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

NAME
     usb - introduction to Universal Serial Bus support

SYNOPSIS
     # zaurus specific
     ohci0   at pxaip?
     # all architectures
     ehci*   at cardbus?
     uhci*   at cardbus?
     ohci*   at cardbus?
     ehci*   at pci?
     uhci*   at pci?
     ohci*   at pci?
     usb*    at ehci? flags 0x00
     usb*    at uhci? flags 0x00
     usb*    at ohci? flags 0x00
     uhub*   at usb?
     uhub*   at uhub?

     option    USBVERBOSE

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

DESCRIPTION
     OpenBSD provides machine-independent bus support and drivers for Univer-
     sal Serial Bus (USB) devices.

     The OpenBSD 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) or cardbus(4)).  The USB bus attaches to the
     controller and the root hub attaches to the USB bus.  Devices, which may
     include further hubs, attach to the root hub.  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 driver controls USB hubs and must always be present since there
     is at least one root hub in any USB system.

     The flags are used to specify if the devices on the USB bus should be
     probed early in the boot process.  If the flags are specified with a val-
     ue of 1, the USB bus will be probed when the USB host device is attached
     instead of waiting until kernel processes start running.

     OpenBSD provides support for the following devices.  Note that not all
     architectures support all devices.

   Storage devices
        umass(4)      USB Mass Storage Devices, e.g., external disk drives

   Wired network interfaces
        aue(4)        ADMtek AN986/ADM8511 Pegasus family 10/100 USB Ethernet
                      device
        axe(4)        ASIX Electronics AX88172/AX88178/AX88772 10/100/Gigabit
                      USB Ethernet device
        cdce(4)       USB Communication Device Class Ethernet device
        cue(4)        CATC USB-EL1201A USB Ethernet device
        kue(4)        Kawasaki LSI KL5KUSB101B USB Ethernet device
        mos(4)        MOSCHIP MCS7730/7830 10/100 USB 2.0 Ethernet device
        udav(4)       Davicom DM9601 10/100 USB Ethernet device
        ueagle(4)     Analog Devices Eagle ADSL modems
        url(4)        Realtek RTL8150L 10/100 USB Ethernet device
        urndis(4)     USB Remote NDIS Ethernet device

   Wireless network interfaces
        atu(4)        Atmel AT76C50x IEEE 802.11b wireless network device
        otus(4)       Atheros USB IEEE 802.11a/g/n wireless network device
        rum(4)        Ralink Technology USB IEEE 802.11a/b/g wireless network
                      device
        run(4)        Ralink Technology USB IEEE 802.11a/g/n wireless network
                      device
        uath(4)       Atheros USB IEEE 802.11a/b/g wireless network device
        ubt(4)        Bluetooth adapters
        upgt(4)       Conexant/Intersil PrismGT SoftMAC USB IEEE 802.11b/g
                      wireless network device
        ural(4)       Ralink Technology USB IEEE 802.11b/g wireless network
                      device
        urtw(4)       Realtek RTL8187L/RTL8187B USB IEEE 802.11b/g wireless
                      network device
        wi(4)         Intersil PRISM 2-3 IEEE 802.11b wireless network device
        zyd(4)        ZyDAS ZD1211/ZD1211B USB IEEE 802.11b/g wireless network
                      device

   Serial and parallel interfaces
        moscom(4)     MosChip Semiconductor MCS7703 based USB serial adapter
        uark(4)       Arkmicro Technologies ARK3116 based USB serial adapter
        ubsa(4)       Belkin USB serial adapter
        uchcom(4)     WinChipHead CH341/340 based USB serial adapter
        ucom(4)       USB tty support
        uftdi(4)      FTDI USB serial adapter
        uipaq(4)      iPAQ USB units
        ulpt(4)       USB printer support
        umct(4)       MCT USB-RS232 USB serial adapter
        umodem(4)     USB modem support
        umsm(4)       Qualcomm MSM modem device
        uplcom(4)     Prolific PL-2303 USB serial adapter
        uslcom(4)     Silicon Laboratories CP2101/CP2102 based USB serial
                      adapter
        uticom(4)     Texas Instruments TUSB3410 USB serial adapter
        uvisor(4)     USB Handspring Visor
        uvscom(4)     SUNTAC Slipper U VS-10U USB serial adapter

   Audio devices
        uaudio(4)     USB audio devices
        umidi(4)      USB MIDI devices
        urio(4)       Diamond Multimedia Rio MP3 players

   Video devices
        udl(4)        DisplayLink DL-120 / DL-160 USB display devices
        uvideo(4)     USB video devices

   Time receiver devices
        udcf(4)       Gude ADS Expert mouseCLOCK USB timedelta sensor
        umbg(4)       Meinberg Funkuhren USB5131 timedelta sensor

   Radio receiver devices
        udsbr(4)      D-Link DSB-R100 USB radio device

   Human Interface Devices
        tpms(4)       Apple touchpad mouse
        ucycom(4)     Cypress microcontroller based USB serial adapter
        uhid(4)       Generic driver for Human Interface Devices
        uhidev(4)     Base driver for all Human Interface Devices
        uhts(4)       USB HID touchscreen support
        ukbd(4)       USB keyboards that follow the boot protocol
        ums(4)        USB mouse devices
        uthum(4)      TEMPerHUM USB temperature and humidity sensor
        utrh(4)       USBRH temperature and humidity sensor

   Miscellaneous devices
        uberry(4)     Research In Motion Blackberry
        ugen(4)       USB generic device support
        uow(4)        Maxim/Dallas DS2490 USB 1-Wire adapter
        upl(4)        Prolific based host-to-host adapters
        uscanner(4)   USB scanner support
        usscanner(4)  SCSI-over-USB scanners
        uts(4)        USB touchscreen support
        uyap(4)       USB YAP phone firmware loader

INTRODUCTION TO USB
     There are different versions of the USB which provide different speeds.
     USB 2 operates at 480Mb/s, while USB versions 1 and 1.1 operate at 12
     Mb/s and 1.5 Mb/s for low speed devices.  Each USB has a host controller
     that is the master of the bus; all other devices on the bus only speak
     when spoken to.

     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 is a control endpoint at address 0 and is used to give com-
     mands to the device 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-
     faces.

     Each device located on a hub has several config(8) locators:

     port           Number of the port on closest upstream hub.
     configuration  Configuration the device must be in for this driver to at-
                    tach.  This locator does not set the configuration; it is
                    iterated by the bus enumeration.
     interface      Interface number within a device that an interface driver
                    attaches to.
     vendor         16-bit vendor ID of the device.
     product        16-bit product ID of the device.
     release        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 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 interfaces 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-
          tach.

USB CONTROLLER INTERFACE
     Use the following to get access to the USB specific structures and de-
     fines:

     #include <dev/usb/usb.h>

     The /dev/usbN device 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 con-
     troller 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 udi_addr field should be filled before the
             call and the other fields will be filled by information about the
             device on that address.  Should no such device exist, an error is
             reported.

             #define USB_MAX_DEVNAMES 4
             #define USB_MAX_DEVNAMELEN 16
             struct usb_device_info {
                     u_int8_t        udi_bus;
                     u_int8_t        udi_addr;       /* device address */
                     usb_event_cookie_t udi_cookie;
                     char            udi_product[USB_MAX_STRING_LEN];
                     char            udi_vendor[USB_MAX_STRING_LEN];
                     char            udi_release[8];
                     u_int16_t       udi_productNo;
                     u_int16_t       udi_vendorNo;
                     u_int16_t       udi_releaseNo;
                     u_int8_t        udi_class;
                     u_int8_t        udi_subclass;
                     u_int8_t        udi_protocol;
                     u_int8_t        udi_config;
                     u_int8_t        udi_speed;
             #define USB_SPEED_LOW  1
             #define USB_SPEED_FULL 2
             #define USB_SPEED_HIGH 3
                     int             udi_power;      /* power consumption */
                     int             udi_nports;
                     char            udi_devnames[USB_MAX_DEVNAMES]
                                         [USB_MAX_DEVNAMELEN];
                     u_int8_t        udi_ports[16];  /* hub only */
             #define USB_PORT_ENABLED 0xff
             #define USB_PORT_SUSPENDED 0xfe
             #define USB_PORT_POWERED 0xfd
             #define USB_PORT_DISABLED 0xfc
             };

             The udi_bus field contains the device unit number of the device.

             The udi_product, udi_vendor, and udi_release fields contain self-
             explanatory descriptions of the device.  The udi_productNo,
             udi_vendorNo, and udi_releaseNo fields contain numeric identi-
             fiers for the device.

             The udi_class and udi_subclass fields contain the device class
             and subclass.

             The udi_config field shows the current configuration of the de-
             vice.

             The udi_protocol field contains the device protocol as given from
             the device.

             The udi_speed field contains the speed of the device.

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

             The udi_devnames field contains the names and instance numbers of
             the device drivers for the devices attached to this device.

             If the device is a hub, the udi_nports field is non-zero and the
             udi_ports field contains the addresses of the connected devices.
             If no device is connected to a port, one of the USB_PORT_* values
             indicates its status.

     USB_DEVICESTATS struct usb_device_stats *
             This command retrieves statistics about the controller.

             struct usb_device_stats {
                     u_long  uds_requests[4];
             };

             The uds_requests field is indexed by the transfer kind, i.e.
             UE_*, and indicates how many transfers of each kind have been
             completed 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 usb_ctl_request structure has the following definition:

             typedef struct {
                     uByte           bmRequestType;
                     uByte           bRequest;
                     uWord           wValue;
                     uWord           wIndex;
                     uWord           wLength;
             } __packed usb_device_request_t;

             struct usb_ctl_request {
                     int     ucr_addr;
                     usb_device_request_t ucr_request;
                     void    *ucr_data;
                     int     ucr_flags;
             #define USBD_SHORT_XFER_OK 0x04 /* allow short reads */
                     int     ucr_actlen;     /* actual length transferred */
             };

             The ucr_addr field identifies the device on which to perform the
             request.  The ucr_request field identifies parameters of the re-
             quest, such as length and type.  The ucr_data field contains the
             location where data will be read from or written to.  The
             ucr_flags field specifies options for the request, and the
             ucr_actlen field contains the actual length transferred as the
             result of the request.

     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 accessed by the UGETW(field) and USETW(field, value)
     macros and double word (32-bit) sized fields must be accessed by the
     UGETDW(field) and USETDW(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).

SEE ALSO
     usbhidaction(1), usbhidctl(1), ioctl(2), ehci(4), ohci(4), uhci(4),
     config(8), usbdevs(8)

     The USB specifications can be found at:

           http://www.usb.org/developers/docs/

HISTORY
     The usb driver appeared in OpenBSD 2.6.

OpenBSD 4.7                      March 2, 2010                               6
