[PATCH 0/3] Add PCI domain support to R-Car drivers

[Liviu Dudau]

On Mon, Sep 22, 2014 at 12:40:42PM +0100, Phil Edworthy wrote:
> Hi Liviu,
> 
> On 22 September 2014 12:29, Liviu wrote:
> > On Mon, Sep 22, 2014 at 10:51:07AM +0100, Phil Edworthy wrote:
> > > The Renesas R-Car devices (r8a7790 and r8a7791) use two PCI controller
> > drivers,
> > > one for an external PCIe slot, the other for an internal PCI bridge to USB
> > > controllers.
> > >
> > > However, they currently do not work at the same time as they use the
> > same PCI
> > > domain and use the same root bus number. We can't use different root
> > bus numbers
> > > due to the way root bus numbers are assigned in pcibios_init_hw() in
> > > arch/arm/kernel/bios32.c.
> > >
> > > Since the two PCI controllers are completely independent, I think it makes
> > sense
> > > to use different PCI domains for them.
> > >
> > > I've marked the third patch as RFC as I am not sure of the impact of
> > enabling
> > > PCI domains for all ARM devices. In the march to 'one kernel to rule them
> > all',
> > > I steered clear of mach specific changes.
> > >
> > > These patches require the following patch from Liviu Dudau:
> > >   [PATCH v11 07/10] OF: Introduce helper function for getting PCI
> > domain_nr
> > > Based on comments on this patch from Jason Gunthorpe, there is still the
> > issue
> > > that the domain numbers may change depending on the ordering at probe
> > time.
> > > However, this can be fixed later on by adding the entries in the DT files.
> > 
> > Hi Phil,
> > 
> > I'm happy that you found use for my patch, but I can't help wondering if it is
> > not a better idea to convert your drivers to the whole new API in my series.
> > Do you have any thoughts on that?
> The main reason being that Renesas also supports the LTSI trees, so this fix
> will also need backporting to v3.10. 
> 
> > One other thing to note: Rob Herring is not very happy with the mix of OF
> > parsing and domain number allocation going in together, so I might remove
> > the
> > OF parsing entirely for now. Would that cause you any problems (other than
> > the fact that if of_pci_get_domain_nr() doesn't do anything OF related I
> > might
> > rename it to pci_get_domain_nr()). You don't seem to have any alias defined
> > for pci-domain in the DT, so I'll guess not.
> In the covering letter I mentioned that controllers should always use the same
> domain number, so I was planning to add pci-domain into the DTs later on.

Rob Herring seems to dislike the pci-domain alias solution, so it might have
to be a node in the host controller parent node, with linux,pci-domain.

Best regards,
Liviu

> 
> Thanks
> Phil


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