On Wed, Jun 03, 2015 at 10:36:19AM +0100, Jiang Liu wrote:
> On 2015/6/3 16:44, Hanjun Guo wrote:
> > On 2015???06???02??? 17:35, Lorenzo Pieralisi wrote:
> >> On Tue, Jun 02, 2015 at 07:12:53AM +0100, Jiang Liu wrote:
> >>> From: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> >>>
> >>> ARM64 ACPI based PCI host bridge init needs a arch dependent
> >>> struct pci_controller to accommodate common PCI host bridge
> >>> code which is introduced later, or it will lead to compile
> >>> errors on ARM64.
> >>>
> >>> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> >>> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> >>> CC: Arnd Bergmann <arnd@xxxxxxxx>
> >>> CC: Catalin Marinas <catalin.marinas@xxxxxxx>
> >>> CC: Liviu Dudau <Liviu.Dudau@xxxxxxx>
> >>> CC: Lorenzo Pieralisi <Lorenzo.Pieralisi@xxxxxxx>
> >>> CC: Will Deacon <will.deacon@xxxxxxx>
> >>> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> >>> ---
> >>> arch/arm64/include/asm/pci.h | 10 ++++++++++
> >>> 1 file changed, 10 insertions(+)
> >>>
> >>> diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
> >>> index b008a72f8bc0..70884957f253 100644
> >>> --- a/arch/arm64/include/asm/pci.h
> >>> +++ b/arch/arm64/include/asm/pci.h
> >>> @@ -10,6 +10,16 @@
> >>> #include <asm-generic/pci-bridge.h>
> >>> #include <asm-generic/pci-dma-compat.h>
> >>>
> >>> +struct acpi_device;
> >>> +
> >>> +struct pci_controller {
> >>> +#ifdef CONFIG_ACPI
> >>> + struct acpi_device *companion; /* ACPI companion device */
> >>> +#endif
> >>> + int segment; /* PCI domain */
> >>> + int node; /* NUMA node */
> >>> +};
> >>
> >> There is nothing ARM64 specific in this structure. The only
> >> reason I see you want to keep it arch specific is the iommu
> >> pointer on x86,
> >
> > And also plarform_data for IA64 too.
> >
> >> but I think we should find a way to make
> >> the common bits shared across archs (ie the struct above) and
> >> add (maybe a void*) to the generic struct to cater for arch
> >> specific data.
> >>
> >> Thoughts ?
> >
> > We discussed this already, it has limitations to make it
> > common to all archs, I think the limitation are:
> >
> > - struct pci_controller are also used for other archs
> > such as PowerPC and Tile, they will not use it for
> > ACPI purpose, so we can not used for all archs.
> >
> > - if we let struct pci_controller defined only for archs
> > using ACPI, such as introduce it in linux/acpi.h, we still
> > can not satisfy that the struct pci_controller is not
> > only used for ACPI case on x86, it will be used for
> > non-ACPI too.
> >
> > So it's pretty difficult to share it with across archs to me,
> > any more ideas?
> Hi Hanjun and Lorenzo,
> As mentioned by Hanjun, I have no idea yet about how to
> consolidating "struct pci_controller" further. One possible
> way is to move "struct pci_controller" related code into
> arch, but apparently that will reduce code reusing.
I guess you can't move that struct pci_controller to generic code
since it is present on other archs too (with completely different
members).
What you can do is creating a new struct (ie same purpose of pci_controller
with a different name) common to all archs that contains the common bits
+ a void* data that contains arch specific data, and convert x86 and ia64
to using it.
It is weird to be forced to declare a pci_controller structure in arm64
code with 0 arch specific data in it.
Lorenzo
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