diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
index daac75b7ae..d807ce5771 100644
--- a/hw/usb/dev-serial.c
+++ b/hw/usb/dev-serial.c
@@ -358,13 +358,56 @@ static void usb_serial_handle_control(USBDevice *dev, USBPacket *p,
     }
 }
 
+static void usb_serial_token_in(USBSerialState *s, USBPacket *p)
+{
+    int first_len, len;
+    uint8_t header[2];
+
+    first_len = RECV_BUF - s->recv_ptr;
+    len = p->iov.size;
+    if (len <= 2) {
+        p->status = USB_RET_NAK;
+        return;
+    }
+    header[0] = usb_get_modem_lines(s) | 1;
+    /* We do not have the uart details */
+    /* handle serial break */
+    if (s->event_trigger && s->event_trigger & FTDI_BI) {
+        s->event_trigger &= ~FTDI_BI;
+        header[1] = FTDI_BI;
+        usb_packet_copy(p, header, 2);
+        return;
+    } else {
+        header[1] = 0;
+    }
+    len -= 2;
+    if (len > s->recv_used) {
+        len = s->recv_used;
+    }
+    if (!len) {
+        p->status = USB_RET_NAK;
+        return;
+    }
+    if (first_len > len) {
+        first_len = len;
+    }
+    usb_packet_copy(p, header, 2);
+    usb_packet_copy(p, s->recv_buf + s->recv_ptr, first_len);
+    if (len > first_len) {
+        usb_packet_copy(p, s->recv_buf, len - first_len);
+    }
+    s->recv_used -= len;
+    s->recv_ptr = (s->recv_ptr + len) % RECV_BUF;
+
+    return;
+}
+
 static void usb_serial_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBSerialState *s = (USBSerialState *)dev;
     uint8_t devep = p->ep->nr;
     struct iovec *iov;
-    uint8_t header[2];
-    int i, first_len, len;
+    int i;
 
     switch (p->pid) {
     case USB_TOKEN_OUT:
@@ -382,38 +425,7 @@ static void usb_serial_handle_data(USBDevice *dev, USBPacket *p)
     case USB_TOKEN_IN:
         if (devep != 1)
             goto fail;
-        first_len = RECV_BUF - s->recv_ptr;
-        len = p->iov.size;
-        if (len <= 2) {
-            p->status = USB_RET_NAK;
-            break;
-        }
-        header[0] = usb_get_modem_lines(s) | 1;
-        /* We do not have the uart details */
-        /* handle serial break */
-        if (s->event_trigger && s->event_trigger & FTDI_BI) {
-            s->event_trigger &= ~FTDI_BI;
-            header[1] = FTDI_BI;
-            usb_packet_copy(p, header, 2);
-            break;
-        } else {
-            header[1] = 0;
-        }
-        len -= 2;
-        if (len > s->recv_used)
-            len = s->recv_used;
-        if (!len) {
-            p->status = USB_RET_NAK;
-            break;
-        }
-        if (first_len > len)
-            first_len = len;
-        usb_packet_copy(p, header, 2);
-        usb_packet_copy(p, s->recv_buf + s->recv_ptr, first_len);
-        if (len > first_len)
-            usb_packet_copy(p, s->recv_buf, len - first_len);
-        s->recv_used -= len;
-        s->recv_ptr = (s->recv_ptr + len) % RECV_BUF;
+        usb_serial_token_in(s, p);
         break;
 
     default: