Re: [Patch v7 4/7] PCI/ACPI: Add interface acpi_pci_root_create()

Tomasz Nowicki
2015-11-27T07:01:13Z

On 20.11.2015 11:18, Lorenzo Pieralisi wrote:
> Hi Jiang,
>
> On Sat, Nov 14, 2015 at 01:49:08AM +0800, Jiang Liu wrote:
>
> [...]
>
>>> Not really. My concern is that there might be platforms out there with
>>> an offset between the CPU and PCI physical address spaces, and if we
>>> remove the offset value in acpi_decode_space we can break them,
>>> because in the kernel struct resource data we have to have CPU physical
>>> addresses, not PCI ones. If offset == 0, we are home and dry, I do not
>>> understand why that's a given, which is what we would assume if Jiang's
>>> patch is merged as-is unless I am mistaken.
>> We try to exclude offset from struct resource in generic ACPI code,
>> and it's the arch's responsibility to decide how to manipulate struct
>> resource object if offset is not zero.
>>
>> Currently offset is always zero for x86, and IA64 has arch specific
>> code to handle non-zero offset. So we should be safe without breaking
>> existing code. For ARM64, it's a little different from IA64 so it's
>> hard to share code between IA64 and ARM64.
>
> Can you drop the patch on the mailing lists please, we actually need it
> to get ACPI ARM64 PCIe support in the kernel, please let me know how
> you want to handle this and if you need any help.
>

Kindly reminder.

Regards,
Tomasz