PCI: Add support for PCIe-to-PCI bridge DMA alias quirks

Several PCIe-to-PCI bridges fail to provide a PCIe capability, causing us
to handle them as conventional PCI devices when they really use the
requester ID of the secondary bus.  We need to differentiate these from
PCIe-to-PCI bridges that actually use the conventional PCI ID when a PCIe
capability is not present, such as those found on the root complex of may
Intel chipsets.  Add a dev_flag bit to identify devices to be handled as
standard PCIe-to-PCI bridges.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index 2c19f3f40621..df38f73f091f 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -88,8 +88,14 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
                                 continue;
                         }
                 } else {
-                        ret = fn(tmp, PCI_DEVID(tmp->bus->number, tmp->devfn),
-                                 data);
+                        if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
+                                ret = fn(tmp,
+                                         PCI_DEVID(tmp->subordinate->number,
+                                                   PCI_DEVFN(0, 0)), data);
+                        else
+                                ret = fn(tmp,
+                                         PCI_DEVID(tmp->bus->number,
+                                                   tmp->devfn), data);
                         if (ret)
                                 return ret;
                 }