1// SPDX-License-Identifier: GPL-2.0
2#include <linux/of.h>
3#include <linux/slab.h>
4
5#include "of_private.h"
6
7/* true when node is initialized */
8static int of_node_is_initialized(struct device_node *node)
9{
10 return node && node->kobj.state_initialized;
11}
12
13/* true when node is attached (i.e. present on sysfs) */
14int of_node_is_attached(struct device_node *node)
15{
16 return node && node->kobj.state_in_sysfs;
17}
18
19
20#ifndef CONFIG_OF_DYNAMIC
21static void of_node_release(struct kobject *kobj)
22{
23 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
24}
25#endif /* CONFIG_OF_DYNAMIC */
26
27struct kobj_type of_node_ktype = {
28 .release = of_node_release,
29};
30
31static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
32 struct bin_attribute *bin_attr, char *buf,
33 loff_t offset, size_t count)
34{
35 struct property *pp = container_of(bin_attr, struct property, attr);
36 return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
37}
38
39/* always return newly allocated name, caller must free after use */
40static const char *safe_name(struct kobject *kobj, const char *orig_name)
41{
42 const char *name = orig_name;
43 struct kernfs_node *kn;
44 int i = 0;
45
46 /* don't be a hero. After 16 tries give up */
47 while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
48 sysfs_put(kn);
49 if (name != orig_name)
50 kfree(name);
51 name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
52 }
53
54 if (name == orig_name) {
55 name = kstrdup(orig_name, GFP_KERNEL);
56 } else {
57 pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
58 kobject_name(kobj), name);
59 }
60 return name;
61}
62
63int __of_add_property_sysfs(struct device_node *np, struct property *pp)
64{
65 int rc;
66
67 /* Important: Don't leak passwords */
68 bool secure = strncmp(pp->name, "security-", 9) == 0;
69
70 if (!IS_ENABLED(CONFIG_SYSFS))
71 return 0;
72
73 if (!of_kset || !of_node_is_attached(np))
74 return 0;
75
76 sysfs_bin_attr_init(&pp->attr);
77 pp->attr.attr.name = safe_name(&np->kobj, pp->name);
78 pp->attr.attr.mode = secure ? 0400 : 0444;
79 pp->attr.size = secure ? 0 : pp->length;
80 pp->attr.read = of_node_property_read;
81
82 rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
83 WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
84 return rc;
85}
86
87void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
88{
89 if (!IS_ENABLED(CONFIG_SYSFS))
90 return;
91
92 sysfs_remove_bin_file(&np->kobj, &prop->attr);
93 kfree(prop->attr.attr.name);
94}
95
96void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
97{
98 /* at early boot, bail here and defer setup to of_init() */
99 if (of_kset && of_node_is_attached(np))
100 __of_sysfs_remove_bin_file(np, prop);
101}
102
103void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
104 struct property *oldprop)
105{
106 /* At early boot, bail out and defer setup to of_init() */
107 if (!of_kset)
108 return;
109
110 if (oldprop)
111 __of_sysfs_remove_bin_file(np, oldprop);
112 __of_add_property_sysfs(np, newprop);
113}
114
115int __of_attach_node_sysfs(struct device_node *np)
116{
117 const char *name;
118 struct kobject *parent;
119 struct property *pp;
120 int rc;
121
122 if (!of_kset)
123 return 0;
124
125 np->kobj.kset = of_kset;
126 if (!np->parent) {
127 /* Nodes without parents are new top level trees */
128 name = safe_name(&of_kset->kobj, "base");
129 parent = NULL;
130 } else {
131 name = safe_name(&np->parent->kobj, kbasename(np->full_name));
132 parent = &np->parent->kobj;
133 }
134 if (!name)
135 return -ENOMEM;
136
137 of_node_get(np);
138
139 rc = kobject_add(&np->kobj, parent, "%s", name);
140 kfree(name);
141 if (rc)
142 return rc;
143
144 for_each_property_of_node(np, pp)
145 __of_add_property_sysfs(np, pp);
146
147 return 0;
148}
149
150void __of_detach_node_sysfs(struct device_node *np)
151{
152 struct property *pp;
153
154 BUG_ON(!of_node_is_initialized(np));
155 if (!of_kset)
156 return;
157
158 /* only remove properties if on sysfs */
159 if (of_node_is_attached(np)) {
160 for_each_property_of_node(np, pp)
161 __of_sysfs_remove_bin_file(np, pp);
162 kobject_del(&np->kobj);
163 }
164
165 of_node_put(np);
166}
167