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NAME    [Toc]    [Back]

     ugen -- USB generic device support

SYNOPSIS    [Toc]    [Back]

     device ugen

DESCRIPTION    [Toc]    [Back]

     The ugen driver provides support for all USB devices that do not have a
     special driver.  It supports access to all parts of the device, but not
     in a way that is as convenient as a special purpose driver.

     There can be up to 127 USB devices connected to a USB bus.  Each USB
     device can have up to 16 endpoints.  Each of these endpoints will communicate
 in one of four different modes: control, isochronous, bulk, or
     interrupt.  Each of the endpoints will have a different device node.  The
     four least significant bits in the minor device number determines which
     endpoint the device accesses and the rest of the bits determines which
     USB device.

     If an endpoint address is used both for input and output the device can
     be opened for both read or write.

     To find out what endpoints that exist there are a series of ioctl(2)
     operation on the control endpoint that returns the USB descriptors of the
     device, configurations, interfaces, and endpoints.

     The control transfer mode can only happen on the control endpoint which
     is always endpoint 0.  The control endpoint accepts request and may
     respond with an answer to such request.  Control request are issued by
     ioctl(2) calls.

     The bulk transfer mode can be in or out depending on the endpoint.  To
     perform I/O on a bulk endpoint read(2) and write(2) should be used.  All
     I/O operations on a bulk endpoint are unbuffered.

     The interrupt transfer mode can be in or out depending on the endpoint.
     To perform I/O on an interrupt endpoint read(2) and write(2) should be
     used.  A moderate amount of buffering is done by the driver.

     All endpoints handle the following ioctl(2) calls:

	     Allow short read transfer.  Normally a transfer from the device
	     which is shorter than the request specified is reported as an

     USB_SET_TIMEOUT (int)
	     Set the timeout on the device operations, the time is specified
	     in milliseconds.  The value 0 is used to indicate that there is
	     no timeout.

     The control endpoint (endpoint 0) handles the following ioctl(2) calls:

     USB_GET_CONFIG (int)
	     Get the device configuration number.

     USB_SET_CONFIG (int)
	     Set the device into the given configuration number.

	     This operation can only be performed when the control endpoint is
	     the sole open endpoint.

     USB_GET_ALTINTERFACE (struct usb_alt_interface)
	     Get the alternative setting number for the interface with the
	     given index.  The uai_config_index is ignored in this call.

	     struct usb_alt_interface {
		     int     uai_config_index;
		     int     uai_interface_index;
		     int     uai_alt_no;

     USB_SET_ALTINTERFACE (struct usb_alt_interface)
	     Set the alternative setting to the given number in the interface
	     with the given index.  The uai_config_index is ignored in this

	     This operation can only be performed when no endpoints for the
	     interface are open.

     USB_GET_NO_ALT (struct usb_alt_interface)
	     Return the number of different alternate settings in the
	     uai_alt_no field.

     USB_GET_DEVICE_DESC (usb_device_descriptor_t)
	     Return the device descriptor.

     USB_GET_CONFIG_DESC (struct usb_config_desc)
	     Return the descriptor for the configuration with the given index.
	     For convenience the current configuration can be specified by

	     struct usb_config_desc {
		     int     ucd_config_index;
		     usb_config_descriptor_t ucd_desc;

     USB_GET_INTERFACE_DESC (struct usb_interface_desc)
	     Return the interface descriptor for an interface specified by its
	     configuration index, interface index, and alternative index.  For
	     convenience the current alternative can be specified by

	     struct usb_interface_desc {
		     int     uid_config_index;
		     int     uid_interface_index;
		     int     uid_alt_index;
		     usb_interface_descriptor_t uid_desc;

     USB_GET_ENDPOINT_DESC (struct usb_endpoint_desc)
	     Return the endpoint descriptor for the endpoint specified by its
	     configuration index, interface index, alternative index, and endpoint

	     struct usb_endpoint_desc {
		     int     ued_config_index;
		     int     ued_interface_index;
		     int     ued_alt_index;
		     int     ued_endpoint_index;
		     usb_endpoint_descriptor_t ued_desc;

     USB_GET_FULL_DESC (struct usb_full_desc)
	     Return all the descriptors for the given configuration.

	     struct usb_full_desc {
		     int     ufd_config_index;
		     u_int   ufd_size;
		     u_char  *ufd_data;
	     The ufd_data field should point to a memory area of the size
	     given in the ufd_size field.  The proper size can be determined
	     by first issuing a USB_GET_CONFIG_DESC and inspecting the
	     wTotalLength field.

     USB_GET_STRING_DESC (struct usb_string_desc)
	     Get a string descriptor for the given language ID and string

	     struct usb_string_desc {
		     int     usd_string_index;
		     int     usd_language_id;
		     usb_string_descriptor_t usd_desc;

     USB_DO_REQUEST (struct usb_ctl_request)
	     Send a USB request to the device on the control endpoint.	Any
	     data sent to/from the device is located at ucr_data.  The size of
	     the transferred data is determined from the ucr_request.  The
	     ucr_addr field is ignored in this call.  The ucr_flags field can
	     be used to flag that the request is allowed to be shorter than
	     the requested size, and the ucr_actlen will contain the actual
	     size on completion.

	     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 */
	     This is a dangerous operation in that it can perform arbitrary
	     operations on the device.	Some of the most dangerous (e.g.,
	     changing the device address) are not allowed.

     USB_GET_DEVICEINFO (struct usb_device_info)
	     Get an information summary for the device.  This call will not
	     issue any USB transactions.

     Note that there are two different ways of addressing configurations,
     interfaces, alternatives, and endpoints: by index or by number.  The
     index is the ordinal number (starting from 0) of the descriptor as presented
 by the device.  The number is the respective number of the entity
     as found in its descriptor.  Enumeration of descriptors use the index,
     getting and setting typically uses numbers.

     Example: all endpoints (except the control endpoint) for the current configuration
 can be found by iterating the interface_index from 0 to
     config_desc->bNumInterface-1 and for each of these iterating the
     endpoint_index from 0 to interface_desc->bNumEndpoints.  The config_index
     should set to USB_CURRENT_CONFIG_INDEX and alt_index should be set to

FILES    [Toc]    [Back]

     /dev/ugenN.EE  Endpoint EE of device N.

SEE ALSO    [Toc]    [Back]


HISTORY    [Toc]    [Back]

     The ugen driver appeared in NetBSD 1.4.

FreeBSD 5.2.1			 July 12, 1998			 FreeBSD 5.2.1
[ Back ]
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