Doesn't support CH32 with probe-rs

[jonathanherbstgrapple]

I've been playing around with a WCH32 board. It has an onboard debugger which works with probe-rs, but when I try to run with the rusty probe I get this.

probe-rs run --chip CH32V307 target/riscv32imafc-unknown-none-elf/debug/blinky
Error: Connecting to the chip was unsuccessful.

Caused by:
    0: An error with the usage of the probe occurred
    1: The selected probe does not support the 'RISC-V' interface.

[korken89]

It has not implemented that interface, only SWD / JTAG is supported by hardware.
If you know how to implement the debug protocol used by the WCH32 series I'd welcome a PR to implement support!

[jonathanherbstgrapple]

It looks like their protocol is SWD, that's why I made a ticket here. Now, I'm not sure if it's a different brand of SWD than ARM SWD, but I wonder if probe-rs doesn't try because of some configuration that's communicated to it.

[korken89]

Ah alright! I can't find if it's ADI v5 they implement, probably needs more looking.

[Yatekii]

The selected probe does not support the 'RISC-V' interface. is JTAG not SWD :)

[Tiwalun]

As far as I remember, it is not SWD but their custom protocol, which is almost SWD.

It's this one, I think: https://perigoso.github.io/rins/rvswd/index.html

[Yatekii]

Oh, I was sure RISC-V was always JTAG. I am sorry.

[jonathanherbstgrapple]

So this is something that WCH came up with and not a RISC-V standard?

[korken89]

@jonathanherbstgrapple Looks like it, but the format looks very similar to SWD, extending with this support should be quite straight forward - at least for the bit-banged driver.
From a glance it seems like the SWD PIO driver would need modifications, but that needs a closer look.