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

[Bjorn Helgaas <bhelgaas@google.com>]

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.
> 
> 
> Phil Edworthy (3):
>   PCI: rcar-pcie: Add call to get domain nr
>   PCI: rcar-internal-pci: Add call to get domain nr
>   ARM: Enable PCI domains

I'm deferring these for now because they depend on Liviu's work, which I
haven't merged yet, and I suspect some minor adaptation will be required
here.

For what it's worth, I agree with Rob's hesitation about mixing lookup with
domain number allocation in of_pci_get_domain_nr().  That seems
unnecessarily complicated.

>  arch/arm/Kconfig                 | 2 +-
>  drivers/pci/host/pci-rcar-gen2.c | 6 ++++++
>  drivers/pci/host/pcie-rcar.c     | 9 ++++++---
>  3 files changed, 13 insertions(+), 4 deletions(-)
> 
> -- 
> 2.1.0
>