Re: [PATCH v3 3/3] PCI: ARM: add support for generic PCI host controller

[Will Deacon <will.deacon@arm.com>]

On Tue, Feb 18, 2014 at 07:32:33PM +0000, Arnd Bergmann wrote:
> On Tuesday 18 February 2014 19:09:29 Will Deacon wrote:
> > 
> > > Regarding the 0x6200.. There are two conflicting issues there 
> > >  - You really don't want to let the PCI core assign resources to that
> > >    range, it probably won't work.
> > 
> > Right, with kvmtool we don't support resource assignment (the BARs are fixed)
> > so everything is PCI_PROBE_ONLY.
> 
> Ok, I looked at the source now and can confirm:
> 
> * 0x0-0x1000 are used for lots of legacy ISA devices.
> * PCI devices get assigned IO addresses in 0x400 steps starting at 0x6200.
> * There are three PCI drivers doing this: VESA, PCI-SHMEM and virtio-pci.
> 
> Regarding the PCI_PROBE_ONLY flag, how do you set that? Should we
> have a standard DT property for that? On PowerPC we already specified
> "linux,pci-probe-only" and "linux,pci-assign-all-buses", which seems
> reasonable to use in architecture independent code as well.

For arch/arm/ it's done on the command line (pci=firmware) but yes, for the
generic driver it sounds like a good idea to put this in the device-tree.
I'll look at adding the ppc properties in the next version.

Cheers,

Will