dm: core: Add a way to collect memory usage

Add a function for collecting the amount of memory used by driver model,
including devices, uclasses and attached data and tags.

This information can provide insights into how to reduce the memory
required by driver model. Future work may look at execution speed also.

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

drivers/core/root.c

@@ -449,6 +449,59 @@ void dm_get_stats(int *device_countp, int *uclass_countp)
 	*uclass_countp = uclass_get_count();
 }
 
+void dev_collect_stats(struct dm_stats *stats, const struct udevice *parent)
+{
+	const struct udevice *dev;
+	int i;
+
+	stats->dev_count++;
+	stats->dev_size += sizeof(struct udevice);
+	stats->dev_name_size += strlen(parent->name) + 1;
+	for (i = 0; i < DM_TAG_ATTACH_COUNT; i++) {
+		int size = dev_get_attach_size(parent, i);
+
+		if (size ||
+		    (i == DM_TAG_DRIVER_DATA && parent->driver_data)) {
+			stats->attach_count[i]++;
+			stats->attach_size[i] += size;
+			stats->attach_count_total++;
+			stats->attach_size_total += size;
+		}
+	}
+
+	list_for_each_entry(dev, &parent->child_head, sibling_node)
+		dev_collect_stats(stats, dev);
+}
+
+void uclass_collect_stats(struct dm_stats *stats)
+{
+	struct uclass *uc;
+
+	list_for_each_entry(uc, gd->uclass_root, sibling_node) {
+		int size;
+
+		stats->uc_count++;
+		stats->uc_size += sizeof(struct uclass);
+		size = uc->uc_drv->priv_auto;
+		if (size) {
+			stats->uc_attach_count++;
+			stats->uc_attach_size += size;
+		}
+	}
+}
+
+void dm_get_mem(struct dm_stats *stats)
+{
+	memset(stats, '\0', sizeof(*stats));
+	dev_collect_stats(stats, gd->dm_root);
+	uclass_collect_stats(stats);
+	dev_tag_collect_stats(stats);
+
+	stats->total_size = stats->dev_size + stats->uc_size +
+		stats->attach_size_total + stats->uc_attach_size +
+		stats->tag_size;
+}
+
 #ifdef CONFIG_ACPIGEN
 static int root_acpi_get_name(const struct udevice *dev, char *out_name)
 {