On 9 October 2017 at 11:40, Ard Biesheuvel <[email protected]> wrote: > 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)) {
Also, it might make sense to find out if the hardware is really not 64-bit DMA capable, or whether the driver simply fails to set the EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE attribute. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
