1# SPDX-License-Identifier: GPL-2.0 2# 3# USB Gadget support on a system involves 4# (a) a peripheral controller, and 5# (b) the gadget driver using it. 6# 7# NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !! 8# 9# - Host systems (like PCs) need CONFIG_USB (with "A" jacks). 10# - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks). 11# - Some systems have both kinds of controllers. 12# 13# With help from a special transceiver and a "Mini-AB" jack, systems with 14# both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG). 15# 16 17menuconfig USB_GADGET 18 tristate "USB Gadget Support" 19 select USB_COMMON 20 select NLS 21 help 22 USB is a master/slave protocol, organized with one master 23 host (such as a PC) controlling up to 127 peripheral devices. 24 The USB hardware is asymmetric, which makes it easier to set up: 25 you can't connect a "to-the-host" connector to a peripheral. 26 27 Linux can run in the host, or in the peripheral. In both cases 28 you need a low level bus controller driver, and some software 29 talking to it. Peripheral controllers are often discrete silicon, 30 or are integrated with the CPU in a microcontroller. The more 31 familiar host side controllers have names like "EHCI", "OHCI", 32 or "UHCI", and are usually integrated into southbridges on PC 33 motherboards. 34 35 Enable this configuration option if you want to run Linux inside 36 a USB peripheral device. Configure one hardware driver for your 37 peripheral/device side bus controller, and a "gadget driver" for 38 your peripheral protocol. (If you use modular gadget drivers, 39 you may configure more than one.) 40 41 If in doubt, say "N" and don't enable these drivers; most people 42 don't have this kind of hardware (except maybe inside Linux PDAs). 43 44 For more information, see <http://www.linux-usb.org/gadget> and 45 the kernel documentation for this API. 46 47if USB_GADGET 48 49config USB_GADGET_DEBUG 50 bool "Debugging messages (DEVELOPMENT)" 51 depends on DEBUG_KERNEL 52 help 53 Many controller and gadget drivers will print some debugging 54 messages if you use this option to ask for those messages. 55 56 Avoid enabling these messages, even if you're actively 57 debugging such a driver. Many drivers will emit so many 58 messages that the driver timings are affected, which will 59 either create new failure modes or remove the one you're 60 trying to track down. Never enable these messages for a 61 production build. 62 63config USB_GADGET_VERBOSE 64 bool "Verbose debugging Messages (DEVELOPMENT)" 65 depends on USB_GADGET_DEBUG 66 help 67 Many controller and gadget drivers will print verbose debugging 68 messages if you use this option to ask for those messages. 69 70 Avoid enabling these messages, even if you're actively 71 debugging such a driver. Many drivers will emit so many 72 messages that the driver timings are affected, which will 73 either create new failure modes or remove the one you're 74 trying to track down. Never enable these messages for a 75 production build. 76 77config USB_GADGET_DEBUG_FILES 78 bool "Debugging information files (DEVELOPMENT)" 79 depends on PROC_FS 80 help 81 Some of the drivers in the "gadget" framework can expose 82 debugging information in files such as /proc/driver/udc 83 (for a peripheral controller). The information in these 84 files may help when you're troubleshooting or bringing up a 85 driver on a new board. Enable these files by choosing "Y" 86 here. If in doubt, or to conserve kernel memory, say "N". 87 88config USB_GADGET_DEBUG_FS 89 bool "Debugging information files in debugfs (DEVELOPMENT)" 90 depends on DEBUG_FS 91 help 92 Some of the drivers in the "gadget" framework can expose 93 debugging information in files under /sys/kernel/debug/. 94 The information in these files may help when you're 95 troubleshooting or bringing up a driver on a new board. 96 Enable these files by choosing "Y" here. If in doubt, or 97 to conserve kernel memory, say "N". 98 99config USB_GADGET_VBUS_DRAW 100 int "Maximum VBUS Power usage (2-500 mA)" 101 range 2 500 102 default 2 103 help 104 Some devices need to draw power from USB when they are 105 configured, perhaps to operate circuitry or to recharge 106 batteries. This is in addition to any local power supply, 107 such as an AC adapter or batteries. 108 109 Enter the maximum power your device draws through USB, in 110 milliAmperes. The permitted range of values is 2 - 500 mA; 111 0 mA would be legal, but can make some hosts misbehave. 112 113 This value will be used except for system-specific gadget 114 drivers that have more specific information. 115 116config USB_GADGET_STORAGE_NUM_BUFFERS 117 int "Number of storage pipeline buffers" 118 range 2 256 119 default 2 120 help 121 Usually 2 buffers are enough to establish a good buffering 122 pipeline. The number may be increased in order to compensate 123 for a bursty VFS behaviour. For instance there may be CPU wake up 124 latencies that makes the VFS to appear bursty in a system with 125 an CPU on-demand governor. Especially if DMA is doing IO to 126 offload the CPU. In this case the CPU will go into power 127 save often and spin up occasionally to move data within VFS. 128 If selecting USB_GADGET_DEBUG_FILES this value may be set by 129 a module parameter as well. 130 If unsure, say 2. 131 132config U_SERIAL_CONSOLE 133 bool "Serial gadget console support" 134 depends on USB_U_SERIAL 135 help 136 It supports the serial gadget can be used as a console. 137 138source "drivers/usb/gadget/udc/Kconfig" 139 140# 141# USB Gadget Drivers 142# 143 144# composite based drivers 145config USB_LIBCOMPOSITE 146 tristate 147 select CONFIGFS_FS 148 depends on USB_GADGET 149 150config USB_F_ACM 151 tristate 152 153config USB_F_SS_LB 154 tristate 155 156config USB_U_SERIAL 157 tristate 158 159config USB_U_ETHER 160 tristate 161 162config USB_U_AUDIO 163 tristate 164 165config USB_F_SERIAL 166 tristate 167 168config USB_F_OBEX 169 tristate 170 171config USB_F_NCM 172 tristate 173 174config USB_F_ECM 175 tristate 176 177config USB_F_PHONET 178 tristate 179 180config USB_F_EEM 181 tristate 182 183config USB_F_SUBSET 184 tristate 185 186config USB_F_RNDIS 187 tristate 188 189config USB_F_MASS_STORAGE 190 tristate 191 192config USB_F_FS 193 tristate 194 195config USB_F_UAC1 196 tristate 197 198config USB_F_UAC1_LEGACY 199 tristate 200 201config USB_F_UAC2 202 tristate 203 204config USB_F_UVC 205 tristate 206 207config USB_F_MIDI 208 tristate 209 210config USB_F_HID 211 tristate 212 213config USB_F_PRINTER 214 tristate 215 216config USB_F_TCM 217 tristate 218 219# this first set of drivers all depend on bulk-capable hardware. 220 221config USB_CONFIGFS 222 tristate "USB Gadget functions configurable through configfs" 223 select USB_LIBCOMPOSITE 224 help 225 A Linux USB "gadget" can be set up through configfs. 226 If this is the case, the USB functions (which from the host's 227 perspective are seen as interfaces) and configurations are 228 specified simply by creating appropriate directories in configfs. 229 Associating functions with configurations is done by creating 230 appropriate symbolic links. 231 For more information see Documentation/usb/gadget_configfs.txt. 232 233config USB_CONFIGFS_SERIAL 234 bool "Generic serial bulk in/out" 235 depends on USB_CONFIGFS 236 depends on TTY 237 select USB_U_SERIAL 238 select USB_F_SERIAL 239 help 240 The function talks to the Linux-USB generic serial driver. 241 242config USB_CONFIGFS_ACM 243 bool "Abstract Control Model (CDC ACM)" 244 depends on USB_CONFIGFS 245 depends on TTY 246 select USB_U_SERIAL 247 select USB_F_ACM 248 help 249 ACM serial link. This function can be used to interoperate with 250 MS-Windows hosts or with the Linux-USB "cdc-acm" driver. 251 252config USB_CONFIGFS_OBEX 253 bool "Object Exchange Model (CDC OBEX)" 254 depends on USB_CONFIGFS 255 depends on TTY 256 select USB_U_SERIAL 257 select USB_F_OBEX 258 help 259 You will need a user space OBEX server talking to /dev/ttyGS*, 260 since the kernel itself doesn't implement the OBEX protocol. 261 262config USB_CONFIGFS_NCM 263 bool "Network Control Model (CDC NCM)" 264 depends on USB_CONFIGFS 265 depends on NET 266 select USB_U_ETHER 267 select USB_F_NCM 268 help 269 NCM is an advanced protocol for Ethernet encapsulation, allows 270 grouping of several ethernet frames into one USB transfer and 271 different alignment possibilities. 272 273config USB_CONFIGFS_ECM 274 bool "Ethernet Control Model (CDC ECM)" 275 depends on USB_CONFIGFS 276 depends on NET 277 select USB_U_ETHER 278 select USB_F_ECM 279 help 280 The "Communication Device Class" (CDC) Ethernet Control Model. 281 That protocol is often avoided with pure Ethernet adapters, in 282 favor of simpler vendor-specific hardware, but is widely 283 supported by firmware for smart network devices. 284 285config USB_CONFIGFS_ECM_SUBSET 286 bool "Ethernet Control Model (CDC ECM) subset" 287 depends on USB_CONFIGFS 288 depends on NET 289 select USB_U_ETHER 290 select USB_F_SUBSET 291 help 292 On hardware that can't implement the full protocol, 293 a simple CDC subset is used, placing fewer demands on USB. 294 295config USB_CONFIGFS_RNDIS 296 bool "RNDIS" 297 depends on USB_CONFIGFS 298 depends on NET 299 select USB_U_ETHER 300 select USB_F_RNDIS 301 help 302 Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol, 303 and Microsoft provides redistributable binary RNDIS drivers for 304 older versions of Windows. 305 306 To make MS-Windows work with this, use Documentation/usb/linux.inf 307 as the "driver info file". For versions of MS-Windows older than 308 XP, you'll need to download drivers from Microsoft's website; a URL 309 is given in comments found in that info file. 310 311config USB_CONFIGFS_EEM 312 bool "Ethernet Emulation Model (EEM)" 313 depends on USB_CONFIGFS 314 depends on NET 315 select USB_U_ETHER 316 select USB_F_EEM 317 help 318 CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM 319 and therefore can be supported by more hardware. Technically ECM and 320 EEM are designed for different applications. The ECM model extends 321 the network interface to the target (e.g. a USB cable modem), and the 322 EEM model is for mobile devices to communicate with hosts using 323 ethernet over USB. For Linux gadgets, however, the interface with 324 the host is the same (a usbX device), so the differences are minimal. 325 326config USB_CONFIGFS_PHONET 327 bool "Phonet protocol" 328 depends on USB_CONFIGFS 329 depends on NET 330 depends on PHONET 331 select USB_U_ETHER 332 select USB_F_PHONET 333 help 334 The Phonet protocol implementation for USB device. 335 336config USB_CONFIGFS_MASS_STORAGE 337 bool "Mass storage" 338 depends on USB_CONFIGFS 339 depends on BLOCK 340 select USB_F_MASS_STORAGE 341 help 342 The Mass Storage Gadget acts as a USB Mass Storage disk drive. 343 As its storage repository it can use a regular file or a block 344 device (in much the same way as the "loop" device driver), 345 specified as a module parameter or sysfs option. 346 347config USB_CONFIGFS_F_LB_SS 348 bool "Loopback and sourcesink function (for testing)" 349 depends on USB_CONFIGFS 350 select USB_F_SS_LB 351 help 352 Loopback function loops back a configurable number of transfers. 353 Sourcesink function either sinks and sources bulk data. 354 It also implements control requests, for "chapter 9" conformance. 355 Make this be the first driver you try using on top of any new 356 USB peripheral controller driver. Then you can use host-side 357 test software, like the "usbtest" driver, to put your hardware 358 and its driver through a basic set of functional tests. 359 360config USB_CONFIGFS_F_FS 361 bool "Function filesystem (FunctionFS)" 362 depends on USB_CONFIGFS 363 select USB_F_FS 364 help 365 The Function Filesystem (FunctionFS) lets one create USB 366 composite functions in user space in the same way GadgetFS 367 lets one create USB gadgets in user space. This allows creation 368 of composite gadgets such that some of the functions are 369 implemented in kernel space (for instance Ethernet, serial or 370 mass storage) and other are implemented in user space. 371 372config USB_CONFIGFS_F_UAC1 373 bool "Audio Class 1.0" 374 depends on USB_CONFIGFS 375 depends on SND 376 select USB_LIBCOMPOSITE 377 select SND_PCM 378 select USB_U_AUDIO 379 select USB_F_UAC1 380 help 381 This Audio function implements 1 AudioControl interface, 382 1 AudioStreaming Interface each for USB-OUT and USB-IN. 383 This driver doesn't expect any real Audio codec to be present 384 on the device - the audio streams are simply sinked to and 385 sourced from a virtual ALSA sound card created. The user-space 386 application may choose to do whatever it wants with the data 387 received from the USB Host and choose to provide whatever it 388 wants as audio data to the USB Host. 389 390config USB_CONFIGFS_F_UAC1_LEGACY 391 bool "Audio Class 1.0 (legacy implementation)" 392 depends on USB_CONFIGFS 393 depends on SND 394 select USB_LIBCOMPOSITE 395 select SND_PCM 396 select USB_F_UAC1_LEGACY 397 help 398 This Audio function implements 1 AudioControl interface, 399 1 AudioStreaming Interface each for USB-OUT and USB-IN. 400 This is a legacy driver and requires a real Audio codec 401 to be present on the device. 402 403config USB_CONFIGFS_F_UAC2 404 bool "Audio Class 2.0" 405 depends on USB_CONFIGFS 406 depends on SND 407 select USB_LIBCOMPOSITE 408 select SND_PCM 409 select USB_U_AUDIO 410 select USB_F_UAC2 411 help 412 This Audio function is compatible with USB Audio Class 413 specification 2.0. It implements 1 AudioControl interface, 414 1 AudioStreaming Interface each for USB-OUT and USB-IN. 415 This driver doesn't expect any real Audio codec to be present 416 on the device - the audio streams are simply sinked to and 417 sourced from a virtual ALSA sound card created. The user-space 418 application may choose to do whatever it wants with the data 419 received from the USB Host and choose to provide whatever it 420 wants as audio data to the USB Host. 421 422config USB_CONFIGFS_F_MIDI 423 bool "MIDI function" 424 depends on USB_CONFIGFS 425 depends on SND 426 select USB_LIBCOMPOSITE 427 select SND_RAWMIDI 428 select USB_F_MIDI 429 help 430 The MIDI Function acts as a USB Audio device, with one MIDI 431 input and one MIDI output. These MIDI jacks appear as 432 a sound "card" in the ALSA sound system. Other MIDI 433 connections can then be made on the gadget system, using 434 ALSA's aconnect utility etc. 435 436config USB_CONFIGFS_F_HID 437 bool "HID function" 438 depends on USB_CONFIGFS 439 select USB_F_HID 440 help 441 The HID function driver provides generic emulation of USB 442 Human Interface Devices (HID). 443 444 For more information, see Documentation/usb/gadget_hid.txt. 445 446config USB_CONFIGFS_F_UVC 447 bool "USB Webcam function" 448 depends on USB_CONFIGFS 449 depends on VIDEO_V4L2 450 depends on VIDEO_DEV 451 select VIDEOBUF2_VMALLOC 452 select USB_F_UVC 453 help 454 The Webcam function acts as a composite USB Audio and Video Class 455 device. It provides a userspace API to process UVC control requests 456 and stream video data to the host. 457 458config USB_CONFIGFS_F_PRINTER 459 bool "Printer function" 460 select USB_F_PRINTER 461 depends on USB_CONFIGFS 462 help 463 The Printer function channels data between the USB host and a 464 userspace program driving the print engine. The user space 465 program reads and writes the device file /dev/g_printer<X> to 466 receive or send printer data. It can use ioctl calls to 467 the device file to get or set printer status. 468 469 For more information, see Documentation/usb/gadget_printer.txt 470 which includes sample code for accessing the device file. 471 472config USB_CONFIGFS_F_TCM 473 bool "USB Gadget Target Fabric" 474 depends on TARGET_CORE 475 depends on USB_CONFIGFS 476 select USB_LIBCOMPOSITE 477 select USB_F_TCM 478 help 479 This fabric is a USB gadget component. Two USB protocols are 480 supported that is BBB or BOT (Bulk Only Transport) and UAS 481 (USB Attached SCSI). BOT is advertised on alternative 482 interface 0 (primary) and UAS is on alternative interface 1. 483 Both protocols can work on USB2.0 and USB3.0. 484 UAS utilizes the USB 3.0 feature called streams support. 485 486choice 487 tristate "USB Gadget precomposed configurations" 488 default USB_ETH 489 optional 490 help 491 A Linux "Gadget Driver" talks to the USB Peripheral Controller 492 driver through the abstract "gadget" API. Some other operating 493 systems call these "client" drivers, of which "class drivers" 494 are a subset (implementing a USB device class specification). 495 A gadget driver implements one or more USB functions using 496 the peripheral hardware. 497 498 Gadget drivers are hardware-neutral, or "platform independent", 499 except that they sometimes must understand quirks or limitations 500 of the particular controllers they work with. For example, when 501 a controller doesn't support alternate configurations or provide 502 enough of the right types of endpoints, the gadget driver might 503 not be able work with that controller, or might need to implement 504 a less common variant of a device class protocol. 505 506 The available choices each represent a single precomposed USB 507 gadget configuration. In the device model, each option contains 508 both the device instantiation as a child for a USB gadget 509 controller, and the relevant drivers for each function declared 510 by the device. 511 512source "drivers/usb/gadget/legacy/Kconfig" 513 514endchoice 515 516endif # USB_GADGET 517