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path: root/drivers/pci/probe.c
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Diffstat (limited to 'drivers/pci/probe.c')
-rw-r--r--drivers/pci/probe.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c31310db0404..e6a917b4acd3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1762,6 +1762,48 @@ static void pci_configure_extended_tags(struct pci_dev *dev)
PCI_EXP_DEVCTL_EXT_TAG);
}
+/**
+ * pcie_relaxed_ordering_enabled - Probe for PCIe relaxed ordering enable
+ * @dev: PCI device to query
+ *
+ * Returns true if the device has enabled relaxed ordering attribute.
+ */
+bool pcie_relaxed_ordering_enabled(struct pci_dev *dev)
+{
+ u16 v;
+
+ pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &v);
+
+ return !!(v & PCI_EXP_DEVCTL_RELAX_EN);
+}
+EXPORT_SYMBOL(pcie_relaxed_ordering_enabled);
+
+static void pci_configure_relaxed_ordering(struct pci_dev *dev)
+{
+ struct pci_dev *root;
+
+ /* PCI_EXP_DEVICE_RELAX_EN is RsvdP in VFs */
+ if (dev->is_virtfn)
+ return;
+
+ if (!pcie_relaxed_ordering_enabled(dev))
+ return;
+
+ /*
+ * For now, we only deal with Relaxed Ordering issues with Root
+ * Ports. Peer-to-Peer DMA is another can of worms.
+ */
+ root = pci_find_pcie_root_port(dev);
+ if (!root)
+ return;
+
+ if (root->dev_flags & PCI_DEV_FLAGS_NO_RELAXED_ORDERING) {
+ pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
+ PCI_EXP_DEVCTL_RELAX_EN);
+ dev_info(&dev->dev, "Disable Relaxed Ordering because the Root Port didn't support it\n");
+ }
+}
+
static void pci_configure_device(struct pci_dev *dev)
{
struct hotplug_params hpp;
@@ -1769,6 +1811,7 @@ static void pci_configure_device(struct pci_dev *dev)
pci_configure_mps(dev);
pci_configure_extended_tags(dev);
+ pci_configure_relaxed_ordering(dev);
memset(&hpp, 0, sizeof(hpp));
ret = pci_get_hp_params(dev, &hpp);