Merge branch 'devicetree/next-overlay' into devicetree/next

Conflicts:
	drivers/of/testcase-data/testcases.dts

Documentation/devicetree/changesets.txt

+A DT changeset is a method which allows one to apply changes
+in the live tree in such a way that either the full set of changes
+will be applied, or none of them will be. If an error occurs partway
+through applying the changeset, then the tree will be rolled back to the
+previous state. A changeset can also be removed after it has been
+applied.
+
+When a changeset is applied, all of the changes get applied to the tree
+at once before emitting OF_RECONFIG notifiers. This is so that the
+receiver sees a complete and consistent state of the tree when it
+receives the notifier.
+
+The sequence of a changeset is as follows.
+
+1. of_changeset_init() - initializes a changeset
+
+2. A number of DT tree change calls, of_changeset_attach_node(),
+of_changeset_detach_node(), of_changeset_add_property(),
+of_changeset_remove_property, of_changeset_update_property() to prepare
+a set of changes. No changes to the active tree are made at this point.
+All the change operations are recorded in the of_changeset 'entries'
+list.
+
+3. mutex_lock(of_mutex) - starts a changeset; The global of_mutex
+ensures there can only be one editor at a time.
+
+4. of_changeset_apply() - Apply the changes to the tree. Either the
+entire changeset will get applied, or if there is an error the tree will
+be restored to the previous state
+
+5. mutex_unlock(of_mutex) - All operations complete, release the mutex
+
+If a successfully applied changeset needs to be removed, it can be done
+with the following sequence.
+
+1. mutex_lock(of_mutex)
+
+2. of_changeset_revert()
+
+3. mutex_unlock(of_mutex)

arch/powerpc/kernel/prom.c

@@ -821,76 +821,6 @@ int cpu_to_chip_id(int cpu)
 }
 EXPORT_SYMBOL(cpu_to_chip_id);
 
-#ifdef CONFIG_PPC_PSERIES
-/*
- * Fix up the uninitialized fields in a new device node:
- * name, type and pci-specific fields
- */
-
-static int of_finish_dynamic_node(struct device_node *node)
-{
-	struct device_node *parent = of_get_parent(node);
-	int err = 0;
-	const phandle *ibm_phandle;
-
-	node->name = of_get_property(node, "name", NULL);
-	node->type = of_get_property(node, "device_type", NULL);
-
-	if (!node->name)
-		node->name = "<NULL>";
-	if (!node->type)
-		node->type = "<NULL>";
-
-	if (!parent) {
-		err = -ENODEV;
-		goto out;
-	}
-
-	/* We don't support that function on PowerMac, at least
-	 * not yet
-	 */
-	if (machine_is(powermac))
-		return -ENODEV;
-
-	/* fix up new node's phandle field */
-	if ((ibm_phandle = of_get_property(node, "ibm,phandle", NULL)))
-		node->phandle = *ibm_phandle;
-
-out:
-	of_node_put(parent);
-	return err;
-}
-
-static int prom_reconfig_notifier(struct notifier_block *nb,
-				  unsigned long action, void *node)
-{
-	int err;
-
-	switch (action) {
-	case OF_RECONFIG_ATTACH_NODE:
-		err = of_finish_dynamic_node(node);
-		if (err < 0)
-			printk(KERN_ERR "finish_node returned %d\n", err);
-		break;
-	default:
-		err = 0;
-		break;
-	}
-	return notifier_from_errno(err);
-}
-
-static struct notifier_block prom_reconfig_nb = {
-	.notifier_call = prom_reconfig_notifier,
-	.priority = 10, /* This one needs to run first */
-};
-
-static int __init prom_reconfig_setup(void)
-{
-	return of_reconfig_notifier_register(&prom_reconfig_nb);
-}
-__initcall(prom_reconfig_setup);
-#endif
-
 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
 	return (int)phys_id == get_hard_smp_processor_id(cpu);

arch/powerpc/platforms/pseries/hotplug-memory.c

@@ -194,7 +194,7 @@ static int pseries_update_drconf_memory(struct of_prop_reconfig *pr)
 	if (!memblock_size)
 		return -EINVAL;
 
-	p = (u32 *)of_get_property(pr->dn, "ibm,dynamic-memory", NULL);
+	p = (u32 *) pr->old_prop->value;
 	if (!p)
 		return -EINVAL;
 

drivers/crypto/nx/nx-842.c

@@ -936,28 +936,14 @@ static int nx842_OF_upd(struct property *new_prop)
 		goto error_out;
 	}
 
-	/* Set ptr to new property if provided */
-	if (new_prop) {
-		/* Single property */
-		if (!strncmp(new_prop->name, "status", new_prop->length)) {
-			status = new_prop;
-
-		} else if (!strncmp(new_prop->name, "ibm,max-sg-len",
-					new_prop->length)) {
-			maxsglen = new_prop;
-
-		} else if (!strncmp(new_prop->name, "ibm,max-sync-cop",
-					new_prop->length)) {
-			maxsyncop = new_prop;
-
-		} else {
-			/*
-			 * Skip the update, the property being updated
-			 * has no impact.
-			 */
-			goto out;
-		}
-	}
+	/*
+	 * If this is a property update, there are only certain properties that
+	 * we care about. Bail if it isn't in the below list
+	 */
+	if (new_prop && (strncmp(new_prop->name, "status", new_prop->length) ||
+		         strncmp(new_prop->name, "ibm,max-sg-len", new_prop->length) ||
+		         strncmp(new_prop->name, "ibm,max-sync-cop", new_prop->length)))
+		goto out;
 
 	/* Perform property updates */
 	ret = nx842_OF_upd_status(new_devdata, status);

drivers/of/Makefile

 obj-y = base.o device.o platform.o
+obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
 obj-$(CONFIG_OF_FLATTREE) += fdt.o
 obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
 obj-$(CONFIG_OF_PROMTREE) += pdt.o

drivers/of/base.c

@@ -38,13 +38,15 @@ struct device_node *of_chosen;
 struct device_node *of_aliases;
 struct device_node *of_stdout;
 
-static struct kset *of_kset;
+struct kset *of_kset;
 
 /*
- * Used to protect the of_aliases; but also overloaded to hold off addition of
- * nodes to sysfs
+ * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
+ * This mutex must be held whenever modifications are being made to the
+ * device tree. The of_{attach,detach}_node() and
+ * of_{add,remove,update}_property() helpers make sure this happens.
  */
-DEFINE_MUTEX(of_aliases_mutex);
+DEFINE_MUTEX(of_mutex);
 
 /* use when traversing tree through the allnext, child, sibling,
  * or parent members of struct device_node.
@@ -90,79 +92,7 @@ int __weak of_node_to_nid(struct device_node *np)
 }
 #endif
 
-#if defined(CONFIG_OF_DYNAMIC)
-/**
- *	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);
-
-static inline struct device_node *kobj_to_device_node(struct kobject *kobj)
-{
-	return container_of(kobj, struct device_node, kobj);
-}
-
-/**
- *	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.
- */
-static void of_node_release(struct kobject *kobj)
-{
-	struct device_node *node = kobj_to_device_node(kobj);
-	struct property *prop = node->properties;
-
-	/* 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 %s\n", node->full_name);
-		dump_stack();
-		return;
-	}
-
-	if (!of_node_check_flag(node, OF_DYNAMIC))
-		return;
-
-	while (prop) {
-		struct property *next = prop->next;
-		kfree(prop->name);
-		kfree(prop->value);
-		kfree(prop);
-		prop = next;
-
-		if (!prop) {
-			prop = node->deadprops;
-			node->deadprops = NULL;
-		}
-	}
-	kfree(node->full_name);
-	kfree(node->data);
-	kfree(node);
-}
-
-/**
- *	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);
-#else
+#ifndef CONFIG_OF_DYNAMIC
 static void of_node_release(struct kobject *kobj)
 {
 	/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
@@ -201,13 +131,16 @@ static const char *safe_name(struct kobject *kobj, const char *orig_name)
 	return name;
 }
 
-static int __of_add_property_sysfs(struct device_node *np, struct property *pp)
+int __of_add_property_sysfs(struct device_node *np, struct property *pp)
 {
 	int rc;
 
 	/* Important: Don't leak passwords */
 	bool secure = strncmp(pp->name, "security-", 9) == 0;
 
+	if (!of_kset || !of_node_is_attached(np))
+		return 0;
+
 	sysfs_bin_attr_init(&pp->attr);
 	pp->attr.attr.name = safe_name(&np->kobj, pp->name);
 	pp->attr.attr.mode = secure ? S_IRUSR : S_IRUGO;
@@ -219,12 +152,15 @@ static int __of_add_property_sysfs(struct device_node *np, struct property *pp)
 	return rc;
 }
 
-static int __of_node_add(struct device_node *np)
+int __of_attach_node_sysfs(struct device_node *np)
 {
 	const char *name;
 	struct property *pp;
 	int rc;
 
+	if (!of_kset)
+		return 0;
+
 	np->kobj.kset = of_kset;
 	if (!np->parent) {
 		/* Nodes without parents are new top level trees */
@@ -246,59 +182,20 @@ static int __of_node_add(struct device_node *np)
 	return 0;
 }
 
-int of_node_add(struct device_node *np)
-{
-	int rc = 0;
-
-	BUG_ON(!of_node_is_initialized(np));
-
-	/*
-	 * Grab the mutex here so that in a race condition between of_init() and
-	 * of_node_add(), node addition will still be consistent.
-	 */
-	mutex_lock(&of_aliases_mutex);
-	if (of_kset)
-		rc = __of_node_add(np);
-	else
-		/* This scenario may be perfectly valid, but report it anyway */
-		pr_info("of_node_add(%s) before of_init()\n", np->full_name);
-	mutex_unlock(&of_aliases_mutex);
-	return rc;
-}
-
-#if defined(CONFIG_OF_DYNAMIC)
-static void of_node_remove(struct device_node *np)
-{
-	struct property *pp;
-
-	BUG_ON(!of_node_is_initialized(np));
-
-	/* only remove properties if on sysfs */
-	if (of_node_is_attached(np)) {
-		for_each_property_of_node(np, pp)
-			sysfs_remove_bin_file(&np->kobj, &pp->attr);
-		kobject_del(&np->kobj);
-	}
-
-	/* finally remove the kobj_init ref */
-	of_node_put(np);
-}
-#endif
-
 static int __init of_init(void)
 {
 	struct device_node *np;
 
 	/* Create the kset, and register existing nodes */
-	mutex_lock(&of_aliases_mutex);
+	mutex_lock(&of_mutex);
 	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
 	if (!of_kset) {
-		mutex_unlock(&of_aliases_mutex);
+		mutex_unlock(&of_mutex);
 		return -ENOMEM;
 	}
 	for_each_of_allnodes(np)
-		__of_node_add(np);
-	mutex_unlock(&of_aliases_mutex);
+		__of_attach_node_sysfs(np);
+	mutex_unlock(&of_mutex);
 
 	/* Symlink in /proc as required by userspace ABI */
 	if (of_allnodes)
@@ -370,8 +267,8 @@ EXPORT_SYMBOL(of_find_all_nodes);
  * Find a property with a given name for a given node
  * and return the value.
  */
-static const void *__of_get_property(const struct device_node *np,
-				     const char *name, int *lenp)
+const void *__of_get_property(const struct device_node *np,
+			      const char *name, int *lenp)
 {
 	struct property *pp = __of_find_property(np, name, lenp);
 
@@ -1749,32 +1646,10 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na
 }
 EXPORT_SYMBOL(of_count_phandle_with_args);
 
-#if defined(CONFIG_OF_DYNAMIC)
-static int of_property_notify(int action, struct device_node *np,
-			      struct property *prop)
-{
-	struct of_prop_reconfig pr;
-
-	/* only call notifiers if the node is attached */
-	if (!of_node_is_attached(np))
-		return 0;
-
-	pr.dn = np;
-	pr.prop = prop;
-	return of_reconfig_notify(action, &pr);
-}
-#else
-static int of_property_notify(int action, struct device_node *np,
-			      struct property *prop)
-{
-	return 0;
-}
-#endif
-
 /**
  * __of_add_property - Add a property to a node without lock operations
  */
-static int __of_add_property(struct device_node *np, struct property *prop)
+int __of_add_property(struct device_node *np, struct property *prop)
 {
 	struct property **next;
 
@@ -1800,22 +1675,49 @@ int of_add_property(struct device_node *np, struct property *prop)
 	unsigned long flags;
 	int rc;
 
-	rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
-	if (rc)
-		return rc;
+	mutex_lock(&of_mutex);
 
 	raw_spin_lock_irqsave(&devtree_lock, flags);
 	rc = __of_add_property(np, prop);
 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
-	if (rc)
-		return rc;
 
-	if (of_node_is_attached(np))
+	if (!rc)
 		__of_add_property_sysfs(np, prop);
 
+	mutex_unlock(&of_mutex);
+
+	if (!rc)
+		of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
+
 	return rc;
 }
 
+int __of_remove_property(struct device_node *np, struct property *prop)
+{
+	struct property **next;
+
+	for (next = &np->properties; *next; next = &(*next)->next) {
+		if (*next == prop)
+			break;
+	}
+	if (*next == NULL)
+		return -ENODEV;
+
+	/* found the node */
+	*next = prop->next;
+	prop->next = np->deadprops;
+	np->deadprops = prop;
+
+	return 0;
+}
+
+void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
+{
+	/* at early boot, bail here and defer setup to of_init() */
+	if (of_kset && of_node_is_attached(np))
+		sysfs_remove_bin_file(&np->kobj, &prop->attr);
+}
+
 /**
  * of_remove_property - Remove a property from a node.
  *
@@ -1826,211 +1728,98 @@ int of_add_property(struct device_node *np, struct property *prop)
  */
 int of_remove_property(struct device_node *np, struct property *prop)
 {
-	struct property **next;
 	unsigned long flags;
-	int found = 0;
 	int rc;
 
-	rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
-	if (rc)
-		return rc;
+	mutex_lock(&of_mutex);
 
 	raw_spin_lock_irqsave(&devtree_lock, flags);
-	next = &np->properties;
-	while (*next) {
-		if (*next == prop) {
-			/* found the node */
-			*next = prop->next;
-			prop->next = np->deadprops;
-			np->deadprops = prop;
-			found = 1;
-			break;
-		}
-		next = &(*next)->next;
-	}
+	rc = __of_remove_property(np, prop);
 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
-	if (!found)
-		return -ENODEV;
+	if (!rc)
+		__of_remove_property_sysfs(np, prop);
 
-	/* at early boot, bail hear and defer setup to of_init() */
-	if (!of_kset)
-		return 0;
+	mutex_unlock(&of_mutex);
 
-	sysfs_remove_bin_file(&np->kobj, &prop->attr);
+	if (!rc)
+		of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
 
-	return 0;
+	return rc;
 }
 
-/*
- * of_update_property - Update a property in a node, if the property does
- * not exist, add it.
- *
- * Note that we don't actually remove it, since we have given out
- * who-knows-how-many pointers to the data using get-property.
- * Instead we just move the property to the "dead properties" list,
- * and add the new property to the property list
- */
-int of_update_property(struct device_node *np, struct property *newprop)
+int __of_update_property(struct device_node *np, struct property *newprop,
+		struct property **oldpropp)
 {
 	struct property **next, *oldprop;
-	unsigned long flags;
-	int rc;
-
-	rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
-	if (rc)
-		return rc;
 
-	if (!newprop->name)
-		return -EINVAL;
+	for (next = &np->properties; *next; next = &(*next)->next) {
+		if (of_prop_cmp((*next)->name, newprop->name) == 0)
+			break;
+	}
+	*oldpropp = oldprop = *next;
 
-	raw_spin_lock_irqsave(&devtree_lock, flags);
-	next = &np->properties;
-	oldprop = __of_find_property(np, newprop->name, NULL);
-	if (!oldprop) {
-		/* add the new node */
-		rc = __of_add_property(np, newprop);
-	} else while (*next) {
+	if (oldprop) {
 		/* replace the node */
-		if (*next == oldprop) {
-			newprop->next = oldprop->next;
-			*next = newprop;
-			oldprop->next = np->deadprops;
-			np->deadprops = oldprop;
-			break;
-		}
-		next = &(*next)->next;
+		newprop->next = oldprop->next;
+		*next = newprop;
+		oldprop->next = np->deadprops;
+		np->deadprops = oldprop;
+	} else {
+		/* new node */
+		newprop->next = NULL;
+		*next = newprop;
 	}
-	raw_spin_unlock_irqrestore(&devtree_lock, flags);
-	if (rc)
-		return rc;
 
+	return 0;
+}
+
+void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
+		struct property *oldprop)
+{
 	/* At early boot, bail out and defer setup to of_init() */
 	if (!of_kset)
-		return 0;
+		return;
 
-	/* Update the sysfs attribute */
 	if (oldprop)
 		sysfs_remove_bin_file(&np->kobj, &oldprop->attr);
 	__of_add_property_sysfs(np, newprop);
-
-	return 0;
 }
 
-#if defined(CONFIG_OF_DYNAMIC)
 /*
- * Support for dynamic device trees.
+ * of_update_property - Update a property in a node, if the property does
+ * not exist, add it.
  *
- * On some platforms, the device tree can be manipulated at runtime.
- * The routines in this section support adding, removing and changing
- * device tree nodes.
- */
-
-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);
-
-int of_reconfig_notify(unsigned long action, void *p)
-{
-	int rc;
-
-	rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
-	return notifier_to_errno(rc);
-}
-
-/**
- * of_attach_node - Plug a device node into the tree and global list.
+ * Note that we don't actually remove it, since we have given out
+ * who-knows-how-many pointers to the data using get-property.
+ * Instead we just move the property to the "dead properties" list,
+ * and add the new property to the property list
  */
-int of_attach_node(struct device_node *np)
+int of_update_property(struct device_node *np, struct property *newprop)
 {
+	struct property *oldprop;
 	unsigned long flags;
 	int rc;
 
-	rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
-	if (rc)
-		return rc;
-
-	raw_spin_lock_irqsave(&devtree_lock, flags);
-	np->sibling = np->parent->child;
-	np->allnext = np->parent->allnext;
-	np->parent->allnext = np;
-	np->parent->child = np;
-	of_node_clear_flag(np, OF_DETACHED);
-	raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
-	of_node_add(np);
-	return 0;
-}
-
-/**
- * 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 device_node *parent;
-	unsigned long flags;
-	int rc = 0;
+	if (!newprop->name)
+		return -EINVAL;
 
-	rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
-	if (rc)
-		return rc;
+	mutex_lock(&of_mutex);
 
 	raw_spin_lock_irqsave(&devtree_lock, flags);
+	rc = __of_update_property(np, newprop, &oldprop);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
-	if (of_node_check_flag(np, OF_DETACHED)) {
-		/* someone already detached it */
-		raw_spin_unlock_irqrestore(&devtree_lock, flags);
-		return rc;
-	}
-
-	parent = np->parent;
-	if (!parent) {
-		raw_spin_unlock_irqrestore(&devtree_lock, flags);
-		return rc;
-	}
-
-	if (of_allnodes == np)
-		of_allnodes = np->allnext;
-	else {
-		struct device_node *prev;
-		for (prev = of_allnodes;
-		     prev->allnext != np;
-		     prev = prev->allnext)
-			;
-		prev->allnext = np->allnext;
-	}
+	if (!rc)
+		__of_update_property_sysfs(np, newprop, oldprop);
 
-	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;
-	}
+	mutex_unlock(&of_mutex);
 
-	of_node_set_flag(np, OF_DETACHED);
-	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	if (!rc)
+		of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
 
-	of_node_remove(np);
 	return rc;
 }
-#endif /* defined(CONFIG_OF_DYNAMIC) */
 
 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
 			 int id, const char *stem, int stem_len)
@@ -2126,7 +1915,7 @@ int of_alias_get_id(struct device_node *np, const char *stem)
 	struct alias_prop *app;
 	int id = -ENODEV;
 
-	mutex_lock(&of_aliases_mutex);
+	mutex_lock(&of_mutex);
 	list_for_each_entry(app, &aliases_lookup, link) {
 		if (strcmp(app->stem, stem) != 0)
 			continue;
@@ -2136,7 +1925,7 @@ int of_alias_get_id(struct device_node *np, const char *stem)
 			break;
 		}
 	}
-	mutex_unlock(&of_aliases_mutex);
+	mutex_unlock(&of_mutex);
 
 	return id;
 }

drivers/of/device.c

@@ -160,7 +160,7 @@ void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 	add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
 
 	seen = 0;
-	mutex_lock(&of_aliases_mutex);
+	mutex_lock(&of_mutex);
 	list_for_each_entry(app, &aliases_lookup, link) {
 		if (dev->of_node == app->np) {
 			add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
@@ -168,7 +168,7 @@ void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 			seen++;
 		}
 	}
-	mutex_unlock(&of_aliases_mutex);
+	mutex_unlock(&of_mutex);
 }
 
 int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)

drivers/of/dynamic.c

+/*
+ * 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.
+ */
+
+#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"
+
+/**
+ * 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);
+
+void __of_detach_node_sysfs(struct device_node *np)
+{
+	struct property *pp;
+
+	BUG_ON(!of_node_is_initialized(np));
+	if (!of_kset)
+		return;
+
+	/* only remove properties if on sysfs */
+	if (of_node_is_attached(np)) {
+		for_each_property_of_node(np, pp)
+			sysfs_remove_bin_file(&np->kobj, &pp->attr);
+		kobject_del(&np->kobj);
+	}
+
+	/* finally remove the kobj_init ref */
+	of_node_put(np);
+}
+
+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);
+
+int of_reconfig_notify(unsigned long action, void *p)
+{
+	int rc;
+
+	rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
+	return notifier_to_errno(rc);
+}
+
+int of_property_notify(int action, struct device_node *np,
+		       struct property *prop, struct property *oldprop)
+{
+	struct of_prop_reconfig 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);
+}
+
+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(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->allnext = np->parent->allnext;
+	np->parent->allnext = np;
+	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)
+{
+	unsigned long flags;
+
+	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, np);
+
+	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 (of_allnodes == np)
+		of_allnodes = np->allnext;
+	else {
+		struct device_node *prev;
+		for (prev = of_allnodes;
+		     prev->allnext != np;
+		     prev = prev->allnext)
+			;
+		prev->allnext = np->allnext;
+	}
+
+	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)
+{
+	unsigned long flags;
+	int rc = 0;
+
+	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, np);
+
+	return rc;
+}
+
+/**
+ * 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);
+	struct property *prop = node->properties;
+
+	/* 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 %s\n", node->full_name);
+		dump_stack();
+		return;
+	}
+
+	if (!of_node_check_flag(node, OF_DYNAMIC))
+		return;
+
+	while (prop) {
+		struct property *next = prop->next;
+		kfree(prop->name);
+		kfree(prop->value);
+		kfree(prop);
+		prop = next;
+
+		if (!prop) {
+			prop = node->deadprops;
+			node->deadprops = NULL;
+		}
+	}
+	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 stucture 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_alloc() - Create an empty device node dynamically.
+ * @full_name:	Full name of the new device node
+ * @allocflags:	Allocation flags (typically pass GFP_KERNEL)
+ *
+ * Create an empty device tree node, suitable for further modification.
+ * 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_alloc(const char *full_name, gfp_t allocflags)
+{
+	struct device_node *node;
+
+	node = kzalloc(sizeof(*node), allocflags);
+	if (!node)
+		return NULL;
+
+	node->full_name = kstrdup(full_name, allocflags);
+	of_node_set_flag(node, OF_DYNAMIC);
+	of_node_set_flag(node, OF_DETACHED);
+	if (!node->full_name)
+		goto err_free;
+
+	of_node_init(node);
+
+	return node;
+
+ err_free:
+	kfree(node->full_name);
+	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;
+}

drivers/of/of_private.h

@@ -31,6 +31,63 @@ struct alias_prop {
 	char stem[0];
 };
 
-extern struct mutex of_aliases_mutex;
+extern struct mutex of_mutex;
 extern struct list_head aliases_lookup;
+extern struct kset *of_kset;
+
+
+static inline struct device_node *kobj_to_device_node(struct kobject *kobj)
+{
+	return container_of(kobj, struct device_node, kobj);
+}
+
+#if defined(CONFIG_OF_DYNAMIC)
+extern int of_property_notify(int action, struct device_node *np,
+			      struct property *prop, struct property *old_prop);
+extern void of_node_release(struct kobject *kobj);
+#else /* CONFIG_OF_DYNAMIC */
+static inline int of_property_notify(int action, struct device_node *np,
+				     struct property *prop, struct property *old_prop)
+{
+	return 0;
+}
+#endif /* CONFIG_OF_DYNAMIC */
+
+/**
+ * General utilities for working with live trees.
+ *
+ * All functions with two leading underscores operate
+ * without taking node references, so you either have to
+ * own the devtree lock or work on detached trees only.
+ */
+struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags);
+struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags);
+
+extern const void *__of_get_property(const struct device_node *np,
+				     const char *name, int *lenp);
+extern int __of_add_property(struct device_node *np, struct property *prop);
+extern int __of_add_property_sysfs(struct device_node *np,
+		struct property *prop);
+extern int __of_remove_property(struct device_node *np, struct property *prop);
+extern void __of_remove_property_sysfs(struct device_node *np,
+		struct property *prop);
+extern int __of_update_property(struct device_node *np,
+		struct property *newprop, struct property **oldprop);
+extern void __of_update_property_sysfs(struct device_node *np,
+		struct property *newprop, struct property *oldprop);
+
+extern void __of_attach_node(struct device_node *np);
+extern int __of_attach_node_sysfs(struct device_node *np);
+extern void __of_detach_node(struct device_node *np);
+extern void __of_detach_node_sysfs(struct device_node *np);
+
+/* iterators for transactions, used for overlays */
+/* forward iterator */
+#define for_each_transaction_entry(_oft, _te) \
+	list_for_each_entry(_te, &(_oft)->te_list, node)
+
+/* reverse iterator */
+#define for_each_transaction_entry_reverse(_oft, _te) \
+	list_for_each_entry_reverse(_te, &(_oft)->te_list, node)
+
 #endif /* _LINUX_OF_PRIVATE_H */

drivers/of/platform.c

@@ -422,6 +422,7 @@ static int of_platform_bus_create(struct device_node *bus,
 			break;
 		}
 	}
+	of_node_set_flag(bus, OF_POPULATED_BUS);
 	return rc;
 }
 
@@ -508,19 +509,13 @@ EXPORT_SYMBOL_GPL(of_platform_populate);
 
 static int of_platform_device_destroy(struct device *dev, void *data)
 {
-	bool *children_left = data;
-
 	/* Do not touch devices not populated from the device tree */
-	if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED)) {
-		*children_left = true;
+	if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
 		return 0;
-	}
 
-	/* Recurse, but don't touch this device if it has any children left */
-	if (of_platform_depopulate(dev) != 0) {
-		*children_left = true;
-		return 0;
-	}
+	/* Recurse for any nodes that were treated as busses */
+	if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
+		device_for_each_child(dev, NULL, of_platform_device_destroy);
 
 	if (dev->bus == &platform_bus_type)
 		platform_device_unregister(to_platform_device(dev));
@@ -528,19 +523,15 @@ static int of_platform_device_destroy(struct device *dev, void *data)
 	else if (dev->bus == &amba_bustype)
 		amba_device_unregister(to_amba_device(dev));
 #endif
-	else {
-		*children_left = true;
-		return 0;
-	}
 
 	of_node_clear_flag(dev->of_node, OF_POPULATED);
-
+	of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
 	return 0;
 }
 
 /**
  * of_platform_depopulate() - Remove devices populated from device tree
- * @parent: device which childred will be removed
+ * @parent: device which children will be removed
  *
  * Complementary to of_platform_populate(), this function removes children
  * of the given device (and, recurrently, their children) that have been
@@ -550,14 +541,9 @@ static int of_platform_device_destroy(struct device *dev, void *data)
  * Returns 0 when all children devices have been removed or
  * -EBUSY when some children remained.
  */
-int of_platform_depopulate(struct device *parent)
+void of_platform_depopulate(struct device *parent)
 {
-	bool children_left = false;
-
-	device_for_each_child(parent, &children_left,
-			      of_platform_device_destroy);
-
-	return children_left ? -EBUSY : 0;
+	device_for_each_child(parent, NULL, of_platform_device_destroy);
 }
 EXPORT_SYMBOL_GPL(of_platform_depopulate);
 

drivers/of/selftest.c

@@ -17,6 +17,8 @@
 #include <linux/slab.h>
 #include <linux/device.h>
 
+#include "of_private.h"
+
 static struct selftest_results {
 	int passed;
 	int failed;
@@ -271,6 +273,81 @@ static void __init of_selftest_property_match_string(void)
 	selftest(rc == -EILSEQ, "unterminated string; rc=%i", rc);
 }
 
+#define propcmp(p1, p2) (((p1)->length == (p2)->length) && \
+			(p1)->value && (p2)->value && \
+			!memcmp((p1)->value, (p2)->value, (p1)->length) && \
+			!strcmp((p1)->name, (p2)->name))
+static void __init of_selftest_property_copy(void)
+{
+#ifdef CONFIG_OF_DYNAMIC
+	struct property p1 = { .name = "p1", .length = 0, .value = "" };
+	struct property p2 = { .name = "p2", .length = 5, .value = "abcd" };
+	struct property *new;
+
+	new = __of_prop_dup(&p1, GFP_KERNEL);
+	selftest(new && propcmp(&p1, new), "empty property didn't copy correctly\n");
+	kfree(new->value);
+	kfree(new->name);
+	kfree(new);
+
+	new = __of_prop_dup(&p2, GFP_KERNEL);
+	selftest(new && propcmp(&p2, new), "non-empty property didn't copy correctly\n");
+	kfree(new->value);
+	kfree(new->name);
+	kfree(new);
+#endif
+}
+
+static void __init of_selftest_changeset(void)
+{
+#ifdef CONFIG_OF_DYNAMIC
+	struct property *ppadd, padd = { .name = "prop-add", .length = 0, .value = "" };
+	struct property *ppupdate, pupdate = { .name = "prop-update", .length = 5, .value = "abcd" };
+	struct property *ppremove;
+	struct device_node *n1, *n2, *n21, *nremove, *parent;
+	struct of_changeset chgset;
+
+	of_changeset_init(&chgset);
+	n1 = __of_node_alloc("/testcase-data/changeset/n1", GFP_KERNEL);
+	selftest(n1, "testcase setup failure\n");
+	n2 = __of_node_alloc("/testcase-data/changeset/n2", GFP_KERNEL);
+	selftest(n2, "testcase setup failure\n");
+	n21 = __of_node_alloc("/testcase-data/changeset/n2/n21", GFP_KERNEL);
+	selftest(n21, "testcase setup failure %p\n", n21);
+	nremove = of_find_node_by_path("/testcase-data/changeset/node-remove");
+	selftest(nremove, "testcase setup failure\n");
+	ppadd = __of_prop_dup(&padd, GFP_KERNEL);
+	selftest(ppadd, "testcase setup failure\n");
+	ppupdate = __of_prop_dup(&pupdate, GFP_KERNEL);
+	selftest(ppupdate, "testcase setup failure\n");
+	parent = nremove->parent;
+	n1->parent = parent;
+	n2->parent = parent;
+	n21->parent = n2;
+	n2->child = n21;
+	ppremove = of_find_property(parent, "prop-remove", NULL);
+	selftest(ppremove, "failed to find removal prop");
+
+	of_changeset_init(&chgset);
+	selftest(!of_changeset_attach_node(&chgset, n1), "fail attach n1\n");
+	selftest(!of_changeset_attach_node(&chgset, n2), "fail attach n2\n");
+	selftest(!of_changeset_detach_node(&chgset, nremove), "fail remove node\n");
+	selftest(!of_changeset_attach_node(&chgset, n21), "fail attach n21\n");
+	selftest(!of_changeset_add_property(&chgset, parent, ppadd), "fail add prop\n");
+	selftest(!of_changeset_update_property(&chgset, parent, ppupdate), "fail update prop\n");
+	selftest(!of_changeset_remove_property(&chgset, parent, ppremove), "fail remove prop\n");
+	mutex_lock(&of_mutex);
+	selftest(!of_changeset_apply(&chgset), "apply failed\n");
+	mutex_unlock(&of_mutex);
+
+	mutex_lock(&of_mutex);
+	selftest(!of_changeset_revert(&chgset), "revert failed\n");
+	mutex_unlock(&of_mutex);
+
+	of_changeset_destroy(&chgset);
+#endif
+}
+
 static void __init of_selftest_parse_interrupts(void)
 {
 	struct device_node *np;
@@ -685,6 +762,8 @@ static int __init of_selftest(void)
 	of_selftest_dynamic();
 	of_selftest_parse_phandle_with_args();
 	of_selftest_property_match_string();
+	of_selftest_property_copy();
+	of_selftest_changeset();
 	of_selftest_parse_interrupts();
 	of_selftest_parse_interrupts_extended();
 	of_selftest_match_node();

drivers/of/testcase-data/testcases.dts

 /dts-v1/;
+/ {
+	testcase-data {
+		changeset {
+			prop-update = "hello";
+			prop-remove = "world";
+			node-remove {
+			};
+		};
+	};
+};
 #include "tests-phandle.dtsi"
 #include "tests-interrupts.dtsi"
 #include "tests-match.dtsi"

include/linux/of.h

@@ -74,8 +74,6 @@ struct of_phandle_args {
 	uint32_t args[MAX_PHANDLE_ARGS];
 };
 
-extern int of_node_add(struct device_node *node);
-
 /* initialize a node */
 extern struct kobj_type of_node_ktype;
 static inline void of_node_init(struct device_node *node)
@@ -205,6 +203,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
 #define OF_DYNAMIC	1 /* node and properties were allocated via kmalloc */
 #define OF_DETACHED	2 /* node has been detached from the device tree */
 #define OF_POPULATED	3 /* device already created for the node */
+#define OF_POPULATED_BUS	4 /* of_platform_populate recursed to children of this node */
 
 #define OF_IS_DYNAMIC(x) test_bit(OF_DYNAMIC, &x->_flags)
 #define OF_MARK_DYNAMIC(x) set_bit(OF_DYNAMIC, &x->_flags)
@@ -323,6 +322,7 @@ extern int of_update_property(struct device_node *np, struct property *newprop);
 struct of_prop_reconfig {
 	struct device_node	*dn;
 	struct property		*prop;
+	struct property		*old_prop;
 };
 
 extern int of_reconfig_notifier_register(struct notifier_block *);
@@ -787,4 +787,80 @@ 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 */

include/linux/of_platform.h

@@ -72,7 +72,7 @@ extern int of_platform_populate(struct device_node *root,
 				const struct of_device_id *matches,
 				const struct of_dev_auxdata *lookup,
 				struct device *parent);
-extern int of_platform_depopulate(struct device *parent);
+extern void of_platform_depopulate(struct device *parent);
 #else
 static inline int of_platform_populate(struct device_node *root,
 					const struct of_device_id *matches,
@@ -81,10 +81,7 @@ static inline int of_platform_populate(struct device_node *root,
 {
 	return -ENODEV;
 }
-static inline int of_platform_depopulate(struct device *parent)
-{
-	return -ENODEV;
-}
+static inline void of_platform_depopulate(struct device *parent) { }
 #endif
 
 #endif	/* _LINUX_OF_PLATFORM_H */