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<table class="head">
<tr>
<td class="head-ltitle">UGEN(4)</td>
<td class="head-vol">Device Drivers Manual</td>
<td class="head-rtitle">UGEN(4)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">ugen</code> — <span class="Nd">USB generic
device support</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<table class="Nm">
<tr>
<td><code class="Nm">ugen</code></td>
<td>is integrated into the <a class="Xr">usb(4)</a> kernel module.</td>
</tr>
</table>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">ugen</code> 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.</p>
<p class="Pp">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 determine which endpoint
the device accesses, and the rest of the bits determine which USB
device.</p>
<p class="Pp">If an endpoint address is used both for input and output, the
device can be opened for both read or write.</p>
<p class="Pp">To find out which endpoints exist, there are a series of
<a class="Xr">ioctl(2)</a> operations on the control endpoint that return
the USB descriptors of the device, configurations, interfaces, and
endpoints.</p>
<p class="Pp">The control transfer mode can only happen on the control endpoint
which is always endpoint 0. The control endpoint accepts a request and may
respond with an answer to such a request. Control requests are issued by
<a class="Xr">ioctl(2)</a> calls.</p>
<p class="Pp">The bulk transfer mode can be in or out depending on the endpoint.
To perform I/O on a bulk endpoint <a class="Xr">read(2)</a> and
<a class="Xr">write(2)</a> should be used. All I/O operations on a bulk
endpoint are unbuffered.</p>
<p class="Pp">The interrupt transfer mode can be in or out depending on the
endpoint. To perform I/O on an interrupt endpoint <a class="Xr">read(2)</a>
and <a class="Xr">write(2)</a> should be used. A moderate amount of
buffering is done by the driver.</p>
<p class="Pp">All endpoints handle the following <a class="Xr">ioctl(2)</a>
calls:</p>
<dl class="Bl-tag">
<dt id="USB_SET_SHORT_XFER"><a class="permalink" href="#USB_SET_SHORT_XFER"><code class="Dv">USB_SET_SHORT_XFER</code></a>
(<var class="Vt">int</var>)</dt>
<dd>Allow short read transfer. Normally a transfer from the device which is
shorter than the request specified is reported as an error.</dd>
<dt id="USB_SET_TIMEOUT"><a class="permalink" href="#USB_SET_TIMEOUT"><code class="Dv">USB_SET_TIMEOUT</code></a>
(<var class="Vt">int</var>)</dt>
<dd>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.</dd>
</dl>
<p class="Pp">The control endpoint (endpoint 0) handles the following
<a class="Xr">ioctl(2)</a> calls:</p>
<dl class="Bl-tag">
<dt id="USB_GET_CONFIG"><a class="permalink" href="#USB_GET_CONFIG"><code class="Dv">USB_GET_CONFIG</code></a>
(<var class="Vt">int</var>)</dt>
<dd>Get the device configuration number.</dd>
<dt id="USB_SET_CONFIG"><a class="permalink" href="#USB_SET_CONFIG"><code class="Dv">USB_SET_CONFIG</code></a>
(<var class="Vt">int</var>)</dt>
<dd>Set the device into the given configuration number.
<p class="Pp">This operation can only be performed when the control endpoint
is the sole open endpoint.</p>
</dd>
<dt id="USB_GET_ALTINTERFACE"><a class="permalink" href="#USB_GET_ALTINTERFACE"><code class="Dv">USB_GET_ALTINTERFACE</code></a>
(<var class="Vt">struct usb_alt_interface</var>)</dt>
<dd>Get the alternative setting number for the interface with the given index.
The <var class="Va">uai_config_index</var> is ignored in this call.
<div class="Bd Pp Li">
<pre>struct usb_alt_interface {
int uai_config_index;
int uai_interface_index;
int uai_alt_no;
};</pre>
</div>
</dd>
<dt id="USB_SET_ALTINTERFACE"><a class="permalink" href="#USB_SET_ALTINTERFACE"><code class="Dv">USB_SET_ALTINTERFACE</code></a>
(<var class="Vt">struct usb_alt_interface</var>)</dt>
<dd>Set the alternative setting to the given number in the interface with the
given index. The <var class="Va">uai_config_index</var> is ignored in this
call.
<p class="Pp">This operation can only be performed when no endpoints for the
interface are open.</p>
</dd>
<dt id="USB_GET_NO_ALT"><a class="permalink" href="#USB_GET_NO_ALT"><code class="Dv">USB_GET_NO_ALT</code></a>
(<var class="Vt">struct usb_alt_interface</var>)</dt>
<dd>Return the number of different alternate settings in the
<var class="Va">uai_alt_no</var> field.</dd>
<dt id="USB_GET_DEVICE_DESC"><a class="permalink" href="#USB_GET_DEVICE_DESC"><code class="Dv">USB_GET_DEVICE_DESC</code></a>
(<var class="Vt">usb_device_descriptor_t</var>)</dt>
<dd>Return the device descriptor.</dd>
<dt id="USB_GET_CONFIG_DESC"><a class="permalink" href="#USB_GET_CONFIG_DESC"><code class="Dv">USB_GET_CONFIG_DESC</code></a>
(<var class="Vt">struct usb_config_desc</var>)</dt>
<dd>Return the descriptor for the configuration with the given index. For
convenience, the current configuration can be specified by
<code class="Dv">USB_CURRENT_CONFIG_INDEX</code>.
<div class="Bd Pp Li">
<pre>struct usb_config_desc {
int ucd_config_index;
usb_config_descriptor_t ucd_desc;
};</pre>
</div>
</dd>
<dt id="USB_GET_INTERFACE_DESC"><a class="permalink" href="#USB_GET_INTERFACE_DESC"><code class="Dv">USB_GET_INTERFACE_DESC</code></a>
(<var class="Vt">struct usb_interface_desc</var>)</dt>
<dd>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
<code class="Dv">USB_CURRENT_ALT_INDEX</code>.
<div class="Bd Pp Li">
<pre>struct usb_interface_desc {
int uid_config_index;
int uid_interface_index;
int uid_alt_index;
usb_interface_descriptor_t uid_desc;
};</pre>
</div>
</dd>
<dt id="USB_GET_ENDPOINT_DESC"><a class="permalink" href="#USB_GET_ENDPOINT_DESC"><code class="Dv">USB_GET_ENDPOINT_DESC</code></a>
(<var class="Vt">struct usb_endpoint_desc</var>)</dt>
<dd>Return the endpoint descriptor for the endpoint specified by its
configuration index, interface index, alternative index, and endpoint
index.
<div class="Bd Pp Li">
<pre>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;
};</pre>
</div>
</dd>
<dt id="USB_GET_FULL_DESC"><a class="permalink" href="#USB_GET_FULL_DESC"><code class="Dv">USB_GET_FULL_DESC</code></a>
(<var class="Vt">struct usb_full_desc</var>)</dt>
<dd>Return all the descriptors for the given configuration.
<div class="Bd Pp Li">
<pre>struct usb_full_desc {
int ufd_config_index;
u_int ufd_size;
u_char *ufd_data;
};</pre>
</div>
The <var class="Va">ufd_data</var> field should point to a memory area of
the size given in the <var class="Va">ufd_size</var> field. The proper
size can be determined by first issuing a
<code class="Dv">USB_GET_CONFIG_DESC</code> and inspecting the
<var class="Va">wTotalLength</var> field.</dd>
<dt id="USB_GET_STRING_DESC"><a class="permalink" href="#USB_GET_STRING_DESC"><code class="Dv">USB_GET_STRING_DESC</code></a>
(<var class="Vt">struct usb_string_desc</var>)</dt>
<dd>Get a string descriptor for the given language ID and string index.
<div class="Bd Pp Li">
<pre>struct usb_string_desc {
int usd_string_index;
int usd_language_id;
usb_string_descriptor_t usd_desc;
};</pre>
</div>
</dd>
<dt id="USB_DO_REQUEST"><a class="permalink" href="#USB_DO_REQUEST"><code class="Dv">USB_DO_REQUEST</code></a>
(<var class="Vt">struct usb_ctl_request</var>)</dt>
<dd>Send a USB request to the device on the control endpoint. Any data sent
to/from the device is located at <var class="Va">ucr_data</var>. The size
of the transferred data is determined from the
<var class="Va">ucr_request</var>. The <var class="Va">ucr_addr</var>
field is ignored in this call. The <var class="Va">ucr_flags</var> field
can be used to flag that the request is allowed to be shorter than the
requested size, and <var class="Va">ucr_actlen</var> will contain the
actual size on completion.
<div class="Bd Pp Li">
<pre>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 */
};</pre>
</div>
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.</dd>
<dt id="USB_GET_DEVICEINFO"><a class="permalink" href="#USB_GET_DEVICEINFO"><code class="Dv">USB_GET_DEVICEINFO</code></a>
(<var class="Vt">struct usb_device_info</var>)</dt>
<dd>Get an information summary for the device. This call will not issue any
USB transactions.</dd>
</dl>
<p class="Pp">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 uses the
index, getting and setting typically uses numbers.</p>
<p class="Pp">Example: all endpoints (except the control endpoint) for the
current configuration can be found by iterating the
<var class="Va">interface_index</var> from 0 to
<var class="Va">config_desc->bNumInterface</var>-1 and for each of these,
iterating the <var class="Va">endpoint_index</var> from 0 to
<var class="Va">interface_desc->bNumEndpoints</var>. The
<var class="Va">config_index</var> should be set to
<code class="Dv">USB_CURRENT_CONFIG_INDEX</code> and
<var class="Va">alt_index</var> should be set to
<code class="Dv">USB_CURRENT_ALT_INDEX</code>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYSCTL_VARIABLES"><a class="permalink" href="#SYSCTL_VARIABLES">SYSCTL
VARIABLES</a></h1>
<p class="Pp">The following variables are available as both
<a class="Xr">sysctl(8)</a> variables and <a class="Xr">loader(8)</a>
tunables:</p>
<dl class="Bl-tag">
<dt id="hw.usb.ugen.debug"><var class="Va">hw.usb.ugen.debug</var></dt>
<dd>Debug output level, where 0 is debugging disabled and larger values
increase debug message verbosity. Default is 0.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="FILES"><a class="permalink" href="#FILES">FILES</a></h1>
<dl class="Bl-tag Bl-compact">
<dt><span class="Pa">/dev/usb/B.D.E</span></dt>
<dd>Endpoint <var class="Ar">E</var> of device <var class="Ar">D</var> at bus
<var class="Ar">B</var>.</dd>
<dt><span class="Pa">/dev/ugenB.D</span></dt>
<dd>Control endpoint, 0, of device <var class="Ar">D</var> at bus
<var class="Ar">B</var>.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">usb(4)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">ugen</code> driver appeared in
<span class="Ux">NetBSD 1.4</span>.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">May 14, 2021</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
