Re: MinPlatformPkg/PlatformInit: FV code

["Yao, Jiewen" <jiewen.yao@intel.com>]

Ah, good catch.

That is correct - it is irrelevant to PEI. To put to FV Hob is enough, I believe.

Appreciate your careful review, which helps us clean up the code. :-)

Thank you
Yao Jiewen


> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Marvin H?user
> Sent: Saturday, February 3, 2018 2:30 AM
> To: edk2-devel@lists.01.org; Yao, Jiewen <jiewen.yao@intel.com>
> Subject: Re: [edk2] MinPlatformPkg/PlatformInit: FV code
> 
> Good point with the DxeCore, I didn't consider that. Though OsBoot would be
> irrelevant to the PEI phase, wouldn't it be?
> 
> Thanks,
> Marvin
> 
> From: Yao, Jiewen [mailto:jiewen.yao@intel.com]
> Sent: Friday, February 2, 2018 1:40 PM
> To: Marvin H?user <Marvin.Haeuser@outlook.com>; edk2-devel@lists.01.org
> Subject: RE: MinPlatformPkg/PlatformInit: FV code
> 
> Excellent question.
> 
> Comment inline.
> 
> From: Marvin H?user [mailto:Marvin.Haeuser@outlook.com]
> Sent: Wednesday, January 31, 2018 1:54 AM
> To: edk2-devel@lists.01.org<mailto:edk2-devel@lists.01.org>; Yao, Jiewen
> <jiewen.yao@intel.com<mailto:jiewen.yao@intel.com>>
> Subject: MinPlatformPkg/PlatformInit: FV code
> 
> Dear developers, dear Jiewen,
> 
> I have been investigating the devel-MinPlatform branch of edk2-platforms for
> educational purposes and got two questions regarding the Firmware Volume
> code in PlatformInitPreMem, if you do not mind. I assume the tree was tested, so
> most likely I misunderstood some things.
> 
> 
>   1.  Why is a Firmware Volume HOB built to cover the entire flash range
> (https://github.com/tianocore/edk2-platforms/blob/devel-MinPlatform/Platfor
> m/Intel/MinPlatformPkg/PlatformInit/PlatformInitPei/PlatformInitPreMem.c#L3
> 79)? Am I correct that this implies a FV spanning through the entire flash MMIO
> range, which would then imply all other FVs are contained within it? This would
> make sense, however that's not what I saw in the KabylakeOpenBoardPkg Flash
> Map, which has the NV Storage first
> (https://github.com/tianocore/edk2-platforms/blob/devel-MinPlatform/Platfor
> m/Intel/KabylakeOpenBoardPkg/Include/Fdf/FlashMapInclude.fdf#L25).
> 
> [Jiewen] You are right. We should not use FD region for FV. Will fix it.
> 
> 
> 
>   1.  Why are FV Info PPIs installed for the UefiBoot and the OsBoot FVs
> (https://github.com/tianocore/edk2-platforms/blob/devel-MinPlatform/Platfor
> m/Intel/MinPlatformPkg/PlatformInit/PlatformInitPei/PlatformInitPreMem.c#L3
> 44)? If I checked correctly, installing this PPI type will trigger PeiCore to dispatch
> PEIMs in the FVs, however there are only DXE drivers in these. Why are no FV
> HOBs installed, which are gotten by DxeCore?
> 
> [Jiewen] In DxeIpl, PeiServicesFfsFindNextVolume() is used to search DxeCore.
> In PeiCore, PeiFfsFindNextVolume() calls FindNextCoreFvHandle() for DxeCore
> one by one. If PcdFrameworkCompatibilitySupport is FALSE, it returns
> &Private->Fv[Instance] directly.
> 
> And Fv[Instance] is added in FirmwareVolmeInfoPpiNotifyCallback(), when
> gEfiPeiFirmwareVolumeInfo2PpiGuid is installed.
> 
> So if PcdFrameworkCompatibilitySupport is FALSE, install PPI is the only way to
> let PEI core discover DxeCore.
> Only if PcdFrameworkCompatibilitySupport is TRUE, install PPI is not required,
> but the FindNextCoreFvHandle() will install the PPI for the HobFv. The result is
> same.
> 
> 
> Thank you
> Yao Jiewen
> 
> 
> 
> 
> Thanks in advance for your time!
> 
> Best regards,
> Marvin.
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