On Sun, 3 Jul 2022 at 13:47, David Virag <virag.david003@xxxxxxxxx> wrote: > > On Sun, 2022-07-03 at 00:48 +0300, Sam Protsenko wrote: > [...] > > Hi Marek, > > > > As I understand, you have some board with SysMMU v7, which is not VM > > capable (judging from the patches you shared earlier). Could you > > please somehow verify if this series works fine for you? For example, > > this testing driver [1] can be helpful. > > > > Thanks! > > > > [1] > > https://github.com/joe-skb7/linux/commit/bbadd46fa525fe1fef2ccbdfff81f7d29caf0506 > > Hi Sam, > > Not Marek here, but I wanted to try this on my jackpotlte (Exynos > 7885). The driver reports it's DPU sysmmu as version 7.2, and manually > reading the capabilities registers it looks like it has the 2nd > capability register but not the VM capability. > > After applying your patches, adding your test driver (with SYSMMU_BASE > corrected to 7885 value), and adding the sysmmu to dt, I tried to cat > the test file that it creates in debugfs and I got an SError kernel > panic. > > I tried tracing where the SError happens and it looks like it's this > line: > /* Preload for emulation */ > iowrite32(rw | vpn, obj->reg_base + MMU_EMU_PRELOAD); > > Trying to read the EMU registers using devmem results in a "Bus error". > > Could these emulation registers be missing from my SysMMU? Do you have > any info on what version should have it? Or maybe some capability bit? > I'll try testing it with DECON/DPP later and see if it works that way. > Hey David, Can you please try out the [1] branch again? I've added support for Exynos7885 there, using the info provided by Janghyuck Kim: apparently Exynos7885 has EMU registers, but those have some other offsets than on Exynos850: #define MMU_EMU_PRELOAD 0x8040 #define MMU_EMU_SHOT 0x8044 I wonder if my changes to [1] do the trick. [1] https://github.com/joe-skb7/linux/tree/e850-96-mainline-iommu > Best regards, > David
