On Fri, 28 Feb 2020 13:56:46 +0000 Will Deacon <will@xxxxxxxxxx> wrote: > On Fri, Feb 28, 2020 at 01:42:54PM +0000, Andre Przywara wrote: > > On Fri, 28 Feb 2020 10:50:25 +0000 > > Will Deacon <will@xxxxxxxxxx> wrote: > > > On Fri, Feb 28, 2020 at 10:25:56AM +0000, Andre Przywara wrote: > > > > > On Tue, Feb 25, 2020 at 04:01:54PM -0600, Rob Herring wrote: > > > > > > Seems we're leaving the platform support for now, but I think we never > > > > > > actually enabled SMMU support. It's not in the dts either in mainline > > > > > > nor the version I have which should be close to what shipped in > > > > > > firmware. So as long as Andre agrees, this one is good to apply. > > > > > > > > > > Andre? Can I queue this one for 5.7, please? > > > > > > > > I was wondering how much of a pain it is to keep it in? AFAICS there are > > > > other users of the "impl" indirection. If those goes away, I would be > > > > happy to let Calxeda go. > > > > > > The impl stuff is new, so we'll keep it around. The concern is more about > > > testing (see below). > > > > > > > But Eric had the magic DT nodes to get the SMMU working, and I used that > > > > before, with updating the DT either on flash or dynamically via U-Boot. > > > > > > What did you actually use the SMMU for, though? The > > > 'arm_iommu_create_mapping()' interface isn't widely used and, given that > > > highbank doesn't support KVM, the use-cases for VFIO are pretty limited > > > too. > > > > AFAIK Highbank doesn't have the SMMU, probably mostly for that reason. > > I have a DT snippet for Midway, and that puts the MMIO base at ~36GB, which is not possible on Highbank. > > So I think that the quirk is really meant and needed for Midway. > > Sorry, but I don't follow your reasoning here. The MMIO base has nothing > to do with the quirk, It hasn't, but Highbank has no LPAE, so couldn't possible have a device at such an address. And this is the only MMIO address I know of. > although doing some digging it looks like your > conclusion about this applying to Midway (ecx-2000?) is correct: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-January/226095.html Right, thanks for that find. Yes, Midway is the codename for the ECX-2000 SoC product. Cheers, Andre > > > > So I don't know exactly *how* desperate you are with removing this, or if > > > > there are other reasons than "negative diffstat", but if possible I would > > > > like to keep it in. > > > > > > It's more that we *do* make quite a lot of changes to the arm-smmu driver > > > and it's never tested with this quirk. If you're stepping up to run smmu > > > tests on my queue for each release on highbank, then great, but otherwise > > > I'd rather not carry the code for fun. The change in diffstat is minimal > > > (we're going to need to hooks for nvidia, who broke things in a different > > > way). > > > > I am about to set up some more sophisticated testing, and will include > > some SMMU bits in it. > > Yes, please. > > Will
