of: Move CONFIG_OF_DYNAMIC code into a separate file

Split the dynamic device tree code into a separate file to make it
really clear what features CONFIF_OF_DYNAMIC add to the kernel. Without
CONFIG_OF_DYNAMIC only properties can be changed, and notifiers do not
get sent. Enabling it turns on reference counting, notifiers and the
ability to add and remove nodes.

v2: Moved of_node_release() into dynamic.c

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Rob Herring <robh+dt@kernel.org>

1 files changed, 216 insertions, 0 deletions

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
new file mode 100644
index 000000000000..125994330437
--- /dev/null
+++ b/drivers/of/dynamic.c
@@ -0,0 +1,216 @@
+/*
+ * 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);
+
+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);
+}
+
+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 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);
+}
+
+/**
+ * of_attach_node() - Plug a device node into the tree and global list.
+ */
+int of_attach_node(struct device_node *np)
+{
+        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;
+
+        rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
+        if (rc)
+                return rc;
+
+        raw_spin_lock_irqsave(&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 (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);
+        raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+        of_node_remove(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);
+}