powerpc/eeh: Fix PE location code

In eeh_pe_loc_get(), the PE location code is retrieved from the
"ibm,loc-code" property of the device node for the bridge of the
PE's primary bus. It's not correct because the property indicates
the parent PE's location code.

This reads the correct PE location code from "ibm,io-base-loc-code"
or "ibm,slot-location-code" property of PE parent bus's device node.

Cc: stable@vger.kernel.org # v3.16+
Fixes: 357b2f3dd9b7 ("powerpc/eeh: Dump PE location code")
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/eeh_pe.c

@@ -883,32 +883,29 @@ void eeh_pe_restore_bars(struct eeh_pe *pe)
 const char *eeh_pe_loc_get(struct eeh_pe *pe)
 {
 	struct pci_bus *bus = eeh_pe_bus_get(pe);
-	struct device_node *dn = pci_bus_to_OF_node(bus);
+	struct device_node *dn;
 	const char *loc = NULL;
 
-	if (!dn)
-		goto out;
+	while (bus) {
+		dn = pci_bus_to_OF_node(bus);
+		if (!dn) {
+			bus = bus->parent;
+			continue;
+		}
 
-	/* PHB PE or root PE ? */
-	if (pci_is_root_bus(bus)) {
-		loc = of_get_property(dn, "ibm,loc-code", NULL);
-		if (!loc)
+		if (pci_is_root_bus(bus))
 			loc = of_get_property(dn, "ibm,io-base-loc-code", NULL);
+		else
+			loc = of_get_property(dn, "ibm,slot-location-code",
+					      NULL);
+
 		if (loc)
-			goto out;
+			return loc;
 
-		/* Check the root port */
-		dn = dn->child;
-		if (!dn)
-			goto out;
+		bus = bus->parent;
 	}
 
-	loc = of_get_property(dn, "ibm,loc-code", NULL);
-	if (!loc)
-		loc = of_get_property(dn, "ibm,slot-location-code", NULL);
-
-out:
-	return loc ? loc : "N/A";
+	return "N/A";
 }
 
 /**