of: make kobject and bin_attribute support configurable
Having device_nodes be kobjects is only needed if sysfs or OF_DYNAMIC is
enabled. Otherwise, having a kobject in struct device_node is
unnecessary bloat in minimal kernel configurations.
Likewise, bin_attribute is only needed in struct property when sysfs is
enabled, so we can make it configurable too.
Tested-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Frank Rowand <frowand.list@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c
new file mode 100644
index 0000000..250fc7b
--- /dev/null
+++ b/drivers/of/kobj.c
@@ -0,0 +1,164 @@
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include "of_private.h"
+
+/* true when node is initialized */
+static int of_node_is_initialized(struct device_node *node)
+{
+ return node && node->kobj.state_initialized;
+}
+
+/* true when node is attached (i.e. present on sysfs) */
+int of_node_is_attached(struct device_node *node)
+{
+ return node && node->kobj.state_in_sysfs;
+}
+
+
+#ifndef CONFIG_OF_DYNAMIC
+static void of_node_release(struct kobject *kobj)
+{
+ /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
+}
+#endif /* CONFIG_OF_DYNAMIC */
+
+struct kobj_type of_node_ktype = {
+ .release = of_node_release,
+};
+
+static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t offset, size_t count)
+{
+ struct property *pp = container_of(bin_attr, struct property, attr);
+ return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
+}
+
+/* always return newly allocated name, caller must free after use */
+static const char *safe_name(struct kobject *kobj, const char *orig_name)
+{
+ const char *name = orig_name;
+ struct kernfs_node *kn;
+ int i = 0;
+
+ /* don't be a hero. After 16 tries give up */
+ while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
+ sysfs_put(kn);
+ if (name != orig_name)
+ kfree(name);
+ name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
+ }
+
+ if (name == orig_name) {
+ name = kstrdup(orig_name, GFP_KERNEL);
+ } else {
+ pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
+ kobject_name(kobj), name);
+ }
+ return name;
+}
+
+int __of_add_property_sysfs(struct device_node *np, struct property *pp)
+{
+ int rc;
+
+ /* Important: Don't leak passwords */
+ bool secure = strncmp(pp->name, "security-", 9) == 0;
+
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return 0;
+
+ if (!of_kset || !of_node_is_attached(np))
+ return 0;
+
+ sysfs_bin_attr_init(&pp->attr);
+ pp->attr.attr.name = safe_name(&np->kobj, pp->name);
+ pp->attr.attr.mode = secure ? 0400 : 0444;
+ pp->attr.size = secure ? 0 : pp->length;
+ pp->attr.read = of_node_property_read;
+
+ rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
+ WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
+ return rc;
+}
+
+void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
+{
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return;
+
+ sysfs_remove_bin_file(&np->kobj, &prop->attr);
+ kfree(prop->attr.attr.name);
+}
+
+void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
+{
+ /* at early boot, bail here and defer setup to of_init() */
+ if (of_kset && of_node_is_attached(np))
+ __of_sysfs_remove_bin_file(np, prop);
+}
+
+void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
+ struct property *oldprop)
+{
+ /* At early boot, bail out and defer setup to of_init() */
+ if (!of_kset)
+ return;
+
+ if (oldprop)
+ __of_sysfs_remove_bin_file(np, oldprop);
+ __of_add_property_sysfs(np, newprop);
+}
+
+int __of_attach_node_sysfs(struct device_node *np)
+{
+ const char *name;
+ struct kobject *parent;
+ struct property *pp;
+ int rc;
+
+ if (!of_kset)
+ return 0;
+
+ np->kobj.kset = of_kset;
+ if (!np->parent) {
+ /* Nodes without parents are new top level trees */
+ name = safe_name(&of_kset->kobj, "base");
+ parent = NULL;
+ } else {
+ name = safe_name(&np->parent->kobj, kbasename(np->full_name));
+ parent = &np->parent->kobj;
+ }
+ if (!name)
+ return -ENOMEM;
+ rc = kobject_add(&np->kobj, parent, "%s", name);
+ kfree(name);
+ if (rc)
+ return rc;
+
+ for_each_property_of_node(np, pp)
+ __of_add_property_sysfs(np, pp);
+
+ return 0;
+}
+
+void __of_detach_node_sysfs(struct device_node *np)
+{
+ struct property *pp;
+
+ BUG_ON(!of_node_is_initialized(np));
+ if (!of_kset)
+ return;
+
+ /* only remove properties if on sysfs */
+ if (of_node_is_attached(np)) {
+ for_each_property_of_node(np, pp)
+ __of_sysfs_remove_bin_file(np, pp);
+ kobject_del(&np->kobj);
+ }
+
+ /* finally remove the kobj_init ref */
+ of_node_put(np);
+}
+