186 lines
5.0 KiB
Groff
186 lines
5.0 KiB
Groff
.\" Copyright (c) 1997, 1998 Nick Hibma <n_hibma@FreeBSD.org>
|
|
.\" Copyright (c) 2008 Hans Petter Selasky. 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd November 26, 2013
|
|
.Dt USB 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm usb
|
|
.Nd Universal Serial Bus
|
|
.Sh SYNOPSIS
|
|
To compile this driver into the kernel,
|
|
place the following line in your
|
|
kernel configuration file:
|
|
.Bd -ragged -offset indent
|
|
.Cd "device usb"
|
|
.Ed
|
|
.Pp
|
|
Alternatively, to load the driver as a
|
|
module at boot time, place the following line in
|
|
.Xr loader.conf 5 :
|
|
.Bd -literal -offset indent
|
|
usb_load="YES"
|
|
.Ed
|
|
.Sh USERLAND PROGRAMMING
|
|
USB functions can be accessed from userland through the libusb library.
|
|
See
|
|
.Xr libusb 3
|
|
for more information.
|
|
.Sh DESCRIPTION
|
|
.Fx
|
|
provides machine-independent bus support and drivers for
|
|
.Tn USB
|
|
devices in host and device side mode.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
driver has three layers:
|
|
.Bl -tag -width 6n -offset indent
|
|
.It USB Controller (Bus)
|
|
.It USB Device
|
|
.It USB Driver
|
|
.El
|
|
.Pp
|
|
The controller attaches to a physical bus
|
|
like
|
|
.Xr pci 4 .
|
|
The
|
|
.Tn USB
|
|
bus attaches to the controller, and the root hub attaches
|
|
to the controller.
|
|
Any devices attached to the bus will attach to the root hub
|
|
or another hub attached to the
|
|
.Tn USB
|
|
bus.
|
|
.Pp
|
|
The
|
|
.Nm uhub
|
|
device will always be present as it is needed for the
|
|
root hub.
|
|
.Sh INTRODUCTION TO USB
|
|
The
|
|
.Tn USB
|
|
is a system where external devices can be connected to a PC.
|
|
The most common USB speeds are:
|
|
.Bl -tag -width 6n -offset indent
|
|
.It Low Speed (1.5MBit/sec)
|
|
.It Full Speed (12MBit/sec)
|
|
.It High Speed (480MBit/sec)
|
|
.El
|
|
.Pp
|
|
Each
|
|
.Tn USB
|
|
has a USB controller that is the master of the bus.
|
|
The physical communication is simplex which means the host controller only communicates with one USB device at a time.
|
|
.Pp
|
|
There can be up to 127 devices connected to an USB HUB tree.
|
|
The addresses are assigned
|
|
dynamically by the host when each device is attached to the bus.
|
|
.Pp
|
|
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:
|
|
.Em control , isochronous , bulk ,
|
|
or
|
|
.Em 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 the control endpoint, is unidirectional.
|
|
.Pp
|
|
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.
|
|
.Pp
|
|
A device may operate in different configurations.
|
|
Depending on the
|
|
configuration, the device may present different sets of endpoints
|
|
and interfaces.
|
|
.Pp
|
|
The bus enumeration of the
|
|
.Tn USB
|
|
bus proceeds in several steps:
|
|
.Bl -enum
|
|
.It
|
|
Any interface specific driver can attach to the device.
|
|
.It
|
|
If none is found, generic interface class drivers can attach.
|
|
.El
|
|
.Sh SEE ALSO
|
|
The
|
|
.Tn USB
|
|
specifications can be found at:
|
|
.Pp
|
|
.D1 Pa http://www.usb.org/developers/docs/
|
|
.Pp
|
|
.Xr libusb 3 ,
|
|
.Xr usbdi 4 ,
|
|
.Xr aue 4 ,
|
|
.Xr axe 4 ,
|
|
.Xr axge 4 ,
|
|
.Xr cue 4 ,
|
|
.Xr ehci 4 ,
|
|
.Xr kue 4 ,
|
|
.Xr mos 4 ,
|
|
.Xr ohci 4 ,
|
|
.Xr pci 4 ,
|
|
.Xr rue 4 ,
|
|
.Xr ucom 4 ,
|
|
.Xr udav 4 ,
|
|
.Xr uhci 4 ,
|
|
.Xr uhid 4 ,
|
|
.Xr ukbd 4 ,
|
|
.Xr ulpt 4 ,
|
|
.Xr umass 4 ,
|
|
.Xr ums 4 ,
|
|
.Xr uplcom 4 ,
|
|
.Xr urio 4 ,
|
|
.Xr uvscom 4 ,
|
|
.Xr usbconfig 8 ,
|
|
.Xr xhci 4
|
|
.Sh STANDARDS
|
|
The
|
|
.Nm
|
|
module complies with the USB 2.0 standard.
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
module has been inspired by the
|
|
.Nx
|
|
USB stack initially written by
|
|
.An Lennart Augustsson .
|
|
The
|
|
.Nm
|
|
module was written by
|
|
.An Hans Petter Selasky Aq Mt hselasky@FreeBSD.org .
|