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. Best regards, David
