Re: [RFC] Add Platform Include path in modules

[Pankaj Bansal <pankaj.bansal@nxp.com>]

Hi All,

Will It violate the UEFI Platform Initialization Distribution Packaging Specification if we want to use Computed Includes ?
https://gcc.gnu.org/onlinedocs/gcc-3.0.2/cpp_2.html#SEC10

Thanks & Regards,
Pankaj Bansal

> -----Original Message-----
> From: Gao, Liming [mailto:liming.gao@intel.com]
> Sent: Tuesday, February 27, 2018 4:52 PM
> To: Pankaj Bansal <pankaj.bansal@nxp.com>; Kinney, Michael D
> <michael.d.kinney@intel.com>; Laszlo Ersek <lersek@redhat.com>; edk2-
> devel@lists.01.org
> Subject: RE: [edk2] [RFC] Add Platform Include path in modules
> 
> Hi,
>   For the first one, the same PCD can be configured to the different value for
> the different SkuId.
> 
> Here is wiki on structure pcd enable step and examples.
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> ub.com%2Flgao4%2Fedk2%2Fwiki%2FStructurePcd-Enable-
> Steps&data=02%7C01%7Cpankaj.bansal%40nxp.com%7C613339ac821e4bcc9
> fd508d57dd44781%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6
> 36553273075487313&sdata=DNiyfbhwN%2BKdFkltL%2FQQTzWFc8hhnNsXbC
> 4KjIHUy%2Bs%3D&reserved=0
> 
> TestPkg in
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> ub.com%2Flgao4%2Fedk2%2Ftree%2FUDK2018&data=02%7C01%7Cpankaj.b
> ansal%40nxp.com%7C613339ac821e4bcc9fd508d57dd44781%7C686ea1d3bc
> 2b4c6fa92cd99c5c301635%7C0%7C0%7C636553273075487313&sdata=8aBhP
> vNDkt%2FPb2kmAEXz0gERW9MFGD3kt8YcvjGi7jc%3D&reserved=0 has the
> sample case with structure pcd.
> 
> Thanks
> Liming
> >-----Original Message-----
> >From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> >Pankaj Bansal
> >Sent: Tuesday, February 27, 2018 3:40 PM
> >To: Kinney, Michael D <michael.d.kinney@intel.com>; Laszlo Ersek
> ><lersek@redhat.com>; edk2-devel@lists.01.org
> >Cc: Gao, Liming <liming.gao@intel.com>
> >Subject: Re: [edk2] [RFC] Add Platform Include path in modules
> >
> >Hi Laszlo/Michael,
> >
> >Thanks for your feedback on this proposal.
> >I looked at the structured PCDs and UEFI Platform Initialization
> >Distribution Packaging Specification.
> >Here is my take on these.
> >
> >1. structured PCDs are good if we want to declare single complex structure.
> >    But consider a case where I want to keep device information in structure.
> >(e.g. hardware settings, limitations etc)
> >    And we may want to tweak this information based on platform
> >revision being used.
> >    And different platforms can have different number of such devices.
> >    In this case, when we want to add a new platform, we might need to
> >introduce new PCDs in .dec files, which will not be needed for others.
> >    I don't know, will this even increase the PCD database size for
> >existing platforms or not ?
> >
> >2. To mitigate the "hidden" dependency of a module on platform, we can
> >explicitly declare this dependency in module inf file.
> >     I am thinking something like gEfiCallerIdGuid, i.e. module can
> >declare that that platform building(using) the module, supply this
> information.
> >
> >3. Using Libraries and Protocols can also solve such use cases. I just
> >felt that it's less cumbersome to use include files, and it also avoids code
> replication.
> >    Anyway, this is just my suggestion to have such mechanism in edk2
> >build process. I am more than happy to stick to platform libraries.
> >
> >Thanks & Regards,
> >Pankaj Bansal
> >
> >> -----Original Message-----
> >> From: Kinney, Michael D [mailto:michael.d.kinney@intel.com]
> >> Sent: Monday, February 26, 2018 10:56 PM
> >> To: Laszlo Ersek <lersek@redhat.com>; Pankaj Bansal
> >> <pankaj.bansal@nxp.com>; edk2-devel@lists.01.org; Kinney, Michael D
> >> <michael.d.kinney@intel.com>
> >> Cc: Gao, Liming <liming.gao@intel.com>
> >> Subject: RE: [edk2] [RFC] Add Platform Include path in modules
> >>
> >> Hi Pankaj,
> >>
> >> I agree with Laszlo that you should evaluate use of PCDs.  There are
> >> a few methods for a driver to use platform specific values/behavior.
> These are:
> >>
> >> * PCDs
> >> * Library class/Library Instance
> >> * Protocol/PPI
> >>
> >> One issue with the proposal is that it adds a hidden dependency to
> modules.
> >> An EDK II INF file describes the external interfaces of a module
> >> along with produces/consumes usage.  This information is aligned with
> >> the XML
> >schema
> >> that is documented in the UEFI Platform Initialization Distribution
> >> Packaging Specification.
> >>
> >>
> >>
> >https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fuefi
> .
> >>
> >org%2Fspecifications&data=02%7C01%7Cpankaj.bansal%40nxp.com%7C96c
> 4
> >>
> 2dd7271d449d56e908d57d3df2d4%7C686ea1d3bc2b4c6fa92cd99c5c301635
> >>
> %7C0%7C0%7C636552627376357192&sdata=sS7KT3haANF5TLHSeRGjIQHnLQ
> >> BtnTDLIZWntUhsk78%3D&reserved=0
> >>
> >> If two modules have the same GUID/Version, then the external
> >> interfaces
> >to
> >> those two modules are expected to be identical.
> >> With your proposal, two modules built for 2 different platforms would
> >> have the same GUID/Version but would not have the same external
> >> interfaces because a hidden dependency on a platform package was
> added.
> >>
> >> If a module really needs to use content from a platform package, then
> >> a
> >new
> >> copy of the module should be created with a new GUID/Version and the
> >> platform package added to the [Packages] section.  The other option
> >> is to
> >use
> >> one of the supported interfaces (PCDs, Lib, Protocol, PPI).
> >>
> >> Please let us know if any of these exiting methods do not work for
> >> your use case.
> >>
> >> Thanks,
> >>
> >> Mike
> >>
> >> > -----Original Message-----
> >> > From: Laszlo Ersek [mailto:lersek@redhat.com]
> >> > Sent: Monday, February 26, 2018 7:55 AM
> >> > To: Pankaj Bansal <pankaj.bansal@nxp.com>; Kinney, Michael D
> >> > <michael.d.kinney@intel.com>; edk2- devel@lists.01.org
> >> > Cc: Gao, Liming <liming.gao@intel.com>
> >> > Subject: Re: [edk2] [RFC] Add Platform Include path in modules
> >> >
> >> > On 02/26/18 11:55, Pankaj Bansal wrote:
> >> > > Hi,
> >> > >
> >> > > Consider a simple driver which needs that some data
> >> > structures be
> >> > > filled by the Platform, which is using the driver.
> >> > >
> >> > > Driver.c #include <Platform.h>
> >> > >
> >> > > Struct a = platformVal;
> >> > >
> >> > > We can define platformVal in Platform.h, which would
> >> > be unique to the
> >> > > platform being built. This Platform.h can be placed in
> >> > include
> >> > > directories, whose path would be defined in
> >> > Platform.dec file.
> >> > >
> >> > > Now, whenever we build driver for each unique
> >> > platform, we need not
> >> > > to mention Platform.dec file in driver.inf [packages]
> >> > section. We can
> >> > > append Platform.dec include paths to each driver. i.e.
> >> > look for the
> >> > > include files in [packages] section as well as in
> >> > Platform include
> >> > > directories.
> >> > >
> >> > > For this, I am looking for Platform.dec file in same
> >> > directory as
> >> > > Platform.dsc and using same name as Platform.dsc
> >> > >
> >> > > We can refine this change further. i.e. add Platform
> >> > include
> >> > > directories to driver's include paths based on some
> >> > condition in
> >> > > driver.inf file.
> >> >
> >> > (Apologies in advance if I failed to grasp the use
> >> > case.)
> >> >
> >> > If I understand correctly, you have multiple platforms (defined by
> >> > DSC and FDF files), and you build a given driver for several of
> >> > these platforms, separately. And, when building the driver for the
> >> > separate platforms, you'd like the driver to get different
> >> > initializers for various static (global) structure variables.
> >> >
> >> > Have you tried the structured PCD format? I think that could cover
> >> > your use case.
> >> >
> >> > Unfortunately I couldn't find anything about structured PCDs in the
> >> > edk2 specs, but there are several BZ references in the following
> >> > mailing list
> >> > message:
> >> >
> >> > [edk2] [Patch 00/14] Enable Structure PCD support in
> >> > edk2
> >> >
> >> >
> >>
> >https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmid
> .
> >> > mail-archive.com%2F1512140335-6932-1-git-send-
> >> &data=02%7C01%7Cpankaj.b
> >> >
> >>
> ansal%40nxp.com%7C96c42dd7271d449d56e908d57d3df2d4%7C686ea1d3b
> >> c2b4c6fa
> >> >
> >>
> 92cd99c5c301635%7C0%7C0%7C636552627376357192&sdata=iR50v%2F4Jg%
> >> 2BZQh7P
> >> > 1LB1bxeCryTangpA1SyVCwCEQW2U%3D&reserved=0
> >> > email-liming.gao@intel.com
> >> >
> >> > Thanks
> >> > Laszlo
> >_______________________________________________
> >edk2-devel mailing list
> >edk2-devel@lists.01.org
> >https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist
> >s.01.org%2Fmailman%2Flistinfo%2Fedk2-
> devel&data=02%7C01%7Cpankaj.bansal
> >%40nxp.com%7C613339ac821e4bcc9fd508d57dd44781%7C686ea1d3bc2b4
> c6fa92cd99
> >c5c301635%7C0%7C0%7C636553273075487313&sdata=CFicYp1LfCJDNiy1BV
> QHssZPLY
> >YT3bG6odDjBADql8I%3D&reserved=0