On 3 Mar 2021, at 14:09, Ilia Mirkin <[email protected]> wrote:
> On Wed, Mar 3, 2021 at 5:30 AM Karol Herbst <[email protected]> wrote: >> >> >> Usually drivers map PCIe bars into the VM and read/write at certain offsets >> to do.. stuff. In the linux kernel we have the mmiotrace tracer in order to >> capture what a driver does with the hardware. You still need to interpret >> the trace file, but at least this should give you the raw data on what's >> going on. Hope that helps. > > Here's a good guide on how to use mmiotrace. It's nvidia-focused, but > the same steps would apply to any driver: > https://wiki.ubuntu.com/X/MMIOTracing > > Basically, start mmiotrace, load target driver, do some stuff, stop > mmiotrace, analyze the resulting trace. > > We have some tooling to help with that -- envytools/rnn/demmio will > parse the mmiotrace against a given rnndb (also in envytools). You > won't be able to reuse our rnndb, but you'd be able to build up your > own. You also wouldn't be able to use demmio directly, but you could > see how it works and modify it to your hw's needs. (e.g. it waits for > a read of the "0" mmio reg to determine which chip is being traced, > and loads up the appropriate rnndb settings - that won't work with > your hw out of the box.) > Thank you to both of you for the very useful tips and the link to this tutorial. This was exactly what I was looking for. >>> Also, the long term goal of this project would be to have this driver >>> merged into mainline, so what is allowed or not while doing this to avoid >>> problematic legal ramifications ? > > This isn't legal advice (for that, consult a lawyer), however a few > things that are definitely going to get you into trouble: > > - stealing (or using stolen) documentation > - de-compiling target driver and copying its implementation (as that > would be subject to copyright) Yes, I’m not using anything stolen (all the resources I have are publicly available on the card producer’s website). I’ve also contacted local open-source NGOs about the legal questions, I live in France and the law here is quite different to the US for those kind of things. Regards. Tomek _______________________________________________ Nouveau mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/nouveau
