MIPS: PCI: Prevent hang on XLP reg read

Reading PCI extended register at 0x255 on a bridge will hang if there
is no device connected on the link. Make PCI read routine skip this
register.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: http://patchwork.linux-mips.org/patch/4789/
Signed-off-by: John Crispin <blogic@openwrt.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/mips/pci/pci-xlp.c b/arch/mips/pci/pci-xlp.c
index 5077148bd67d..fbf001a068a4 100644
--- a/arch/mips/pci/pci-xlp.c
+++ b/arch/mips/pci/pci-xlp.c
@@ -64,8 +64,12 @@ static inline u32 pci_cfg_read_32bit(struct pci_bus *bus, unsigned int devfn,
         u32 data;
         u32 *cfgaddr;
 
+        where &= ~3;
+        if (bus->number == 0 && PCI_SLOT(devfn) == 1 && where == 0x954)
+                return 0xffffffff;
+
         cfgaddr = (u32 *)(pci_config_base +
-                        pci_cfg_addr(bus->number, devfn, where & ~3));
+                        pci_cfg_addr(bus->number, devfn, where));
         data = *cfgaddr;
         return data;
 }