Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

[safe/jmp/linux-2.6] / drivers / pci / search.c

diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index c6e79d0..b001b59 100644 (file)
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -14,6 +14,40 @@
 #include "pci.h"
 
 DECLARE_RWSEM(pci_bus_sem);
+/*
+ * find the upstream PCIE-to-PCI bridge of a PCI device
+ * if the device is PCIE, return NULL
+ * if the device isn't connected to a PCIE bridge (that is its parent is a
+ * legacy PCI bridge and the bridge is directly connected to bus 0), return its
+ * parent
+ */
+struct pci_dev *
+pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
+{
+       struct pci_dev *tmp = NULL;
+
+       if (pdev->is_pcie)
+               return NULL;
+       while (1) {
+               if (!pdev->bus->self)
+                       break;
+               pdev = pdev->bus->self;
+               /* a p2p bridge */
+               if (!pdev->is_pcie) {
+                       tmp = pdev;
+                       continue;
+               }
+               /* PCI device should connect to a PCIE bridge */
+               if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
+                       /* Busted hardware? */
+                       WARN_ON_ONCE(1);
+                       return NULL;
+               }
+               return pdev;
+       }
+
+       return tmp;
+}
 
 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 {