[PATCH V5 3/3] powerpc/fsl-pci: Unify pci/pcie initialization code

Jia Hongtao-B38951 B38951 at freescale.com
Wed Aug 8 19:03:04 EST 2012



> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, August 07, 2012 11:25 PM
> To: Li Yang-R58472
> Cc: Wood Scott-B07421; linuxppc-dev at lists.ozlabs.org; Li Yang-R58472; Jia
> Hongtao-B38951
> Subject: Re: [PATCH V5 3/3] powerpc/fsl-pci: Unify pci/pcie
> initialization code
> 
> On 08/06/2012 11:20 PM, Li Yang wrote:
> > On Mon, Aug 6, 2012 at 11:09 PM, Scott Wood <scottwood at freescale.com>
> wrote:
> >> On 08/05/2012 10:07 PM, Jia Hongtao-B38951 wrote:
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Wood Scott-B07421
> >>>> Sent: Saturday, August 04, 2012 12:28 AM
> >>>> To: Jia Hongtao-B38951
> >>>> Cc: linuxppc-dev at lists.ozlabs.org; galak at kernel.crashing.org; Li
> >>>> Yang- R58472; Wood Scott-B07421
> >>>> Subject: Re: [PATCH V5 3/3] powerpc/fsl-pci: Unify pci/pcie
> >>>> initialization code
> >>>>
> >>>> As I explained before, this has to be done globally, not from the
> >>>> probe function, so we can assign a default primary bus if there
> isn't any ISA.
> >>>>  There are bugs in the Linux PPC PCI code relating to not having
> >>>> any primary bus.
> >>>>
> >>>> -Scott
> >>>
> >>> In my way of searching ISA you can also assign a default primary bus
> >>> in board specific files.
> >>
> >> That was meant for when the board file had an alternate way of
> >> searching for the primary bus (e.g. look for i8259), not as a
> >> replacement for the mechanism that guarantees there's a primary bus.
> >>
> >> You are causing a regression in the qemu_e500.c platform.
> >
> > Can we fix the qemu device tree to address the problem if we do make
> > it a rule to use the ISA node to indicate the primary bus?
> 
> No.  There is no ISA, and we're not going to lie and say there is.

But we can assign a default primary for qemu.

> 
> I really don't understand what the problem is with leaving the primary
> detection code as global.  Either fix the bugs so we don't need a primary,
> or accept some "impurity" in the workaround.
> 
> -Scott

Global detection for primary is ok but we think our way is deeper unified.

Is there any problem to fix the bugs?
I really don't understand why we have to need a primary bus.

-Hongtao.




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