USB(4)                    NetBSD Programmer's Manual                    USB(4)

     usb - Universal Serial Bus driver

     ehci*   at cardbus? dev ? function ?
     ehci*   at pci? dev ? function ?
     ohci*   at cardbus? dev ? function ?
     ohci*   at pci? dev ? function ?
     uhci*   at pci? dev ? function ?
     usb*    at ehci? flags X
     usb*    at ohci? flags X
     usb*    at uhci? flags X
     uhub*   at usb?
     uhub*   at uhub? port ? configuration ? interface ? vendor ? product ?
           release ?
     XX*     at uhub? port ? configuration ? interface ? vendor ? product ?
           release ?

     #include <dev/usb/usb.h>
     #include <dev/usb/usbhid.h>

     NetBSD provides machine-independent bus support and drivers for USB de-

     The NetBSD usb driver has three layers (like scsi(4) and pcmcia(4)): the
     controller, the bus, and the device layer.  The controller attaches to a
     physical bus (like pci(4)).  The USB bus attaches to the controller and
     the root hub attaches to the controller.  Further devices, which may in-
     clude 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 additional drivers attached to it.

     The uhub device controls USB hubs and must always be present since there
     is at least a root hub in any USB system.

     The flags argument to the usb device affects the order in which the de-
     vice detection happens during cold boot.  Normally, only the USB host
     controller and the usb device are detected during the autoconfiguration
     when the machine is booted.  The rest of the devices are detected once
     the system becomes functional and the kernel thread for the usb device is
     started.  Sometimes it is desirable to have a device detected early in
     the boot process, e.g., the console keyboard.  To achieve this use a
     flags value of 1.

     NetBSD includes machine-independent USB drivers, sorted by driver name:

           aue        driver for ADMtek AN986 Pegasus USB Ethernet.

           cue        driver for CATC USB-EL1201A USB Ethernet.

           kue        driver for Kawasaki LSI KL5KUSB101B USB Ethernet.

           url        driver for Realtek RTL8150L USB Ethernet.

           uaudio     driver for audio devices.

           udsbr      driver for D-Link DSB-R100 USB radio.

           uftdi      driver for FTDI based serial adapters.

           ugen       generic driver for USB devices.

           uhidev     top level HID driver.

           uhid       generic driver for Human Interface Devices.

           uirda      driver for USB-IrDA bridges.

           ukbd       keyboard driver.

           ulpt       printer driver.

           umass      driver for mass storage devices, such as disks.

           umidi      driver for MIDI devices.

           umodem     driver for communication devices that use the Abstract
                      Control Model.

           ums        mouse driver.

           upl        driver for Prolific host-to-host adapter.

           uplcom     driver for Prolific 2303 serial adapter.

           umct       driver for MCT USB-RS232 serial adapter.

           urio       driver for the Diamond Rio 500 MP3 player.

           uscanner   driver for some USB scanners.

           usscanner  driver for some SCSI-over-USB scanners.

           ustir      driver for SigmaTel STIr4200 USB-IrDA bridges.

           uvisor     Handspring Visor driver.

           uvscom     driver for SUNTAC Slipper U VS-10U serial adapter.

     The USB 1.x is a 12 Mb/s serial bus with 1.5 Mb/s for low speed devices.
     USB 2.x handles 480 Mb/s.  Each USB has a host controller that is the
     master of the bus; all other devices on the bus only speak when spoken

     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 each device is attached to the bus.

     Within each device there can be up to 16 endpoints.  Each endpoint is in-
     dividually addressed and the addresses are static.  Each of these end-
     points will communicate in one of four different modes: control,
     isochronous, bulk, or interrupt.  A device always has at least one end-
     point.  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.

     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 key-
     board 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.

     A device may operate in different configurations.  Depending on the con-
     figuration the device may present different sets of endpoints and inter-

     Each device located on a hub has several config(8) locators:
     port       this is the number of the port on closest upstream hub.
                this is the configuration the device must be in for this driv-
                er to attach.  This locator does not set the configuration; it
                is iterated by the bus enumeration.
     interface  this is the interface number within a device that an interface
                driver attaches to.
     vendor     this is the 16 bit vendor id of the device.
     product    this is the 16 bit product id of the device.
     release    this is the 16 bit release (revision) number of the device.
     The first locator can be used to pin down a particular device according
     to its physical position in the device tree.  The last three locators can
     be used to pin down a particular device according to what device it actu-
     ally is.

     The bus enumeration of the USB bus proceeds in several steps:

     1.   Any device specific driver can to attach to the device.

     2.   If none is found, any device class specific driver can attach.

     3.   If none is found, all configurations are iterated over.  For each
          configuration all the interface are iterated over and interface
          drivers can attach.  If any interface driver attached in a certain
          configuration the iteration over configurations is stopped.

     4.   If still no drivers have been found, the generic USB driver can at-

     Use the following to get access to the USB specific structures and de-

     #include <sys/dev/usb.h>

     The /dev/usbN can be opened and a few operations can be performed on it.
     The poll(2) system call will say that I/O is possible on the controller
     device when a USB device has been connected or disconnected to the bus.

     The following ioctl(2) commands are supported on the controller device:

     USB_DEVICEINFO struct usb_device_info
             This command can be used to retrieve some information about a de-
             vice on the bus.  The addr field should be filled before the call
             and the other fields will be filled by information about the de-
             vice on that address.  Should no such device exist an error is

             struct usb_device_info {
                     u_int8_t        bus;
                     u_int8_t        addr;
                     usb_event_cookie_t cookie;
                     char            product[USB_MAX_STRING_LEN];
                     char            vendor[USB_MAX_STRING_LEN];
                     char            release[8];
                     u_int16_t       productNo;
                     u_int16_t       vendorNo;
                     u_int16_t       releaseNo;
                     u_int8_t        class;
                     u_int8_t        subclass;
                     u_int8_t        protocol;
                     u_int8_t        config;
                     u_int8_t        lowspeed;
                     int             power;
                     int             nports;
                     char            devnames[USB_MAX_DEVNAMES][USB_MAX_DEVNAMELEN];
                     u_int8_t        ports[16];
             #define USB_PORT_ENABLED 0xff
             #define USB_PORT_SUSPENDED 0xfe
             #define USB_PORT_POWERED 0xfd
             #define USB_PORT_DISABLED 0xfc

             The product, vendor, and release fields contain self-explanatory
             descriptions of the device.

             The class field contains the device class.

             The config field shows the current configuration of the device.

             The lowspeed field is set if the device is a USB low speed de-

             The power field shows the power consumption in milli-amps drawn
             at 5 volts, or zero if the device is self powered.

             If the device is a hub the nports field is non-zero and the ports
             field contains the addresses of the connected devices.  If no de-
             vice is connected to a port one of the USB_PORT_* values indi-
             cates its status.

     USB_DEVICESTATS struct usb_device_stats
             This command retrieves statistics about the controller.

             struct usb_device_stats {
                     u_long  requests[4];

             The requests field is indexed by the transfer kind, i.e.  UE_*,
             and indicates how many transfers of each kind that has been com-
             pleted by the controller.

     USB_REQUEST struct usb_ctl_request
             This command can be used to execute arbitrary requests on the
             control pipe.  This is DANGEROUS and should be used with great
             care since it can destroy the bus integrity.

     The include file <dev/usb/usb.h> contains definitions for the types used
     by the various ioctl(2) calls.  The naming convention of the fields for
     the various USB descriptors exactly follows the naming in the USB speci-
     fication.  Byte sized fields can be accessed directly, but word (16 bit)
     sized fields must be access by the UGETW(field) and USETW(field, value)
     macros to handle byte order and alignment properly.

     The include file <dev/usb/usbhid.h> similarly contains the definitions
     for Human Interface Devices (HID).

     All USB events are reported via the /dev/usb device.  This devices can be
     opened for reading and each read(2) will yield an event record (if some-
     thing has happened).  The poll(2) system call can be used to determine if
     an event record is available for reading.

     The event record has the following definition:

     struct usb_event {
             int                                 ue_type;
             struct timespec                     ue_time;
             union {
                     struct {
                             int                 ue_bus;
                     } ue_ctrlr;
                     struct usb_device_info      ue_device;
                     struct {
                             usb_event_cookie_t  ue_cookie;
                             char                ue_devname[16];
                     } ue_driver;
             } u;
     The ue_type field identifies the type of event that is described.  The
     possible events are attach/detach of a host controller, a device, or a
     device driver.  The union contains information pertinent to the different
     types of events.
     The ue_bus contains the number of the USB bus for host controller events.
     The ue_device record contains information about the device in a device
     event event.
     The ue_cookie is an opaque value that uniquely determines which which de-
     vice a device driver has been attached to (i.e., it equals the cookie
     value in the device that the driver attached to).  The ue_devname con-
     tains the name of the device (driver) as seen in, e.g., kernel messages.

     Note that that there is a separation between device and device driver
     events.  A device event is generated when a physical USB device is at-
     tached or detached.  A single USB device may have zero, one, or many de-
     vice drivers associated with it.

     The USB specifications can be found at:

     usb(3), aue(4), cardbus(4), cue(4), ehci(4), kue(4), ohci(4), pci(4),
     uaudio(4), ucom(4), udsbr(4), ugen(4), uhci(4), uhid(4), uhidev(4),
     uirda(4), ukbd(4), ulpt(4), umass(4), umidi(4), ums(4), upl(4), url(4),
     urio(4), uscanner(4), usscanner(4), ustir(4), uvisor(4), usbdevs(8)

     The usb driver appeared in NetBSD 1.4.

     There should be a serial number locator, but NetBSD does not have string
     valued locators.

NetBSD 1.6                       July 12, 1998                               5

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