diff options
Diffstat (limited to 'drivers/pci/quirks.c')
| -rw-r--r-- | drivers/pci/quirks.c | 57 |
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 |