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 */ 8 static int of_node_is_initialized(const 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) */ 14 int of_node_is_attached(const struct device_node *node) 15 { 16 return node && node->kobj.state_in_sysfs; 17 } 18 19 20 #ifndef CONFIG_OF_DYNAMIC 21 static void of_node_release(struct kobject *kobj) 22 { 23 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */ 24 } 25 #endif /* CONFIG_OF_DYNAMIC */ 26 27 const struct kobj_type of_node_ktype = { 28 .release = of_node_release, 29 }; 30 31 static 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 */ 40 static 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 63 int __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 87 void __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 96 void __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 } 102 103 void __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 } 114 115 int __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 (!IS_ENABLED(CONFIG_SYSFS) || !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 rc = kobject_add(&np->kobj, parent, "%s", name); 138 kfree(name); 139 if (rc) 140 return rc; 141 142 for_each_property_of_node(np, pp) 143 __of_add_property_sysfs(np, pp); 144 145 of_node_get(np); 146 return 0; 147 } 148 149 void __of_detach_node_sysfs(struct device_node *np) 150 { 151 struct property *pp; 152 153 BUG_ON(!of_node_is_initialized(np)); 154 if (!of_kset) 155 return; 156 157 /* only remove properties if on sysfs */ 158 if (of_node_is_attached(np)) { 159 for_each_property_of_node(np, pp) 160 __of_sysfs_remove_bin_file(np, pp); 161 kobject_del(&np->kobj); 162 } 163 164 of_node_put(np); 165 } 166