7 files changed, 581 insertions, 440 deletions
diff --git a/ChangeLog b/ChangeLog
index 3c7188f..c524c7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2016-06-08  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* mcu/usb-stm32f103.c: Rewrite to be event driven API.
+
+	* example-cdc/usb-cdc.c: Update to new USB API.
+	* example-cdc/tty.h: Change tty API to be C string (char*)
+	friendly.
+
 2016-06-02  Niibe Yutaka  <gniibe@fsij.org>
 
 	* contrib/adc-mkl27z.c: Move from mcu.
diff --git a/NEWS b/NEWS
index e3c0838..83f9a85 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,15 @@
 NEWS - Noteworthy changes
 
 
+* Major changes in Chopstx 0.13
+
+  Released 2016-06-xx
+
+** New USB API
+Since USB driver is included, it should be good one.  It used to be
+interrupt based API with callbacks.  Now, it's event driven API.
+
+
 * Major changes in Chopstx 0.12
 
   Released 2016-05-31
diff --git a/example-cdc/sample.c b/example-cdc/sample.c
index 0acd6a8..d5f45b3 100644
--- a/example-cdc/sample.c
+++ b/example-cdc/sample.c
@@ -117,7 +117,7 @@ main (int argc, const char *argv[])
   m = 50;
   while (1)
     {
-      uint8_t s[LINEBUFSIZE];
+      char s[LINEBUFSIZE];
 
       u = 1;
       tty_wait_connection (tty);
diff --git a/example-cdc/tty.h b/example-cdc/tty.h
index bd0f070..77e7f46 100644
--- a/example-cdc/tty.h
+++ b/example-cdc/tty.h
@@ -5,5 +5,5 @@ struct tty;
 struct tty *tty_open (void);
 void tty_wait_configured (struct tty *tty);
 void tty_wait_connection (struct tty *tty);
-int tty_send (struct tty *tty, uint8_t *buf, int count);
-int tty_recv (struct tty *tty, uint8_t *buf, uint32_t *timeout);
+int tty_send (struct tty *tty, const char *buf, int count);
+int tty_recv (struct tty *tty, char *buf, uint32_t *timeout);
diff --git a/example-cdc/usb-cdc.c b/example-cdc/usb-cdc.c
index b132d8d..e9abcac 100644
--- a/example-cdc/usb-cdc.c
+++ b/example-cdc/usb-cdc.c
@@ -30,7 +30,7 @@ static const struct line_coding line_coding0 = {
  *
  * In that case, add argument to TTY_OPEN function and
  * modify TTY_GET function to get the TTY structure.  Functions which
- * directy accesses TTY0 (usb_cb_device_reset and usb_cb_handle_event)
+ * directy accesses TTY0 (usb_device_reset and usb_set_configuration)
  * should be modified, too.
  *
  * Modification of TTY_MAIN thread will be also needed to echo back
@@ -234,10 +234,10 @@ static const uint8_t vcom_string3[28] = {
 #define NUM_INTERFACES 2
 
 
-void
-usb_cb_device_reset (void)
+static void
+usb_device_reset (struct usb_dev *dev)
 {
-  usb_lld_reset (VCOM_FEATURE_BUS_POWERED);
+  usb_lld_reset (dev, VCOM_FEATURE_BUS_POWERED);
 
   /* Initialize Endpoint 0 */
   usb_lld_setup_endpoint (ENDP0, EP_CONTROL, 0, ENDP0_RXADDR, ENDP0_TXADDR, 64);
@@ -256,13 +256,15 @@ usb_cb_device_reset (void)
 
 #define CDC_CTRL_DTR            0x0001
 
-void
-usb_cb_ctrl_write_finish (uint8_t req, uint8_t req_no, struct req_args *arg)
+static void
+usb_ctrl_write_finish (struct usb_dev *dev)
 {
-  uint8_t type_rcp = req & (REQUEST_TYPE|RECIPIENT);
+  struct device_req *arg = &dev->dev_req;
+  uint8_t type_rcp = arg->type & (REQUEST_TYPE|RECIPIENT);
 
   if (type_rcp == (CLASS_REQUEST | INTERFACE_RECIPIENT) && arg->index == 0
-      && USB_SETUP_SET (req) && req_no == USB_CDC_REQ_SET_CONTROL_LINE_STATE)
+      && USB_SETUP_SET (arg->type)
+      && arg->request == USB_CDC_REQ_SET_CONTROL_LINE_STATE)
     {
       struct tty *t = tty_get (arg->index, 0);
 
@@ -272,63 +274,74 @@ usb_cb_ctrl_write_finish (uint8_t req, uint8_t req_no, struct req_args *arg)
       chopstx_cond_signal (&t->cnd);
       chopstx_mutex_unlock (&t->mtx);
     }
+
+  /*
+   * The transaction was already finished.  So, it is no use to call
+   * usb_lld_ctrl_error when the condition does not match.
+   */
 }
 
 
 
 static int
-vcom_port_data_setup (uint8_t req, uint8_t req_no, struct req_args *arg)
+vcom_port_data_setup (struct usb_dev *dev)
 {
-  if (USB_SETUP_GET (req))
+  struct device_req *arg = &dev->dev_req;
+
+  if (USB_SETUP_GET (arg->type))
     {
       struct tty *t = tty_get (arg->index, 0);
 
-      if (req_no == USB_CDC_REQ_GET_LINE_CODING)
-	return usb_lld_reply_request (&t->line_coding,
-				      sizeof (struct line_coding), arg);
+      if (arg->request == USB_CDC_REQ_GET_LINE_CODING)
+	return usb_lld_reply_request (dev, &t->line_coding,
+				      sizeof (struct line_coding));
     }
   else  /* USB_SETUP_SET (req) */
     {
-      if (req_no == USB_CDC_REQ_SET_LINE_CODING
+      if (arg->request == USB_CDC_REQ_SET_LINE_CODING
 	  && arg->len == sizeof (struct line_coding))
 	{
 	  struct tty *t = tty_get (arg->index, 0);
 
-	  usb_lld_set_data_to_recv (&t->line_coding,
-				    sizeof (struct line_coding));
-	  return USB_SUCCESS;
+	  return usb_lld_set_data_to_recv (dev, &t->line_coding,
+					   sizeof (struct line_coding));
 	}
-      else if (req_no == USB_CDC_REQ_SET_CONTROL_LINE_STATE)
-	return USB_SUCCESS;
+      else if (arg->request == USB_CDC_REQ_SET_CONTROL_LINE_STATE)
+	return 0;
     }
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-int
-usb_cb_setup (uint8_t req, uint8_t req_no, struct req_args *arg)
+static int
+usb_setup (struct usb_dev *dev)
 {
-  uint8_t type_rcp = req & (REQUEST_TYPE|RECIPIENT);
+  struct device_req *arg = &dev->dev_req;
+  uint8_t type_rcp = arg->type & (REQUEST_TYPE|RECIPIENT);
 
   if (type_rcp == (CLASS_REQUEST | INTERFACE_RECIPIENT) && arg->index == 0)
-    return vcom_port_data_setup (req, req_no, arg);
+    return vcom_port_data_setup (dev);
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-int
-usb_cb_get_descriptor (uint8_t rcp, uint8_t desc_type, uint8_t desc_index,
-		       struct req_args *arg)
+static int
+usb_get_descriptor (struct usb_dev *dev)
 {
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
+  uint8_t desc_type = (arg->value >> 8);
+  uint8_t desc_index = (arg->value & 0xff);
+
   if (rcp != DEVICE_RECIPIENT)
-    return USB_UNSUPPORT;
+    return -1;
 
   if (desc_type == DEVICE_DESCRIPTOR)
-    return usb_lld_reply_request (vcom_device_desc, sizeof (vcom_device_desc),
-				  arg);
+    return usb_lld_reply_request (dev,
+				  vcom_device_desc, sizeof (vcom_device_desc));
   else if (desc_type == CONFIG_DESCRIPTOR)
-    return usb_lld_reply_request (vcom_config_desc, sizeof (vcom_config_desc),
-				  arg);
+    return usb_lld_reply_request (dev,
+				  vcom_config_desc, sizeof (vcom_config_desc));
   else if (desc_type == STRING_DESCRIPTOR)
     {
       const uint8_t *str;
@@ -353,13 +366,13 @@ usb_cb_get_descriptor (uint8_t rcp, uint8_t desc_type, uint8_t desc_index,
 	  size = sizeof (vcom_string3);
 	  break;
 	default:
-	  return USB_UNSUPPORT;
+	  return -1;
 	}
 
-      return usb_lld_reply_request (str, size, arg);
+      return usb_lld_reply_request (dev, str, size);
     }
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
 static void
@@ -388,83 +401,85 @@ vcom_setup_endpoints_for_interface (uint16_t interface, int stop)
     }
 }
 
-int
-usb_cb_handle_event (uint8_t event_type, uint16_t value)
+static int
+usb_set_configuration (struct usb_dev *dev)
 {
   int i;
   uint8_t current_conf;
 
-  switch (event_type)
+  current_conf = usb_lld_current_configuration (dev);
+  if (current_conf == 0)
     {
-    case USB_EVENT_ADDRESS:
+      if (dev->dev_req.value != 1)
+	return -1;
+
+      usb_lld_set_configuration (dev, 1);
+      for (i = 0; i < NUM_INTERFACES; i++)
+	vcom_setup_endpoints_for_interface (i, 0);
+      chopstx_mutex_lock (&tty0.mtx);
+      tty0.device_state = CONFIGURED;
+      chopstx_cond_signal (&tty0.cnd);
+      chopstx_mutex_unlock (&tty0.mtx);
+    }
+  else if (current_conf != dev->dev_req.value)
+    {
+      if (dev->dev_req.value != 0)
+	return -1;
+
+      usb_lld_set_configuration (dev, 0);
+      for (i = 0; i < NUM_INTERFACES; i++)
+	vcom_setup_endpoints_for_interface (i, 1);
       chopstx_mutex_lock (&tty0.mtx);
       tty0.device_state = ADDRESSED;
+      chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
-      return USB_SUCCESS;
-    case USB_EVENT_CONFIG:
-      current_conf = usb_lld_current_configuration ();
-      if (current_conf == 0)
-	{
-	  if (value != 1)
-	    return USB_UNSUPPORT;
-
-	  usb_lld_set_configuration (1);
-	  for (i = 0; i < NUM_INTERFACES; i++)
-	    vcom_setup_endpoints_for_interface (i, 0);
-	  chopstx_mutex_lock (&tty0.mtx);
-	  tty0.device_state = CONFIGURED;
-	  chopstx_mutex_unlock (&tty0.mtx);
-	}
-      else if (current_conf != value)
-	{
-	  if (value != 0)
-	    return USB_UNSUPPORT;
-
-	  usb_lld_set_configuration (0);
-	  for (i = 0; i < NUM_INTERFACES; i++)
-	    vcom_setup_endpoints_for_interface (i, 1);
-	  chopstx_mutex_lock (&tty0.mtx);
-	  tty0.device_state = ADDRESSED;
-	  chopstx_mutex_unlock (&tty0.mtx);
-	}
-      /* Do nothing when current_conf == value */
-      return USB_SUCCESS;
-    default:
-      break;
     }
 
-  return USB_UNSUPPORT;
+  return 0;
 }
 
 
-int
-usb_cb_interface (uint8_t cmd, struct req_args *arg)
+static int
+usb_set_interface (struct usb_dev *dev)
 {
-  const uint8_t zero = 0;
-  uint16_t interface = arg->index;
-  uint16_t alt = arg->value;
+  uint16_t interface = dev->dev_req.index;
+  uint16_t alt = dev->dev_req.value;
 
   if (interface >= NUM_INTERFACES)
-    return USB_UNSUPPORT;
+    return -1;
 
-  switch (cmd)
+  if (alt != 0)
+    return -1;
+  else
     {
-    case USB_SET_INTERFACE:
-      if (alt != 0)
-	return USB_UNSUPPORT;
-      else
-	{
-	  vcom_setup_endpoints_for_interface (interface, 0);
-	  return USB_SUCCESS;
-	}
+      vcom_setup_endpoints_for_interface (interface, 0);
+      return 0;
+    }
+}
 
-    case USB_GET_INTERFACE:
-      return usb_lld_reply_request (&zero, 1, arg);
+static int
+usb_get_interface (struct usb_dev *dev)
+{
+  const uint8_t zero = 0;
+  uint16_t interface = dev->dev_req.index;
 
-    default:
-    case USB_QUERY_INTERFACE:
-      return USB_SUCCESS;
-    }
+  if (interface >= NUM_INTERFACES)
+    return -1;
+
+  /* We don't have alternate interface, so, always return 0.  */
+  return usb_lld_reply_request (dev, &zero, 1);
+}
+
+static int
+usb_get_status_interface (struct usb_dev *dev)
+{
+  const uint16_t status_info = 0;
+  uint16_t interface = dev->dev_req.index;
+
+  if (interface >= NUM_INTERFACES)
+    return -1;
+
+  return usb_lld_reply_request (dev, &status_info, 2);
 }
 
 
@@ -515,8 +530,8 @@ tty_echo_char (struct tty *t, int c)
 }
 
 
-void
-usb_cb_tx_done (uint8_t ep_num, uint32_t len)
+static void
+usb_tx_done (uint8_t ep_num, uint16_t len)
 {
   struct tty *t = tty_get (-1, ep_num);
 
@@ -598,19 +613,18 @@ tty_input_char (struct tty *t, int c)
   return r;
 }
 
-void
-usb_cb_rx_ready (uint8_t ep_num)
+static void
+usb_rx_ready (uint8_t ep_num, uint16_t len)
 {
   uint8_t recv_buf[64];
   struct tty *t = tty_get (-1, ep_num);
 
   if (ep_num == ENDP3)
     {
-      int i, r;
+      int i;
 
-      r = usb_lld_rx_data_len (ENDP3);
-      usb_lld_rxcpy (recv_buf, ep_num, 0, r);
-      for (i = 0; i < r; i++)
+      usb_lld_rxcpy (recv_buf, ep_num, 0, len);
+      for (i = 0; i < len; i++)
 	if (tty_input_char (t, recv_buf[i]))
 	  break;
 
@@ -652,6 +666,8 @@ static void *
 tty_main (void *arg)
 {
   struct tty *t = arg;
+  struct usb_dev dev;
+  int e;
 
 #if defined(OLDER_SYS_H)
   /*
@@ -660,9 +676,9 @@ tty_main (void *arg)
    *
    * When USB interrupt occurs between usb_lld_init (which assumes
    * ISR) and chopstx_claim_irq (which clears pending interrupt),
-   * invocation of usb_interrupt_handler won't occur.
+   * invocation of usb_lld_event_handler won't occur.
    *
-   * Calling usb_interrupt_handler is no harm even if there were no
+   * Calling usb_lld_event_handler is no harm even if there were no
    * interrupts, thus, we call it unconditionally here, just in case
    * if there is a request.
    *
@@ -671,19 +687,117 @@ tty_main (void *arg)
    * chopstx_claim_irq after usb_lld_init overrides that.
    *
    */
-  usb_lld_init (VCOM_FEATURE_BUS_POWERED);
+  usb_lld_init (&dev, VCOM_FEATURE_BUS_POWERED);
   chopstx_claim_irq (&usb_intr, INTR_REQ_USB);
-  usb_interrupt_handler ();
+  goto event_handle;
 #else
   chopstx_claim_irq (&usb_intr, INTR_REQ_USB);
-  usb_lld_init (VCOM_FEATURE_BUS_POWERED);
+  usb_lld_init (&dev, VCOM_FEATURE_BUS_POWERED);
 #endif
 
   while (1)
     {
       chopstx_poll (NULL, 1, &usb_intr);
       if (usb_intr.ready)
-	usb_interrupt_handler ();
+	{
+	  uint8_t ep_num;
+#if defined(OLDER_SYS_H)
+	event_handle:
+#endif
+	  /*
+	   * When interrupt is detected, call usb_lld_event_handler.
+	   * The event may be one of following:
+	   *    (1) Transfer to endpoint (bulk or interrupt)
+	   *        In this case EP_NUM is encoded in the variable E.
+	   *    (2) "NONE" event: some trasfer was done, but all was
+	   *        done by lower layer, no other work is needed in
+	   *        upper layer.
+	   *    (3) Device events: Reset or Suspend
+	   *    (4) Device requests to the endpoint zero.
+	   *        
+	   */
+	  e = usb_lld_event_handler (&dev);
+	  ep_num = USB_EVENT_ENDP (e);
+
+	  if (ep_num != 0)
+	    {
+	      if (USB_EVENT_TXRX (e))
+		usb_tx_done (ep_num, USB_EVENT_LEN (e));
+	      else
+		usb_rx_ready (ep_num, USB_EVENT_LEN (e));
+	    }
+	  else
+	    switch (USB_EVENT_ID (e))
+	      {
+	      case USB_EVENT_DEVICE_RESET:
+		usb_device_reset (&dev);
+		continue;
+
+	      case USB_EVENT_GET_DESCRIPTOR:
+		if (usb_get_descriptor (&dev) < 0)
+		  usb_lld_ctrl_error (&dev);
+		continue;
+
+		/* The addres is assigned to the device.  We don't
+		 * need to do anything for this actually, but in this
+		 * application, we maintain the USB status of the
+		 * device.  Usually, just "continue" as EVENT_NONE is
+		 * OK.
+		 */
+	      case USB_EVENT_DEVICE_ADDRESSED:
+		chopstx_mutex_lock (&tty0.mtx);
+		tty0.device_state = ADDRESSED;
+		chopstx_cond_signal (&tty0.cnd);
+		chopstx_mutex_unlock (&tty0.mtx);
+		continue;
+
+	      case USB_EVENT_SET_CONFIGURATION:
+		if (usb_set_configuration (&dev) < 0)
+		  usb_lld_ctrl_error (&dev);
+		else
+		  usb_lld_ctrl_good (&dev);
+		continue;
+
+	      case USB_EVENT_SET_INTERFACE:
+		if (usb_set_interface (&dev) < 0)
+		  usb_lld_ctrl_error (&dev);
+		else
+		  usb_lld_ctrl_good (&dev);
+		continue;
+
+		/* Non standard device request.  */
+	      case USB_EVENT_CTRL_REQUEST:
+		if (usb_setup (&dev) < 0)
+		  usb_lld_ctrl_error (&dev);
+		else
+		  usb_lld_ctrl_good (&dev);
+		continue;
+
+		/* Control WRITE transfer finished.  */
+	      case USB_EVENT_CTRL_WRITE_FINISH:
+		usb_ctrl_write_finish (&dev);
+		continue;
+
+	      case USB_EVENT_GET_STATUS_INTERFACE:
+		if (usb_get_status_interface (&dev) < 0)
+		  usb_lld_ctrl_error (&dev);
+		continue;
+
+	      case USB_EVENT_GET_INTERFACE:
+		if (usb_get_interface (&dev) < 0)
+		  usb_lld_ctrl_error (&dev);
+		continue;
+
+	      case USB_EVENT_NONE:
+	      case USB_EVENT_SET_FEATURE_DEVICE:
+	      case USB_EVENT_SET_FEATURE_ENDPOINT:
+	      case USB_EVENT_CLEAR_FEATURE_DEVICE:
+	      case USB_EVENT_CLEAR_FEATURE_ENDPOINT:
+	      case USB_EVENT_DEVICE_SUSPEND:
+	      default:
+		continue;
+	      }
+	}
 
       chopstx_mutex_lock (&t->mtx);
       if (t->device_state == CONFIGURED && t->flag_connected
@@ -743,10 +857,10 @@ check_tx (struct tty *t)
 }
 
 int
-tty_send (struct tty *t, uint8_t *buf, int len)
+tty_send (struct tty *t, const char *buf, int len)
 {
   int r;
-  uint8_t *p;
+  const char *p;
   int count;
 
   p = buf;
@@ -801,7 +915,7 @@ check_rx (void *arg)
  *
  */
 int
-tty_recv (struct tty *t, uint8_t *buf, uint32_t *timeout)
+tty_recv (struct tty *t, char *buf, uint32_t *timeout)
 {
   int r;
   chopstx_poll_cond_t poll_desc;
diff --git a/mcu/usb-stm32f103.c b/mcu/usb-stm32f103.c
index d41c960..3a0ce48 100644
--- a/mcu/usb-stm32f103.c
+++ b/mcu/usb-stm32f103.c
@@ -56,50 +56,20 @@ enum STANDARD_REQUESTS
 enum CONTROL_STATE
 {
   WAIT_SETUP,
-  SETTING_UP,
   IN_DATA,
   OUT_DATA,
   LAST_IN_DATA,
   WAIT_STATUS_IN,
   WAIT_STATUS_OUT,
   STALLED,
-  PAUSE
 };
 
 enum FEATURE_SELECTOR
 {
-  ENDPOINT_STALL,
-  DEVICE_REMOTE_WAKEUP
+  FEATURE_ENDPOINT_HALT=0,
+  FEATURE_DEVICE_REMOTE_WAKEUP=1
 };
 
-struct DATA_INFO
-{
-  uint8_t *addr;
-  uint16_t len;
-  uint8_t require_zlp;
-};
-
-
-struct DEVICE_INFO
-{
-  uint8_t current_configuration;
-  uint8_t current_feature;
-  uint8_t state;
-  /**/
-  uint8_t bmRequestType;
-  uint8_t bRequest;
-  /**/
-  uint16_t value;
-  uint16_t index;
-  uint16_t len;
-};
-
-static struct DEVICE_INFO device_info;
-static struct DATA_INFO data_info;
-
-static struct DEVICE_INFO *const dev_p = &device_info;
-static struct DATA_INFO *const data_p = &data_info;
-
 #define REG_BASE  (0x40005C00UL) /* USB_IP Peripheral Registers base address */
 #define PMA_ADDR  (0x40006000UL) /* USB_IP Packet Memory Area base address   */
 
@@ -181,7 +151,7 @@ static struct DATA_INFO *const data_p = &data_info;
 #define EPRX_DTOG1     (0x1000) /* EndPoint RX Data TOGgle bit1 */
 #define EPRX_DTOG2     (0x2000) /* EndPoint RX Data TOGgle bit1 */
 
-static void usb_handle_transfer (uint16_t istr_value);
+static int usb_handle_transfer (struct usb_dev *dev, uint16_t istr_value);
 
 static void st103_set_btable (void)
 {
@@ -376,14 +346,31 @@ static void st103_ep_clear_dtog_tx (uint8_t ep_num)
     }
 }
 
-void usb_lld_init (uint8_t feature)
+void
+usb_lld_ctrl_error (struct usb_dev *dev)
 {
-  usb_lld_sys_init ();
+  dev->state = STALLED;
+  st103_ep_set_rxtx_status (ENDP0, EP_RX_STALL, EP_TX_STALL);
+}
 
-  dev_p->state = IN_DATA;
+void
+usb_lld_ctrl_good (struct usb_dev *dev)
+{
+  if (dev->dev_req.len == 0)
+    {
+      dev->state = WAIT_STATUS_IN;
+      st103_set_tx_count (ENDP0, 0);
+      st103_ep_set_rxtx_status (ENDP0, EP_RX_NAK, EP_TX_VALID);
+    }
+}
 
-  usb_lld_set_configuration (0);
-  dev_p->current_feature = feature;
+void usb_lld_init (struct usb_dev *dev, uint8_t feature)
+{
+  usb_lld_sys_init ();
+
+  dev->configuration = 0;
+  dev->feature = feature;
+  dev->state = WAIT_SETUP;
 
   /* Reset USB */
   st103_set_cntr (CNTR_FRES);
@@ -406,15 +393,18 @@ void usb_lld_shutdown (void)
   usb_lld_sys_shutdown ();
 }
 
-void
-usb_interrupt_handler (void)
+#define USB_MAKE_EV(event) (event<<24)
+#define USB_MAKE_TXRX(ep_num,txrx,len) ((txrx? (1<<23):0)|(ep_num<<16)|len)
+
+int
+usb_lld_event_handler (struct usb_dev *dev)
 {
   uint16_t istr_value = st103_get_istr ();
 
   if ((istr_value & ISTR_RESET))
     {
       st103_set_istr (CLR_RESET);
-      usb_cb_device_reset ();
+      return USB_MAKE_EV (USB_EVENT_DEVICE_RESET);
     }
   else
     {
@@ -425,42 +415,45 @@ usb_interrupt_handler (void)
 	st103_set_istr (CLR_ERR);
 
       if ((istr_value & ISTR_CTR))
-	usb_handle_transfer (istr_value);
+	return usb_handle_transfer (dev, istr_value);
     }
+
+  return 0;
 }
 
-static void handle_datastage_out (void)
+static void handle_datastage_out (struct usb_dev *dev)
 {
-  if (data_p->addr && data_p->len)
+  if (dev->ctrl_data.addr && dev->ctrl_data.len)
     {
       uint32_t len = st103_get_rx_count (ENDP0);
 
-      if (len > data_p->len)
-	len = data_p->len;
+      if (len > dev->ctrl_data.len)
+	len = dev->ctrl_data.len;
 
-      usb_lld_from_pmabuf (data_p->addr, st103_get_rx_addr (ENDP0), len);
-      data_p->len -= len;
-      data_p->addr += len;
+      usb_lld_from_pmabuf (dev->ctrl_data.addr, st103_get_rx_addr (ENDP0), len);
+      dev->ctrl_data.len -= len;
+      dev->ctrl_data.addr += len;
     }
 
-  if (data_p->len == 0)
+  if (dev->ctrl_data.len == 0)
     {
-      dev_p->state = WAIT_STATUS_IN;
+      dev->state = WAIT_STATUS_IN;
       st103_set_tx_count (ENDP0, 0);
-      st103_ep_set_rxtx_status (ENDP0, EP_RX_STALL, EP_TX_VALID);
+      st103_ep_set_tx_status (ENDP0, EP_TX_VALID);
     }
   else
     {
-      dev_p->state = OUT_DATA;
+      dev->state = OUT_DATA;
       st103_ep_set_rx_status (ENDP0, EP_RX_VALID);
     }
 }
 
-static void handle_datastage_in (void)
+static void handle_datastage_in (struct usb_dev *dev)
 {
   uint32_t len = USB_MAX_PACKET_SIZE;;
+  struct ctrl_data *data_p = &dev->ctrl_data;
 
-  if ((data_p->len == 0) && (dev_p->state == LAST_IN_DATA))
+  if ((data_p->len == 0) && (dev->state == LAST_IN_DATA))
     {
       if (data_p->require_zlp)
 	{
@@ -468,19 +461,19 @@ static void handle_datastage_in (void)
 
 	  /* No more data to send.  Send empty packet */
 	  st103_set_tx_count (ENDP0, 0);
-	  st103_ep_set_rxtx_status (ENDP0, EP_RX_VALID, EP_TX_VALID);
+	  st103_ep_set_tx_status (ENDP0, EP_TX_VALID);
 	}
       else
 	{
-	  /* No more data to send, proceed to receive OUT acknowledge.*/
-	  dev_p->state = WAIT_STATUS_OUT;
-	  st103_ep_set_rxtx_status (ENDP0, EP_RX_VALID, EP_TX_STALL);
+	  /* No more data to send, proceed to receive OUT acknowledge.  */
+	  dev->state = WAIT_STATUS_OUT;
+	  st103_ep_set_rx_status (ENDP0, EP_RX_VALID);
 	}
 
       return;
     }
 
-  dev_p->state = (data_p->len <= len) ? LAST_IN_DATA : IN_DATA;
+  dev->state = (data_p->len <= len) ? LAST_IN_DATA : IN_DATA;
 
   if (len > data_p->len)
     len = data_p->len;
@@ -492,29 +485,30 @@ static void handle_datastage_in (void)
   st103_ep_set_tx_status (ENDP0, EP_TX_VALID);
 }
 
-typedef int (*HANDLER) (uint8_t req, struct req_args *arg);
+typedef int (*HANDLER) (struct usb_dev *dev);
 
-static int std_none (uint8_t req, struct req_args *arg)
+static int std_none (struct usb_dev *dev)
 {
-  (void)req; (void)arg;
-  return USB_UNSUPPORT;
+  (void)dev;
+  return -1;
 }
 
-static int std_get_status (uint8_t req, struct req_args *arg)
+static int std_get_status (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = (arg->type & RECIPIENT);
   uint16_t status_info = 0;
 
   if (arg->value != 0 || arg->len != 2 || (arg->index >> 8) != 0
-      || USB_SETUP_SET (req))
-    return USB_UNSUPPORT;
+      || USB_SETUP_SET (arg->type))
+    return -1;
 
   if (rcp == DEVICE_RECIPIENT)
     {
       if (arg->index == 0)
 	{
 	  /* Get Device Status */
-	  uint8_t feature = dev_p->current_feature;
+	  uint8_t feature = dev->feature;
 
 	  /* Remote Wakeup enabled */
 	  if ((feature & (1 << 5)))
@@ -528,21 +522,15 @@ static int std_get_status (uint8_t req, struct req_args *arg)
 	  else /* Self-powered */
 	    status_info &= ~1;
 
-	  return usb_lld_reply_request (&status_info, 2, arg);
+	  return usb_lld_reply_request (dev, &status_info, 2);
 	}
     }
   else if (rcp == INTERFACE_RECIPIENT)
     {
-      int r;
-
-      if (dev_p->current_configuration == 0)
-	return USB_UNSUPPORT;
-
-      r = usb_cb_interface (USB_QUERY_INTERFACE, arg);
-      if (r != USB_SUCCESS)
-	return USB_UNSUPPORT;
+      if (dev->configuration == 0)
+	return -1;
 
-      return usb_lld_reply_request (&status_info, 2, arg);
+      return USB_EVENT_GET_STATUS_INTERFACE;
     }
   else if (rcp == ENDPOINT_RECIPIENT)
     {
@@ -550,13 +538,13 @@ static int std_get_status (uint8_t req, struct req_args *arg)
       uint16_t status;
 
       if ((arg->index & 0x70) || endpoint == ENDP0)
-	return USB_UNSUPPORT;
+	return -1;
 
       if ((arg->index & 0x80))
 	{
 	  status = st103_ep_get_tx_status (endpoint);
 	  if (status == 0)		/* Disabled */
-	    return USB_UNSUPPORT;
+	    return -1;
 	  else if (status == EP_TX_STALL)
 	    status_info |= 1; /* IN Endpoint stalled */
 	}
@@ -564,33 +552,34 @@ static int std_get_status (uint8_t req, struct req_args *arg)
 	{
 	  status = st103_ep_get_rx_status (endpoint);
 	  if (status == 0)		/* Disabled */
-	    return USB_UNSUPPORT;
+	    return -1;
 	  else if (status == EP_RX_STALL)
 	    status_info |= 1; /* OUT Endpoint stalled */
 	}
 
-      return usb_lld_reply_request (&status_info, 2, arg);
+      return usb_lld_reply_request (dev, &status_info, 2);
     }
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_clear_feature (uint8_t req, struct req_args *arg)
+static int std_clear_feature (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
 
-  if (USB_SETUP_GET (req))
-    return USB_UNSUPPORT;
+  if (USB_SETUP_GET (arg->type))
+    return -1;
 
   if (rcp == DEVICE_RECIPIENT)
     {
       if (arg->len != 0 || arg->index != 0)
-	return USB_UNSUPPORT;
+	return -1;
 
-      if (arg->value == DEVICE_REMOTE_WAKEUP)
+      if (arg->value == FEATURE_DEVICE_REMOTE_WAKEUP)
 	{
-	  dev_p->current_feature &= ~(1 << 5);
-	  return USB_SUCCESS;
+	  dev->feature &= ~(1 << 5);
+	  return USB_EVENT_CLEAR_FEATURE_DEVICE;
 	}
     }
   else if (rcp == ENDPOINT_RECIPIENT)
@@ -598,50 +587,49 @@ static int std_clear_feature (uint8_t req, struct req_args *arg)
       uint8_t endpoint = (arg->index & 0x0f);
       uint16_t status;
 
-      if (dev_p->current_configuration == 0)
-	return USB_UNSUPPORT;
+      if (dev->configuration == 0)
+	return -1;
 
       if (arg->len != 0 || (arg->index >> 8) != 0
-	  || arg->value != ENDPOINT_STALL || endpoint == ENDP0)
-	return USB_UNSUPPORT;
+	  || arg->value != FEATURE_ENDPOINT_HALT || endpoint == ENDP0)
+	return -1;
 
       if ((arg->index & 0x80))
 	status = st103_ep_get_tx_status (endpoint);
       else
 	status = st103_ep_get_rx_status (endpoint);
 
-      if (status == 0)		/* Disabled */
-	return USB_UNSUPPORT;
+      if (status == 0)		/* It's disabled endpoint.  */
+	return -1;
 
-      if (arg->index & 0x80)		/* IN endpoint */
+      if (arg->index & 0x80)	/* IN endpoint */
 	st103_ep_clear_dtog_tx (endpoint);
       else			/* OUT endpoint */
 	st103_ep_clear_dtog_rx (endpoint);
 
-      // event??
-      return USB_SUCCESS;
+      return USB_EVENT_CLEAR_FEATURE_ENDPOINT;
     }
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_set_feature (uint8_t req, struct req_args *arg)
+static int std_set_feature (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
 
-  if (USB_SETUP_GET (req))
-    return USB_UNSUPPORT;
+  if (USB_SETUP_GET (arg->type))
+    return -1;
 
   if (rcp == DEVICE_RECIPIENT)
     {
       if (arg->len != 0 || arg->index != 0)
-	return USB_UNSUPPORT;
+	return -1;
 
-      if (arg->value == DEVICE_REMOTE_WAKEUP)
+      if (arg->value == FEATURE_DEVICE_REMOTE_WAKEUP)
 	{
-	  dev_p->current_feature |= 1 << 5;
-	  // event??
-	  return USB_SUCCESS;
+	  dev->feature |= 1 << 5;
+	  return USB_EVENT_SET_FEATURE_DEVICE;
 	}
     }
   else if (rcp == ENDPOINT_RECIPIENT)
@@ -649,282 +637,290 @@ static int std_set_feature (uint8_t req, struct req_args *arg)
       uint8_t endpoint = (arg->index & 0x0f);
       uint32_t status;
 
-      if (dev_p->current_configuration == 0)
-	return USB_UNSUPPORT;
+      if (dev->configuration == 0)
+	return -1;
 
       if (arg->len != 0 || (arg->index >> 8) != 0
-	  || arg->value != 0 || endpoint == ENDP0)
-	return USB_UNSUPPORT;
+	  || arg->value != FEATURE_ENDPOINT_HALT || endpoint == ENDP0)
+	return -1;
 
       if ((arg->index & 0x80))
 	status = st103_ep_get_tx_status (endpoint);
       else
 	status = st103_ep_get_rx_status (endpoint);
 
-      if (status == 0)		/* Disabled */
-	return USB_UNSUPPORT;
+      if (status == 0)		/* It's disabled endpoint.  */
+	return -1;
 
-      if (arg->index & 0x80)
-	/* IN endpoint */
+      if (arg->index & 0x80)	/* IN endpoint */
 	st103_ep_set_tx_status (endpoint, EP_TX_STALL);
-      else
-	/* OUT endpoint */
+      else			/* OUT endpoint */
 	st103_ep_set_rx_status (endpoint, EP_RX_STALL);
 
-      // event??
-      return USB_SUCCESS;
+      return USB_EVENT_SET_FEATURE_ENDPOINT;
     }
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_set_address (uint8_t req, struct req_args *arg)
+static int std_set_address (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
 
-  if (USB_SETUP_GET (req))
-    return USB_UNSUPPORT;
+  if (USB_SETUP_GET (arg->type))
+    return -1;
 
   if (rcp == DEVICE_RECIPIENT && arg->len == 0 && arg->value <= 127
-      && arg->index == 0 && dev_p->current_configuration == 0)
-    return USB_SUCCESS;
+      && arg->index == 0 && dev->configuration == 0)
+    return USB_EVENT_NONE;
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_get_descriptor (uint8_t req, struct req_args *arg)
+static int std_get_descriptor (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
-
-  if (USB_SETUP_SET (req))
-    return USB_UNSUPPORT;
+  struct device_req *arg = &dev->dev_req;
+  if (USB_SETUP_SET (arg->type))
+    return -1;
 
-  return usb_cb_get_descriptor (rcp, (arg->value >> 8),
-				(arg->value & 0xff), arg);
+  return USB_EVENT_GET_DESCRIPTOR;
 }
 
-static int std_get_configuration (uint8_t req,  struct req_args *arg)
+static int std_get_configuration (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
 
-  if (USB_SETUP_SET (req))
-    return USB_UNSUPPORT;
+  if (USB_SETUP_SET (arg->type))
+    return -1;
+
+  if (arg->value != 0 || arg->index != 0 || arg->len != 1)
+    return -1;
 
   if (rcp == DEVICE_RECIPIENT)
-    return usb_lld_reply_request (&dev_p->current_configuration, 1, arg);
+    return usb_lld_reply_request (dev, &dev->configuration, 1);
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_set_configuration (uint8_t req, struct req_args *arg)
+static int std_set_configuration (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
+
+  if (USB_SETUP_GET (arg->type))
+    return -1;
 
-  if (USB_SETUP_GET (req))
-    return USB_UNSUPPORT;
+  if (arg->index != 0 || arg->len != 0)
+    return -1;
 
-  if (rcp == DEVICE_RECIPIENT && arg->index == 0 && arg->len == 0)
-    return usb_cb_handle_event (USB_EVENT_CONFIG, arg->value);
+  if (rcp == DEVICE_RECIPIENT)
+    return USB_EVENT_SET_CONFIGURATION;
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_get_interface (uint8_t req, struct req_args *arg)
+static int std_get_interface (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
 
-  if (USB_SETUP_SET (req))
-    return USB_UNSUPPORT;
+  if (USB_SETUP_SET (arg->type))
+    return -1;
 
-  if (rcp == INTERFACE_RECIPIENT)
-    {
-      if (arg->value != 0 || (arg->index >> 8) != 0 || arg->len != 1)
-	return USB_UNSUPPORT;
+  if (arg->value != 0 || (arg->index >> 8) != 0 || arg->len != 1)
+    return -1;
 
-      if (dev_p->current_configuration == 0)
-	return USB_UNSUPPORT;
+  if (dev->configuration == 0)
+    return -1;
 
-      return usb_cb_interface (USB_GET_INTERFACE, arg);
-    }
+  if (rcp == INTERFACE_RECIPIENT)
+    return USB_EVENT_GET_INTERFACE;
 
-  return USB_UNSUPPORT;
+  return -1;
 }
 
-static int std_set_interface (uint8_t req, struct req_args *arg)
+static int std_set_interface (struct usb_dev *dev)
 {
-  uint8_t rcp = req & RECIPIENT;
+  struct device_req *arg = &dev->dev_req;
+  uint8_t rcp = arg->type & RECIPIENT;
 
-  if (USB_SETUP_GET (req) || rcp != INTERFACE_RECIPIENT
+  if (USB_SETUP_GET (arg->type) || rcp != INTERFACE_RECIPIENT
       || arg->len != 0 || (arg->index >> 8) != 0
-      || (arg->value >> 8) != 0 || dev_p->current_configuration == 0)
-    return USB_UNSUPPORT;
+      || (arg->value >> 8) != 0 || dev->configuration == 0)
+    return -1;
 
-  return usb_cb_interface (USB_SET_INTERFACE, arg);
+  return USB_EVENT_SET_INTERFACE;
 }
 
 
-static void handle_setup0 (void)
+static int handle_setup0 (struct usb_dev *dev)
 {
   const uint16_t *pw;
   uint16_t w;
   uint8_t req_no;
-  int r = USB_UNSUPPORT;
   HANDLER handler;
 
   pw = (uint16_t *)(PMA_ADDR + (uint8_t *)(st103_get_rx_addr (ENDP0) * 2));
   w = *pw++;
 
-  dev_p->bmRequestType = w & 0xff;
-  dev_p->bRequest = req_no = w >> 8;
+  dev->dev_req.type = (w & 0xff);
+  dev->dev_req.request = req_no = (w >> 8);
   pw++;
-  dev_p->value = *pw++;
+  dev->dev_req.value = *pw++;
   pw++;
-  dev_p->index = *pw++;
+  dev->dev_req.index = *pw++;
   pw++;
-  dev_p->len = *pw;
+  dev->dev_req.len = *pw;
 
-  data_p->addr = NULL;
-  data_p->len = 0;
-  data_p->require_zlp = 0;
+  dev->ctrl_data.addr = NULL;
+  dev->ctrl_data.len = 0;
+  dev->ctrl_data.require_zlp = 0;
 
-  if ((dev_p->bmRequestType & REQUEST_TYPE) == STANDARD_REQUEST)
+  if ((dev->dev_req.type & REQUEST_TYPE) == STANDARD_REQUEST)
     {
-      if (req_no < TOTAL_REQUEST)
-	{
-	  switch (req_no)
-	    {
-	    case 0: handler = std_get_status;  break;
-	    case 1: handler = std_clear_feature;  break;
-	    case 3: handler = std_set_feature;  break;
-	    case 5: handler = std_set_address;  break;
-	    case 6: handler = std_get_descriptor;  break;
-	    case 8: handler = std_get_configuration;  break;
-	    case 9: handler = std_set_configuration;  break;
-	    case 10: handler = std_get_interface;  break;
-	    case 11: handler = std_set_interface;  break;
-	    default: handler = std_none;  break;
-	    }
+      int r;
 
-	  r = (*handler) (dev_p->bmRequestType,
-			  (struct req_args *)&dev_p->value);
+      switch (req_no)
+	{
+	case 0: handler = std_get_status;  break;
+	case 1: handler = std_clear_feature;  break;
+	case 3: handler = std_set_feature;  break;
+	case 5: handler = std_set_address;  break;
+	case 6: handler = std_get_descriptor;  break;
+	case 8: handler = std_get_configuration;  break;
+	case 9: handler = std_set_configuration;  break;
+	case 10: handler = std_get_interface;  break;
+	case 11: handler = std_set_interface;  break;
+	default: handler = std_none;  break;
 	}
-    }
-  else
-    r = usb_cb_setup (dev_p->bmRequestType, req_no,
-		      (struct req_args *)&dev_p->value);
 
-  if (r != USB_SUCCESS)
-    dev_p->state = STALLED;
-  else
-    {
-      if (USB_SETUP_SET (dev_p->bmRequestType))
+      if ((r = (*handler) (dev)) <= 0)
 	{
-	  if (dev_p->len == 0)
-	    {
-	      dev_p->state = WAIT_STATUS_IN;
-	      st103_set_tx_count (ENDP0, 0);
-	      st103_ep_set_rxtx_status (ENDP0, EP_RX_STALL, EP_TX_VALID);
-	    }
+	  /* Handling finished in standard way.  */
+	  if (r == 0)
+	    usb_lld_ctrl_good (dev);
 	  else
-	    {
-	      dev_p->state = OUT_DATA;
-	      st103_ep_set_rx_status (ENDP0, EP_RX_VALID);
-	    }
+	    usb_lld_ctrl_error (dev);
+	  return 0;
 	}
+      else
+	return r;
     }
+  else
+    return USB_EVENT_CTRL_REQUEST;
 }
 
-static void handle_in0 (void)
+static int handle_in0 (struct usb_dev *dev)
 {
-  if (dev_p->state == IN_DATA || dev_p->state == LAST_IN_DATA)
-    handle_datastage_in ();
-  else if (dev_p->state == WAIT_STATUS_IN)
+  int r = 0;
+
+  if (dev->state == IN_DATA || dev->state == LAST_IN_DATA)
+    handle_datastage_in (dev);
+  else if (dev->state == WAIT_STATUS_IN)
     {
-      if ((dev_p->bRequest == SET_ADDRESS) &&
-	  ((dev_p->bmRequestType & (REQUEST_TYPE | RECIPIENT))
+      dev->state = WAIT_SETUP;
+
+      if ((dev->dev_req.request == SET_ADDRESS) &&
+	  ((dev->dev_req.type & (REQUEST_TYPE | RECIPIENT))
 	   == (STANDARD_REQUEST | DEVICE_RECIPIENT)))
 	{
-	  st103_set_daddr (dev_p->value);
-	  usb_cb_handle_event (USB_EVENT_ADDRESS, dev_p->value);
+	  st103_set_daddr (dev->dev_req.value);
+	  r = USB_EVENT_DEVICE_ADDRESSED;
 	}
       else
-	usb_cb_ctrl_write_finish (dev_p->bmRequestType, dev_p->bRequest,
-				  (struct req_args *)&dev_p->value);
-
-      dev_p->state = STALLED;
+	r = USB_EVENT_CTRL_WRITE_FINISH;
     }
   else
-    dev_p->state = STALLED;
+    {
+      dev->state = STALLED;
+      st103_ep_set_rxtx_status (ENDP0, EP_RX_STALL, EP_TX_STALL);
+    }
+
+  return r;
 }
 
-static void handle_out0 (void)
-{
-  if (dev_p->state == IN_DATA || dev_p->state == LAST_IN_DATA)
-    /* host aborts the transfer before finish */
-    dev_p->state = STALLED;
-  else if (dev_p->state == OUT_DATA)
-    handle_datastage_out ();
-  else if (dev_p->state == WAIT_STATUS_OUT)
-    dev_p->state = STALLED;
-  /* Unexpect state, STALL the endpoint */
+static void handle_out0 (struct usb_dev *dev)
+{
+  if (dev->state == OUT_DATA)
+    /* Usual case.  */
+    handle_datastage_out (dev);
+  else if (dev->state == WAIT_STATUS_OUT)
+    /*
+     * Control READ transfer finished by ZLP.
+     * Leave ENDP0 status RX_NAK, TX_NAK.
+     */
+    dev->state = WAIT_SETUP;
   else
-    dev_p->state = STALLED;
+    {
+      /*
+       * dev->state == IN_DATA || dev->state == LAST_IN_DATA
+       * (Host aborts the transfer before finish)
+       * Or else, unexpected state.
+       * STALL the endpoint, until we receive the next SETUP token.
+       */
+      dev->state = STALLED;
+      st103_ep_set_rxtx_status (ENDP0, EP_RX_STALL, EP_TX_STALL);
+    }
 }
-
-static void
-usb_handle_transfer (uint16_t istr_value)
+
+
+static int
+usb_handle_transfer (struct usb_dev *dev, uint16_t istr_value)
 {
   uint16_t ep_value = 0;
-  uint8_t ep_index;
+  uint8_t ep_num = (istr_value & ISTR_EP_ID);
 
-  ep_index = (istr_value & ISTR_EP_ID);
-  /* Decode and service non control endpoints interrupt  */
-  /* process related endpoint register */
-  ep_value = st103_get_epreg (ep_index);
+  ep_value = st103_get_epreg (ep_num);
 
-  if (ep_index == 0)
+  if (ep_num == 0)
     {
       if ((ep_value & EP_CTR_TX))
 	{
-	  st103_ep_clear_ctr_tx (ep_index);
-	  handle_in0 ();
+	  st103_ep_clear_ctr_tx (ep_num);
+	  return USB_MAKE_EV (handle_in0 (dev));
 	}
 
       if ((ep_value & EP_CTR_RX))
 	{
-	  st103_ep_clear_ctr_rx (ep_index);
+	  st103_ep_clear_ctr_rx (ep_num);
 
 	  if ((ep_value & EP_SETUP))
-	    handle_setup0 ();
+	    return USB_MAKE_EV (handle_setup0 (dev));
 	  else
-	    handle_out0 ();
+	    {
+	      handle_out0 (dev);
+	      return 0;
+	    }
 	}
-
-      if (dev_p->state == STALLED)
-	st103_ep_set_rxtx_status (ENDP0, EP_RX_STALL, EP_TX_STALL);
     }
   else
     {
+      uint16_t len;
+
       if ((ep_value & EP_CTR_RX))
 	{
-	  st103_ep_clear_ctr_rx (ep_index);
-	  usb_cb_rx_ready (ep_index);
+	  len = st103_get_rx_count (ep_num);
+	  st103_ep_clear_ctr_rx (ep_num);
+	  return USB_MAKE_TXRX (ep_num, 0, len);
 	}
 
       if ((ep_value & EP_CTR_TX))
 	{
-	  uint32_t len = st103_get_tx_count (ep_index);
-
-	  st103_ep_clear_ctr_tx (ep_index);
-	  usb_cb_tx_done (ep_index, len);
+	  len = st103_get_tx_count (ep_num);
+	  st103_ep_clear_ctr_tx (ep_num);
+	  return  USB_MAKE_TXRX (ep_num, 1, len);
 	}
     }
+
+  return 0;
 }
 
-void usb_lld_reset (uint8_t feature)
+void usb_lld_reset (struct usb_dev *dev, uint8_t feature)
 {
-  usb_lld_set_configuration (0);
-  dev_p->current_feature = feature;
+  usb_lld_set_configuration (dev, 0);
+  dev->feature = feature;
   st103_set_btable ();
   st103_set_daddr (0);
 }
@@ -954,16 +950,6 @@ void usb_lld_tx_enable (int ep_num, size_t len)
   st103_ep_set_tx_status (ep_num, EP_TX_VALID);
 }
 
-int usb_lld_tx_data_len (int ep_num)
-{
-  return st103_get_tx_count (ep_num);
-}
-
-int usb_lld_rx_data_len (int ep_num)
-{
-  return st103_get_rx_count (ep_num);
-}
-
 void usb_lld_stall_tx (int ep_num)
 {
   st103_ep_set_tx_status (ep_num, EP_TX_STALL);
@@ -1021,20 +1007,22 @@ void usb_lld_setup_endpoint (int ep_num, int ep_type, int ep_kind,
   st103_set_epreg (ep_num, epreg_value);
 }
 
-void usb_lld_set_configuration (uint8_t config)
+void usb_lld_set_configuration (struct usb_dev *dev, uint8_t config)
 {
-  dev_p->current_configuration = config;
+  dev->configuration = config;
 }
 
-uint8_t usb_lld_current_configuration (void)
+uint8_t usb_lld_current_configuration (struct usb_dev *dev)
 {
-  return dev_p->current_configuration;
+  return dev->configuration;
 }
 
-void usb_lld_set_data_to_recv (void *p, size_t len)
+int usb_lld_set_data_to_recv (struct usb_dev *dev, void *p, size_t len)
 {
+  struct ctrl_data *data_p = &dev->ctrl_data;
   data_p->addr = p;
   data_p->len = len;
+  return 0;
 }
 
 void usb_lld_to_pmabuf (const void *src, uint16_t addr, size_t n)
@@ -1118,9 +1106,10 @@ void usb_lld_from_pmabuf (void *dst, uint16_t addr, size_t n)
  * BUFLEN: size of the data.
  */
 int
-usb_lld_reply_request (const void *buf, size_t buflen, struct req_args *ctl)
+usb_lld_reply_request (struct usb_dev *dev, const void *buf, size_t buflen)
 {
-  uint32_t len_asked = ctl->len;
+  struct ctrl_data *data_p = &dev->ctrl_data;
+  uint32_t len_asked = dev->dev_req.len;
   uint32_t len;
 
   data_p->addr = (void *)buf;
@@ -1136,12 +1125,12 @@ usb_lld_reply_request (const void *buf, size_t buflen, struct req_args *ctl)
   if (data_p->len < USB_MAX_PACKET_SIZE)
     {
       len = data_p->len;
-      dev_p->state = LAST_IN_DATA;
+      dev->state = LAST_IN_DATA;
     }
   else
     {
       len = USB_MAX_PACKET_SIZE;
-      dev_p->state = IN_DATA;
+      dev->state = IN_DATA;
     }
 
   if (len)
@@ -1152,6 +1141,6 @@ usb_lld_reply_request (const void *buf, size_t buflen, struct req_args *ctl)
     }
 
   st103_set_tx_count (ENDP0, len);
-  st103_ep_set_tx_status (ENDP0, EP_TX_VALID);
-  return USB_SUCCESS;
+  st103_ep_set_rxtx_status (ENDP0, EP_RX_NAK, EP_TX_VALID);
+  return USB_EVENT_NONE;
 }
diff --git a/usb_lld.h b/usb_lld.h
index 0dcab3b..4c25d7c 100644
--- a/usb_lld.h
+++ b/usb_lld.h
@@ -37,45 +37,52 @@ enum DESCRIPTOR_TYPE
 #define USB_SETUP_SET(req) ((req & REQUEST_DIR) == 0)
 #define USB_SETUP_GET(req) ((req & REQUEST_DIR) != 0)
 
-enum
-{
-  USB_UNSUPPORT = 0,
-  USB_SUCCESS = 1,
-};
-
-struct req_args {
+struct device_req {
+  uint8_t type;
+  uint8_t request;
   uint16_t value;
   uint16_t index;
   uint16_t len;
 };
 
-void usb_cb_device_reset (void);
-int usb_cb_setup (uint8_t req, uint8_t req_no, struct req_args *arg);
-int usb_cb_interface (uint8_t cmd, struct req_args *arg);
-int usb_cb_get_descriptor (uint8_t rcp, uint8_t desc_type, uint8_t desc_index,
-			   struct req_args *arg);
-int usb_cb_handle_event (uint8_t event_type, uint16_t value);
-void usb_cb_ctrl_write_finish (uint8_t req, uint8_t req_no,
-			       struct req_args *arg);
-void usb_cb_tx_done (uint8_t ep_num, uint32_t len);
-void usb_cb_rx_ready (uint8_t ep_num);
+struct ctrl_data {
+  uint8_t *addr;
+  uint16_t len;
+  uint8_t require_zlp;
+};
 
-enum {
-  USB_EVENT_ADDRESS,
-  USB_EVENT_CONFIG,
-  USB_EVENT_SUSPEND,
-  USB_EVENT_WAKEUP,
-  USB_EVENT_STALL,
+struct usb_dev {
+  uint8_t configuration;
+  uint8_t feature;
+  uint8_t state;
+  struct device_req dev_req;
+  struct ctrl_data ctrl_data;
 };
 
 enum {
-  USB_SET_INTERFACE,
-  USB_GET_INTERFACE,
-  USB_QUERY_INTERFACE,
+  USB_EVENT_NONE=0,		/* Processed in lower layer.  */
+  /* Device reset and suspend.  */
+  USB_EVENT_DEVICE_RESET,
+  USB_EVENT_DEVICE_SUSPEND,
+  /* Device Requests (Control WRITE Transfer): Standard */
+  USB_EVENT_SET_CONFIGURATION,
+  USB_EVENT_SET_INTERFACE,
+  USB_EVENT_SET_FEATURE_DEVICE,
+  USB_EVENT_SET_FEATURE_ENDPOINT,
+  USB_EVENT_CLEAR_FEATURE_DEVICE,
+  USB_EVENT_CLEAR_FEATURE_ENDPOINT,
+  /* Device Requests (Control READ Transfer): Standard */
+  USB_EVENT_GET_STATUS_INTERFACE,
+  USB_EVENT_GET_DESCRIPTOR,
+  USB_EVENT_GET_INTERFACE,
+  /* Device Requests (Control READ/WRITE Transfer): Non-Standard */
+  USB_EVENT_CTRL_REQUEST,
+  USB_EVENT_CTRL_WRITE_FINISH,
+  /* Device addressed.  */
+  USB_EVENT_DEVICE_ADDRESSED,
 };
 
-enum DEVICE_STATE
-{
+enum DEVICE_STATE {
   UNCONNECTED,
   ATTACHED,
   POWERED,
@@ -84,17 +91,32 @@ enum DEVICE_STATE
   CONFIGURED
 };
 
-void usb_lld_init (uint8_t feature);
-int usb_lld_reply_request (const void *buf, size_t buflen,
-			   struct req_args *arg);
-int usb_lld_rx_data_len (int ep_num);
-void usb_lld_reset (uint8_t feature);
-void usb_lld_set_configuration (uint8_t config);
-uint8_t usb_lld_current_configuration (void);
+void usb_lld_init (struct usb_dev *dev, uint8_t feature);
+
+/*
+ * Return value is encoded integer:
+ *     event-no:    8-bit, 0 if TX/RX
+ *     tx/rx-flag:  1-bit, 0 if rx, 1 if tx
+ *     endpoint no: 7-bit
+ *     length:      16-bit
+ */
+#define USB_EVENT_TXRX(e) ((e >> 23) & 1)
+#define USB_EVENT_LEN(e) (e & 0xffff)
+#define USB_EVENT_ENDP(e) ((e >> 16) & 0x7f)
+#define USB_EVENT_ID(e) ((e >> 24))
+int usb_lld_event_handler (struct usb_dev *dev);
+
+int usb_lld_reply_request (struct usb_dev *dev,
+			   const void *buf, size_t buflen);
+int usb_lld_set_data_to_recv (struct usb_dev *dev, void *p, size_t len);
+void usb_lld_ctrl_error (struct usb_dev *dev);
+void usb_lld_ctrl_good (struct usb_dev *dev);
+
+void usb_lld_reset (struct usb_dev *dev, uint8_t feature);
+void usb_lld_set_configuration (struct usb_dev *dev, uint8_t config);
+uint8_t usb_lld_current_configuration (struct usb_dev *dev);
 void usb_lld_prepare_shutdown (void);
 void usb_lld_shutdown (void);
-void usb_interrupt_handler (void);
-void usb_lld_set_data_to_recv (void *p, size_t len);
 
 #ifdef MCU_KINETIS_L
 void usb_lld_tx_enable_buf (int ep_num, const void *buf, size_t len);
@@ -118,10 +140,9 @@ void usb_lld_setup_endpoint (int ep_num, int ep_type, int ep_kind,
 void usb_lld_stall_tx (int ep_num);
 void usb_lld_stall_rx (int ep_num);
 
-int usb_lld_tx_data_len (int ep_num);
 void usb_lld_txcpy (const void *src, int ep_num, int offset, size_t len);
 void usb_lld_write (uint8_t ep_num, const void *buf, size_t len);
+void usb_lld_rxcpy (uint8_t *dst, int ep_num, int offset, size_t len);
 void usb_lld_to_pmabuf (const void *src, uint16_t addr, size_t n);
 void usb_lld_from_pmabuf (void *dst, uint16_t addr, size_t n);
-void usb_lld_rxcpy (uint8_t *dst, int ep_num, int offset, size_t len);
 #endif