Il giorno sab 5 ott 2019 alle ore 06:56 Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> ha scritto: > > On Tue 01 Oct 15:01 PDT 2019, kholk11@xxxxxxxxx wrote: > > > From: AngeloGioacchino Del Regno <kholk11@xxxxxxxxx> > > > > Some Qualcomm Family-B SoCs have got a different version of the QCOM > > IOMMU, specifically v2 and 500, which perfectly adhere to the current > > qcom_iommu driver, but need some variations due to slightly different > > hypervisor behavior. > > > > Do you think it's out of the question to get the arm-smmu driver to play > nice with this platform? > > > If not, would it be possible to change the DT binding so that we specify > the SID and then read the SMR and S2CR registers to figure out the > associated context bank? > > Regards, > Bjorn > > > The personal aim is to upstream MSM8956 as much as possible. > > > > This code has been tested on two Sony phones featuring the Qualcomm > > MSM8956 SoC. > > > > Changes in v2: > > - Fixed optional properties placement in documentation > > > > Changes in v3: > > - Rebased onto linux-next 01/10/2019 > > - Added missing SCM commit (required by the AArch64 PT switch support) > > > > Changes in v4: > > - Removed rej files from the SCM patch (I'm truly sorry for the noise...) > > > > Angelo G. Del Regno (1): > > firmware: qcom: scm: Add function to set IOMMU pagetable addressing > > > > AngeloGioacchino Del Regno (6): > > iommu/qcom: Use the asid read from device-tree if specified > > iommu/qcom: Write TCR before TTBRs to fix ASID access behavior > > iommu/qcom: Properly reset the IOMMU context > > iommu/qcom: Add support for AArch64 IOMMU pagetables > > iommu/qcom: Index contexts by asid number to allow asid 0 > > iommu/qcom: Add support for QCIOMMUv2 and QCIOMMU-500 secured contexts > > > > .../devicetree/bindings/iommu/qcom,iommu.txt | 5 + > > drivers/firmware/qcom_scm-32.c | 6 + > > drivers/firmware/qcom_scm-64.c | 15 ++ > > drivers/firmware/qcom_scm.c | 7 + > > drivers/firmware/qcom_scm.h | 4 + > > drivers/iommu/qcom_iommu.c | 134 ++++++++++++++---- > > include/linux/qcom_scm.h | 2 + > > 7 files changed, 145 insertions(+), 28 deletions(-) > > > > -- > > 2.21.0 > > In reality, when I started the IOMMU integration for this SoC, the arm-smmu didn't even have the new arm-smmu-impl stuff.... I tried multiple times to get the arm-smmu driver to play nice with this IOMMU, but it's really too much work to do there, (even with the new arm-smmu-impl stuff) as we would have to make a lot of changes in that driver just to support this thing which, yes - it's standard-ish - but no, due to the firmware configuration that happens on this kind of platforms (the entire family, 8917, 8953, 8956, 8976 and others) there is a lil percent of the arm-smmu code that would apply. Shorter said, since it would be a complete mess to integrate the support there, IMHO it's really not a good idea. In my trials for that I've ended up changing like 50% of the arm-smmu driver. After all, the qcom_iommu driver is there to get IOMMUs with this kind of firmware configuration working and, even if it was originally done for QCIOMMUv1, as I have also explained in one of the patches here, 98-99% of the reasons why we have a separate driver called qcom_iommu are applying to the implementation that I've done.
