PrmPkg: Replace PcdPrmPlatformGuid with EDKII_DSC_PLATFORM_GUID

Bugzilla request https://bugzilla.tianocore.org/show_bug.cgi?id=2969
was recently completed which causes the PLATFORM_GUID value from the
DSC file to be placed into Autogen file .c & .h files. With this
change, the PRM Platform GUID can be directly matched to the DSC
PLATFORM_GUID value.

Cc: Andrew Fish <afish@apple.com>
Cc: Kang Gao <kang.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Benjamin You <benjamin.you@intel.com>
Cc: Liu Yun <yun.y.liu@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Ankit Sinha <ankit.sinha@intel.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/PrmPkg/Readme.md b/PrmPkg/Readme.md
index f340eeb642..4aec5982af 100644
--- a/PrmPkg/Readme.md
+++ b/PrmPkg/Readme.md
@@ -13,6 +13,10 @@ to be leveraged by platform firmware with minimal overhead to integrate PRM func
 formal design and is not validated at product quality. The development of this feature is shared in the edk2-staging

 branch to simplify collaboration by allowing direct code contributions and early feedback throughout its development.

 

+> **Use recent edk2/master** - This code makes use of a very recent change in edk2 BaseTools. Specifically, commit

+[b65afdd](https://github.com/tianocore/edk2/commit/b65afdde74d6c1fac1cdbd2efdad23ba26295808). Ensure you have that

+change to build the code in this repo as-is.

+

 > By default, the build makes use of a new ACPI OperationRegion type specifically introduced for PRM called

 `PlatformRtMechanism`. Support for this OperationRegion is planned for the next release of the ACPI specification.

 However, support for `PlatformRtMechanism` is already included in the iASL Compiler/Disassembler for early prototyping

@@ -100,14 +104,21 @@ The following list are the currently defined build flags (if any) that may be pa
 ### PRM Platform GUID

 **IMPORTANT**

 

-A configuration item that requires user attention is the PRM platform GUID. Each platform that uses PRM must be

-uniquely identifiable so that various instances of a PRM module can target the correct platform in PRM module updates.

+PRM has a concept of a "Platform GUID" which associates a specific platform with a set of PRM modules built for

+that platform. This GUID is used to ensure system compatibility for a given collection of PRM modules.

+

+Therefore, each PRM module must only target a single platform and each platform must have a unique GUID. Even if a

+PRM module is unchanged between two different platforms now, there is no guarantee that will remain the case so always

+assign a unique Platform GUID for each platform.

 

-To apply a unique platform GUID set the following PCD to a unique value in your platform DSC file.

-  ``gPrmPkgTokenSpaceGuid.PcdPrmPlatformGuid``

+The PRM Platform GUID is primarily used during PRM module runtime updates in the OS to ensure that the Platform GUID

+in the system's ACPI table (PRMT) matches the Platform GUID of the module requested for update. Even if runtime

+updates are not a planned feature for a given platform, still assign a unique Platform GUID for binary module

+identification (the Platform GUID is in the module's export descriptor) and to ensure such updates can be seamlessly

+supported in the future if needed.

 

-The default value assigned in [PrmPkg.dec](PrmPkg/PrmPkg.dec) is zero. By design, this is an invalid value that will

-cause an ASSERT if it is not updated.

+In the `PrmPkg` implementation, the Platform GUID is automatically derived from the PLATFORM_GUID in the DSC file of

+the package being built.

 

 ## Overview

 At a high-level, PRM can be viewed from three levels of granularity: