Re: pci_mapreg_map and BAR from `Bus space tutorial'

[Radoslaw Kujawa <radoslaw.kujawa%c0ff33.net@localhost>]

Hi.

On 6/12/20 3:30 PM, Rocky Hotas wrote:
> I applied your patch and it works for me the same way. Thanks!

Excellent, glad to hear that.

> As a sidenote: I found your bus_space_tutorial very useful, the only one
> available about this topic. For this problem, I suspended it at slide
> 47 of your pdf.

There's also a good general tutorial about NetBSD drivers, by Jochen 
Kunz, that is referenced at the end of bus_space tutorial.

> My intention is to follow it entirely, and then to elaborate and expend
> it (adding comments, citations from the manpages), in order to keep a
> useful and up-to-date introduction for a newbie. Would you agree?

Yes, definitely.

Originally, the slides were used as a part of hands-on tutorial 
delivered by me during EuroBSDCon 2012 (and later for some commercial 
clients).

The slides were not designed as a stand-alone learning material - I just 
used them to track the progress of a live tutorial, and emphasize 
important areas. So slides obviously lack any background information or 
comments.

As you have probably noticed, the source to slides and examples is 
available on GitHub. However, if you are serious about expanding the 
tutorial please contact me off-list, as I am getting more and more 
hesitant to continue using GitHub for anything (I'll arrange a 
self-hosted repo).

> I hope to be able to follow the remainder of the tutorial by my own. But
> if some other problem could arise, can I contact you in future?
> Obviously only if and when strictly necessary.

Sure, feel free to contact me.

Due to time constraints, I cannot guarantee a timely response, but I am 
very much interested in any further problems, or general comments that 
you may have.

> P.S.
> I don't know if it's relevant, but something weird instead happens if I
> try to write 0xFFFFFFFF in the faa BAR.
> Before your patch, after the write, the BAR provided the value
> 0x0000FFF0: I was expecting 0xFFFFFFF0.
> After your patch, and after writing 0xFFFFFFFF, BAR showed an even weirder
> value: 0x000FFFFF. I used pcictl(8) for these operations. However, it all
> seems to work from the dmesg, so maybe they are due to the fact that
> this PCI device is not real.

I honeslty have no idea, debugging this would require digging into 
gxemul internals.

Best regards,
Radoslaw