dm: core: Add safe device iteration macros

Add iteration macros which support unbinding a device within the loop.

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

include/dm/device.h

@@ -509,6 +509,18 @@ static inline bool device_is_on_pci_bus(struct udevice *dev)
 	return device_get_uclass_id(dev->parent) == UCLASS_PCI;
 }
 
+/**
+ * device_foreach_child_safe() - iterate through child devices safely
+ *
+ * This allows the @pos child to be removed in the loop if required.
+ *
+ * @pos: struct udevice * for the current device
+ * @next: struct udevice * for the next device
+ * @parent: parent device to scan
+ */
+#define device_foreach_child_safe(pos, next, parent)	\
+	list_for_each_entry_safe(pos, next, &parent->child_head, sibling_node)
+
 /* device resource management */
 typedef void (*dr_release_t)(struct udevice *dev, void *res);
 typedef int (*dr_match_t)(struct udevice *dev, void *res, void *match_data);

include/dm/uclass.h

@@ -243,4 +243,19 @@ int uclass_resolve_seq(struct udevice *dev);
 #define uclass_foreach_dev(pos, uc)	\
 	list_for_each_entry(pos, &uc->dev_head, uclass_node)
 
+/**
+ * uclass_foreach_dev_safe() - Helper function to safely iteration through devs
+ *
+ * This creates a for() loop which works through the available devices in
+ * a uclass in order from start to end. Inside the loop, it is safe to remove
+ * @pos if required.
+ *
+ * @pos: struct udevice * to hold the current device. Set to NULL when there
+ * are no more devices.
+ * @next: struct udevice * to hold the next next
+ * @uc: uclass to scan
+ */
+#define uclass_foreach_dev_safe(pos, next, uc)	\
+	list_for_each_entry_safe(pos, next, &uc->dev_head, uclass_node)
+
 #endif