On 9 October 2017 at 08:42, Ni, Ruiyu <[email protected]> wrote:
> The "read"/"write" is from the Bus Master's point of view.
>
>
> Thanks/Ray
>
>> -----Original Message-----
>> From: edk2-devel [mailto:[email protected]] On Behalf Of Daniil
>> Egranov
>> Sent: Monday, October 9, 2017 9:16 AM
>> To: [email protected]
>> Cc: [email protected]; Zeng, Star <[email protected]>;
>> [email protected]
>> Subject: [edk2] [PATCH] MdeModulePkg/PciHostBridgeDxe: Fixed PCI DMA
>> Map/Umap bounce buffer
>>
>> The patch corrects the logic of transferring data between a bounce buffer
>> and a
>> real buffer above 4GB:
>> 1. In the case of mapping a bounce buffer for the write operation, data from
>> a
>> real buffer should be copied into a bounce buffer.
>> 2.In the case of unmapping a bounce buffer for the read operation, data
>> should
>> be copied from a bounce buffer into a real buffer.
>>
>> The patch resolves a Juno board issue with the the grub and SATA drives.
>>
I am intrigued by this.
So as I suggested, this has to do with 64-bit DMA, but not in the way
I suspected. UEFI itself never hits this code path, because it runs
entirely < 32 GB, but as soon as GRUB starts allocating loader data
and use it for DMA, the bounce buffering kicks in because apparently,
the SATA controller is not 64-bit DMA capable.
Are you using the SataSiI3132Dxe driver on Juno? Does this help at all?
diff --git a/EmbeddedPkg/Drivers/SataSiI3132Dxe/SiI3132AtaPassThru.c
b/EmbeddedPkg/Drivers/SataSiI3132Dxe/SiI3132AtaPassThru.c
index 2fb5fd68db01..a938563ebdd6 100644
--- a/EmbeddedPkg/Drivers/SataSiI3132Dxe/SiI3132AtaPassThru.c
+++ b/EmbeddedPkg/Drivers/SataSiI3132Dxe/SiI3132AtaPassThru.c
@@ -104,7 +104,7 @@ SiI3132AtaPassThruCommand (
}
Status = PciIo->Map (
- PciIo, EfiPciIoOperationBusMasterRead,
+ PciIo, EfiPciIoOperationBusMasterWrite,
Packet->InDataBuffer, &InDataBufferLength,
&PhysInDataBuffer, &PciAllocMapping
);
if (EFI_ERROR (Status)) {
@@ -139,7 +139,7 @@ SiI3132AtaPassThruCommand (
OutDataBufferLength = Packet->OutTransferLength * SataDevice->BlockSize;
Status = PciIo->Map (
- PciIo, EfiPciIoOperationBusMasterWrite,
+ PciIo, EfiPciIoOperationBusMasterRead,
Packet->OutDataBuffer, &OutDataBufferLength,
&PhysOutDataBuffer, &PciAllocMapping
);
if (EFI_ERROR (Status)) {
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