Merge branch 'master' into vendor_class_zero_length_transfer

8 files changed, 2123 insertions, 1116 deletions

diff --git a/src/host/hcd.h b/src/host/hcd.h
index 46209dc45..5547c7cc5 100644
--- a/src/host/hcd.h
+++ b/src/host/hcd.h
@@ -1,4 +1,4 @@
-/* 
+/*
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
@@ -35,7 +35,22 @@
  extern "C" {
 #endif
 
- //--------------------------------------------------------------------+
+//--------------------------------------------------------------------+
+// Configuration
+//--------------------------------------------------------------------+
+
+// Max number of endpoints pair per device
+// TODO optimize memory usage
+#ifndef CFG_TUH_ENDPOINT_MAX
+  #define CFG_TUH_ENDPOINT_MAX   16
+//  #ifdef TUP_HCD_ENDPOINT_MAX
+//    #define CFG_TUH_ENDPPOINT_MAX   TUP_HCD_ENDPOINT_MAX
+//  #else
+//    #define
+//  #endif
+#endif
+
+//--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
 typedef enum
@@ -62,6 +77,7 @@ typedef struct
     struct {
       uint8_t hub_addr;
       uint8_t hub_port;
+      uint8_t speed;
     } connection;
 
     // XFER_COMPLETE
@@ -80,27 +96,45 @@ typedef struct
 
 } hcd_event_t;
 
-#if TUSB_OPT_HOST_ENABLED
-// Max number of endpoints per device
-enum {
-  // TODO better computation
-  HCD_MAX_ENDPOINT = CFG_TUSB_HOST_DEVICE_MAX*(CFG_TUH_HUB + CFG_TUH_HID*2 + CFG_TUH_MSC*2 + CFG_TUH_CDC*3),
-  HCD_MAX_XFER     = HCD_MAX_ENDPOINT*2,
-};
+typedef struct
+{
+  uint8_t rhport;
+  uint8_t hub_addr;
+  uint8_t hub_port;
+  uint8_t speed;
+} hcd_devtree_info_t;
 
-//#define HCD_MAX_ENDPOINT 16
-//#define HCD_MAX_XFER 16
-#endif
+//--------------------------------------------------------------------+
+// Memory API
+//--------------------------------------------------------------------+
+
+// clean/flush data cache: write cache -> memory.
+// Required before an DMA TX transfer to make sure data is in memory
+bool hcd_dcache_clean(void const* addr, uint32_t data_size) TU_ATTR_WEAK;
+
+// invalidate data cache: mark cache as invalid, next read will read from memory
+// Required BOTH before and after an DMA RX transfer
+bool hcd_dcache_invalidate(void const* addr, uint32_t data_size) TU_ATTR_WEAK;
+
+// clean and invalidate data cache
+// Required before an DMA transfer where memory is both read/write by DMA
+bool hcd_dcache_clean_invalidate(void const* addr, uint32_t data_size) TU_ATTR_WEAK;
 
 //--------------------------------------------------------------------+
 // Controller API
 //--------------------------------------------------------------------+
 
+// optional hcd configuration, called by tuh_configure()
+bool hcd_configure(uint8_t rhport, uint32_t cfg_id, const void* cfg_param);
+
 // Initialize controller to host mode
 bool hcd_init(uint8_t rhport);
 
+// De-initialize controller
+bool hcd_deinit(uint8_t rhport);
+
 // Interrupt Handler
-void hcd_int_handler(uint8_t rhport);
+void hcd_int_handler(uint8_t rhport, bool in_isr);
 
 // Enable USB interrupt
 void hcd_int_enable (uint8_t rhport);
@@ -118,10 +152,11 @@ uint32_t hcd_frame_number(uint8_t rhport);
 // Get the current connect status of roothub port
 bool hcd_port_connect_status(uint8_t rhport);
 
-// Reset USB bus on the port
+// Reset USB bus on the port. Return immediately, bus reset sequence may not be complete.
+// Some port would require hcd_port_reset_end() to be invoked after 10ms to complete the reset sequence.
 void hcd_port_reset(uint8_t rhport);
 
-// TODO implement later
+// Complete bus reset sequence, may be required by some controllers
 void hcd_port_reset_end(uint8_t rhport);
 
 // Get port link speed
@@ -134,29 +169,74 @@ void hcd_device_close(uint8_t rhport, uint8_t dev_addr);
 // Endpoints API
 //--------------------------------------------------------------------+
 
-bool hcd_setup_send(uint8_t rhport, uint8_t dev_addr, uint8_t const setup_packet[8]);
-bool hcd_edpt_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_endpoint_t const * ep_desc);
-bool hcd_edpt_xfer(uint8_t rhport, uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t buflen);
+// Open an endpoint
+bool hcd_edpt_open(uint8_t rhport, uint8_t daddr, tusb_desc_endpoint_t const * ep_desc);
+
+// Submit a transfer, when complete hcd_event_xfer_complete() must be invoked
+bool hcd_edpt_xfer(uint8_t rhport, uint8_t daddr, uint8_t ep_addr, uint8_t * buffer, uint16_t buflen);
+
+// Abort a queued transfer. Note: it can only abort transfer that has not been started
+// Return true if a queued transfer is aborted, false if there is no transfer to abort
+bool hcd_edpt_abort_xfer(uint8_t rhport, uint8_t dev_addr, uint8_t ep_addr);
+
+// Submit a special transfer to send 8-byte Setup Packet, when complete hcd_event_xfer_complete() must be invoked
+bool hcd_setup_send(uint8_t rhport, uint8_t daddr, uint8_t const setup_packet[8]);
 
-bool hcd_edpt_busy(uint8_t dev_addr, uint8_t ep_addr);
-bool hcd_edpt_stalled(uint8_t dev_addr, uint8_t ep_addr);
-bool hcd_edpt_clear_stall(uint8_t dev_addr, uint8_t ep_addr);
+// clear stall, data toggle is also reset to DATA0
+bool hcd_edpt_clear_stall(uint8_t rhport, uint8_t dev_addr, uint8_t ep_addr);
 
 //--------------------------------------------------------------------+
-// Event API (implemented by stack)
+// USBH implemented API
 //--------------------------------------------------------------------+
 
+// Get device tree information of a device
+// USB device tree can be complicated and manged by USBH, this help HCD to retrieve
+// needed topology info to carry out its work
+extern void hcd_devtree_get_info(uint8_t dev_addr, hcd_devtree_info_t* devtree_info);
+
+//------------- Event API -------------//
+
 // Called by HCD to notify stack
 extern void hcd_event_handler(hcd_event_t const* event, bool in_isr);
 
 // Helper to send device attach event
-extern void hcd_event_device_attach(uint8_t rhport, bool in_isr);
+TU_ATTR_ALWAYS_INLINE static inline
+void hcd_event_device_attach(uint8_t rhport, bool in_isr) {
+  hcd_event_t event;
+  event.rhport              = rhport;
+  event.event_id            = HCD_EVENT_DEVICE_ATTACH;
+  event.connection.hub_addr = 0;
+  event.connection.hub_port = 0;
+
+  hcd_event_handler(&event, in_isr);
+}
 
 // Helper to send device removal event
-extern void hcd_event_device_remove(uint8_t rhport, bool in_isr);
+TU_ATTR_ALWAYS_INLINE static inline
+void hcd_event_device_remove(uint8_t rhport, bool in_isr) {
+  hcd_event_t event;
+  event.rhport              = rhport;
+  event.event_id            = HCD_EVENT_DEVICE_REMOVE;
+  event.connection.hub_addr = 0;
+  event.connection.hub_port = 0;
+
+  hcd_event_handler(&event, in_isr);
+}
 
 // Helper to send USB transfer event
-extern void hcd_event_xfer_complete(uint8_t dev_addr, uint8_t ep_addr, uint32_t xferred_bytes, xfer_result_t result, bool in_isr);
+TU_ATTR_ALWAYS_INLINE static inline
+void hcd_event_xfer_complete(uint8_t dev_addr, uint8_t ep_addr, uint32_t xferred_bytes, xfer_result_t result, bool in_isr) {
+  hcd_event_t event = {
+    .rhport   = 0, // TODO correct rhport
+    .event_id = HCD_EVENT_XFER_COMPLETE,
+    .dev_addr = dev_addr,
+  };
+  event.xfer_complete.ep_addr = ep_addr;
+  event.xfer_complete.result = result;
+  event.xfer_complete.len = xferred_bytes;
+
+  hcd_event_handler(&event, in_isr);
+}
 
 #ifdef __cplusplus
  }
diff --git a/src/host/hub.c b/src/host/hub.c
index f921027c7..e97014443 100644
--- a/src/host/hub.c
+++ b/src/host/hub.c
@@ -1,4 +1,4 @@
-/* 
+/*
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
@@ -26,11 +26,17 @@
 
 #include "tusb_option.h"
 
-#if (TUSB_OPT_HOST_ENABLED && CFG_TUH_HUB)
+#if (CFG_TUH_ENABLED && CFG_TUH_HUB)
 
+#include "hcd.h"
 #include "usbh.h"
+#include "usbh_pvt.h"
 #include "hub.h"
 
+// Debug level, TUSB_CFG_DEBUG must be at least this level for debug message
+#define HUB_DEBUG   2
+#define TU_LOG_DRV(...)   TU_LOG(HUB_DEBUG, __VA_ARGS__)
+
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
@@ -39,15 +45,22 @@ typedef struct
   uint8_t itf_num;
   uint8_t ep_in;
   uint8_t port_count;
-  uint8_t status_change; // data from status change interrupt endpoint
 
-  hub_port_status_response_t port_status;
+  CFG_TUH_MEM_ALIGN uint8_t status_change;
+  CFG_TUH_MEM_ALIGN hub_port_status_response_t port_status;
+  CFG_TUH_MEM_ALIGN hub_status_response_t hub_status;
 } hub_interface_t;
 
-CFG_TUSB_MEM_SECTION static hub_interface_t hub_data[CFG_TUSB_HOST_DEVICE_MAX];
-TU_ATTR_ALIGNED(4) CFG_TUSB_MEM_SECTION static uint8_t _hub_buffer[sizeof(descriptor_hub_desc_t)];
+CFG_TUH_MEM_SECTION static hub_interface_t hub_data[CFG_TUH_HUB];
+CFG_TUH_MEM_SECTION CFG_TUH_MEM_ALIGN static uint8_t _hub_buffer[sizeof(descriptor_hub_desc_t)];
 
-#if CFG_TUSB_DEBUG
+TU_ATTR_ALWAYS_INLINE
+static inline hub_interface_t* get_itf(uint8_t dev_addr)
+{
+  return &hub_data[dev_addr-1-CFG_TUH_DEVICE_MAX];
+}
+
+#if CFG_TUSB_DEBUG >= 2
 static char const* const _hub_feature_str[] =
 {
   [HUB_FEATURE_PORT_CONNECTION          ] = "PORT_CONNECTION",
@@ -70,13 +83,14 @@ static char const* const _hub_feature_str[] =
 //--------------------------------------------------------------------+
 // HUB
 //--------------------------------------------------------------------+
-bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature, tuh_control_complete_cb_t complete_cb)
+bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
+                            tuh_xfer_cb_t complete_cb, uintptr_t user_data)
 {
   tusb_control_request_t const request =
   {
     .bmRequestType_bit =
     {
-      .recipient = TUSB_REQ_RCPT_OTHER,
+      .recipient = (hub_port == 0) ? TUSB_REQ_RCPT_DEVICE : TUSB_REQ_RCPT_OTHER,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_OUT
     },
@@ -86,18 +100,29 @@ bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
     .wLength  = 0
   };
 
+  tuh_xfer_t xfer =
+  {
+    .daddr       = hub_addr,
+    .ep_addr     = 0,
+    .setup       = &request,
+    .buffer      = NULL,
+    .complete_cb = complete_cb,
+    .user_data   = user_data
+  };
+
   TU_LOG2("HUB Clear Feature: %s, addr = %u port = %u\r\n", _hub_feature_str[feature], hub_addr, hub_port);
-  TU_ASSERT( tuh_control_xfer(hub_addr, &request, NULL, complete_cb) );
+  TU_ASSERT( tuh_control_xfer(&xfer) );
   return true;
 }
 
-bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature, tuh_control_complete_cb_t complete_cb)
+bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
+                          tuh_xfer_cb_t complete_cb, uintptr_t user_data)
 {
   tusb_control_request_t const request =
   {
     .bmRequestType_bit =
     {
-      .recipient = TUSB_REQ_RCPT_OTHER,
+      .recipient = (hub_port == 0) ? TUSB_REQ_RCPT_DEVICE : TUSB_REQ_RCPT_OTHER,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_OUT
     },
@@ -107,23 +132,29 @@ bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature, t
     .wLength  = 0
   };
 
+  tuh_xfer_t xfer =
+  {
+    .daddr       = hub_addr,
+    .ep_addr     = 0,
+    .setup       = &request,
+    .buffer      = NULL,
+    .complete_cb = complete_cb,
+    .user_data   = user_data
+  };
+
   TU_LOG2("HUB Set Feature: %s, addr = %u port = %u\r\n", _hub_feature_str[feature], hub_addr, hub_port);
-  TU_ASSERT( tuh_control_xfer(hub_addr, &request, NULL, complete_cb) );
+  TU_ASSERT( tuh_control_xfer(&xfer) );
   return true;
 }
 
-bool hub_port_reset(uint8_t hub_addr, uint8_t hub_port, tuh_control_complete_cb_t complete_cb)
-{
-  return hub_port_set_feature(hub_addr, hub_port, HUB_FEATURE_PORT_RESET, complete_cb);
-}
-
-bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp, tuh_control_complete_cb_t complete_cb)
+bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp,
+                         tuh_xfer_cb_t complete_cb, uintptr_t user_data)
 {
   tusb_control_request_t const request =
   {
     .bmRequestType_bit =
     {
-      .recipient = TUSB_REQ_RCPT_OTHER,
+      .recipient = (hub_port == 0) ? TUSB_REQ_RCPT_DEVICE : TUSB_REQ_RCPT_OTHER,
       .type      = TUSB_REQ_TYPE_CLASS,
       .direction = TUSB_DIR_IN
     },
@@ -133,50 +164,78 @@ bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp, tuh_con
     .wLength  = 4
   };
 
+  tuh_xfer_t xfer =
+  {
+    .daddr       = hub_addr,
+    .ep_addr     = 0,
+    .setup       = &request,
+    .buffer      = resp,
+    .complete_cb = complete_cb,
+    .user_data   = user_data
+  };
+
   TU_LOG2("HUB Get Port Status: addr = %u port = %u\r\n", hub_addr, hub_port);
-  TU_ASSERT( tuh_control_xfer( hub_addr, &request, resp, complete_cb) );
+  TU_VERIFY( tuh_control_xfer(&xfer) );
   return true;
 }
 
 //--------------------------------------------------------------------+
 // CLASS-USBH API (don't require to verify parameters)
 //--------------------------------------------------------------------+
-void hub_init(void)
-{
-  tu_memclr(hub_data, CFG_TUSB_HOST_DEVICE_MAX*sizeof( hub_interface_t));
+bool hub_init(void) {
+  tu_memclr(hub_data, sizeof(hub_data));
+  return true;
 }
 
-bool hub_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t *p_length)
+bool hub_deinit(void) {
+  return true;
+}
+
+bool hub_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t max_len)
 {
-  // not support multiple TT yet
-  if ( itf_desc->bInterfaceProtocol > 1 ) return false;
+  (void) rhport;
+
+  TU_VERIFY(TUSB_CLASS_HUB == itf_desc->bInterfaceClass &&
+            0              == itf_desc->bInterfaceSubClass);
+
+  // hub driver does not support multiple TT yet
+  TU_VERIFY(itf_desc->bInterfaceProtocol <= 1);
 
-  //------------- Open Interrupt Status Pipe -------------//
-  tusb_desc_endpoint_t const *ep_desc;
-  ep_desc = (tusb_desc_endpoint_t const *) tu_desc_next(itf_desc);
+  // msc driver length is fixed
+  uint16_t const drv_len = sizeof(tusb_desc_interface_t) + sizeof(tusb_desc_endpoint_t);
+  TU_ASSERT(drv_len <= max_len);
 
-  TU_ASSERT(TUSB_DESC_ENDPOINT == ep_desc->bDescriptorType);
-  TU_ASSERT(TUSB_XFER_INTERRUPT == ep_desc->bmAttributes.xfer);
-  
-  TU_ASSERT(usbh_edpt_open(rhport, dev_addr, ep_desc));
+  //------------- Interrupt Status endpoint -------------//
+  tusb_desc_endpoint_t const *desc_ep = (tusb_desc_endpoint_t const *) tu_desc_next(itf_desc);
 
-  hub_data[dev_addr-1].itf_num = itf_desc->bInterfaceNumber;
-  hub_data[dev_addr-1].ep_in   = ep_desc->bEndpointAddress;
+  TU_ASSERT(TUSB_DESC_ENDPOINT  == desc_ep->bDescriptorType &&
+            TUSB_XFER_INTERRUPT == desc_ep->bmAttributes.xfer, 0);
 
-  (*p_length) = sizeof(tusb_desc_interface_t) + sizeof(tusb_desc_endpoint_t);
+  TU_ASSERT(tuh_edpt_open(dev_addr, desc_ep));
+
+  hub_interface_t* p_hub = get_itf(dev_addr);
+
+  p_hub->itf_num = itf_desc->bInterfaceNumber;
+  p_hub->ep_in   = desc_ep->bEndpointAddress;
 
   return true;
 }
 
 void hub_close(uint8_t dev_addr)
 {
-  tu_memclr(&hub_data[dev_addr-1], sizeof( hub_interface_t));
+  TU_VERIFY(dev_addr > CFG_TUH_DEVICE_MAX, );
+  hub_interface_t* p_hub = get_itf(dev_addr);
+
+  if (p_hub->ep_in) {
+    TU_LOG_DRV("  HUB close addr = %d\r\n", dev_addr);
+    tu_memclr(p_hub, sizeof( hub_interface_t));
+  }
 }
 
-bool hub_status_pipe_queue(uint8_t dev_addr)
+bool hub_edpt_status_xfer(uint8_t dev_addr)
 {
-  hub_interface_t * p_hub = &hub_data[dev_addr-1];
-  return usbh_edpt_xfer(dev_addr, p_hub->ep_in, &p_hub->status_change, 1);
+  hub_interface_t* hub_itf = get_itf(dev_addr);
+  return usbh_edpt_xfer(dev_addr, hub_itf->ep_in, &hub_itf->status_change, 1);
 }
 
 
@@ -184,12 +243,12 @@ bool hub_status_pipe_queue(uint8_t dev_addr)
 // Set Configure
 //--------------------------------------------------------------------+
 
-static bool config_set_port_power (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool config_port_power_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
+static void config_set_port_power (tuh_xfer_t* xfer);
+static void config_port_power_complete (tuh_xfer_t* xfer);
 
 bool hub_set_config(uint8_t dev_addr, uint8_t itf_num)
 {
-   hub_interface_t* p_hub = &hub_data[dev_addr-1];
+  hub_interface_t* p_hub = get_itf(dev_addr);
   TU_ASSERT(itf_num == p_hub->itf_num);
 
   // Get Hub Descriptor
@@ -207,17 +266,27 @@ bool hub_set_config(uint8_t dev_addr, uint8_t itf_num)
     .wLength  = sizeof(descriptor_hub_desc_t)
   };
 
-  TU_ASSERT( tuh_control_xfer(dev_addr, &request, _hub_buffer, config_set_port_power) );
+  tuh_xfer_t xfer =
+  {
+    .daddr       = dev_addr,
+    .ep_addr     = 0,
+    .setup       = &request,
+    .buffer      = _hub_buffer,
+    .complete_cb = config_set_port_power,
+    .user_data    = 0
+  };
+
+  TU_ASSERT( tuh_control_xfer(&xfer) );
 
   return true;
 }
 
-static bool config_set_port_power (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+static void config_set_port_power (tuh_xfer_t* xfer)
 {
-  (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
+  TU_ASSERT(XFER_RESULT_SUCCESS == xfer->result, );
 
-  hub_interface_t* p_hub = &hub_data[dev_addr-1];
+  uint8_t const daddr = xfer->daddr;
+  hub_interface_t* p_hub = get_itf(daddr);
 
   // only use number of ports in hub descriptor
   descriptor_hub_desc_t const* desc_hub = (descriptor_hub_desc_t const*) _hub_buffer;
@@ -227,70 +296,118 @@ static bool config_set_port_power (uint8_t dev_addr, tusb_control_request_t cons
 
   // Set Port Power to be able to detect connection, starting with port 1
   uint8_t const hub_port = 1;
-  return hub_port_set_feature(dev_addr, hub_port, HUB_FEATURE_PORT_POWER, config_port_power_complete);
+  hub_port_set_feature(daddr, hub_port, HUB_FEATURE_PORT_POWER, config_port_power_complete, 0);
 }
 
-static bool config_port_power_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+static void config_port_power_complete (tuh_xfer_t* xfer)
 {
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
-   hub_interface_t* p_hub = &hub_data[dev_addr-1];
+  TU_ASSERT(XFER_RESULT_SUCCESS == xfer->result, );
 
-  if (request->wIndex == p_hub->port_count)
+  uint8_t const daddr = xfer->daddr;
+  hub_interface_t* p_hub = get_itf(daddr);
+
+  if (xfer->setup->wIndex == p_hub->port_count)
   {
     // All ports are power -> queue notification status endpoint and
     // complete the SET CONFIGURATION
-    TU_ASSERT( usbh_edpt_xfer(dev_addr, p_hub->ep_in, &p_hub->status_change, 1) );
+    TU_ASSERT( usbh_edpt_xfer(daddr, p_hub->ep_in, &p_hub->status_change, 1), );
 
-    usbh_driver_set_config_complete(dev_addr, p_hub->itf_num);
+    usbh_driver_set_config_complete(daddr, p_hub->itf_num);
   }else
   {
     // power next port
-    uint8_t const hub_port = (uint8_t) (request->wIndex + 1);
-    return hub_port_set_feature(dev_addr, hub_port, HUB_FEATURE_PORT_POWER, config_port_power_complete);
+    uint8_t const hub_port = (uint8_t) (xfer->setup->wIndex + 1);
+    hub_port_set_feature(daddr, hub_port, HUB_FEATURE_PORT_POWER, config_port_power_complete, 0);
   }
-
-  return true;
 }
 
 //--------------------------------------------------------------------+
 // Connection Changes
 //--------------------------------------------------------------------+
 
-static bool connection_get_status_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool connection_clear_conn_change_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool connection_port_reset_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
+static void hub_port_get_status_complete (tuh_xfer_t* xfer);
+static void hub_get_status_complete (tuh_xfer_t* xfer);
+static void connection_clear_conn_change_complete (tuh_xfer_t* xfer);
+static void connection_port_reset_complete (tuh_xfer_t* xfer);
 
 // callback as response of interrupt endpoint polling
-bool hub_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
-{
+bool hub_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes) {
   (void) xferred_bytes; // TODO can be more than 1 for hub with lots of ports
   (void) ep_addr;
-  TU_ASSERT(result == XFER_RESULT_SUCCESS);
+  TU_VERIFY(result == XFER_RESULT_SUCCESS);
 
-  hub_interface_t * p_hub = &hub_data[dev_addr-1];
+  hub_interface_t* p_hub = get_itf(dev_addr);
 
-  TU_LOG2("  Port Status Change = 0x%02X\r\n", p_hub->status_change);
+  uint8_t const status_change = p_hub->status_change;
+  TU_LOG2("  Hub Status Change = 0x%02X\r\n", status_change);
 
-  // Hub ignore bit0 in status change
-  for (uint8_t port=1; port <= p_hub->port_count; port++)
-  {
-    if ( tu_bit_test(p_hub->status_change, port) )
-    {
-      hub_port_get_status(dev_addr, port, &p_hub->port_status, connection_get_status_complete);
-      break;
+  if ( status_change == 0 ) {
+    // The status change event was neither for the hub, nor for any of its ports.
+    // This shouldn't happen, but it does with some devices.
+    // Initiate the next interrupt poll here.
+    return hub_edpt_status_xfer(dev_addr);
+  }
+
+  if (tu_bit_test(status_change, 0)) {
+    // Hub bit 0 is for the hub device events
+    if (hub_port_get_status(dev_addr, 0, &p_hub->hub_status, hub_get_status_complete, 0) == false) {
+      //Hub status control transfer failed, retry
+      hub_edpt_status_xfer(dev_addr);
+    }
+  }
+  else {
+    // Hub bits 1 to n are hub port events
+    for (uint8_t port=1; port <= p_hub->port_count; port++) {
+      if ( tu_bit_test(status_change, port) ) {
+        if (hub_port_get_status(dev_addr, port, &p_hub->port_status, hub_port_get_status_complete, 0) == false) {
+          //Hub status control transfer failed, retry
+          hub_edpt_status_xfer(dev_addr);
+        }
+        break;
+      }
     }
   }
 
   // NOTE: next status transfer is queued by usbh.c after handling this request
-
   return true;
 }
 
-static bool connection_get_status_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+static void hub_clear_feature_complete_stub(tuh_xfer_t* xfer)
+{
+  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+  hub_edpt_status_xfer(xfer->daddr);
+}
+
+static void hub_get_status_complete (tuh_xfer_t* xfer)
+{
+  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+
+  uint8_t const daddr = xfer->daddr;
+  hub_interface_t* p_hub = get_itf(daddr);
+  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
+  TU_ASSERT(port_num == 0 , );
+
+  TU_LOG2("HUB Got hub status, addr = %u, status = %04x\r\n", daddr, p_hub->hub_status.change.value);
+
+  if (p_hub->hub_status.change.local_power_source)
+  {
+    TU_LOG2("HUB Local Power Change, addr = %u\r\n", daddr);
+    hub_port_clear_feature(daddr, port_num, HUB_FEATURE_HUB_LOCAL_POWER_CHANGE, hub_clear_feature_complete_stub, 0);
+  }
+  else if (p_hub->hub_status.change.over_current)
+  {
+    TU_LOG1("HUB Over Current, addr = %u\r\n", daddr);
+    hub_port_clear_feature(daddr, port_num, HUB_FEATURE_HUB_OVER_CURRENT_CHANGE, hub_clear_feature_complete_stub, 0);
+  }
+}
+
+static void hub_port_get_status_complete (tuh_xfer_t* xfer)
 {
-  TU_ASSERT(result == XFER_RESULT_SUCCESS);
-  hub_interface_t * p_hub = &hub_data[dev_addr-1];
-  uint8_t const port_num = (uint8_t) request->wIndex;
+  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
+
+  uint8_t const daddr = xfer->daddr;
+  hub_interface_t* p_hub = get_itf(daddr);
+  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
 
   // Connection change
   if (p_hub->port_status.change.connection)
@@ -299,73 +416,89 @@ static bool connection_get_status_complete (uint8_t dev_addr, tusb_control_reque
     //TU_VERIFY(port_status.status_current.port_power && port_status.status_current.port_enable, );
 
     // Acknowledge Port Connection Change
-    hub_port_clear_feature(dev_addr, port_num, HUB_FEATURE_PORT_CONNECTION_CHANGE, connection_clear_conn_change_complete);
+    hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_CONNECTION_CHANGE, connection_clear_conn_change_complete, 0);
   }else
   {
-    // Other changes are: Enable, Suspend, Over Current, Reset, L1 state
+    // Clear other port status change interrupts. TODO Not currently handled - just cleared.
+    if (p_hub->port_status.change.port_enable)
+    {
+      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_ENABLE_CHANGE, hub_clear_feature_complete_stub, 0);
+    }
+    else if (p_hub->port_status.change.suspend)
+    {
+      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_SUSPEND_CHANGE, hub_clear_feature_complete_stub, 0);
+    }
+    else if (p_hub->port_status.change.over_current)
+    {
+      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_OVER_CURRENT_CHANGE, hub_clear_feature_complete_stub, 0);
+    }
+    else if (p_hub->port_status.change.reset)
+    {
+      hub_port_clear_feature(daddr, port_num, HUB_FEATURE_PORT_RESET_CHANGE, hub_clear_feature_complete_stub, 0);
+    }
+    // Other changes are: L1 state
     // TODO clear change
 
-    // prepare for next hub status
-    // TODO continue with status_change, or maybe we can do it again with status
-    hub_status_pipe_queue(dev_addr);
+    else
+    {
+      // prepare for next hub status
+      // TODO continue with status_change, or maybe we can do it again with status
+      hub_edpt_status_xfer(daddr);
+    }
   }
-
-  return true;
 }
 
-static bool connection_clear_conn_change_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+static void connection_clear_conn_change_complete (tuh_xfer_t* xfer)
 {
-  TU_ASSERT(result == XFER_RESULT_SUCCESS);
+  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
 
-  hub_interface_t * p_hub = &hub_data[dev_addr-1];
-  uint8_t const port_num = (uint8_t) request->wIndex;
+  uint8_t const daddr = xfer->daddr;
+  hub_interface_t* p_hub = get_itf(daddr);
+  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
 
   if ( p_hub->port_status.status.connection )
   {
     // Reset port if attach event
-    hub_port_reset(dev_addr, port_num, connection_port_reset_complete);
+    hub_port_reset(daddr, port_num, connection_port_reset_complete, 0);
   }else
   {
     // submit detach event
     hcd_event_t event =
     {
-      .rhport     = usbh_get_rhport(dev_addr),
+      .rhport     = usbh_get_rhport(daddr),
       .event_id   = HCD_EVENT_DEVICE_REMOVE,
       .connection =
        {
-         .hub_addr = dev_addr,
+         .hub_addr = daddr,
          .hub_port = port_num
        }
     };
 
     hcd_event_handler(&event, false);
   }
-
-  return true;
 }
 
-static bool connection_port_reset_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+static void connection_port_reset_complete (tuh_xfer_t* xfer)
 {
-  TU_ASSERT(result == XFER_RESULT_SUCCESS);
+  TU_ASSERT(xfer->result == XFER_RESULT_SUCCESS, );
 
-  // usbh_hub_t * p_hub = &hub_data[dev_addr-1];
-  uint8_t const port_num = (uint8_t) request->wIndex;
+  uint8_t const daddr = xfer->daddr;
+  // hub_interface_t* p_hub = get_itf(daddr);
+  uint8_t const port_num = (uint8_t) tu_le16toh(xfer->setup->wIndex);
 
   // submit attach event
   hcd_event_t event =
   {
-    .rhport     = usbh_get_rhport(dev_addr),
+    .rhport     = usbh_get_rhport(daddr),
     .event_id   = HCD_EVENT_DEVICE_ATTACH,
     .connection =
     {
-      .hub_addr = dev_addr,
+      .hub_addr = daddr,
       .hub_port = port_num
     }
   };
 
   hcd_event_handler(&event, false);
-
-  return true;
 }
 
 #endif
diff --git a/src/host/hub.h b/src/host/hub.h
index a5111b8e7..385efe6b2 100644
--- a/src/host/hub.h
+++ b/src/host/hub.h
@@ -171,21 +171,43 @@ typedef struct {
 
 TU_VERIFY_STATIC( sizeof(hub_port_status_response_t) == 4, "size is not correct");
 
-bool hub_port_clear_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature, tuh_control_complete_cb_t complete_cb);
-bool hub_port_set_feature(uint8_t hub_addr, uint8_t hub_port, uint8_t feature, tuh_control_complete_cb_t complete_cb);
+// Clear feature
+bool hub_port_clear_feature (uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
+                             tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Set feature
+bool hub_port_set_feature   (uint8_t hub_addr, uint8_t hub_port, uint8_t feature,
+                             tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get port status
+bool hub_port_get_status    (uint8_t hub_addr, uint8_t hub_port, void* resp,
+                             tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get status from Interrupt endpoint
+bool hub_edpt_status_xfer(uint8_t dev_addr);
+
+// Reset a port
+TU_ATTR_ALWAYS_INLINE static inline
+bool hub_port_reset(uint8_t hub_addr, uint8_t hub_port, tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return hub_port_set_feature(hub_addr, hub_port, HUB_FEATURE_PORT_RESET, complete_cb, user_data);
+}
+
+// Clear Reset Change
+TU_ATTR_ALWAYS_INLINE static inline
+bool hub_port_clear_reset_change(uint8_t hub_addr, uint8_t hub_port, tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return hub_port_clear_feature(hub_addr, hub_port, HUB_FEATURE_PORT_RESET_CHANGE, complete_cb, user_data);
+}
 
-bool hub_port_reset(uint8_t hub_addr, uint8_t hub_port, tuh_control_complete_cb_t complete_cb);
-bool hub_port_get_status(uint8_t hub_addr, uint8_t hub_port, void* resp, tuh_control_complete_cb_t complete_cb);
-bool hub_status_pipe_queue(uint8_t dev_addr);
 
 //--------------------------------------------------------------------+
 // Internal Class Driver API
 //--------------------------------------------------------------------+
-void hub_init(void);
-bool hub_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t *p_length);
-bool hub_set_config(uint8_t dev_addr, uint8_t itf_num);
-bool hub_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
-void hub_close(uint8_t dev_addr);
+bool hub_init       (void);
+bool hub_deinit     (void);
+bool hub_open       (uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *itf_desc, uint16_t max_len);
+bool hub_set_config (uint8_t dev_addr, uint8_t itf_num);
+bool hub_xfer_cb    (uint8_t dev_addr, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes);
+void hub_close      (uint8_t dev_addr);
 
 #ifdef __cplusplus
  }
diff --git a/src/host/usbh.c b/src/host/usbh.c
index ca0653409..7a47f5056 100644
--- a/src/host/usbh.c
+++ b/src/host/usbh.c
@@ -1,4 +1,4 @@
-/* 
+/*
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
@@ -24,196 +24,433 @@
  * This file is part of the TinyUSB stack.
  */
 
-#include "common/tusb_common.h"
+#include "tusb_option.h"
 
-#if TUSB_OPT_HOST_ENABLED
+#if CFG_TUH_ENABLED
 
+#include "host/hcd.h"
+#include "tusb.h"
+#include "host/usbh_pvt.h"
+#include "hub.h"
+
+//--------------------------------------------------------------------+
+// USBH Configuration
+//--------------------------------------------------------------------+
 #ifndef CFG_TUH_TASK_QUEUE_SZ
-#define CFG_TUH_TASK_QUEUE_SZ   16
+  #define CFG_TUH_TASK_QUEUE_SZ   16
+#endif
+
+#ifndef CFG_TUH_INTERFACE_MAX
+  #define CFG_TUH_INTERFACE_MAX   8
 #endif
 
 //--------------------------------------------------------------------+
-// INCLUDE
+// Weak stubs: invoked if no strong implementation is available
 //--------------------------------------------------------------------+
-#include "tusb.h"
-#include "hub.h"
-#include "usbh_hcd.h"
+TU_ATTR_WEAK bool hcd_deinit(uint8_t rhport) {
+  (void) rhport;
+  return false;
+}
+
+TU_ATTR_WEAK bool hcd_configure(uint8_t rhport, uint32_t cfg_id, const void* cfg_param) {
+  (void) rhport;
+  (void) cfg_id;
+  (void) cfg_param;
+  return false;
+}
+
+TU_ATTR_WEAK void tuh_event_hook_cb(uint8_t rhport, uint32_t eventid, bool in_isr) {
+  (void) rhport;
+  (void) eventid;
+  (void) in_isr;
+}
+
+//--------------------------------------------------------------------+
+// USBH-HCD common data structure
+//--------------------------------------------------------------------+
+typedef struct {
+  // port
+  uint8_t rhport;
+  uint8_t hub_addr;
+  uint8_t hub_port;
+
+  struct TU_ATTR_PACKED {
+             uint8_t speed       : 4; // packed speed to save footprint
+    volatile uint8_t enumerating : 1; // enumeration is in progress, false if not connected or all interfaces are configured
+    uint8_t TU_RESERVED : 3;
+  };
+} usbh_dev0_t;
+
+typedef struct {
+  // port, must be same layout as usbh_dev0_t
+  uint8_t rhport;
+  uint8_t hub_addr;
+  uint8_t hub_port;
+  uint8_t speed;
+
+  // Device State
+  struct TU_ATTR_PACKED {
+    volatile uint8_t connected  : 1; // After 1st transfer
+    volatile uint8_t addressed  : 1; // After SET_ADDR
+    volatile uint8_t configured : 1; // After SET_CONFIG and all drivers are configured
+    volatile uint8_t suspended  : 1; // Bus suspended
+
+    // volatile uint8_t removing : 1; // Physically disconnected, waiting to be processed by usbh
+  };
+
+  // Device Descriptor
+  uint8_t  ep0_size;
+
+  uint16_t vid;
+  uint16_t pid;
+
+  uint8_t  i_manufacturer;
+  uint8_t  i_product;
+  uint8_t  i_serial;
+
+  // Configuration Descriptor
+  // uint8_t interface_count; // bNumInterfaces alias
+
+  // Endpoint & Interface
+  uint8_t itf2drv[CFG_TUH_INTERFACE_MAX];  // map interface number to driver (0xff is invalid)
+  uint8_t ep2drv[CFG_TUH_ENDPOINT_MAX][2]; // map endpoint to driver ( 0xff is invalid ), can use only 4-bit each
+
+  tu_edpt_state_t ep_status[CFG_TUH_ENDPOINT_MAX][2];
+
+#if CFG_TUH_API_EDPT_XFER
+  // TODO array can be CFG_TUH_ENDPOINT_MAX-1
+  struct {
+    tuh_xfer_cb_t complete_cb;
+    uintptr_t user_data;
+  }ep_callback[CFG_TUH_ENDPOINT_MAX][2];
+#endif
+
+} usbh_device_t;
 
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
-#if CFG_TUSB_DEBUG >= 2
-  #define DRIVER_NAME(_name)    .name = _name,
+#if CFG_TUSB_DEBUG >= CFG_TUH_LOG_LEVEL
+  #define DRIVER_NAME(_name)  _name
 #else
-  #define DRIVER_NAME(_name)
+  #define DRIVER_NAME(_name)  NULL
 #endif
 
-static usbh_class_driver_t const usbh_class_drivers[] =
-{
-  #if CFG_TUH_CDC
+static usbh_class_driver_t const usbh_class_drivers[] = {
+    #if CFG_TUH_CDC
     {
-      DRIVER_NAME("CDC")
-      .class_code = TUSB_CLASS_CDC,
-      .init       = cdch_init,
-      .open       = cdch_open,
-      .set_config = cdch_set_config,
-      .xfer_cb    = cdch_xfer_cb,
-      .close      = cdch_close
+        .name       = DRIVER_NAME("CDC"),
+        .init       = cdch_init,
+        .deinit     = cdch_deinit,
+        .open       = cdch_open,
+        .set_config = cdch_set_config,
+        .xfer_cb    = cdch_xfer_cb,
+        .close      = cdch_close
     },
-  #endif
+    #endif
 
-  #if CFG_TUH_MSC
+    #if CFG_TUH_MSC
     {
-      DRIVER_NAME("MSC")
-      .class_code = TUSB_CLASS_MSC,
-      .init       = msch_init,
-      .open       = msch_open,
-      .set_config = msch_set_config,
-      .xfer_cb    = msch_xfer_cb,
-      .close      = msch_close
+        .name       = DRIVER_NAME("MSC"),
+        .init       = msch_init,
+        .deinit     = msch_deinit,
+        .open       = msch_open,
+        .set_config = msch_set_config,
+        .xfer_cb    = msch_xfer_cb,
+        .close      = msch_close
     },
-  #endif
+    #endif
 
-  #if CFG_TUH_HID
+    #if CFG_TUH_HID
     {
-      DRIVER_NAME("HID")
-      .class_code = TUSB_CLASS_HID,
-      .init       = hidh_init,
-      .open       = hidh_open,
-      .set_config = hidh_set_config,
-      .xfer_cb    = hidh_xfer_cb,
-      .close      = hidh_close
+        .name       = DRIVER_NAME("HID"),
+        .init       = hidh_init,
+        .deinit     = hidh_deinit,
+        .open       = hidh_open,
+        .set_config = hidh_set_config,
+        .xfer_cb    = hidh_xfer_cb,
+        .close      = hidh_close
     },
-  #endif
+    #endif
 
-  #if CFG_TUH_HUB
+    #if CFG_TUH_HUB
     {
-      DRIVER_NAME("HUB")
-      .class_code = TUSB_CLASS_HUB,
-      .init       = hub_init,
-      .open       = hub_open,
-      .set_config = hub_set_config,
-      .xfer_cb    = hub_xfer_cb,
-      .close      = hub_close
+        .name       = DRIVER_NAME("HUB"),
+        .init       = hub_init,
+        .deinit     = hub_deinit,
+        .open       = hub_open,
+        .set_config = hub_set_config,
+        .xfer_cb    = hub_xfer_cb,
+        .close      = hub_close
     },
-  #endif
+    #endif
 
-  #if CFG_TUH_VENDOR
+    #if CFG_TUH_VENDOR
     {
-      DRIVER_NAME("VENDOR")
-      .class_code = TUSB_CLASS_VENDOR_SPECIFIC,
+      .name       = DRIVER_NAME("VENDOR"),
       .init       = cush_init,
-      .open       = cush_open_subtask,
+      .deinit     = cush_deinit,
+      .open       = cush_open,
+      .set_config = cush_set_config,
       .xfer_cb    = cush_isr,
       .close      = cush_close
     }
-  #endif
+    #endif
 };
 
-enum { USBH_CLASS_DRIVER_COUNT = TU_ARRAY_SIZE(usbh_class_drivers) };
+enum { BUILTIN_DRIVER_COUNT = TU_ARRAY_SIZE(usbh_class_drivers) };
+enum { CONFIG_NUM = 1 }; // default to use configuration 1
 
-enum { RESET_DELAY = 500 };  // 200 USB specs say only 50ms but many devices require much longer
+// Additional class drivers implemented by application
+tu_static usbh_class_driver_t const * _app_driver = NULL;
+tu_static uint8_t _app_driver_count = 0;
 
-enum { CONFIG_NUM = 1 }; // default to use configuration 1
+#define TOTAL_DRIVER_COUNT    (_app_driver_count + BUILTIN_DRIVER_COUNT)
 
+static inline usbh_class_driver_t const *get_driver(uint8_t drv_id) {
+  usbh_class_driver_t const *driver = NULL;
+
+  if ( drv_id < _app_driver_count ) {
+    driver = &_app_driver[drv_id];
+  } else if ( drv_id < TOTAL_DRIVER_COUNT && BUILTIN_DRIVER_COUNT > 0) {
+    driver = &usbh_class_drivers[drv_id - _app_driver_count];
+  }
+
+  return driver;
+}
 
 //--------------------------------------------------------------------+
 // INTERNAL OBJECT & FUNCTION DECLARATION
 //--------------------------------------------------------------------+
 
-static bool _usbh_initialized = false;
+// sum of end device + hub
+#define TOTAL_DEVICES   (CFG_TUH_DEVICE_MAX + CFG_TUH_HUB)
 
-// including zero-address
-CFG_TUSB_MEM_SECTION usbh_device_t _usbh_devices[CFG_TUSB_HOST_DEVICE_MAX+1];
+static uint8_t _usbh_controller = TUSB_INDEX_INVALID_8;
+
+// Device with address = 0 for enumeration
+static usbh_dev0_t _dev0;
+
+// all devices excluding zero-address
+// hub address start from CFG_TUH_DEVICE_MAX+1
+// TODO: hub can has its own simpler struct to save memory
+static usbh_device_t _usbh_devices[TOTAL_DEVICES];
+
+// Mutex for claiming endpoint
+#if OSAL_MUTEX_REQUIRED
+  static osal_mutex_def_t _usbh_mutexdef;
+  static osal_mutex_t _usbh_mutex;
+#else
+  #define _usbh_mutex   NULL
+#endif
 
 // Event queue
-// role device/host is used by OS NONE for mutex (disable usb isr)
-OSAL_QUEUE_DEF(OPT_MODE_HOST, _usbh_qdef, CFG_TUH_TASK_QUEUE_SZ, hcd_event_t);
+// usbh_int_set is used as mutex in OS NONE config
+OSAL_QUEUE_DEF(usbh_int_set, _usbh_qdef, CFG_TUH_TASK_QUEUE_SZ, hcd_event_t);
 static osal_queue_t _usbh_q;
 
-CFG_TUSB_MEM_SECTION CFG_TUSB_MEM_ALIGN static uint8_t _usbh_ctrl_buf[CFG_TUH_ENUMERATION_BUFSZIE];
+CFG_TUH_MEM_SECTION CFG_TUH_MEM_ALIGN
+static uint8_t _usbh_ctrl_buf[CFG_TUH_ENUMERATION_BUFSIZE];
+
+// Control transfers: since most controllers do not support multiple control transfers
+// on multiple devices concurrently and control transfers are not used much except for
+// enumeration, we will only execute control transfers one at a time.
+CFG_TUH_MEM_SECTION struct {
+  CFG_TUH_MEM_ALIGN tusb_control_request_t request;
+  uint8_t* buffer;
+  tuh_xfer_cb_t complete_cb;
+  uintptr_t user_data;
+
+  uint8_t daddr;
+  volatile uint8_t stage;
+  volatile uint16_t actual_len;
+}_ctrl_xfer;
+
+//------------- Helper Function -------------//
+
+TU_ATTR_ALWAYS_INLINE static inline usbh_device_t* get_device(uint8_t dev_addr) {
+  TU_VERIFY(dev_addr > 0 && dev_addr <= TOTAL_DEVICES, NULL);
+  return &_usbh_devices[dev_addr-1];
+}
 
-//------------- Helper Function Prototypes -------------//
 static bool enum_new_device(hcd_event_t* event);
-static void process_device_unplugged(uint8_t rhport, uint8_t hub_addr, uint8_t hub_port);
+static void process_removing_device(uint8_t rhport, uint8_t hub_addr, uint8_t hub_port);
+static bool usbh_edpt_control_open(uint8_t dev_addr, uint8_t max_packet_size);
+static bool usbh_control_xfer_cb (uint8_t daddr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes);
 
-// from usbh_control.c
-extern bool usbh_control_xfer_cb (uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes);
+#if CFG_TUSB_OS == OPT_OS_NONE
+// TODO rework time-related function later
+// weak and overridable
+TU_ATTR_WEAK void osal_task_delay(uint32_t msec) {
+  const uint32_t start = hcd_frame_number(_usbh_controller);
+  while ( ( hcd_frame_number(_usbh_controller) - start ) < msec ) {}
+}
+#endif
+
+TU_ATTR_ALWAYS_INLINE static inline bool queue_event(hcd_event_t const * event, bool in_isr) {
+  TU_ASSERT(osal_queue_send(_usbh_q, event, in_isr));
+  tuh_event_hook_cb(event->rhport, event->event_id, in_isr);
+  return true;
+}
 
 //--------------------------------------------------------------------+
-// PUBLIC API (Parameter Verification is required)
+// Device API
 //--------------------------------------------------------------------+
-bool tuh_device_configured(uint8_t dev_addr)
-{
-  return _usbh_devices[dev_addr].configured;
+
+bool tuh_mounted(uint8_t dev_addr) {
+  usbh_device_t *dev = get_device(dev_addr);
+  TU_VERIFY(dev);
+  return dev->configured;
 }
 
-tusb_speed_t tuh_device_get_speed (uint8_t const dev_addr)
-{
-  TU_ASSERT( dev_addr <= CFG_TUSB_HOST_DEVICE_MAX, TUSB_SPEED_INVALID);
-  return (tusb_speed_t) _usbh_devices[dev_addr].speed;
+bool tuh_vid_pid_get(uint8_t dev_addr, uint16_t *vid, uint16_t *pid) {
+  *vid = *pid = 0;
+
+  usbh_device_t const *dev = get_device(dev_addr);
+  TU_VERIFY(dev && dev->addressed && dev->vid != 0);
+
+  *vid = dev->vid;
+  *pid = dev->pid;
+
+  return true;
 }
 
-#if CFG_TUSB_OS == OPT_OS_NONE
-void osal_task_delay(uint32_t msec)
-{
-  (void) msec;
+tusb_speed_t tuh_speed_get(uint8_t dev_addr) {
+  usbh_device_t *dev = get_device(dev_addr);
+  return (tusb_speed_t) (dev ? get_device(dev_addr)->speed : _dev0.speed);
+}
 
-  const uint32_t start = hcd_frame_number(TUH_OPT_RHPORT);
-  while ( ( hcd_frame_number(TUH_OPT_RHPORT) - start ) < msec ) {}
+bool tuh_rhport_is_active(uint8_t rhport) {
+  return _usbh_controller == rhport;
+}
+
+bool tuh_rhport_reset_bus(uint8_t rhport, bool active) {
+  TU_VERIFY(tuh_rhport_is_active(rhport));
+  if ( active ) {
+    hcd_port_reset(rhport);
+  } else {
+    hcd_port_reset_end(rhport);
+  }
+  return true;
 }
-#endif
 
 //--------------------------------------------------------------------+
-// CLASS-USBD API (don't require to verify parameters)
+// PUBLIC API (Parameter Verification is required)
 //--------------------------------------------------------------------+
 
-bool tuh_inited(void)
-{
-  return _usbh_initialized;
+bool tuh_configure(uint8_t rhport, uint32_t cfg_id, const void *cfg_param) {
+  return hcd_configure(rhport, cfg_id, cfg_param);
 }
 
-bool tuh_init(uint8_t rhport)
-{
-  // skip if already initialized
-  if (_usbh_initialized) return _usbh_initialized;
+static void clear_device(usbh_device_t* dev) {
+  tu_memclr(dev, sizeof(usbh_device_t));
+  memset(dev->itf2drv, TUSB_INDEX_INVALID_8, sizeof(dev->itf2drv)); // invalid mapping
+  memset(dev->ep2drv , TUSB_INDEX_INVALID_8, sizeof(dev->ep2drv )); // invalid mapping
+}
 
-  TU_LOG2("USBH init\r\n");
+bool tuh_inited(void) {
+  return _usbh_controller != TUSB_INDEX_INVALID_8;
+}
+
+bool tuh_init(uint8_t rhport) {
+  // skip if already initialized
+  if (tuh_rhport_is_active(rhport)) return true;
 
-  tu_memclr(_usbh_devices, sizeof(usbh_device_t)*(CFG_TUSB_HOST_DEVICE_MAX+1));
+  TU_LOG_USBH("USBH init on controller %u\r\n", rhport);
 
-  //------------- Enumeration & Reporter Task init -------------//
-  _usbh_q = osal_queue_create( &_usbh_qdef );
-  TU_ASSERT(_usbh_q != NULL);
+  // Init host stack if not already
+  if (!tuh_inited()) {
+    TU_LOG_INT_USBH(sizeof(usbh_device_t));
+    TU_LOG_INT_USBH(sizeof(hcd_event_t));
+    TU_LOG_INT_USBH(sizeof(_ctrl_xfer));
+    TU_LOG_INT_USBH(sizeof(tuh_xfer_t));
+    TU_LOG_INT_USBH(sizeof(tu_fifo_t));
+    TU_LOG_INT_USBH(sizeof(tu_edpt_stream_t));
 
-  //------------- 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];
+    // Event queue
+    _usbh_q = osal_queue_create(&_usbh_qdef);
+    TU_ASSERT(_usbh_q != NULL);
 
-#if CFG_TUSB_OS != OPT_OS_NONE
-    dev->mutex = osal_mutex_create(&dev->mutexdef);
-    TU_ASSERT(dev->mutex);
+#if OSAL_MUTEX_REQUIRED
+    // Init mutex
+    _usbh_mutex = osal_mutex_create(&_usbh_mutexdef);
+    TU_ASSERT(_usbh_mutex);
 #endif
 
-    memset(dev->itf2drv, 0xff, sizeof(dev->itf2drv)); // invalid mapping
-    memset(dev->ep2drv , 0xff, sizeof(dev->ep2drv )); // invalid mapping
-  }
+    // Get application driver if available
+    if (usbh_app_driver_get_cb) {
+      _app_driver = usbh_app_driver_get_cb(&_app_driver_count);
+    }
+
+    // Device
+    tu_memclr(&_dev0, sizeof(_dev0));
+    tu_memclr(_usbh_devices, sizeof(_usbh_devices));
+    tu_memclr(&_ctrl_xfer, sizeof(_ctrl_xfer));
+
+    for (uint8_t i = 0; i < TOTAL_DEVICES; i++) {
+      clear_device(&_usbh_devices[i]);
+    }
 
-  // Class drivers init
-  for (uint8_t drv_id = 0; drv_id < USBH_CLASS_DRIVER_COUNT; drv_id++)
-  {
-    TU_LOG2("%s init\r\n", usbh_class_drivers[drv_id].name);
-    usbh_class_drivers[drv_id].init();
+    // Class drivers
+    for (uint8_t drv_id = 0; drv_id < TOTAL_DRIVER_COUNT; drv_id++) {
+      usbh_class_driver_t const* driver = get_driver(drv_id);
+      if (driver) {
+        TU_LOG_USBH("%s init\r\n", driver->name);
+        driver->init();
+      }
+    }
   }
 
+  // Init host controller
+  _usbh_controller = rhport;;
   TU_ASSERT(hcd_init(rhport));
   hcd_int_enable(rhport);
 
-  _usbh_initialized = true;
   return true;
 }
 
+bool tuh_deinit(uint8_t rhport) {
+  if (!tuh_rhport_is_active(rhport)) return true;
+
+  // deinit host controller
+  hcd_int_disable(rhport);
+  hcd_deinit(rhport);
+  _usbh_controller = TUSB_INDEX_INVALID_8;
+
+  // "unplug" all devices on this rhport (hub_addr = 0, hub_port = 0)
+  process_removing_device(rhport, 0, 0);
+
+  // deinit host stack if no controller is active
+  if (!tuh_inited()) {
+    // Class drivers
+    for (uint8_t drv_id = 0; drv_id < TOTAL_DRIVER_COUNT; drv_id++) {
+      usbh_class_driver_t const* driver = get_driver(drv_id);
+      if (driver && driver->deinit) {
+        TU_LOG_USBH("%s deinit\r\n", driver->name);
+        driver->deinit();
+      }
+    }
+
+    osal_queue_delete(_usbh_q);
+    _usbh_q = NULL;
+
+    #if OSAL_MUTEX_REQUIRED
+    // TODO make sure there is no task waiting on this mutex
+    osal_mutex_delete(_usbh_mutex);
+    _usbh_mutex = NULL;
+    #endif
+  }
+
+  return true;
+}
+
+bool tuh_task_event_ready(void) {
+  // Skip if stack is not initialized
+  if ( !tuh_inited() ) return false;
+
+  return !osal_queue_empty(_usbh_q);
+}
+
 /* USB Host Driver task
  * This top level thread manages all host controller event and delegates events to class-specific drivers.
  * This should be called periodically within the mainloop or rtos thread.
@@ -232,771 +469,1277 @@ bool tuh_init(uint8_t rhport)
     }
     @endcode
  */
-void tuh_task(void)
-{
+void tuh_task_ext(uint32_t timeout_ms, bool in_isr) {
+  (void) in_isr; // not implemented yet
+
   // Skip if stack is not initialized
-  if ( !tusb_inited() ) return;
+  if (!tuh_inited()) return;
 
   // Loop until there is no more events in the queue
-  while (1)
-  {
+  while (1) {
     hcd_event_t event;
-    if ( !osal_queue_receive(_usbh_q, &event) ) return;
+    if (!osal_queue_receive(_usbh_q, &event, timeout_ms)) return;
 
-    switch (event.event_id)
-    {
+    switch (event.event_id) {
       case HCD_EVENT_DEVICE_ATTACH:
-        // TODO due to the shared _usbh_ctrl_buf, we must complete enumerating
-        // one device before enumerating another one.
-        TU_LOG2("USBH DEVICE ATTACH\r\n");
-        enum_new_device(&event);
-      break;
+        // due to the shared _usbh_ctrl_buf, we must complete enumerating one device before enumerating another one.
+        // TODO better to have an separated queue for newly attached devices
+        if (_dev0.enumerating) {
+          TU_LOG_USBH("[%u:] USBH Defer Attach until current enumeration complete\r\n", event.rhport);
+
+          bool is_empty = osal_queue_empty(_usbh_q);
+          queue_event(&event, in_isr);
+
+          if (is_empty) {
+            // Exit if this is the only event in the queue, otherwise we may loop forever
+            return;
+          }
+        } else {
+          TU_LOG_USBH("[%u:] USBH DEVICE ATTACH\r\n", event.rhport);
+          _dev0.enumerating = 1;
+          enum_new_device(&event);
+        }
+        break;
 
       case HCD_EVENT_DEVICE_REMOVE:
-        TU_LOG2("USBH DEVICE REMOVED\r\n");
-        process_device_unplugged(event.rhport, event.connection.hub_addr, event.connection.hub_port);
+        TU_LOG_USBH("[%u:%u:%u] USBH DEVICE REMOVED\r\n", event.rhport, event.connection.hub_addr, event.connection.hub_port);
+        process_removing_device(event.rhport, event.connection.hub_addr, event.connection.hub_port);
 
         #if CFG_TUH_HUB
         // TODO remove
-        if ( event.connection.hub_addr != 0)
-        {
+        if (event.connection.hub_addr != 0 && event.connection.hub_port != 0) {
           // done with hub, waiting for next data on status pipe
-          (void) hub_status_pipe_queue( event.connection.hub_addr );
+          (void) hub_edpt_status_xfer(event.connection.hub_addr);
         }
         #endif
-      break;
+        break;
 
-      case HCD_EVENT_XFER_COMPLETE:
-      {
-        usbh_device_t* dev = &_usbh_devices[event.dev_addr];
+      case HCD_EVENT_XFER_COMPLETE: {
         uint8_t const ep_addr = event.xfer_complete.ep_addr;
-        uint8_t const epnum   = tu_edpt_number(ep_addr);
-        uint8_t const ep_dir  = tu_edpt_dir(ep_addr);
+        uint8_t const epnum = tu_edpt_number(ep_addr);
+        uint8_t const ep_dir = (uint8_t) tu_edpt_dir(ep_addr);
 
-        TU_LOG2("on EP %02X with %u bytes\r\n", ep_addr, (unsigned int) event.xfer_complete.len);
+        TU_LOG_USBH("on EP %02X with %u bytes: %s\r\n", ep_addr, (unsigned int) event.xfer_complete.len, tu_str_xfer_result[event.xfer_complete.result]);
 
-        dev->ep_status[epnum][ep_dir].busy = false;
-        dev->ep_status[epnum][ep_dir].claimed = 0;
+        if (event.dev_addr == 0) {
+          // device 0 only has control endpoint
+          TU_ASSERT(epnum == 0,);
+          usbh_control_xfer_cb(event.dev_addr, ep_addr, (xfer_result_t) event.xfer_complete.result, event.xfer_complete.len);
+        } else {
+          usbh_device_t* dev = get_device(event.dev_addr);
+          TU_VERIFY(dev && dev->connected,);
 
-        if ( 0 == epnum )
-        {
-          usbh_control_xfer_cb(event.dev_addr, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
-        }else
-        {
-          uint8_t drv_id = dev->ep2drv[epnum][ep_dir];
-          TU_ASSERT(drv_id < USBH_CLASS_DRIVER_COUNT, );
+          dev->ep_status[epnum][ep_dir].busy = 0;
+          dev->ep_status[epnum][ep_dir].claimed = 0;
 
-          TU_LOG2("%s xfer callback\r\n", usbh_class_drivers[drv_id].name);
-          usbh_class_drivers[drv_id].xfer_cb(event.dev_addr, ep_addr, event.xfer_complete.result, event.xfer_complete.len);
+          if (0 == epnum) {
+            usbh_control_xfer_cb(event.dev_addr, ep_addr, (xfer_result_t) event.xfer_complete.result, event.xfer_complete.len);
+          } else {
+            // Prefer application callback over built-in one if available. This occurs when tuh_edpt_xfer() is used
+            // with enabled driver e.g HID endpoint
+            #if CFG_TUH_API_EDPT_XFER
+            tuh_xfer_cb_t const complete_cb = dev->ep_callback[epnum][ep_dir].complete_cb;
+            if ( complete_cb ) {
+              // re-construct xfer info
+              tuh_xfer_t xfer = {
+                  .daddr       = event.dev_addr,
+                  .ep_addr     = ep_addr,
+                  .result      = event.xfer_complete.result,
+                  .actual_len  = event.xfer_complete.len,
+                  .buflen      = 0,    // not available
+                  .buffer      = NULL, // not available
+                  .complete_cb = complete_cb,
+                  .user_data   = dev->ep_callback[epnum][ep_dir].user_data
+              };
+              complete_cb(&xfer);
+            }else
+            #endif
+            {
+              uint8_t drv_id = dev->ep2drv[epnum][ep_dir];
+              usbh_class_driver_t const* driver = get_driver(drv_id);
+              if (driver) {
+                TU_LOG_USBH("%s xfer callback\r\n", driver->name);
+                driver->xfer_cb(event.dev_addr, ep_addr, (xfer_result_t) event.xfer_complete.result,
+                                event.xfer_complete.len);
+              } else {
+                // no driver/callback responsible for this transfer
+                TU_ASSERT(false,);
+              }
+            }
+          }
         }
+        break;
       }
-      break;
 
       case USBH_EVENT_FUNC_CALL:
-        if ( event.func_call.func ) event.func_call.func(event.func_call.param);
-      break;
+        if (event.func_call.func) event.func_call.func(event.func_call.param);
+        break;
 
-      default: break;
+      default:
+        break;
     }
+
+#if CFG_TUSB_OS != OPT_OS_NONE && CFG_TUSB_OS != OPT_OS_PICO
+    // return if there is no more events, for application to run other background
+    if (osal_queue_empty(_usbh_q)) return;
+#endif
   }
 }
 
 //--------------------------------------------------------------------+
-// USBH API For Class Driver
+// Control transfer
 //--------------------------------------------------------------------+
 
-uint8_t usbh_get_rhport(uint8_t dev_addr)
-{
-  return _usbh_devices[dev_addr].rhport;
-}
-
-uint8_t* usbh_get_enum_buf(void)
-{
-  return _usbh_ctrl_buf;
+static void _control_blocking_complete_cb(tuh_xfer_t* xfer) {
+  // update result
+  *((xfer_result_t*) xfer->user_data) = xfer->result;
 }
 
-//------------- Endpoint API -------------//
+// TODO timeout_ms is not supported yet
+bool tuh_control_xfer (tuh_xfer_t* xfer) {
+  // EP0 with setup packet
+  TU_VERIFY(xfer->ep_addr == 0 && xfer->setup);
 
-bool usbh_edpt_claim(uint8_t dev_addr, uint8_t ep_addr)
-{
-  uint8_t const epnum = tu_edpt_number(ep_addr);
-  uint8_t const dir   = tu_edpt_dir(ep_addr);
-
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
+  // Check if device is still connected (enumerating for dev0)
+  uint8_t const daddr = xfer->daddr;
+  if ( daddr == 0 ) {
+    if (!_dev0.enumerating) return false;
+  } else {
+    usbh_device_t const* dev = get_device(daddr);
+    if (dev && dev->connected == 0) return false;
+  }
 
-#if CFG_TUSB_OS != OPT_OS_NONE
   // pre-check to help reducing mutex lock
-  TU_VERIFY((dev->ep_status[epnum][dir].busy == 0) && (dev->ep_status[epnum][dir].claimed == 0));
-  osal_mutex_lock(dev->mutex, OSAL_TIMEOUT_WAIT_FOREVER);
-#endif
+  TU_VERIFY(_ctrl_xfer.stage == CONTROL_STAGE_IDLE);
+  (void) osal_mutex_lock(_usbh_mutex, OSAL_TIMEOUT_WAIT_FOREVER);
 
-  // can only claim the endpoint if it is not busy and not claimed yet.
-  bool const ret = (dev->ep_status[epnum][dir].busy == 0) && (dev->ep_status[epnum][dir].claimed == 0);
-  if (ret)
-  {
-    dev->ep_status[epnum][dir].claimed = 1;
+  bool const is_idle = (_ctrl_xfer.stage == CONTROL_STAGE_IDLE);
+  if (is_idle) {
+    _ctrl_xfer.stage       = CONTROL_STAGE_SETUP;
+    _ctrl_xfer.daddr       = daddr;
+    _ctrl_xfer.actual_len  = 0;
+
+    _ctrl_xfer.request     = (*xfer->setup);
+    _ctrl_xfer.buffer      = xfer->buffer;
+    _ctrl_xfer.complete_cb = xfer->complete_cb;
+    _ctrl_xfer.user_data   = xfer->user_data;
   }
 
-#if CFG_TUSB_OS != OPT_OS_NONE
-  osal_mutex_unlock(dev->mutex);
-#endif
+  (void) osal_mutex_unlock(_usbh_mutex);
 
-  return ret;
-}
+  TU_VERIFY(is_idle);
+  const uint8_t rhport = usbh_get_rhport(daddr);
 
-bool usbh_edpt_release(uint8_t dev_addr, uint8_t ep_addr)
-{
-  uint8_t const epnum = tu_edpt_number(ep_addr);
-  uint8_t const dir   = tu_edpt_dir(ep_addr);
+  TU_LOG_USBH("[%u:%u] %s: ", rhport, daddr,
+              (xfer->setup->bmRequestType_bit.type == TUSB_REQ_TYPE_STANDARD && xfer->setup->bRequest <= TUSB_REQ_SYNCH_FRAME) ?
+                  tu_str_std_request[xfer->setup->bRequest] : "Class Request");
+  TU_LOG_BUF_USBH(xfer->setup, 8);
 
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
+  if (xfer->complete_cb) {
+    TU_ASSERT( hcd_setup_send(rhport, daddr, (uint8_t const*) &_ctrl_xfer.request) );
+  }else {
+    // blocking if complete callback is not provided
+    // change callback to internal blocking, and result as user argument
+    volatile xfer_result_t result = XFER_RESULT_INVALID;
 
-#if CFG_TUSB_OS != OPT_OS_NONE
-  osal_mutex_lock(dev->mutex, OSAL_TIMEOUT_WAIT_FOREVER);
-#endif
+    // use user_data to point to xfer_result_t
+    _ctrl_xfer.user_data   = (uintptr_t) &result;
+    _ctrl_xfer.complete_cb = _control_blocking_complete_cb;
 
-  // can only release the endpoint if it is claimed and not busy
-  bool const ret = (dev->ep_status[epnum][dir].busy == 0) && (dev->ep_status[epnum][dir].claimed == 1);
-  if (ret)
-  {
-    dev->ep_status[epnum][dir].claimed = 0;
-  }
+    TU_ASSERT( hcd_setup_send(rhport, daddr, (uint8_t*) &_ctrl_xfer.request) );
 
-#if CFG_TUSB_OS != OPT_OS_NONE
-  osal_mutex_unlock(dev->mutex);
-#endif
+    while (result == XFER_RESULT_INVALID) {
+      // Note: this can be called within an callback ie. part of tuh_task()
+      // therefore event with RTOS tuh_task() still need to be invoked
+      if (tuh_task_event_ready()) {
+        tuh_task();
+      }
+      // TODO probably some timeout to prevent hanged
+    }
+
+    // update transfer result, user_data is expected to point to xfer_result_t
+    if (xfer->user_data != 0) {
+      *((xfer_result_t*) xfer->user_data) = result;
+    }
+    xfer->result     = result;
+    xfer->actual_len = _ctrl_xfer.actual_len;
+  }
 
-  return ret;
+  return true;
 }
 
-bool usbh_edpt_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes)
-{
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
-  TU_LOG2("  Queue EP %02X with %u bytes ... OK\r\n", ep_addr, total_bytes);
-  return hcd_edpt_xfer(dev->rhport, dev_addr, ep_addr, buffer, total_bytes);
+TU_ATTR_ALWAYS_INLINE static inline void _set_control_xfer_stage(uint8_t stage) {
+  (void) osal_mutex_lock(_usbh_mutex, OSAL_TIMEOUT_WAIT_FOREVER);
+  _ctrl_xfer.stage = stage;
+  (void) osal_mutex_unlock(_usbh_mutex);
 }
 
-bool usbh_edpt_control_open(uint8_t dev_addr, uint8_t max_packet_size)
-{
-  TU_LOG2("Open EP Control with Size = %u\r\n", max_packet_size);
+static void _control_xfer_complete(uint8_t daddr, xfer_result_t result) {
+  TU_LOG_USBH("\r\n");
 
-  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
+  // duplicate xfer since user can execute control transfer within callback
+  tusb_control_request_t const request = _ctrl_xfer.request;
+  tuh_xfer_t xfer_temp = {
+    .daddr       = daddr,
+    .ep_addr     = 0,
+    .result      = result,
+    .setup       = &request,
+    .actual_len  = (uint32_t) _ctrl_xfer.actual_len,
+    .buffer      = _ctrl_xfer.buffer,
+    .complete_cb = _ctrl_xfer.complete_cb,
+    .user_data   = _ctrl_xfer.user_data
   };
 
-  return hcd_edpt_open(_usbh_devices[dev_addr].rhport, dev_addr, &ep0_desc);
+  _set_control_xfer_stage(CONTROL_STAGE_IDLE);
+
+  if (xfer_temp.complete_cb) {
+    xfer_temp.complete_cb(&xfer_temp);
+  }
 }
 
-bool usbh_edpt_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_endpoint_t const * desc_ep)
-{
-  TU_LOG2("  Open EP %02X with Size = %u\r\n", desc_ep->bEndpointAddress, desc_ep->wMaxPacketSize.size);
+static bool usbh_control_xfer_cb (uint8_t daddr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes) {
+  (void) ep_addr;
 
-  bool ret = hcd_edpt_open(rhport, dev_addr, desc_ep);
+  const uint8_t rhport = usbh_get_rhport(daddr);
+  tusb_control_request_t const * request = &_ctrl_xfer.request;
 
-  if (ret)
-  {
-    usbh_device_t* dev = &_usbh_devices[dev_addr];
+  if (XFER_RESULT_SUCCESS != result) {
+    TU_LOG_USBH("[%u:%u] Control %s, xferred_bytes = %" PRIu32 "\r\n", rhport, daddr, result == XFER_RESULT_STALLED ? "STALLED" : "FAILED", xferred_bytes);
+    TU_LOG_BUF_USBH(request, 8);
 
-    // new endpoints belongs to latest interface (last valid value)
-    // TODO FIXME not true with ISO
-    uint8_t drvid = 0xff;
-    for(uint8_t i=0; i < sizeof(dev->itf2drv); i++)
-    {
-      if ( dev->itf2drv[i] == 0xff ) break;
-      drvid = dev->itf2drv[i];
+    // terminate transfer if any stage failed
+    _control_xfer_complete(daddr, result);
+  }else {
+    switch(_ctrl_xfer.stage) {
+      case CONTROL_STAGE_SETUP:
+        if (request->wLength) {
+          // DATA stage: initial data toggle is always 1
+          _set_control_xfer_stage(CONTROL_STAGE_DATA);
+          TU_ASSERT( hcd_edpt_xfer(rhport, daddr, tu_edpt_addr(0, request->bmRequestType_bit.direction), _ctrl_xfer.buffer, request->wLength) );
+          return true;
+        }
+        TU_ATTR_FALLTHROUGH;
+
+      case CONTROL_STAGE_DATA:
+        if (request->wLength) {
+          TU_LOG_USBH("[%u:%u] Control data:\r\n", rhport, daddr);
+          TU_LOG_MEM_USBH(_ctrl_xfer.buffer, xferred_bytes, 2);
+        }
+
+        _ctrl_xfer.actual_len = (uint16_t) xferred_bytes;
+
+        // ACK stage: toggle is always 1
+        _set_control_xfer_stage(CONTROL_STAGE_ACK);
+        TU_ASSERT( hcd_edpt_xfer(rhport, daddr, tu_edpt_addr(0, 1 - request->bmRequestType_bit.direction), NULL, 0) );
+        break;
+
+      case CONTROL_STAGE_ACK: {
+        // Abort all pending transfers if SET_CONFIGURATION request
+        // NOTE: should we force closing all non-control endpoints in the future?
+        if (request->bRequest == TUSB_REQ_SET_CONFIGURATION && request->bmRequestType == 0x00) {
+          for(uint8_t epnum=1; epnum<CFG_TUH_ENDPOINT_MAX; epnum++) {
+            for(uint8_t dir=0; dir<2; dir++) {
+              tuh_edpt_abort_xfer(daddr, tu_edpt_addr(epnum, dir));
+            }
+          }
+        }
+
+        _control_xfer_complete(daddr, result);
+        break;
+      }
+
+      default: return false;
     }
-    TU_ASSERT(drvid < USBH_CLASS_DRIVER_COUNT);
+  }
+
+  return true;
+}
 
-    uint8_t const ep_addr = desc_ep->bEndpointAddress;
-    dev->ep2drv[tu_edpt_number(ep_addr)][tu_edpt_dir(ep_addr)] = drvid;
+//--------------------------------------------------------------------+
+//
+//--------------------------------------------------------------------+
+
+bool tuh_edpt_xfer(tuh_xfer_t* xfer) {
+  uint8_t const daddr = xfer->daddr;
+  uint8_t const ep_addr = xfer->ep_addr;
+
+  TU_VERIFY(daddr && ep_addr);
+  TU_VERIFY(usbh_edpt_claim(daddr, ep_addr));
+
+  if (!usbh_edpt_xfer_with_callback(daddr, ep_addr, xfer->buffer, (uint16_t) xfer->buflen,
+                                    xfer->complete_cb, xfer->user_data)) {
+    usbh_edpt_release(daddr, ep_addr);
+    return false;
   }
 
-  return ret;
+  return true;
+}
+
+bool tuh_edpt_abort_xfer(uint8_t daddr, uint8_t ep_addr) {
+  usbh_device_t* dev = get_device(daddr);
+  TU_VERIFY(dev);
+
+  TU_LOG_USBH("[%u] Aborted transfer on EP %02X\r\n", daddr, ep_addr);
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir   = tu_edpt_dir(ep_addr);
+
+  if ( epnum == 0 ) {
+    // control transfer: only 1 control at a time, check if we are aborting the current one
+    TU_VERIFY(daddr == _ctrl_xfer.daddr && _ctrl_xfer.stage != CONTROL_STAGE_IDLE);
+    TU_VERIFY(hcd_edpt_abort_xfer(dev->rhport, daddr, ep_addr));
+    // reset control transfer state to idle
+    _set_control_xfer_stage(CONTROL_STAGE_IDLE);
+  } else {
+    // non-control skip if not busy
+    TU_VERIFY(dev->ep_status[epnum][dir].busy);
+    TU_VERIFY(hcd_edpt_abort_xfer(dev->rhport, daddr, ep_addr));
+    // mark as ready and release endpoint if transfer is aborted
+    dev->ep_status[epnum][dir].busy = false;
+    tu_edpt_release(&dev->ep_status[epnum][dir], _usbh_mutex);
+  }
+
+  return true;
 }
 
 //--------------------------------------------------------------------+
-// HCD Event Handler
+// USBH API For Class Driver
 //--------------------------------------------------------------------+
 
-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;
+uint8_t usbh_get_rhport(uint8_t dev_addr) {
+  usbh_device_t *dev = get_device(dev_addr);
+  return dev ? dev->rhport : _dev0.rhport;
+}
+
+uint8_t *usbh_get_enum_buf(void) {
+  return _usbh_ctrl_buf;
+}
+
+void usbh_int_set(bool enabled) {
+  // TODO all host controller if multiple are used since they shared the same event queue
+  if (enabled) {
+    hcd_int_enable(_usbh_controller);
+  } else {
+    hcd_int_disable(_usbh_controller);
   }
 }
 
-// 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, uint32_t xferred_bytes, xfer_result_t result, bool in_isr)
-{
-  hcd_event_t event =
-  {
-    .rhport   = 0, // TODO correct rhport
-    .event_id = HCD_EVENT_XFER_COMPLETE,
-    .dev_addr = dev_addr,
-    .xfer_complete =
-    {
-      .ep_addr = ep_addr,
-      .result  = result,
-      .len     = xferred_bytes
-    }
-  };
+void usbh_defer_func(osal_task_func_t func, void *param, bool in_isr) {
+  hcd_event_t event = { 0 };
+  event.event_id = USBH_EVENT_FUNC_CALL;
+  event.func_call.func = func;
+  event.func_call.param = param;
 
-  hcd_event_handler(&event, in_isr);
+  queue_event(&event, in_isr);
 }
 
-void hcd_event_device_attach(uint8_t rhport, bool in_isr)
-{
-  hcd_event_t event =
-  {
-    .rhport   = rhport,
-    .event_id = HCD_EVENT_DEVICE_ATTACH
-  };
+//--------------------------------------------------------------------+
+// Endpoint API
+//--------------------------------------------------------------------+
+
+// Claim an endpoint for transfer
+bool usbh_edpt_claim(uint8_t dev_addr, uint8_t ep_addr) {
+  // Note: addr0 only use tuh_control_xfer
+  usbh_device_t* dev = get_device(dev_addr);
+  TU_ASSERT(dev && dev->connected);
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir = tu_edpt_dir(ep_addr);
 
-  event.connection.hub_addr = 0;
-  event.connection.hub_port = 0;
+  TU_VERIFY(tu_edpt_claim(&dev->ep_status[epnum][dir], _usbh_mutex));
+  TU_LOG_USBH("[%u] Claimed EP 0x%02x\r\n", dev_addr, ep_addr);
 
-  hcd_event_handler(&event, in_isr);
+  return true;
 }
 
-void hcd_event_device_remove(uint8_t hostid, bool in_isr)
-{
-  hcd_event_t event =
-  {
-    .rhport   = hostid,
-    .event_id = HCD_EVENT_DEVICE_REMOVE
-  };
+// Release an claimed endpoint due to failed transfer attempt
+bool usbh_edpt_release(uint8_t dev_addr, uint8_t ep_addr) {
+  // Note: addr0 only use tuh_control_xfer
+  usbh_device_t* dev = get_device(dev_addr);
+  TU_VERIFY(dev && dev->connected);
 
-  event.connection.hub_addr = 0;
-  event.connection.hub_port = 0;
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir = tu_edpt_dir(ep_addr);
 
-  hcd_event_handler(&event, in_isr);
+  TU_VERIFY(tu_edpt_release(&dev->ep_status[epnum][dir], _usbh_mutex));
+  TU_LOG_USBH("[%u] Released EP 0x%02x\r\n", dev_addr, ep_addr);
+
+  return true;
 }
 
+// Submit an transfer
+// TODO call usbh_edpt_release if failed
+bool usbh_edpt_xfer_with_callback(uint8_t dev_addr, uint8_t ep_addr, uint8_t* buffer, uint16_t total_bytes,
+                                  tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  (void) complete_cb;
+  (void) user_data;
 
-// a device unplugged on hostid, hub_addr, hub_port
-// return true if found and unmounted device, false if cannot find
-void process_device_unplugged(uint8_t rhport, uint8_t hub_addr, uint8_t hub_port)
-{
-  //------------- 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];
+  usbh_device_t* dev = get_device(dev_addr);
+  TU_VERIFY(dev);
 
-    // TODO Hub multiple level
-    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);
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir = tu_edpt_dir(ep_addr);
+  tu_edpt_state_t* ep_state = &dev->ep_status[epnum][dir];
 
-      // Close class driver
-      for (uint8_t drv_id = 0; drv_id < USBH_CLASS_DRIVER_COUNT; drv_id++)
-      {
-        TU_LOG2("%s close\r\n", usbh_class_drivers[drv_id].name);
-        usbh_class_drivers[drv_id].close(dev_addr);
-      }
+  TU_LOG_USBH("  Queue EP %02X with %u bytes ... \r\n", ep_addr, total_bytes);
 
-      memset(dev->itf2drv, 0xff, sizeof(dev->itf2drv)); // invalid mapping
-      memset(dev->ep2drv , 0xff, sizeof(dev->ep2drv )); // invalid mapping
+  // Attempt to transfer on a busy endpoint, sound like an race condition !
+  TU_ASSERT(ep_state->busy == 0);
 
-      hcd_device_close(rhport, dev_addr);
+  // Set busy first since the actual transfer can be complete before hcd_edpt_xfer()
+  // could return and USBH task can preempt and clear the busy
+  ep_state->busy = 1;
 
-      dev->state = TUSB_DEVICE_STATE_UNPLUG;
-    }
+#if CFG_TUH_API_EDPT_XFER
+  dev->ep_callback[epnum][dir].complete_cb = complete_cb;
+  dev->ep_callback[epnum][dir].user_data   = user_data;
+#endif
+
+  if (hcd_edpt_xfer(dev->rhport, dev_addr, ep_addr, buffer, total_bytes)) {
+    TU_LOG_USBH("OK\r\n");
+    return true;
+  } else {
+    // HCD error, mark endpoint as ready to allow next transfer
+    ep_state->busy = 0;
+    ep_state->claimed = 0;
+    TU_LOG1("Failed\r\n");
+//    TU_BREAKPOINT();
+    return false;
   }
 }
 
+static bool usbh_edpt_control_open(uint8_t dev_addr, uint8_t max_packet_size) {
+  TU_LOG_USBH("[%u:%u] Open EP0 with Size = %u\r\n", usbh_get_rhport(dev_addr), dev_addr, max_packet_size);
+  tusb_desc_endpoint_t ep0_desc = {
+    .bLength          = sizeof(tusb_desc_endpoint_t),
+    .bDescriptorType  = TUSB_DESC_ENDPOINT,
+    .bEndpointAddress = 0,
+    .bmAttributes     = { .xfer = TUSB_XFER_CONTROL },
+    .wMaxPacketSize   = max_packet_size,
+    .bInterval        = 0
+  };
+
+  return hcd_edpt_open(usbh_get_rhport(dev_addr), dev_addr, &ep0_desc);
+}
+
+bool tuh_edpt_open(uint8_t dev_addr, tusb_desc_endpoint_t const* desc_ep) {
+  TU_ASSERT(tu_edpt_validate(desc_ep, tuh_speed_get(dev_addr)));
+  return hcd_edpt_open(usbh_get_rhport(dev_addr), dev_addr, desc_ep);
+}
+
+bool usbh_edpt_busy(uint8_t dev_addr, uint8_t ep_addr) {
+  usbh_device_t* dev = get_device(dev_addr);
+  TU_VERIFY(dev);
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir = tu_edpt_dir(ep_addr);
+
+  return dev->ep_status[epnum][dir].busy;
+}
+
 //--------------------------------------------------------------------+
-// INTERNAL HELPER
+// HCD Event Handler
 //--------------------------------------------------------------------+
-static uint8_t get_new_address(void)
-{
-  for (uint8_t addr=1; addr <= CFG_TUSB_HOST_DEVICE_MAX; addr++)
-  {
-    if (_usbh_devices[addr].state == TUSB_DEVICE_STATE_UNPLUG) return addr;
+
+void hcd_devtree_get_info(uint8_t dev_addr, hcd_devtree_info_t* devtree_info) {
+  usbh_device_t const* dev = get_device(dev_addr);
+  if (dev) {
+    devtree_info->rhport = dev->rhport;
+    devtree_info->hub_addr = dev->hub_addr;
+    devtree_info->hub_port = dev->hub_port;
+    devtree_info->speed = dev->speed;
+  } else {
+    devtree_info->rhport = _dev0.rhport;
+    devtree_info->hub_addr = _dev0.hub_addr;
+    devtree_info->hub_port = _dev0.hub_port;
+    devtree_info->speed = _dev0.speed;
   }
-  return CFG_TUSB_HOST_DEVICE_MAX+1;
 }
 
-void usbh_driver_set_config_complete(uint8_t dev_addr, uint8_t itf_num)
-{
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
+TU_ATTR_FAST_FUNC void hcd_event_handler(hcd_event_t const* event, bool in_isr) {
+  switch (event->event_id) {
+    case HCD_EVENT_DEVICE_REMOVE:
+      // FIXME device remove from a hub need an HCD API for hcd to free up endpoint
+      // mark device as removing to prevent further xfer before the event is processed in usbh task
 
-  for(itf_num++; itf_num < sizeof(dev->itf2drv); itf_num++)
-  {
-    // continue with next valid interface
-    uint8_t const drv_id = dev->itf2drv[itf_num];
-    if (drv_id != 0xff)
-    {
-      usbh_class_driver_t const * driver = &usbh_class_drivers[drv_id];
-      TU_LOG2("%s set config: itf = %u\r\n", driver->name, itf_num);
-      driver->set_config(dev_addr, itf_num);
+      // Check if dev0 is removed
+      if ((event->rhport == _dev0.rhport) && (event->connection.hub_addr == _dev0.hub_addr) &&
+          (event->connection.hub_port == _dev0.hub_port)) {
+        _dev0.enumerating = 0;
+      }
       break;
-    }
-  }
 
-  // all interface are configured
-  if (itf_num == sizeof(dev->itf2drv))
-  {
-    // Invoke callback if available
-    if (tuh_mount_cb) tuh_mount_cb(dev_addr);
+    default: break;
   }
+
+  queue_event(event, in_isr);
 }
 
 //--------------------------------------------------------------------+
-// Enumeration Process
-// is a lengthy process with a seires of control transfer to configure
-// newly attached device. Each step is handled by a function in this
-// section
-// TODO due to the shared _usbh_ctrl_buf, we must complete enumerating
-// one device before enumerating another one.
+// Descriptors Async
 //--------------------------------------------------------------------+
 
-static bool enum_request_addr0_device_desc(void);
-static bool enum_request_set_addr(void);
+// generic helper to get a descriptor
+// if blocking, user_data is pointed to xfer_result
+static bool _get_descriptor(uint8_t daddr, uint8_t type, uint8_t index, uint16_t language_id, void* buffer, uint16_t len,
+                            tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  tusb_control_request_t const request = {
+    .bmRequestType_bit = {
+      .recipient = TUSB_REQ_RCPT_DEVICE,
+      .type      = TUSB_REQ_TYPE_STANDARD,
+      .direction = TUSB_DIR_IN
+    },
+    .bRequest = TUSB_REQ_GET_DESCRIPTOR,
+    .wValue   = tu_htole16( TU_U16(type, index) ),
+    .wIndex   = tu_htole16(language_id),
+    .wLength  = tu_htole16(len)
+  };
+  tuh_xfer_t xfer = {
+    .daddr       = daddr,
+    .ep_addr     = 0,
+    .setup       = &request,
+    .buffer      = buffer,
+    .complete_cb = complete_cb,
+    .user_data   = user_data
+  };
 
-static bool enum_get_addr0_device_desc_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool enum_set_address_complete           (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool enum_get_device_desc_complete       (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool enum_get_9byte_config_desc_complete (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool enum_get_config_desc_complete       (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool enum_set_config_complete            (uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
-static bool parse_configuration_descriptor      (uint8_t dev_addr, tusb_desc_configuration_t const* desc_cfg);
+  return tuh_control_xfer(&xfer);
+}
 
-static bool enum_hub_clear_reset0_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) dev_addr; (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
-  enum_request_addr0_device_desc();
-  return true;
+bool tuh_descriptor_get(uint8_t daddr, uint8_t type, uint8_t index, void* buffer, uint16_t len,
+                        tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return _get_descriptor(daddr, type, index, 0x0000, buffer, len, complete_cb, user_data);
 }
 
-static bool enum_hub_clear_reset1_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) dev_addr; (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
-  usbh_device_t* dev0 = &_usbh_devices[0];
+bool tuh_descriptor_get_device(uint8_t daddr, void* buffer, uint16_t len,
+                               tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  len = tu_min16(len, sizeof(tusb_desc_device_t));
+  return tuh_descriptor_get(daddr, TUSB_DESC_DEVICE, 0, buffer, len, complete_cb, user_data);
+}
 
-  enum_request_set_addr();
+bool tuh_descriptor_get_configuration(uint8_t daddr, uint8_t index, void* buffer, uint16_t len,
+                                      tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return tuh_descriptor_get(daddr, TUSB_DESC_CONFIGURATION, index, buffer, len, complete_cb, user_data);
+}
 
-  // done with hub, waiting for next data on status pipe
-  (void) hub_status_pipe_queue( dev0->hub_addr );
+//------------- String Descriptor -------------//
 
-  return true;
+bool tuh_descriptor_get_string(uint8_t daddr, uint8_t index, uint16_t language_id, void* buffer, uint16_t len,
+                               tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  return _get_descriptor(daddr, TUSB_DESC_STRING, index, language_id, buffer, len, complete_cb, user_data);
 }
 
-static bool enum_hub_get_status1_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
+// Get manufacturer string descriptor
+bool tuh_descriptor_get_manufacturer_string(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len,
+                                            tuh_xfer_cb_t complete_cb, uintptr_t user_data)
 {
-  (void) dev_addr; (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
-  usbh_device_t* dev0 = &_usbh_devices[0];
+  usbh_device_t const* dev = get_device(daddr);
+  TU_VERIFY(dev && dev->i_manufacturer);
+  return tuh_descriptor_get_string(daddr, dev->i_manufacturer, language_id, buffer, len, complete_cb, user_data);
+}
 
-  hub_port_status_response_t port_status;
-  memcpy(&port_status, _usbh_ctrl_buf, sizeof(hub_port_status_response_t));
+// Get product string descriptor
+bool tuh_descriptor_get_product_string(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len,
+                                       tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  usbh_device_t const* dev = get_device(daddr);
+  TU_VERIFY(dev && dev->i_product);
+  return tuh_descriptor_get_string(daddr, dev->i_product, language_id, buffer, len, complete_cb, user_data);
+}
 
-  // Acknowledge Port Reset Change if Reset Successful
-  if (port_status.change.reset)
-  {
-    TU_ASSERT( hub_port_clear_feature(dev0->hub_addr, dev0->hub_port, HUB_FEATURE_PORT_RESET_CHANGE, enum_hub_clear_reset1_complete) );
-  }
+// Get serial string descriptor
+bool tuh_descriptor_get_serial_string(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len,
+                                      tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  usbh_device_t const* dev = get_device(daddr);
+  TU_VERIFY(dev && dev->i_serial);
+  return tuh_descriptor_get_string(daddr, dev->i_serial, language_id, buffer, len, complete_cb, user_data);
+}
 
-  return true;
+// Get HID report descriptor
+// if blocking, user_data is pointed to xfer_result
+bool tuh_descriptor_get_hid_report(uint8_t daddr, uint8_t itf_num, uint8_t desc_type, uint8_t index, void* buffer, uint16_t len,
+                                   tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  TU_LOG_USBH("HID Get Report Descriptor\r\n");
+  tusb_control_request_t const request = {
+      .bmRequestType_bit = {
+          .recipient = TUSB_REQ_RCPT_INTERFACE,
+          .type      = TUSB_REQ_TYPE_STANDARD,
+          .direction = TUSB_DIR_IN
+      },
+      .bRequest = TUSB_REQ_GET_DESCRIPTOR,
+      .wValue   = tu_htole16(TU_U16(desc_type, index)),
+      .wIndex   = tu_htole16((uint16_t) itf_num),
+      .wLength  = len
+  };
+  tuh_xfer_t xfer = {
+      .daddr       = daddr,
+      .ep_addr     = 0,
+      .setup       = &request,
+      .buffer      = buffer,
+      .complete_cb = complete_cb,
+      .user_data   = user_data
+  };
+
+  return tuh_control_xfer(&xfer);
 }
 
-static bool enum_hub_get_status0_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) dev_addr; (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
-  usbh_device_t* dev0 = &_usbh_devices[0];
+bool tuh_configuration_set(uint8_t daddr, uint8_t config_num,
+                           tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  TU_LOG_USBH("Set Configuration = %d\r\n", config_num);
+  tusb_control_request_t const request = {
+      .bmRequestType_bit = {
+          .recipient = TUSB_REQ_RCPT_DEVICE,
+          .type      = TUSB_REQ_TYPE_STANDARD,
+          .direction = TUSB_DIR_OUT
+      },
+      .bRequest = TUSB_REQ_SET_CONFIGURATION,
+      .wValue   = tu_htole16(config_num),
+      .wIndex   = 0,
+      .wLength  = 0
+  };
+  tuh_xfer_t xfer = {
+      .daddr       = daddr,
+      .ep_addr     = 0,
+      .setup       = &request,
+      .buffer      = NULL,
+      .complete_cb = complete_cb,
+      .user_data   = user_data
+  };
 
-  hub_port_status_response_t port_status;
-  memcpy(&port_status, _usbh_ctrl_buf, sizeof(hub_port_status_response_t));
+  return tuh_control_xfer(&xfer);
+}
 
-  if ( !port_status.status.connection )
-  {
-    // device unplugged while delaying, nothing else to do, queue hub status
-    return hub_status_pipe_queue(dev_addr);
-  }
+bool tuh_interface_set(uint8_t daddr, uint8_t itf_num, uint8_t itf_alt,
+                       tuh_xfer_cb_t complete_cb, uintptr_t user_data) {
+  TU_LOG_USBH("Set Interface %u Alternate %u\r\n", itf_num, itf_alt);
+  tusb_control_request_t const request = {
+      .bmRequestType_bit = {
+          .recipient = TUSB_REQ_RCPT_DEVICE,
+          .type      = TUSB_REQ_TYPE_STANDARD,
+          .direction = TUSB_DIR_OUT
+      },
+      .bRequest = TUSB_REQ_SET_INTERFACE,
+      .wValue   = tu_htole16(itf_alt),
+      .wIndex   = tu_htole16(itf_num),
+      .wLength  = 0
+  };
+  tuh_xfer_t xfer = {
+      .daddr       = daddr,
+      .ep_addr     = 0,
+      .setup       = &request,
+      .buffer      = NULL,
+      .complete_cb = complete_cb,
+      .user_data   = user_data
+  };
 
-  dev0->speed = (port_status.status.high_speed) ? TUSB_SPEED_HIGH :
-                (port_status.status.low_speed ) ? TUSB_SPEED_LOW  : TUSB_SPEED_FULL;
+  return tuh_control_xfer(&xfer);
+}
 
-  // Acknowledge Port Reset Change
-  if (port_status.change.reset)
-  {
-    hub_port_clear_feature(dev0->hub_addr, dev0->hub_port, HUB_FEATURE_PORT_RESET_CHANGE, enum_hub_clear_reset0_complete);
-  }
+//--------------------------------------------------------------------+
+// Descriptor Sync
+//--------------------------------------------------------------------+
 
-  return true;
+#define _CONTROL_SYNC_API(_async_func, ...) \
+  xfer_result_t result = XFER_RESULT_INVALID;\
+  TU_VERIFY(_async_func(__VA_ARGS__, NULL, (uintptr_t) &result), XFER_RESULT_TIMEOUT); \
+  return (uint8_t) result
+
+uint8_t tuh_descriptor_get_sync(uint8_t daddr, uint8_t type, uint8_t index,
+                                void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get, daddr, type, index, buffer, len);
 }
 
+uint8_t tuh_descriptor_get_device_sync(uint8_t daddr, void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_device, daddr, buffer, len);
+}
 
-static bool enum_request_set_addr(void)
-{
-  // Set 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
+uint8_t tuh_descriptor_get_configuration_sync(uint8_t daddr, uint8_t index,
+                                              void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_configuration, daddr, index, buffer, len);
+}
 
-  TU_LOG2("Set Address = %d\r\n", new_addr);
+uint8_t tuh_descriptor_get_hid_report_sync(uint8_t daddr, uint8_t itf_num, uint8_t desc_type, uint8_t index,
+                                           void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_hid_report, daddr, itf_num, desc_type, index, buffer, len);
+}
 
-  usbh_device_t* dev0    = &_usbh_devices[0];
-  usbh_device_t* new_dev = &_usbh_devices[new_addr];
+uint8_t tuh_descriptor_get_string_sync(uint8_t daddr, uint8_t index, uint16_t language_id,
+                                       void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_string, daddr, index, language_id, buffer, len);
+}
 
-  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->connected       = 1;
-  new_dev->ep0_packet_size = ((tusb_desc_device_t*) _usbh_ctrl_buf)->bMaxPacketSize0;
+uint8_t tuh_descriptor_get_manufacturer_string_sync(uint8_t daddr, uint16_t language_id,
+                                                    void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_manufacturer_string, daddr, language_id, buffer, len);
+}
 
-  tusb_control_request_t const new_request =
-  {
-    .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
-  };
+uint8_t tuh_descriptor_get_product_string_sync(uint8_t daddr, uint16_t language_id,
+                                               void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_product_string, daddr, language_id, buffer, len);
+}
 
-  TU_ASSERT( tuh_control_xfer(0, &new_request, NULL, enum_set_address_complete) );
+uint8_t tuh_descriptor_get_serial_string_sync(uint8_t daddr, uint16_t language_id,
+                                              void* buffer, uint16_t len) {
+  _CONTROL_SYNC_API(tuh_descriptor_get_serial_string, daddr, language_id, buffer, len);
+}
 
-  return true;
+//--------------------------------------------------------------------+
+// Detaching
+//--------------------------------------------------------------------+
+
+TU_ATTR_ALWAYS_INLINE static inline bool is_hub_addr(uint8_t daddr) {
+  return (CFG_TUH_HUB > 0) && (daddr > CFG_TUH_DEVICE_MAX);
 }
 
-static bool enum_new_device(hcd_event_t* event)
-{
-  usbh_device_t* dev0 = &_usbh_devices[0];
-  dev0->rhport   = event->rhport; // TODO refractor integrate to device_pool
-  dev0->hub_addr = event->connection.hub_addr;
-  dev0->hub_port = event->connection.hub_port;
-  dev0->state    = TUSB_DEVICE_STATE_UNPLUG;
+//static void mark_removing_device_isr(uint8_t rhport, uint8_t hub_addr, uint8_t hub_port) {
+//  for (uint8_t dev_id = 0; dev_id < TOTAL_DEVICES; dev_id++) {
+//    usbh_device_t *dev = &_usbh_devices[dev_id];
+//    uint8_t const daddr = dev_id + 1;
+//
+//    // hub_addr = 0 means roothub, hub_port = 0 means all devices of downstream hub
+//    if (dev->rhport == rhport && dev->connected &&
+//        (hub_addr == 0 || dev->hub_addr == hub_addr) &&
+//        (hub_port == 0 || dev->hub_port == hub_port)) {
+//      if (is_hub_addr(daddr)) {
+//        // If the device itself is a usb hub, mark all downstream devices.
+//        // FIXME recursive calls
+//        mark_removing_device_isr(rhport, daddr, 0);
+//      }
+//
+//      dev->removing = 1;
+//    }
+//  }
+//}
 
-  //------------- connected/disconnected directly with roothub -------------//
-  if (dev0->hub_addr == 0)
-  {
-    // wait until device is stable TODO non blocking
-    osal_task_delay(RESET_DELAY);
+// a device unplugged from rhport:hub_addr:hub_port
+static void process_removing_device(uint8_t rhport, uint8_t hub_addr, uint8_t hub_port) {
+  //------------- find the all devices (star-network) under port that is unplugged -------------//
+  // TODO mark as disconnected in ISR, also handle dev0
+  uint32_t removing_hubs = 0;
+  do {
+    for (uint8_t dev_id = 0; dev_id < TOTAL_DEVICES; dev_id++) {
+      usbh_device_t* dev = &_usbh_devices[dev_id];
+      uint8_t const daddr = dev_id + 1;
 
-    // device unplugged while delaying
-    if ( !hcd_port_connect_status(dev0->rhport) ) return true;
+      // hub_addr = 0 means roothub, hub_port = 0 means all devices of downstream hub
+      if (dev->rhport == rhport && dev->connected &&
+          (hub_addr == 0 || dev->hub_addr == hub_addr) &&
+          (hub_port == 0 || dev->hub_port == hub_port)) {
+        TU_LOG_USBH("[%u:%u:%u] unplugged address = %u\r\n", rhport, hub_addr, hub_port, daddr);
 
-    dev0->speed = hcd_port_speed_get( dev0->rhport );
+        if (is_hub_addr(daddr)) {
+          TU_LOG_USBH("  is a HUB device %u\r\n", daddr);
+          removing_hubs |= TU_BIT(dev_id - CFG_TUH_DEVICE_MAX);
+        } else {
+          // Invoke callback before closing driver (maybe call it later ?)
+          if (tuh_umount_cb) tuh_umount_cb(daddr);
+        }
 
-    enum_request_addr0_device_desc();
-  }
-#if CFG_TUH_HUB
-  //------------- connected/disconnected via hub -------------//
-  else
-  {
-    // wait until device is stable
-    osal_task_delay(RESET_DELAY);
-    TU_ASSERT( hub_port_get_status(dev0->hub_addr, dev0->hub_port, _usbh_ctrl_buf, enum_hub_get_status0_complete) );
-  }
-#endif // CFG_TUH_HUB
+        // Close class driver
+        for (uint8_t drv_id = 0; drv_id < TOTAL_DRIVER_COUNT; drv_id++) {
+          usbh_class_driver_t const* driver = get_driver(drv_id);
+          if (driver) driver->close(daddr);
+        }
 
-  return true;
-}
+        hcd_device_close(rhport, daddr);
+        clear_device(dev);
 
-static bool enum_request_addr0_device_desc(void)
-{
-  // TODO probably doesn't need to open/close each enumeration
-  TU_ASSERT( usbh_edpt_control_open(0, 8) );
+        // abort on-going control xfer on this device if any
+        if (_ctrl_xfer.daddr == daddr) _set_control_xfer_stage(CONTROL_STAGE_IDLE);
+      }
+    }
 
-  //------------- Get first 8 bytes of device descriptor to get Control Endpoint Size -------------//
-  TU_LOG2("Get 8 byte of Device Descriptor\r\n");
-  tusb_control_request_t const request =
-  {
-    .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
-  };
-  TU_ASSERT( tuh_control_xfer(0, &request, _usbh_ctrl_buf, enum_get_addr0_device_desc_complete) );
+    // if removing a hub, we need to remove its downstream devices
+    #if CFG_TUH_HUB
+    if (removing_hubs == 0) break;
 
-  return true;
+    // find a marked hub to process
+    for (uint8_t h_id = 0; h_id < CFG_TUH_HUB; h_id++) {
+      if (tu_bit_test(removing_hubs, h_id)) {
+        removing_hubs &= ~TU_BIT(h_id);
+
+        // update hub_addr and hub_port for next loop
+        hub_addr = h_id + 1 + CFG_TUH_DEVICE_MAX;
+        hub_port = 0;
+        break;
+      }
+    }
+    #else
+    (void) removing_hubs;
+    break;
+    #endif
+  } while(1);
 }
 
-// After Get Device Descriptor of Address 0
-static bool enum_get_addr0_device_desc_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) request;
-  TU_ASSERT(0 == dev_addr);
+//--------------------------------------------------------------------+
+// Enumeration Process
+// is a lengthy process with a series of control transfer to configure
+// newly attached device.
+// NOTE: due to the shared _usbh_ctrl_buf, we must complete enumerating
+// one device before enumerating another one.
+//--------------------------------------------------------------------+
 
-  usbh_device_t* dev0 = &_usbh_devices[0];
+enum {
+  ENUM_RESET_DELAY = 50, // USB specs: 10 to 50ms
+  ENUM_CONTACT_DEBOUNCING_DELAY = 450, // when plug/unplug a device, physical connection can be bouncing and may
+                                       // generate a series of attach/detach event. This delay wait for stable connection
+};
 
-  if (XFER_RESULT_SUCCESS != result)
-  {
-#if CFG_TUH_HUB
-    // TODO remove, waiting for next data on status pipe
-    if (dev0->hub_addr != 0) hub_status_pipe_queue(dev0->hub_addr);
-#endif
+enum {
+  ENUM_IDLE,
+  ENUM_RESET_1,         // 1st reset when attached
+  //ENUM_HUB_GET_STATUS_1,
+  ENUM_HUB_CLEAR_RESET_1,
+  ENUM_ADDR0_DEVICE_DESC,
+  ENUM_RESET_2,         // 2nd reset before set address (not used)
+  ENUM_HUB_GET_STATUS_2,
+  ENUM_HUB_CLEAR_RESET_2,
+  ENUM_SET_ADDR,
 
-    return false;
-  }
+  ENUM_GET_DEVICE_DESC,
+  ENUM_GET_9BYTE_CONFIG_DESC,
+  ENUM_GET_FULL_CONFIG_DESC,
+  ENUM_SET_CONFIG,
+  ENUM_CONFIG_DRIVER
+};
 
-  // Reset device again before Set Address
-  TU_LOG2("Port reset \r\n");
+static bool enum_request_set_addr(void);
+static bool _parse_configuration_descriptor (uint8_t dev_addr, tusb_desc_configuration_t const* desc_cfg);
+static void enum_full_complete(void);
 
-  if (dev0->hub_addr == 0)
-  {
-    // connected directly to roothub
-    hcd_port_reset( dev0->rhport ); // reset port after 8 byte descriptor
-    osal_task_delay(RESET_DELAY);
+// process device enumeration
+static void process_enumeration(tuh_xfer_t* xfer) {
+  // Retry a few times with transfers in enumeration since device can be unstable when starting up
+  enum {
+    ATTEMPT_COUNT_MAX = 3,
+    ATTEMPT_DELAY_MS = 100
+  };
+  static uint8_t failed_count = 0;
 
-    enum_request_set_addr();
-  }
-#if CFG_TUH_HUB
-  else
-  {
-    // after RESET_DELAY the hub_port_reset() already complete
-    TU_ASSERT( hub_port_reset(dev0->hub_addr, dev0->hub_port, NULL) );
-    osal_task_delay(RESET_DELAY);
+  if (XFER_RESULT_SUCCESS != xfer->result) {
+    // retry if not reaching max attempt
+    bool retry = _dev0.enumerating && (failed_count < ATTEMPT_COUNT_MAX);
+    if ( retry ) {
+      failed_count++;
+      osal_task_delay(ATTEMPT_DELAY_MS); // delay a bit
+      TU_LOG1("Enumeration attempt %u\r\n", failed_count);
+      retry = tuh_control_xfer(xfer);
+    }
 
-    tuh_task(); // FIXME temporarily to clean up port_reset control transfer
+    if (!retry) {
+      enum_full_complete();
+    }
 
-    TU_ASSERT( hub_port_get_status(dev0->hub_addr, dev0->hub_port, _usbh_ctrl_buf, enum_hub_get_status1_complete) );
+    return;
   }
+  failed_count = 0;
+
+  uint8_t const daddr = xfer->daddr;
+  uintptr_t const state = xfer->user_data;
+
+  switch (state) {
+    #if CFG_TUH_HUB
+    //case ENUM_HUB_GET_STATUS_1: break;
+
+    case ENUM_HUB_CLEAR_RESET_1: {
+      hub_port_status_response_t port_status;
+      memcpy(&port_status, _usbh_ctrl_buf, sizeof(hub_port_status_response_t));
+
+      if (!port_status.status.connection) {
+        // device unplugged while delaying, nothing else to do
+        enum_full_complete();
+        return;
+      }
+
+      _dev0.speed = (port_status.status.high_speed) ? TUSB_SPEED_HIGH :
+                    (port_status.status.low_speed) ? TUSB_SPEED_LOW : TUSB_SPEED_FULL;
+
+      // Acknowledge Port Reset Change
+      if (port_status.change.reset) {
+        hub_port_clear_reset_change(_dev0.hub_addr, _dev0.hub_port,
+                                    process_enumeration, ENUM_ADDR0_DEVICE_DESC);
+      }
+      break;
+    }
+
+    case ENUM_HUB_GET_STATUS_2:
+      osal_task_delay(ENUM_RESET_DELAY);
+      TU_ASSERT(hub_port_get_status(_dev0.hub_addr, _dev0.hub_port, _usbh_ctrl_buf,
+                                    process_enumeration, ENUM_HUB_CLEAR_RESET_2),);
+      break;
+
+    case ENUM_HUB_CLEAR_RESET_2: {
+      hub_port_status_response_t port_status;
+      memcpy(&port_status, _usbh_ctrl_buf, sizeof(hub_port_status_response_t));
+
+      // Acknowledge Port Reset Change if Reset Successful
+      if (port_status.change.reset) {
+        TU_ASSERT(hub_port_clear_reset_change(_dev0.hub_addr, _dev0.hub_port,
+                                              process_enumeration, ENUM_SET_ADDR),);
+      }
+      break;
+    }
+    #endif
+
+    case ENUM_ADDR0_DEVICE_DESC: {
+      // TODO probably doesn't need to open/close each enumeration
+      uint8_t const addr0 = 0;
+      TU_ASSERT(usbh_edpt_control_open(addr0, 8),);
+
+      // Get first 8 bytes of device descriptor for Control Endpoint size
+      TU_LOG_USBH("Get 8 byte of Device Descriptor\r\n");
+      TU_ASSERT(tuh_descriptor_get_device(addr0, _usbh_ctrl_buf, 8,
+                                          process_enumeration, ENUM_SET_ADDR),);
+      break;
+    }
+
+#if 0
+      case ENUM_RESET_2:
+        // TODO not used by now, but may be needed for some devices !?
+        // Reset device again before Set Address
+        TU_LOG_USBH("Port reset2 \r\n");
+        if (_dev0.hub_addr == 0) {
+          // connected directly to roothub
+          hcd_port_reset( _dev0.rhport );
+          osal_task_delay(RESET_DELAY); // TODO may not work for no-OS on MCU that require reset_end() since
+                                        // sof of controller may not running while resetting
+          hcd_port_reset_end(_dev0.rhport);
+          // TODO: fall through to SET ADDRESS, refactor later
+        }
+#if CFG_TUH_HUB
+        else {
+          // after RESET_DELAY the hub_port_reset() already complete
+          TU_ASSERT( hub_port_reset(_dev0.hub_addr, _dev0.hub_port,
+                                    process_enumeration, ENUM_HUB_GET_STATUS_2), );
+          break;
+        }
+#endif
+        TU_ATTR_FALLTHROUGH;
 #endif
 
-  return true;
-}
+    case ENUM_SET_ADDR:
+      enum_request_set_addr();
+      break;
 
-// After SET_ADDRESS is complete
-static bool enum_set_address_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  TU_ASSERT(0 == dev_addr);
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
+    case ENUM_GET_DEVICE_DESC: {
+      uint8_t const new_addr = (uint8_t) tu_le16toh(xfer->setup->wValue);
 
-  uint8_t const new_addr = (uint8_t const) request->wValue;
+      usbh_device_t* new_dev = get_device(new_addr);
+      TU_ASSERT(new_dev,);
+      new_dev->addressed = 1;
 
-  usbh_device_t* new_dev = &_usbh_devices[new_addr];
-  new_dev->addressed = 1;
+      // Close device 0
+      hcd_device_close(_dev0.rhport, 0);
 
-  // TODO close device 0, may not be needed
-  usbh_device_t* dev0 = &_usbh_devices[0];
-  hcd_device_close(dev0->rhport, 0);
-  dev0->state = TUSB_DEVICE_STATE_UNPLUG;
+      // open control pipe for new address
+      TU_ASSERT(usbh_edpt_control_open(new_addr, new_dev->ep0_size),);
 
-  // open control pipe for new address
-  TU_ASSERT ( usbh_edpt_control_open(new_addr, new_dev->ep0_packet_size) );
+      // Get full device descriptor
+      TU_LOG_USBH("Get Device Descriptor\r\n");
+      TU_ASSERT(tuh_descriptor_get_device(new_addr, _usbh_ctrl_buf, sizeof(tusb_desc_device_t),
+                                          process_enumeration, ENUM_GET_9BYTE_CONFIG_DESC),);
+      break;
+    }
 
-  // Get full device descriptor
-  TU_LOG2("Get Device Descriptor\r\n");
-  tusb_control_request_t const new_request =
-  {
-    .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  = sizeof(tusb_desc_device_t)
-  };
+    case ENUM_GET_9BYTE_CONFIG_DESC: {
+      tusb_desc_device_t const* desc_device = (tusb_desc_device_t const*) _usbh_ctrl_buf;
+      usbh_device_t* dev = get_device(daddr);
+      TU_ASSERT(dev,);
 
-  TU_ASSERT(tuh_control_xfer(new_addr, &new_request, _usbh_ctrl_buf, enum_get_device_desc_complete));
+      dev->vid = desc_device->idVendor;
+      dev->pid = desc_device->idProduct;
+      dev->i_manufacturer = desc_device->iManufacturer;
+      dev->i_product = desc_device->iProduct;
+      dev->i_serial = desc_device->iSerialNumber;
 
-  return true;
-}
+      //  if (tuh_attach_cb) tuh_attach_cb((tusb_desc_device_t*) _usbh_ctrl_buf);
 
-static bool enum_get_device_desc_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
+      // Get 9-byte for total length
+      uint8_t const config_idx = CONFIG_NUM - 1;
+      TU_LOG_USBH("Get Configuration[0] Descriptor (9 bytes)\r\n");
+      TU_ASSERT(tuh_descriptor_get_configuration(daddr, config_idx, _usbh_ctrl_buf, 9,
+                                                 process_enumeration, ENUM_GET_FULL_CONFIG_DESC),);
+      break;
+    }
 
-  tusb_desc_device_t const * desc_device = (tusb_desc_device_t const*) _usbh_ctrl_buf;
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
+    case ENUM_GET_FULL_CONFIG_DESC: {
+      uint8_t const* desc_config = _usbh_ctrl_buf;
 
-  dev->vendor_id  = desc_device->idVendor;
-  dev->product_id = desc_device->idProduct;
+      // Use offsetof to avoid pointer to the odd/misaligned address
+      uint16_t const total_len = tu_le16toh(
+          tu_unaligned_read16(desc_config + offsetof(tusb_desc_configuration_t, wTotalLength)));
 
-//  if (tuh_attach_cb) tuh_attach_cb((tusb_desc_device_t*) _usbh_ctrl_buf);
+      // TODO not enough buffer to hold configuration descriptor
+      TU_ASSERT(total_len <= CFG_TUH_ENUMERATION_BUFSIZE,);
 
-  TU_LOG2("Get 9 bytes of Configuration Descriptor\r\n");
-  tusb_control_request_t const new_request =
-  {
-    .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) | (CONFIG_NUM - 1),
-    .wIndex   = 0,
-    .wLength  = 9
-  };
+      // Get full configuration descriptor
+      uint8_t const config_idx = CONFIG_NUM - 1;
+      TU_LOG_USBH("Get Configuration[0] Descriptor\r\n");
+      TU_ASSERT(tuh_descriptor_get_configuration(daddr, config_idx, _usbh_ctrl_buf, total_len,
+                                                 process_enumeration, ENUM_SET_CONFIG),);
+      break;
+    }
 
-  TU_ASSERT( tuh_control_xfer(dev_addr, &new_request, _usbh_ctrl_buf, enum_get_9byte_config_desc_complete) );
+    case ENUM_SET_CONFIG:
+      TU_ASSERT(tuh_configuration_set(daddr, CONFIG_NUM, process_enumeration, ENUM_CONFIG_DRIVER),);
+      break;
 
-  return true;
+    case ENUM_CONFIG_DRIVER: {
+      TU_LOG_USBH("Device configured\r\n");
+      usbh_device_t* dev = get_device(daddr);
+      TU_ASSERT(dev,);
+
+      dev->configured = 1;
+
+      // Parse configuration & set up drivers
+      // driver_open() must not make any usb transfer
+      TU_ASSERT(_parse_configuration_descriptor(daddr, (tusb_desc_configuration_t*) _usbh_ctrl_buf),);
+
+      // Start the Set Configuration process for interfaces (itf = TUSB_INDEX_INVALID_8)
+      // Since driver can perform control transfer within its set_config, this is done asynchronously.
+      // The process continue with next interface when class driver complete its sequence with usbh_driver_set_config_complete()
+      // TODO use separated API instead of using TUSB_INDEX_INVALID_8
+      usbh_driver_set_config_complete(daddr, TUSB_INDEX_INVALID_8);
+      break;
+    }
+
+    default:
+      // stop enumeration if unknown state
+      enum_full_complete();
+      break;
+  }
 }
 
-static bool enum_get_9byte_config_desc_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
+static bool enum_new_device(hcd_event_t* event) {
+  _dev0.rhport = event->rhport;
+  _dev0.hub_addr = event->connection.hub_addr;
+  _dev0.hub_port = event->connection.hub_port;
 
-  // TODO not enough buffer to hold configuration descriptor
-  tusb_desc_configuration_t const * desc_config = (tusb_desc_configuration_t const*) _usbh_ctrl_buf;
-  uint16_t total_len;
+  if (_dev0.hub_addr == 0) {
+    // connected/disconnected directly with roothub
+    hcd_port_reset(_dev0.rhport);
+    osal_task_delay(ENUM_RESET_DELAY); // TODO may not work for no-OS on MCU that require reset_end() since
+    // sof of controller may not running while resetting
+    hcd_port_reset_end(_dev0.rhport);
 
-  // Use offsetof to avoid pointer to the odd/misaligned address
-  memcpy(&total_len, (uint8_t*) desc_config + offsetof(tusb_desc_configuration_t, wTotalLength), 2);
+    // wait until device connection is stable TODO non blocking
+    osal_task_delay(ENUM_CONTACT_DEBOUNCING_DELAY);
 
-  TU_ASSERT(total_len <= CFG_TUH_ENUMERATION_BUFSZIE);
+    // device unplugged while delaying
+    if (!hcd_port_connect_status(_dev0.rhport)) {
+      enum_full_complete();
+      return true;
+    }
 
-  // Get full configuration descriptor
-  TU_LOG2("Get Configuration Descriptor\r\n");
-  tusb_control_request_t const new_request =
-  {
-    .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) | (CONFIG_NUM - 1),
-    .wIndex   = 0,
-    .wLength  = total_len
+    _dev0.speed = hcd_port_speed_get(_dev0.rhport);
+    TU_LOG_USBH("%s Speed\r\n", tu_str_speed[_dev0.speed]);
 
-  };
+    // fake transfer to kick-off the enumeration process
+    tuh_xfer_t xfer;
+    xfer.daddr = 0;
+    xfer.result = XFER_RESULT_SUCCESS;
+    xfer.user_data = ENUM_ADDR0_DEVICE_DESC;
 
-  TU_ASSERT( tuh_control_xfer(dev_addr, &new_request, _usbh_ctrl_buf, enum_get_config_desc_complete) );
+    process_enumeration(&xfer);
+  }
+#if CFG_TUH_HUB
+  else {
+    // connected/disconnected via external hub
+    // wait until device connection is stable TODO non blocking
+    osal_task_delay(ENUM_CONTACT_DEBOUNCING_DELAY);
+
+    // ENUM_HUB_GET_STATUS
+    //TU_ASSERT( hub_port_get_status(_dev0.hub_addr, _dev0.hub_port, _usbh_ctrl_buf, enum_hub_get_status0_complete, 0) );
+    TU_ASSERT(hub_port_get_status(_dev0.hub_addr, _dev0.hub_port, _usbh_ctrl_buf,
+                                  process_enumeration, ENUM_HUB_CLEAR_RESET_1));
+  }
+#endif // hub
 
   return true;
 }
 
-static bool enum_get_config_desc_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
-
-  // Parse configuration & set up drivers
-  // Driver open aren't allowed to make any usb transfer yet
-  parse_configuration_descriptor(dev_addr, (tusb_desc_configuration_t*) _usbh_ctrl_buf);
+static uint8_t get_new_address(bool is_hub) {
+  uint8_t start;
+  uint8_t end;
 
-  TU_LOG2("Set Configuration = %d\r\n", CONFIG_NUM);
-  tusb_control_request_t const new_request =
-  {
-    .bmRequestType_bit =
-    {
-      .recipient = TUSB_REQ_RCPT_DEVICE,
-      .type      = TUSB_REQ_TYPE_STANDARD,
-      .direction = TUSB_DIR_OUT
-    },
-    .bRequest = TUSB_REQ_SET_CONFIGURATION,
-    .wValue   = CONFIG_NUM,
-    .wIndex   = 0,
-    .wLength  = 0
-  };
+  if ( is_hub ) {
+    start = CFG_TUH_DEVICE_MAX;
+    end   = start + CFG_TUH_HUB;
+  }else {
+    start = 0;
+    end   = start + CFG_TUH_DEVICE_MAX;
+  }
 
-  TU_ASSERT( tuh_control_xfer(dev_addr, &new_request, NULL, enum_set_config_complete) );
+  for (uint8_t idx = start; idx < end; idx++) {
+    if (!_usbh_devices[idx].connected) return (idx+1);
+  }
 
-  return true;
+  return 0; // invalid address
 }
 
-static bool enum_set_config_complete(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result)
-{
-  (void) request;
-  TU_ASSERT(XFER_RESULT_SUCCESS == result);
+static bool enum_request_set_addr(void) {
+  tusb_desc_device_t const* desc_device = (tusb_desc_device_t const*) _usbh_ctrl_buf;
 
-  TU_LOG2("Device configured\r\n");
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
-  dev->configured = 1;
-  dev->state = TUSB_DEVICE_STATE_CONFIGURED;
+  // Get new address
+  uint8_t const new_addr = get_new_address(desc_device->bDeviceClass == TUSB_CLASS_HUB);
+  TU_ASSERT(new_addr != 0);
+  TU_LOG_USBH("Set Address = %d\r\n", new_addr);
 
-  // Start the Set Configuration process for interfaces (itf = 0xff)
-  // Since driver can perform control transfer within its set_config, this is done asynchronously.
-  // The process continue with next interface when class driver complete its sequence with usbh_driver_set_config_complete()
-  // TODO use separated API instead of usig 0xff
-  usbh_driver_set_config_complete(dev_addr, 0xff);
+  usbh_device_t* new_dev = get_device(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->connected = 1;
+  new_dev->ep0_size = desc_device->bMaxPacketSize0;
+
+  tusb_control_request_t const request = {
+      .bmRequestType_bit = {
+          .recipient = TUSB_REQ_RCPT_DEVICE,
+          .type      = TUSB_REQ_TYPE_STANDARD,
+          .direction = TUSB_DIR_OUT
+      },
+      .bRequest = TUSB_REQ_SET_ADDRESS,
+      .wValue   = tu_htole16(new_addr),
+      .wIndex   = 0,
+      .wLength  = 0
+  };
+  tuh_xfer_t xfer = {
+      .daddr       = 0, // dev0
+      .ep_addr     = 0,
+      .setup       = &request,
+      .buffer      = NULL,
+      .complete_cb = process_enumeration,
+      .user_data   = ENUM_GET_DEVICE_DESC
+  };
 
+  TU_ASSERT(tuh_control_xfer(&xfer));
   return true;
 }
 
-static bool parse_configuration_descriptor(uint8_t dev_addr, tusb_desc_configuration_t const* desc_cfg)
-{
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
-  uint8_t const* p_desc = (uint8_t const*) desc_cfg;
-  p_desc = tu_desc_next(p_desc);
+static bool _parse_configuration_descriptor(uint8_t dev_addr, tusb_desc_configuration_t const* desc_cfg) {
+  usbh_device_t* dev = get_device(dev_addr);
+  uint16_t const total_len = tu_le16toh(desc_cfg->wTotalLength);
+  uint8_t const* desc_end = ((uint8_t const*) desc_cfg) + total_len;
+  uint8_t const* p_desc   = tu_desc_next(desc_cfg);
+
+  TU_LOG_USBH("Parsing Configuration descriptor (wTotalLength = %u)\r\n", total_len);
 
   // parse each interfaces
-  while( p_desc < _usbh_ctrl_buf + desc_cfg->wTotalLength )
-  {
-    // skip until we see interface descriptor
-    if ( TUSB_DESC_INTERFACE != tu_desc_type(p_desc) )
-    {
-      p_desc = tu_desc_next(p_desc); // skip the descriptor, increase by the descriptor's length
-    }else
-    {
-      tusb_desc_interface_t const* desc_itf = (tusb_desc_interface_t const*) p_desc;
+  while( p_desc < desc_end ) {
+    uint8_t assoc_itf_count = 1;
 
-      // 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;
-      }
+    // Class will always starts with Interface Association (if any) and then Interface descriptor
+    if ( TUSB_DESC_INTERFACE_ASSOCIATION == tu_desc_type(p_desc) ) {
+      tusb_desc_interface_assoc_t const * desc_iad = (tusb_desc_interface_assoc_t const *) p_desc;
+      assoc_itf_count = desc_iad->bInterfaceCount;
 
-      if( drv_id >= USBH_CLASS_DRIVER_COUNT )
-      {
-        // skip unsupported class
-        p_desc = tu_desc_next(p_desc);
-      }
-      else
-      {
-        usbh_class_driver_t const * driver = &usbh_class_drivers[drv_id];
+      p_desc = tu_desc_next(p_desc); // next to Interface
+
+      // IAD's first interface number and class should match with opened interface
+      //TU_ASSERT(desc_iad->bFirstInterface == desc_itf->bInterfaceNumber &&
+      //          desc_iad->bFunctionClass  == desc_itf->bInterfaceClass);
+    }
 
-        // Interface number must not be used already TODO alternate interface
-        TU_ASSERT( dev->itf2drv[desc_itf->bInterfaceNumber] == 0xff );
-        dev->itf2drv[desc_itf->bInterfaceNumber] = drv_id;
+    TU_ASSERT( TUSB_DESC_INTERFACE == tu_desc_type(p_desc) );
+    tusb_desc_interface_t const* desc_itf = (tusb_desc_interface_t const*) p_desc;
 
-        if (desc_itf->bInterfaceClass == TUSB_CLASS_HUB && dev->hub_addr != 0)
-        {
-          // TODO Attach hub to Hub is not currently supported
-          // skip this interface
-          p_desc = tu_desc_next(p_desc);
-        }
-        else
-        {
-          TU_LOG2("%s open\r\n", driver->name);
+#if CFG_TUH_MIDI
+    // MIDI has 2 interfaces (Audio Control v1 + MIDIStreaming) but does not have IAD
+    // manually force associated count = 2
+    if (1                              == assoc_itf_count              &&
+        TUSB_CLASS_AUDIO               == desc_itf->bInterfaceClass    &&
+        AUDIO_SUBCLASS_CONTROL         == desc_itf->bInterfaceSubClass &&
+        AUDIO_FUNC_PROTOCOL_CODE_UNDEF == desc_itf->bInterfaceProtocol) {
+      assoc_itf_count = 2;
+    }
+#endif
+
+#if CFG_TUH_CDC
+    // Some legacy CDC device does not use IAD but rather use device class as hint to combine 2 interfaces
+    // manually force associated count = 2
+    if (1                                        == assoc_itf_count              &&
+        TUSB_CLASS_CDC                           == desc_itf->bInterfaceClass    &&
+        CDC_COMM_SUBCLASS_ABSTRACT_CONTROL_MODEL == desc_itf->bInterfaceSubClass) {
+      assoc_itf_count = 2;
+    }
+#endif
+
+    uint16_t const drv_len = tu_desc_get_interface_total_len(desc_itf, assoc_itf_count, (uint16_t) (desc_end-p_desc));
+    TU_ASSERT(drv_len >= sizeof(tusb_desc_interface_t));
+
+    // Find driver for this interface
+    for (uint8_t drv_id = 0; drv_id < TOTAL_DRIVER_COUNT; drv_id++) {
+      usbh_class_driver_t const * driver = get_driver(drv_id);
+      if (driver && driver->open(dev->rhport, dev_addr, desc_itf, drv_len) ) {
+        // open successfully
+        TU_LOG_USBH("  %s opened\r\n", driver->name);
 
-          uint16_t itf_len = 0;
-          TU_ASSERT( driver->open(dev->rhport, dev_addr, desc_itf, &itf_len) );
-          TU_ASSERT( itf_len >= sizeof(tusb_desc_interface_t) );
-          p_desc += itf_len;
+        // bind (associated) interfaces to found driver
+        for(uint8_t i=0; i<assoc_itf_count; i++) {
+          uint8_t const itf_num = desc_itf->bInterfaceNumber+i;
+
+          // Interface number must not be used already
+          TU_ASSERT( TUSB_INDEX_INVALID_8 == dev->itf2drv[itf_num] );
+          dev->itf2drv[itf_num] = drv_id;
         }
+
+        // bind all endpoints to found driver
+        tu_edpt_bind_driver(dev->ep2drv, desc_itf, drv_len, drv_id);
+
+        break; // exit driver find loop
+      }
+
+      if ( drv_id == TOTAL_DRIVER_COUNT - 1 ) {
+        TU_LOG_USBH("[%u:%u] Interface %u: class = %u subclass = %u protocol = %u is not supported\r\n",
+               dev->rhport, dev_addr, desc_itf->bInterfaceNumber, desc_itf->bInterfaceClass, desc_itf->bInterfaceSubClass, desc_itf->bInterfaceProtocol);
       }
     }
+
+    // next Interface or IAD descriptor
+    p_desc += drv_len;
   }
 
   return true;
 }
 
+void usbh_driver_set_config_complete(uint8_t dev_addr, uint8_t itf_num) {
+  usbh_device_t* dev = get_device(dev_addr);
+
+  for(itf_num++; itf_num < CFG_TUH_INTERFACE_MAX; itf_num++) {
+    // continue with next valid interface
+    // IAD binding interface such as CDCs should return itf_num + 1 when complete
+    // with usbh_driver_set_config_complete()
+    uint8_t const drv_id = dev->itf2drv[itf_num];
+    usbh_class_driver_t const * driver = get_driver(drv_id);
+    if (driver) {
+      TU_LOG_USBH("%s set config: itf = %u\r\n", driver->name, itf_num);
+      driver->set_config(dev_addr, itf_num);
+      break;
+    }
+  }
+
+  // all interface are configured
+  if (itf_num == CFG_TUH_INTERFACE_MAX) {
+    enum_full_complete();
+
+    if (is_hub_addr(dev_addr)) {
+      TU_LOG_USBH("HUB address = %u is mounted\r\n", dev_addr);
+    }else {
+      // Invoke callback if available
+      if (tuh_mount_cb) tuh_mount_cb(dev_addr);
+    }
+  }
+}
+
+static void enum_full_complete(void) {
+  // mark enumeration as complete
+  _dev0.enumerating = 0;
+
+#if CFG_TUH_HUB
+  // get next hub status
+  if (_dev0.hub_addr) hub_edpt_status_xfer(_dev0.hub_addr);
+#endif
+
+}
+
 #endif
diff --git a/src/host/usbh.h b/src/host/usbh.h
index a9790b484..359684169 100644
--- a/src/host/usbh.h
+++ b/src/host/usbh.h
@@ -1,4 +1,4 @@
-/* 
+/*
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
@@ -24,9 +24,6 @@
  * This file is part of the TinyUSB stack.
  */
 
-/** \ingroup group_usbh USB Host Core (USBH)
- *  @{ */
-
 #ifndef _TUSB_USBH_H_
 #define _TUSB_USBH_H_
 
@@ -35,100 +32,280 @@
 #endif
 
 #include "common/tusb_common.h"
-#include "hcd.h"
 
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF
 //--------------------------------------------------------------------+
-typedef enum tusb_interface_status_{
-  TUSB_INTERFACE_STATUS_READY = 0,
-  TUSB_INTERFACE_STATUS_BUSY,
-  TUSB_INTERFACE_STATUS_COMPLETE,
-  TUSB_INTERFACE_STATUS_ERROR,
-  TUSB_INTERFACE_STATUS_INVALID_PARA
-} tusb_interface_status_t;
+
+// forward declaration
+struct tuh_xfer_s;
+typedef struct tuh_xfer_s tuh_xfer_t;
+
+typedef void (*tuh_xfer_cb_t)(tuh_xfer_t* xfer);
+
+// Note1: layout and order of this will be changed in near future
+// it is advised to initialize it using member name
+// Note2: not all field is available/meaningful in callback,
+// some info is not saved by usbh to save SRAM
+struct tuh_xfer_s {
+  uint8_t daddr;
+  uint8_t ep_addr;
+  uint8_t TU_RESERVED;      // reserved
+  xfer_result_t result;
+
+  uint32_t actual_len;      // excluding setup packet
+
+  union {
+    tusb_control_request_t const* setup; // setup packet pointer if control transfer
+    uint32_t buflen;                     // expected length if not control transfer (not available in callback)
+  };
+
+  uint8_t* buffer;           // not available in callback if not control transfer
+  tuh_xfer_cb_t complete_cb;
+  uintptr_t user_data;
+
+  // uint32_t timeout_ms;    // place holder, not supported yet
+};
+
+// Subject to change
+typedef struct {
+  uint8_t daddr;
+  tusb_desc_interface_t desc;
+} tuh_itf_info_t;
+
+// ConfigID for tuh_configure()
+enum {
+  TUH_CFGID_INVALID = 0,
+  TUH_CFGID_RPI_PIO_USB_CONFIGURATION = 100, // cfg_param: pio_usb_configuration_t
+  TUH_CFGID_MAX3421 = 200,
+};
 
 typedef struct {
-  #if CFG_TUSB_DEBUG >= 2
-  char const* name;
-  #endif
+  uint8_t max_nak; // max NAK per endpoint per frame
+  uint8_t cpuctl; // R16: CPU Control Register
+  uint8_t pinctl; // R17: Pin Control Register. FDUPSPI bit is ignored
+} tuh_configure_max3421_t;
+
+typedef union {
+  // For TUH_CFGID_RPI_PIO_USB_CONFIGURATION use pio_usb_configuration_t
+
+  tuh_configure_max3421_t max3421;
+} tuh_configure_param_t;
+
+//--------------------------------------------------------------------+
+// APPLICATION CALLBACK
+//--------------------------------------------------------------------+
 
-  uint8_t class_code;
+//TU_ATTR_WEAK uint8_t tuh_attach_cb (tusb_desc_device_t const *desc_device);
 
-  void (* const init       )(void);
-  bool (* const open       )(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const * itf_desc, uint16_t* outlen);
-  bool (* const set_config )(uint8_t dev_addr, uint8_t itf_num);
-  bool (* const xfer_cb    )(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes);
-  void (* const close      )(uint8_t dev_addr);
-} usbh_class_driver_t;
+// Invoked when a device is mounted (configured)
+TU_ATTR_WEAK void tuh_mount_cb (uint8_t daddr);
 
-typedef bool (*tuh_control_complete_cb_t)(uint8_t dev_addr, tusb_control_request_t const * request, xfer_result_t result);
+// Invoked when a device failed to mount during enumeration process
+// TU_ATTR_WEAK void tuh_mount_failed_cb (uint8_t daddr);
+
+// Invoked when a device is unmounted (detached)
+TU_ATTR_WEAK void tuh_umount_cb(uint8_t daddr);
+
+// Invoked when there is a new usb event, which need to be processed by tuh_task()/tuh_task_ext()
+void tuh_event_hook_cb(uint8_t rhport, uint32_t eventid, bool in_isr);
 
 //--------------------------------------------------------------------+
 // APPLICATION API
 //--------------------------------------------------------------------+
 
+// Configure host stack behavior with dynamic or port-specific parameters.
+// Should be called before tuh_init()
+// - cfg_id   : configure ID (TBD)
+// - cfg_param: configure data, structure depends on the ID
+bool tuh_configure(uint8_t rhport, uint32_t cfg_id, const void* cfg_param);
+
 // Init host stack
 bool tuh_init(uint8_t rhport);
 
-// Check if host stack is already initialized
+// Deinit host stack on rhport
+bool tuh_deinit(uint8_t rhport);
+
+// Check if host stack is already initialized with any roothub ports
+// To check if an rhport is initialized, use tuh_rhport_is_active()
 bool tuh_inited(void);
 
+// Task function should be called in main/rtos loop, extended version of tuh_task()
+// - timeout_ms: millisecond to wait, zero = no wait, 0xFFFFFFFF = wait forever
+// - in_isr: if function is called in ISR
+void tuh_task_ext(uint32_t timeout_ms, bool in_isr);
+
 // Task function should be called in main/rtos loop
-void tuh_task(void);
+TU_ATTR_ALWAYS_INLINE static inline
+void tuh_task(void) {
+  tuh_task_ext(UINT32_MAX, false);
+}
+
+// Check if there is pending events need processing by tuh_task()
+bool tuh_task_event_ready(void);
+
+#ifndef _TUSB_HCD_H_
+extern void hcd_int_handler(uint8_t rhport, bool in_isr);
+#endif
+
+// Interrupt handler alias to HCD with in_isr as optional parameter
+// - tuh_int_handler(rhport) --> hcd_int_handler(rhport, true)
+// - tuh_int_handler(rhport, in_isr) --> hcd_int_handler(rhport, in_isr)
+// Note: this is similar to TU_VERIFY(), _GET_3RD_ARG() is defined in tusb_verify.h
+#define _tuh_int_handler_1arg(_rhport)            hcd_int_handler(_rhport, true)
+#define _tuh_int_hanlder_2arg(_rhport, _in_isr)   hcd_int_handler(_rhport, _in_isr)
+#define tuh_int_handler(...)   _GET_3RD_ARG(__VA_ARGS__, _tuh_int_hanlder_2arg, _tuh_int_handler_1arg, _dummy)(__VA_ARGS__)
 
-// Interrupt handler, name alias to HCD
-extern void hcd_int_handler(uint8_t rhport);
-#define tuh_int_handler   hcd_int_handler
+// Check if roothub port is initialized and active as a host
+bool tuh_rhport_is_active(uint8_t rhport);
 
-tusb_speed_t tuh_device_get_speed (uint8_t dev_addr);
+// Assert/de-assert Bus Reset signal to roothub port. USB specs: it should last 10-50ms
+bool tuh_rhport_reset_bus(uint8_t rhport, bool active);
 
-// Check if device is configured
-bool tuh_device_configured(uint8_t dev_addr);
+//--------------------------------------------------------------------+
+// Device API
+//--------------------------------------------------------------------+
+
+// Get VID/PID of device
+bool tuh_vid_pid_get(uint8_t daddr, uint16_t* vid, uint16_t* pid);
+
+// Get speed of device
+tusb_speed_t tuh_speed_get(uint8_t daddr);
+
+// Check if device is connected and configured
+bool tuh_mounted(uint8_t daddr);
+
+// Check if device is suspended
+TU_ATTR_ALWAYS_INLINE static inline
+bool tuh_suspended(uint8_t daddr) {
+  // TODO implement suspend & resume on host
+  (void) daddr;
+  return false;
+}
 
 // Check if device is ready to communicate with
-TU_ATTR_ALWAYS_INLINE
-static inline bool tuh_device_ready(uint8_t dev_addr)
-{
-  return tuh_device_configured(dev_addr);
+TU_ATTR_ALWAYS_INLINE static inline
+bool tuh_ready(uint8_t daddr) {
+  return tuh_mounted(daddr) && !tuh_suspended(daddr);
 }
 
-// Carry out control transfer
-bool tuh_control_xfer (uint8_t dev_addr, tusb_control_request_t const* request, void* buffer, tuh_control_complete_cb_t complete_cb);
+//--------------------------------------------------------------------+
+// Transfer API
+//--------------------------------------------------------------------+
+
+// Submit a control transfer
+//  - async: complete callback invoked when finished.
+//  - sync : blocking if complete callback is NULL.
+bool tuh_control_xfer(tuh_xfer_t* xfer);
+
+// Submit a bulk/interrupt transfer
+//  - async: complete callback invoked when finished.
+//  - sync : blocking if complete callback is NULL.
+bool tuh_edpt_xfer(tuh_xfer_t* xfer);
+
+// Open a non-control endpoint
+bool tuh_edpt_open(uint8_t daddr, tusb_desc_endpoint_t const * desc_ep);
+
+// Abort a queued transfer. Note: it can only abort transfer that has not been started
+// Return true if a queued transfer is aborted, false if there is no transfer to abort
+bool tuh_edpt_abort_xfer(uint8_t daddr, uint8_t ep_addr);
+
+// Set Configuration (control transfer)
+// config_num = 0 will un-configure device. Note: config_num = config_descriptor_index + 1
+// true on success, false if there is on-going control transfer or incorrect parameters
+// if complete_cb == NULL i.e blocking, user_data should be pointed to xfer_reuslt_t*
+bool tuh_configuration_set(uint8_t daddr, uint8_t config_num,
+                           tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Set Interface (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+// if complete_cb == NULL i.e blocking, user_data should be pointed to xfer_reuslt_t*
+bool tuh_interface_set(uint8_t daddr, uint8_t itf_num, uint8_t itf_alt,
+                       tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
 //--------------------------------------------------------------------+
-// APPLICATION CALLBACK
+// Descriptors Asynchronous (non-blocking)
 //--------------------------------------------------------------------+
-//TU_ATTR_WEAK uint8_t tuh_attach_cb (tusb_desc_device_t const *desc_device);
 
-/** Callback invoked when device is mounted (configured) */
-TU_ATTR_WEAK void tuh_mount_cb (uint8_t dev_addr);
+// Get an descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get(uint8_t daddr, uint8_t type, uint8_t index, void* buffer, uint16_t len,
+                        tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get device descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get_device(uint8_t daddr, void* buffer, uint16_t len,
+                               tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get configuration descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get_configuration(uint8_t daddr, uint8_t index, void* buffer, uint16_t len,
+                                      tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get HID report descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get_hid_report(uint8_t daddr, uint8_t itf_num, uint8_t desc_type, uint8_t index, void* buffer, uint16_t len,
+                                   tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get string descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+// Blocking if complete callback is NULL, in this case 'user_data' must contain xfer_result_t variable
+bool tuh_descriptor_get_string(uint8_t daddr, uint8_t index, uint16_t language_id, void* buffer, uint16_t len,
+                               tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
-/** Callback invoked when device is unmounted (bus reset/unplugged) */
-TU_ATTR_WEAK void tuh_umount_cb(uint8_t dev_addr);
+// Get manufacturer string descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get_manufacturer_string(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len,
+                                            tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get product string descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get_product_string(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len,
+                                       tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+// Get serial string descriptor (control transfer)
+// true on success, false if there is on-going control transfer or incorrect parameters
+bool tuh_descriptor_get_serial_string(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len,
+                                      tuh_xfer_cb_t complete_cb, uintptr_t user_data);
 
 //--------------------------------------------------------------------+
-// CLASS-USBH & INTERNAL API
-// TODO move to usbh_pvt.h
+// Descriptors Synchronous (blocking)
 //--------------------------------------------------------------------+
 
-bool usbh_edpt_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_endpoint_t const * ep_desc);
-bool usbh_edpt_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes);
+// Sync (blocking) version of tuh_descriptor_get()
+// return transfer result
+uint8_t tuh_descriptor_get_sync(uint8_t daddr, uint8_t type, uint8_t index, void* buffer, uint16_t len);
+
+// Sync (blocking) version of tuh_descriptor_get_device()
+// return transfer result
+uint8_t tuh_descriptor_get_device_sync(uint8_t daddr, void* buffer, uint16_t len);
+
+// Sync (blocking) version of tuh_descriptor_get_configuration()
+// return transfer result
+uint8_t tuh_descriptor_get_configuration_sync(uint8_t daddr, uint8_t index, void* buffer, uint16_t len);
 
-// Claim an endpoint before submitting a transfer.
-// If caller does not make any transfer, it must release endpoint for others.
-bool usbh_edpt_claim(uint8_t dev_addr, uint8_t ep_addr);
+// Sync (blocking) version of tuh_descriptor_get_hid_report()
+// return transfer result
+uint8_t tuh_descriptor_get_hid_report_sync(uint8_t daddr, uint8_t itf_num, uint8_t desc_type, uint8_t index, void* buffer, uint16_t len);
 
-void usbh_driver_set_config_complete(uint8_t dev_addr, uint8_t itf_num);
+// Sync (blocking) version of tuh_descriptor_get_string()
+// return transfer result
+uint8_t tuh_descriptor_get_string_sync(uint8_t daddr, uint8_t index, uint16_t language_id, void* buffer, uint16_t len);
 
-uint8_t usbh_get_rhport(uint8_t dev_addr);
+// Sync (blocking) version of tuh_descriptor_get_manufacturer_string()
+// return transfer result
+uint8_t tuh_descriptor_get_manufacturer_string_sync(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len);
 
-uint8_t* usbh_get_enum_buf(void);
+// Sync (blocking) version of tuh_descriptor_get_product_string()
+// return transfer result
+uint8_t tuh_descriptor_get_product_string_sync(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len);
+
+// Sync (blocking) version of tuh_descriptor_get_serial_string()
+// return transfer result
+uint8_t tuh_descriptor_get_serial_string_sync(uint8_t daddr, uint16_t language_id, void* buffer, uint16_t len);
 
 #ifdef __cplusplus
  }
 #endif
 
-#endif /* _TUSB_USBH_H_ */
-
-/** @} */
+#endif
diff --git a/src/host/usbh_control.c b/src/host/usbh_control.c
deleted file mode 100644
index 4dbf8592a..000000000
--- a/src/host/usbh_control.c
+++ /dev/null
@@ -1,141 +0,0 @@
-/* 
- * The MIT License (MIT)
- *
- * Copyright (c) 2020, 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_HOST_ENABLED
-
-#include "tusb.h"
-#include "usbh_hcd.h"
-
-enum
-{
-  STAGE_SETUP,
-  STAGE_DATA,
-  STAGE_ACK
-};
-
-typedef struct
-{
-  tusb_control_request_t request TU_ATTR_ALIGNED(4);
-
-  uint8_t stage;
-  uint8_t* buffer;
-  tuh_control_complete_cb_t complete_cb;
-} usbh_control_xfer_t;
-
-static usbh_control_xfer_t _ctrl_xfer;
-
-//CFG_TUSB_MEM_SECTION CFG_TUSB_MEM_ALIGN
-//static uint8_t _tuh_ctrl_buf[CFG_TUH_ENUMERATION_BUFSZIE];
-
-//--------------------------------------------------------------------+
-// MACRO TYPEDEF CONSTANT ENUM DECLARATION
-//--------------------------------------------------------------------+
-
-bool tuh_control_xfer (uint8_t dev_addr, tusb_control_request_t const* request, void* buffer, tuh_control_complete_cb_t complete_cb)
-{
-  // TODO need to claim the endpoint first
-
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
-  const uint8_t rhport = dev->rhport;
-
-  _ctrl_xfer.request     = (*request);
-  _ctrl_xfer.buffer      = buffer;
-  _ctrl_xfer.stage       = STAGE_SETUP;
-  _ctrl_xfer.complete_cb = complete_cb;
-
-  TU_LOG2("Control Setup: ");
-  TU_LOG2_VAR(request);
-  TU_LOG2("\r\n");
-
-  // Send setup packet
-  TU_ASSERT( hcd_setup_send(rhport, dev_addr, (uint8_t const*) &_ctrl_xfer.request) );
-
-  return true;
-}
-
-static void _xfer_complete(uint8_t dev_addr, xfer_result_t result)
-{
-  TU_LOG2("\r\n");
-  if (_ctrl_xfer.complete_cb) _ctrl_xfer.complete_cb(dev_addr, &_ctrl_xfer.request, result);
-}
-
-bool usbh_control_xfer_cb (uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
-{
-  (void) ep_addr;
-  (void) xferred_bytes;
-
-  usbh_device_t* dev = &_usbh_devices[dev_addr];
-  const uint8_t rhport = dev->rhport;
-
-  tusb_control_request_t const * request = &_ctrl_xfer.request;
-
-  if (XFER_RESULT_SUCCESS != result)
-  {
-    TU_LOG2("Control failed: result = %d\r\n", result);
-
-    // terminate transfer if any stage failed
-    _xfer_complete(dev_addr, result);
-  }else
-  {
-    switch(_ctrl_xfer.stage)
-    {
-      case STAGE_SETUP:
-        _ctrl_xfer.stage = STAGE_DATA;
-        if (request->wLength)
-        {
-          // DATA stage: initial data toggle is always 1
-          hcd_edpt_xfer(rhport, dev_addr, tu_edpt_addr(0, request->bmRequestType_bit.direction), _ctrl_xfer.buffer, request->wLength);
-          return true;
-        }
-        __attribute__((fallthrough));
-
-      case STAGE_DATA:
-        _ctrl_xfer.stage = STAGE_ACK;
-
-        if (request->wLength)
-        {
-          TU_LOG2("Control data:\r\n");
-          TU_LOG2_MEM(_ctrl_xfer.buffer, request->wLength, 2);
-        }
-
-        // ACK stage: toggle is always 1
-        hcd_edpt_xfer(rhport, dev_addr, tu_edpt_addr(0, 1-request->bmRequestType_bit.direction), NULL, 0);
-      break;
-
-      case STAGE_ACK:
-        _xfer_complete(dev_addr, result);
-      break;
-
-      default: return false;
-    }
-  }
-
-  return true;
-}
-
-#endif
diff --git a/src/host/usbh_hcd.h b/src/host/usbh_hcd.h
deleted file mode 100644
index abc7fd250..000000000
--- a/src/host/usbh_hcd.h
+++ /dev/null
@@ -1,112 +0,0 @@
-/* 
- * 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.
- */
-
-/** \ingroup Group_HCD
- *  @{ */
-
-#ifndef _TUSB_USBH_HCD_H_
-#define _TUSB_USBH_HCD_H_
-
-#ifdef __cplusplus
- extern "C" {
-#endif
-
-//--------------------------------------------------------------------+
-// INCLUDE
-//--------------------------------------------------------------------+
-#include "common/tusb_common.h"
-#include "osal/osal.h"
-
-#ifndef CFG_TUH_EP_MAX
-#define CFG_TUH_EP_MAX          9
-#endif
-
-//--------------------------------------------------------------------+
-// USBH-HCD common data structure
-//--------------------------------------------------------------------+
-
-// TODO move to usbh.c
-typedef struct {
-  //------------- port -------------//
-  uint8_t rhport;
-  uint8_t hub_addr;
-  uint8_t hub_port;
-  uint8_t speed;
-
-  //------------- device descriptor -------------//
-  uint16_t vendor_id;
-  uint16_t product_id;
-  uint8_t  ep0_packet_size;
-
-  //------------- configuration descriptor -------------//
-  // uint8_t interface_count; // bNumInterfaces alias
-
-  //------------- device -------------//
-  struct TU_ATTR_PACKED
-  {
-    uint8_t connected    : 1;
-    uint8_t addressed    : 1;
-    uint8_t configured   : 1;
-    uint8_t suspended    : 1;
-  };
-
-  volatile uint8_t state;             // device state, value from enum tusbh_device_state_t
-
-  uint8_t itf2drv[16];  // map interface number to driver (0xff is invalid)
-  uint8_t ep2drv[CFG_TUH_EP_MAX][2]; // map endpoint to driver ( 0xff is invalid )
-
-  struct TU_ATTR_PACKED
-  {
-    volatile bool busy    : 1;
-    volatile bool stalled : 1;
-    volatile bool claimed : 1;
-
-    // TODO merge ep2drv here, 4-bit should be sufficient
-  }ep_status[CFG_TUH_EP_MAX][2];
-
-  // Mutex for claiming endpoint, only needed when using with preempted RTOS
-#if CFG_TUSB_OS != OPT_OS_NONE
-  osal_mutex_def_t mutexdef;
-  osal_mutex_t mutex;
-#endif
-
-} usbh_device_t;
-
-extern usbh_device_t _usbh_devices[CFG_TUSB_HOST_DEVICE_MAX+1]; // including zero-address
-
-//--------------------------------------------------------------------+
-// callback from HCD ISR
-//--------------------------------------------------------------------+
-
-
-
-#ifdef __cplusplus
- }
-#endif
-
-#endif /* _TUSB_USBH_HCD_H_ */
-
-/** @} */
diff --git a/src/host/usbh_pvt.h b/src/host/usbh_pvt.h
new file mode 100644
index 000000000..95de915e9
--- /dev/null
+++ b/src/host/usbh_pvt.h
@@ -0,0 +1,105 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021, 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.
+ */
+
+#ifndef _TUSB_USBH_PVT_H_
+#define _TUSB_USBH_PVT_H_
+
+#include "osal/osal.h"
+#include "common/tusb_fifo.h"
+#include "common/tusb_private.h"
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+#define TU_LOG_USBH(...)      TU_LOG(CFG_TUH_LOG_LEVEL, __VA_ARGS__)
+#define TU_LOG_MEM_USBH(...)  TU_LOG_MEM(CFG_TUH_LOG_LEVEL, __VA_ARGS__)
+#define TU_LOG_BUF_USBH(...)  TU_LOG_BUF(CFG_TUH_LOG_LEVEL, __VA_ARGS__)
+#define TU_LOG_INT_USBH(...)  TU_LOG_INT(CFG_TUH_LOG_LEVEL, __VA_ARGS__)
+#define TU_LOG_HEX_USBH(...)  TU_LOG_HEX(CFG_TUH_LOG_LEVEL, __VA_ARGS__)
+
+enum {
+  USBH_EPSIZE_BULK_MAX = (TUH_OPT_HIGH_SPEED ? TUSB_EPSIZE_BULK_HS : TUSB_EPSIZE_BULK_FS)
+};
+
+//--------------------------------------------------------------------+
+// Class Driver API
+//--------------------------------------------------------------------+
+
+typedef struct {
+  char const* name;
+  bool (* const init       )(void);
+  bool (* const deinit     )(void);
+  bool (* const open       )(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const * itf_desc, uint16_t max_len);
+  bool (* const set_config )(uint8_t dev_addr, uint8_t itf_num);
+  bool (* const xfer_cb    )(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes);
+  void (* const close      )(uint8_t dev_addr);
+} usbh_class_driver_t;
+
+// Invoked when initializing host stack to get additional class drivers.
+// Can be implemented by application to extend/overwrite class driver support.
+// Note: The drivers array must be accessible at all time when stack is active
+usbh_class_driver_t const* usbh_app_driver_get_cb(uint8_t* driver_count) TU_ATTR_WEAK;
+
+// Call by class driver to tell USBH that it has complete the enumeration
+void usbh_driver_set_config_complete(uint8_t dev_addr, uint8_t itf_num);
+
+uint8_t usbh_get_rhport(uint8_t dev_addr);
+
+uint8_t* usbh_get_enum_buf(void);
+
+void usbh_int_set(bool enabled);
+
+void usbh_defer_func(osal_task_func_t func, void *param, bool in_isr);
+
+//--------------------------------------------------------------------+
+// USBH Endpoint API
+//--------------------------------------------------------------------+
+
+// Submit a usb transfer with callback support, require CFG_TUH_API_EDPT_XFER
+bool usbh_edpt_xfer_with_callback(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes,
+                                  tuh_xfer_cb_t complete_cb, uintptr_t user_data);
+
+TU_ATTR_ALWAYS_INLINE
+static inline bool usbh_edpt_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes) {
+  return usbh_edpt_xfer_with_callback(dev_addr, ep_addr, buffer, total_bytes, NULL, 0);
+}
+
+// Claim an endpoint before submitting a transfer.
+// If caller does not make any transfer, it must release endpoint for others.
+bool usbh_edpt_claim(uint8_t dev_addr, uint8_t ep_addr);
+
+// Release claimed endpoint without submitting a transfer
+bool usbh_edpt_release(uint8_t dev_addr, uint8_t ep_addr);
+
+// Check if endpoint transferring is complete
+bool usbh_edpt_busy(uint8_t dev_addr, uint8_t ep_addr);
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif