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/*
* 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);
}
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