_UHCI_THIS hub.usb_frame_num.frame_num));
      }

      if (stalled && BX_UHCI_THIS hub.usb_enable.timeout_crc) {
        fire_int = 1;
        BX_DEBUG((" [stalled] We want it to fire here (Frame: %04i)", BX_UHCI_THIS hub.usb_frame_num.frame_num));
      }
    }

    // The Frame Number Register is incremented every 1ms
    BX_UHCI_THIS hub.usb_frame_num.frame_num++;
    BX_UHCI_THIS hub.usb_frame_num.frame_num &= (1024-1);

    // if we needed to fire an interrupt now, lets do it *after* we increment the frame_num register
    if (fire_int) {
      BX_UHCI_THIS hub.usb_status.interrupt = 1;
      BX_UHCI_THIS hub.usb_status.error_interrupt = stalled;
      set_irq_level(1);
    }

    // The status.interrupt bit should be set regardless of the enable bits if a IOC or SPD is found
    if (shortpacket || interrupt)
      BX_UHCI_THIS hub.usb_status.interrupt = 1;

    BX_UHCI_THIS busy = 0;  // ready to do next frame item
  }  // end run schedule

  // if host turned off the schedule, set the halted bit in the status register
  // Note: Can not use an else from the if() above since the host can changed this bit
  //  while we are processing a frame.
  if (BX_UHCI_THIS hub.usb_command.schedule == 0)
    BX_UHCI_THIS hub.usb_status.host_halted = 1;

  // TODO:
  //  If in Global_Suspend mode and any of usb_port[i] bits 6,3, or 1 are set,
  //    we need to issue a Global_Resume (set the global resume bit).
  //    However, since we don't do anything, let's not.
}

bx_bool bx_usb_uhci_c::DoTransfer(Bit32u address, Bit32u queue_num, struct TD *td) {

  int len = 0, ret = 0;

  Bit16u maxlen = (td->dword2 >> 21);
  Bit8u  addr   = (td->dword2 >> 8) & 0x7F;
  Bit8u  endpt  = (td->dword2 >> 15) & 0x0F;
  Bit8u  pid    =  td->dword2 & 0xFF;

  BX_DEBUG(("QH%03i:TD found at address: 0x%08X", queue_num, address));
  BX_DEBUG(("  %08X   %08X   %08X   %08X", td->dword0, td->dword1, td->dword2, td->dword3));

  // check TD to make sure it is valid
  // A max length 0x500 to 0x77E is illegal
  if (((td->dword2 >> 21) >= 0x500) && ((td->dword2 >> 21) != 0x7FF)) {
    BX_ERROR(("error at 11111111111"));
    return 1;  // error = consistency check failure
  }

  //if (td->dword0 & 0x8) return 1; // error = reserved bits in dword0 set
  // other error checks here

  // the device should remain in a stall state until the next setup packet is recieved
  // For some reason, this doesn't work yet.
  //if (dev && dev->in_stall && (pid != USB_TOKEN_SETUP))
  //  return FALSE;

  maxlen++;
  maxlen &= 0x7FF;

  /* set status bar conditions for device */
  if (maxlen > 0) {
    if (!BX_UHCI_THIS hub.iolight_counter) {
      if (pid == USB_TOKEN_OUT)
        bx_gui->statusbar_setitem(BX_UHCI_THIS hub.statusbar_id, 1, 1);  // write
      else
        bx_gui->statusbar_setitem(BX_UHCI_THIS hub.statusbar_id, 1);     // read
    }
    BX_UHCI_THIS hub.iolight_counter = 5;
    bx_pc_system.activate_timer(BX_UHCI_THIS hub.iolight_timer_index, 5000, 0);
  }

  BX_UHCI_THIS usb_packet.pid = pid;
  BX_UHCI_THIS usb_packet.devaddr = addr;
  BX_UHCI_THIS usb_packet.devep = endpt;
  BX_UHCI_THIS usb_packet.data = device_buffer;
  BX_UHCI_THIS usb_packet.len = maxlen;
  switch (pid) {
    case USB_TOKEN_OUT:
    case USB_TOKEN_SETUP:
      if (maxlen > 0) {
        DEV_MEM_READ_PHYSICAL_DMA(td->dword3, maxlen, device_buffer);
      }
      ret = BX_UHCI_THIS broadcast_packet(&BX_UHCI_THIS usb_packet);
      len = maxlen;
      break;
    case USB_TOKEN_IN:
      ret = BX_UHCI_THIS broadcast_packet(&BX_UHCI_THIS usb_packet);
      if (ret >= 0) {
        len = ret;
        if (len > maxlen) {
          len = maxlen;
          ret = USB_RET_BABBLE;
        }
        if (len > 0) {
          DEV_MEM_WRITE_PHYSICAL_DMA(td->dword3, len, device_buffer);
        }
      } else {
        len = 0;
      }
      break;
    default:
      BX_UHCI_THIS hub.usb_status.host_error = 1;
      BX_UHCI_THIS set_irq_level(1);
  }
  if (ret >= 0) {
    BX_UHCI_THIS set_status(td, 0, 0, 0, 0, 0, 0, len-1);
  } else {
    BX_UHCI_THIS set_status(td, 1, 0, 0, 0, 0, 0, 0x007); // stalled
  }
  return 1;
}

int bx_usb_uhci_c::broadcast_packet(USBPacket *p)
{
  int i, ret;

  ret = USB_RET_NODEV;
  for (i = 0; i < BX_N_USB_UHCI_PORTS && ret == USB_RET_NODEV; i++) {
    if ((BX_UHCI_THIS hub.usb_port[i].device != NULL) &&
        (BX_UHCI_THIS hub.usb_port[i].enabled)) {
      ret = BX_UHCI_THIS hub.usb_port[i].device->handle_packet(p);
    }
  }
  return ret;
}

// If the request fails, set the stall bit ????
void bx_usb_uhci_c::set_status(struct TD *td, bx_bool stalled, bx_bool data_buffer_error, bx_bool babble,
                             bx_bool nak, bx_bool crc_time_out, bx_bool bitstuff_error, Bit16u act_len)
{
  // clear out the bits we can modify and/or want zero
  td->dword1 &= 0xDF00F800;

  // now set the bits according to the passed param's
  td->dword1 |= stalled           ? (1<<22) : 0; // stalled
  td->dword1 |= data_buffer_error ? (1<<21) : 0; // data buffer error
  td->dword1 |= babble            ? (1<<20) : 0; // babble
  td->dword1 |= nak               ? (1<<19) : 0; // nak
  td->dword1 |= crc_time_out      ? (1<<18) : 0; // crc/timeout
  td->dword1 |= bitstuff_error    ? (1<<17) : 0; // bitstuff error
  td->dword1 |= (act_len & 0x7FF);               // actual length
  if (stalled || data_buffer_error || babble || nak || crc_time_out || bitstuff_error)
    td->dword1 &= ~((1<<28) | (1<<27));  // clear the c_err field in there was an error
}

void bx_usb_uhci_c::iolight_timer_handler(void *this_ptr)
{
  bx_usb_uhci_c *class_ptr = (bx_usb_uhci_c *) this_ptr;
  class_ptr->iolight_timer();
}

void bx_usb_uhci_c::iolight_timer()
{
  if (BX_UHCI_THIS hub.iolight_counter > 0) {
    if (--BX_UHCI_THIS hub.iolight_counter)
      bx_pc_system.activate_timer(BX_UHCI_THIS hub.iolight_timer_index, 5000, 0);
    else
      bx_gui->statusbar_setitem(BX_UHCI_THIS hub.statusbar_id, 0);
  }
 }

void bx_usb_uhci_c::runtime_config_handler(void *this_ptr)
{
  bx_usb_uhci_c *class_ptr = (bx_usb_uhci_c *) this_ptr;
  class_ptr->runtime_config();
}

void bx_usb_uhci_c::runtime_config(void)
{
  int i;
  char pname[6];

  for (i = 0; i < BX_N_USB_UHCI_PORTS; i++) {
    // device change support
    if ((BX_UHCI_THIS hub.device_change & (1 << i)) != 0) {
      BX_INFO(("USB port #%d: device connect", i+1));
      sprintf(pname, "port%d", i + 1);
      init_device(i, (bx_list_c*)SIM->get_param(pname, SIM->get_param(BXPN_USB_UHCI)));
      BX_UHCI_THIS hub.device_change &= ~(1 << i);
    }
    // forward to connected device
    if (BX_UHCI_THIS hub.usb_port[i].device != NULL) {
      BX_UHCI_THIS hub.usb_port[i].device->runtime_config();
    }
  }
}

// pci configuration space read callback handler
Bit32u bx_usb_uhci_c::pci_read_handler(Bit8u address, unsigned io_len)
{
  Bit32u value = 0;

  for (unsigned i=0; i<io_len; i++) {
    value |= (BX_UHCI_THIS pci_conf[address+i] << (i*8));
  }

  if (io_len == 1)
    BX_DEBUG(("read  PCI register 0x%02x value 0x%02x", address, value));
  else if (io_len == 2)
    BX_DEBUG(("read  PCI register 0x%02x value 0x%04x", address, value));
  else if (io_len == 4)
    BX_DEBUG(("read  PCI register 0x%02x value 0x%08x", address, value));

  return value;
}


// pci configuration space write callback handler
void bx_usb_uhci_c::pci_write_handler(Bit8u address, Bit32u value, unsigned io_len)
{
  Bit8u value8, oldval;
  bx_bool baseaddr_change = 0;

  if (((address >= 0x10) && (address < 0x20)) ||
      ((address > 0x23) && (address < 0x34)))
    return;

  for (unsigned i=0; i<io_len; i++) {
    value8 = (value >> (i*8)) & 0xFF;
    oldval = BX_UHCI_THIS pci_conf[address+i];
    switch (address+i) {
      case 0x04:
        value8 &= 0x05;
        BX_UHCI_THIS pci_conf[address+i] = value8;
        break;
      case 0x3d: //
      case 0x3e: //
      case 0x3f: //
      case 0x05: // disallowing write to command hi-byte
      case 0x06: // disallowing write to status lo-byte (is that expected?)
        break;
      case 0x3c:
        if (value8 != oldval) {
          BX_INFO(("new irq line = %d", value8));
          BX_UHCI_THIS pci_conf[address+i] = value8;
        }
        break;
      case 0x20:
        value8 = (value8 & 0xfc) | 0x01;
      case 0x21:
      case 0x22:
      case 0x23:
        baseaddr_change |= (value8 != oldval);
      default:
        BX_UHCI_THIS pci_conf[address+i] = value8;
    }
  }
  if (baseaddr_change) {
    if (DEV_pci_set_base_io(BX_UHCI_THIS_PTR, read_handler, write_handler,
                            &BX_UHCI_THIS pci_base_address[4],
                            &BX_UHCI_THIS pci_conf[0x20],
                            32, &uhci_iomask[0], "USB UHCI Hub")) {
      BX_INFO(("new base address: 0x%04x", BX_UHCI_THIS pci_base_address[4]));
    }
  }

  if (io_len == 1)
    BX_DEBUG(("write PCI register 0x%02x value 0x%02x", address, value));
  else if (io_len == 2)
    BX_DEBUG(("write PCI register 0x%02x value 0x%04x", address, value));
  else if (io_len == 4)
    BX_DEBUG(("write PCI register 0x%02x value 0x%08x", address, value));
}

void bx_usb_uhci_c::usb_set_connect_status(Bit8u port, int type, bx_bool connected)
{
  usb_device_c *device = BX_UHCI_THIS hub.usb_port[port].device;
  if (device != NULL) {
    if (device->get_type() == type) {
      if (connected) {
        BX_UHCI_THIS hub.usb_port[port].low_speed =
          (device->get_speed() == USB_SPEED_LOW);
        if (BX_UHCI_THIS hub.usb_port[port].low_speed) {
          BX_UHCI_THIS hub.usb_port[port].line_dminus = 1;  //  dminus=1 & dplus=0 = low speed  (at idle time)
          BX_UHCI_THIS hub.usb_port[port].line_dplus = 0;   //  dminus=0 & dplus=1 = high speed (at idle time)
        } else {
          BX_UHCI_THIS hub.usb_port[port].line_dminus = 0;
          BX_UHCI_THIS hub.usb_port[port].line_dplus = 1;
        }
        BX_UHCI_THIS hub.usb_port[port].status = 1;
        BX_UHCI_THIS hub.usb_port[port].connect_changed = 1;
        BX_UHCI_THIS hub.usb_port[port].able_changed = 1;

        // if in suspend state, signal resume
        if (BX_UHCI_THIS hub.usb_command.suspend) {
          BX_UHCI_THIS hub.usb_port[port].resume = 1;
          BX_UHCI_THIS hub.usb_status.resume = 1;
          if (BX_UHCI_THIS hub.usb_enable.resume) {
            BX_UHCI_THIS hub.usb_status.interrupt = 1;
            set_irq_level(1);
          }
        }

        if (!device->get_connected()) {
          if (!device->init()) {
            usb_set_connect_status(port, type, 0);
            BX_ERROR(("port #%d: connect failed", port+1));
          } else {
            BX_INFO(("port #%d: connect: %s", port+1, device->get_info()));
          }
        }
      } else {
        BX_UHCI_THIS hub.usb_port[port].status = 0;
        BX_UHCI_THIS hub.usb_port[port].connect_changed = 1;
        BX_UHCI_THIS hub.usb_port[port].enabled = 0;
        BX_UHCI_THIS hub.usb_port[port].able_changed = 1;
        BX_UHCI_THIS hub.usb_port[port].low_speed = 0;
        BX_UHCI_THIS hub.usb_port[port].line_dminus = 0;
        BX_UHCI_THIS hub.usb_port[port].line_dplus = 0;
        remove_device(port);
      }
    }
  }
}

// USB runtime parameter handler
const char *bx_usb_uhci_c::usb_param_handler(bx_param_string_c *param, int set,
                                           const char *oldval, const char *val, int maxlen)
{
  usbdev_type type = USB_DEV_TYPE_NONE;
  int portnum;

  if (set) {
    portnum = atoi((param->get_parent())->get_name()+4) - 1;
    bx_bool empty = ((strlen(val) == 0) || (!strcmp(val, "none")));
    if ((portnum >= 0) && (portnum < BX_N_USB_UHCI_PORTS)) {
      if (empty && BX_UHCI_THIS hub.usb_port[portnum].status) {
        BX_INFO(("USB port #%d: device disconnect", portnum+1));
        if (BX_UHCI_THIS hub.usb_port[portnum].device != NULL) {
          type = BX_UHCI_THIS hub.usb_port[portnum].device->get_type();
        }
        usb_set_connect_status(portnum, type, 0);
      } else if (!empty && !BX_UHCI_THIS hub.usb_port[portnum].status) {
        BX_UHCI_THIS hub.device_change |= (1 << portnum);
      }
    } else {
      BX_PANIC(("usb_param_handler called with unexpected parameter '%s'", param->get_name()));
    }
  }
  return val;
}

#endif // BX_SUPPORT_PCI && BX_SUPPORT_USB_UHCI