dm: core: parse chosen node

This is the node that would contain, for example, the framebuffer setup
by an earlier stage.

Signed-off-by: Rob Clark <robdclark@gmail.com>

arch/sandbox/dts/test.dts

@@ -478,6 +478,13 @@
 	wdt0: wdt@0 {
 		compatible = "sandbox,wdt";
 	};
+
+	chosen {
+		chosen-test {
+			compatible = "denx,u-boot-fdt-test";
+			reg = <9 1>;
+		};
+	};
 };
 
 #include "sandbox_pmic.dtsi"

drivers/core/root.c

@@ -266,6 +266,17 @@ static int dm_scan_fdt_node(struct udevice *parent, const void *blob,
 	for (offset = fdt_first_subnode(blob, offset);
 	     offset > 0;
 	     offset = fdt_next_subnode(blob, offset)) {
+		/* "chosen" node isn't a device itself but may contain some: */
+		if (!strcmp(fdt_get_name(blob, offset, NULL), "chosen")) {
+			pr_debug("parsing subnodes of \"chosen\"\n");
+
+			err = dm_scan_fdt_node(parent, blob, offset,
+					       pre_reloc_only);
+			if (err && !ret)
+				ret = err;
+			continue;
+		}
+
 		if (pre_reloc_only &&
 		    !dm_fdt_pre_reloc(blob, offset))
 			continue;

test/dm/bus.c

@@ -105,7 +105,7 @@ UCLASS_DRIVER(testbus) = {
 /* Test that we can probe for children */
 static int dm_test_bus_children(struct unit_test_state *uts)
 {
-	int num_devices = 6;
+	int num_devices = 7;
 	struct udevice *bus;
 	struct uclass *uc;
 

test/dm/test-fdt.c

@@ -167,7 +167,7 @@ int dm_check_devices(struct unit_test_state *uts, int num_devices)
 /* Test that FDT-based binding works correctly */
 static int dm_test_fdt(struct unit_test_state *uts)
 {
-	const int num_devices = 6;
+	const int num_devices = 7;
 	struct udevice *dev;
 	struct uclass *uc;
 	int ret;