iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to identity

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.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20220816114414.4092-2-yangyicong@huawei.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

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 d32b023..71f7edd 100644 (file)
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2817,6 +2817,26 @@ static int arm_smmu_dev_disable_feature(struct device *dev,
        }
 }
 
+/*
+ * HiSilicon PCIe tune and trace device can be used to trace TLP headers on the
+ * PCIe link and save the data to memory by DMA. The hardware is restricted to
+ * use identity mapping only.
+ */
+#define IS_HISI_PTT_DEVICE(pdev)       ((pdev)->vendor == PCI_VENDOR_ID_HUAWEI && \
+                                        (pdev)->device == 0xa12e)
+
+static int arm_smmu_def_domain_type(struct device *dev)
+{
+       if (dev_is_pci(dev)) {
+               struct pci_dev *pdev = to_pci_dev(dev);
+
+               if (IS_HISI_PTT_DEVICE(pdev))
+                       return IOMMU_DOMAIN_IDENTITY;
+       }
+
+       return 0;
+}
+
 static struct iommu_ops arm_smmu_ops = {
        .capable                = arm_smmu_capable,
        .domain_alloc           = arm_smmu_domain_alloc,
@@ -2831,6 +2851,7 @@ static struct iommu_ops arm_smmu_ops = {
        .sva_unbind             = arm_smmu_sva_unbind,
        .sva_get_pasid          = arm_smmu_sva_get_pasid,
        .page_response          = arm_smmu_page_response,
+       .def_domain_type        = arm_smmu_def_domain_type,
        .pgsize_bitmap          = -1UL, /* Restricted during device attach */
        .owner                  = THIS_MODULE,
        .default_domain_ops = &(const struct iommu_domain_ops) {