On 2022/5/10 19:23, Will Deacon wrote: > 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 add a brief comment here in next version. Thanks, Yicong
