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path: root/drivers/pci/quirks.c
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Diffstat (limited to 'drivers/pci/quirks.c')
-rw-r--r--drivers/pci/quirks.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 6a30252cd79f..eb3c98e0fb2b 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3692,6 +3692,63 @@ DECLARE_PCI_FIXUP_CLASS_EARLY(0x1797, 0x6869, PCI_CLASS_NOT_DEFINED, 8,
quirk_tw686x_class);
/*
+ * Per PCIe r3.0, sec 2.2.9, "Completion headers must supply the same
+ * values for the Attribute as were supplied in the header of the
+ * corresponding Request, except as explicitly allowed when IDO is used."
+ *
+ * If a non-compliant device generates a completion with a different
+ * attribute than the request, the receiver may accept it (which itself
+ * seems non-compliant based on sec 2.3.2), or it may handle it as a
+ * Malformed TLP or an Unexpected Completion, which will probably lead to a
+ * device access timeout.
+ *
+ * If the non-compliant device generates completions with zero attributes
+ * (instead of copying the attributes from the request), we can work around
+ * this by disabling the "Relaxed Ordering" and "No Snoop" attributes in
+ * upstream devices so they always generate requests with zero attributes.
+ *
+ * This affects other devices under the same Root Port, but since these
+ * attributes are performance hints, there should be no functional problem.
+ *
+ * Note that Configuration Space accesses are never supposed to have TLP
+ * Attributes, so we're safe waiting till after any Configuration Space
+ * accesses to do the Root Port fixup.
+ */
+static void quirk_disable_root_port_attributes(struct pci_dev *pdev)
+{
+ struct pci_dev *root_port = pci_find_pcie_root_port(pdev);
+
+ if (!root_port) {
+ dev_warn(&pdev->dev, "PCIe Completion erratum may cause device errors\n");
+ return;
+ }
+
+ dev_info(&root_port->dev, "Disabling No Snoop/Relaxed Ordering Attributes to avoid PCIe Completion erratum in %s\n",
+ dev_name(&pdev->dev));
+ pcie_capability_clear_and_set_word(root_port, PCI_EXP_DEVCTL,
+ PCI_EXP_DEVCTL_RELAX_EN |
+ PCI_EXP_DEVCTL_NOSNOOP_EN, 0);
+}
+
+/*
+ * The Chelsio T5 chip fails to copy TLP Attributes from a Request to the
+ * Completion it generates.
+ */
+static void quirk_chelsio_T5_disable_root_port_attributes(struct pci_dev *pdev)
+{
+ /*
+ * This mask/compare operation selects for Physical Function 4 on a
+ * T5. We only need to fix up the Root Port once for any of the
+ * PFs. PF[0..3] have PCI Device IDs of 0x50xx, but PF4 is uniquely
+ * 0x54xx so we use that one,
+ */
+ if ((pdev->device & 0xff00) == 0x5400)
+ quirk_disable_root_port_attributes(pdev);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
+ quirk_chelsio_T5_disable_root_port_attributes);
+
+/*
* AMD has indicated that the devices below do not support peer-to-peer
* in any system where they are found in the southbridge with an AMD
* IOMMU in the system. Multifunction devices that do not support