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168 lines · 4.0 KiB

1// SPDX-License-Identifier: GPL-2.0
2#include <linux/of.h>
3#include <linux/slab.h>
4
5#include <kunit/visibility.h>
6
7#include "of_private.h"
8
9/* true when node is initialized */
10static int of_node_is_initialized(const struct device_node *node)
11{
12 return node && node->kobj.state_initialized;
13}
14
15/* true when node is attached (i.e. present on sysfs) */
16int of_node_is_attached(const struct device_node *node)
17{
18 return node && node->kobj.state_in_sysfs;
19}
20
21
22#ifndef CONFIG_OF_DYNAMIC
23static void of_node_release(struct kobject *kobj)
24{
25 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
26}
27#endif /* CONFIG_OF_DYNAMIC */
28
29const struct kobj_type of_node_ktype = {
30 .release = of_node_release,
31};
32EXPORT_SYMBOL_IF_KUNIT(of_node_ktype);
33
34static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
35 const struct bin_attribute *bin_attr, char *buf,
36 loff_t offset, size_t count)
37{
38 struct property *pp = container_of(bin_attr, struct property, attr);
39 return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
40}
41
42/* always return newly allocated name, caller must free after use */
43static const char *safe_name(const struct kobject *kobj, const char *orig_name)
44{
45 const char *name = orig_name;
46 struct kernfs_node *kn;
47 int i = 0;
48
49 /* don't be a hero. After 16 tries give up */
50 while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
51 sysfs_put(kn);
52 if (name != orig_name)
53 kfree(name);
54 name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
55 }
56
57 if (name == orig_name) {
58 name = kstrdup(orig_name, GFP_KERNEL);
59 } else {
60 pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
61 kobject_name(kobj), name);
62 }
63 return name;
64}
65
66int __of_add_property_sysfs(struct device_node *np, struct property *pp)
67{
68 int rc;
69
70 /* Important: Don't leak passwords */
71 bool secure = strncmp(pp->name, "security-", 9) == 0;
72
73 if (!IS_ENABLED(CONFIG_SYSFS))
74 return 0;
75
76 if (!of_kset || !of_node_is_attached(np))
77 return 0;
78
79 sysfs_bin_attr_init(&pp->attr);
80 pp->attr.attr.name = safe_name(&np->kobj, pp->name);
81 pp->attr.attr.mode = secure ? 0400 : 0444;
82 pp->attr.size = secure ? 0 : pp->length;
83 pp->attr.read = of_node_property_read;
84
85 rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
86 WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
87 return rc;
88}
89
90void __of_sysfs_remove_bin_file(struct device_node *np, const struct property *prop)
91{
92 if (!IS_ENABLED(CONFIG_SYSFS))
93 return;
94
95 sysfs_remove_bin_file(&np->kobj, &prop->attr);
96 kfree(prop->attr.attr.name);
97}
98
99void __of_remove_property_sysfs(struct device_node *np, const struct property *prop)
100{
101 /* at early boot, bail here and defer setup to of_init() */
102 if (of_kset && of_node_is_attached(np))
103 __of_sysfs_remove_bin_file(np, prop);
104}
105
106void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
107 const struct property *oldprop)
108{
109 /* At early boot, bail out and defer setup to of_init() */
110 if (!of_kset)
111 return;
112
113 if (oldprop)
114 __of_sysfs_remove_bin_file(np, oldprop);
115 __of_add_property_sysfs(np, newprop);
116}
117
118int __of_attach_node_sysfs(struct device_node *np)
119{
120 const char *name;
121 struct kobject *parent;
122 struct property *pp;
123 int rc;
124
125 if (!IS_ENABLED(CONFIG_SYSFS) || !of_kset)
126 return 0;
127
128 np->kobj.kset = of_kset;
129 if (!np->parent) {
130 /* Nodes without parents are new top level trees */
131 name = safe_name(&of_kset->kobj, "base");
132 parent = NULL;
133 } else {
134 name = safe_name(&np->parent->kobj, kbasename(np->full_name));
135 parent = &np->parent->kobj;
136 }
137 if (!name)
138 return -ENOMEM;
139
140 rc = kobject_add(&np->kobj, parent, "%s", name);
141 kfree(name);
142 if (rc)
143 return rc;
144
145 for_each_property_of_node(np, pp)
146 __of_add_property_sysfs(np, pp);
147
148 of_node_get(np);
149 return 0;
150}
151
152void __of_detach_node_sysfs(struct device_node *np)
153{
154 struct property *pp;
155
156 BUG_ON(!of_node_is_initialized(np));
157 if (!of_kset)
158 return;
159
160 /* only remove properties if on sysfs */
161 if (of_node_is_attached(np)) {
162 for_each_property_of_node(np, pp)
163 __of_sysfs_remove_bin_file(np, pp);
164 kobject_del(&np->kobj);
165 }
166
167 of_node_put(np);
168}