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// SPDX-License-Identifier: GPL-2.0
#include <linux/of.h>
#include <linux/slab.h>
#include "of_private.h"
/* true when node is initialized */
static int of_node_is_initialized(struct device_node *node)
{
return node && node->kobj.state_initialized;
}
/* true when node is attached (i.e. present on sysfs) */
int of_node_is_attached(struct device_node *node)
{
return node && node->kobj.state_in_sysfs;
}
#ifndef CONFIG_OF_DYNAMIC
static void of_node_release(struct kobject *kobj)
{
/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
}
#endif /* CONFIG_OF_DYNAMIC */
struct kobj_type of_node_ktype = {
.release = of_node_release,
};
static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t offset, size_t count)
{
struct property *pp = container_of(bin_attr, struct property, attr);
return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
}
/* always return newly allocated name, caller must free after use */
static const char *safe_name(struct kobject *kobj, const char *orig_name)
{
const char *name = orig_name;
struct kernfs_node *kn;
int i = 0;
/* don't be a hero. After 16 tries give up */
while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
sysfs_put(kn);
if (name != orig_name)
kfree(name);
name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
}
if (name == orig_name) {
name = kstrdup(orig_name, GFP_KERNEL);
} else {
pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
kobject_name(kobj), name);
}
return name;
}
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 (!IS_ENABLED(CONFIG_SYSFS))
return 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 ? 0400 : 0444;
pp->attr.size = secure ? 0 : pp->length;
pp->attr.read = of_node_property_read;
rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
return rc;
}
void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
{
if (!IS_ENABLED(CONFIG_SYSFS))
return;
sysfs_remove_bin_file(&np->kobj, &prop->attr);
kfree(prop->attr.attr.name);
}
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))
__of_sysfs_remove_bin_file(np, prop);
}
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;
if (oldprop)
__of_sysfs_remove_bin_file(np, oldprop);
__of_add_property_sysfs(np, newprop);
}
int __of_attach_node_sysfs(struct device_node *np)
{
const char *name;
struct kobject *parent;
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 */
name = safe_name(&of_kset->kobj, "base");
parent = NULL;
} else {
name = safe_name(&np->parent->kobj, kbasename(np->full_name));
parent = &np->parent->kobj;
}
if (!name)
return -ENOMEM;
rc = kobject_add(&np->kobj, parent, "%s", name);
kfree(name);
if (rc)
return rc;
for_each_property_of_node(np, pp)
__of_add_property_sysfs(np, pp);
return 0;
}
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)
__of_sysfs_remove_bin_file(np, pp);
kobject_del(&np->kobj);
}
/* finally remove the kobj_init ref */
of_node_put(np);
}
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