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.\" $FreeBSD$ 31.\" 32.Dd May 14, 2021 33.Dt UGEN 4 34.Os 35.Sh NAME 36.Nm ugen 37.Nd USB generic device support 38.Sh SYNOPSIS 39.Nm 40is integrated into the 41.Xr usb 4 42kernel module. 43.Sh DESCRIPTION 44The 45.Nm 46driver provides support for all USB devices that do not have 47a special driver. 48It supports access to all parts of the device, 49but not in a way that is as convenient as a special purpose driver. 50.Pp 51There can be up to 127 USB devices connected to a USB bus. 52Each USB device can have up to 16 endpoints. 53Each of these endpoints 54will communicate in one of four different modes: control, isochronous, 55bulk, or interrupt. 56Each of the endpoints will have a different 57device node. 58The four least significant bits in the minor device 59number determine which endpoint the device accesses, and the rest 60of the bits determine which USB device. 61.Pp 62If an endpoint address is used both for input and output, the device 63can be opened for both read or write. 64.Pp 65To find out which endpoints exist, there are a series of 66.Xr ioctl 2 67operations on the control endpoint that return the USB descriptors 68of the device, configurations, interfaces, and endpoints. 69.Pp 70The control transfer mode can only happen on the control endpoint 71which is always endpoint 0. 72The control endpoint accepts a request 73and may respond with an answer to such a request. 74Control requests 75are issued by 76.Xr ioctl 2 77calls. 78.\" .Pp 79.\" The isochronous transfer mode can be in or out depending on the 80.\" endpoint. 81.\" To perform I/O on an isochronous endpoint 82.\" .Xr read 2 83.\" and 84.\" .Xr write 2 85.\" should be used. 86.\" Before any I/O operations can take place the transfer rate in 87.\" bytes/second has to be set. 88.\" This is done with 89.\" .Xr ioctl 2 90.\" .Dv USB_SET_ISO_RATE . 91.\" Performing this call sets up a buffer corresponding to 92.\" about 1 second of data. 93.Pp 94The bulk transfer mode can be in or out depending on the 95endpoint. 96To perform I/O on a bulk endpoint 97.Xr read 2 98and 99.Xr write 2 100should be used. 101All I/O operations on a bulk endpoint are unbuffered. 102.Pp 103The interrupt transfer mode can be in or out depending on the 104endpoint. 105To perform I/O on an interrupt endpoint 106.Xr read 2 107and 108.Xr write 2 109should be used. 110A moderate amount of buffering is done 111by the driver. 112.Pp 113All endpoints handle the following 114.Xr ioctl 2 115calls: 116.Bl -tag -width indent 117.It Dv USB_SET_SHORT_XFER Pq Vt int 118Allow short read transfer. 119Normally a transfer from the device 120which is shorter than the request specified is reported as an 121error. 122.It Dv USB_SET_TIMEOUT Pq Vt int 123Set the timeout on the device operations 124The time is specified in milliseconds. 125The value 0 is used to indicate that there is 126no timeout. 127.El 128.Pp 129The control endpoint (endpoint 0) handles the following 130.Xr ioctl 2 131calls: 132.Bl -tag -width indent 133.It Dv USB_GET_CONFIG Pq Vt int 134Get the device configuration number. 135.It Dv USB_SET_CONFIG Pq Vt int 136Set the device into the given configuration number. 137.Pp 138This operation can only be performed when the control endpoint 139is the sole open endpoint. 140.It Dv USB_GET_ALTINTERFACE Pq Vt "struct usb_alt_interface" 141Get the alternative setting number for the interface with the given 142index. 143The 144.Va uai_config_index 145is ignored in this call. 146.Bd -literal 147struct usb_alt_interface { 148 int uai_config_index; 149 int uai_interface_index; 150 int uai_alt_no; 151}; 152.Ed 153.It Dv USB_SET_ALTINTERFACE Pq Vt "struct usb_alt_interface" 154Set the alternative setting to the given number in the interface with the 155given index. 156The 157.Va uai_config_index 158is ignored in this call. 159.Pp 160This operation can only be performed when no endpoints for the interface 161are open. 162.It Dv USB_GET_NO_ALT Pq Vt "struct usb_alt_interface" 163Return the number of different alternate settings in the 164.Va uai_alt_no 165field. 166.It Dv USB_GET_DEVICE_DESC Pq Vt usb_device_descriptor_t 167Return the device descriptor. 168.It Dv USB_GET_CONFIG_DESC Pq Vt "struct usb_config_desc" 169Return the descriptor for the configuration with the given index. 170For convenience, the current configuration can be specified by 171.Dv USB_CURRENT_CONFIG_INDEX . 172.Bd -literal 173struct usb_config_desc { 174 int ucd_config_index; 175 usb_config_descriptor_t ucd_desc; 176}; 177.Ed 178.It Dv USB_GET_INTERFACE_DESC Pq Vt "struct usb_interface_desc" 179Return the interface descriptor for an interface specified by its 180configuration index, interface index, and alternative index. 181For convenience, the current alternative can be specified by 182.Dv USB_CURRENT_ALT_INDEX . 183.Bd -literal 184struct usb_interface_desc { 185 int uid_config_index; 186 int uid_interface_index; 187 int uid_alt_index; 188 usb_interface_descriptor_t uid_desc; 189}; 190.Ed 191.It Dv USB_GET_ENDPOINT_DESC Pq Vt "struct usb_endpoint_desc" 192Return the endpoint descriptor for the endpoint specified by its 193configuration index, interface index, alternative index, and 194endpoint index. 195.Bd -literal 196struct usb_endpoint_desc { 197 int ued_config_index; 198 int ued_interface_index; 199 int ued_alt_index; 200 int ued_endpoint_index; 201 usb_endpoint_descriptor_t ued_desc; 202}; 203.Ed 204.It Dv USB_GET_FULL_DESC Pq Vt "struct usb_full_desc" 205Return all the descriptors for the given configuration. 206.Bd -literal 207struct usb_full_desc { 208 int ufd_config_index; 209 u_int ufd_size; 210 u_char *ufd_data; 211}; 212.Ed 213The 214.Va ufd_data 215field should point to a memory area of the size given in the 216.Va ufd_size 217field. 218The proper size can be determined by first issuing a 219.Dv USB_GET_CONFIG_DESC 220and inspecting the 221.Va wTotalLength 222field. 223.It Dv USB_GET_STRING_DESC Pq Vt "struct usb_string_desc" 224Get a string descriptor for the given language ID and 225string index. 226.Bd -literal 227struct usb_string_desc { 228 int usd_string_index; 229 int usd_language_id; 230 usb_string_descriptor_t usd_desc; 231}; 232.Ed 233.It Dv USB_DO_REQUEST Pq Vt "struct usb_ctl_request" 234Send a USB request to the device on the control endpoint. 235Any data sent to/from the device is located at 236.Va ucr_data . 237The size of the transferred data is determined from the 238.Va ucr_request . 239The 240.Va ucr_addr 241field is ignored in this call. 242The 243.Va ucr_flags 244field can be used to flag that the request is allowed to 245be shorter than the requested size, and 246.Va ucr_actlen 247will contain the actual size on completion. 248.Bd -literal 249struct usb_ctl_request { 250 int ucr_addr; 251 usb_device_request_t ucr_request; 252 void *ucr_data; 253 int ucr_flags; 254#define USBD_SHORT_XFER_OK 0x04 /* allow short reads */ 255 int ucr_actlen; /* actual length transferred */ 256}; 257.Ed 258This is a dangerous operation in that it can perform arbitrary operations 259on the device. 260Some of the most dangerous (e.g., changing the device 261address) are not allowed. 262.It Dv USB_GET_DEVICEINFO Pq Vt "struct usb_device_info" 263Get an information summary for the device. 264This call will not issue any USB transactions. 265.El 266.Pp 267Note that there are two different ways of addressing configurations, 268interfaces, alternatives, and endpoints: by index or by number. 269The index is the ordinal number (starting from 0) of the descriptor 270as presented by the device. 271The number is the respective number of 272the entity as found in its descriptor. 273Enumeration of descriptors 274uses the index, getting and setting typically uses numbers. 275.Pp 276Example: 277all endpoints (except the control endpoint) for the current configuration 278can be found by iterating the 279.Va interface_index 280from 0 to 281.Va config_desc->bNumInterface Ns \-1 282and for each of these, iterating the 283.Va endpoint_index 284from 0 to 285.Va interface_desc->bNumEndpoints . 286The 287.Va config_index 288should be set to 289.Dv USB_CURRENT_CONFIG_INDEX 290and 291.Va alt_index 292should be set to 293.Dv USB_CURRENT_ALT_INDEX . 294.Sh SYSCTL VARIABLES 295The following variables are available as both 296.Xr sysctl 8 297variables and 298.Xr loader 8 299tunables: 300.Bl -tag -width indent 301.It Va hw.usb.ugen.debug 302Debug output level, where 0 is debugging disabled and larger values increase 303debug message verbosity. 304Default is 0. 305.El 306.Sh FILES 307.Bl -tag -width "/dev/usb/B.D.E" -compact 308.It Pa /dev/usb/B.D.E 309Endpoint 310.Ar E 311of device 312.Ar D 313at bus 314.Ar B . 315.It Pa /dev/ugenB.D 316Control endpoint, 0, of device 317.Ar D 318at bus 319.Ar B . 320.El 321.Sh SEE ALSO 322.Xr usb 4 323.Sh HISTORY 324The 325.Nm 326driver 327appeared in 328.Nx 1.4 . 329