Re: [PATCH V2 4/6] PcAtChipsetPkg PcRtc: Use new EfiLocateFirstAcpiTable()

["Ni, Ruiyu" <ruiyu.ni@Intel.com>]

On 9/13/2018 6:26 PM, Star Zeng wrote:
> https://bugzilla.tianocore.org/show_bug.cgi?id=967
> Request to add a library function for GetAcpiTable() in order
> to get ACPI table using signature as input.
> 
> After evaluation, we found there are many duplicated code to
> find ACPI table by signature in different modules.
> 
> This patch updates PcatRealTimeClockRuntimeDxe to use new
> EfiLocateFirstAcpiTable() and remove the duplicated code.
> 
> Cc: Younas khan <pmdyounaskhan786@gmail.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> ---
>   PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c | 80 +---------------------
>   1 file changed, 3 insertions(+), 77 deletions(-)
> 
> diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> index 2105acf35f7b..7965eb8aa55b 100644
> --- a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> +++ b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.c
> @@ -1203,49 +1203,6 @@ IsWithinOneDay (
>   }
>   
>   /**
> -  This function find ACPI table with the specified signature in RSDT or XSDT.
> -
> -  @param Sdt              ACPI RSDT or XSDT.
> -  @param Signature        ACPI table signature.
> -  @param TablePointerSize Size of table pointer: 4 or 8.
> -
> -  @return ACPI table or NULL if not found.
> -**/
> -VOID *
> -ScanTableInSDT (
> -  IN EFI_ACPI_DESCRIPTION_HEADER    *Sdt,
> -  IN UINT32                         Signature,
> -  IN UINTN                          TablePointerSize
> -  )
> -{
> -  UINTN                          Index;
> -  UINTN                          EntryCount;
> -  UINTN                          EntryBase;
> -  EFI_ACPI_DESCRIPTION_HEADER    *Table;
> -
> -  EntryCount = (Sdt->Length - sizeof (EFI_ACPI_DESCRIPTION_HEADER)) / TablePointerSize;
> -
> -  EntryBase = (UINTN) (Sdt + 1);
> -  for (Index = 0; Index < EntryCount; Index++) {
> -    //
> -    // When TablePointerSize is 4 while sizeof (VOID *) is 8, make sure the upper 4 bytes are zero.
> -    //
> -    Table = 0;
> -    CopyMem (&Table, (VOID *) (EntryBase + Index * TablePointerSize), TablePointerSize);
> -
> -    if (Table == NULL) {
> -      continue;
> -    }
> -
> -    if (Table->Signature == Signature) {
> -      return Table;
> -    }
> -  }
> -
> -  return NULL;
> -}
> -
> -/**
>     Get the century RTC address from the ACPI FADT table.
>   
>     @return  The century RTC address or 0 if not found.
> @@ -1255,42 +1212,11 @@ GetCenturyRtcAddress (
>     VOID
>     )
>   {
> -  EFI_STATUS                                    Status;
> -  EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER  *Rsdp;
>     EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE     *Fadt;
>   
> -  Status = EfiGetSystemConfigurationTable (&gEfiAcpiTableGuid, (VOID **) &Rsdp);
> -  if (EFI_ERROR (Status)) {
> -    Status = EfiGetSystemConfigurationTable (&gEfiAcpi10TableGuid, (VOID **) &Rsdp);
> -  }
> -
> -  if (EFI_ERROR (Status) || (Rsdp == NULL)) {
> -    return 0;
> -  }
> -
> -  Fadt = NULL;
> -
> -  //
> -  // Find FADT in XSDT
> -  //
> -  if (Rsdp->Revision >= EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER_REVISION && Rsdp->XsdtAddress != 0) {
> -    Fadt = ScanTableInSDT (
> -             (EFI_ACPI_DESCRIPTION_HEADER *) (UINTN) Rsdp->XsdtAddress,
> -             EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE,
> -             sizeof (UINTN)
> -             );
> -  }
> -
> -  //
> -  // Find FADT in RSDT
> -  //
> -  if (Fadt == NULL && Rsdp->RsdtAddress != 0) {
> -    Fadt = ScanTableInSDT (
> -             (EFI_ACPI_DESCRIPTION_HEADER *) (UINTN) Rsdp->RsdtAddress,
> -             EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE,
> -             sizeof (UINT32)
> -             );
> -  }
> +  Fadt = (EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE *) EfiLocateFirstAcpiTable (
> +                                                         EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE
> +                                                         );
>   
>     if ((Fadt != NULL) &&
>         (Fadt->Century > RTC_ADDRESS_REGISTER_D) && (Fadt->Century < 0x80)
> 

Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

-- 
Thanks,
Ray