I am looking for some tutorials where writing LKM for some specific device has been taught.I learned basic of writing LKM but wanted to see how to write LKM for some device(fpga device or Network device). I know for writing LKM for device one need to know characteristics of a device.
But what could be characteristics of an FPGA device or Network device and how access them through LKM.
So,can anyone let me know what all are required to write a LKM for device?
Specifically to start learning to write Linux kernel networking drivers,
the following 2 tutorials should get you started.
Simple network driver for Realtek 8139
Network driver for AT91SAM9263 from scratch
Related
I would like to undertake a low level approach to transferring data from an FPGA to the STM32MP1 processor, I'm currently using an FTDI USB device which is an extra IC consuming power on my battery power device.
I would initialise and read data from the QUADSPI peripheral on the STM32 in dual bank mode.
I have been reading into kernel modules to gain register level access however they all seem to stop at Hello World or best toggling GPIO pins. I can't find any solid documentation for what I'm trying to do.
What is the best way to initialise a peripheral that has no Linux driver written for it?
I have an "off the shelf" commercial software using an ANT USB dongle to communicate with a cycling trainer.
My trainer is not compatible with the software because the protocol is slightly different (not a lot).
My goal is to write a protocol translator. The only thing I can think of is to write a UMDF virtual device driver (like Magic ISO Virtual DVD) looking like an ANT USB Device in the device manager (same PID\VID) while connecting itself to the physical ANT device. The virtual device driver will perform the protocol translation.
I looked at several examples from Microsoft here https://github.com/Microsoft/Windows-driver-samples but I was unable to find anything relevant. I thought this example would be a good start https://github.com/Microsoft/Windows-driver-samples-master/Sensors/CustomSensors but it is impossible to load the driver using the given procedure from the inf file.
BTW I am familiar with the content of INF files and the basics of KMDF & UMDF device drivers programming. My problem is to write something that will load in the device manager and present itself as a real USB device even if it is not enumerated by the USB bus subsystem.
Can anybody with driver development experience point me to some relevant code sample or documentation?
Best regards !
I am currently developing a UMDF CCID (smartcard reader) driver. This project helped me at the beginning because it compiles out of the box and creates virtual device nodes (smartcard readers) visible in the device manager.
I'm trying to learn Unix kernel development and I'm asked to "play around with the usb driver code and learn things".
where should I start?
Thanks in advance!
First go through basics of USB
Try to understand USB document from free electronic website
After that go to Linux kernel document
Continuously try to go through Linux kernel codes in USB module and corelate with document contains.
If any board is available then try to put debugs in kernel code, dump to board and observe the code flow for different USB devices.
I think you should start with learning USB protocol first and then analysing usb linux drivers. Read the usb specifications from www.usb.org.
I have a USB device for which I have an API. This API only works if the USB device doesn't use the ftdi_sio/usbserial drivers.
On my laptop, if I plug the USB device in, these drivers get loaded (as modules) and I have to unload them using modprobe -r after which code using the API can see the device.
I have another device which experiences the same issue although no modules are loaded so I'm guessing these drivers are compiled into the kernel. My question is this - is there any way to stop this device from using these drivers or do I have to recompile the kernel, etc?
Thanks for any help!
You are essentially looking for a way to :
unbind the default driver from your USB device
and
bind a driver of your choice to it.
Take a quick look at this to get you started.
A slightly more detailed description of the same is available in this excellent LWN article of (un)binding device drivers.
We are creating small system which has GPS receiver and PC. We want to test my GPS receiver, We do not want to go for a driver on the first go. First I would like to test my circuit works or nor. GPS IC has been set to output NMEA sentence. We want a program which just reads data from USB port and print it on the screen.
Can we write something like this easily ? Do we have any open source tool which will achieve this purpose ?
Platform : Windows 7
All devices need a driver, so I'm going to interpret your question as "how can I read NMEA data from my GPS using only drivers provided by the OS, so I don't have to write my own?"
If the GPS chip has a USB interface, then you should have gotten a driver with it. But most GPS chips have a UART interface which in your case sounds like it is connected to a separate USB-UART conversion chip. That conversion chip most likely came with a driver as well, but if not, you could jumper the reset pin of the converter chip, disabling it, and then attach a TTL/RS-232 level converter (available off-the-shelf) to the UART traces and then to your computer's serial port.
Unless you suspect that the driver for the USB-UART converter is causing problems, I wouldn't bother.
Anything connected via USB is a device. Devices require a device driver, period.
You might be able to get away with an existing driver built into Windows. This is how USB memory keys work for example - they present a generic device that looks like a removable disk, and Windows already includes the drivers for generic removable disks.
You would need to check the documentation for your device to see if it can emulate a device which already has drivers. Otherwise you must install the company's drivers, or you're out of luck.
Have a look at libusb. You should be able to read the data with that and a little code. (Yes, it's a driver. I take the question to mean "without writing a driver".)
You need a device driver for your device. Unless Windows already have a class driver for the device.
For USB devices on Windows 7 you can write a user-mode driver, see UMDF.