powerpc/numa: NUMA topology support for PowerNV

This patch adds support for numa topology on powernv platforms running
OPAL formware. It checks for the type of platform at run time and
sets the affinity form correctly so that NUMA topology can be discovered
correctly.
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/mm/numa.c

@@ -315,6 +315,9 @@ static int __init find_min_common_depth(void)
 	struct device_node *root;
 	const char *vec5;
 
+	if (firmware_has_feature(FW_FEATURE_OPAL))
+		root = of_find_node_by_path("/ibm,opal");
+	else
 		root = of_find_node_by_path("/rtas");
 	if (!root)
 		root = of_find_node_by_path("/");
@@ -344,14 +347,21 @@ static int __init find_min_common_depth(void)
 
 #define VEC5_AFFINITY_BYTE	5
 #define VEC5_AFFINITY		0x80
+
+	if (firmware_has_feature(FW_FEATURE_OPAL))
+		form1_affinity = 1;
+	else {
 		chosen = of_find_node_by_path("/chosen");
 		if (chosen) {
-		vec5 = of_get_property(chosen, "ibm,architecture-vec-5", NULL);
-		if (vec5 && (vec5[VEC5_AFFINITY_BYTE] & VEC5_AFFINITY)) {
+			vec5 = of_get_property(chosen,
+					       "ibm,architecture-vec-5", NULL);
+			if (vec5 && (vec5[VEC5_AFFINITY_BYTE] &
+							VEC5_AFFINITY)) {
 				dbg("Using form 1 affinity\n");
 				form1_affinity = 1;
 			}
 		}
+	}
 
 	if (form1_affinity) {
 		depth = distance_ref_points[0];