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