Raw Gadget is a kernel module that allows to emulate USB devices from userspace
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Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#2Arguably this can be implemented already using usbip to localhost. That's already part of mainline, so does not need any out of tree modules.
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#3Neat. Can you clarify what "emulate" means? Would this let me implement a USB gadget on a Linux board with a device-side USB port, without writing a kernel module?
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#4Could this be useful to "mock" A USB device for integration testing hardware (or specifically writing specs against not-plugged-in-hardware)?
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#5A key bit of information that might clear up some confusion - USB gadgets are the main peripheral-side USB interface in the Linux kernel.
When you plug an embedded Linux device like a phone into something, it could use USB gadgets to expose internal storage as a mass storage device, create a tty and expose that as a USB ACM/CDC device, etc- and using the gadget mechanism, allocate USB endpoints to each of these functions, and enable or disable them at runtime.
So, this project seems to be allowing a Linux device to emulate arbitrary peripherals to an external USB host.
Prior work in this area: see Facedancer. Neat.
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#6Neat. Can you clarify what "emulate" means? Would this let me implement a USB gadget on a Linux board with a device-side USB port, without writing a kernel module?
That's already possible using usb functionfs.
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#7A key bit of information that might clear up some confusion - USB gadgets are the main peripheral-side USB interface in the Linux kernel. When you plug an embedded Linux device like a phone into something, it could use USB gadgets to expose internal storage as a mass storage device, create a tty and expose that as a USB ACM/CDC device, etc- and using the gadget mechanism, allocate USB endpoints to each of these funct…
No, this allows userspace to act as a USB gadget connected to the Linux kernel it's running on.
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#8A key bit of information that might clear up some confusion - USB gadgets are the main peripheral-side USB interface in the Linux kernel. When you plug an embedded Linux device like a phone into something, it could use USB gadgets to expose internal storage as a mass storage device, create a tty and expose that as a USB ACM/CDC device, etc- and using the gadget mechanism, allocate USB endpoints to each of these funct…
No, this allows userspace to act as a USB gadget connected to the Linux kernel it's running on.
It sure doesn't seem to.
That's why they have a separate subproject for it-
https://github.com/xairy/raw-gadget/blob/master/dummy_hcd/RE...
But you certainly could know more than me about it! Why do you think it's exclusively for acting as a USB gadget connected to the Linux kernel it's running on?
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#9Bit of clarification is apparently needed. The loopback USB emulation is already in mainline via CONFIG_USB_DUMMY_HCD
What this new module provides is new userspace API to the gadget subsystem, making the dummy hcd much more practical especially for testing USB driver code
Re: Raw Gadget is a kernel module that allows to emulate USB devices from userspace
#10This is really fantastic. I am currently building my own keyboard with my own controller and it will be much easier for me to first implement mock controller in userspace before I try to get it right on external device. Especially because I will want to put some complicated functionality in it like steno.