# 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 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