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>
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 7bd5501..c1002b7 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -314,3 +314,347 @@
kfree(node);
return NULL;
}
+
+static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
+{
+ of_node_put(ce->np);
+ list_del(&ce->node);
+ kfree(ce);
+}
+
+#ifdef DEBUG
+static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
+{
+ switch (ce->action) {
+ case OF_RECONFIG_ADD_PROPERTY:
+ pr_debug("%p: %s %s/%s\n",
+ ce, "ADD_PROPERTY ", ce->np->full_name,
+ ce->prop->name);
+ break;
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ pr_debug("%p: %s %s/%s\n",
+ ce, "REMOVE_PROPERTY", ce->np->full_name,
+ ce->prop->name);
+ break;
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ pr_debug("%p: %s %s/%s\n",
+ ce, "UPDATE_PROPERTY", ce->np->full_name,
+ ce->prop->name);
+ break;
+ case OF_RECONFIG_ATTACH_NODE:
+ pr_debug("%p: %s %s\n",
+ ce, "ATTACH_NODE ", ce->np->full_name);
+ break;
+ case OF_RECONFIG_DETACH_NODE:
+ pr_debug("%p: %s %s\n",
+ ce, "DETACH_NODE ", ce->np->full_name);
+ break;
+ }
+}
+#else
+static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
+{
+ /* empty */
+}
+#endif
+
+static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
+ struct of_changeset_entry *rce)
+{
+ memcpy(rce, ce, sizeof(*rce));
+
+ switch (ce->action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ rce->action = OF_RECONFIG_DETACH_NODE;
+ break;
+ case OF_RECONFIG_DETACH_NODE:
+ rce->action = OF_RECONFIG_ATTACH_NODE;
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ rce->action = OF_RECONFIG_REMOVE_PROPERTY;
+ break;
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ rce->action = OF_RECONFIG_ADD_PROPERTY;
+ break;
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ rce->old_prop = ce->prop;
+ rce->prop = ce->old_prop;
+ break;
+ }
+}
+
+static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
+{
+ struct of_changeset_entry ce_inverted;
+ int ret;
+
+ if (revert) {
+ __of_changeset_entry_invert(ce, &ce_inverted);
+ ce = &ce_inverted;
+ }
+
+ switch (ce->action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ case OF_RECONFIG_DETACH_NODE:
+ ret = of_reconfig_notify(ce->action, ce->np);
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
+ break;
+ default:
+ pr_err("%s: invalid devicetree changeset action: %i\n", __func__,
+ (int)ce->action);
+ return;
+ }
+
+ if (ret)
+ pr_err("%s: notifier error @%s\n", __func__, ce->np->full_name);
+}
+
+static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
+{
+ struct property *old_prop, **propp;
+ unsigned long flags;
+ int ret = 0;
+
+ __of_changeset_entry_dump(ce);
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ switch (ce->action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ __of_attach_node(ce->np);
+ break;
+ case OF_RECONFIG_DETACH_NODE:
+ __of_detach_node(ce->np);
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ /* If the property is in deadprops then it must be removed */
+ for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
+ if (*propp == ce->prop) {
+ *propp = ce->prop->next;
+ ce->prop->next = NULL;
+ break;
+ }
+ }
+
+ ret = __of_add_property(ce->np, ce->prop);
+ if (ret) {
+ pr_err("%s: add_property failed @%s/%s\n",
+ __func__, ce->np->full_name,
+ ce->prop->name);
+ break;
+ }
+ break;
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ ret = __of_remove_property(ce->np, ce->prop);
+ if (ret) {
+ pr_err("%s: remove_property failed @%s/%s\n",
+ __func__, ce->np->full_name,
+ ce->prop->name);
+ break;
+ }
+ break;
+
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ /* If the property is in deadprops then it must be removed */
+ for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
+ if (*propp == ce->prop) {
+ *propp = ce->prop->next;
+ ce->prop->next = NULL;
+ break;
+ }
+ }
+
+ ret = __of_update_property(ce->np, ce->prop, &old_prop);
+ if (ret) {
+ pr_err("%s: update_property failed @%s/%s\n",
+ __func__, ce->np->full_name,
+ ce->prop->name);
+ break;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ if (ret)
+ return ret;
+
+ switch (ce->action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ __of_attach_node_sysfs(ce->np);
+ break;
+ case OF_RECONFIG_DETACH_NODE:
+ __of_detach_node_sysfs(ce->np);
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ /* ignore duplicate names */
+ __of_add_property_sysfs(ce->np, ce->prop);
+ break;
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ __of_remove_property_sysfs(ce->np, ce->prop);
+ break;
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
+ break;
+ }
+
+ return 0;
+}
+
+static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
+{
+ struct of_changeset_entry ce_inverted;
+
+ __of_changeset_entry_invert(ce, &ce_inverted);
+ return __of_changeset_entry_apply(&ce_inverted);
+}
+
+/**
+ * of_changeset_init - Initialize a changeset for use
+ *
+ * @ocs: changeset pointer
+ *
+ * Initialize a changeset structure
+ */
+void of_changeset_init(struct of_changeset *ocs)
+{
+ memset(ocs, 0, sizeof(*ocs));
+ INIT_LIST_HEAD(&ocs->entries);
+}
+
+/**
+ * of_changeset_destroy - Destroy a changeset
+ *
+ * @ocs: changeset pointer
+ *
+ * Destroys a changeset. Note that if a changeset is applied,
+ * its changes to the tree cannot be reverted.
+ */
+void of_changeset_destroy(struct of_changeset *ocs)
+{
+ struct of_changeset_entry *ce, *cen;
+
+ list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
+ __of_changeset_entry_destroy(ce);
+}
+
+/**
+ * of_changeset_apply - Applies a changeset
+ *
+ * @ocs: changeset pointer
+ *
+ * Applies a changeset to the live tree.
+ * Any side-effects of live tree state changes are applied here on
+ * sucess, like creation/destruction of devices and side-effects
+ * like creation of sysfs properties and directories.
+ * Returns 0 on success, a negative error value in case of an error.
+ * On error the partially applied effects are reverted.
+ */
+int of_changeset_apply(struct of_changeset *ocs)
+{
+ struct of_changeset_entry *ce;
+ int ret;
+
+ /* perform the rest of the work */
+ pr_debug("of_changeset: applying...\n");
+ list_for_each_entry(ce, &ocs->entries, node) {
+ ret = __of_changeset_entry_apply(ce);
+ if (ret) {
+ pr_err("%s: Error applying changeset (%d)\n", __func__, ret);
+ list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
+ __of_changeset_entry_revert(ce);
+ return ret;
+ }
+ }
+ pr_debug("of_changeset: applied, emitting notifiers.\n");
+
+ /* drop the global lock while emitting notifiers */
+ mutex_unlock(&of_mutex);
+ list_for_each_entry(ce, &ocs->entries, node)
+ __of_changeset_entry_notify(ce, 0);
+ mutex_lock(&of_mutex);
+ pr_debug("of_changeset: notifiers sent.\n");
+
+ return 0;
+}
+
+/**
+ * of_changeset_revert - Reverts an applied changeset
+ *
+ * @ocs: changeset pointer
+ *
+ * Reverts a changeset returning the state of the tree to what it
+ * was before the application.
+ * Any side-effects like creation/destruction of devices and
+ * removal of sysfs properties and directories are applied.
+ * Returns 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_revert(struct of_changeset *ocs)
+{
+ struct of_changeset_entry *ce;
+ int ret;
+
+ pr_debug("of_changeset: reverting...\n");
+ list_for_each_entry_reverse(ce, &ocs->entries, node) {
+ ret = __of_changeset_entry_revert(ce);
+ if (ret) {
+ pr_err("%s: Error reverting changeset (%d)\n", __func__, ret);
+ list_for_each_entry_continue(ce, &ocs->entries, node)
+ __of_changeset_entry_apply(ce);
+ return ret;
+ }
+ }
+ pr_debug("of_changeset: reverted, emitting notifiers.\n");
+
+ /* drop the global lock while emitting notifiers */
+ mutex_unlock(&of_mutex);
+ list_for_each_entry_reverse(ce, &ocs->entries, node)
+ __of_changeset_entry_notify(ce, 1);
+ mutex_lock(&of_mutex);
+ pr_debug("of_changeset: notifiers sent.\n");
+
+ return 0;
+}
+
+/**
+ * of_changeset_action - Perform a changeset action
+ *
+ * @ocs: changeset pointer
+ * @action: action to perform
+ * @np: Pointer to device node
+ * @prop: Pointer to property
+ *
+ * On action being one of:
+ * + OF_RECONFIG_ATTACH_NODE
+ * + OF_RECONFIG_DETACH_NODE,
+ * + OF_RECONFIG_ADD_PROPERTY
+ * + OF_RECONFIG_REMOVE_PROPERTY,
+ * + OF_RECONFIG_UPDATE_PROPERTY
+ * Returns 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_action(struct of_changeset *ocs, unsigned long action,
+ struct device_node *np, struct property *prop)
+{
+ struct of_changeset_entry *ce;
+
+ ce = kzalloc(sizeof(*ce), GFP_KERNEL);
+ if (!ce) {
+ pr_err("%s: Failed to allocate\n", __func__);
+ return -ENOMEM;
+ }
+ /* get a reference to the node */
+ ce->action = action;
+ ce->np = of_node_get(np);
+ ce->prop = prop;
+
+ if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
+ ce->old_prop = of_find_property(np, prop->name, NULL);
+
+ /* add it to the list */
+ list_add_tail(&ce->node, &ocs->entries);
+ return 0;
+}