On 2015/5/13 17:29, Hanjun Guo wrote:

Hi Jiang,

On 2015?05?05? 10:46, Jiang Liu wrote:

quoted

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.

[...]

quoted

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

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.
Thanks!
Gerry

Thanks
Hanjun