diff options
| -rw-r--r-- | drivers/pci/pci.c | 24 | ||||
| -rw-r--r-- | drivers/pci/quirks.c | 57 | ||||
| -rw-r--r-- | include/linux/pci.h | 1 |
3 files changed, 82 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 6a9a1116f1eb..09b4a35e21a8 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -458,6 +458,30 @@ struct resource *pci_find_parent_resource(const struct pci_dev *dev, EXPORT_SYMBOL(pci_find_parent_resource); /** + * pci_find_pcie_root_port - return PCIe Root Port + * @dev: PCI device to query + * + * Traverse up the parent chain and return the PCIe Root Port PCI Device + * for a given PCI Device. + */ +struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) +{ + struct pci_dev *bridge, *highest_pcie_bridge = NULL; + + bridge = pci_upstream_bridge(dev); + while (bridge && pci_is_pcie(bridge)) { + highest_pcie_bridge = bridge; + bridge = pci_upstream_bridge(bridge); + } + + if (pci_pcie_type(highest_pcie_bridge) != PCI_EXP_TYPE_ROOT_PORT) + return NULL; + + return highest_pcie_bridge; +} +EXPORT_SYMBOL(pci_find_pcie_root_port); + +/** * pci_wait_for_pending - wait for @mask bit(s) to clear in status word @pos * @dev: the PCI device to operate on * @pos: config space offset of status word 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 diff --git a/include/linux/pci.h b/include/linux/pci.h index b54fbf1571b1..e828e7b4afec 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -820,6 +820,7 @@ void pci_bus_add_device(struct pci_dev *dev); void pci_read_bridge_bases(struct pci_bus *child); struct resource *pci_find_parent_resource(const struct pci_dev *dev, struct resource *res); +struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev); u8 pci_swizzle_interrupt_pin(const struct pci_dev *dev, u8 pin); int pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge); u8 pci_common_swizzle(struct pci_dev *dev, u8 *pinp); |
