Re: [PATCH-RFC 1/2] tile: don't panic on iomap

From: Arnd Bergmann
Date: Wed Nov 30 2011 - 09:05:16 EST


On Wednesday 30 November 2011, Michael S. Tsirkin wrote:
> > > Presumably whoever wrote that architecture considered and discarded setting GENERIC_IOMAP.
> >
> > The tile PCI controller is apparently special in that it does not map the
> > PIO region into MMIO space, or make it available in any other way, so generic
> > iomap with IOCOND is pointless. Setting NO_IPORT will still mean that drivers
> > using ioport_map will not be built. This mostly impacts the legacy (non-AHCI)
> > ATA controllers, which I assume are not used on tile anyway.
>
> I don't object to setting NO_IPORT at all, but this won't help address
> the problem this patch is fixing, which is to use a generic pci_iomap
> on tile.

Ah, right. I didn't realize that the generic pci_iomap still attempts
to call ioport_map(). It would probably make sense to enclose
the ioport_map() call in pci_iomap() inside of #ifdef CONFIG_HAS_IOPORT.
It's not exactly beautiful, but probably the most correct solution
so that we can make any call to ioport_map() a build-time error on
architectures that set CONFIG_NO_IOPORT.

Arnd
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