Hi Andreas, Could you provide us more information about the platform you are using? More specifically
1) Are you using any configs/example/arm based script? 2) Which bus is connected to the device DMA port? You need a cache between the device and the coherent bus. This is why we usually instantiate a IO cache between the iobus and the membus [1] Kind Regards Giacomo [1]: https://github.com/gem5/gem5/blob/stable/configs/example/arm/devices.py#L392 > -----Original Message----- > From: diavastos--- via gem5-users <gem5-users@gem5.org> > Sent: 13 September 2021 13:42 > To: gem5-users@gem5.org > Cc: diavas...@gmail.com > Subject: [gem5-users] Accelerator as PIO device writing back to main > memory > > Hi all, > > I implemented an accelerator as a PIO device in the latest version of gem5 > and I am having issues with accessing the main memory for write operations. > Reading from main memory works correctly. > > I used as an example an old entry "gem5-accel" that implements a Daxpy > accelerator (as far as I saw even more recent implementations use a similar > way to access main memory). My implementations for data transfer are > more or less the same as the example but writing back to main memory > doesn't work and I get the following runtime error: > > gem5.opt: build/ARM/mem/snoop_filter.cc:224: > std::pair<std::vector<QueuedResponsePort*>, Cycles> > SnoopFilter::lookupSnoop(const Packet*): Assertion `cpkt->isWriteback() || > cpkt->req->isUncacheable() || (cpkt->isInvalidate() == cpkt- > >needsWritable()) || cpkt->req->isCacheMaintenance()' failed. > > If I manually change the Packet type (just to avoid this error) to > MemCmd::WritebackDirty instead of the standard MemCmd::WriteReq, the > simulation continues with no error but the data are not actually written back > to main memory. > > Any ideas from anyone would be greatly appreciated! Or if there are other > examples I can follow to do the implementation > > Many thanks, > andreas > _______________________________________________ > gem5-users mailing list -- gem5-users@gem5.org To unsubscribe send an > email to gem5-users- > le...@gem5.org %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ gem5-users mailing list -- gem5-users@gem5.org To unsubscribe send an email to gem5-users-le...@gem5.org %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s
