Hi Gerd,


Thanks,
Chao
On 2024/3/20 18:16, Gerd Hoffmann wrote:
> On Mon, Mar 18, 2024 at 04:28:17PM +0100, Gerd Hoffmann wrote:
>> On Sat, Mar 16, 2024 at 10:17:00AM +0800, lixianglai wrote:
>>> Hi Gerd:
>>>> On Mon, Mar 11, 2024 at 02:39:31AM -0700, Chao Li wrote:
>>>>> This library for PEI phase, and obtains the QemuFwCfg base address by
>>>>> directly parsing the FDT, reads and writes the data in QemuFwCfg by
>>>>> operating on the QemuFwCfg base address.
>>>>>   create mode 100644 OvmfPkg/LoongArchVirt/Library/FdtQemuFwCfgLib/FdtQemuFwCfgPeiLib.c
>>>>>   create mode 100644 OvmfPkg/LoongArchVirt/Library/FdtQemuFwCfgLib/FdtQemuFwCfgPeiLib.inf
>>>>>   create mode 100644 OvmfPkg/LoongArchVirt/Library/FdtQemuFwCfgLib/QemuFwCfgLibInternal.h
>>>>>   create mode 100644 OvmfPkg/LoongArchVirt/Library/FdtQemuFwCfgLib/QemuFwCfgPei.c
>>>> Is there anything LoongArch-specific in there?
>>> No,The main function of this lib library is to obtain the fwcfg base address by parsing fdt in the pei stage,
>>>   and provide access to fwcfg through mmio mode,
>>>   the difference between it and the existing library is that the fwcfg base address is not hard-coded in the compilation stage,
>>>   and is accessed through mmio rather than io port.
>> That would be the case for risc-v and aarch64 too, although I think they
>> don't need fw_cfg right now (they get all info needed via fdt).
> Oops, I was wrong, we have OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibMmio.inf

QemuFwCfgLibMmio.inf is looks like a DXE stage library, while this patch 
is the PEI stage library we are dicussing.

I have tow plans:

*Plan A:* Keep this library under LoongArchQemuVirt.

*Plan  B:* Create a new INF named QemuFwCfgPeiLibMmio.inf under 
OvmfPkg/Library/QemuFwCfgLib/, which will obtain the resources from FDT, 
and store them in the HOB or dynamic PCD.

Which one do you like? I'm leaning toward B because more people will be 
served if it's under OvmfPkg/Library.

>
> take care,
>    Gerd
>
>
>
> 
>


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