PCI: Set dma-can-stall for HiSilicon chips

[linux-2.6-microblaze.git] / drivers / pci / quirks.c

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 5d46ac6..1871c1d 100644 (file)
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1821,12 +1821,37 @@ 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);