tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 host/device protocol, organized with one host (such as a
23 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 select DMA_SHARED_BUFFER
194 tristate
195
196config USB_F_UAC1
197 tristate
198
199config USB_F_UAC1_LEGACY
200 tristate
201
202config USB_F_UAC2
203 tristate
204
205config USB_F_UVC
206 tristate
207 select UVC_COMMON
208
209config USB_F_MIDI
210 tristate
211
212config USB_F_MIDI2
213 tristate
214 select SND_UMP
215 select SND_UMP_LEGACY_RAWMIDI
216
217config USB_F_HID
218 tristate
219
220config USB_F_PRINTER
221 tristate
222
223config USB_F_TCM
224 tristate
225
226# this first set of drivers all depend on bulk-capable hardware.
227
228config USB_CONFIGFS
229 tristate "USB Gadget functions configurable through configfs"
230 select USB_LIBCOMPOSITE
231 help
232 A Linux USB "gadget" can be set up through configfs.
233 If this is the case, the USB functions (which from the host's
234 perspective are seen as interfaces) and configurations are
235 specified simply by creating appropriate directories in configfs.
236 Associating functions with configurations is done by creating
237 appropriate symbolic links.
238 For more information see Documentation/usb/gadget_configfs.rst.
239
240config USB_CONFIGFS_SERIAL
241 bool "Generic serial bulk in/out"
242 depends on USB_CONFIGFS
243 depends on TTY
244 select USB_U_SERIAL
245 select USB_F_SERIAL
246 help
247 The function talks to the Linux-USB generic serial driver.
248
249config USB_CONFIGFS_ACM
250 bool "Abstract Control Model (CDC ACM)"
251 depends on USB_CONFIGFS
252 depends on TTY
253 select USB_U_SERIAL
254 select USB_F_ACM
255 help
256 ACM serial link. This function can be used to interoperate with
257 MS-Windows hosts or with the Linux-USB "cdc-acm" driver.
258
259config USB_CONFIGFS_OBEX
260 bool "Object Exchange Model (CDC OBEX)"
261 depends on USB_CONFIGFS
262 depends on TTY
263 select USB_U_SERIAL
264 select USB_F_OBEX
265 help
266 You will need a user space OBEX server talking to /dev/ttyGS*,
267 since the kernel itself doesn't implement the OBEX protocol.
268
269config USB_CONFIGFS_NCM
270 bool "Network Control Model (CDC NCM)"
271 depends on USB_CONFIGFS
272 depends on NET
273 select USB_U_ETHER
274 select USB_F_NCM
275 select CRC32
276 help
277 NCM is an advanced protocol for Ethernet encapsulation, allows
278 grouping of several ethernet frames into one USB transfer and
279 different alignment possibilities.
280
281config USB_CONFIGFS_ECM
282 bool "Ethernet Control Model (CDC ECM)"
283 depends on USB_CONFIGFS
284 depends on NET
285 select USB_U_ETHER
286 select USB_F_ECM
287 help
288 The "Communication Device Class" (CDC) Ethernet Control Model.
289 That protocol is often avoided with pure Ethernet adapters, in
290 favor of simpler vendor-specific hardware, but is widely
291 supported by firmware for smart network devices.
292
293config USB_CONFIGFS_ECM_SUBSET
294 bool "Ethernet Control Model (CDC ECM) subset"
295 depends on USB_CONFIGFS
296 depends on NET
297 select USB_U_ETHER
298 select USB_F_SUBSET
299 help
300 On hardware that can't implement the full protocol,
301 a simple CDC subset is used, placing fewer demands on USB.
302
303config USB_CONFIGFS_RNDIS
304 bool "RNDIS"
305 depends on USB_CONFIGFS
306 depends on NET
307 select USB_U_ETHER
308 select USB_F_RNDIS
309 help
310 Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
311 and Microsoft provides redistributable binary RNDIS drivers for
312 older versions of Windows.
313
314 To make MS-Windows work with this, use Documentation/usb/linux.inf
315 as the "driver info file". For versions of MS-Windows older than
316 XP, you'll need to download drivers from Microsoft's website; a URL
317 is given in comments found in that info file.
318
319config USB_CONFIGFS_EEM
320 bool "Ethernet Emulation Model (EEM)"
321 depends on USB_CONFIGFS
322 depends on NET
323 select USB_U_ETHER
324 select USB_F_EEM
325 select CRC32
326 help
327 CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
328 and therefore can be supported by more hardware. Technically ECM and
329 EEM are designed for different applications. The ECM model extends
330 the network interface to the target (e.g. a USB cable modem), and the
331 EEM model is for mobile devices to communicate with hosts using
332 ethernet over USB. For Linux gadgets, however, the interface with
333 the host is the same (a usbX device), so the differences are minimal.
334
335config USB_CONFIGFS_PHONET
336 bool "Phonet protocol"
337 depends on USB_CONFIGFS
338 depends on NET
339 depends on PHONET
340 select USB_U_ETHER
341 select USB_F_PHONET
342 help
343 The Phonet protocol implementation for USB device.
344
345config USB_CONFIGFS_MASS_STORAGE
346 bool "Mass storage"
347 depends on USB_CONFIGFS
348 depends on BLOCK
349 select USB_F_MASS_STORAGE
350 help
351 The Mass Storage Gadget acts as a USB Mass Storage disk drive.
352 As its storage repository it can use a regular file or a block
353 device (in much the same way as the "loop" device driver),
354 specified as a module parameter or sysfs option.
355
356config USB_CONFIGFS_F_LB_SS
357 bool "Loopback and sourcesink function (for testing)"
358 depends on USB_CONFIGFS
359 select USB_F_SS_LB
360 help
361 Loopback function loops back a configurable number of transfers.
362 Sourcesink function either sinks and sources bulk data.
363 It also implements control requests, for "chapter 9" conformance.
364 Make this be the first driver you try using on top of any new
365 USB peripheral controller driver. Then you can use host-side
366 test software, like the "usbtest" driver, to put your hardware
367 and its driver through a basic set of functional tests.
368
369config USB_CONFIGFS_F_FS
370 bool "Function filesystem (FunctionFS)"
371 depends on USB_CONFIGFS
372 select USB_F_FS
373 help
374 The Function Filesystem (FunctionFS) lets one create USB
375 composite functions in user space in the same way GadgetFS
376 lets one create USB gadgets in user space. This allows creation
377 of composite gadgets such that some of the functions are
378 implemented in kernel space (for instance Ethernet, serial or
379 mass storage) and other are implemented in user space.
380
381config USB_CONFIGFS_F_UAC1
382 bool "Audio Class 1.0"
383 depends on USB_CONFIGFS
384 depends on SND
385 select USB_LIBCOMPOSITE
386 select SND_PCM
387 select USB_U_AUDIO
388 select USB_F_UAC1
389 help
390 This Audio function implements 1 AudioControl interface,
391 1 AudioStreaming Interface each for USB-OUT and USB-IN.
392 This driver doesn't expect any real Audio codec to be present
393 on the device - the audio streams are simply sinked to and
394 sourced from a virtual ALSA sound card created. The user-space
395 application may choose to do whatever it wants with the data
396 received from the USB Host and choose to provide whatever it
397 wants as audio data to the USB Host.
398
399config USB_CONFIGFS_F_UAC1_LEGACY
400 bool "Audio Class 1.0 (legacy implementation)"
401 depends on USB_CONFIGFS
402 depends on SND
403 select USB_LIBCOMPOSITE
404 select SND_PCM
405 select USB_F_UAC1_LEGACY
406 help
407 This Audio function implements 1 AudioControl interface,
408 1 AudioStreaming Interface each for USB-OUT and USB-IN.
409 This is a legacy driver and requires a real Audio codec
410 to be present on the device.
411
412config USB_CONFIGFS_F_UAC2
413 bool "Audio Class 2.0"
414 depends on USB_CONFIGFS
415 depends on SND
416 select USB_LIBCOMPOSITE
417 select SND_PCM
418 select USB_U_AUDIO
419 select USB_F_UAC2
420 help
421 This Audio function is compatible with USB Audio Class
422 specification 2.0. It implements 1 AudioControl interface,
423 1 AudioStreaming Interface each for USB-OUT and USB-IN.
424 This driver doesn't expect any real Audio codec to be present
425 on the device - the audio streams are simply sinked to and
426 sourced from a virtual ALSA sound card created. The user-space
427 application may choose to do whatever it wants with the data
428 received from the USB Host and choose to provide whatever it
429 wants as audio data to the USB Host.
430
431config USB_CONFIGFS_F_MIDI
432 bool "MIDI function"
433 depends on USB_CONFIGFS
434 depends on SND
435 select USB_LIBCOMPOSITE
436 select SND_RAWMIDI
437 select USB_F_MIDI
438 help
439 The MIDI Function acts as a USB Audio device, with one MIDI
440 input and one MIDI output. These MIDI jacks appear as
441 a sound "card" in the ALSA sound system. Other MIDI
442 connections can then be made on the gadget system, using
443 ALSA's aconnect utility etc.
444
445config USB_CONFIGFS_F_MIDI2
446 bool "MIDI 2.0 function"
447 depends on USB_CONFIGFS
448 depends on SND
449 select USB_LIBCOMPOSITE
450 select USB_F_MIDI2
451 help
452 The MIDI 2.0 function driver provides the generic emulated
453 USB MIDI 2.0 interface, looped back to ALSA UMP rawmidi
454 device on the gadget host. It supports UMP 1.1 spec and
455 responds UMP Stream messages for UMP Endpoint and Function
456 Block information / configuration.
457
458config USB_CONFIGFS_F_HID
459 bool "HID function"
460 depends on USB_CONFIGFS
461 select USB_F_HID
462 help
463 The HID function driver provides generic emulation of USB
464 Human Interface Devices (HID).
465
466 For more information, see Documentation/usb/gadget_hid.rst.
467
468config USB_CONFIGFS_F_UVC
469 bool "USB Webcam function"
470 depends on USB_CONFIGFS
471 depends on VIDEO_DEV
472 depends on VIDEO_DEV
473 select VIDEOBUF2_DMA_SG
474 select VIDEOBUF2_VMALLOC
475 select USB_F_UVC
476 help
477 The Webcam function acts as a composite USB Audio and Video Class
478 device. It provides a userspace API to process UVC control requests
479 and stream video data to the host.
480
481config USB_CONFIGFS_F_PRINTER
482 bool "Printer function"
483 select USB_F_PRINTER
484 depends on USB_CONFIGFS
485 help
486 The Printer function channels data between the USB host and a
487 userspace program driving the print engine. The user space
488 program reads and writes the device file /dev/g_printer<X> to
489 receive or send printer data. It can use ioctl calls to
490 the device file to get or set printer status.
491
492 For more information, see Documentation/usb/gadget_printer.rst
493 which includes sample code for accessing the device file.
494
495config USB_CONFIGFS_F_TCM
496 bool "USB Gadget Target Fabric"
497 depends on TARGET_CORE
498 depends on USB_CONFIGFS
499 select USB_LIBCOMPOSITE
500 select USB_F_TCM
501 help
502 This fabric is a USB gadget component. Two USB protocols are
503 supported that is BBB or BOT (Bulk Only Transport) and UAS
504 (USB Attached SCSI). BOT is advertised on alternative
505 interface 0 (primary) and UAS is on alternative interface 1.
506 Both protocols can work on USB2.0 and USB3.0.
507 UAS utilizes the USB 3.0 feature called streams support.
508
509source "drivers/usb/gadget/legacy/Kconfig"
510
511endif # USB_GADGET