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.aggar...@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
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