Patch "iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to identity" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iommu-arm-smmu-v3-make-default-domain-type-of-hisili.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5fbf8f705f3c00af4d5629920c9416c8b6c26f83
Author: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
Date:   Tue Aug 16 19:44:10 2022 +0800

    iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to identity
    
    [ Upstream commit 24b6c7798a0122012ca848ea0d25e973334266b0 ]
    
    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@xxxxxxxxxx>
    Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
    Reviewed-by: John Garry <john.garry@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220816114414.4092-2-yangyicong@xxxxxxxxxx
    Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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 79edfdca6607..e7da4a47ce52 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2832,6 +2832,26 @@ 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,
@@ -2857,6 +2877,7 @@ 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,
 };