dm: core: Allow getting some basic stats

Add a function that returns some basic stats about driver model. For now
we only have two.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/device.c b/drivers/core/device.c
index 74374ff..4873c47 100644
--- a/drivers/core/device.c
+++ b/drivers/core/device.c
@@ -739,6 +739,17 @@
 	return count;
 }
 
+int device_get_decendent_count(const struct udevice *parent)
+{
+	const struct udevice *dev;
+	int count = 1;
+
+	list_for_each_entry(dev, &parent->child_head, sibling_node)
+		count += device_get_decendent_count(dev);
+
+	return count;
+}
+
 int device_find_child_by_seq(const struct udevice *parent, int seq,
 			     struct udevice **devp)
 {
diff --git a/drivers/core/root.c b/drivers/core/root.c
index 26b8195..815173f 100644
--- a/drivers/core/root.c
+++ b/drivers/core/root.c
@@ -26,6 +26,7 @@
 #include <dm/read.h>
 #include <dm/root.h>
 #include <dm/uclass.h>
+#include <dm/uclass-internal.h>
 #include <dm/util.h>
 #include <linux/list.h>
 
@@ -407,6 +408,12 @@
 	return 0;
 }
 
+void dm_get_stats(int *device_countp, int *uclass_countp)
+{
+	*device_countp = device_get_decendent_count(gd->dm_root);
+	*uclass_countp = uclass_get_count();
+}
+
 #ifdef CONFIG_ACPIGEN
 static int root_acpi_get_name(const struct udevice *dev, char *out_name)
 {
diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
index 2aa2143..336ea8d 100644
--- a/drivers/core/uclass.c
+++ b/drivers/core/uclass.c
@@ -643,6 +643,19 @@
 	return device_probe(*devp);
 }
 
+int uclass_get_count(void)
+{
+	const struct uclass *uc;
+	int count = 0;
+
+	if (gd->dm_root) {
+		list_for_each_entry(uc, gd->uclass_root, sibling_node)
+			count++;
+	}
+
+	return count;
+}
+
 int uclass_first_device_drvdata(enum uclass_id id, ulong driver_data,
 				struct udevice **devp)
 {