src/device/usbd.c

/* 
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * 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.
 *
 * This file is part of the TinyUSB stack.
 */

#include "tusb_option.h"

#if TUSB_OPT_DEVICE_ENABLED

#include "tusb.h"
#include "usbd.h"
#include "device/usbd_pvt.h"
#include "dcd.h"

#ifndef CFG_TUD_TASK_QUEUE_SZ
#define CFG_TUD_TASK_QUEUE_SZ   16
#endif

//--------------------------------------------------------------------+
// Device Data
//--------------------------------------------------------------------+
typedef struct {
  struct TU_ATTR_PACKED
  {
      volatile uint8_t connected    : 1;
      volatile uint8_t configured   : 1;
      volatile uint8_t suspended    : 1;

      uint8_t remote_wakeup_en      : 1; // enable/disable by host
      uint8_t remote_wakeup_support : 1; // configuration descriptor's attribute
      uint8_t self_powered          : 1; // configuration descriptor's attribute
  };

  uint8_t ep_busy_map[2];  // bit mask for busy endpoint
  uint8_t ep_stall_map[2]; // bit map for stalled endpoint

  uint8_t itf2drv[16];      // map interface number to driver (0xff is invalid)
  uint8_t ep2drv[8][2];     // map endpoint to driver ( 0xff is invalid )
}usbd_device_t;

static usbd_device_t _usbd_dev = { 0 };

//--------------------------------------------------------------------+
// Class Driver
//--------------------------------------------------------------------+
typedef struct {
  uint8_t class_code;

  void (* init           ) (void);
  bool (* open           ) (uint8_t rhport, tusb_desc_interface_t const * desc_intf, uint16_t* p_length);
  bool (* control_request ) (uint8_t rhport, tusb_control_request_t const * request);
  bool (* control_request_complete ) (uint8_t rhport, tusb_control_request_t const * request);
  bool (* xfer_cb        ) (uint8_t rhport, uint8_t ep_addr, xfer_result_t, uint32_t);
  void (* sof            ) (uint8_t rhport);
  void (* reset          ) (uint8_t);
} usbd_class_driver_t;

static usbd_class_driver_t const usbd_class_drivers[] =
{
  #if CFG_TUD_CDC
    {
        .class_code      = TUSB_CLASS_CDC,
        .init            = cdcd_init,
        .open            = cdcd_open,
        .control_request = cdcd_control_request,
        .control_request_complete = cdcd_control_request_complete,
        .xfer_cb         = cdcd_xfer_cb,
        .sof             = NULL,
        .reset           = cdcd_reset
    },
  #endif

  #if CFG_TUD_MSC
    {
        .class_code      = TUSB_CLASS_MSC,
        .init            = mscd_init,
        .open            = mscd_open,
        .control_request = mscd_control_request,
        .control_request_complete = mscd_control_request_complete,
        .xfer_cb         = mscd_xfer_cb,
        .sof             = NULL,
        .reset           = mscd_reset
    },
  #endif

  #if CFG_TUD_HID
    {
        .class_code      = TUSB_CLASS_HID,
        .init            = hidd_init,
        .open            = hidd_open,
        .control_request = hidd_control_request,
        .control_request_complete = hidd_control_request_complete,
        .xfer_cb         = hidd_xfer_cb,
        .sof             = NULL,
        .reset           = hidd_reset
    },
  #endif

  #if CFG_TUD_MIDI
    {
        .class_code      = TUSB_CLASS_AUDIO,
        .init            = midid_init,
        .open            = midid_open,
        .control_request = midid_control_request,
        .control_request_complete = midid_control_request_complete,
        .xfer_cb         = midid_xfer_cb,
        .sof             = NULL,
        .reset           = midid_reset
    },
  #endif

  #if CFG_TUD_CUSTOM_CLASS
    {
        .class_code      = TUSB_CLASS_VENDOR_SPECIFIC,
        .init            = cusd_init,
        .open            = cusd_open,
        .control_request = cusd_control_request,
        .control_request_complete = cusd_control_request_complete,
        .xfer_cb         = cusd_xfer_cb,
        .sof             = NULL,
        .reset           = cusd_reset
    },
  #endif
};

enum { USBD_CLASS_DRIVER_COUNT = TU_ARRAY_SZIE(usbd_class_drivers) };

//--------------------------------------------------------------------+
// DCD Event
//--------------------------------------------------------------------+

// Event queue
// OPT_MODE_DEVICE is used by OS NONE for mutex (disable usb isr)
OSAL_QUEUE_DEF(OPT_MODE_DEVICE, _usbd_qdef, CFG_TUD_TASK_QUEUE_SZ, dcd_event_t);
static osal_queue_t _usbd_q;

//--------------------------------------------------------------------+
// Prototypes
//--------------------------------------------------------------------+
static void mark_interface_endpoint(uint8_t ep2drv[8][2], uint8_t const* p_desc, uint16_t desc_len, uint8_t driver_id);
static bool process_control_request(uint8_t rhport, tusb_control_request_t const * p_request);
static bool process_set_config(uint8_t rhport, uint8_t cfg_num);
static bool process_get_descriptor(uint8_t rhport, tusb_control_request_t const * p_request);

void usbd_control_reset (uint8_t rhport);
bool usbd_control_xfer_cb (uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
void usbd_control_set_complete_callback( bool (*fp) (uint8_t, tusb_control_request_t const * ) );

//--------------------------------------------------------------------+
// Application API
//--------------------------------------------------------------------+
bool tud_mounted(void)
{
  return _usbd_dev.configured;
}

bool tud_suspended(void)
{
  return _usbd_dev.suspended;
}

bool tud_remote_wakeup(void)
{
  // only wake up host if this feature is supported and enabled and we are suspended
  TU_VERIFY (_usbd_dev.suspended && _usbd_dev.remote_wakeup_support && _usbd_dev.remote_wakeup_en );
  dcd_remote_wakeup(TUD_OPT_RHPORT);
  return true;
}

//--------------------------------------------------------------------+
// USBD Task
//--------------------------------------------------------------------+
bool usbd_init (void)
{
  tu_varclr(&_usbd_dev);

  // Init device queue & task
  _usbd_q = osal_queue_create(&_usbd_qdef);
  TU_ASSERT(_usbd_q != NULL);

  // Init class drivers
  for (uint8_t i = 0; i < USBD_CLASS_DRIVER_COUNT; i++) usbd_class_drivers[i].init();

  // Init device controller driver
  dcd_init(TUD_OPT_RHPORT);
  dcd_int_enable(TUD_OPT_RHPORT);

  return true;
}

static void usbd_reset(uint8_t rhport)
{
  tu_varclr(&_usbd_dev);

  memset(_usbd_dev.itf2drv, 0xff, sizeof(_usbd_dev.itf2drv)); // invalid mapping
  memset(_usbd_dev.ep2drv , 0xff, sizeof(_usbd_dev.ep2drv )); // invalid mapping

  usbd_control_reset(rhport);

  for (uint8_t i = 0; i < USBD_CLASS_DRIVER_COUNT; i++)
  {
    if ( usbd_class_drivers[i].reset ) usbd_class_drivers[i].reset( rhport );
  }
}

/* USB Device Driver task
 * This top level thread manages all device controller event and delegates events to class-specific drivers.
 * This should be called periodically within the mainloop or rtos thread.
 *
   @code
    int main(void)
    {
      application_init();
      tusb_init();

      while(1) // the mainloop
      {
        application_code();

        tud_task(); // tinyusb device task
      }
    }
    @endcode
 */
void tud_task (void)
{
  // Skip if stack is not initialized
  if ( !tusb_inited() ) return;

  // Loop until there is no more events in the queue
  while (1)
  {
    dcd_event_t event;

    if ( !osal_queue_receive(_usbd_q, &event) ) return;

    switch ( event.event_id )
    {
      case DCD_EVENT_BUS_RESET:
        usbd_reset(event.rhport);
      break;

      case DCD_EVENT_UNPLUGGED:
        usbd_reset(event.rhport);

        // invoke callback
        if (tud_umount_cb) tud_umount_cb();
      break;

      case DCD_EVENT_SETUP_RECEIVED:
        // Mark as connected after receiving 1st setup packet.
        // But it is easier to set it every time instead of wasting time to check then set
        _usbd_dev.connected = 1;

        // Process control request
        if ( !process_control_request(event.rhport, &event.setup_received) )
        {
          // Failed -> stall both control endpoint IN and OUT
          dcd_edpt_stall(event.rhport, 0);
          dcd_edpt_stall(event.rhport, 0 | TUSB_DIR_IN_MASK);
        }
      break;

      case DCD_EVENT_XFER_COMPLETE:
        // Only handle xfer callback in ready state
        // if (_usbd_dev.connected && !_usbd_dev.suspended)
        {
          // Invoke the class callback associated with the endpoint address
          uint8_t const ep_addr = event.xfer_complete.ep_addr;
          uint8_t const epnum = tu_edpt_number(ep_addr);
          uint8_t const dir   = tu_edpt_dir(ep_addr);

          _usbd_dev.ep_busy_map[dir] = (uint8_t) tu_bit_clear(_usbd_dev.ep_busy_map[dir], epnum);

          if ( 0 == tu_edpt_number(ep_addr) )
          {
            // control transfer DATA stage callback
            usbd_control_xfer_cb(event.rhport, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
          }
          else
          {
            uint8_t const drv_id = _usbd_dev.ep2drv[tu_edpt_number(ep_addr)][tu_edpt_dir(ep_addr)];
            TU_ASSERT(drv_id < USBD_CLASS_DRIVER_COUNT,);

            usbd_class_drivers[drv_id].xfer_cb(event.rhport, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
          }
        }
      break;

      case DCD_EVENT_SUSPEND:
        if (tud_suspend_cb) tud_suspend_cb(_usbd_dev.remote_wakeup_en);
      break;

      case DCD_EVENT_RESUME:
        if (tud_resume_cb) tud_resume_cb();
      break;

      case DCD_EVENT_SOF:
        for ( uint8_t i = 0; i < USBD_CLASS_DRIVER_COUNT; i++ )
        {
          if ( usbd_class_drivers[i].sof )
          {
            usbd_class_drivers[i].sof(event.rhport);
          }
        }
      break;

      case USBD_EVENT_FUNC_CALL:
        if ( event.func_call.func ) event.func_call.func(event.func_call.param);
      break;

      default:
        TU_BREAKPOINT();
      break;
    }
  }
}

//--------------------------------------------------------------------+
// Control Request Parser & Handling
//--------------------------------------------------------------------+

// This handles the actual request and its response.
// return false will cause its caller to stall control endpoint
static bool process_control_request(uint8_t rhport, tusb_control_request_t const * p_request)
{
  usbd_control_set_complete_callback(NULL);

  switch ( p_request->bmRequestType_bit.recipient )
  {
    //------------- Device Requests e.g in enumeration -------------//
    case TUSB_REQ_RCPT_DEVICE:
      if ( TUSB_REQ_TYPE_STANDARD != p_request->bmRequestType_bit.type )
      {
        // Non standard request is not supported
        TU_BREAKPOINT();
        return false;
      }

      switch ( p_request->bRequest )
      {
        case TUSB_REQ_SET_ADDRESS:
          // Depending on mcu, status phase could be sent either before or after changing device address
          // Therefore DCD must include zero-length status response
          dcd_set_address(rhport, (uint8_t) p_request->wValue);
          return true; // skip status
        break;

        case TUSB_REQ_GET_CONFIGURATION:
        {
          uint8_t cfgnum = _usbd_dev.configured ? 1 : 0;
          usbd_control_xfer(rhport, p_request, &cfgnum, 1);
        }
        break;

        case TUSB_REQ_SET_CONFIGURATION:
        {
          uint8_t const cfg_num = (uint8_t) p_request->wValue;

          dcd_set_config(rhport, cfg_num);
          _usbd_dev.configured = cfg_num ? 1 : 0;

          if ( cfg_num ) TU_ASSERT( process_set_config(rhport, cfg_num) );
          usbd_control_status(rhport, p_request);
        }
        break;

        case TUSB_REQ_GET_DESCRIPTOR:
          TU_VERIFY( process_get_descriptor(rhport, p_request) );
        break;

        case TUSB_REQ_SET_FEATURE:
          // Only support remote wakeup for device feature
          TU_VERIFY(TUSB_REQ_FEATURE_REMOTE_WAKEUP == p_request->wValue);

          // Host may enable remote wake up before suspending especially HID device
          _usbd_dev.remote_wakeup_en = true;
          usbd_control_status(rhport, p_request);
        break;

        case TUSB_REQ_CLEAR_FEATURE:
          // Only support remote wakeup for device feature
          TU_VERIFY(TUSB_REQ_FEATURE_REMOTE_WAKEUP == p_request->wValue);

          // Host may disable remote wake up after resuming
          _usbd_dev.remote_wakeup_en = false;
          usbd_control_status(rhport, p_request);
        break;

        case TUSB_REQ_GET_STATUS:
        {
          // Device status bit mask
          // - Bit 0: Self Powered
          // - Bit 1: Remote Wakeup enabled
          uint16_t status = (_usbd_dev.self_powered ? 1 : 0) | (_usbd_dev.remote_wakeup_en ? 2 : 0);
          usbd_control_xfer(rhport, p_request, &status, 2);
        }
        break;

        // Unknown/Unsupported request
        default: TU_BREAKPOINT(); return false;
      }
    break;

    //------------- Class/Interface Specific Request -------------//
    case TUSB_REQ_RCPT_INTERFACE:
    {
      uint8_t const itf = tu_u16_low(p_request->wIndex);
      uint8_t const drvid = _usbd_dev.itf2drv[itf];

      TU_VERIFY(drvid < USBD_CLASS_DRIVER_COUNT);

      usbd_control_set_complete_callback(usbd_class_drivers[drvid].control_request_complete );

      // stall control endpoint if driver return false
      return usbd_class_drivers[drvid].control_request(rhport, p_request);
    }
    break;

    //------------- Endpoint Request -------------//
    case TUSB_REQ_RCPT_ENDPOINT:
      // Non standard request is not supported
      TU_VERIFY( TUSB_REQ_TYPE_STANDARD == p_request->bmRequestType_bit.type );

      switch ( p_request->bRequest )
      {
        case TUSB_REQ_GET_STATUS:
        {
          uint16_t status = usbd_edpt_stalled(rhport, tu_u16_low(p_request->wIndex)) ? 0x0001 : 0x0000;
          usbd_control_xfer(rhport, p_request, &status, 2);
        }
        break;

        case TUSB_REQ_CLEAR_FEATURE:
          if ( TUSB_REQ_FEATURE_EDPT_HALT == p_request->wValue )
          {
            usbd_edpt_clear_stall(rhport, tu_u16_low(p_request->wIndex));
          }
          usbd_control_status(rhport, p_request);
        break;

        case TUSB_REQ_SET_FEATURE:
          if ( TUSB_REQ_FEATURE_EDPT_HALT == p_request->wValue )
          {
            usbd_edpt_stall(rhport, tu_u16_low(p_request->wIndex));
          }
          usbd_control_status(rhport, p_request);
        break;

        // Unknown/Unsupported request
        default: TU_BREAKPOINT(); return false;
      }
    break;

    // Unknown recipient
    default: TU_BREAKPOINT(); return false;
  }

  return true;
}

// Process Set Configure Request
// This function parse configuration descriptor & open drivers accordingly
static bool process_set_config(uint8_t rhport, uint8_t cfg_num)
{
  tusb_desc_configuration_t const * desc_cfg = (tusb_desc_configuration_t const *) tud_descriptor_configuration_cb(cfg_num-1); // index is cfg_num-1
  TU_ASSERT(desc_cfg != NULL && desc_cfg->bDescriptorType == TUSB_DESC_CONFIGURATION);

  // Parse configuration descriptor
  _usbd_dev.remote_wakeup_support = (desc_cfg->bmAttributes & TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP) ? 1 : 0;
  _usbd_dev.self_powered = (desc_cfg->bmAttributes & TUSB_DESC_CONFIG_ATT_SELF_POWERED) ? 1 : 0;

  // Parse interface descriptor
  uint8_t const * p_desc   = ((uint8_t const*) desc_cfg) + sizeof(tusb_desc_configuration_t);
  uint8_t const * desc_end = ((uint8_t const*) desc_cfg) + desc_cfg->wTotalLength;

  while( p_desc < desc_end )
  {
    // Each interface always starts with Interface or Association descriptor
    if ( TUSB_DESC_INTERFACE_ASSOCIATION == tu_desc_type(p_desc) )
    {
      p_desc = tu_desc_next(p_desc); // ignore Interface Association
    }else
    {
      TU_ASSERT( TUSB_DESC_INTERFACE == tu_desc_type(p_desc) );

      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 < USBD_CLASS_DRIVER_COUNT; drv_id++)
      {
        if ( usbd_class_drivers[drv_id].class_code == desc_itf->bInterfaceClass ) break;
      }
      TU_ASSERT( drv_id < USBD_CLASS_DRIVER_COUNT );

      // Interface number must not be used already TODO alternate interface
      TU_ASSERT( 0xff == _usbd_dev.itf2drv[desc_itf->bInterfaceNumber] );
      _usbd_dev.itf2drv[desc_itf->bInterfaceNumber] = drv_id;

      uint16_t itf_len=0;
      TU_ASSERT( usbd_class_drivers[drv_id].open( rhport, desc_itf, &itf_len ) );
      TU_ASSERT( itf_len >= sizeof(tusb_desc_interface_t) );

      mark_interface_endpoint(_usbd_dev.ep2drv, p_desc, itf_len, drv_id);

      p_desc += itf_len; // next interface
    }
  }

  // invoke callback
  if (tud_mount_cb) tud_mount_cb();

  return true;
}

// Helper marking endpoint of interface belongs to class driver
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 == tu_desc_type(p_desc) )
    {
      uint8_t const ep_addr = ((tusb_desc_endpoint_t const*) p_desc)->bEndpointAddress;

      ep2drv[tu_edpt_number(ep_addr)][tu_edpt_dir(ep_addr)] = driver_id;
    }

    len   += tu_desc_len(p_desc);
    p_desc = tu_desc_next(p_desc);
  }
}

// return descriptor's buffer and update desc_len
static bool process_get_descriptor(uint8_t rhport, tusb_control_request_t const * p_request)
{
  tusb_desc_type_t const desc_type = (tusb_desc_type_t) tu_u16_high(p_request->wValue);
  uint8_t const desc_index = tu_u16_low( p_request->wValue );

  switch(desc_type)
  {
    case TUSB_DESC_DEVICE:
      return usbd_control_xfer(rhport, p_request, (void*) tud_descriptor_device_cb(), sizeof(tusb_desc_device_t));
    break;

    case TUSB_DESC_CONFIGURATION:
    {
      tusb_desc_configuration_t const* desc_config = (tusb_desc_configuration_t const*) tud_descriptor_configuration_cb(desc_index);
      return usbd_control_xfer(rhport, p_request, (void*) desc_config, desc_config->wTotalLength);
    }
    break;

    case TUSB_DESC_STRING:
      // String Descriptor always uses the desc set from user
      if ( desc_index == 0xEE )
      {
        // The 0xEE index string is a Microsoft USB extension.
        // It can be used to tell Windows what driver it should use for the device !!!
        return false;
      }else
      {
        uint8_t const* desc_str = (uint8_t const*) tud_descriptor_string_cb(desc_index);
        TU_ASSERT(desc_str);

        // first byte of descriptor is its size
        return usbd_control_xfer(rhport, p_request, (void*) desc_str, desc_str[0]);
      }
    break;

    case TUSB_DESC_DEVICE_QUALIFIER:
      // TODO If not highspeed capable stall this request otherwise
      // return the descriptor that could work in highspeed
      return false;
    break;

    default: return false;
  }

  return true;
}

//--------------------------------------------------------------------+
// DCD Event Handler
//--------------------------------------------------------------------+
void dcd_event_handler(dcd_event_t const * event, bool in_isr)
{
  switch (event->event_id)
  {
    case DCD_EVENT_BUS_RESET:
      osal_queue_send(_usbd_q, event, in_isr);
    break;

    case DCD_EVENT_UNPLUGGED:
      _usbd_dev.connected = 0;
      _usbd_dev.configured = 0;
      _usbd_dev.suspended = 0;
      osal_queue_send(_usbd_q, event, in_isr);
    break;

    case DCD_EVENT_SOF:
      // nothing to do now
    break;

    case DCD_EVENT_SUSPEND:
      // NOTE: When plugging/unplugging device, the D+/D- state are unstable and can accidentally meet the
      // SUSPEND condition ( Idle for 3ms ). Some MCUs such as SAMD doesn't distinguish suspend vs disconnect as well.
      // We will skip handling SUSPEND/RESUME event if not currently connected
      if ( _usbd_dev.connected )
      {
        _usbd_dev.suspended = 1;
        osal_queue_send(_usbd_q, event, in_isr);
      }
    break;

    case DCD_EVENT_RESUME:
      if ( _usbd_dev.connected )
      {
        _usbd_dev.suspended = 0;
        osal_queue_send(_usbd_q, event, in_isr);
      }
    break;

    case DCD_EVENT_SETUP_RECEIVED:
      osal_queue_send(_usbd_q, event, in_isr);
    break;

    case DCD_EVENT_XFER_COMPLETE:
      // skip zero-length control status complete event, should DCD notify us.
      // TODO could cause issue with actual zero length data used by class such as DFU
      if ( (0 == tu_edpt_number(event->xfer_complete.ep_addr)) && (event->xfer_complete.len == 0) ) break;

      osal_queue_send(_usbd_q, event, in_isr);
      TU_ASSERT(event->xfer_complete.result == XFER_RESULT_SUCCESS,);
    break;

    // Not an DCD event, just a convenient way to defer ISR function should we need to
    case USBD_EVENT_FUNC_CALL:
      osal_queue_send(_usbd_q, event, in_isr);
    break;

    default: break;
  }
}

// helper to send bus signal event
void dcd_event_bus_signal (uint8_t rhport, dcd_eventid_t eid, bool in_isr)
{
  dcd_event_t event = { .rhport = rhport, .event_id = eid, };
  dcd_event_handler(&event, in_isr);
}

// helper to send setup received
void dcd_event_setup_received(uint8_t rhport, uint8_t const * setup, bool in_isr)
{
  dcd_event_t event = { .rhport = rhport, .event_id = DCD_EVENT_SETUP_RECEIVED };
  memcpy(&event.setup_received, setup, 8);

  dcd_event_handler(&event, in_isr);
}

// helper to send transfer complete event
void dcd_event_xfer_complete (uint8_t rhport, uint8_t ep_addr, uint32_t xferred_bytes, uint8_t result, bool in_isr)
{
  dcd_event_t event = { .rhport = rhport, .event_id = DCD_EVENT_XFER_COMPLETE };

  event.xfer_complete.ep_addr = ep_addr;
  event.xfer_complete.len     = xferred_bytes;
  event.xfer_complete.result  = result;

  dcd_event_handler(&event, in_isr);
}

//--------------------------------------------------------------------+
// Helper
//--------------------------------------------------------------------+

// Parse consecutive endpoint descriptors (IN & OUT)
bool usbd_open_edpt_pair(uint8_t rhport, uint8_t const* p_desc, uint8_t ep_count, uint8_t xfer_type, uint8_t* ep_out, uint8_t* ep_in)
{
  for(int i=0; i<ep_count; i++)
  {
    tusb_desc_endpoint_t const * desc_ep = (tusb_desc_endpoint_t const *) p_desc;

    TU_VERIFY(TUSB_DESC_ENDPOINT == desc_ep->bDescriptorType && xfer_type == desc_ep->bmAttributes.xfer);
    TU_ASSERT(dcd_edpt_open(rhport, desc_ep));

    if ( tu_edpt_dir(desc_ep->bEndpointAddress) == TUSB_DIR_IN )
    {
      (*ep_in) = desc_ep->bEndpointAddress;
    }else
    {
      (*ep_out) = desc_ep->bEndpointAddress;
    }

    p_desc = tu_desc_next(p_desc);
  }

  return true;
}

// Helper to defer an isr function
void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr)
{
  dcd_event_t event =
  {
      .rhport   = 0,
      .event_id = USBD_EVENT_FUNC_CALL,
  };

  event.func_call.func  = func;
  event.func_call.param = param;

  dcd_event_handler(&event, in_isr);
}

//--------------------------------------------------------------------+
// USBD Endpoint API
//--------------------------------------------------------------------+

bool usbd_edpt_xfer(uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes)
{
  uint8_t const epnum = tu_edpt_number(ep_addr);
  uint8_t const dir   = tu_edpt_dir(ep_addr);

  TU_VERIFY( dcd_edpt_xfer(rhport, ep_addr, buffer, total_bytes) );

  _usbd_dev.ep_busy_map[dir] = (uint8_t) tu_bit_set(_usbd_dev.ep_busy_map[dir], epnum);

  return true;
}

bool usbd_edpt_busy(uint8_t rhport, uint8_t ep_addr)
{
  (void) rhport;

  uint8_t const epnum = tu_edpt_number(ep_addr);
  uint8_t const dir   = tu_edpt_dir(ep_addr);

  return tu_bit_test(_usbd_dev.ep_busy_map[dir], epnum);
}


void usbd_edpt_stall(uint8_t rhport, uint8_t ep_addr)
{
  uint8_t const epnum = tu_edpt_number(ep_addr);
  uint8_t const dir   = tu_edpt_dir(ep_addr);

  dcd_edpt_stall(rhport, ep_addr);
  _usbd_dev.ep_stall_map[dir] = (uint8_t) tu_bit_set(_usbd_dev.ep_stall_map[dir], epnum);
}

void usbd_edpt_clear_stall(uint8_t rhport, uint8_t ep_addr)
{
  uint8_t const epnum = tu_edpt_number(ep_addr);
  uint8_t const dir   = tu_edpt_dir(ep_addr);

  dcd_edpt_clear_stall(rhport, ep_addr);
  _usbd_dev.ep_stall_map[dir] = (uint8_t) tu_bit_clear(_usbd_dev.ep_stall_map[dir], epnum);
}

bool usbd_edpt_stalled(uint8_t rhport, uint8_t ep_addr)
{
  (void) rhport;

  uint8_t const epnum = tu_edpt_number(ep_addr);
  uint8_t const dir   = tu_edpt_dir(ep_addr);

  return tu_bit_test(_usbd_dev.ep_stall_map[dir], epnum);
}

#endif