Re: MI overrides of bus_dma(9), bus_space(9), pci(9)

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

>> That depends.
>
> On what?

Details of architectures and buses.

>> And this answer has never been answered.  This is why we have all the
>> messy MD bus code like rbus...
>
> I disagree (not on messy, MD, rbus, but on above question being unanswerable
> having anything to do with it).
>
>> > nor why you would want to do this at all.
>>
>> Because NetBSD/arm (imx31) had no bus_space_mmap(9).  See
>
> Ah, for mmap - but architectures with multiple MMUs there might not
> be a single answer, and if there is, it might not stay constant infinitely.

I don't know how multiple MMUs work.  Could you elaborate it?  Is
having multiple MMUs the only problem?  If so, that answers part of my
question.

Masao