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DynamicTablesPkg: Add AmlSetRdListCheckSum()

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Lists of Resource Data elements end with an EndTag (most of the time).
This function finds the EndTag (if present) in a list of Resource Data
elements and sets the checksum.

ACPI 6.4, s6.4.2.9 "End Tag":
"This checksum is generated such that adding it to the sum of all the data
bytes will produce a zero sum."
"If the checksum field is zero, the resource data is treated as if the
checksum operation succeeded. Configuration proceeds normally."

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
This commit is contained in:
Pierre Gondois
2021-10-08 15:46:16 +01:00
committed by mergify[bot]
parent 28b2df475f
commit 74addfeab6
2 changed files with 108 additions and 0 deletions
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32
DynamicTablesPkg/Library/Common/AmlLib/Utils/AmlUtility.h
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@@ -91,5 +91,37 @@ AmlPropagateInformation (
IN UINT8 NodeCount
);
/** Find and set the EndTag's Checksum of a list of Resource Data elements.
Lists of Resource Data elements end with an EndTag (most of the time). This
function finds the EndTag (if present) in a list of Resource Data elements
and sets the checksum.
ACPI 6.4, s6.4.2.9 "End Tag":
"This checksum is generated such that adding it to the sum of all the data
bytes will produce a zero sum."
"If the checksum field is zero, the resource data is treated as if the
checksum operation succeeded. Configuration proceeds normally."
To avoid re-computing checksums, if a new resource data elements is
added/removed/modified in a list of resource data elements, the AmlLib
resets the checksum to 0.
@param [in] BufferOpNode Node having a list of Resource Data elements.
@param [in] CheckSum CheckSum to store in the EndTag.
To ignore/avoid computing the checksum,
give 0.
@retval EFI_SUCCESS The function completed successfully.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_NOT_FOUND No EndTag found.
**/
EFI_STATUS
EFIAPI
AmlSetRdListCheckSum (
IN AML_OBJECT_NODE * BufferOpNode,
IN UINT8 CheckSum
);
#endif // AML_UTILITY_H_