On 2015/6/3 18:03, Lorenzo Pieralisi wrote:
> 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.
Hi Lorenzo,
I have thought to consolidate pci_controller for x86 and ia64,
but that will make the change set much more bigger. How about to
consolidate pci_controller by another patch set. That will be easier
for review.
Thanks!
Gerry
>
> Lorenzo
>
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