Support USB DFU 1.1 Protocol & nRF53 chip

[Kemalele]

Hi!

I’ve been exploring the tock-bootloader and noticed that it currently implements USB CDC-ACM interface for some boards. However, I would like to explore the possibility of implementing USB DFU 1.1 instead. My goal is to enable firmware updates using dfu-util rather than tockloader. Additionally, I aim to ensure compatibility with the nRF53 series, particularly the nRF5340 chip.

Before diving into this, I’d like to ask:

Would implementing USB DFU 1.1 be feasible within the current architecture of tock and tock-bootloader?
Are there any known limitations or chip-specific quirks—particularly for the nRF53—that I should be aware of?

I’d appreciate any guidance or suggestions on how best to approach this!

[bradjc]

That would be very cool to have, and given that all bootloaders are doing generally the same thing I suspect it would be very feasible to implement. The Tock USB stack takes a second to get used to, but we have the CDC-ACM and HID implementations as examples.

tock-bootloader is just a minimal version of the Tock kernel that doesn't support applications, and I would imagine a different kernel (e.g., tock-usb-dfu) would implement USB DFU. The "tock bootloader" name implies the specific host-to-bootloader interface that tockloader uses. The USB DFU version would also be a little easier to setup I think for different boards because there would just be the USB stack and not the mix of USB and serial.