[PATCH V3 1/5] powerpc/fsl-pci: Unify pci/pcie initialization code

[Jia Hongtao-B38951]

> -----Original Message-----
> From: Kumar Gala [mailto:galak at kernel.crashing.org]
> Sent: Monday, July 30, 2012 10:47 PM
> To: Jia Hongtao-B38951
> Cc: Wood Scott-B07421; linuxppc-dev at lists.ozlabs.org; Li Yang-R58472
> Subject: Re: [PATCH V3 1/5] powerpc/fsl-pci: Unify pci/pcie
> initialization code
> 
> 
> On Jul 30, 2012, at 3:26 AM, Jia Hongtao-B38951 wrote:
> 
> >
> >
> >> -----Original Message-----
> >> From: Kumar Gala [mailto:galak at kernel.crashing.org]
> >> Sent: Saturday, July 28, 2012 5:17 AM
> >> To: Wood Scott-B07421
> >> Cc: Jia Hongtao-B38951; linuxppc-dev at lists.ozlabs.org; Wood Scott-
> B07421;
> >> Li Yang-R58472
> >> Subject: Re: [PATCH V3 1/5] powerpc/fsl-pci: Unify pci/pcie
> >> initialization code
> >>
> >>
> >> On Jul 27, 2012, at 3:24 PM, Scott Wood wrote:
> >>
> >>> On 07/27/2012 05:10 AM, Jia Hongtao-B38951 wrote:
> >>>> Hi kumar,
> >>>>
> >>>> I know "duplicate code from pci_process_bridge_OF_ranges()" is
> >>>> hard to accept but "refactor the code to have a shared function"
> >>>> is knotty. Actually this is the reason I didn't do the refactor.
> >>>
> >>> Maybe we should keep doing the init early?  We could still have a
> >>> platform device for the PM stuff, but some init would be done before
> >> probe.
> >>>
> >>> Another possibility is to try to handle swiotlb init later --
> possibly
> >>> by reserving memory for it if the platform indicates it's a
> possibility
> >>> that it will be needed, then freeing the memory if it's not needed.
> >>>
> >>> -Scott
> >>
> >> I think the first option seems reasonable.  Can we leave fsl_pci_init()
> >> as we now have it and just have the platform driver deal with PM
> restore
> >> via calling setup_pci_atmu() [probably need to update setup_pci_atmu
> to
> >> handle restore case, but seems like minor changes]
> >>
> >> - k
> >>
> >
> >
> > I think the second option is better if it's hard to decouple swiotlb
> > determination from pci init. I believe the better architecture that
> > PCI init in probe function of platform driver will bring us
> considerable
> > advantage. I really like to keep the completion of pci controller
> > platform driver not only for PM support but also for pci init.
> >
> > -Hongtao.
> >
> 
> Shifting of swiotlb init has a lot more issues.  Why do we need to do the
> PCI init in probe?
> 
> - k

I investigated the swiotlb init thing and found that in x86 swiotlb init is
done first and free if we don't need it.

-Hongtao.