diff options
Diffstat (limited to 'drivers/of/kobj.c')
| -rw-r--r-- | drivers/of/kobj.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c new file mode 100644 index 000000000..6675b5e56 --- /dev/null +++ b/drivers/of/kobj.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0 +#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 (!IS_ENABLED(CONFIG_SYSFS) || !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); + + of_node_get(np); + 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); + } + + of_node_put(np); +} |