4a98da2cc0
page to be clearer. PR: docs/175560 Submitted by: Andreas Gustafsson <gson gson.org> MFC after: 3 days
312 lines
9.1 KiB
Groff
312 lines
9.1 KiB
Groff
.\" $NetBSD: ugen.4,v 1.13 2001/09/11 22:52:54 wiz Exp $
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.\"
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.\" Copyright (c) 1999 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Lennart Augustsson.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd May 16, 2014
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.Dt UGEN 4
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.Os
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.Sh NAME
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.Nm ugen
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.Nd USB generic device support
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.Sh SYNOPSIS
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.Nm
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is integrated into the
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.Xr usb 4
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kernel module.
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.Sh DESCRIPTION
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The
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.Nm
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driver provides support for all USB devices that do not have
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a special driver.
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It supports access to all parts of the device,
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but not in a way that is as convenient as a special purpose driver.
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.Pp
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There can be up to 127 USB devices connected to a USB bus.
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Each USB device can have up to 16 endpoints.
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Each of these endpoints
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will communicate in one of four different modes: control, isochronous,
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bulk, or interrupt.
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Each of the endpoints will have a different
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device node.
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The four least significant bits in the minor device
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number determine which endpoint the device accesses, and the rest
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of the bits determine which USB device.
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.Pp
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If an endpoint address is used both for input and output, the device
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can be opened for both read or write.
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.Pp
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To find out which endpoints exist, there are a series of
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.Xr ioctl 2
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operations on the control endpoint that return the USB descriptors
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of the device, configurations, interfaces, and endpoints.
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.Pp
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The control transfer mode can only happen on the control endpoint
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which is always endpoint 0.
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The control endpoint accepts a request
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and may respond with an answer to such a request.
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Control requests
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are issued by
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.Xr ioctl 2
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calls.
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.\" .Pp
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.\" The isochronous transfer mode can be in or out depending on the
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.\" endpoint.
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.\" To perform I/O on an isochronous endpoint
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.\" .Xr read 2
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.\" and
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.\" .Xr write 2
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.\" should be used.
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.\" Before any I/O operations can take place the transfer rate in
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.\" bytes/second has to be set.
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.\" This is done with
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.\" .Xr ioctl 2
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.\" .Dv USB_SET_ISO_RATE .
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.\" Performing this call sets up a buffer corresponding to
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.\" about 1 second of data.
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.Pp
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The bulk transfer mode can be in or out depending on the
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endpoint.
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To perform I/O on a bulk endpoint
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.Xr read 2
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and
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.Xr write 2
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should be used.
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All I/O operations on a bulk endpoint are unbuffered.
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.Pp
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The interrupt transfer mode can be in or out depending on the
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endpoint.
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To perform I/O on an interrupt endpoint
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.Xr read 2
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and
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.Xr write 2
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should be used.
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A moderate amount of buffering is done
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by the driver.
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.Pp
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All endpoints handle the following
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.Xr ioctl 2
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calls:
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.Bl -tag -width indent
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.It Dv USB_SET_SHORT_XFER Pq Vt int
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Allow short read transfer.
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Normally a transfer from the device
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which is shorter than the request specified is reported as an
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error.
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.It Dv USB_SET_TIMEOUT Pq Vt int
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Set the timeout on the device operations
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The time is specified in milliseconds.
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The value 0 is used to indicate that there is
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no timeout.
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.El
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.Pp
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The control endpoint (endpoint 0) handles the following
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.Xr ioctl 2
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calls:
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.Bl -tag -width indent
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.It Dv USB_GET_CONFIG Pq Vt int
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Get the device configuration number.
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.It Dv USB_SET_CONFIG Pq Vt int
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Set the device into the given configuration number.
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.Pp
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This operation can only be performed when the control endpoint
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is the sole open endpoint.
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.It Dv USB_GET_ALTINTERFACE Pq Vt "struct usb_alt_interface"
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Get the alternative setting number for the interface with the given
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index.
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The
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.Va uai_config_index
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is ignored in this call.
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.Bd -literal
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struct usb_alt_interface {
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int uai_config_index;
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int uai_interface_index;
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int uai_alt_no;
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};
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.Ed
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.It Dv USB_SET_ALTINTERFACE Pq Vt "struct usb_alt_interface"
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Set the alternative setting to the given number in the interface with the
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given index.
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The
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.Va uai_config_index
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is ignored in this call.
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.Pp
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This operation can only be performed when no endpoints for the interface
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are open.
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.It Dv USB_GET_NO_ALT Pq Vt "struct usb_alt_interface"
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Return the number of different alternate settings in the
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.Va uai_alt_no
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field.
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.It Dv USB_GET_DEVICE_DESC Pq Vt usb_device_descriptor_t
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Return the device descriptor.
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.It Dv USB_GET_CONFIG_DESC Pq Vt "struct usb_config_desc"
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Return the descriptor for the configuration with the given index.
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For convenience, the current configuration can be specified by
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.Dv USB_CURRENT_CONFIG_INDEX .
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.Bd -literal
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struct usb_config_desc {
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int ucd_config_index;
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usb_config_descriptor_t ucd_desc;
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};
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.Ed
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.It Dv USB_GET_INTERFACE_DESC Pq Vt "struct usb_interface_desc"
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Return the interface descriptor for an interface specified by its
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configuration index, interface index, and alternative index.
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For convenience, the current alternative can be specified by
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.Dv USB_CURRENT_ALT_INDEX .
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.Bd -literal
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struct usb_interface_desc {
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int uid_config_index;
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int uid_interface_index;
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int uid_alt_index;
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usb_interface_descriptor_t uid_desc;
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};
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.Ed
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.It Dv USB_GET_ENDPOINT_DESC Pq Vt "struct usb_endpoint_desc"
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Return the endpoint descriptor for the endpoint specified by its
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configuration index, interface index, alternative index, and
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endpoint index.
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.Bd -literal
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struct usb_endpoint_desc {
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int ued_config_index;
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int ued_interface_index;
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int ued_alt_index;
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int ued_endpoint_index;
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usb_endpoint_descriptor_t ued_desc;
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};
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.Ed
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.It Dv USB_GET_FULL_DESC Pq Vt "struct usb_full_desc"
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Return all the descriptors for the given configuration.
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.Bd -literal
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struct usb_full_desc {
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int ufd_config_index;
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u_int ufd_size;
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u_char *ufd_data;
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};
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.Ed
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The
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.Va ufd_data
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field should point to a memory area of the size given in the
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.Va ufd_size
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field.
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The proper size can be determined by first issuing a
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.Dv USB_GET_CONFIG_DESC
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and inspecting the
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.Va wTotalLength
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field.
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.It Dv USB_GET_STRING_DESC Pq Vt "struct usb_string_desc"
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Get a string descriptor for the given language ID and
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string index.
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.Bd -literal
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struct usb_string_desc {
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int usd_string_index;
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int usd_language_id;
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usb_string_descriptor_t usd_desc;
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};
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.Ed
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.It Dv USB_DO_REQUEST Pq Vt "struct usb_ctl_request"
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Send a USB request to the device on the control endpoint.
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Any data sent to/from the device is located at
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.Va ucr_data .
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The size of the transferred data is determined from the
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.Va ucr_request .
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The
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.Va ucr_addr
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field is ignored in this call.
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The
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.Va ucr_flags
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field can be used to flag that the request is allowed to
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be shorter than the requested size, and
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.Va ucr_actlen
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will contain the actual size on completion.
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.Bd -literal
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struct usb_ctl_request {
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int ucr_addr;
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usb_device_request_t ucr_request;
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void *ucr_data;
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int ucr_flags;
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#define USBD_SHORT_XFER_OK 0x04 /* allow short reads */
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int ucr_actlen; /* actual length transferred */
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};
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.Ed
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This is a dangerous operation in that it can perform arbitrary operations
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on the device.
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Some of the most dangerous (e.g., changing the device
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address) are not allowed.
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.It Dv USB_GET_DEVICEINFO Pq Vt "struct usb_device_info"
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Get an information summary for the device.
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This call will not issue any USB transactions.
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.El
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.Pp
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Note that there are two different ways of addressing configurations,
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interfaces, alternatives, and endpoints: by index or by number.
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The index is the ordinal number (starting from 0) of the descriptor
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as presented by the device.
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The number is the respective number of
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the entity as found in its descriptor.
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Enumeration of descriptors
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uses the index, getting and setting typically uses numbers.
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.Pp
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Example:
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all endpoints (except the control endpoint) for the current configuration
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can be found by iterating the
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.Va interface_index
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from 0 to
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.Va config_desc->bNumInterface Ns \-1
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and for each of these, iterating the
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.Va endpoint_index
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from 0 to
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.Va interface_desc->bNumEndpoints .
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The
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.Va config_index
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should be set to
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.Dv USB_CURRENT_CONFIG_INDEX
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and
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.Va alt_index
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should be set to
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.Dv USB_CURRENT_ALT_INDEX .
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.Sh FILES
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.Bl -tag -width ".Pa /dev/ugen Ns Ar N Ns Pa \&. Ns Ar E" -compact
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.It Pa /dev/ugen Ns Ar N Ns Pa \&. Ns Ar E
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Endpoint
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.Ar E
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of device
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.Ar N .
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.El
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.Sh SEE ALSO
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.Xr usb 4
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.Sh HISTORY
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The
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.Nm
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driver
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appeared in
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.Nx 1.4 .
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.\" .Sh BUGS
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.\" The driver is not yet finished; there is no access to isochronous endpoints.
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