# SPDX-License-Identifier: GPL-2.0
#
# USB Gadget support on a system involves
# (a) a peripheral controller, and
# (b) the gadget driver using it.
#
# NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !!
#
# - Host systems (like PCs) need CONFIG_USB (with "A" jacks).
# - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks).
# - Some systems have both kinds of controllers.
#
# With help from a special transceiver and a "Mini-AB" jack, systems with
# both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG).
#
menuconfig USB_GADGET
tristate "USB Gadget Support"
select USB_COMMON
select NLS
help
USB is a host/device protocol, organized with one host (such as a
PC) controlling up to 127 peripheral devices.
The USB hardware is asymmetric, which makes it easier to set up:
you can't connect a "to-the-host" connector to a peripheral.
Linux can run in the host, or in the peripheral. In both cases
you need a low level bus controller driver, and some software
talking to it. Peripheral controllers are often discrete silicon,
or are integrated with the CPU in a microcontroller. The more
familiar host side controllers have names like "EHCI", "OHCI",
or "UHCI", and are usually integrated into southbridges on PC
motherboards.
Enable this configuration option if you want to run Linux inside
a USB peripheral device. Configure one hardware driver for your
peripheral/device side bus controller, and a "gadget driver" for
your peripheral protocol. (If you use modular gadget drivers,
you may configure more than one.)
If in doubt, say "N" and don't enable these drivers; most people
don't have this kind of hardware (except maybe inside Linux PDAs).
For more information, see <http://www.linux-usb.org/gadget> and
the kernel documentation for this API.
if USB_GADGET
config USB_GADGET_DEBUG
bool "Debugging messages (DEVELOPMENT)"
depends on DEBUG_KERNEL
help
Many controller and gadget drivers will print some debugging
messages if you use this option to ask for those messages.
Avoid enabling these messages, even if you're actively
debugging such a driver. Many drivers will emit so many
messages that the driver timings are affected, which will
either create new failure modes or remove the one you're
trying to track down. Never enable these messages for a
production build.
config USB_GADGET_VERBOSE
bool "Verbose debugging Messages (DEVELOPMENT)"
depends on USB_GADGET_DEBUG
help
Many controller and gadget drivers will print verbose debugging
messages if you use this option to ask for those messages.
Avoid enabling these messages, even if you're actively
debugging such a driver. Many drivers will emit so many
messages that the driver timings are affected, which will
either create new failure modes or remove the one you're
trying to track down. Never enable these messages for a
production build.
config USB_GADGET_DEBUG_FILES
bool "Debugging information files (DEVELOPMENT)"
depends on PROC_FS
help
Some of the drivers in the "gadget" framework can expose
debugging information in files such as /proc/driver/udc
(for a peripheral controller). The information in these
files may help when you're troubleshooting or bringing up a
driver on a new board. Enable these files by choosing "Y"
here. If in doubt, or to conserve kernel memory, say "N".
config USB_GADGET_DEBUG_FS
bool "Debugging information files in debugfs (DEVELOPMENT)"
depends on DEBUG_FS
help
Some of the drivers in the "gadget" framework can expose
debugging information in files under /sys/kernel/debug/.
The information in these files may help when you're
troubleshooting or bringing up a driver on a new board.
Enable these files by choosing "Y" here. If in doubt, or
to conserve kernel memory, say "N".
config USB_GADGET_VBUS_DRAW
int "Maximum VBUS Power usage (2-500 mA)"
range 2 500
default 2
help
Some devices need to draw power from USB when they are
configured, perhaps to operate circuitry or to recharge
batteries. This is in addition to any local power supply,
such as an AC adapter or batteries.
Enter the maximum power your device draws through USB, in
milliAmperes. The permitted range of values is 2 - 500 mA;
0 mA would be legal, but can make some hosts misbehave.
This value will be used except for system-specific gadget
drivers that have more specific information.
config USB_GADGET_STORAGE_NUM_BUFFERS
int "Number of storage pipeline buffers"
range 2 256
default 2
help
Usually 2 buffers are enough to establish a good buffering
pipeline. The number may be increased in order to compensate
for a bursty VFS behaviour. For instance there may be CPU wake up
latencies that makes the VFS to appear bursty in a system with
an CPU on-demand governor. Especially if DMA is doing IO to
offload the CPU. In this case the CPU will go into power
save often and spin up occasionally to move data within VFS.
If selecting USB_GADGET_DEBUG_FILES this value may be set by
a module parameter as well.
If unsure, say 2.
config U_SERIAL_CONSOLE
bool "Serial gadget console support"
depends on USB_U_SERIAL
help
It supports the serial gadget can be used as a console.
source "drivers/usb/gadget/udc/Kconfig"
#
# USB Gadget Drivers
#
# composite based drivers
config USB_LIBCOMPOSITE
tristate
select CONFIGFS_FS
depends on USB_GADGET
config USB_F_ACM
tristate
config USB_F_SS_LB
tristate
config USB_U_SERIAL
tristate
config USB_U_ETHER
tristate
config USB_U_AUDIO
tristate
config USB_F_SERIAL
tristate
config USB_F_OBEX
tristate
config USB_F_NCM
tristate
config USB_F_ECM
tristate
config USB_F_PHONET
tristate
config USB_F_EEM
tristate
config USB_F_SUBSET
tristate
config USB_F_RNDIS
tristate
config USB_F_MASS_STORAGE
tristate
config USB_F_FS
select DMA_SHARED_BUFFER
tristate
config USB_F_UAC1
tristate
config USB_F_UAC1_LEGACY
tristate
config USB_F_UAC2
tristate
config USB_F_UVC
tristate
select UVC_COMMON
config USB_F_MIDI
tristate
config USB_F_MIDI2
tristate
config USB_F_HID
tristate
config USB_F_PRINTER
tristate
config USB_F_TCM
tristate
# this first set of drivers all depend on bulk-capable hardware.
config USB_CONFIGFS
tristate "USB Gadget functions configurable through configfs"
select USB_LIBCOMPOSITE
help
A Linux USB "gadget" can be set up through configfs.
If this is the case, the USB functions (which from the host's
perspective are seen as interfaces) and configurations are
specified simply by creating appropriate directories in configfs.
Associating functions with configurations is done by creating
appropriate symbolic links.
For more information see Documentation/usb/gadget_configfs.rst.
config USB_CONFIGFS_SERIAL
bool "Generic serial bulk in/out"
depends on USB_CONFIGFS
depends on TTY
select USB_U_SERIAL
select USB_F_SERIAL
help
The function talks to the Linux-USB generic serial driver.
config USB_CONFIGFS_ACM
bool "Abstract Control Model (CDC ACM)"
depends on USB_CONFIGFS
depends on TTY
select USB_U_SERIAL
select USB_F_ACM
help
ACM serial link. This function can be used to interoperate with
MS-Windows hosts or with the Linux-USB "cdc-acm" driver.
config USB_CONFIGFS_OBEX
bool "Object Exchange Model (CDC OBEX)"
depends on USB_CONFIGFS
depends on TTY
select USB_U_SERIAL
select USB_F_OBEX
help
You will need a user space OBEX server talking to /dev/ttyGS*,
since the kernel itself doesn't implement the OBEX protocol.
config USB_CONFIGFS_NCM
bool "Network Control Model (CDC NCM)"
depends on USB_CONFIGFS
depends on NET
select USB_U_ETHER
select USB_F_NCM
select CRC32
help
NCM is an advanced protocol for Ethernet encapsulation, allows
grouping of several ethernet frames into one USB transfer and
different alignment possibilities.
config USB_CONFIGFS_ECM
bool "Ethernet Control Model (CDC ECM)"
depends on USB_CONFIGFS
depends on NET
select USB_U_ETHER
select USB_F_ECM
help
The "Communication Device Class" (CDC) Ethernet Control Model.
That protocol is often avoided with pure Ethernet adapters, in
favor of simpler vendor-specific hardware, but is widely
supported by firmware for smart network devices.
config USB_CONFIGFS_ECM_SUBSET
bool "Ethernet Control Model (CDC ECM) subset"
depends on USB_CONFIGFS
depends on NET
select USB_U_ETHER
select USB_F_SUBSET
help
On hardware that can't implement the full protocol,
a simple CDC subset is used, placing fewer demands on USB.
config USB_CONFIGFS_RNDIS
bool "RNDIS"
depends on USB_CONFIGFS
depends on NET
select USB_U_ETHER
select USB_F_RNDIS
help
Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
and Microsoft provides redistributable binary RNDIS drivers for
older versions of Windows.
To make MS-Windows work with this, use Documentation/usb/linux.inf
as the "driver info file". For versions of MS-Windows older than
XP, you'll need to download drivers from Microsoft's website; a URL
is given in comments found in that info file.
config USB_CONFIGFS_EEM
bool "Ethernet Emulation Model (EEM)"
depends on USB_CONFIGFS
depends on NET
select USB_U_ETHER
select USB_F_EEM
select CRC32
help
CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
and therefore can be supported by more hardware. Technically ECM and
EEM are designed for different applications. The ECM model extends
the network interface to the target (e.g. a USB cable modem), and the
EEM model is for mobile devices to communicate with hosts using
ethernet over USB. For Linux gadgets, however, the interface with
the host is the same (a usbX device), so the differences are minimal.
config USB_CONFIGFS_PHONET
bool "Phonet protocol"
depends on USB_CONFIGFS
depends on NET
depends on PHONET
select USB_U_ETHER
select USB_F_PHONET
help
The Phonet protocol implementation for USB device.
config USB_CONFIGFS_MASS_STORAGE
bool "Mass storage"
depends on USB_CONFIGFS
depends on BLOCK
select USB_F_MASS_STORAGE
help
The Mass Storage Gadget acts as a USB Mass Storage disk drive.
As its storage repository it can use a regular file or a block
device (in much the same way as the "loop" device driver),
specified as a module parameter or sysfs option.
config USB_CONFIGFS_F_LB_SS
bool "Loopback and sourcesink function (for testing)"
depends on USB_CONFIGFS
select USB_F_SS_LB
help
Loopback function loops back a configurable number of transfers.
Sourcesink function either sinks and sources bulk data.
It also implements control requests, for "chapter 9" conformance.
Make this be the first driver you try using on top of any new
USB peripheral controller driver. Then you can use host-side
test software, like the "usbtest" driver, to put your hardware
and its driver through a basic set of functional tests.
config USB_CONFIGFS_F_FS
bool "Function filesystem (FunctionFS)"
depends on USB_CONFIGFS
select USB_F_FS
help
The Function Filesystem (FunctionFS) lets one create USB
composite functions in user space in the same way GadgetFS
lets one create USB gadgets in user space. This allows creation
of composite gadgets such that some of the functions are
implemented in kernel space (for instance Ethernet, serial or
mass storage) and other are implemented in user space.
config USB_CONFIGFS_F_UAC1
bool "Audio Class 1.0"
depends on USB_CONFIGFS
depends on SND
select USB_LIBCOMPOSITE
select SND_PCM
select USB_U_AUDIO
select USB_F_UAC1
help
This Audio function implements 1 AudioControl interface,
1 AudioStreaming Interface each for USB-OUT and USB-IN.
This driver doesn't expect any real Audio codec to be present
on the device - the audio streams are simply sinked to and
sourced from a virtual ALSA sound card created. The user-space
application may choose to do whatever it wants with the data
received from the USB Host and choose to provide whatever it
wants as audio data to the USB Host.
config USB_CONFIGFS_F_UAC1_LEGACY
bool "Audio Class 1.0 (legacy implementation)"
depends on USB_CONFIGFS
depends on SND
select USB_LIBCOMPOSITE
select SND_PCM
select USB_F_UAC1_LEGACY
help
This Audio function implements 1 AudioControl interface,
1 AudioStreaming Interface each for USB-OUT and USB-IN.
This is a legacy driver and requires a real Audio codec
to be present on the device.
config USB_CONFIGFS_F_UAC2
bool "Audio Class 2.0"
depends on USB_CONFIGFS
depends on SND
select USB_LIBCOMPOSITE
select SND_PCM
select USB_U_AUDIO
select USB_F_UAC2
help
This Audio function is compatible with USB Audio Class
specification 2.0. It implements 1 AudioControl interface,
1 AudioStreaming Interface each for USB-OUT and USB-IN.
This driver doesn't expect any real Audio codec to be present
on the device - the audio streams are simply sinked to and
sourced from a virtual ALSA sound card created. The user-space
application may choose to do whatever it wants with the data
received from the USB Host and choose to provide whatever it
wants as audio data to the USB Host.
config USB_CONFIGFS_F_MIDI
bool "MIDI function"
depends on USB_CONFIGFS
depends on SND
select USB_LIBCOMPOSITE
select SND_RAWMIDI
select USB_F_MIDI
help
The MIDI Function acts as a USB Audio device, with one MIDI
input and one MIDI output. These MIDI jacks appear as
a sound "card" in the ALSA sound system. Other MIDI
connections can then be made on the gadget system, using
ALSA's aconnect utility etc.
config USB_CONFIGFS_F_MIDI2
bool "MIDI 2.0 function"
depends on USB_CONFIGFS
depends on SND
select USB_LIBCOMPOSITE
select SND_UMP
select SND_UMP_LEGACY_RAWMIDI
select USB_F_MIDI2
help
The MIDI 2.0 function driver provides the generic emulated
USB MIDI 2.0 interface, looped back to ALSA UMP rawmidi
device on the gadget host. It supports UMP 1.1 spec and
responds UMP Stream messages for UMP Endpoint and Function
Block information / configuration.
config USB_CONFIGFS_F_HID
bool "HID function"
depends on USB_CONFIGFS
select USB_F_HID
help
The HID function driver provides generic emulation of USB
Human Interface Devices (HID).
For more information, see Documentation/usb/gadget_hid.rst.
config USB_CONFIGFS_F_UVC
bool "USB Webcam function"
depends on USB_CONFIGFS
depends on VIDEO_DEV
depends on VIDEO_DEV
select VIDEOBUF2_DMA_SG
select VIDEOBUF2_VMALLOC
select USB_F_UVC
help
The Webcam function acts as a composite USB Audio and Video Class
device. It provides a userspace API to process UVC control requests
and stream video data to the host.
config USB_CONFIGFS_F_PRINTER
bool "Printer function"
select USB_F_PRINTER
depends on USB_CONFIGFS
help
The Printer function channels data between the USB host and a
userspace program driving the print engine. The user space
program reads and writes the device file /dev/g_printer<X> to
receive or send printer data. It can use ioctl calls to
the device file to get or set printer status.
For more information, see Documentation/usb/gadget_printer.rst
which includes sample code for accessing the device file.
config USB_CONFIGFS_F_TCM
bool "USB Gadget Target Fabric"
depends on TARGET_CORE
depends on USB_CONFIGFS
select USB_LIBCOMPOSITE
select USB_F_TCM
help
This fabric is a USB gadget component. Two USB protocols are
supported that is BBB or BOT (Bulk Only Transport) and UAS
(USB Attached SCSI). BOT is advertised on alternative
interface 0 (primary) and UAS is on alternative interface 1.
Both protocols can work on USB2.0 and USB3.0.
UAS utilizes the USB 3.0 feature called streams support.
source "drivers/usb/gadget/legacy/Kconfig"
endif # USB_GADGET
Codebase Browser
linux