Merge branch 'pci/iommu'

- Allow PASID on fake PCIe devices, e.g., HiSilicon KunPeng920 and
  KunPeng930 AMBA devices, without TLP prefixes (Zhangfei Gao)

- Allow SVA / dma-can-stall on fake PCIe devices (Zhangfei Gao)

* pci/iommu:
  PCI: Set dma-can-stall for HiSilicon chips
  PCI: Allow PASID on fake PCIe devices without TLP prefixes

2 files changed, 40 insertions, 1 deletions

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 6d7d64939f82..c967ad6e2626 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -376,7 +376,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
 	if (WARN_ON(pdev->pasid_enabled))
 		return -EBUSY;
 
-	if (!pdev->eetlp_prefix_path)
+	if (!pdev->eetlp_prefix_path && !pdev->pasid_no_tlp)
 		return -EINVAL;
 
 	if (!pasid)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 664233c2ef29..0b5eace979fc 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1822,6 +1822,45 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_E7525_MCH,	quir
 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_HUAWEI, 0x1610, PCI_CLASS_BRIDGE_PCI, 8, quirk_pcie_mch);
 
 /*
+ * HiSilicon KunPeng920 and KunPeng930 have devices appear as PCI but are
+ * actually on the AMBA bus. These fake PCI devices can support SVA via
+ * SMMU stall feature, by setting dma-can-stall for ACPI platforms.
+ *
+ * Normally stalling must not be enabled for PCI devices, since it would
+ * break the PCI requirement for free-flowing writes and may lead to
+ * deadlock.  We expect PCI devices to support ATS and PRI if they want to
+ * be fault-tolerant, so there's no ACPI binding to describe anything else,
+ * even when a "PCI" device turns out to be a regular old SoC device
+ * dressed up as a RCiEP and normal rules don't apply.
+ */
+static void quirk_huawei_pcie_sva(struct pci_dev *pdev)
+{
+	struct property_entry properties[] = {
+		PROPERTY_ENTRY_BOOL("dma-can-stall"),
+		{},
+	};
+
+	if (pdev->revision != 0x21 && pdev->revision != 0x30)
+		return;
+
+	pdev->pasid_no_tlp = 1;
+
+	/*
+	 * Set the dma-can-stall property on ACPI platforms. Device tree
+	 * can set it directly.
+	 */
+	if (!pdev->dev.of_node &&
+	    device_add_properties(&pdev->dev, properties))
+		pci_warn(pdev, "could not add stall property");
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa250, quirk_huawei_pcie_sva);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa251, quirk_huawei_pcie_sva);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa255, quirk_huawei_pcie_sva);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa256, quirk_huawei_pcie_sva);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa258, quirk_huawei_pcie_sva);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa259, quirk_huawei_pcie_sva);
+
+/*
  * It's possible for the MSI to get corrupted if SHPC and ACPI are used
  * together on certain PXH-based systems.
  */