term% cat index.txt NUSB(4) Kernel Interfaces Manual NUSB(4)
NAME
audio, disk, ether, kb, serial, ptp, usbd - Universal Serial Bus driv‐
ers
SYNOPSIS
nusb/audio devid
nusb/disk [ -d ] devid
nusb/ether [ -dD ] [ -t ethertype ] [ -a addr ] devid
nusb/kb [ -d ] devid
nusb/serial [ -d ] devid
nusb/ptp [ -dD ] devid
nusb/usbd [ -dD ]
DESCRIPTION
These programs drive USB devices of specific classes via usb(3). Usu‐
ally they are started by nusbrc(8) upon attachment of the device to the
bus. All drivers except usbd take the decimal usb devid of the device
they should handle as ther last argument. A driver's instance handles
only one device at a time.
Drivers that provide file systems make them available as shares under
/shr (see shr(3)) or /shr/usb (which is bound after /dev by nusbrc(8)).
Options -d and -D trigger debug diagnostics and file system debugging
diagnostics for most drivers. Repeating any one of these may increase
verbosity.
Hubs
Usbd enumerates the tree of USB hubs and configures the device on at‐
tachment. It provides a filesystem with the file usbevent (usually seen
as /dev/usbevent) which, when read, returns a 6 column, space separated
line of text, one for each event. The columns are: attach or detach
followed by addr vid did csp and hname . The addr is the decimal de‐
vice address assigned. Vid and did are formatted as 4 digit hexadeci‐
mal. Csp is the device class, subclass, protocol indentifier formatd
as 6 digit hexadecimal. Usbd assigns a stable device unique name based
on the device descriptor for hname . This information is read by nus‐
brc(8) and the addr and hname are passed to a suitable driver as devid
in the form addr:hname
Keyboards and mice
Kb supports USB keyboards and mice either as separate USB devices or as
a single combined USB device. Scan codes from the keyboard are sent to
/dev/kbin to let kbdfs(8) process them. Mouse events are sent to
/dev/mousein in the same way.
Disks
Disk configures and manages USB mass storage devices. It provides a
file system (usually seen under /dev) that includes one directory per
storage device, named sdUN[.M] in correspondence with the usb device
unique name and the storage unit number (or LUN). The LUN is omited for
single lun devices.
The storage device directory contains the usual files served by sd(3):
data, raw, and ctl.
The ctl file supplies the device geometry and partitions when read.
Ethernet
Ether handles USB ethernet devices. The file system provided is compat‐
ible to ether(3) and added to the share usbnet (see shr(3)) which is
bound after /net by nusbrc(8) so the device will appear as
/net/etherUN. Without specifying the -t option, the device is assumed
to be a CDC compliant ethernet communication device. Other devices
might require setting an explicit ethertype, such as rndis, smsc,
a88772 or a88178 (see nusbrc(8)). On devices that support it, the mac
address can be set using the -a addr option.
Serial and JTAG ports
Serial provides a file system (usually seen under /dev) that includes
one directory per USB serial port, named eiaUN or eiaUN[.M]. In this
directory there are two files, eiaU, similar to eiaN in uart(3), and
eiaUctl, which admits writes in the same format as eiaNctl in uart(3).
Reading from eiaUctl gives the serial port's settings in the same for‐
mat as eiaNstatus in uart(3). Options are similar to those of disk.
JTAG ports are similar but the files are named jtag and jtagctl.
Audio devices
Audio configures and manages a USB audio device. It implements a file
system, (normally seen under /dev) compatible to audio(3).
SOURCE
/sys/src/cmd/nusb
SEE ALSO
audio(3), ether(3), mouse(3), sd(3), uart(3), usb(3), shr(3), nus‐
brc(8), kbdfs(8)
BUGS
The various device drivers are generic USB drivers and may work only
for certain devices of each class.
USB ATA storage devices are not supported.
The serial driver works only for the Prolific chip and Ftdi, and con‐
trol of the dcd and dsr signals and some of the extra features are not
implemented. For Ftdi, only the Sheevaplug and Guruplug have been
tried. There is support for the EHCI debug port, but it loses bytes.
NUSB(4)