Index: uspace/lib/usbvirt/src/ipc_hc.c
===================================================================
--- uspace/lib/usbvirt/src/ipc_hc.c	(revision e25a849b8efb13e779f8c2ac0844acd744764f61)
+++ uspace/lib/usbvirt/src/ipc_hc.c	(revision 42e217243c8630a28314b93123cef778a33d968e)
@@ -43,4 +43,15 @@
 #include <usb/debug.h>
 
+/** Send control read transfer to virtual USB device.
+ *
+ * @param phone IPC phone to the virtual device.
+ * @param ep Target endpoint number.
+ * @param setup_buffer Setup buffer.
+ * @param setup_buffer_size Setup buffer size in bytes.
+ * @param data_buffer Data buffer (DATA stage of control transfer).
+ * @param data_buffer_size Size of data buffer in bytes.
+ * @param data_transfered_size Number of actually transferred bytes.
+ * @return Error code.
+ */
 int usbvirt_ipc_send_control_read(int phone, usb_endpoint_t ep,
     void *setup_buffer, size_t setup_buffer_size,
@@ -92,4 +103,14 @@
 }
 
+/** Send control write transfer to virtual USB device.
+ *
+ * @param phone IPC phone to the virtual device.
+ * @param ep Target endpoint number.
+ * @param setup_buffer Setup buffer.
+ * @param setup_buffer_size Setup buffer size in bytes.
+ * @param data_buffer Data buffer (DATA stage of control transfer).
+ * @param data_buffer_size Size of data buffer in bytes.
+ * @return Error code.
+ */
 int usbvirt_ipc_send_control_write(int phone, usb_endpoint_t ep,
     void *setup_buffer, size_t setup_buffer_size,
@@ -125,4 +146,14 @@
 }
 
+/** Request data transfer from virtual USB device.
+ *
+ * @param phone IPC phone to the virtual device.
+ * @param ep Target endpoint number.
+ * @param tr_type Transfer type (interrupt or bulk).
+ * @param data Data buffer.
+ * @param data_size Size of the data buffer in bytes.
+ * @param act_size Number of actually returned bytes.
+ * @return Error code.
+ */
 int usbvirt_ipc_send_data_in(int phone, usb_endpoint_t ep,
     usb_transfer_type_t tr_type, void *data, size_t data_size, size_t *act_size)
@@ -167,4 +198,13 @@
 }
 
+/** Send data to virtual USB device.
+ *
+ * @param phone IPC phone to the virtual device.
+ * @param ep Target endpoint number.
+ * @param tr_type Transfer type (interrupt or bulk).
+ * @param data Data buffer.
+ * @param data_size Size of the data buffer in bytes.
+ * @return Error code.
+ */
 int usbvirt_ipc_send_data_out(int phone, usb_endpoint_t ep,
     usb_transfer_type_t tr_type, void *data, size_t data_size)