[PATCH] Enabling OF selftest to run without machine's devicetree

@@ -366,6 +366,9 @@ void of_fdt_unflatten_tree(unsigned long *blob,
 			struct device_node **mynodes)
 {
 	__unflatten_device_tree(blob, mynodes, &kernel_tree_alloc);
+
+	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
+	of_alias_scan(&kernel_tree_alloc);
 }
 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 

@@ -16,6 +16,7 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <linux/proc_fs.h>
 
 static struct selftest_results {
 	int passed;

@@ -25,6 +26,7 @@ static struct selftest_results {
 #define NO_OF_NODES 2
 static struct device_node *nodes[NO_OF_NODES];
 static int last_node_index;
+static bool selftest_live_tree;
 
 #define selftest(result, fmt, ...) { \
 	if (!(result)) { \

@@ -595,7 +597,7 @@ static int attach_node_and_children(struct device_node *np)
 static int __init selftest_data_add(void)
 {
 	void *selftest_data;
-	struct device_node *selftest_data_node;
+	struct device_node *selftest_data_node, *np;
 	extern uint8_t __dtb_testcases_begin[];
 	extern uint8_t __dtb_testcases_end[];
 	const int size = __dtb_testcases_end - __dtb_testcases_begin;

@@ -614,10 +616,31 @@ static int __init selftest_data_add(void)
 			"not running tests\n", __func__);
 		return -ENOMEM;
 	}
-	of_fdt_unflatten_tree(selftest_data, &selftest_data_node);
 
-	/* attach the sub-tree to live tree */
-	return attach_node_and_children(selftest_data_node);
+	if (!of_allnodes) {
+		/* enabling flag for removing nodes */
+		selftest_live_tree = true;
+
+		of_fdt_unflatten_tree(selftest_data, &of_allnodes);
+		if (!of_allnodes) {
+			pr_warn("%s: No tree to attach; not running tests\n",
+				__func__);
+			return -ENODATA;
+		}
+
+		for_each_of_allnodes(np)
+			of_node_add(np);
+
+		/* Symlink in /proc as required by userspace ABI */
+		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
+
+		return 0;
+	} else {
+		of_fdt_unflatten_tree(selftest_data, &selftest_data_node);
+
+		/* attach the sub-tree to live tree */
+		return attach_node_and_children(selftest_data_node);
+	}
 }
 
 /**

@@ -646,6 +669,9 @@ static void selftest_data_remove(void)
 	struct device_node *np;
 	struct property *prop;
 
+	if (selftest_live_tree)
+		return detach_node_and_children(of_allnodes);
+
 	while (last_node_index >= 0) {
 		if (nodes[last_node_index]) {
 			np = of_find_node_by_path(nodes[last_node_index]->full_name);