Re: [RFC v2 25/39] pcmcia: add HAS_IOPORT dependencies

[Maciej W. Rozycki]

On Wed, 4 May 2022, Arnd Bergmann wrote:

> >  POWER9 is another architecture with no port I/O space[1]:
> 
> POWER9 is just an implementation of the power architecture
> that has a particular PCI host bridge. I would assume that
> arch/powerpc/ would continue to set HAS_IOPORT because
> it knows how to access I/O ports at compile-time.

 Well, yes, except I would expect POWER9_CPU (and any higher versions we 
eventually get) to clear HAS_IOPORT.  Generic configurations (GENERIC_CPU) 
would set HAS_IOPORT of course, as would any lower architecture variants 
that do or may support port I/O (it's not clear to me if there are any 
that do not).  Ideally a generic configuration would not issue accesses to 
random MMIO locations for port I/O accesses via `inb'/`outb', etc. for 
systems that do not support port I/O (which it now does, or at least used 
to until recently).

  Maciej