I have an Intel Edison that I would like to use as a USB device capable of responding to queries made by a host. Currently, it is serving as a USB device providing functionality such as a serial com port, and a filesystem (as well as providing power). I need a way to add an additional endpoint to this USB interface so that I can bind my own custom application to it and make it accessible by the host. Alternatively, I could create another virtual com port to communicate with the host over serial.
However, I have scoured the internet, and poured over libusb, and still have no idea as to how I would do this. For reference, the Edison runs a flavor of Linux called "Yocto."
Thanks
Related
As a web developer, I am new to USB and gadget development. I am creating a Windows Desktop application that communicates, using the Node-USB library, with a USB Device. To start, I am trying to create a mock USB device using Linux on my Raspberry Pi 4. I have set it up to boot as a USB device using this script, which is based on this guide, which sets the usb provider/vendor IDs, a rndis function, and more. Windows recognizes the device when plugging it into the computer, and I am able to open a connection to it using the NodeJS library.
I am now stuck on how to configure the device to set up a function that simply listens to data sent to it on a "bulk in" endpoint from the host, and echo it back automatically to the host, so that the Windows application receives it. I have been advised that there are many scripts available to set up a simple "demo" gadget like this on Linux, but I cannot find any.
It's not clear to me,
How to set up a usb function on the device to listen to a bulk "out" endpoint
How to set up a "driver" or a custom-made application to "listen" to the aforementioned function
How to make the listening application itself. The node-usb library says it's made for communicating with USB devices, not for devices itself, so it seems I can't use it?
Is there a simple bash script or built-in linux command that can automatically echo data to the host from the "in" endpoint?
I'd appreciate any guidance to point me in the right direction!
You need to write a USB function driver in kernel or use functionfs to do it in userspace. Either way you'll need to prepare USB descriptors which are presented to the host during enumeration (when your device is being plugged in) and then handle incoming USB requests on registered endpoints.
To setup one of the drivers already existing in kernel you can do it through configfs or using libusbgx wrapper library. There are also legacy function drivers which activate automatically after loading the module.
The node-usb library is wrapper for libusb, which is host-side library. So you're right, you cannot use it to create device-side function driver.
There is f_loopback function in kernel which does exactly what you need. This is probably the best starting point if you want to create your own USB function driver.
What I want to do:
An AI program on a host machine, reading inputs from a camera sensing the screen of the target machine and outputting controls to the target machine via USB connection--programming the host machine's USB host as a USB peripheral connected to the target machine.
What I want to do step by step: (is it possible to implement the steps below?)
Have a host machine A and a target machine B.
Connect A and B with a USB 3.0 Type-A male-male cable.
The USB connection shows up as an HID keyboard device on B.
Write code to simulate key presses on A that sends to B.
(Eg. calling press('F') on a program running on A would type F to B's input)
It shouldn't require any program installed on B.
What I already searched:
USB 3.0 Host to host connection is possible:
https://superuser.com/questions/795053/how-do-i-connect-two-computers-using-usb-3-0
USB 2.0 Host to host connection is impossible:
https://superuser.com/questions/99274/how-to-connect-two-computers-with-usb
Similar questions asked without the assumption that USB 3.0 Host to Host connection is possible:
https://superuser.com/questions/1128365/simulate-usb-keyboard-from-machine
Setting up a computer to act as an HID device connected to another computer via ps/2,usb or another wired connection
https://superuser.com/questions/507921/computer-to-act-as-keyboard?rq=1
Suggestions in ascending order of feasibility:
USB Gadgets
You are using linux, so the default way would be to create/configure/load a gadget driver. Have a look at this tutorial, though for a raspberry, should work on your PC too. However, I could not find any information regarding the use of USB3 - the tutorial assumes your host is using one of it's OTG ports, which your PC most likely does not have. So whether this works with your USB3.1 Type-A-to-Type-A connection you'll need to test.
USBIP
The idea of sharing USB devices (not just keyboards) is not really new. With USBIP you can "export" any local USB device to the network, and your client will need the client-side USBIP driver to access the keyboard.
Dont bother with USB at all, just use Ethernet
I'd simply write two userland scripts/programs that send/receive+execute the keystrokes. Very easy to implement, you're probably familiar with python anyway.
If you absolutely cant have software installed on the client-PC and your Type-C-to-Type-C connection doesnt support USB Gadgets, there's another way. It basically involves the use of two USB-to-serial adapters (~15$) and a serial cable. While this wont be enumerated as a keyboard, but rather as serial port, it's the lowest-effort solution to transfer data without additional software on the client. Both computers will just do file I/O. If your computers still have COM-ports, you can even omit the serial converters!
I'm trying to create a usb based ethernet device on my computer, basically I want to tell my computer (linux based) that one of its usb ports is actually an ethernet port. I have done extensive research and while it's supposed to be possible, I can't find any examples of code / commands to run.
According to wikipedia:
The USB-eth module in Linux makes the computer running it a variation of an Ethernet device that uses USB as the physical medium. It creates a Linux network interface, which can be assigned an IP address and otherwise treated the same as a true Ethernet interface. Any applications that work over real Ethernet interfaces will work over a USB-eth interface without modification, because they can't tell that they aren't using real Ethernet hardware.
So in theory, this should be possible, I just need some help or a gentle nudge in the right direction to get this thing rolling. What I'm NOT trying to do is plug a usb to ethernet dongle/adapter into my computer, I have several of those lying around and that doesn't help me out at all.
this is ethernet-over-usb
https://en.wikipedia.org/wiki/Ethernet_over_USB
without external hardware you can try the CDCether kernel module and ethtool ( then you can only connect to a usb device that operates in usb device mode )
( https://developer.ridgerun.com/wiki/index.php/How_to_use_USB_device_networking , http://tldp.org/HOWTO/Motorola-Surfboard-Modem/usb.html, http://www.linux-usb.org/usbnet/ )
else you need a physical adapter for this. the adapter translates between the protocols and the different hardware interfaces.
in usb protocol can only be one host in a network, therefore you need at least a host-to-host cable ( http://www.linux-usb.org/usbnet/ ) if you want to connect two usb host devices, i.e. two pcs
required kernel module ( driver ) when using a physical adapter is either usbnet ( with its minidrivers ) or usb-eth
I am on debian and:
I have a USB controller hooked up to a USB port on my PC (Device 1).
I have a male to male USB cord hooked up to another port on the PC that connects to Device 2. (it is a "bridging" usb cord, and has the chip for it)
I want to make them connect to each other as if they were one cord, so neither device knows that there is a computer in the middle.
This would be called a 'Coupler', except that I am using a PC as a coupler.
Here is a (really bad) diagram I made:
What I have done:
I have been able to connect the two devices independently of each other and sniff the results for when they fail to connect. The devices don't send a large volume of data back and forth.
Maybe there is some kind of command tool that I could use, for example (psudocode):
$ couple-usb-ports PORT1 PORT2
You're trying to reinvent the wheel here.
You might consider looking at this link instead.
http://dan3lmi.blogspot.com/2012/10/sniffing-usb-traffic-different.html
Specifically this.
Windows: You cannot directly capture raw USB traffic on Windows with Wireshark/WinPcap, but it is possible to capture and debug USB traffic on a virtual Windows machine under Oracle Virtual Box.
You cannot use a simple PC as transparent USB sniffer without extra (expensive) hardware. An USB bus has always one host (and one or more devices), and the PC can only be the host. This is a hardware limitation.
But you can capture USB data in a Windows machine using Wireshark and USBPcap, eliminating the need for the middle box in most cases.
As this post is tagged Linux, I suppose the controller PC is a Linux machine. Instead of connecting USB ports with a male-male connector, which is all kinds of bad (you are connecting the 5V lines of both machine with each other!), just run Wireshark in the controller PC.
There might be a little work to be done previously, as you have to enable Wireshark for USB monitoring (Particularly in Debian, this is disabled by default), and you might have to install a small driver to enable the monitoring. Have a look at this page for more information.
Once you get it working, Wireshark is an excellent tool for this!
I have a linux platform* that is connected as a usb device to an automotive device which acts as the USB host. The two devices should communicate over CDC/NCM, but the linux platform is not recognised by the automotive device and therefore the connection is not established. Surprisingly a connection to my computer is established correctly.
I now need to create a trace of that USB connection in order to check if there is an error in the USB handshake that can't be handled by the automotive device. As I cannot access the USB host, I need to create the trace from the gadget side.
I tried using usbmon and tcpdump, but this seems to work only for USB controllers configured as hosts on the tracing platform, not for ones configured as devices.
How can I configure usbmon to work also on devices?
If that is not possible are there any other possibilities to achieve this? (preferrably without hacking any drivers...)
Or do I have to use a Hardware USB sniffer?
BTW, all required modules (esp. g_ncm) are correctly loaded.
Thank you for your help!
stefan
*custom distribution on a freescale iMX6 processor (ARM), Kernel Version 3.0.35