Re: [PATCH] soc: hisilicon: Support HCCS driver on Kunpeng SoC

["lihuisong (C)" <lihuisong@huawei.com>]

在 2023/5/4 21:16, lihuisong (C) 写道:
>
> 在 2023/4/25 21:19, Sudeep Holla 写道:
>> On Tue, Apr 25, 2023 at 09:00:31PM +0800, lihuisong (C) wrote:
>>> For firmware, DSD way is simpler and easier to manage these virtual 
>>> platform
>>> devices, and it's an usual way in kernel.
>> Any specific examples you are referring here. We had lots of debate when
>> DSD was introduced. It must be used only when there is no standard ACPI
>> way to achieve the same. But in this I don't (yet) think that is the 
>> case.
>> Further "simplicity" is remotely not the reason why you must use DSD.
>> So until you provide me technical reasons as why _CRS can't work, I
>> have to NACK this approach. DSD in this case seems like pure hack.
>>
>>> Driver only needs to get a fixed value, like pcc-id and type, here.
>>>
>> Yes and _CRS is used to get similar such properties in ACPI. It includes
>> normally MMIO and interrupts and since GAS supports PCC and _CRS can
>> contain GAS, you must simply use that.
> Hi Sudeep,
>
> I'm tring to use CRS with GAS to report PCC channel ID and get other 
> informations driver need by address.
> I found a way to obtain the generic register information according to 
> "Referencing the PCC address space" in ACPI spec.
> And driver also get the PCC generic register information successfully.
>
> But I don't know how to set and use the address in PCC register.
> Where should this address come from?
> It seems that ACPI spec is not very detailed about this.
> Do you have any suggestions?
>
> On the other hand, we think that System Memory space + method can also 
> achieve above goal.
> What do you think of that?
>
>
Hi Sudeep,

Can you give us some suggestions about above question and idea?

Looking forward to your reply.

/Huisong