dm: core: Provide a way to reset the device tree

At present there is only one device tree used by the ofnode functions,
except for some esoteric use of live tree. In preparation for supporting
more than one, add a way to reset the list of device trees.

For now this does nothing.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/board_r.c

@@ -234,6 +234,8 @@ static int initr_dm(void)
 {
 	int ret;
 
+	oftree_reset();
+
 	/* Save the pre-reloc driver model and start a new one */
 	gd->dm_root_f = gd->dm_root;
 	gd->dm_root = NULL;

include/dm/ofnode.h

@@ -27,6 +27,14 @@ struct ofnode_phandle_args {
 	uint32_t args[OF_MAX_PHANDLE_ARGS];
 };
 
+/**
+ * oftree_reset() - reset the state of the oftree list
+ *
+ * Reset the oftree list so it can be started again. This should be called
+ * once the control FDT is in place, but before the ofnode interface is used.
+ */
+static inline void oftree_reset(void) {}
+
 /**
  * ofnode_to_np() - convert an ofnode to a live DT node pointer
  *

lib/fdtdec.c

@@ -13,7 +13,6 @@
 #include <log.h>
 #include <malloc.h>
 #include <net.h>
-#include <dm/of_extra.h>
 #include <env.h>
 #include <errno.h>
 #include <fdtdec.h>
@@ -24,6 +23,8 @@
 #include <serial.h>
 #include <asm/global_data.h>
 #include <asm/sections.h>
+#include <dm/ofnode.h>
+#include <dm/of_extra.h>
 #include <linux/ctype.h>
 #include <linux/lzo.h>
 #include <linux/ioport.h>
@@ -1668,6 +1669,8 @@ int fdtdec_setup(void)
 	ret = fdtdec_prepare_fdt();
 	if (!ret)
 		ret = fdtdec_board_setup(gd->fdt_blob);
+	oftree_reset();
+
 	return ret;
 }
 

test/test-main.c

@@ -11,6 +11,7 @@
 #include <event.h>
 #include <of_live.h>
 #include <os.h>
+#include <dm/ofnode.h>
 #include <dm/root.h>
 #include <dm/test.h>
 #include <dm/uclass-internal.h>
@@ -99,6 +100,7 @@ static int dm_test_pre_run(struct unit_test_state *uts)
 
 	/* Determine whether to make the live tree available */
 	gd_set_of_root(of_live ? uts->of_root : NULL);
+	oftree_reset();
 	ut_assertok(dm_init(of_live));
 	uts->root = dm_root();