Copyright (c) 1998 The NetBSD Foundation, Inc.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. 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.
3. All advertising materials mentioning features or use of this software
must display the following acknowledgement:
This product includes software developed by the NetBSD
Foundation, Inc. and its contributors.
4. Neither the name of The NetBSD Foundation nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
``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 FOUNDATION OR CONTRIBUTORS
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.
.Dd July 12, 1998 .Dt USB 4 .Os .Sh NAME .Nm usb .Nd introduction to USB support .Sh SYNOPSIS .Cd "uhci* at pci? function?" .Cd "ohci* at pci? function?" .Cd "usb* at uhci?" .Cd "usb* at ohci?" .Cd "uhub* at usb?" .Cd "uhub* at uhub? port ?" .Cd "XX* at uhub? port ?"
p .Sh INTRODUCTION .Nx provides machine-independent bus support and drivers for USB devices.
p The .Nx driver has three layers (like .Xr scsi 4 and .Xr pcmcia 4 ): the controller, the bus, and the device layer. The controller attaches to a physical bus (like .Xr pci 4 ). The USB bus attaches to the controller and the root hub attaches to the controller. Further devices, which includes further hubs, attach to other hubs. The attachment forms the same tree structure as the physical USB device tree. For each USB device there may be further drivers attached to it.
p The .Cm uhub device controls USB hubs and must always be present (since there is at least a root hub in any USB system).
p .Sh INTRODUCTION TO USB The USB is a 12Mb/s serial bus (1.5 Mb/s for low speed devices). Each USB bus has a host controller that is the master of the bus; all other devices on the bus only speak when spoken to.
p There can be up to 127 devices (apart from the host controller) on a bus each with its own address. The addresses are assigned dynamically by the host when the device is attached to the bus.
p Within each device there can be up to 16 endpoints. Each endpoint is individually addressed and the addresses are static. Each of these endpoints will communicate in one of four different modes: control, isochronous, bulk, or interrupt. A device always has at least one endpoint. This endpoint has address 0 and is a control endpoint and is used to give commands to and extract basic data such as descriptors from the device. Each endpoint, except control endpoints, is unidirectional.
p The endpoints in a device are grouped into interfaces. An interface is a logical unit within a device. E.g., a compound device with both a keyboard and a trackball would present one interface for each. An interface can sometimes be set into different modes, called alternate settings, which affects how it operates. Different alternate settings can have different endpoints within it.
p A device may operate in different configurations. Depending on the configuration the device may present different sets of endpoints and interfaces.
p
The USB controller has a device that supports
.Xr ioctl 2
to manipulate it.
.Sh SEE ALSO
.Xr pci 4 ,
.Xr uaudio 4 ,
.Xr ugen 4 ,
.Xr uhid 4 ,
.Xr ukbd 4 ,
.Xr ulpt 4 ,
.Xr ums 4 ,
.Xr usbd 8
.Sh HISTORY
The
.Nm
driver
appeared in
.Nx 1.4 .
Indexes created Sun Oct 12 05:10:08 GMT 2025