Bjorn Helgaas created a patch for making PCI_SCAN_ALL_PCIE_DEVS work for 
Root Ports as well as Downstream. Previously PCI_SCAN_ALL_PCIE_DEVS (set 
by quirks or the "pci=pcie_scan_all"
kernel parameter) only affected Switch Downstream Ports, not Root Ports. 
The problem is, that we have to add always the boot argument 
"pci=pcie_scan_all" for using Bjorn's improvements. Without the boot 
argument "pci=pcie_scan_all", the kernel doesn't boot on P.A. Semi 
boards with SB600 chipset (SB600 chipset is connected via PCIe x4 to the 
P.A. Semi’s PA6T-1682M System-on-a-Chip) because the kernel can't find 
any drives connected to the SB600 anymore. Olof Johansson has created a 
patch for executing "pci=pcie_scan_all" automatically on P.A. Semi 
boards. With his patch, we don't need to add 'pci=pcie_scan_all' to the 
kernel boot arguments anymore.

---

arch/powerpc/platforms/pasemi/pci.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/platforms/pasemi/pci.c 

b/arch/powerpc/platforms/pasemi/pci.c
index 5ff6108..ea54ed2 100644

--- a/arch/powerpc/platforms/pasemi/pci.c
+++ b/arch/powerpc/platforms/pasemi/pci.c

@@ -224,6 +224,8 @@ void __init pas_pci_init(void)
          return;
      }

+    pci_set_flags(PCI_SCAN_ALL_PCIE_DEVS);
+
      for (np = NULL; (np = of_get_next_child(root, np)) != NULL;)
          if (np->name && !strcmp(np->name, "pxp") && !pas_add_bridge(np))
              of_node_get(np);

--