drivers/base/swnode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Software nodes for the firmware node framework.
   4  *
   5  * Copyright (C) 2018, Intel Corporation
   6  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/property.h>
  12 #include <linux/slab.h>
  13
  14 struct swnode {
  15         int id;
  16         struct kobject kobj;
  17         struct fwnode_handle fwnode;
  18         const struct software_node *node;
  19
  20         /* hierarchy */
  21         struct ida child_ids;
  22         struct list_head entry;
  23         struct list_head children;
  24         struct swnode *parent;
  25
  26         unsigned int allocated:1;
  27 };
  28
  29 static DEFINE_IDA(swnode_root_ids);
  30 static struct kset *swnode_kset;
  31
  32 #define kobj_to_swnode(_kobj_) container_of(_kobj_, struct swnode, kobj)
  33
  34 static const struct fwnode_operations software_node_ops;
  35
  36 bool is_software_node(const struct fwnode_handle *fwnode)
  37 {
  38         return !IS_ERR_OR_NULL(fwnode) && fwnode->ops == &software_node_ops;
  39 }
  40 EXPORT_SYMBOL_GPL(is_software_node);
  41
  42 #define to_swnode(__fwnode)                                             \
  43         ({                                                              \
  44                 typeof(__fwnode) __to_swnode_fwnode = __fwnode;         \
  45                                                                         \
  46                 is_software_node(__to_swnode_fwnode) ?                  \
  47                         container_of(__to_swnode_fwnode,                \
  48                                      struct swnode, fwnode) : NULL;     \
  49         })
  50
  51 static struct swnode *
  52 software_node_to_swnode(const struct software_node *node)
  53 {
  54         struct swnode *swnode = NULL;
  55         struct kobject *k;
  56
  57         if (!node)
  58                 return NULL;
  59
  60         spin_lock(&swnode_kset->list_lock);
  61
  62         list_for_each_entry(k, &swnode_kset->list, entry) {
  63                 swnode = kobj_to_swnode(k);
  64                 if (swnode->node == node)
  65                         break;
  66                 swnode = NULL;
  67         }
  68
  69         spin_unlock(&swnode_kset->list_lock);
  70
  71         return swnode;
  72 }
  73
  74 const struct software_node *to_software_node(const struct fwnode_handle *fwnode)
  75 {
  76         const struct swnode *swnode = to_swnode(fwnode);
  77
  78         return swnode ? swnode->node : NULL;
  79 }
  80 EXPORT_SYMBOL_GPL(to_software_node);
  81
  82 struct fwnode_handle *software_node_fwnode(const struct software_node *node)
  83 {
  84         struct swnode *swnode = software_node_to_swnode(node);
  85
  86         return swnode ? &swnode->fwnode : NULL;
  87 }
  88 EXPORT_SYMBOL_GPL(software_node_fwnode);
  89
  90 /* -------------------------------------------------------------------------- */
  91 /* property_entry processing */
  92
  93 static const struct property_entry *
  94 property_entry_get(const struct property_entry *prop, const char *name)
  95 {
  96         if (!prop)
  97                 return NULL;
  98
  99         for (; prop->name; prop++)
 100                 if (!strcmp(name, prop->name))
 101                         return prop;
 102
 103         return NULL;
 104 }
 105
 106 static const void *property_get_pointer(const struct property_entry *prop)
 107 {
 108         if (!prop->length)
 109                 return NULL;
 110
 111         if (prop->is_array)
 112                 return prop->pointer;
 113
 114         return &prop->value;
 115 }
 116
 117 static const void *property_entry_find(const struct property_entry *props,
 118                                        const char *propname, size_t length)
 119 {
 120         const struct property_entry *prop;
 121         const void *pointer;
 122
 123         prop = property_entry_get(props, propname);
 124         if (!prop)
 125                 return ERR_PTR(-EINVAL);
 126         pointer = property_get_pointer(prop);
 127         if (!pointer)
 128                 return ERR_PTR(-ENODATA);
 129         if (length > prop->length)
 130                 return ERR_PTR(-EOVERFLOW);
 131         return pointer;
 132 }
 133
 134 static int
 135 property_entry_count_elems_of_size(const struct property_entry *props,
 136                                    const char *propname, size_t length)
 137 {
 138         const struct property_entry *prop;
 139
 140         prop = property_entry_get(props, propname);
 141         if (!prop)
 142                 return -EINVAL;
 143
 144         return prop->length / length;
 145 }
 146
 147 static int property_entry_read_int_array(const struct property_entry *props,
 148                                          const char *name,
 149                                          unsigned int elem_size, void *val,
 150                                          size_t nval)
 151 {
 152         const void *pointer;
 153         size_t length;
 154
 155         if (!val)
 156                 return property_entry_count_elems_of_size(props, name,
 157                                                           elem_size);
 158
 159         if (!is_power_of_2(elem_size) || elem_size > sizeof(u64))
 160                 return -ENXIO;
 161
 162         length = nval * elem_size;
 163
 164         pointer = property_entry_find(props, name, length);
 165         if (IS_ERR(pointer))
 166                 return PTR_ERR(pointer);
 167
 168         memcpy(val, pointer, length);
 169         return 0;
 170 }
 171
 172 static int property_entry_read_string_array(const struct property_entry *props,
 173                                             const char *propname,
 174                                             const char **strings, size_t nval)
 175 {
 176         const void *pointer;
 177         size_t length;
 178         int array_len;
 179
 180         /* Find out the array length. */
 181         array_len = property_entry_count_elems_of_size(props, propname,
 182                                                        sizeof(const char *));
 183         if (array_len < 0)
 184                 return array_len;
 185
 186         /* Return how many there are if strings is NULL. */
 187         if (!strings)
 188                 return array_len;
 189
 190         array_len = min_t(size_t, nval, array_len);
 191         length = array_len * sizeof(*strings);
 192
 193         pointer = property_entry_find(props, propname, length);
 194         if (IS_ERR(pointer))
 195                 return PTR_ERR(pointer);
 196
 197         memcpy(strings, pointer, length);
 198
 199         return array_len;
 200 }
 201
 202 static void property_entry_free_data(const struct property_entry *p)
 203 {
 204         const void *pointer = property_get_pointer(p);
 205         const char * const *src_str;
 206         size_t i, nval;
 207
 208         if (p->is_array) {
 209                 if (p->type == DEV_PROP_STRING && p->pointer) {
 210                         src_str = p->pointer;
 211                         nval = p->length / sizeof(const char *);
 212                         for (i = 0; i < nval; i++)
 213                                 kfree(src_str[i]);
 214                 }
 215                 kfree(pointer);
 216         } else if (p->type == DEV_PROP_STRING) {
 217                 kfree(p->value.str);
 218         }
 219         kfree(p->name);
 220 }
 221
 222 static const char * const *
 223 property_copy_string_array(const struct property_entry *src)
 224 {
 225         const char **d;
 226         const char * const *src_str = src->pointer;
 227         size_t nval = src->length / sizeof(*d);
 228         int i;
 229
 230         d = kcalloc(nval, sizeof(*d), GFP_KERNEL);
 231         if (!d)
 232                 return NULL;
 233
 234         for (i = 0; i < nval; i++) {
 235                 d[i] = kstrdup(src_str[i], GFP_KERNEL);
 236                 if (!d[i] && src_str[i]) {
 237                         while (--i >= 0)
 238                                 kfree(d[i]);
 239                         kfree(d);
 240                         return NULL;
 241                 }
 242         }
 243
 244         return d;
 245 }
 246
 247 static int property_entry_copy_data(struct property_entry *dst,
 248                                     const struct property_entry *src)
 249 {
 250         const void *pointer = property_get_pointer(src);
 251         const void *new;
 252
 253         if (src->is_array) {
 254                 if (!src->length)
 255                         return -ENODATA;
 256
 257                 if (src->type == DEV_PROP_STRING) {
 258                         new = property_copy_string_array(src);
 259                         if (!new)
 260                                 return -ENOMEM;
 261                 } else {
 262                         new = kmemdup(pointer, src->length, GFP_KERNEL);
 263                         if (!new)
 264                                 return -ENOMEM;
 265                 }
 266
 267                 dst->is_array = true;
 268                 dst->pointer = new;
 269         } else if (src->type == DEV_PROP_STRING) {
 270                 new = kstrdup(src->value.str, GFP_KERNEL);
 271                 if (!new && src->value.str)
 272                         return -ENOMEM;
 273
 274                 dst->value.str = new;
 275         } else {
 276                 dst->value = src->value;
 277         }
 278
 279         dst->length = src->length;
 280         dst->type = src->type;
 281         dst->name = kstrdup(src->name, GFP_KERNEL);
 282         if (!dst->name)
 283                 goto out_free_data;
 284
 285         return 0;
 286
 287 out_free_data:
 288         property_entry_free_data(dst);
 289         return -ENOMEM;
 290 }
 291
 292 /**
 293  * property_entries_dup - duplicate array of properties
 294  * @properties: array of properties to copy
 295  *
 296  * This function creates a deep copy of the given NULL-terminated array
 297  * of property entries.
 298  */
 299 struct property_entry *
 300 property_entries_dup(const struct property_entry *properties)
 301 {
 302         struct property_entry *p;
 303         int i, n = 0;
 304         int ret;
 305
 306         if (!properties)
 307                 return NULL;
 308
 309         while (properties[n].name)
 310                 n++;
 311
 312         p = kcalloc(n + 1, sizeof(*p), GFP_KERNEL);
 313         if (!p)
 314                 return ERR_PTR(-ENOMEM);
 315
 316         for (i = 0; i < n; i++) {
 317                 ret = property_entry_copy_data(&p[i], &properties[i]);
 318                 if (ret) {
 319                         while (--i >= 0)
 320                                 property_entry_free_data(&p[i]);
 321                         kfree(p);
 322                         return ERR_PTR(ret);
 323                 }
 324         }
 325
 326         return p;
 327 }
 328 EXPORT_SYMBOL_GPL(property_entries_dup);
 329
 330 /**
 331  * property_entries_free - free previously allocated array of properties
 332  * @properties: array of properties to destroy
 333  *
 334  * This function frees given NULL-terminated array of property entries,
 335  * along with their data.
 336  */
 337 void property_entries_free(const struct property_entry *properties)
 338 {
 339         const struct property_entry *p;
 340
 341         if (!properties)
 342                 return;
 343
 344         for (p = properties; p->name; p++)
 345                 property_entry_free_data(p);
 346
 347         kfree(properties);
 348 }
 349 EXPORT_SYMBOL_GPL(property_entries_free);
 350
 351 /* -------------------------------------------------------------------------- */
 352 /* fwnode operations */
 353
 354 static struct fwnode_handle *software_node_get(struct fwnode_handle *fwnode)
 355 {
 356         struct swnode *swnode = to_swnode(fwnode);
 357
 358         kobject_get(&swnode->kobj);
 359
 360         return &swnode->fwnode;
 361 }
 362
 363 static void software_node_put(struct fwnode_handle *fwnode)
 364 {
 365         struct swnode *swnode = to_swnode(fwnode);
 366
 367         kobject_put(&swnode->kobj);
 368 }
 369
 370 static bool software_node_property_present(const struct fwnode_handle *fwnode,
 371                                            const char *propname)
 372 {
 373         struct swnode *swnode = to_swnode(fwnode);
 374
 375         return !!property_entry_get(swnode->node->properties, propname);
 376 }
 377
 378 static int software_node_read_int_array(const struct fwnode_handle *fwnode,
 379                                         const char *propname,
 380                                         unsigned int elem_size, void *val,
 381                                         size_t nval)
 382 {
 383         struct swnode *swnode = to_swnode(fwnode);
 384
 385         return property_entry_read_int_array(swnode->node->properties, propname,
 386                                              elem_size, val, nval);
 387 }
 388
 389 static int software_node_read_string_array(const struct fwnode_handle *fwnode,
 390                                            const char *propname,
 391                                            const char **val, size_t nval)
 392 {
 393         struct swnode *swnode = to_swnode(fwnode);
 394
 395         return property_entry_read_string_array(swnode->node->properties,
 396                                                 propname, val, nval);
 397 }
 398
 399 static const char *
 400 software_node_get_name(const struct fwnode_handle *fwnode)
 401 {
 402         const struct swnode *swnode = to_swnode(fwnode);
 403
 404         if (!swnode)
 405                 return "(null)";
 406
 407         return kobject_name(&swnode->kobj);
 408 }
 409
 410 static const char *
 411 software_node_get_name_prefix(const struct fwnode_handle *fwnode)
 412 {
 413         struct fwnode_handle *parent;
 414         const char *prefix;
 415
 416         parent = fwnode_get_parent(fwnode);
 417         if (!parent)
 418                 return "";
 419
 420         /* Figure out the prefix from the parents. */
 421         while (is_software_node(parent))
 422                 parent = fwnode_get_next_parent(parent);
 423
 424         prefix = fwnode_get_name_prefix(parent);
 425         fwnode_handle_put(parent);
 426
 427         /* Guess something if prefix was NULL. */
 428         return prefix ?: "/";
 429 }
 430
 431 static struct fwnode_handle *
 432 software_node_get_parent(const struct fwnode_handle *fwnode)
 433 {
 434         struct swnode *swnode = to_swnode(fwnode);
 435
 436         if (!swnode || !swnode->parent)
 437                 return NULL;
 438
 439         return fwnode_handle_get(&swnode->parent->fwnode);
 440 }
 441
 442 static struct fwnode_handle *
 443 software_node_get_next_child(const struct fwnode_handle *fwnode,
 444                              struct fwnode_handle *child)
 445 {
 446         struct swnode *p = to_swnode(fwnode);
 447         struct swnode *c = to_swnode(child);
 448
 449         if (!p || list_empty(&p->children) ||
 450             (c && list_is_last(&c->entry, &p->children)))
 451                 return NULL;
 452
 453         if (c)
 454                 c = list_next_entry(c, entry);
 455         else
 456                 c = list_first_entry(&p->children, struct swnode, entry);
 457         return &c->fwnode;
 458 }
 459
 460 static struct fwnode_handle *
 461 software_node_get_named_child_node(const struct fwnode_handle *fwnode,
 462                                    const char *childname)
 463 {
 464         struct swnode *swnode = to_swnode(fwnode);
 465         struct swnode *child;
 466
 467         if (!swnode || list_empty(&swnode->children))
 468                 return NULL;
 469
 470         list_for_each_entry(child, &swnode->children, entry) {
 471                 if (!strcmp(childname, kobject_name(&child->kobj))) {
 472                         kobject_get(&child->kobj);
 473                         return &child->fwnode;
 474                 }
 475         }
 476         return NULL;
 477 }
 478
 479 static int
 480 software_node_get_reference_args(const struct fwnode_handle *fwnode,
 481                                  const char *propname, const char *nargs_prop,
 482                                  unsigned int nargs, unsigned int index,
 483                                  struct fwnode_reference_args *args)
 484 {
 485         struct swnode *swnode = to_swnode(fwnode);
 486         const struct software_node_reference *ref;
 487         const struct property_entry *prop;
 488         struct fwnode_handle *refnode;
 489         int i;
 490
 491         if (!swnode || !swnode->node->references)
 492                 return -ENOENT;
 493
 494         for (ref = swnode->node->references; ref->name; ref++)
 495                 if (!strcmp(ref->name, propname))
 496                         break;
 497
 498         if (!ref->name || index > (ref->nrefs - 1))
 499                 return -ENOENT;
 500
 501         refnode = software_node_fwnode(ref->refs[index].node);
 502         if (!refnode)
 503                 return -ENOENT;
 504
 505         if (nargs_prop) {
 506                 prop = property_entry_get(swnode->node->properties, nargs_prop);
 507                 if (!prop)
 508                         return -EINVAL;
 509
 510                 nargs = prop->value.u32_data;
 511         }
 512
 513         if (nargs > NR_FWNODE_REFERENCE_ARGS)
 514                 return -EINVAL;
 515
 516         args->fwnode = software_node_get(refnode);
 517         args->nargs = nargs;
 518
 519         for (i = 0; i < nargs; i++)
 520                 args->args[i] = ref->refs[index].args[i];
 521
 522         return 0;
 523 }
 524
 525 static const struct fwnode_operations software_node_ops = {
 526         .get = software_node_get,
 527         .put = software_node_put,
 528         .property_present = software_node_property_present,
 529         .property_read_int_array = software_node_read_int_array,
 530         .property_read_string_array = software_node_read_string_array,
 531         .get_name = software_node_get_name,
 532         .get_name_prefix = software_node_get_name_prefix,
 533         .get_parent = software_node_get_parent,
 534         .get_next_child_node = software_node_get_next_child,
 535         .get_named_child_node = software_node_get_named_child_node,
 536         .get_reference_args = software_node_get_reference_args
 537 };
 538
 539 /* -------------------------------------------------------------------------- */
 540
 541 /**
 542  * software_node_find_by_name - Find software node by name
 543  * @parent: Parent of the software node
 544  * @name: Name of the software node
 545  *
 546  * The function will find a node that is child of @parent and that is named
 547  * @name. If no node is found, the function returns NULL.
 548  *
 549  * NOTE: you will need to drop the reference with fwnode_handle_put() after use.
 550  */
 551 const struct software_node *
 552 software_node_find_by_name(const struct software_node *parent, const char *name)
 553 {
 554         struct swnode *swnode = NULL;
 555         struct kobject *k;
 556
 557         if (!name)
 558                 return NULL;
 559
 560         spin_lock(&swnode_kset->list_lock);
 561
 562         list_for_each_entry(k, &swnode_kset->list, entry) {
 563                 swnode = kobj_to_swnode(k);
 564                 if (parent == swnode->node->parent && swnode->node->name &&
 565                     !strcmp(name, swnode->node->name)) {
 566                         kobject_get(&swnode->kobj);
 567                         break;
 568                 }
 569                 swnode = NULL;
 570         }
 571
 572         spin_unlock(&swnode_kset->list_lock);
 573
 574         return swnode ? swnode->node : NULL;
 575 }
 576 EXPORT_SYMBOL_GPL(software_node_find_by_name);
 577
 578 static int
 579 software_node_register_properties(struct software_node *node,
 580                                   const struct property_entry *properties)
 581 {
 582         struct property_entry *props;
 583
 584         props = property_entries_dup(properties);
 585         if (IS_ERR(props))
 586                 return PTR_ERR(props);
 587
 588         node->properties = props;
 589
 590         return 0;
 591 }
 592
 593 static void software_node_release(struct kobject *kobj)
 594 {
 595         struct swnode *swnode = kobj_to_swnode(kobj);
 596
 597         if (swnode->allocated) {
 598                 property_entries_free(swnode->node->properties);
 599                 kfree(swnode->node);
 600         }
 601         ida_destroy(&swnode->child_ids);
 602         kfree(swnode);
 603 }
 604
 605 static struct kobj_type software_node_type = {
 606         .release = software_node_release,
 607         .sysfs_ops = &kobj_sysfs_ops,
 608 };
 609
 610 static struct fwnode_handle *
 611 swnode_register(const struct software_node *node, struct swnode *parent,
 612                 unsigned int allocated)
 613 {
 614         struct swnode *swnode;
 615         int ret;
 616
 617         swnode = kzalloc(sizeof(*swnode), GFP_KERNEL);
 618         if (!swnode) {
 619                 ret = -ENOMEM;
 620                 goto out_err;
 621         }
 622
 623         ret = ida_simple_get(parent ? &parent->child_ids : &swnode_root_ids,
 624                              0, 0, GFP_KERNEL);
 625         if (ret < 0) {
 626                 kfree(swnode);
 627                 goto out_err;
 628         }
 629
 630         swnode->id = ret;
 631         swnode->node = node;
 632         swnode->parent = parent;
 633         swnode->allocated = allocated;
 634         swnode->kobj.kset = swnode_kset;
 635         swnode->fwnode.ops = &software_node_ops;
 636
 637         ida_init(&swnode->child_ids);
 638         INIT_LIST_HEAD(&swnode->entry);
 639         INIT_LIST_HEAD(&swnode->children);
 640
 641         if (node->name)
 642                 ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
 643                                            parent ? &parent->kobj : NULL,
 644                                            "%s", node->name);
 645         else
 646                 ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
 647                                            parent ? &parent->kobj : NULL,
 648                                            "node%d", swnode->id);
 649         if (ret) {
 650                 kobject_put(&swnode->kobj);
 651                 return ERR_PTR(ret);
 652         }
 653
 654         if (parent)
 655                 list_add_tail(&swnode->entry, &parent->children);
 656
 657         kobject_uevent(&swnode->kobj, KOBJ_ADD);
 658         return &swnode->fwnode;
 659
 660 out_err:
 661         if (allocated)
 662                 property_entries_free(node->properties);
 663         return ERR_PTR(ret);
 664 }
 665
 666 /**
 667  * software_node_register_nodes - Register an array of software nodes
 668  * @nodes: Zero terminated array of software nodes to be registered
 669  *
 670  * Register multiple software nodes at once.
 671  */
 672 int software_node_register_nodes(const struct software_node *nodes)
 673 {
 674         int ret;
 675         int i;
 676
 677         for (i = 0; nodes[i].name; i++) {
 678                 ret = software_node_register(&nodes[i]);
 679                 if (ret) {
 680                         software_node_unregister_nodes(nodes);
 681                         return ret;
 682                 }
 683         }
 684
 685         return 0;
 686 }
 687 EXPORT_SYMBOL_GPL(software_node_register_nodes);
 688
 689 /**
 690  * software_node_unregister_nodes - Unregister an array of software nodes
 691  * @nodes: Zero terminated array of software nodes to be unregistered
 692  *
 693  * Unregister multiple software nodes at once.
 694  */
 695 void software_node_unregister_nodes(const struct software_node *nodes)
 696 {
 697         struct swnode *swnode;
 698         int i;
 699
 700         for (i = 0; nodes[i].name; i++) {
 701                 swnode = software_node_to_swnode(&nodes[i]);
 702                 if (swnode)
 703                         fwnode_remove_software_node(&swnode->fwnode);
 704         }
 705 }
 706 EXPORT_SYMBOL_GPL(software_node_unregister_nodes);
 707
 708 /**
 709  * software_node_register - Register static software node
 710  * @node: The software node to be registered
 711  */
 712 int software_node_register(const struct software_node *node)
 713 {
 714         struct swnode *parent = software_node_to_swnode(node->parent);
 715
 716         if (software_node_to_swnode(node))
 717                 return -EEXIST;
 718
 719         return PTR_ERR_OR_ZERO(swnode_register(node, parent, 0));
 720 }
 721 EXPORT_SYMBOL_GPL(software_node_register);
 722
 723 struct fwnode_handle *
 724 fwnode_create_software_node(const struct property_entry *properties,
 725                             const struct fwnode_handle *parent)
 726 {
 727         struct software_node *node;
 728         struct swnode *p = NULL;
 729         int ret;
 730
 731         if (parent) {
 732                 if (IS_ERR(parent))
 733                         return ERR_CAST(parent);
 734                 if (!is_software_node(parent))
 735                         return ERR_PTR(-EINVAL);
 736                 p = to_swnode(parent);
 737         }
 738
 739         node = kzalloc(sizeof(*node), GFP_KERNEL);
 740         if (!node)
 741                 return ERR_PTR(-ENOMEM);
 742
 743         ret = software_node_register_properties(node, properties);
 744         if (ret) {
 745                 kfree(node);
 746                 return ERR_PTR(ret);
 747         }
 748
 749         node->parent = p ? p->node : NULL;
 750
 751         return swnode_register(node, p, 1);
 752 }
 753 EXPORT_SYMBOL_GPL(fwnode_create_software_node);
 754
 755 void fwnode_remove_software_node(struct fwnode_handle *fwnode)
 756 {
 757         struct swnode *swnode = to_swnode(fwnode);
 758
 759         if (!swnode)
 760                 return;
 761
 762         if (swnode->parent) {
 763                 ida_simple_remove(&swnode->parent->child_ids, swnode->id);
 764                 list_del(&swnode->entry);
 765         } else {
 766                 ida_simple_remove(&swnode_root_ids, swnode->id);
 767         }
 768
 769         kobject_put(&swnode->kobj);
 770 }
 771 EXPORT_SYMBOL_GPL(fwnode_remove_software_node);
 772
 773 int software_node_notify(struct device *dev, unsigned long action)
 774 {
 775         struct fwnode_handle *fwnode = dev_fwnode(dev);
 776         struct swnode *swnode;
 777         int ret;
 778
 779         if (!fwnode)
 780                 return 0;
 781
 782         if (!is_software_node(fwnode))
 783                 fwnode = fwnode->secondary;
 784         if (!is_software_node(fwnode))
 785                 return 0;
 786
 787         swnode = to_swnode(fwnode);
 788
 789         switch (action) {
 790         case KOBJ_ADD:
 791                 ret = sysfs_create_link(&dev->kobj, &swnode->kobj,
 792                                         "software_node");
 793                 if (ret)
 794                         break;
 795
 796                 ret = sysfs_create_link(&swnode->kobj, &dev->kobj,
 797                                         dev_name(dev));
 798                 if (ret) {
 799                         sysfs_remove_link(&dev->kobj, "software_node");
 800                         break;
 801                 }
 802                 kobject_get(&swnode->kobj);
 803                 break;
 804         case KOBJ_REMOVE:
 805                 sysfs_remove_link(&swnode->kobj, dev_name(dev));
 806                 sysfs_remove_link(&dev->kobj, "software_node");
 807                 kobject_put(&swnode->kobj);
 808                 break;
 809         default:
 810                 break;
 811         }
 812
 813         return 0;
 814 }
 815
 816 static int __init software_node_init(void)
 817 {
 818         swnode_kset = kset_create_and_add("software_nodes", NULL, kernel_kobj);
 819         if (!swnode_kset)
 820                 return -ENOMEM;
 821         return 0;
 822 }
 823 postcore_initcall(software_node_init);
 824
 825 static void __exit software_node_exit(void)
 826 {
 827         ida_destroy(&swnode_root_ids);
 828         kset_unregister(swnode_kset);
 829 }
 830 __exitcall(software_node_exit);