tinyusb/src/host/usbh.c

/**************************************************************************/
/*!
    @file     usbd_host.c
    @author   hathach (tinyusb.org)

    @section LICENSE

    Software License Agreement (BSD License)

    Copyright (c) 2013, hathach (tinyusb.org)
    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 holders 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 ''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 HOLDER 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.

    This file is part of the tinyusb stack.
*/
/**************************************************************************/

#include "common/tusb_common.h"

#if TUSB_OPT_HOST_ENABLED

#define _TINY_USB_SOURCE_FILE_

#ifndef CFG_TUH_TASK_QUEUE_SZ
#define CFG_TUH_TASK_QUEUE_SZ   16
#endif

#ifndef CFG_TUH_TASK_STACK_SZ
#define CFG_TUH_TASK_STACK_SZ 200
#endif

#ifndef CFG_TUH_TASK_PRIO
#define CFG_TUH_TASK_PRIO 0
#endif


//--------------------------------------------------------------------+
// INCLUDE
//--------------------------------------------------------------------+
#include "tusb.h"
#include "hub.h"
#include "usbh_hcd.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF
//--------------------------------------------------------------------+
static host_class_driver_t const usbh_class_drivers[] =
{
  #if CFG_TUH_CDC
    {
      .class_code = TUSB_CLASS_CDC,
      .init       = cdch_init,
      .open       = cdch_open,
      .isr        = cdch_isr,
      .close      = cdch_close
    },
  #endif

  #if CFG_TUH_MSC
    {
      .class_code = TUSB_CLASS_MSC,
      .init       = msch_init,
      .open       = msch_open,
      .isr        = msch_isr,
      .close      = msch_close
    },
  #endif

  #if HOST_CLASS_HID
    {
      .class_code = TUSB_CLASS_HID,
      .init       = hidh_init,
      .open       = hidh_open_subtask,
      .isr        = hidh_isr,
      .close      = hidh_close
    },
  #endif

  #if CFG_TUH_HUB
    {
      .class_code = TUSB_CLASS_HUB,
      .init       = hub_init,
      .open       = hub_open,
      .isr        = hub_isr,
      .close      = hub_close
    },
  #endif

  #if CFG_TUSB_HOST_CUSTOM_CLASS
    {
      .class_code = TUSB_CLASS_VENDOR_SPECIFIC,
      .init       = cush_init,
      .open       = cush_open_subtask,
      .isr        = cush_isr,
      .close      = cush_close
    }
  #endif
};

enum { USBH_CLASS_DRIVER_COUNT = sizeof(usbh_class_drivers) / sizeof(host_class_driver_t) };

//--------------------------------------------------------------------+
// INTERNAL OBJECT & FUNCTION DECLARATION
//--------------------------------------------------------------------+
CFG_TUSB_MEM_SECTION usbh_device_t _usbh_devices[CFG_TUSB_HOST_DEVICE_MAX+1]; // including zero-address

OSAL_TASK_DEF(_usbh_task_def, "usbh", usbh_task, CFG_TUH_TASK_PRIO, CFG_TUH_TASK_STACK_SZ);

// Event queue
// role device/host is used by OS NONE for mutex (disable usb isr) only
OSAL_QUEUE_DEF(OPT_MODE_HOST, _usbh_qdef, CFG_TUH_TASK_QUEUE_SZ, hcd_event_t);
static osal_queue_t _usbh_q;

CFG_TUSB_MEM_SECTION ATTR_ALIGNED(4) static uint8_t _usbh_ctrl_buf[CFG_TUSB_HOST_ENUM_BUFFER_SIZE];

//------------- Reporter Task Data -------------//

//------------- Helper Function Prototypes -------------//
static inline uint8_t get_new_address(void) ATTR_ALWAYS_INLINE;
static inline uint8_t get_configure_number_for_device(tusb_desc_device_t* dev_desc) ATTR_ALWAYS_INLINE;
static void mark_interface_endpoint(uint8_t ep2drv[8][2], uint8_t const* p_desc, uint16_t desc_len, uint8_t driver_id);

//--------------------------------------------------------------------+
// PUBLIC API (Parameter Verification is required)
//--------------------------------------------------------------------+
tusb_device_state_t tuh_device_get_state (uint8_t const dev_addr)
{
  TU_ASSERT( dev_addr <= CFG_TUSB_HOST_DEVICE_MAX, TUSB_DEVICE_STATE_INVALID_PARAMETER);
  return (tusb_device_state_t) _usbh_devices[dev_addr].state;
}

//--------------------------------------------------------------------+
// CLASS-USBD API (don't require to verify parameters)
//--------------------------------------------------------------------+
bool usbh_init(void)
{
  tu_memclr(_usbh_devices, sizeof(usbh_device_t)*(CFG_TUSB_HOST_DEVICE_MAX+1));

  //------------- Enumeration & Reporter Task init -------------//
  _usbh_q = osal_queue_create( &_usbh_qdef );
  TU_ASSERT(_usbh_q != NULL);

  osal_task_create(&_usbh_task_def);

  //------------- Semaphore, Mutex for Control Pipe -------------//
  for(uint8_t i=0; i<CFG_TUSB_HOST_DEVICE_MAX+1; i++) // including address zero
  {
    usbh_device_t * const dev = &_usbh_devices[i];

    dev->control.sem_hdl = osal_semaphore_create(&dev->control.sem_def);
    TU_ASSERT(dev->control.sem_hdl != NULL);

    dev->control.mutex_hdl = osal_mutex_create(&dev->control.mutex_def);
    TU_ASSERT(dev->control.mutex_hdl != NULL);

    memset(dev->itf2drv, 0xff, sizeof(dev->itf2drv)); // invalid mapping
    memset(dev->ep2drv , 0xff, sizeof(dev->ep2drv )); // invalid mapping
  }

  // Class drivers init
  for (uint8_t drv_id = 0; drv_id < USBH_CLASS_DRIVER_COUNT; drv_id++) usbh_class_drivers[drv_id].init();

  TU_ASSERT(hcd_init());
  hcd_int_enable(TUH_OPT_RHPORT);

  return true;
}

//------------- USBH control transfer -------------//
bool usbh_control_xfer (uint8_t dev_addr, tusb_control_request_t* request, uint8_t* data)
{
  usbh_device_t* dev = &_usbh_devices[dev_addr];
  const uint8_t rhport = dev->rhport;

  TU_ASSERT(osal_mutex_lock(dev->control.mutex_hdl, OSAL_TIMEOUT_NORMAL));

  dev->control.request = *request;
  dev->control.pipe_status = 0;

  // Setup Stage
  hcd_setup_send(rhport, dev_addr, (uint8_t*) &dev->control.request);
  TU_VERIFY(osal_semaphore_wait(dev->control.sem_hdl, OSAL_TIMEOUT_NORMAL));

  // Data stage : first data toggle is always 1
  if ( request->wLength )
  {
    hcd_edpt_xfer(rhport, dev_addr, edpt_addr(0, request->bmRequestType_bit.direction), data, request->wLength);
    TU_VERIFY(osal_semaphore_wait(dev->control.sem_hdl, OSAL_TIMEOUT_NORMAL));
  }

  // Status : data toggle is always 1
  hcd_edpt_xfer(rhport, dev_addr, edpt_addr(0, 1-request->bmRequestType_bit.direction), NULL, 0);
  TU_VERIFY(osal_semaphore_wait(dev->control.sem_hdl, OSAL_TIMEOUT_NORMAL));

  osal_mutex_unlock(dev->control.mutex_hdl);

  if ( XFER_RESULT_STALLED == dev->control.pipe_status ) return false;
  if ( XFER_RESULT_FAILED == dev->control.pipe_status ) return false;

  return true;
}

tusb_error_t usbh_pipe_control_open(uint8_t dev_addr, uint8_t max_packet_size)
{
  osal_semaphore_reset( _usbh_devices[dev_addr].control.sem_hdl );
  //osal_mutex_reset( usbh_devices[dev_addr].control.mutex_hdl );
      
  tusb_desc_endpoint_t ep0_desc =
  {
    .bLength          = sizeof(tusb_desc_endpoint_t),
    .bDescriptorType  = TUSB_DESC_ENDPOINT,
    .bEndpointAddress = 0,
    .bmAttributes     = { .xfer = TUSB_XFER_CONTROL },
    .wMaxPacketSize   = { .size = max_packet_size },
    .bInterval        = 0
  };

  hcd_edpt_open(_usbh_devices[dev_addr].rhport, dev_addr, &ep0_desc);

  return TUSB_ERROR_NONE;
}

static inline tusb_error_t usbh_pipe_control_close(uint8_t dev_addr)
{
  hcd_edpt_close(_usbh_devices[dev_addr].rhport, dev_addr, 0);

  return TUSB_ERROR_NONE;
}

//--------------------------------------------------------------------+
// USBH-HCD ISR/Callback API
//--------------------------------------------------------------------+
// interrupt caused by a TD (with IOC=1) in pipe of class class_code
void hcd_event_xfer_complete(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes)
{
  usbh_device_t* dev = &_usbh_devices[ dev_addr ];

  if (0 == edpt_number(ep_addr))
  {
    dev->control.pipe_status   = event;
//    usbh_devices[ pipe_hdl.dev_addr ].control.xferred_bytes = xferred_bytes; not yet neccessary
    osal_semaphore_post( dev->control.sem_hdl, true );
  }
  else
  {
    uint8_t drv_id = dev->ep2drv[edpt_number(ep_addr)][edpt_dir(ep_addr)];
    TU_ASSERT(drv_id < USBH_CLASS_DRIVER_COUNT, );

    if (usbh_class_drivers[drv_id].isr)
    {
      usbh_class_drivers[drv_id].isr(dev_addr, ep_addr, event, xferred_bytes);
    }
    else
    {
      TU_BREAKPOINT(); // something wrong, no one claims the isr's source
    }
  }
}

void hcd_event_device_attach(uint8_t rhport)
{
  hcd_event_t event =
  {
    .rhport = rhport,
    .event_id = HCD_EVENT_DEVICE_ATTACH
  };

  event.attach.hub_addr = 0;
  event.attach.hub_port = 0;

  hcd_event_handler(&event, true);
}

void hcd_event_handler(hcd_event_t const* event, bool in_isr)
{
  switch (event->event_id)
  {
    default:
      osal_queue_send(_usbh_q, event, in_isr);
    break;
  }
}

void hcd_event_device_remove(uint8_t hostid)
{
  hcd_event_t event =
  {
    .rhport = hostid,
    .event_id = HCD_EVENT_DEVICE_REMOVE
  };

  event.attach.hub_addr = 0;
  event.attach.hub_port = 0;

  hcd_event_handler(&event, true);
}


// a device unplugged on hostid, hub_addr, hub_port
// return true if found and unmounted device, false if cannot find
static void usbh_device_unplugged(uint8_t rhport, uint8_t hub_addr, uint8_t hub_port)
{
  bool is_found = false;

  //------------- find the all devices (star-network) under port that is unplugged -------------//
  for (uint8_t dev_addr = 0; dev_addr <= CFG_TUSB_HOST_DEVICE_MAX; dev_addr ++)
  {
    usbh_device_t* dev = &_usbh_devices[dev_addr];

    if (dev->rhport == rhport   &&
        (hub_addr == 0 || dev->hub_addr == hub_addr) && // hub_addr == 0 & hub_port == 0 means roothub
        (hub_port == 0 || dev->hub_port == hub_port) &&
        dev->state    != TUSB_DEVICE_STATE_UNPLUG)
    {
      // Invoke callback before close driver
      if (tuh_umount_cb) tuh_umount_cb(dev_addr);

      // TODO Hub multiple level
      // Close class driver
      for (uint8_t drv_id = 0; drv_id < USBH_CLASS_DRIVER_COUNT; drv_id++) usbh_class_drivers[drv_id].close(dev_addr);

      // TODO refractor
      // set to REMOVING to allow HCD to clean up its cached data for this device
      // HCD must set this device's state to TUSB_DEVICE_STATE_UNPLUG when done
      dev->state = TUSB_DEVICE_STATE_REMOVING;

      memset(dev->itf2drv, 0xff, sizeof(dev->itf2drv)); // invalid mapping
      memset(dev->ep2drv , 0xff, sizeof(dev->ep2drv )); // invalid mapping

      usbh_pipe_control_close(dev_addr);

//      hcd_device_remove(rhport, dev_addr);

      is_found = true;
    }
  }

  // FIXME remove
  if (is_found) hcd_device_remove(_usbh_devices[0].rhport, 0);

}

//--------------------------------------------------------------------+
// ENUMERATION TASK
//--------------------------------------------------------------------+

bool enum_task(hcd_event_t* event)
{
  enum {
#if 1
    // FIXME ohci LPC1769 xpresso + debugging to have 1st control xfer to work, some kind of timing or ohci driver issue !!!
    POWER_STABLE_DELAY = 100,
    RESET_DELAY        = 500
#else
    POWER_STABLE_DELAY = 500,
    RESET_DELAY        = 200, // USB specs say only 50ms but many devices require much longer
#endif
  };

  // for OSAL_NONE local variable won't retain value after blocking service sem_wait/queue_recv
  static uint8_t configure_selected = 1; // TODO move

  usbh_device_t* dev0 = &_usbh_devices[0];
  tusb_control_request_t request;

  dev0->rhport  = event->rhport; // TODO refractor integrate to device_pool
  dev0->hub_addr = event->attach.hub_addr;
  dev0->hub_port = event->attach.hub_port;
  dev0->state    = TUSB_DEVICE_STATE_UNPLUG;

  //------------- connected/disconnected directly with roothub -------------//
  if ( dev0->hub_addr == 0)
  {
    if( hcd_port_connect_status(dev0->rhport) )
    {
      // connection event
      osal_task_delay(POWER_STABLE_DELAY); // wait until device is stable. Increase this if the first 8 bytes is failed to get

      // exit if device unplugged while delaying
      if ( !hcd_port_connect_status(dev0->rhport) ) return true;

      hcd_port_reset( dev0->rhport ); // port must be reset to have correct speed operation
      osal_task_delay(RESET_DELAY);

      dev0->speed = hcd_port_speed_get( dev0->rhport );
    }
    else
    {
      // disconnection event
      usbh_device_unplugged(dev0->rhport, 0, 0);
      return true; // restart task
    }
  }
  #if CFG_TUH_HUB
  //------------- connected/disconnected via hub -------------//
  else
  {
    //------------- Get Port Status -------------//
    request = (tusb_control_request_t ) {
          .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_OTHER, .type = TUSB_REQ_TYPE_CLASS, .direction = TUSB_DIR_IN },
          .bRequest = HUB_REQUEST_GET_STATUS,
          .wValue = 0,
          .wIndex = dev0->hub_port,
          .wLength = 4
    };
    // TODO hub refractor
    TU_VERIFY_HDLR( usbh_control_xfer( dev0->hub_addr, &request, _usbh_ctrl_buf ), hub_status_pipe_queue( dev0->hub_addr) );

    // Acknowledge Port Connection Change
    hub_port_clear_feature_subtask(dev0->hub_addr, dev0->hub_port, HUB_FEATURE_PORT_CONNECTION_CHANGE);

    hub_port_status_response_t * p_port_status;
    p_port_status = ((hub_port_status_response_t *) _usbh_ctrl_buf);

    if ( ! p_port_status->status_change.connect_status )   return true; // only handle connection change

    if ( ! p_port_status->status_current.connect_status )
    {
      // Disconnection event
      usbh_device_unplugged(dev0->rhport, dev0->hub_addr, dev0->hub_port);

      (void) hub_status_pipe_queue( dev0->hub_addr ); // done with hub, waiting for next data on status pipe
      return true; // restart task
    }
    else
    {
      // Connection Event
      TU_VERIFY_HDLR(hub_port_reset_subtask(dev0->hub_addr, dev0->hub_port),
                     hub_status_pipe_queue( dev0->hub_addr) ); // TODO hub refractor

      dev0->speed = hub_port_get_speed();

      // Acknowledge Port Reset Change
      hub_port_clear_feature_subtask(dev0->hub_addr, dev0->hub_port, HUB_FEATURE_PORT_RESET_CHANGE);
    }
  }
  #endif

  TU_ASSERT_ERR( usbh_pipe_control_open(0, 8) );
  dev0->state = TUSB_DEVICE_STATE_ADDRESSED;

  //------------- Get first 8 bytes of device descriptor to get Control Endpoint Size -------------//
  request = (tusb_control_request_t ) {
        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_DEVICE, .type = TUSB_REQ_TYPE_STANDARD, .direction = TUSB_DIR_IN },
        .bRequest = TUSB_REQ_GET_DESCRIPTOR,
        .wValue = TUSB_DESC_DEVICE << 8,
        .wIndex = 0,
        .wLength = 8
  };
  bool is_ok = usbh_control_xfer(0, &request, _usbh_ctrl_buf);

  //------------- Reset device again before Set Address -------------//
  if (dev0->hub_addr == 0)
  {
    // connected directly to roothub
    TU_ASSERT(is_ok); // TODO some slow device is observed to fail the very fist controller xfer, can try more times
    hcd_port_reset( dev0->rhport ); // reset port after 8 byte descriptor
    osal_task_delay(RESET_DELAY);
  }
  #if CFG_TUH_HUB
  else
  {
    // connected via a hub
    TU_VERIFY_HDLR(is_ok, hub_status_pipe_queue( dev0->hub_addr) ); // TODO hub refractor

    if ( hub_port_reset_subtask(dev0->hub_addr, dev0->hub_port) )
    {
      // Acknowledge Port Reset Change if Reset Successful
      hub_port_clear_feature_subtask(dev0->hub_addr, dev0->hub_port, HUB_FEATURE_PORT_RESET_CHANGE);
    }

    (void) hub_status_pipe_queue( dev0->hub_addr ); // done with hub, waiting for next data on status pipe
  }
  #endif

  //------------- Set new address -------------//
  uint8_t const new_addr = get_new_address();
  TU_ASSERT(new_addr <= CFG_TUSB_HOST_DEVICE_MAX); // TODO notify application we reach max devices

  request = (tusb_control_request_t ) {
        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_DEVICE, .type = TUSB_REQ_TYPE_STANDARD, .direction = TUSB_DIR_OUT },
        .bRequest = TUSB_REQ_SET_ADDRESS,
        .wValue = new_addr,
        .wIndex = 0,
        .wLength = 0
  };
  TU_ASSERT(usbh_control_xfer(0, &request, NULL));

  //------------- update port info & close control pipe of addr0 -------------//
  usbh_device_t* new_dev = &_usbh_devices[new_addr];
  new_dev->rhport  = dev0->rhport;
  new_dev->hub_addr = dev0->hub_addr;
  new_dev->hub_port = dev0->hub_port;
  new_dev->speed    = dev0->speed;
  new_dev->state    = TUSB_DEVICE_STATE_ADDRESSED;

  usbh_pipe_control_close(0);
  dev0->state = TUSB_DEVICE_STATE_UNPLUG;

  // open control pipe for new address
  TU_ASSERT_ERR ( usbh_pipe_control_open(new_addr, ((tusb_desc_device_t*) _usbh_ctrl_buf)->bMaxPacketSize0 ) );

  //------------- Get full device descriptor -------------//
  request = (tusb_control_request_t ) {
        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_DEVICE, .type = TUSB_REQ_TYPE_STANDARD, .direction = TUSB_DIR_IN },
        .bRequest = TUSB_REQ_GET_DESCRIPTOR,
        .wValue = TUSB_DESC_DEVICE << 8,
        .wIndex = 0,
        .wLength = 18
  };
  TU_ASSERT(usbh_control_xfer(new_addr, &request, _usbh_ctrl_buf));

  // update device info  TODO alignment issue
  new_dev->vendor_id       = ((tusb_desc_device_t*) _usbh_ctrl_buf)->idVendor;
  new_dev->product_id      = ((tusb_desc_device_t*) _usbh_ctrl_buf)->idProduct;
  new_dev->configure_count = ((tusb_desc_device_t*) _usbh_ctrl_buf)->bNumConfigurations;

  configure_selected = get_configure_number_for_device((tusb_desc_device_t*) _usbh_ctrl_buf);
  TU_ASSERT(configure_selected <= new_dev->configure_count); // TODO notify application when invalid configuration

  //------------- Get 9 bytes of configuration descriptor -------------//
  request = (tusb_control_request_t ) {
        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_DEVICE, .type = TUSB_REQ_TYPE_STANDARD, .direction = TUSB_DIR_IN },
        .bRequest = TUSB_REQ_GET_DESCRIPTOR,
        .wValue = (TUSB_DESC_CONFIGURATION << 8) | (configure_selected - 1),
        .wIndex = 0,
        .wLength = 9
  };
  TU_ASSERT( usbh_control_xfer(new_addr, &request, _usbh_ctrl_buf));

  // TODO not enough buffer to hold configuration descriptor
  TU_ASSERT( CFG_TUSB_HOST_ENUM_BUFFER_SIZE >= ((tusb_desc_configuration_t*)_usbh_ctrl_buf)->wTotalLength );

  //------------- Get full configuration descriptor -------------//
  request.wLength = ((tusb_desc_configuration_t*)_usbh_ctrl_buf)->wTotalLength; // full length
  TU_ASSERT( usbh_control_xfer( new_addr, &request, _usbh_ctrl_buf ) );

  // update configuration info
  new_dev->interface_count = ((tusb_desc_configuration_t*) _usbh_ctrl_buf)->bNumInterfaces;

  //------------- Set Configure -------------//
  request = (tusb_control_request_t ) {
        .bmRequestType_bit = { .recipient = TUSB_REQ_RCPT_DEVICE, .type = TUSB_REQ_TYPE_STANDARD, .direction = TUSB_DIR_OUT },
        .bRequest = TUSB_REQ_SET_CONFIGURATION,
        .wValue = configure_selected,
        .wIndex = 0,
        .wLength = 0
  };
  TU_ASSERT(usbh_control_xfer( new_addr, &request, NULL ));

  new_dev->state = TUSB_DEVICE_STATE_CONFIGURED;

  //------------- TODO Get String Descriptors -------------//

  //------------- parse configuration & install drivers -------------//
  uint8_t const* p_desc = _usbh_ctrl_buf + sizeof(tusb_desc_configuration_t);

  // parse each interfaces
  while( p_desc < _usbh_ctrl_buf + ((tusb_desc_configuration_t*)_usbh_ctrl_buf)->wTotalLength )
  {
    // skip until we see interface descriptor
    if ( TUSB_DESC_INTERFACE != descriptor_type(p_desc) )
    {
      p_desc = descriptor_next(p_desc); // skip the descriptor, increase by the descriptor's length
    }else
    {
      tusb_desc_interface_t* desc_itf = (tusb_desc_interface_t*) p_desc;

      // Check if class is supported
      uint8_t drv_id;
      for (drv_id = 0; drv_id < USBH_CLASS_DRIVER_COUNT; drv_id++)
      {
        if ( usbh_class_drivers[drv_id].class_code == desc_itf->bInterfaceClass ) break;
      }
      
      if( drv_id >= USBH_CLASS_DRIVER_COUNT )
      {
        // skip unsupported class
        p_desc = descriptor_next(p_desc);
      }
      else
      {
        // Interface number must not be used already TODO alternate interface
        TU_ASSERT( new_dev->itf2drv[desc_itf->bInterfaceNumber] == 0xff );
        new_dev->itf2drv[desc_itf->bInterfaceNumber] = drv_id;

        if (desc_itf->bInterfaceClass == TUSB_CLASS_HUB && new_dev->hub_addr != 0)
        {
          // TODO Attach hub to Hub is not currently supported
          // skip this interface
          p_desc = descriptor_next(p_desc);
        }
        else
        {
          uint16_t itf_len = 0;

          if ( usbh_class_drivers[drv_id].open(new_dev->rhport, new_addr, desc_itf, &itf_len) )
          {
            mark_interface_endpoint(new_dev->ep2drv, p_desc, itf_len, drv_id);
          }

          TU_ASSERT( itf_len >= sizeof(tusb_desc_interface_t) );
          p_desc += itf_len;
        }
      }
    }
  }

  if (tuh_mount_cb) tuh_mount_cb(new_addr);

  return true;
}

bool usbh_task_body(void)
{
  while (1)
  {
    hcd_event_t event;
    if ( !osal_queue_receive(_usbh_q, &event) ) return false;

    switch (event.event_id)
    {
      case HCD_EVENT_DEVICE_ATTACH:
      case HCD_EVENT_DEVICE_REMOVE:
        enum_task(&event);
      break;

      default: break;
    }
  }
}

/* USB Host task
 * Thread that handles all device events. With an real RTOS, the task must be a forever loop and never return.
 * For coding convenience with no RTOS, we use wrapped sub-function for processing to easily return at any time.
 */
void usbh_task(void* param)
{
  (void) param;

#if CFG_TUSB_OS != OPT_OS_NONE
  while (1) {
#endif

  usbh_task_body();

#if CFG_TUSB_OS != OPT_OS_NONE
  }
#endif
}

//--------------------------------------------------------------------+
// INTERNAL HELPER
//--------------------------------------------------------------------+
static inline uint8_t get_new_address(void)
{
  uint8_t addr;
  for (addr=1; addr <= CFG_TUSB_HOST_DEVICE_MAX; addr++)
  {
    if (_usbh_devices[addr].state == TUSB_DEVICE_STATE_UNPLUG)
      break;
  }
  return addr;
}

static inline uint8_t get_configure_number_for_device(tusb_desc_device_t* dev_desc)
{
  uint8_t config_num = 1;

  // invoke callback to ask user which configuration to select
  if (tuh_device_attached_cb)
  {
    config_num = tu_min8(1, tuh_device_attached_cb(dev_desc) );
  }

  return config_num;
}

// Helper marking endpoint of interface belongs to class driver
// TODO merge with usbd
static void mark_interface_endpoint(uint8_t ep2drv[8][2], uint8_t const* p_desc, uint16_t desc_len, uint8_t driver_id)
{
  uint16_t len = 0;

  while( len < desc_len )
  {
    if ( TUSB_DESC_ENDPOINT == descriptor_type(p_desc) )
    {
      uint8_t const ep_addr = ((tusb_desc_endpoint_t const*) p_desc)->bEndpointAddress;

      ep2drv[ edpt_number(ep_addr) ][ edpt_dir(ep_addr) ] = driver_id;
    }

    len   += descriptor_len(p_desc);
    p_desc = descriptor_next(p_desc);
  }
}


#endif