On Wed, 19 Jun 2019 at 12:09, Ooi, Tzy Way <tzy.way....@intel.com> wrote: > > Hi Bieshuevel, > > In the DmaMap function, there is one line where my code look like this: > > "Status = DmaMap (MapOperationBusMasterCommonBuffer, > Snp->MacDriver.TxdescRing[0], &BufferSize, &Snp->MacDriver.TxdescRingMap[0], > &Snp->MappingTxdesc);" > > You asked me why the [0] and how many descriptor I am mapping. In my code, > there is total 10 descriptors. The way I did in current code was I use > DmaAllocateBuffer to allocate a memory size which is big enough for 10 > descriptors. After that, I just map the first descriptor and I access the > rest of the descriptor by using the first descriptor address plus the size > for each descriptor to get the next descriptor address. Wonder if this method > is ok? Or do I need to use DmaAllocateBuffer and DmaMap for 10 times for > total 10 descriptors? >
No, this is not ok. You have to allocate and map the size of the memory that you will use. As long as you don't use more than a page, it will not matter in practice, but it is wrong nonetheless -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#42589): https://edk2.groups.io/g/devel/message/42589 Mute This Topic: https://groups.io/mt/31541649/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
