Index: uspace/drv/uhci-hcd/utils/device_keeper.c
===================================================================
--- uspace/drv/uhci-hcd/utils/device_keeper.c	(revision 5f183dc4838c34c9d629c1c31e7eac82fd19c5e3)
+++ uspace/drv/uhci-hcd/utils/device_keeper.c	(revision 5f183dc4838c34c9d629c1c31e7eac82fd19c5e3)
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2011 Jan Vesely
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup drvusbuhci
+ * @{
+ */
+/** @file
+ * @brief UHCI driver
+ */
+#include <assert.h>
+#include <errno.h>
+
+#include "device_keeper.h"
+
+/*----------------------------------------------------------------------------*/
+void device_keeper_init(device_keeper_t *instance)
+{
+	assert(instance);
+	fibril_mutex_initialize(&instance->guard);
+	fibril_condvar_initialize(&instance->default_address_occupied);
+	instance->last_address = 0;
+	unsigned i = 0;
+	for (; i < USB_ADDRESS_COUNT; ++i) {
+		instance->devices[i].occupied = false;
+		instance->devices[i].handle = 0;
+	}
+}
+/*----------------------------------------------------------------------------*/
+void device_keeper_reserve_default(
+    device_keeper_t *instance, usb_speed_t speed)
+{
+	assert(instance);
+	fibril_mutex_lock(&instance->guard);
+	while (instance->devices[USB_ADDRESS_DEFAULT].occupied) {
+		fibril_condvar_wait(&instance->default_address_occupied,
+		    &instance->guard);
+	}
+	instance->devices[USB_ADDRESS_DEFAULT].occupied = true;
+	instance->devices[USB_ADDRESS_DEFAULT].speed = speed;
+	fibril_mutex_unlock(&instance->guard);
+}
+/*----------------------------------------------------------------------------*/
+void device_keeper_release_default(device_keeper_t *instance)
+{
+	assert(instance);
+	fibril_mutex_lock(&instance->guard);
+	instance->devices[USB_ADDRESS_DEFAULT].occupied = false;
+	fibril_mutex_unlock(&instance->guard);
+	fibril_condvar_signal(&instance->default_address_occupied);
+}
+/*----------------------------------------------------------------------------*/
+usb_address_t device_keeper_request(
+    device_keeper_t *instance, usb_speed_t speed)
+{
+	assert(instance);
+	fibril_mutex_lock(&instance->guard);
+
+	usb_address_t new_address = instance->last_address + 1;
+	while (instance->devices[new_address].occupied) {
+		if (new_address == instance->last_address) {
+			fibril_mutex_unlock(&instance->guard);
+			return ENOSPC;
+		}
+		if (new_address == USB11_ADDRESS_MAX)
+			new_address = 1;
+		++new_address;
+	}
+
+	assert(new_address != USB_ADDRESS_DEFAULT);
+	assert(instance->devices[new_address].occupied == false);
+	instance->devices[new_address].occupied = true;
+	instance->devices[new_address].speed = speed;
+	instance->last_address = new_address;
+	fibril_mutex_unlock(&instance->guard);
+	return new_address;
+}
+/*----------------------------------------------------------------------------*/
+void device_keeper_bind(
+    device_keeper_t *instance, usb_address_t address, devman_handle_t handle)
+{
+	assert(instance);
+	fibril_mutex_lock(&instance->guard);
+	assert(address > 0);
+	assert(address <= USB11_ADDRESS_MAX);
+	assert(instance->devices[address].occupied);
+	instance->devices[address].handle = handle;
+	fibril_mutex_unlock(&instance->guard);
+}
+/*----------------------------------------------------------------------------*/
+void device_keeper_release(device_keeper_t *instance, usb_address_t address)
+{
+	assert(instance);
+	assert(address > 0);
+	assert(address <= USB11_ADDRESS_MAX);
+
+	fibril_mutex_lock(&instance->guard);
+	assert(instance->devices[address].occupied);
+	instance->devices[address].occupied = false;
+	fibril_mutex_unlock(&instance->guard);
+}
+/*----------------------------------------------------------------------------*/
+usb_address_t device_keeper_find(
+    device_keeper_t *instance, devman_handle_t handle)
+{
+	assert(instance);
+	fibril_mutex_lock(&instance->guard);
+	usb_address_t address = 1;
+	while (address <= USB11_ADDRESS_MAX) {
+		if (instance->devices[address].handle == handle) {
+			fibril_mutex_unlock(&instance->guard);
+			return address;
+		}
+	}
+	fibril_mutex_unlock(&instance->guard);
+	return ENOENT;
+}
+/*----------------------------------------------------------------------------*/
+usb_speed_t device_keeper_speed(
+    device_keeper_t *instance, usb_address_t address)
+{
+	assert(instance);
+	assert(address >= 0);
+	assert(address <= USB11_ADDRESS_MAX);
+	assert(instance->devices[address].occupied);
+	return instance->devices[address].speed;
+}
+/**
+ * @}
+ */
Index: uspace/drv/uhci-hcd/utils/device_keeper.h
===================================================================
--- uspace/drv/uhci-hcd/utils/device_keeper.h	(revision 5f183dc4838c34c9d629c1c31e7eac82fd19c5e3)
+++ uspace/drv/uhci-hcd/utils/device_keeper.h	(revision 5f183dc4838c34c9d629c1c31e7eac82fd19c5e3)
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2011 Jan Vesely
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup drvusbuhci
+ * @{
+ */
+/** @file
+ * @brief UHCI driver
+ */
+#ifndef UTILS_DEVICE_KEEPER_H
+#define UTILS_DEVICE_KEEPER_H
+#include <devman.h>
+#include <fibril_synch.h>
+#include <usb/usb.h>
+
+#define USB_ADDRESS_COUNT (USB11_ADDRESS_MAX + 1)
+
+struct usb_device_info {
+	usb_speed_t speed;
+	bool occupied;
+	devman_handle_t handle;
+};
+
+typedef struct device_keeper {
+	struct usb_device_info devices[USB_ADDRESS_COUNT];
+	fibril_mutex_t guard;
+	fibril_condvar_t default_address_occupied;
+	usb_address_t last_address;
+} device_keeper_t;
+
+void device_keeper_init(device_keeper_t *instance);
+void device_keeper_reserve_default(
+    device_keeper_t *instance, usb_speed_t speed);
+void device_keeper_release_default(device_keeper_t *instance);
+
+usb_address_t device_keeper_request(
+    device_keeper_t *instance, usb_speed_t speed);
+void device_keeper_bind(
+    device_keeper_t *instance, usb_address_t address, devman_handle_t handle);
+void device_keeper_release(device_keeper_t *instance, usb_address_t address);
+usb_address_t device_keeper_find(
+    device_keeper_t *instance, devman_handle_t handle);
+
+usb_speed_t device_keeper_speed(
+    device_keeper_t *instance, usb_address_t address);
+#endif
+/**
+ * @}
+ */