v4.19.13 snapshot.
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
new file mode 100644
index 0000000..f4f8ed9
--- /dev/null
+++ b/drivers/of/dynamic.c
@@ -0,0 +1,894 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support for dynamic device trees.
+ *
+ * On some platforms, the device tree can be manipulated at runtime.
+ * The routines in this section support adding, removing and changing
+ * device tree nodes.
+ */
+
+#define pr_fmt(fmt) "OF: " fmt
+
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/proc_fs.h>
+
+#include "of_private.h"
+
+static struct device_node *kobj_to_device_node(struct kobject *kobj)
+{
+ return container_of(kobj, struct device_node, kobj);
+}
+
+/**
+ * of_node_get() - Increment refcount of a node
+ * @node: Node to inc refcount, NULL is supported to simplify writing of
+ * callers
+ *
+ * Returns node.
+ */
+struct device_node *of_node_get(struct device_node *node)
+{
+ if (node)
+ kobject_get(&node->kobj);
+ return node;
+}
+EXPORT_SYMBOL(of_node_get);
+
+/**
+ * of_node_put() - Decrement refcount of a node
+ * @node: Node to dec refcount, NULL is supported to simplify writing of
+ * callers
+ */
+void of_node_put(struct device_node *node)
+{
+ if (node)
+ kobject_put(&node->kobj);
+}
+EXPORT_SYMBOL(of_node_put);
+
+static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
+
+int of_reconfig_notifier_register(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&of_reconfig_chain, nb);
+}
+EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
+
+int of_reconfig_notifier_unregister(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
+}
+EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
+
+#ifdef DEBUG
+const char *action_names[] = {
+ [OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
+ [OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
+ [OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
+ [OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
+ [OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
+};
+#endif
+
+int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
+{
+ int rc;
+#ifdef DEBUG
+ struct of_reconfig_data *pr = p;
+
+ switch (action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ case OF_RECONFIG_DETACH_NODE:
+ pr_debug("notify %-15s %pOF\n", action_names[action],
+ pr->dn);
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ pr_debug("notify %-15s %pOF:%s\n", action_names[action],
+ pr->dn, pr->prop->name);
+ break;
+
+ }
+#endif
+ rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
+ return notifier_to_errno(rc);
+}
+
+/*
+ * of_reconfig_get_state_change() - Returns new state of device
+ * @action - action of the of notifier
+ * @arg - argument of the of notifier
+ *
+ * Returns the new state of a device based on the notifier used.
+ * Returns 0 on device going from enabled to disabled, 1 on device
+ * going from disabled to enabled and -1 on no change.
+ */
+int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
+{
+ struct property *prop, *old_prop = NULL;
+ int is_status, status_state, old_status_state, prev_state, new_state;
+
+ /* figure out if a device should be created or destroyed */
+ switch (action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ case OF_RECONFIG_DETACH_NODE:
+ prop = of_find_property(pr->dn, "status", NULL);
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ prop = pr->prop;
+ break;
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ prop = pr->prop;
+ old_prop = pr->old_prop;
+ break;
+ default:
+ return OF_RECONFIG_NO_CHANGE;
+ }
+
+ is_status = 0;
+ status_state = -1;
+ old_status_state = -1;
+ prev_state = -1;
+ new_state = -1;
+
+ if (prop && !strcmp(prop->name, "status")) {
+ is_status = 1;
+ status_state = !strcmp(prop->value, "okay") ||
+ !strcmp(prop->value, "ok");
+ if (old_prop)
+ old_status_state = !strcmp(old_prop->value, "okay") ||
+ !strcmp(old_prop->value, "ok");
+ }
+
+ switch (action) {
+ case OF_RECONFIG_ATTACH_NODE:
+ prev_state = 0;
+ /* -1 & 0 status either missing or okay */
+ new_state = status_state != 0;
+ break;
+ case OF_RECONFIG_DETACH_NODE:
+ /* -1 & 0 status either missing or okay */
+ prev_state = status_state != 0;
+ new_state = 0;
+ break;
+ case OF_RECONFIG_ADD_PROPERTY:
+ if (is_status) {
+ /* no status property -> enabled (legacy) */
+ prev_state = 1;
+ new_state = status_state;
+ }
+ break;
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ if (is_status) {
+ prev_state = status_state;
+ /* no status property -> enabled (legacy) */
+ new_state = 1;
+ }
+ break;
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ if (is_status) {
+ prev_state = old_status_state != 0;
+ new_state = status_state != 0;
+ }
+ break;
+ }
+
+ if (prev_state == new_state)
+ return OF_RECONFIG_NO_CHANGE;
+
+ return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
+}
+EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
+
+int of_property_notify(int action, struct device_node *np,
+ struct property *prop, struct property *oldprop)
+{
+ struct of_reconfig_data pr;
+
+ /* only call notifiers if the node is attached */
+ if (!of_node_is_attached(np))
+ return 0;
+
+ pr.dn = np;
+ pr.prop = prop;
+ pr.old_prop = oldprop;
+ return of_reconfig_notify(action, &pr);
+}
+
+static void __of_attach_node(struct device_node *np)
+{
+ const __be32 *phandle;
+ int sz;
+
+ np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
+ np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
+
+ phandle = __of_get_property(np, "phandle", &sz);
+ if (!phandle)
+ phandle = __of_get_property(np, "linux,phandle", &sz);
+ if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
+ phandle = __of_get_property(np, "ibm,phandle", &sz);
+ np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
+
+ np->child = NULL;
+ np->sibling = np->parent->child;
+ np->parent->child = np;
+ of_node_clear_flag(np, OF_DETACHED);
+}
+
+/**
+ * of_attach_node() - Plug a device node into the tree and global list.
+ */
+int of_attach_node(struct device_node *np)
+{
+ struct of_reconfig_data rd;
+ unsigned long flags;
+
+ memset(&rd, 0, sizeof(rd));
+ rd.dn = np;
+
+ mutex_lock(&of_mutex);
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ __of_attach_node(np);
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ __of_attach_node_sysfs(np);
+ mutex_unlock(&of_mutex);
+
+ of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
+
+ return 0;
+}
+
+void __of_detach_node(struct device_node *np)
+{
+ struct device_node *parent;
+
+ if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
+ return;
+
+ parent = np->parent;
+ if (WARN_ON(!parent))
+ return;
+
+ if (parent->child == np)
+ parent->child = np->sibling;
+ else {
+ struct device_node *prevsib;
+ for (prevsib = np->parent->child;
+ prevsib->sibling != np;
+ prevsib = prevsib->sibling)
+ ;
+ prevsib->sibling = np->sibling;
+ }
+
+ of_node_set_flag(np, OF_DETACHED);
+}
+
+/**
+ * of_detach_node() - "Unplug" a node from the device tree.
+ *
+ * The caller must hold a reference to the node. The memory associated with
+ * the node is not freed until its refcount goes to zero.
+ */
+int of_detach_node(struct device_node *np)
+{
+ struct of_reconfig_data rd;
+ unsigned long flags;
+ int rc = 0;
+
+ memset(&rd, 0, sizeof(rd));
+ rd.dn = np;
+
+ mutex_lock(&of_mutex);
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ __of_detach_node(np);
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ __of_detach_node_sysfs(np);
+ mutex_unlock(&of_mutex);
+
+ of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(of_detach_node);
+
+static void property_list_free(struct property *prop_list)
+{
+ struct property *prop, *next;
+
+ for (prop = prop_list; prop != NULL; prop = next) {
+ next = prop->next;
+ kfree(prop->name);
+ kfree(prop->value);
+ kfree(prop);
+ }
+}
+
+/**
+ * of_node_release() - release a dynamically allocated node
+ * @kref: kref element of the node to be released
+ *
+ * In of_node_put() this function is passed to kref_put() as the destructor.
+ */
+void of_node_release(struct kobject *kobj)
+{
+ struct device_node *node = kobj_to_device_node(kobj);
+
+ /* We should never be releasing nodes that haven't been detached. */
+ if (!of_node_check_flag(node, OF_DETACHED)) {
+ pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
+ dump_stack();
+ return;
+ }
+ if (!of_node_check_flag(node, OF_DYNAMIC))
+ return;
+
+ property_list_free(node->properties);
+ property_list_free(node->deadprops);
+
+ kfree(node->full_name);
+ kfree(node->data);
+ kfree(node);
+}
+
+/**
+ * __of_prop_dup - Copy a property dynamically.
+ * @prop: Property to copy
+ * @allocflags: Allocation flags (typically pass GFP_KERNEL)
+ *
+ * Copy a property by dynamically allocating the memory of both the
+ * property structure and the property name & contents. The property's
+ * flags have the OF_DYNAMIC bit set so that we can differentiate between
+ * dynamically allocated properties and not.
+ * Returns the newly allocated property or NULL on out of memory error.
+ */
+struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
+{
+ struct property *new;
+
+ new = kzalloc(sizeof(*new), allocflags);
+ if (!new)
+ return NULL;
+
+ /*
+ * NOTE: There is no check for zero length value.
+ * In case of a boolean property, this will allocate a value
+ * of zero bytes. We do this to work around the use
+ * of of_get_property() calls on boolean values.
+ */
+ new->name = kstrdup(prop->name, allocflags);
+ new->value = kmemdup(prop->value, prop->length, allocflags);
+ new->length = prop->length;
+ if (!new->name || !new->value)
+ goto err_free;
+
+ /* mark the property as dynamic */
+ of_property_set_flag(new, OF_DYNAMIC);
+
+ return new;
+
+ err_free:
+ kfree(new->name);
+ kfree(new->value);
+ kfree(new);
+ return NULL;
+}
+
+/**
+ * __of_node_dup() - Duplicate or create an empty device node dynamically.
+ * @np: if not NULL, contains properties to be duplicated in new node
+ * @full_name: string value to be duplicated into new node's full_name field
+ *
+ * Create a device tree node, optionally duplicating the properties of
+ * another node. The node data are dynamically allocated and all the node
+ * flags have the OF_DYNAMIC & OF_DETACHED bits set.
+ *
+ * Returns the newly allocated node or NULL on out of memory error.
+ */
+struct device_node *__of_node_dup(const struct device_node *np,
+ const char *full_name)
+{
+ struct device_node *node;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return NULL;
+ node->full_name = kstrdup(full_name, GFP_KERNEL);
+ if (!node->full_name) {
+ kfree(node);
+ return NULL;
+ }
+
+ of_node_set_flag(node, OF_DYNAMIC);
+ of_node_set_flag(node, OF_DETACHED);
+ of_node_init(node);
+
+ /* Iterate over and duplicate all properties */
+ if (np) {
+ struct property *pp, *new_pp;
+ for_each_property_of_node(np, pp) {
+ new_pp = __of_prop_dup(pp, GFP_KERNEL);
+ if (!new_pp)
+ goto err_prop;
+ if (__of_add_property(node, new_pp)) {
+ kfree(new_pp->name);
+ kfree(new_pp->value);
+ kfree(new_pp);
+ goto err_prop;
+ }
+ }
+ }
+ return node;
+
+ err_prop:
+ of_node_put(node); /* Frees the node and properties */
+ 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:
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
+ ce->np, ce->prop->name);
+ break;
+ case OF_RECONFIG_ATTACH_NODE:
+ case OF_RECONFIG_DETACH_NODE:
+ pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
+ ce->np);
+ 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;
+ /* update was used but original property did not exist */
+ if (!rce->prop) {
+ rce->action = OF_RECONFIG_REMOVE_PROPERTY;
+ rce->prop = ce->prop;
+ }
+ break;
+ }
+}
+
+static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
+ bool revert)
+{
+ struct of_reconfig_data rd;
+ struct of_changeset_entry ce_inverted;
+ int ret = 0;
+
+ 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:
+ memset(&rd, 0, sizeof(rd));
+ rd.dn = ce->np;
+ ret = of_reconfig_notify(ce->action, &rd);
+ 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("invalid devicetree changeset action: %i\n",
+ (int)ce->action);
+ ret = -EINVAL;
+ }
+
+ if (ret)
+ pr_err("changeset notifier error @%pOF\n", ce->np);
+ return ret;
+}
+
+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("changeset: add_property failed @%pOF/%s\n",
+ ce->np,
+ ce->prop->name);
+ break;
+ }
+ break;
+ case OF_RECONFIG_REMOVE_PROPERTY:
+ ret = __of_remove_property(ce->np, ce->prop);
+ if (ret) {
+ pr_err("changeset: remove_property failed @%pOF/%s\n",
+ ce->np,
+ 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("changeset: update_property failed @%pOF/%s\n",
+ ce->np,
+ 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);
+}
+EXPORT_SYMBOL_GPL(of_changeset_init);
+
+/**
+ * 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);
+}
+EXPORT_SYMBOL_GPL(of_changeset_destroy);
+
+/*
+ * Apply the changeset entries in @ocs.
+ * If apply fails, an attempt is made to revert the entries that were
+ * successfully applied.
+ *
+ * If multiple revert errors occur then only the final revert error is reported.
+ *
+ * Returns 0 on success, a negative error value in case of an error.
+ * If a revert error occurs, it is returned in *ret_revert.
+ */
+int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
+{
+ struct of_changeset_entry *ce;
+ int ret, ret_tmp;
+
+ pr_debug("changeset: applying...\n");
+ list_for_each_entry(ce, &ocs->entries, node) {
+ ret = __of_changeset_entry_apply(ce);
+ if (ret) {
+ pr_err("Error applying changeset (%d)\n", ret);
+ list_for_each_entry_continue_reverse(ce, &ocs->entries,
+ node) {
+ ret_tmp = __of_changeset_entry_revert(ce);
+ if (ret_tmp)
+ *ret_revert = ret_tmp;
+ }
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Returns 0 on success, a negative error value in case of an error.
+ *
+ * If multiple changeset entry notification errors occur then only the
+ * final notification error is reported.
+ */
+int __of_changeset_apply_notify(struct of_changeset *ocs)
+{
+ struct of_changeset_entry *ce;
+ int ret = 0, ret_tmp;
+
+ pr_debug("changeset: emitting notifiers.\n");
+
+ /* drop the global lock while emitting notifiers */
+ mutex_unlock(&of_mutex);
+ list_for_each_entry(ce, &ocs->entries, node) {
+ ret_tmp = __of_changeset_entry_notify(ce, 0);
+ if (ret_tmp)
+ ret = ret_tmp;
+ }
+ mutex_lock(&of_mutex);
+ pr_debug("changeset: notifiers sent.\n");
+
+ return ret;
+}
+
+/*
+ * Returns 0 on success, a negative error value in case of an error.
+ *
+ * If a changeset entry apply fails, an attempt is made to revert any
+ * previous entries in the changeset. If any of the reverts fails,
+ * that failure is not reported. Thus the state of the device tree
+ * is unknown if an apply error occurs.
+ */
+static int __of_changeset_apply(struct of_changeset *ocs)
+{
+ int ret, ret_revert = 0;
+
+ ret = __of_changeset_apply_entries(ocs, &ret_revert);
+ if (!ret)
+ ret = __of_changeset_apply_notify(ocs);
+
+ return ret;
+}
+
+/**
+ * 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
+ * success, 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)
+{
+ int ret;
+
+ mutex_lock(&of_mutex);
+ ret = __of_changeset_apply(ocs);
+ mutex_unlock(&of_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_apply);
+
+/*
+ * Revert the changeset entries in @ocs.
+ * If revert fails, an attempt is made to re-apply the entries that were
+ * successfully removed.
+ *
+ * If multiple re-apply errors occur then only the final apply error is
+ * reported.
+ *
+ * Returns 0 on success, a negative error value in case of an error.
+ * If an apply error occurs, it is returned in *ret_apply.
+ */
+int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
+{
+ struct of_changeset_entry *ce;
+ int ret, ret_tmp;
+
+ pr_debug("changeset: reverting...\n");
+ list_for_each_entry_reverse(ce, &ocs->entries, node) {
+ ret = __of_changeset_entry_revert(ce);
+ if (ret) {
+ pr_err("Error reverting changeset (%d)\n", ret);
+ list_for_each_entry_continue(ce, &ocs->entries, node) {
+ ret_tmp = __of_changeset_entry_apply(ce);
+ if (ret_tmp)
+ *ret_apply = ret_tmp;
+ }
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * If multiple changeset entry notification errors occur then only the
+ * final notification error is reported.
+ */
+int __of_changeset_revert_notify(struct of_changeset *ocs)
+{
+ struct of_changeset_entry *ce;
+ int ret = 0, ret_tmp;
+
+ pr_debug("changeset: emitting notifiers.\n");
+
+ /* drop the global lock while emitting notifiers */
+ mutex_unlock(&of_mutex);
+ list_for_each_entry_reverse(ce, &ocs->entries, node) {
+ ret_tmp = __of_changeset_entry_notify(ce, 1);
+ if (ret_tmp)
+ ret = ret_tmp;
+ }
+ mutex_lock(&of_mutex);
+ pr_debug("changeset: notifiers sent.\n");
+
+ return ret;
+}
+
+static int __of_changeset_revert(struct of_changeset *ocs)
+{
+ int ret, ret_reply;
+
+ ret_reply = 0;
+ ret = __of_changeset_revert_entries(ocs, &ret_reply);
+
+ if (!ret)
+ ret = __of_changeset_revert_notify(ocs);
+
+ return ret;
+}
+
+/**
+ * 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)
+{
+ int ret;
+
+ mutex_lock(&of_mutex);
+ ret = __of_changeset_revert(ocs);
+ mutex_unlock(&of_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_revert);
+
+/**
+ * of_changeset_action - Add an action to the tail of the changeset list
+ *
+ * @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)
+ 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;
+}
+EXPORT_SYMBOL_GPL(of_changeset_action);