Hi Magnus, <snip..> >> Magnus, do you have a suggestion? > > Thanks for your efforts guys! > > I've recently been working on up-porting the IPMMU patches and > addressing review comments. Now with my local driver stack on top of > v4.12-rc (a95cfad) I did not notice these issues initially since I > only tested devices with IPMMU enabled. Once these issues were pointed > out to me by Geert I have now reproduced the 64-bit ARM specific ones > on r8a7796 Salvator-X. > > On my r8a7796 platform I'm using the following IOMMU and DMA Engine devices: > > IOMMU device IPMMU-DS0 - Connected to SYS-DMAC0 > IOMMU device IPMMU-DS1 - Connected to SYS-DMAC1 and SYS-DMAC2 > IOMMU device IPMMU-MM - Root device serving IPMMU-DS0 and IPMMU-DS1 > > For testing the serial port SCIF1 is used with DMA Engine devices > SYS-DMAC1 or SYS-DMAC2. > > The software environment is configured as follows: > - The DTS comes with all devices above enabled except IPMMU-DS0 which > comes with status = "disabled". > - The IPMMU driver is during run time only allowing use of SYS-DMAC2. > For other devices ->of_xlate() returns -ENODEV. > > The above used to work just fine with v4.11 or earlier. > > My observations for v4.12-rc: > > 1) Default state for a95cfad > > The devices SYS-DMAC0 and SYS-DMAC1 will never probe. However SYS-DMAC2 is fine. > > 2) After applying "[PATCH] iommu: of: Fix check for returning EPROBE_DEFER" [1] > > This fixes SYS-DMAC0 that now probes and operates without IPMMU-DS0 as > expected. Same as v4.11 or earlier. > > 3) After also applying "[PATCH] of: iommu: Ignore all errors except > EPROBE_DEFER" [2] > > This fixes SYS-DMAC1 that now probes and operates without IPMMU-DS1 as > expected. Same as v4.11 or earlier. > > With fix [1] and [2] things seem back to normal. Unless I'm mistaken Thanks, will use this as your Tested-by. Regards, Sricharan > it also seems that [1] allows me to drop the similar patch "[PATCH/RFC > v2 1/4] iommu/of: Skip IOMMU devices disabled in DT". > > Thanks for your help. > > Cheers, > > / magnus > > > [1] https://lkml.org/lkml/2017/5/16/25 > [2] https://www.spinics.net/lists/arm-kernel/msg581485.html > [3] https://patchwork.kernel.org/patch/9540605/ > -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
