powerpc/eeh: Dump PE location code

As Ben suggested, it's meaningful to dump PE's location code
for site engineers when hitting EEH errors. The patch introduces
function eeh_pe_loc_get() to retireve the location code from
dev-tree so that we can output it when hitting EEH errors.

If primary PE bus is root bus, the PHB's dev-node would be tried
prior to root port's dev-node. Otherwise, the upstream bridge's
dev-node of the primary PE bus will be check for the location code
directly.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index b76f58c..fab7743 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -254,6 +254,7 @@
 void *eeh_pe_dev_traverse(struct eeh_pe *root,
 		eeh_traverse_func fn, void *flag);
 void eeh_pe_restore_bars(struct eeh_pe *pe);
+const char *eeh_pe_loc_get(struct eeh_pe *pe);
 struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe);
 
 void *eeh_dev_init(struct device_node *dn, void *data);