[PATCH v8 3/9] pci: Introduce pci_register_io_range() helper function.

Arnd Bergmann
2014-07-02T12:30:31Z

On Tuesday 01 July 2014 21:45:09 Liviu Dudau wrote:
> On Tue, Jul 01, 2014 at 09:36:10PM +0200, Arnd Bergmann wrote:
> > On Tuesday 01 July 2014 19:43:28 Liviu Dudau wrote:
> >
> > This still conflicts with the other allocator you have in patch 9
> > for pci_remap_iospace: nothing guarantees that the mapping is the
> > same for both.
> >
> > Also, this is a completely pointless exercise at this moment, because
> > nobody cares about the result of pci_address_to_pio on architectures
> > that don't already provide this function. If we ever get a proper
> > Open Firmware implementation that wants to put hardcoded PCI devices
> > into DT, we can add an implementation, but for now this seems overkill.
> >
> > The allocator in pci_register_io_range seems reasonable, why not merge
> > this function with pci_remap_iospace() as I have asked you multiple
> > times before? Just make it return the io_offset so the caller can
> > put that into the PCI host resources.
>
> Hi Arnd,
>
> While I agree with you that at some moment the allocators were inconsistent
> wrt each other, for this version I would respectfully disagree on this.
> The allocator in pci_register_io_range() only makes sure that the ranges
> are not overlapping, it doesn't do any mapping whatsoever, while
> pci_remap_iospace() does only an ioremap_page_range(). The idea is that
> you get the offset out of pci_address_to_pio() and apply it to
> pci_remap_iospace().

Ok, got it now, I'm sorry I didn't read this properly at first.

Your solution looks correct to me, just using different
tradeoffs to what I was expecting: You get a working pci_address_to_pio()
function, which is probably never needed, but in turn you need to
keep the state of each host bridge in a global list.

Arnd