Re: [edk2-devel] [PATCH v6 1/1] DynamicTablesPkg: Exempt some _CPC field from checks

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Pierre,

Thank you for this patch.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

On 29/01/2024, 12:09, "Pierre Gondois" <pierre.gondois@arm.com <mailto:pierre.gondois@arm.com>> wrote:


When generating _CPC objects, some fields are mandatory by spec [1].
Some fields cannot be supported by a the Juno platform, which is used
to test the _CPC generation. Therefore, rely on the
PcdDevelopmentPlatformRelaxations Pcd to either:
- warn about the missing fields and and let the OS handle the
missing information
- consider the missing fields as an error


_CPC fields that are exempted from checks when the Pcd is set:
- PerformanceLimitedRegister
- ReferencePerformanceCounterRegister
- DeliveredPerformanceCounterRegister


[1] Cf. non-optional fields in:
ACPI 6.5, s8.4.6.1 '_CPC (Continuous Performance Control)'


Signed-off-by: Pierre Gondois <pierre.gondois@arm.com <mailto:pierre.gondois@arm.com>>
---


Notes:
v6:
Do not warn if one of the following fields is missing:
- HighestPerformanceBuffer
- NominalPerformanceBuffer
An error code should just be returned.


.../Library/Common/AmlLib/AmlLib.inf | 3 ++
.../Common/AmlLib/CodeGen/AmlCodeGen.c | 28 ++++++++++++++++---
2 files changed, 27 insertions(+), 4 deletions(-)


diff --git a/DynamicTablesPkg/Library/Common/AmlLib/AmlLib.inf b/DynamicTablesPkg/Library/Common/AmlLib/AmlLib.inf
index 6d0aa6ff934c..f269691864d4 100644
--- a/DynamicTablesPkg/Library/Common/AmlLib/AmlLib.inf
+++ b/DynamicTablesPkg/Library/Common/AmlLib/AmlLib.inf
@@ -71,6 +71,9 @@ [LibraryClasses]
BaseLib


MemoryAllocationLib






+[FixedPcd]


+ gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdDevelopmentPlatformRelaxations


+


[BuildOptions]


*_*_*_CC_FLAGS = -DAML_HANDLE






diff --git a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
index 6f3f46e3b1ed..22c2d598d0d8 100644
--- a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
+++ b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
@@ -3532,6 +3532,29 @@ AmlCreateCpcNode (
return EFI_INVALID_PARAMETER;


}






+ /// The following fields are theoretically mandatory, but not supported


+ /// by some platforms.


+ /// - PerformanceLimitedRegister


+ /// - ReferencePerformanceCounterRegister


+ /// - DeliveredPerformanceCounterRegister


+ /// Warn if BIT0 in PcdDevelopmentPlatformRelaxations is set, otherwise


+ /// return an error.


+ if (IsNullGenericAddress (&CpcInfo->PerformanceLimitedRegister) ||


+ IsNullGenericAddress (&CpcInfo->ReferencePerformanceCounterRegister) ||


+ IsNullGenericAddress (&CpcInfo->DeliveredPerformanceCounterRegister))


+ {


+ if ((PcdGet64 (PcdDevelopmentPlatformRelaxations) & BIT0) != 0) {


+ DEBUG ((


+ DEBUG_WARN,


+ "Missing PerformanceLimited|ReferencePerformanceCounter|"


+ "DeliveredPerformanceCounter field in _CPC object\n"


+ ));


+ } else {


+ ASSERT (0);


+ return EFI_INVALID_PARAMETER;


+ }


+ }


+


if ((IsNullGenericAddress (&CpcInfo->HighestPerformanceBuffer) &&


(CpcInfo->HighestPerformanceInteger == 0)) ||


(IsNullGenericAddress (&CpcInfo->NominalPerformanceBuffer) &&


@@ -3540,10 +3563,7 @@ AmlCreateCpcNode (
(CpcInfo->LowestNonlinearPerformanceInteger == 0)) ||


(IsNullGenericAddress (&CpcInfo->LowestPerformanceBuffer) &&


(CpcInfo->LowestPerformanceInteger == 0)) ||


- IsNullGenericAddress (&CpcInfo->DesiredPerformanceRegister) ||


- IsNullGenericAddress (&CpcInfo->ReferencePerformanceCounterRegister) ||


- IsNullGenericAddress (&CpcInfo->DeliveredPerformanceCounterRegister) ||


- IsNullGenericAddress (&CpcInfo->PerformanceLimitedRegister))


+ IsNullGenericAddress (&CpcInfo->DesiredPerformanceRegister))


{


ASSERT (0);


return EFI_INVALID_PARAMETER;


-- 
2.25.1







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