Help - How to - BLE - realtek device - kernel 4.x vs 5.x

For Developers
1

Hi,
I lack both high and low level understanding of this.

Kernel 5.x appears btusb.c has been modified to support listed devices and btrtl.c/h have functions for same. openwrt does not support my BLE device, specifically rtl8761b.
If there is a way to force rtl8xxxu to recognize PID/VID and associate, will the BLE functions work?

Problem 1, I would like to patch 4.x kernel with these files. I do not know the process.
I have WSL running with gl imagemaker but everything is ipk. Where is process documented for me to learn and make custom firmware image?

Problem 2, where in gl image do I find the source code for BLE? I dont know where it lives in source tree? Please help. I see gl-ble-sdk/api packages that I can load, but it looks like only supports silabs chips. Do I need to mod this package instead?

Lack of understanding problem 3, are these dongles/bt devices simply communicating through a usb virtual serial port? and if so, besides enabling device & setting bits on or off, can all the BLE be performed within a single 'c' file? How would I get that c file compiled to ipk file for openWRT?

Thank you anyone in advance who helps me to understand big picture and small details.

I have MT300 units, and want to run BLE operations using dongles. I have realtek rtl8761b dongle and silabs thunderboards.

w/kind regards,
Rob

2

If you want to modify the kernel in any way, you'll need to compile OpenWrt from scratch. See the section "Using the toolchain" on https://openwrt.org/docs/guide-developer/start

3

Thanks, I have imagebuilder running, still lost in the maze. Spinning head, billions of questions, no tutorial!

4

No, imagebuilder isn't the same thing. Imagebuilder doesn't recompile the kernel or the toolchain, which is why I said that you need to compile OpenWrt from scratch.

5

Big picture question, is openWRT going to upgrade to 5.x kernel or is there some obvious reason why not?

6

OpenWrt has already been using 5.x for a while now.

7

Then I dont understand why btusb/btrtl files not present in openwrt kernel. These are in other linux kernels. All I see is rtl8xxxu as staging like driver with only a few VID/PIDs. ??

8

Ok, is there docker image for this somewhere?

9

Did you actually check what version of the 5.x - series those files were introduced? Kernel 5.4, for example, and 5.10 are not the same version and 5.10 can contain new files that weren't yet in 5.4.

I would hazard a guess that you only looked at the major version number, completely ignoring the minor one. I can see both btusb.c and btrtl.c/btrtl.h in 5.10 in the OpenWrt sources.

No idea, I don't use Docker.

10

Sounds like you are using some vendor SDK.