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         return prop->is_inline ? &prop->value : prop->pointer;
 112 }
 113
 114 static const void *property_entry_find(const struct property_entry *props,
 115                                        const char *propname, size_t length)
 116 {
 117         const struct property_entry *prop;
 118         const void *pointer;
 119
 120         prop = property_entry_get(props, propname);
 121         if (!prop)
 122                 return ERR_PTR(-EINVAL);
 123         pointer = property_get_pointer(prop);
 124         if (!pointer)
 125                 return ERR_PTR(-ENODATA);
 126         if (length > prop->length)
 127                 return ERR_PTR(-EOVERFLOW);
 128         return pointer;
 129 }
 130
 131 static int
 132 property_entry_count_elems_of_size(const struct property_entry *props,
 133                                    const char *propname, size_t length)
 134 {
 135         const struct property_entry *prop;
 136
 137         prop = property_entry_get(props, propname);
 138         if (!prop)
 139                 return -EINVAL;
 140
 141         return prop->length / length;
 142 }
 143
 144 static int property_entry_read_int_array(const struct property_entry *props,
 145                                          const char *name,
 146                                          unsigned int elem_size, void *val,
 147                                          size_t nval)
 148 {
 149         const void *pointer;
 150         size_t length;
 151
 152         if (!val)
 153                 return property_entry_count_elems_of_size(props, name,
 154                                                           elem_size);
 155
 156         if (!is_power_of_2(elem_size) || elem_size > sizeof(u64))
 157                 return -ENXIO;
 158
 159         length = nval * elem_size;
 160
 161         pointer = property_entry_find(props, name, length);
 162         if (IS_ERR(pointer))
 163                 return PTR_ERR(pointer);
 164
 165         memcpy(val, pointer, length);
 166         return 0;
 167 }
 168
 169 static int property_entry_read_string_array(const struct property_entry *props,
 170                                             const char *propname,
 171                                             const char **strings, size_t nval)
 172 {
 173         const void *pointer;
 174         size_t length;
 175         int array_len;
 176
 177         /* Find out the array length. */
 178         array_len = property_entry_count_elems_of_size(props, propname,
 179                                                        sizeof(const char *));
 180         if (array_len < 0)
 181                 return array_len;
 182
 183         /* Return how many there are if strings is NULL. */
 184         if (!strings)
 185                 return array_len;
 186
 187         array_len = min_t(size_t, nval, array_len);
 188         length = array_len * sizeof(*strings);
 189
 190         pointer = property_entry_find(props, propname, length);
 191         if (IS_ERR(pointer))
 192                 return PTR_ERR(pointer);
 193
 194         memcpy(strings, pointer, length);
 195
 196         return array_len;
 197 }
 198
 199 static void property_entry_free_data(const struct property_entry *p)
 200 {
 201         const char * const *src_str;
 202         size_t i, nval;
 203
 204         if (p->type == DEV_PROP_STRING) {
 205                 src_str = property_get_pointer(p);
 206                 nval = p->length / sizeof(*src_str);
 207                 for (i = 0; i < nval; i++)
 208                         kfree(src_str[i]);
 209         }
 210
 211         if (!p->is_inline)
 212                 kfree(p->pointer);
 213
 214         kfree(p->name);
 215 }
 216
 217 static bool property_copy_string_array(const char **dst_ptr,
 218                                        const char * const *src_ptr,
 219                                        size_t nval)
 220 {
 221         int i;
 222
 223         for (i = 0; i < nval; i++) {
 224                 dst_ptr[i] = kstrdup(src_ptr[i], GFP_KERNEL);
 225                 if (!dst_ptr[i] && src_ptr[i]) {
 226                         while (--i >= 0)
 227                                 kfree(dst_ptr[i]);
 228                         return false;
 229                 }
 230         }
 231
 232         return true;
 233 }
 234
 235 static int property_entry_copy_data(struct property_entry *dst,
 236                                     const struct property_entry *src)
 237 {
 238         const void *pointer = property_get_pointer(src);
 239         void *dst_ptr;
 240         size_t nval;
 241
 242         /*
 243          * Properties with no data should not be marked as stored
 244          * out of line.
 245          */
 246         if (!src->is_inline && !src->length)
 247                 return -ENODATA;
 248
 249         /*
 250          * Reference properties are never stored inline as
 251          * they are too big.
 252          */
 253         if (src->type == DEV_PROP_REF && src->is_inline)
 254                 return -EINVAL;
 255
 256         if (src->length <= sizeof(dst->value)) {
 257                 dst_ptr = &dst->value;
 258                 dst->is_inline = true;
 259         } else {
 260                 dst_ptr = kmalloc(src->length, GFP_KERNEL);
 261                 if (!dst_ptr)
 262                         return -ENOMEM;
 263                 dst->pointer = dst_ptr;
 264         }
 265
 266         if (src->type == DEV_PROP_STRING) {
 267                 nval = src->length / sizeof(const char *);
 268                 if (!property_copy_string_array(dst_ptr, pointer, nval)) {
 269                         if (!dst->is_inline)
 270                                 kfree(dst->pointer);
 271                         return -ENOMEM;
 272                 }
 273         } else {
 274                 memcpy(dst_ptr, pointer, src->length);
 275         }
 276
 277         dst->length = src->length;
 278         dst->type = src->type;
 279         dst->name = kstrdup(src->name, GFP_KERNEL);
 280         if (!dst->name) {
 281                 property_entry_free_data(dst);
 282                 return -ENOMEM;
 283         }
 284
 285         return 0;
 286 }
 287
 288 /**
 289  * property_entries_dup - duplicate array of properties
 290  * @properties: array of properties to copy
 291  *
 292  * This function creates a deep copy of the given NULL-terminated array
 293  * of property entries.
 294  */
 295 struct property_entry *
 296 property_entries_dup(const struct property_entry *properties)
 297 {
 298         struct property_entry *p;
 299         int i, n = 0;
 300         int ret;
 301
 302         if (!properties)
 303                 return NULL;
 304
 305         while (properties[n].name)
 306                 n++;
 307
 308         p = kcalloc(n + 1, sizeof(*p), GFP_KERNEL);
 309         if (!p)
 310                 return ERR_PTR(-ENOMEM);
 311
 312         for (i = 0; i < n; i++) {
 313                 ret = property_entry_copy_data(&p[i], &properties[i]);
 314                 if (ret) {
 315                         while (--i >= 0)
 316                                 property_entry_free_data(&p[i]);
 317                         kfree(p);
 318                         return ERR_PTR(ret);
 319                 }
 320         }
 321
 322         return p;
 323 }
 324 EXPORT_SYMBOL_GPL(property_entries_dup);
 325
 326 /**
 327  * property_entries_free - free previously allocated array of properties
 328  * @properties: array of properties to destroy
 329  *
 330  * This function frees given NULL-terminated array of property entries,
 331  * along with their data.
 332  */
 333 void property_entries_free(const struct property_entry *properties)
 334 {
 335         const struct property_entry *p;
 336
 337         if (!properties)
 338                 return;
 339
 340         for (p = properties; p->name; p++)
 341                 property_entry_free_data(p);
 342
 343         kfree(properties);
 344 }
 345 EXPORT_SYMBOL_GPL(property_entries_free);
 346
 347 /* -------------------------------------------------------------------------- */
 348 /* fwnode operations */
 349
 350 static struct fwnode_handle *software_node_get(struct fwnode_handle *fwnode)
 351 {
 352         struct swnode *swnode = to_swnode(fwnode);
 353
 354         kobject_get(&swnode->kobj);
 355
 356         return &swnode->fwnode;
 357 }
 358
 359 static void software_node_put(struct fwnode_handle *fwnode)
 360 {
 361         struct swnode *swnode = to_swnode(fwnode);
 362
 363         kobject_put(&swnode->kobj);
 364 }
 365
 366 static bool software_node_property_present(const struct fwnode_handle *fwnode,
 367                                            const char *propname)
 368 {
 369         struct swnode *swnode = to_swnode(fwnode);
 370
 371         return !!property_entry_get(swnode->node->properties, propname);
 372 }
 373
 374 static int software_node_read_int_array(const struct fwnode_handle *fwnode,
 375                                         const char *propname,
 376                                         unsigned int elem_size, void *val,
 377                                         size_t nval)
 378 {
 379         struct swnode *swnode = to_swnode(fwnode);
 380
 381         return property_entry_read_int_array(swnode->node->properties, propname,
 382                                              elem_size, val, nval);
 383 }
 384
 385 static int software_node_read_string_array(const struct fwnode_handle *fwnode,
 386                                            const char *propname,
 387                                            const char **val, size_t nval)
 388 {
 389         struct swnode *swnode = to_swnode(fwnode);
 390
 391         return property_entry_read_string_array(swnode->node->properties,
 392                                                 propname, val, nval);
 393 }
 394
 395 static const char *
 396 software_node_get_name(const struct fwnode_handle *fwnode)
 397 {
 398         const struct swnode *swnode = to_swnode(fwnode);
 399
 400         if (!swnode)
 401                 return "(null)";
 402
 403         return kobject_name(&swnode->kobj);
 404 }
 405
 406 static const char *
 407 software_node_get_name_prefix(const struct fwnode_handle *fwnode)
 408 {
 409         struct fwnode_handle *parent;
 410         const char *prefix;
 411
 412         parent = fwnode_get_parent(fwnode);
 413         if (!parent)
 414                 return "";
 415
 416         /* Figure out the prefix from the parents. */
 417         while (is_software_node(parent))
 418                 parent = fwnode_get_next_parent(parent);
 419
 420         prefix = fwnode_get_name_prefix(parent);
 421         fwnode_handle_put(parent);
 422
 423         /* Guess something if prefix was NULL. */
 424         return prefix ?: "/";
 425 }
 426
 427 static struct fwnode_handle *
 428 software_node_get_parent(const struct fwnode_handle *fwnode)
 429 {
 430         struct swnode *swnode = to_swnode(fwnode);
 431
 432         if (!swnode || !swnode->parent)
 433                 return NULL;
 434
 435         return fwnode_handle_get(&swnode->parent->fwnode);
 436 }
 437
 438 static struct fwnode_handle *
 439 software_node_get_next_child(const struct fwnode_handle *fwnode,
 440                              struct fwnode_handle *child)
 441 {
 442         struct swnode *p = to_swnode(fwnode);
 443         struct swnode *c = to_swnode(child);
 444
 445         if (!p || list_empty(&p->children) ||
 446             (c && list_is_last(&c->entry, &p->children)))
 447                 return NULL;
 448
 449         if (c)
 450                 c = list_next_entry(c, entry);
 451         else
 452                 c = list_first_entry(&p->children, struct swnode, entry);
 453         return &c->fwnode;
 454 }
 455
 456 static struct fwnode_handle *
 457 software_node_get_named_child_node(const struct fwnode_handle *fwnode,
 458                                    const char *childname)
 459 {
 460         struct swnode *swnode = to_swnode(fwnode);
 461         struct swnode *child;
 462
 463         if (!swnode || list_empty(&swnode->children))
 464                 return NULL;
 465
 466         list_for_each_entry(child, &swnode->children, entry) {
 467                 if (!strcmp(childname, kobject_name(&child->kobj))) {
 468                         kobject_get(&child->kobj);
 469                         return &child->fwnode;
 470                 }
 471         }
 472         return NULL;
 473 }
 474
 475 static int
 476 software_node_get_reference_args(const struct fwnode_handle *fwnode,
 477                                  const char *propname, const char *nargs_prop,
 478                                  unsigned int nargs, unsigned int index,
 479                                  struct fwnode_reference_args *args)
 480 {
 481         struct swnode *swnode = to_swnode(fwnode);
 482         const struct software_node_ref_args *ref_array;
 483         const struct software_node_ref_args *ref;
 484         const struct property_entry *prop;
 485         struct fwnode_handle *refnode;
 486         u32 nargs_prop_val;
 487         int error;
 488         int i;
 489
 490         if (!swnode)
 491                 return -ENOENT;
 492
 493         prop = property_entry_get(swnode->node->properties, propname);
 494         if (!prop)
 495                 return -ENOENT;
 496
 497         if (prop->type != DEV_PROP_REF)
 498                 return -EINVAL;
 499
 500         /*
 501          * We expect that references are never stored inline, even
 502          * single ones, as they are too big.
 503          */
 504         if (prop->is_inline)
 505                 return -EINVAL;
 506
 507         if (index * sizeof(*ref) >= prop->length)
 508                 return -ENOENT;
 509
 510         ref_array = prop->pointer;
 511         ref = &ref_array[index];
 512
 513         refnode = software_node_fwnode(ref->node);
 514         if (!refnode)
 515                 return -ENOENT;
 516
 517         if (nargs_prop) {
 518                 error = property_entry_read_int_array(swnode->node->properties,
 519                                                       nargs_prop, sizeof(u32),
 520                                                       &nargs_prop_val, 1);
 521                 if (error)
 522                         return error;
 523
 524                 nargs = nargs_prop_val;
 525         }
 526
 527         if (nargs > NR_FWNODE_REFERENCE_ARGS)
 528                 return -EINVAL;
 529
 530         args->fwnode = software_node_get(refnode);
 531         args->nargs = nargs;
 532
 533         for (i = 0; i < nargs; i++)
 534                 args->args[i] = ref->args[i];
 535
 536         return 0;
 537 }
 538
 539 static const struct fwnode_operations software_node_ops = {
 540         .get = software_node_get,
 541         .put = software_node_put,
 542         .property_present = software_node_property_present,
 543         .property_read_int_array = software_node_read_int_array,
 544         .property_read_string_array = software_node_read_string_array,
 545         .get_name = software_node_get_name,
 546         .get_name_prefix = software_node_get_name_prefix,
 547         .get_parent = software_node_get_parent,
 548         .get_next_child_node = software_node_get_next_child,
 549         .get_named_child_node = software_node_get_named_child_node,
 550         .get_reference_args = software_node_get_reference_args
 551 };
 552
 553 /* -------------------------------------------------------------------------- */
 554
 555 /**
 556  * software_node_find_by_name - Find software node by name
 557  * @parent: Parent of the software node
 558  * @name: Name of the software node
 559  *
 560  * The function will find a node that is child of @parent and that is named
 561  * @name. If no node is found, the function returns NULL.
 562  *
 563  * NOTE: you will need to drop the reference with fwnode_handle_put() after use.
 564  */
 565 const struct software_node *
 566 software_node_find_by_name(const struct software_node *parent, const char *name)
 567 {
 568         struct swnode *swnode = NULL;
 569         struct kobject *k;
 570
 571         if (!name)
 572                 return NULL;
 573
 574         spin_lock(&swnode_kset->list_lock);
 575
 576         list_for_each_entry(k, &swnode_kset->list, entry) {
 577                 swnode = kobj_to_swnode(k);
 578                 if (parent == swnode->node->parent && swnode->node->name &&
 579                     !strcmp(name, swnode->node->name)) {
 580                         kobject_get(&swnode->kobj);
 581                         break;
 582                 }
 583                 swnode = NULL;
 584         }
 585
 586         spin_unlock(&swnode_kset->list_lock);
 587
 588         return swnode ? swnode->node : NULL;
 589 }
 590 EXPORT_SYMBOL_GPL(software_node_find_by_name);
 591
 592 static int
 593 software_node_register_properties(struct software_node *node,
 594                                   const struct property_entry *properties)
 595 {
 596         struct property_entry *props;
 597
 598         props = property_entries_dup(properties);
 599         if (IS_ERR(props))
 600                 return PTR_ERR(props);
 601
 602         node->properties = props;
 603
 604         return 0;
 605 }
 606
 607 static void software_node_release(struct kobject *kobj)
 608 {
 609         struct swnode *swnode = kobj_to_swnode(kobj);
 610
 611         if (swnode->allocated) {
 612                 property_entries_free(swnode->node->properties);
 613                 kfree(swnode->node);
 614         }
 615         ida_destroy(&swnode->child_ids);
 616         kfree(swnode);
 617 }
 618
 619 static struct kobj_type software_node_type = {
 620         .release = software_node_release,
 621         .sysfs_ops = &kobj_sysfs_ops,
 622 };
 623
 624 static struct fwnode_handle *
 625 swnode_register(const struct software_node *node, struct swnode *parent,
 626                 unsigned int allocated)
 627 {
 628         struct swnode *swnode;
 629         int ret;
 630
 631         swnode = kzalloc(sizeof(*swnode), GFP_KERNEL);
 632         if (!swnode) {
 633                 ret = -ENOMEM;
 634                 goto out_err;
 635         }
 636
 637         ret = ida_simple_get(parent ? &parent->child_ids : &swnode_root_ids,
 638                              0, 0, GFP_KERNEL);
 639         if (ret < 0) {
 640                 kfree(swnode);
 641                 goto out_err;
 642         }
 643
 644         swnode->id = ret;
 645         swnode->node = node;
 646         swnode->parent = parent;
 647         swnode->allocated = allocated;
 648         swnode->kobj.kset = swnode_kset;
 649         swnode->fwnode.ops = &software_node_ops;
 650
 651         ida_init(&swnode->child_ids);
 652         INIT_LIST_HEAD(&swnode->entry);
 653         INIT_LIST_HEAD(&swnode->children);
 654
 655         if (node->name)
 656                 ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
 657                                            parent ? &parent->kobj : NULL,
 658                                            "%s", node->name);
 659         else
 660                 ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
 661                                            parent ? &parent->kobj : NULL,
 662                                            "node%d", swnode->id);
 663         if (ret) {
 664                 kobject_put(&swnode->kobj);
 665                 return ERR_PTR(ret);
 666         }
 667
 668         if (parent)
 669                 list_add_tail(&swnode->entry, &parent->children);
 670
 671         kobject_uevent(&swnode->kobj, KOBJ_ADD);
 672         return &swnode->fwnode;
 673
 674 out_err:
 675         if (allocated)
 676                 property_entries_free(node->properties);
 677         return ERR_PTR(ret);
 678 }
 679
 680 /**
 681  * software_node_register_nodes - Register an array of software nodes
 682  * @nodes: Zero terminated array of software nodes to be registered
 683  *
 684  * Register multiple software nodes at once.
 685  */
 686 int software_node_register_nodes(const struct software_node *nodes)
 687 {
 688         int ret;
 689         int i;
 690
 691         for (i = 0; nodes[i].name; i++) {
 692                 ret = software_node_register(&nodes[i]);
 693                 if (ret) {
 694                         software_node_unregister_nodes(nodes);
 695                         return ret;
 696                 }
 697         }
 698
 699         return 0;
 700 }
 701 EXPORT_SYMBOL_GPL(software_node_register_nodes);
 702
 703 /**
 704  * software_node_unregister_nodes - Unregister an array of software nodes
 705  * @nodes: Zero terminated array of software nodes to be unregistered
 706  *
 707  * Unregister multiple software nodes at once.
 708  */
 709 void software_node_unregister_nodes(const struct software_node *nodes)
 710 {
 711         struct swnode *swnode;
 712         int i;
 713
 714         for (i = 0; nodes[i].name; i++) {
 715                 swnode = software_node_to_swnode(&nodes[i]);
 716                 if (swnode)
 717                         fwnode_remove_software_node(&swnode->fwnode);
 718         }
 719 }
 720 EXPORT_SYMBOL_GPL(software_node_unregister_nodes);
 721
 722 /**
 723  * software_node_register - Register static software node
 724  * @node: The software node to be registered
 725  */
 726 int software_node_register(const struct software_node *node)
 727 {
 728         struct swnode *parent = software_node_to_swnode(node->parent);
 729
 730         if (software_node_to_swnode(node))
 731                 return -EEXIST;
 732
 733         return PTR_ERR_OR_ZERO(swnode_register(node, parent, 0));
 734 }
 735 EXPORT_SYMBOL_GPL(software_node_register);
 736
 737 struct fwnode_handle *
 738 fwnode_create_software_node(const struct property_entry *properties,
 739                             const struct fwnode_handle *parent)
 740 {
 741         struct software_node *node;
 742         struct swnode *p = NULL;
 743         int ret;
 744
 745         if (parent) {
 746                 if (IS_ERR(parent))
 747                         return ERR_CAST(parent);
 748                 if (!is_software_node(parent))
 749                         return ERR_PTR(-EINVAL);
 750                 p = to_swnode(parent);
 751         }
 752
 753         node = kzalloc(sizeof(*node), GFP_KERNEL);
 754         if (!node)
 755                 return ERR_PTR(-ENOMEM);
 756
 757         ret = software_node_register_properties(node, properties);
 758         if (ret) {
 759                 kfree(node);
 760                 return ERR_PTR(ret);
 761         }
 762
 763         node->parent = p ? p->node : NULL;
 764
 765         return swnode_register(node, p, 1);
 766 }
 767 EXPORT_SYMBOL_GPL(fwnode_create_software_node);
 768
 769 void fwnode_remove_software_node(struct fwnode_handle *fwnode)
 770 {
 771         struct swnode *swnode = to_swnode(fwnode);
 772
 773         if (!swnode)
 774                 return;
 775
 776         if (swnode->parent) {
 777                 ida_simple_remove(&swnode->parent->child_ids, swnode->id);
 778                 list_del(&swnode->entry);
 779         } else {
 780                 ida_simple_remove(&swnode_root_ids, swnode->id);
 781         }
 782
 783         kobject_put(&swnode->kobj);
 784 }
 785 EXPORT_SYMBOL_GPL(fwnode_remove_software_node);
 786
 787 int software_node_notify(struct device *dev, unsigned long action)
 788 {
 789         struct fwnode_handle *fwnode = dev_fwnode(dev);
 790         struct swnode *swnode;
 791         int ret;
 792
 793         if (!fwnode)
 794                 return 0;
 795
 796         if (!is_software_node(fwnode))
 797                 fwnode = fwnode->secondary;
 798         if (!is_software_node(fwnode))
 799                 return 0;
 800
 801         swnode = to_swnode(fwnode);
 802
 803         switch (action) {
 804         case KOBJ_ADD:
 805                 ret = sysfs_create_link(&dev->kobj, &swnode->kobj,
 806                                         "software_node");
 807                 if (ret)
 808                         break;
 809
 810                 ret = sysfs_create_link(&swnode->kobj, &dev->kobj,
 811                                         dev_name(dev));
 812                 if (ret) {
 813                         sysfs_remove_link(&dev->kobj, "software_node");
 814                         break;
 815                 }
 816                 kobject_get(&swnode->kobj);
 817                 break;
 818         case KOBJ_REMOVE:
 819                 sysfs_remove_link(&swnode->kobj, dev_name(dev));
 820                 sysfs_remove_link(&dev->kobj, "software_node");
 821                 kobject_put(&swnode->kobj);
 822                 break;
 823         default:
 824                 break;
 825         }
 826
 827         return 0;
 828 }
 829
 830 static int __init software_node_init(void)
 831 {
 832         swnode_kset = kset_create_and_add("software_nodes", NULL, kernel_kobj);
 833         if (!swnode_kset)
 834                 return -ENOMEM;
 835         return 0;
 836 }
 837 postcore_initcall(software_node_init);
 838
 839 static void __exit software_node_exit(void)
 840 {
 841         ida_destroy(&swnode_root_ids);
 842         kset_unregister(swnode_kset);
 843 }
 844 __exitcall(software_node_exit);