Re: Porting to my custom 030 board

[Lawrence Manning <lawrence%aslak.net@localhost>]

Hi Chris,

Thanks for the mail and your interest in my board, and desire to get
NetBSD working on it. I've had a very brief look at 11 but still can't
really figure out how to begin my own porting effort. Do you have a
set of changes which just add support for a new machine? Ideally
something m68k, but I might glean some knowledge looking at another
machine type.

FWIW my offer is still open, but I can gather from the lack of
interest that either not enough skilled people are interested in such
a board, or that they know it would be a reasonable amount of work
even for them?

Cheers,

Lawrence

On Wed, Oct 1, 2025 at 12:59 AM Chris Hanson <cmhanson%eschatologist.net@localhost> wrote:
>
> On Feb 25, 2025, at 2:49 AM, Lawrence Manning <lawrence%aslak.net@localhost> wrote:
> >
> > The amount
> > of repetition across sys/arch generally is surprising and
> > disapointing. Likewise the lack of a clear hierarchy from processor
> > architecture down to board or "computer type" is also surprising. I'm
> > sure it's all done for logical reasons, but the barrier is
> > surprisingly high, for me.
>
> To resurrect this old thread, I think what's making it a little more confusing than it needs to be is your expectation that there's a hierarchy from processor architecture to machine. While it's unfortunate that they're mixed together under sys/arch, in NetBSD the processor architecture and machine are really fairly orthogonal: For the most part the code that's used for interfacing with a specific peripheral is the same across machines, and the code that's used for dealing with specific processor architecture is also the same across machines, and in both cases they're at least partially if not mostly de-duplicated.
>
> There has also been a lot more work done in the past couple years, including a bunch after your post, to further consolidate code including for the 68K architecture. If you look now at the NetBSD 11 branch you should hopefully see a lot less duplication than in the NetBSD 10 branch, and less still in trunk. Also, some of what looks like duplication may actually be indirection, where there's a driver with a common name that handles the slight differences between machines that use the same peripherals, but mostly calls through to that peripheral's driver. (No doubt there's more deduplication to be done in that area too.)
>
> For your specific board, you should be able to make use of mostly generic drivers and mostly generic 68030 processor support; the contents of your specific sys/arch/maxi030 machine's directory should be almost as thin as they are for (say) sys/arch/virt68k, and should mostly involve what's needed to glue the busses together and declare the addresses of the peripherals.
>
>   -- Chris
>