On Thu, Mar 25, 2021 at 12:02:56PM -0500, Bjorn Andersson wrote: > On Thu 25 Mar 09:59 CDT 2021, Will Deacon wrote: > > > [+ Lorenzo] > > > > On Mon, Mar 01, 2021 at 03:40:21PM +0800, Shawn Guo wrote: > > > Though qcom_adreno_smmu_impl is not used by ACPI boot right now, > > > qcom_smmu_impl is already required at least to boot up Lenovo Flex 5G > > > laptop. Let's check asl_compiler_id in IORT header to ensure we are > > > running a QCOM SMMU and create qcom_smmu_impl for it. > > > > > > !np is used to check ACPI boot, because fwnode of SMMU device is > > > a static allocation and thus has_acpi_companion() doesn't work here. > > > > > > Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx> > > > --- > > > drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 33 ++++++++++++++++++++++ > > > 1 file changed, 33 insertions(+) > > > > I don't know what a "asl_compiler_id" is, but it doesn't sound like it > > has an awful lot to do with the SMMU. > > > > I would prefer that we somehow relate this to the particular board, > rather than all Qualcomm-related ACPI tables. E.g. by relying on the > SMMU devices having a _HID of QCOM0409. > > Shawn, any reason for this wouldn't be possible? > > > Lorenzo -- any idea what we should be doing here instead? Probably not > > using ACPI? > > > > The 8cx (aka sc8180x) platform comes with Qualcomm's usual SMMU > stream-mapping quirks and this is one of the patches needed to bring > enough ACPI support to run the Debian installer that Shawn has been > working on. After the installer we currently only boot this using DT - > which already enables the quirk. I am not sure I follow - can you explain please why this patch (and so the QCOM SMMU) is actually needed ? I don't get why getting the SMMU up and running with ACPI is mandatory to complete the process you describe above (but I am not sure I understood it entirely either - apologies). Thanks, Lorenzo
