The "read"/"write" is from the Bus Master's point of view.
Thanks/Ray > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of Daniil > Egranov > Sent: Monday, October 9, 2017 9:16 AM > To: edk2-devel@lists.01.org > Cc: leif.lindh...@linaro.org; Zeng, Star <star.z...@intel.com>; > ard.biesheu...@linaro.org > 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. > > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Daniil Egranov <daniil.egra...@arm.com> > --- > MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c > b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c > index dc06c16dc0..877fa2fd13 100644 > --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c > +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c > @@ -1153,12 +1153,12 @@ RootBridgeIoMap ( > } > > // > - // If this is a read operation from the Bus Master's point of view, > + // If this is a write operation from the Bus Master's point of > + view, > // then copy the contents of the real buffer into the mapped buffer > // so the Bus Master can read the contents of the real buffer. > // > - if (Operation == EfiPciOperationBusMasterRead || > - Operation == EfiPciOperationBusMasterRead64) { > + if (Operation == EfiPciOperationBusMasterWrite || > + Operation == EfiPciOperationBusMasterWrite64) { > CopyMem ( > (VOID *) (UINTN) MapInfo->MappedHostAddress, > (VOID *) (UINTN) MapInfo->HostAddress, @@ -1256,12 +1256,12 @@ > RootBridgeIoUnmap ( > RemoveEntryList (&MapInfo->Link); > > // > - // If this is a write operation from the Bus Master's point of view, > + // If this is a read operation from the Bus Master's point of view, > // then copy the contents of the mapped buffer into the real buffer > // so the processor can read the contents of the real buffer. > // > - if (MapInfo->Operation == EfiPciOperationBusMasterWrite || > - MapInfo->Operation == EfiPciOperationBusMasterWrite64) { > + if (MapInfo->Operation == EfiPciOperationBusMasterRead || > + MapInfo->Operation == EfiPciOperationBusMasterRead64) { > CopyMem ( > (VOID *) (UINTN) MapInfo->HostAddress, > (VOID *) (UINTN) MapInfo->MappedHostAddress, > -- > 2.11.0 > > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
