This is a much better experience than the previous Qualcomm debug experience, which was a hand-rolled set of read/write/execute primitives exposed over USB. It was hilariously undersecured, allowing a few of us to continually get root on various Qualcomm models.
In seriousness, these debug ports are seriously lacking in most mobile chipsets. MediaTek still has the old-style approach in many of their devices, requiring some incantations which expose serial over USB, but not in the way you think -- it's serial over USB pins!
I've done tonnes of work with mobile chipsets and security and this seems like they've finally started down the road to making this functionality accessible. Don't be surprised if you don't see this supported out of the box in most places, though. Most OEMs will certainly disable this once they've adapted their bootloaders to it. The big G doesn't like debuggability in end user devices.
It will be really interesting to see what production devices this is enabled on - It mentions the OnePlus 6 at least which has it fused out but is still accessible.
Edit: How are they reading the eFuses on a production OnePlus 6? Do they have a Qualcomm-signed EL3 EDL loader?
It seems to exist as qcom,msm-eud in the device tree of a (unfortunately production) SM4350 device I have along with an eud_enable_reg. Time to recompile the kernel with `/dev/mem`.
So just to get this straight, Qualcomm has a piece of custom silicon, as a peripheral controlled by registers, that when enabled reroutes the ARMs USB pins through it (adding a USB hub in the middle), and on that hub it adds a SWD programmer and a serial port that connect back to the ARM core's IOs? Amazing!
Different topic, but I was crazy impressed to see Qualcomm's dedication on getting USB audio offload going, having the audio device forward data to the USB host controller, for it to send it to the USB audio device.
Feels like a weird thing to spend so much effort optimizing but neat as heck to see. https://www.phoronix.com/news/Linux-6.16-USB-Audio-Offload