dm: core: Allow device names to be freed automatically

Some devices have a name that is stored in allocated memory. At present
there is no mechanism to free this memory when the device is unbound.

Add a device flag to track whether a name is allocated and a function to
add the flag. Free the memory when the device is unbound.

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

drivers/core/device-remove.c

@@ -112,6 +112,8 @@ int device_unbind(struct udevice *dev)
 
 	devres_release_all(dev);
 
+	if (dev->flags & DM_NAME_ALLOCED)
+		free((char *)dev->name);
 	free(dev);
 
 	return 0;

drivers/core/device.c

@@ -706,12 +706,18 @@ bool device_is_last_sibling(struct udevice *dev)
 	return list_is_last(&dev->sibling_node, &parent->child_head);
 }
 
+void device_set_name_alloced(struct udevice *dev)
+{
+	dev->flags |= DM_NAME_ALLOCED;
+}
+
 int device_set_name(struct udevice *dev, const char *name)
 {
 	name = strdup(name);
 	if (!name)
 		return -ENOMEM;
 	dev->name = name;
+	device_set_name_alloced(dev);
 
 	return 0;
 }

include/dm/device.h

@@ -41,6 +41,9 @@ struct driver_info;
 /* Device is bound */
 #define DM_FLAG_BOUND			(1 << 6)
 
+/* Device name is allocated and should be freed on unbind() */
+#define DM_NAME_ALLOCED			(1 << 7)
+
 /**
  * struct udevice - An instance of a driver
  *
@@ -523,6 +526,9 @@ bool device_is_last_sibling(struct udevice *dev);
  * this is unnecessary but for probed devices which don't get a useful name
  * this function can be helpful.
  *
+ * The name is allocated and will be freed automatically when the device is
+ * unbound.
+ *
  * @dev:	Device to update
  * @name:	New name (this string is allocated new memory and attached to
  *		the device)
@@ -531,6 +537,16 @@ bool device_is_last_sibling(struct udevice *dev);
  */
 int device_set_name(struct udevice *dev, const char *name);
 
+/**
+ * device_set_name_alloced() - note that a device name is allocated
+ *
+ * This sets the DM_NAME_ALLOCED flag for the device, so that when it is
+ * unbound the name will be freed. This avoids memory leaks.
+ *
+ * @dev:	Device to update
+ */
+void device_set_name_alloced(struct udevice *dev);
+
 /**
  * device_is_on_pci_bus - Test if a device is on a PCI bus
  *