Re: [RFC] SATA : Implemented NXP errata A008402

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

On 1/8/2018 7:16 PM, Meenakshi Aggarwal wrote:
> Description:
> Commands with 4 MB PRD length entries fail if PRD[DBC] is
> set to the value according to AHCI standard spec.
> Due to a logic error, 3F_FFFFh is misinterpreted by the
> device as zero length.

Is the logic error mentioned here is the error in HW?
Then I do not prefer to add such PCD for a HW workaround.

> 
> Workaround:
> Set PRD length to 0 when creating a PRD entry for
> a maximum data transfer size of 4 MB to fix the erratum.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
> ---
>   MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c           | 2 +-
>   MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.inf | 1 +
>   MdeModulePkg/MdeModulePkg.dec                              | 3 +++
>   3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
> index e6de5d6..fb6dc0b 100644
> --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
> +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c
> @@ -591,7 +591,7 @@ AhciBuildCommand (
>       if (RemainedData < EFI_AHCI_MAX_DATA_PER_PRDT) {
>         AhciRegisters->AhciCommandTable->PrdtTable[PrdtIndex].AhciPrdtDbc = (UINT32)RemainedData - 1;
>       } else {
> -      AhciRegisters->AhciCommandTable->PrdtTable[PrdtIndex].AhciPrdtDbc = EFI_AHCI_MAX_DATA_PER_PRDT - 1;
> +      AhciRegisters->AhciCommandTable->PrdtTable[PrdtIndex].AhciPrdtDbc = PcdGet32 (PcdPrdtMaxDataLength);
>       }
>   
>       Data64.Uint64 = (UINT64)MemAddr;
> diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.inf b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.inf
> index 82d5f7a..8921dd5 100644
> --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.inf
> +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.inf
> @@ -70,6 +70,7 @@
>   
>   [Pcd]
>     gEfiMdeModulePkgTokenSpaceGuid.PcdAtaSmartEnable   ## SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdPrdtMaxDataLength
>   
>   # [Event]
>   # EVENT_TYPE_PERIODIC_TIMER ## SOMETIMES_CONSUMES
> diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
> index 8efad57..b2f9f2b 100644
> --- a/MdeModulePkg/MdeModulePkg.dec
> +++ b/MdeModulePkg/MdeModulePkg.dec
> @@ -1434,6 +1434,9 @@
>     # @Prompt Console Output Row of Text Setup
>     gEfiMdeModulePkgTokenSpaceGuid.PcdSetupConOutRow|25|UINT32|0x4000000e
>   
> +  ## This PCD specifies the Maximum data length for a PRD Entry
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdPrdtMaxDataLength|0x3FFFFF|UINT32|0x4000000f
> +
>   [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
>     ## UART clock frequency is for the baud rate configuration.
>     # @Prompt Serial Port Clock Rate.
> 


-- 
Thanks,
Ray