1.\" $NetBSD: ugen.4,v 1.13 2001/09/11 22:52:54 wiz Exp $ 2.\" 3.\" Copyright (c) 1999 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Lennart Augustsson. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd May 14, 2021 31.Dt UGEN 4 32.Os 33.Sh NAME 34.Nm ugen 35.Nd USB generic device support 36.Sh SYNOPSIS 37.Nm 38is integrated into the 39.Xr usb 4 40kernel module. 41.Sh DESCRIPTION 42The 43.Nm 44driver provides support for all USB devices that do not have 45a special driver. 46It supports access to all parts of the device, 47but not in a way that is as convenient as a special purpose driver. 48.Pp 49There can be up to 127 USB devices connected to a USB bus. 50Each USB device can have up to 16 endpoints. 51Each of these endpoints 52will communicate in one of four different modes: control, isochronous, 53bulk, or interrupt. 54Each of the endpoints will have a different 55device node. 56The four least significant bits in the minor device 57number determine which endpoint the device accesses, and the rest 58of the bits determine which USB device. 59.Pp 60If an endpoint address is used both for input and output, the device 61can be opened for both read or write. 62.Pp 63To find out which endpoints exist, there are a series of 64.Xr ioctl 2 65operations on the control endpoint that return the USB descriptors 66of the device, configurations, interfaces, and endpoints. 67.Pp 68The control transfer mode can only happen on the control endpoint 69which is always endpoint 0. 70The control endpoint accepts a request 71and may respond with an answer to such a request. 72Control requests 73are issued by 74.Xr ioctl 2 75calls. 76.\" .Pp 77.\" The isochronous transfer mode can be in or out depending on the 78.\" endpoint. 79.\" To perform I/O on an isochronous endpoint 80.\" .Xr read 2 81.\" and 82.\" .Xr write 2 83.\" should be used. 84.\" Before any I/O operations can take place the transfer rate in 85.\" bytes/second has to be set. 86.\" This is done with 87.\" .Xr ioctl 2 88.\" .Dv USB_SET_ISO_RATE . 89.\" Performing this call sets up a buffer corresponding to 90.\" about 1 second of data. 91.Pp 92The bulk transfer mode can be in or out depending on the 93endpoint. 94To perform I/O on a bulk endpoint 95.Xr read 2 96and 97.Xr write 2 98should be used. 99All I/O operations on a bulk endpoint are unbuffered. 100.Pp 101The interrupt transfer mode can be in or out depending on the 102endpoint. 103To perform I/O on an interrupt endpoint 104.Xr read 2 105and 106.Xr write 2 107should be used. 108A moderate amount of buffering is done 109by the driver. 110.Pp 111All endpoints handle the following 112.Xr ioctl 2 113calls: 114.Bl -tag -width indent 115.It Dv USB_SET_SHORT_XFER Pq Vt int 116Allow short read transfer. 117Normally a transfer from the device 118which is shorter than the request specified is reported as an 119error. 120.It Dv USB_SET_TIMEOUT Pq Vt int 121Set the timeout on the device operations 122The time is specified in milliseconds. 123The value 0 is used to indicate that there is 124no timeout. 125.El 126.Pp 127The control endpoint (endpoint 0) handles the following 128.Xr ioctl 2 129calls: 130.Bl -tag -width indent 131.It Dv USB_GET_CONFIG Pq Vt int 132Get the device configuration number. 133.It Dv USB_SET_CONFIG Pq Vt int 134Set the device into the given configuration number. 135.Pp 136This operation can only be performed when the control endpoint 137is the sole open endpoint. 138.It Dv USB_GET_ALTINTERFACE Pq Vt "struct usb_alt_interface" 139Get the alternative setting number for the interface with the given 140index. 141The 142.Va uai_config_index 143is ignored in this call. 144.Bd -literal 145struct usb_alt_interface { 146 int uai_config_index; 147 int uai_interface_index; 148 int uai_alt_no; 149}; 150.Ed 151.It Dv USB_SET_ALTINTERFACE Pq Vt "struct usb_alt_interface" 152Set the alternative setting to the given number in the interface with the 153given index. 154The 155.Va uai_config_index 156is ignored in this call. 157.Pp 158This operation can only be performed when no endpoints for the interface 159are open. 160.It Dv USB_GET_NO_ALT Pq Vt "struct usb_alt_interface" 161Return the number of different alternate settings in the 162.Va uai_alt_no 163field. 164.It Dv USB_GET_DEVICE_DESC Pq Vt usb_device_descriptor_t 165Return the device descriptor. 166.It Dv USB_GET_CONFIG_DESC Pq Vt "struct usb_config_desc" 167Return the descriptor for the configuration with the given index. 168For convenience, the current configuration can be specified by 169.Dv USB_CURRENT_CONFIG_INDEX . 170.Bd -literal 171struct usb_config_desc { 172 int ucd_config_index; 173 usb_config_descriptor_t ucd_desc; 174}; 175.Ed 176.It Dv USB_GET_INTERFACE_DESC Pq Vt "struct usb_interface_desc" 177Return the interface descriptor for an interface specified by its 178configuration index, interface index, and alternative index. 179For convenience, the current alternative can be specified by 180.Dv USB_CURRENT_ALT_INDEX . 181.Bd -literal 182struct usb_interface_desc { 183 int uid_config_index; 184 int uid_interface_index; 185 int uid_alt_index; 186 usb_interface_descriptor_t uid_desc; 187}; 188.Ed 189.It Dv USB_GET_ENDPOINT_DESC Pq Vt "struct usb_endpoint_desc" 190Return the endpoint descriptor for the endpoint specified by its 191configuration index, interface index, alternative index, and 192endpoint index. 193.Bd -literal 194struct usb_endpoint_desc { 195 int ued_config_index; 196 int ued_interface_index; 197 int ued_alt_index; 198 int ued_endpoint_index; 199 usb_endpoint_descriptor_t ued_desc; 200}; 201.Ed 202.It Dv USB_GET_FULL_DESC Pq Vt "struct usb_full_desc" 203Return all the descriptors for the given configuration. 204.Bd -literal 205struct usb_full_desc { 206 int ufd_config_index; 207 u_int ufd_size; 208 u_char *ufd_data; 209}; 210.Ed 211The 212.Va ufd_data 213field should point to a memory area of the size given in the 214.Va ufd_size 215field. 216The proper size can be determined by first issuing a 217.Dv USB_GET_CONFIG_DESC 218and inspecting the 219.Va wTotalLength 220field. 221.It Dv USB_GET_STRING_DESC Pq Vt "struct usb_string_desc" 222Get a string descriptor for the given language ID and 223string index. 224.Bd -literal 225struct usb_string_desc { 226 int usd_string_index; 227 int usd_language_id; 228 usb_string_descriptor_t usd_desc; 229}; 230.Ed 231.It Dv USB_DO_REQUEST Pq Vt "struct usb_ctl_request" 232Send a USB request to the device on the control endpoint. 233Any data sent to/from the device is located at 234.Va ucr_data . 235The size of the transferred data is determined from the 236.Va ucr_request . 237The 238.Va ucr_addr 239field is ignored in this call. 240The 241.Va ucr_flags 242field can be used to flag that the request is allowed to 243be shorter than the requested size, and 244.Va ucr_actlen 245will contain the actual size on completion. 246.Bd -literal 247struct usb_ctl_request { 248 int ucr_addr; 249 usb_device_request_t ucr_request; 250 void *ucr_data; 251 int ucr_flags; 252#define USBD_SHORT_XFER_OK 0x04 /* allow short reads */ 253 int ucr_actlen; /* actual length transferred */ 254}; 255.Ed 256This is a dangerous operation in that it can perform arbitrary operations 257on the device. 258Some of the most dangerous (e.g., changing the device 259address) are not allowed. 260.It Dv USB_GET_DEVICEINFO Pq Vt "struct usb_device_info" 261Get an information summary for the device. 262This call will not issue any USB transactions. 263.El 264.Pp 265Note that there are two different ways of addressing configurations, 266interfaces, alternatives, and endpoints: by index or by number. 267The index is the ordinal number (starting from 0) of the descriptor 268as presented by the device. 269The number is the respective number of 270the entity as found in its descriptor. 271Enumeration of descriptors 272uses the index, getting and setting typically uses numbers. 273.Pp 274Example: 275all endpoints (except the control endpoint) for the current configuration 276can be found by iterating the 277.Va interface_index 278from 0 to 279.Va config_desc->bNumInterface Ns \-1 280and for each of these, iterating the 281.Va endpoint_index 282from 0 to 283.Va interface_desc->bNumEndpoints . 284The 285.Va config_index 286should be set to 287.Dv USB_CURRENT_CONFIG_INDEX 288and 289.Va alt_index 290should be set to 291.Dv USB_CURRENT_ALT_INDEX . 292.Sh SYSCTL VARIABLES 293The following variables are available as both 294.Xr sysctl 8 295variables and 296.Xr loader 8 297tunables: 298.Bl -tag -width indent 299.It Va hw.usb.ugen.debug 300Debug output level, where 0 is debugging disabled and larger values increase 301debug message verbosity. 302Default is 0. 303.El 304.Sh FILES 305.Bl -tag -width "/dev/usb/B.D.E" -compact 306.It Pa /dev/usb/B.D.E 307Endpoint 308.Ar E 309of device 310.Ar D 311at bus 312.Ar B . 313.It Pa /dev/ugenB.D 314Control endpoint, 0, of device 315.Ar D 316at bus 317.Ar B . 318.El 319.Sh SEE ALSO 320.Xr usb 4 321.Sh HISTORY 322The 323.Nm 324driver 325appeared in 326.Nx 1.4 . 327