LXR linux/drivers/of/kobj.c

   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 */
   8static int of_node_is_initialized(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) */
  14int of_node_is_attached(struct device_node *node)
  15{
  16        return node && node->kobj.state_in_sysfs;
  17}
  18
  19
  20#ifndef CONFIG_OF_DYNAMIC
  21static void of_node_release(struct kobject *kobj)
  22{
  23        /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
  24}
  25#endif /* CONFIG_OF_DYNAMIC */
  26
  27struct kobj_type of_node_ktype = {
  28        .release = of_node_release,
  29};
  30
  31static 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 */
  40static 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
  63int __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
  87void __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
  96void __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
 103void __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
 115int __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
 149void __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