Re: [PATCH v10 4/6] PCI: hisi: Add PCIe host support for HiSilicon SoC Hip05

[Zhou Wang <wangzhou1@hisilicon.com>]

On 2015/10/14 17:06, Arnd Bergmann wrote:
> On Wednesday 14 October 2015 16:59:03 Zhou Wang wrote:
>>
>> Hi Arnd,
>>
>> In Hip05 PCIe host, it uses GITS_TRANSLATER's address to get TLP package
>> which contains MSI address and MSI data, and then combine BDF and MSI data
>> to a 32 bit data which will be writen to GITS_TRANSLATER register of ITS.
>>
>> I think maybe this is a defect of our PCIe controller.
> 
> I'd consider it a bug in the firmware if this is not set up correctly
> before boot.
> 
>>> I don't think what you do here is safe because the 'reg' property
>>> of the MSI controller might point to the address that is used for
>>> the message directly.
>>
>> I see your point, however we must get address of GITS_TRANSLATER and
>> set it to PCIe host. How about adding necessary comments here?
> 
> This seems to just be static setup that should be done before Linux
> is even loaded. Any reason you can't do it that way?
>

There are some ITSs in Hip05-D02 platform, in fact, we can use any of them
as a msi-controller,  which we can configure in dts. I am afraid that
hard-setting the value in BIOS would lead to restrictions in terms of flexibility,
as with the current implementation the same BIOS-driver can fit different
DTS structures.

Regards,
Zhou

> 	Arnd
> 
> .
>