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 */ 10 static 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) */ 16 int 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 23 static void of_node_release(struct kobject *kobj) 24 { 25 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */ 26 } 27 #endif /* CONFIG_OF_DYNAMIC */ 28 29 const struct kobj_type of_node_ktype = { 30 .release = of_node_release, 31 }; 32 EXPORT_SYMBOL_IF_KUNIT(of_node_ktype); 33 34 static 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 */ 43 static 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 66 int __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 90 void __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 99 void __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 } 105 106 void __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 } 117 118 int __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 } 151 152 void __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 } 169