of: Transactional DT support.

Introducing DT transactional support.

A DT transaction is a method which allows one to apply changes
in the live tree, in such a way that either the full set of changes
take effect, or the state of the tree can be rolled-back to the
state it was before it was attempted. An applied transaction
can be rolled-back at any time.

Documentation is in
	Documentation/devicetree/changesets.txt

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[glikely: Removed device notifiers and reworked to be more consistent]
Signed-off-by: Grant Likely <grant.likely@linaro.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/include/linux/of.h b/include/linux/of.h
index 400f18cb4fff..bc91fbb13ce8 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -786,4 +786,80 @@ typedef void (*of_init_fn_1)(struct device_node *);
 #define OF_DECLARE_2(table, name, compat, fn) \
                 _OF_DECLARE(table, name, compat, fn, of_init_fn_2)
 
+/**
+ * struct of_changeset_entry    - Holds a changeset entry
+ *
+ * @node:       list_head for the log list
+ * @action:     notifier action
+ * @np:         pointer to the device node affected
+ * @prop:       pointer to the property affected
+ * @old_prop:   hold a pointer to the original property
+ *
+ * Every modification of the device tree during a changeset
+ * is held in a list of of_changeset_entry structures.
+ * That way we can recover from a partial application, or we can
+ * revert the changeset
+ */
+struct of_changeset_entry {
+        struct list_head node;
+        unsigned long action;
+        struct device_node *np;
+        struct property *prop;
+        struct property *old_prop;
+};
+
+/**
+ * struct of_changeset - changeset tracker structure
+ *
+ * @entries:    list_head for the changeset entries
+ *
+ * changesets are a convenient way to apply bulk changes to the
+ * live tree. In case of an error, changes are rolled-back.
+ * changesets live on after initial application, and if not
+ * destroyed after use, they can be reverted in one single call.
+ */
+struct of_changeset {
+        struct list_head entries;
+};
+
+#ifdef CONFIG_OF_DYNAMIC
+extern void of_changeset_init(struct of_changeset *ocs);
+extern void of_changeset_destroy(struct of_changeset *ocs);
+extern int of_changeset_apply(struct of_changeset *ocs);
+extern int of_changeset_revert(struct of_changeset *ocs);
+extern int of_changeset_action(struct of_changeset *ocs,
+                unsigned long action, struct device_node *np,
+                struct property *prop);
+
+static inline int of_changeset_attach_node(struct of_changeset *ocs,
+                struct device_node *np)
+{
+        return of_changeset_action(ocs, OF_RECONFIG_ATTACH_NODE, np, NULL);
+}
+
+static inline int of_changeset_detach_node(struct of_changeset *ocs,
+                struct device_node *np)
+{
+        return of_changeset_action(ocs, OF_RECONFIG_DETACH_NODE, np, NULL);
+}
+
+static inline int of_changeset_add_property(struct of_changeset *ocs,
+                struct device_node *np, struct property *prop)
+{
+        return of_changeset_action(ocs, OF_RECONFIG_ADD_PROPERTY, np, prop);
+}
+
+static inline int of_changeset_remove_property(struct of_changeset *ocs,
+                struct device_node *np, struct property *prop)
+{
+        return of_changeset_action(ocs, OF_RECONFIG_REMOVE_PROPERTY, np, prop);
+}
+
+static inline int of_changeset_update_property(struct of_changeset *ocs,
+                struct device_node *np, struct property *prop)
+{
+        return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
+}
+#endif
+
 #endif /* _LINUX_OF_H */