DynamicTablesPkg: Add AmlGetEisaIdFromString() to AcpiHelperLib

Add a function converting a 7 characters string to its UINT32
EISAID. The algorithm used to create the EISAID is described
in the ACPI 6.4 specification, s19.3.4 "ASL Macros".

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>

DynamicTablesPkg/Include/Library/AcpiHelperLib.h

@@ -73,4 +73,21 @@ IsValidAcpiId (
   IN  CONST CHAR8  * Hid
   );
 
+/** Convert a EisaId string to its compressed UINT32 equivalent.
+
+  Cf. ACPI 6.4 specification, s19.3.4 "ASL Macros": "Eisaid"
+
+  @param  [in]  EisaIdStr   Input EisaId string.
+  @param  [out] EisaIdInt   Output EisaId UINT32 (compressed).
+
+  @retval EFI_SUCCESS             The function completed successfully.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+**/
+EFI_STATUS
+EFIAPI
+AmlGetEisaIdFromString (
+  IN  CONST CHAR8   * EisaIdStr,
+  OUT       UINT32  * EisaIdInt
+  );
+
 #endif // ACPI_HELPER_LIB_H_