diff --git a/src/class/cdc/cdc_device.c b/src/class/cdc/cdc_device.c
index 643706269..76526d40b 100644
--- a/src/class/cdc/cdc_device.c
+++ b/src/class/cdc/cdc_device.c
@@ -192,31 +192,31 @@ tusb_error_t cdcd_open(uint8_t rhport, tusb_desc_interface_t const * p_interface
   (*p_length) = sizeof(tusb_desc_interface_t);
 
   // Communication Functional Descriptors
-  while( TUSB_DESC_CLASS_SPECIFIC == p_desc[DESCRIPTOR_OFFSET_TYPE] )
+  while( TUSB_DESC_CLASS_SPECIFIC == p_desc[DESC_OFFSET_TYPE] )
   {
-    (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+    (*p_length) += p_desc[DESC_OFFSET_LEN];
     p_desc = descriptor_next(p_desc);
   }
 
-  if ( TUSB_DESC_ENDPOINT == p_desc[DESCRIPTOR_OFFSET_TYPE])
+  if ( TUSB_DESC_ENDPOINT == p_desc[DESC_OFFSET_TYPE])
   { // notification endpoint if any
     TU_ASSERT( dcd_edpt_open(rhport, (tusb_desc_endpoint_t const *) p_desc), TUSB_ERROR_DCD_OPEN_PIPE_FAILED);
 
     p_cdc->ep_notif = ((tusb_desc_endpoint_t const *) p_desc)->bEndpointAddress;
 
-    (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+    (*p_length) += p_desc[DESC_OFFSET_LEN];
     p_desc = descriptor_next(p_desc);
   }
 
   //------------- Data Interface (if any) -------------//
-  if ( (TUSB_DESC_INTERFACE == p_desc[DESCRIPTOR_OFFSET_TYPE]) &&
+  if ( (TUSB_DESC_INTERFACE == p_desc[DESC_OFFSET_TYPE]) &&
        (TUSB_CLASS_CDC_DATA == ((tusb_desc_interface_t const *) p_desc)->bInterfaceClass) )
   {
     // p_cdc->itf_num  =
     p_cdc->ep_count += ((tusb_desc_interface_t const *) p_desc)->bNumEndpoints;
 
     // next to endpoint descritpor
-    (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+    (*p_length) += p_desc[DESC_OFFSET_LEN];
     p_desc = descriptor_next(p_desc);
 
     // Open endpoint pair with usbd helper
diff --git a/src/class/cdc/cdc_host.c b/src/class/cdc/cdc_host.c
index bd5b5e32c..6950759d1 100644
--- a/src/class/cdc/cdc_host.c
+++ b/src/class/cdc/cdc_host.c
@@ -167,32 +167,32 @@ tusb_error_t cdch_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
   //------------- Communication Interface -------------//
   (*p_length) = sizeof(tusb_desc_interface_t);
 
-  while( TUSB_DESC_CLASS_SPECIFIC == p_desc[DESCRIPTOR_OFFSET_TYPE] )
+  while( TUSB_DESC_CLASS_SPECIFIC == p_desc[DESC_OFFSET_TYPE] )
   { // Communication Functional Descriptors
     if ( CDC_FUNC_DESC_ABSTRACT_CONTROL_MANAGEMENT == cdc_functional_desc_typeof(p_desc) )
     { // save ACM bmCapabilities
       p_cdc->acm_capability = ((cdc_desc_func_acm_t const *) p_desc)->bmCapabilities;
     }
 
-    (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+    (*p_length) += p_desc[DESC_OFFSET_LEN];
     p_desc = descriptor_next(p_desc);
   }
 
-  if ( TUSB_DESC_ENDPOINT == p_desc[DESCRIPTOR_OFFSET_TYPE])
+  if ( TUSB_DESC_ENDPOINT == p_desc[DESC_OFFSET_TYPE])
   { // notification endpoint if any
     p_cdc->pipe_notification = hcd_pipe_open(dev_addr, (tusb_desc_endpoint_t const *) p_desc, TUSB_CLASS_CDC);
 
-    (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+    (*p_length) += p_desc[DESC_OFFSET_LEN];
     p_desc = descriptor_next(p_desc);
 
     TU_ASSERT(pipehandle_is_valid(p_cdc->pipe_notification), TUSB_ERROR_HCD_OPEN_PIPE_FAILED);
   }
 
   //------------- Data Interface (if any) -------------//
-  if ( (TUSB_DESC_INTERFACE == p_desc[DESCRIPTOR_OFFSET_TYPE]) &&
+  if ( (TUSB_DESC_INTERFACE == p_desc[DESC_OFFSET_TYPE]) &&
        (TUSB_CLASS_CDC_DATA      == ((tusb_desc_interface_t const *) p_desc)->bInterfaceClass) )
   {
-    (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+    (*p_length) += p_desc[DESC_OFFSET_LEN];
     p_desc = descriptor_next(p_desc);
 
     // data endpoints expected to be in pairs
@@ -208,7 +208,7 @@ tusb_error_t cdch_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
       (*p_pipe_hdl) = hcd_pipe_open(dev_addr, p_endpoint, TUSB_CLASS_CDC);
       TU_ASSERT ( pipehandle_is_valid(*p_pipe_hdl), TUSB_ERROR_HCD_OPEN_PIPE_FAILED );
 
-      (*p_length) += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+      (*p_length) += p_desc[DESC_OFFSET_LEN];
       p_desc = descriptor_next( p_desc );
     }
   }
diff --git a/src/class/hid/hid_device.c b/src/class/hid/hid_device.c
index bc2ee8c64..9f22697a6 100644
--- a/src/class/hid/hid_device.c
+++ b/src/class/hid/hid_device.c
@@ -259,12 +259,12 @@ tusb_error_t hidd_open(uint8_t rhport, tusb_desc_interface_t const * p_interface
   uint8_t const *p_desc = (uint8_t const *) p_interface_desc;
 
   //------------- HID descriptor -------------//
-  p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+  p_desc += p_desc[DESC_OFFSET_LEN];
   tusb_hid_descriptor_hid_t const *p_desc_hid = (tusb_hid_descriptor_hid_t const *) p_desc;
   TU_ASSERT(HID_DESC_TYPE_HID == p_desc_hid->bDescriptorType, TUSB_ERROR_HIDD_DESCRIPTOR_INTERFACE);
 
   //------------- Endpoint Descriptor -------------//
-  p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+  p_desc += p_desc[DESC_OFFSET_LEN];
   tusb_desc_endpoint_t const *p_desc_endpoint = (tusb_desc_endpoint_t const *) p_desc;
   TU_ASSERT(TUSB_DESC_ENDPOINT == p_desc_endpoint->bDescriptorType, TUSB_ERROR_HIDD_DESCRIPTOR_INTERFACE);
 
diff --git a/src/class/hid/hid_host.c b/src/class/hid/hid_host.c
index 69f86ee0b..fe0b7748b 100644
--- a/src/class/hid/hid_host.c
+++ b/src/class/hid/hid_host.c
@@ -186,12 +186,12 @@ tusb_error_t hidh_open_subtask(uint8_t dev_addr, tusb_desc_interface_t const *p_
   uint8_t const *p_desc = (uint8_t const *) p_interface_desc;
 
   //------------- HID descriptor -------------//
-  p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+  p_desc += p_desc[DESC_OFFSET_LEN];
   tusb_hid_descriptor_hid_t const *p_desc_hid = (tusb_hid_descriptor_hid_t const *) p_desc;
   TU_ASSERT(HID_DESC_TYPE_HID == p_desc_hid->bDescriptorType, TUSB_ERROR_INVALID_PARA);
 
   //------------- Endpoint Descriptor -------------//
-  p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH];
+  p_desc += p_desc[DESC_OFFSET_LEN];
   tusb_desc_endpoint_t const * p_endpoint_desc = (tusb_desc_endpoint_t const *) p_desc;
   TU_ASSERT(TUSB_DESC_ENDPOINT == p_endpoint_desc->bDescriptorType, TUSB_ERROR_INVALID_PARA);
 
diff --git a/src/common/tusb_common.h b/src/common/tusb_common.h
index 2b45a50c9..ddfceabdb 100644
--- a/src/common/tusb_common.h
+++ b/src/common/tusb_common.h
@@ -144,12 +144,17 @@
 
 static inline uint8_t const * descriptor_next(uint8_t const p_desc[])
 {
-  return p_desc + p_desc[DESCRIPTOR_OFFSET_LENGTH];
+  return p_desc + p_desc[DESC_OFFSET_LEN];
 }
 
-static inline uint8_t descriptor_typeof(uint8_t const p_desc[])
+static inline uint8_t descriptor_type(uint8_t const p_desc[])
 {
-  return p_desc[DESCRIPTOR_OFFSET_TYPE];
+  return p_desc[DESC_OFFSET_TYPE];
+}
+
+static inline uint8_t descriptor_len(uint8_t const p_desc[])
+{
+  return p_desc[DESC_OFFSET_LEN];
 }
 
 //------------- Conversion -------------//
diff --git a/src/common/tusb_types.h b/src/common/tusb_types.h
index 4b8ef899c..65e7cd999 100644
--- a/src/common/tusb_types.h
+++ b/src/common/tusb_types.h
@@ -203,8 +203,8 @@ typedef enum
 }tusb_event_t;
 
 enum {
-  DESCRIPTOR_OFFSET_LENGTH = 0,
-  DESCRIPTOR_OFFSET_TYPE   = 1
+  DESC_OFFSET_LEN  = 0,
+  DESC_OFFSET_TYPE = 1
 };
 
 enum {
diff --git a/src/device/usbd.c b/src/device/usbd.c
index 504cdf77b..d795e4f9a 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -66,7 +66,10 @@ typedef struct {
   uint8_t config_num;
 
   // map interface number to driver (0xff is invalid)
-  uint8_t  itf2drv[16];
+  uint8_t itf2drv[16];
+
+  // map endpoint to driver ( 0xff is invalid )
+  uint8_t ep2drv[2][8];
 }usbd_device_t;
 
 CFG_TUSB_ATTR_USBRAM CFG_TUSB_MEM_ALIGN uint8_t _usbd_ctrl_buf[CFG_TUD_CTRL_BUFSIZE];
@@ -100,18 +103,6 @@ static usbd_class_driver_t const usbd_class_drivers[] =
     },
   #endif
 
-  #if DEVICE_CLASS_HID
-    {
-        .class_code     = TUSB_CLASS_HID,
-        .init           = hidd_init,
-        .open           = hidd_open,
-        .control_req_st = hidd_control_request_st,
-        .xfer_cb        = hidd_xfer_cb,
-        .sof            = NULL,
-        .reset          = hidd_reset
-    },
-  #endif
-
   #if CFG_TUD_MSC
     {
         .class_code     = TUSB_CLASS_MSC,
@@ -124,6 +115,19 @@ static usbd_class_driver_t const usbd_class_drivers[] =
     },
   #endif
 
+
+  #if DEVICE_CLASS_HID
+    {
+        .class_code     = TUSB_CLASS_HID,
+        .init           = hidd_init,
+        .open           = hidd_open,
+        .control_req_st = hidd_control_request_st,
+        .xfer_cb        = hidd_xfer_cb,
+        .sof            = NULL,
+        .reset          = hidd_reset
+    },
+  #endif
+
   #if CFG_TUD_CUSTOM_CLASS
     {
         .class_code     = TUSB_CLASS_VENDOR_SPECIFIC,
@@ -191,6 +195,7 @@ static osal_semaphore_def_t _usbd_sem_def;
 //--------------------------------------------------------------------+
 // INTERNAL FUNCTION
 //--------------------------------------------------------------------+
+static void mark_interface_endpoint(uint8_t const* p_desc, uint16_t desc_len, uint8_t driver_id);
 static tusb_error_t proc_set_config_req(uint8_t rhport, uint8_t config_number);
 static uint16_t get_descriptor(uint8_t rhport, tusb_control_request_t const * const p_request, uint8_t const ** pp_buffer);
 
@@ -300,6 +305,7 @@ static void usbd_reset(uint8_t rhport)
 {
   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
 
   for (uint8_t i = 0; i < USBD_CLASS_DRIVER_COUNT; i++)
   {
@@ -395,6 +401,7 @@ static tusb_error_t proc_control_request_st(uint8_t rhport, tusb_control_request
   OSAL_SUBTASK_END
 }
 
+// Process Set Configure Request
 // TODO Host (windows) can get HID report descriptor before set configured
 // may need to open interface before set configured
 static tusb_error_t proc_set_config_req(uint8_t rhport, uint8_t config_number)
@@ -418,33 +425,35 @@ static tusb_error_t proc_set_config_req(uint8_t rhport, uint8_t config_number)
 
   while( p_desc < desc_cfg + cfg_len )
   {
-    if ( TUSB_DESC_INTERFACE_ASSOCIATION == p_desc[DESCRIPTOR_OFFSET_TYPE])
+    if ( TUSB_DESC_INTERFACE_ASSOCIATION == descriptor_type(p_desc) )
     {
-      p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH]; // ignore Interface Association
+      p_desc = descriptor_next(p_desc); // ignore Interface Association
     }else
     {
-      TU_ASSERT( TUSB_DESC_INTERFACE == p_desc[DESCRIPTOR_OFFSET_TYPE], TUSB_ERROR_NOT_SUPPORTED_YET );
+      TU_ASSERT( TUSB_DESC_INTERFACE == descriptor_type(p_desc), TUSB_ERROR_NOT_SUPPORTED_YET );
 
       tusb_desc_interface_t* p_desc_itf = (tusb_desc_interface_t*) p_desc;
       uint8_t const class_code = p_desc_itf->bInterfaceClass;
 
       // Check if class is supported
-      uint8_t drid;
-      for (drid = 0; drid < USBD_CLASS_DRIVER_COUNT; drid++)
+      uint8_t drv_id;
+      for (drv_id = 0; drv_id < USBD_CLASS_DRIVER_COUNT; drv_id++)
       {
-        if ( usbd_class_drivers[drid].class_code == class_code ) break;
+        if ( usbd_class_drivers[drv_id].class_code == class_code ) break;
       }
-      TU_ASSERT( drid < USBD_CLASS_DRIVER_COUNT, TUSB_ERROR_NOT_SUPPORTED_YET );
+      TU_ASSERT( drv_id < USBD_CLASS_DRIVER_COUNT, TUSB_ERROR_NOT_SUPPORTED_YET );
 
       // Interface number must not be used
       TU_ASSERT( 0xff == _usbd_dev.itf2drv[p_desc_itf->bInterfaceNumber], TUSB_ERROR_FAILED);
-      _usbd_dev.itf2drv[p_desc_itf->bInterfaceNumber] = drid;
+      _usbd_dev.itf2drv[p_desc_itf->bInterfaceNumber] = drv_id;
 
-      uint16_t length=0;
-      TU_ASSERT_ERR( usbd_class_drivers[drid].open( rhport, p_desc_itf, &length ) );
+      uint16_t len=0;
+      TU_ASSERT_ERR( usbd_class_drivers[drv_id].open( rhport, p_desc_itf, &len ) );
+      TU_ASSERT( len >= sizeof(tusb_desc_interface_t), TUSB_ERROR_FAILED );
 
-      TU_ASSERT( length >= sizeof(tusb_desc_interface_t), TUSB_ERROR_FAILED );
-      p_desc += length;
+      mark_interface_endpoint(p_desc, len, drv_id);
+
+      p_desc += len; // next interface
     }
   }
 
@@ -454,6 +463,7 @@ static tusb_error_t proc_set_config_req(uint8_t rhport, uint8_t config_number)
   return TUSB_ERROR_NONE;
 }
 
+// return len of descriptor and change pointer to descriptor's buffer
 static uint16_t get_descriptor(uint8_t rhport, tusb_control_request_t const * const p_request, uint8_t const ** pp_buffer)
 {
   (void) rhport;
@@ -514,6 +524,25 @@ static uint16_t get_descriptor(uint8_t rhport, tusb_control_request_t const * co
   return len;
 }
 
+// Helper marking endpoint of interface belongs to class driver
+static void mark_interface_endpoint(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;
+
+      _usbd_dev.ep2drv[ edpt_dir(ep_addr) ][ edpt_number(ep_addr) ] = driver_id;
+    }
+
+    len   += descriptor_len(p_desc);
+    p_desc = descriptor_next(p_desc);
+  }
+}
+
 //--------------------------------------------------------------------+
 // USBD-DCD Callback API
 //--------------------------------------------------------------------+
diff --git a/src/host/usbh.c b/src/host/usbh.c
index a67bd8d8c..6d1cd37ad 100644
--- a/src/host/usbh.c
+++ b/src/host/usbh.c
@@ -572,9 +572,9 @@ tusb_error_t enumeration_body_subtask(void)
   while( p_desc < enum_data_buffer + ((tusb_desc_configuration_t*)enum_data_buffer)->wTotalLength )
   {
     // skip until we see interface descriptor
-    if ( TUSB_DESC_INTERFACE != p_desc[DESCRIPTOR_OFFSET_TYPE] )
+    if ( TUSB_DESC_INTERFACE != p_desc[DESC_OFFSET_TYPE] )
     {
-      p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH]; // skip the descriptor, increase by the descriptor's length
+      p_desc += p_desc[DESC_OFFSET_LEN]; // skip the descriptor, increase by the descriptor's length
     }else
     {
       static uint8_t class_index; // has to be static as it is used to call class's open_subtask
@@ -600,11 +600,11 @@ tusb_error_t enumeration_body_subtask(void)
           p_desc += length;
         }else  // Interface open failed, for example a subclass is not supported
         {
-          p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH]; // skip this interface, the rest will be skipped by the above loop
+          p_desc += p_desc[DESC_OFFSET_LEN]; // skip this interface, the rest will be skipped by the above loop
         }
       } else // unsupported class (not enable or yet implemented)
       {
-        p_desc += p_desc[DESCRIPTOR_OFFSET_LENGTH]; // skip this interface, the rest will be skipped by the above loop
+        p_desc += p_desc[DESC_OFFSET_LEN]; // skip this interface, the rest will be skipped by the above loop
       }
     }
   }