Re: [RFC v2 5/7] PCI/ACPI: Consolidate common PCI host bridge code into ACPI core

[Hanjun Guo]

On 2015å05æ13æ 20:24, Jiang Liu wrote:
> On 2015/5/13 17:29, Hanjun Guo wrote:
> > Hi Jiang,
> >
> > On 2015å05æ05æ 10:46, Jiang Liu wrote:
> > > Introduce common interface acpi_pci_root_create() and related data
> > > structures to create PCI root bus for ACPI PCI host bridges. It will
> > > be used to kill duplicated arch specific code for IA64 and x86. It may
> > > also help ARM64 in future.
> > [...]
> > > diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> > > index a965efa52152..a292ee33d74b 100644
> > > --- a/include/linux/pci-acpi.h
> > > +++ b/include/linux/pci-acpi.h
> > > @@ -52,6 +52,30 @@ static inline acpi_handle
> > > acpi_pci_get_bridge_handle(struct pci_bus *pbus)
> > >        return ACPI_HANDLE(dev);
> > >    }
> > >
> > > +struct acpi_pci_root;
> > > +struct acpi_pci_root_ops;
> > > +
> > > +struct acpi_pci_root_info_common {
> > > +    struct pci_controller        controller;
> >
> > There is another problem that this patch will lead to
> > compile error on ARM64 since ARM64 has basic ACPI support
> > in 4.1.
> >
> > struct pci_controller        controller is not available
> > on ARM64, that's the reason why compile errors happens on ARM64.
> >
> > How about move struct pci_controller to this head file?
> >
> > because all the related file you changed in this patch set
> > are only compiled when CONFI_ACPI=y, so for x86,
> >
> > struct pci_controller {
> > #ifdef CONFIG_ACPI
> >          struct acpi_device *companion;  /* ACPI companion device */
> > #endif
> > #ifdef CONFIG_X86_64
> >          void            *iommu;         /* IOMMU private data */
> > #endif
> >          int             segment;        /* PCI domain */
> >          int             node;           /* NUMA node */
> > };
> >
> > I'm sure #ifdef CONFIG_ACPI .. #endif can be removed
> > with no harm, and for *iommu, we can remove the #ifdef CONFIG_X86_64
> > with introducing little more memory on x86_32, after
> > that, the struct pci_controller is almost the same as ia64:
>
> On x86, struct pci_controller may be used when CONFIG_ACPI is disabled.
> So we can't move it into pci-acpi.h

Ah, ok, I missed this part.

> > struct pci_controller {
> >          struct acpi_device *companion;
> >          void *iommu;
> >          int segment;
> >          int node;               /* nearest node with memory or
> > NUMA_NO_NODE for global allocation */
> >
> >          void *platform_data;
> > };
> >
> > except void *platform_data;
> >
> > On ARM64, the structure is almost the same, so how about
> > introduce
> >
> > struct pci_controller {
> >          struct acpi_device *companion;  /* ACPI companion device */
> >          void            *iommu;         /* IOMMU private data */
> >          int             segment;        /* PCI domain */
> >          int             node;           /* NUMA node */
> > #ifdef CONFIG_IA64
> >      void *platform_data;
> > #endif
> > };
> >
> > in this file, then can be used for all architectures?
> Current mode is that architecture defines its own version of
> struct pci_controller. It would be better to keep this pattern.

OK, thanks for the clarify :) So how about add my basic
PCI support patch for ARM64 on top of you patch set to fix
this problem?

Thanks
Hanjun


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