On Thu, Apr 07, 2022 at 08:58:35PM +0800, Yicong Yang wrote: > The DMA operations of HiSilicon PTT device can only work properly with > identical mappings. So add a quirk for the device to force the domain > as passthrough. > > Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx> > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) I still don't like this being part of the SMMU driver, but given that (a) Robin doesn't seem to agree with the objection and (b) you've been refreshing the patch series: Acked-by: Will Deacon <will@xxxxxxxxxx> If you do respin, then: > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > index 627a3ed5ee8f..5ec15ae2a9b1 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -2839,6 +2839,21 @@ static int arm_smmu_dev_disable_feature(struct device *dev, > } > } It might be worth adding a brief comment here to explain what this device is and why it needs an identity mapping. > +#define IS_HISI_PTT_DEVICE(pdev) ((pdev)->vendor == PCI_VENDOR_ID_HUAWEI && \ > + (pdev)->device == 0xa12e) Will
