dm: add DM_FLAG_BOUND flag

Currently, we only have DM_FLAG_ACTIVATED to indicate the device
status, but we still cannot know in which stage is in progress,
binding or probing.

This commit introduces a new flag, DM_FLAG_BOUND, which is set when
the device is really bound, and cleared when it is unbound.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/core/device-remove.c

@@ -61,6 +61,9 @@ int device_unbind(struct udevice *dev)
 	if (dev->flags & DM_FLAG_ACTIVATED)
 		return -EINVAL;
 
+	if (!(dev->flags & DM_FLAG_BOUND))
+		return -EINVAL;
+
 	drv = dev->driver;
 	assert(drv);
 

drivers/core/device.c

@@ -132,6 +132,8 @@ int device_bind(struct udevice *parent, const struct driver *drv,
 		dm_dbg("Bound device %s to %s\n", dev->name, parent->name);
 	*devp = dev;
 
+	dev->flags |= DM_FLAG_BOUND;
+
 	return 0;
 
 fail_child_post_bind:

include/dm/device.h

@@ -36,6 +36,9 @@ struct driver_info;
 /* Allocate driver private data on a DMA boundary */
 #define DM_FLAG_ALLOC_PRIV_DMA	(1 << 5)
 
+/* Device is bound */
+#define DM_FLAG_BOUND	(1 << 6)
+
 /**
  * struct udevice - An instance of a driver
  *