drivers/of/dynamic.c

   1 /*
   2  * Support for dynamic device trees.
   3  *
   4  * On some platforms, the device tree can be manipulated at runtime.
   5  * The routines in this section support adding, removing and changing
   6  * device tree nodes.
   7  */
   8
   9 #define pr_fmt(fmt)     "OF: " fmt
  10
  11 #include <linux/of.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/proc_fs.h>
  16
  17 #include "of_private.h"
  18
  19 /**
  20  * of_node_get() - Increment refcount of a node
  21  * @node:       Node to inc refcount, NULL is supported to simplify writing of
  22  *              callers
  23  *
  24  * Returns node.
  25  */
  26 struct device_node *of_node_get(struct device_node *node)
  27 {
  28         if (node)
  29                 kobject_get(&node->kobj);
  30         return node;
  31 }
  32 EXPORT_SYMBOL(of_node_get);
  33
  34 /**
  35  * of_node_put() - Decrement refcount of a node
  36  * @node:       Node to dec refcount, NULL is supported to simplify writing of
  37  *              callers
  38  */
  39 void of_node_put(struct device_node *node)
  40 {
  41         if (node)
  42                 kobject_put(&node->kobj);
  43 }
  44 EXPORT_SYMBOL(of_node_put);
  45
  46 void __of_detach_node_sysfs(struct device_node *np)
  47 {
  48         struct property *pp;
  49
  50         if (!IS_ENABLED(CONFIG_SYSFS))
  51                 return;
  52
  53         BUG_ON(!of_node_is_initialized(np));
  54         if (!of_kset)
  55                 return;
  56
  57         /* only remove properties if on sysfs */
  58         if (of_node_is_attached(np)) {
  59                 for_each_property_of_node(np, pp)
  60                         __of_sysfs_remove_bin_file(np, pp);
  61                 kobject_del(&np->kobj);
  62         }
  63
  64         /* finally remove the kobj_init ref */
  65         of_node_put(np);
  66 }
  67
  68 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
  69
  70 int of_reconfig_notifier_register(struct notifier_block *nb)
  71 {
  72         return blocking_notifier_chain_register(&of_reconfig_chain, nb);
  73 }
  74 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
  75
  76 int of_reconfig_notifier_unregister(struct notifier_block *nb)
  77 {
  78         return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
  79 }
  80 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
  81
  82 #ifdef DEBUG
  83 const char *action_names[] = {
  84         [OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
  85         [OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
  86         [OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
  87         [OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
  88         [OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
  89 };
  90 #endif
  91
  92 int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
  93 {
  94         int rc;
  95 #ifdef DEBUG
  96         struct of_reconfig_data *pr = p;
  97
  98         switch (action) {
  99         case OF_RECONFIG_ATTACH_NODE:
 100         case OF_RECONFIG_DETACH_NODE:
 101                 pr_debug("notify %-15s %pOF\n", action_names[action],
 102                         pr->dn);
 103                 break;
 104         case OF_RECONFIG_ADD_PROPERTY:
 105         case OF_RECONFIG_REMOVE_PROPERTY:
 106         case OF_RECONFIG_UPDATE_PROPERTY:
 107                 pr_debug("notify %-15s %pOF:%s\n", action_names[action],
 108                         pr->dn, pr->prop->name);
 109                 break;
 110
 111         }
 112 #endif
 113         rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
 114         return notifier_to_errno(rc);
 115 }
 116
 117 /*
 118  * of_reconfig_get_state_change()       - Returns new state of device
 119  * @action      - action of the of notifier
 120  * @arg         - argument of the of notifier
 121  *
 122  * Returns the new state of a device based on the notifier used.
 123  * Returns 0 on device going from enabled to disabled, 1 on device
 124  * going from disabled to enabled and -1 on no change.
 125  */
 126 int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
 127 {
 128         struct property *prop, *old_prop = NULL;
 129         int is_status, status_state, old_status_state, prev_state, new_state;
 130
 131         /* figure out if a device should be created or destroyed */
 132         switch (action) {
 133         case OF_RECONFIG_ATTACH_NODE:
 134         case OF_RECONFIG_DETACH_NODE:
 135                 prop = of_find_property(pr->dn, "status", NULL);
 136                 break;
 137         case OF_RECONFIG_ADD_PROPERTY:
 138         case OF_RECONFIG_REMOVE_PROPERTY:
 139                 prop = pr->prop;
 140                 break;
 141         case OF_RECONFIG_UPDATE_PROPERTY:
 142                 prop = pr->prop;
 143                 old_prop = pr->old_prop;
 144                 break;
 145         default:
 146                 return OF_RECONFIG_NO_CHANGE;
 147         }
 148
 149         is_status = 0;
 150         status_state = -1;
 151         old_status_state = -1;
 152         prev_state = -1;
 153         new_state = -1;
 154
 155         if (prop && !strcmp(prop->name, "status")) {
 156                 is_status = 1;
 157                 status_state = !strcmp(prop->value, "okay") ||
 158                                !strcmp(prop->value, "ok");
 159                 if (old_prop)
 160                         old_status_state = !strcmp(old_prop->value, "okay") ||
 161                                            !strcmp(old_prop->value, "ok");
 162         }
 163
 164         switch (action) {
 165         case OF_RECONFIG_ATTACH_NODE:
 166                 prev_state = 0;
 167                 /* -1 & 0 status either missing or okay */
 168                 new_state = status_state != 0;
 169                 break;
 170         case OF_RECONFIG_DETACH_NODE:
 171                 /* -1 & 0 status either missing or okay */
 172                 prev_state = status_state != 0;
 173                 new_state = 0;
 174                 break;
 175         case OF_RECONFIG_ADD_PROPERTY:
 176                 if (is_status) {
 177                         /* no status property -> enabled (legacy) */
 178                         prev_state = 1;
 179                         new_state = status_state;
 180                 }
 181                 break;
 182         case OF_RECONFIG_REMOVE_PROPERTY:
 183                 if (is_status) {
 184                         prev_state = status_state;
 185                         /* no status property -> enabled (legacy) */
 186                         new_state = 1;
 187                 }
 188                 break;
 189         case OF_RECONFIG_UPDATE_PROPERTY:
 190                 if (is_status) {
 191                         prev_state = old_status_state != 0;
 192                         new_state = status_state != 0;
 193                 }
 194                 break;
 195         }
 196
 197         if (prev_state == new_state)
 198                 return OF_RECONFIG_NO_CHANGE;
 199
 200         return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
 201 }
 202 EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
 203
 204 int of_property_notify(int action, struct device_node *np,
 205                        struct property *prop, struct property *oldprop)
 206 {
 207         struct of_reconfig_data pr;
 208
 209         /* only call notifiers if the node is attached */
 210         if (!of_node_is_attached(np))
 211                 return 0;
 212
 213         pr.dn = np;
 214         pr.prop = prop;
 215         pr.old_prop = oldprop;
 216         return of_reconfig_notify(action, &pr);
 217 }
 218
 219 static void __of_attach_node(struct device_node *np)
 220 {
 221         const __be32 *phandle;
 222         int sz;
 223
 224         np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
 225         np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
 226
 227         phandle = __of_get_property(np, "phandle", &sz);
 228         if (!phandle)
 229                 phandle = __of_get_property(np, "linux,phandle", &sz);
 230         if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
 231                 phandle = __of_get_property(np, "ibm,phandle", &sz);
 232         np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
 233
 234         np->child = NULL;
 235         np->sibling = np->parent->child;
 236         np->parent->child = np;
 237         of_node_clear_flag(np, OF_DETACHED);
 238 }
 239
 240 /**
 241  * of_attach_node() - Plug a device node into the tree and global list.
 242  */
 243 int of_attach_node(struct device_node *np)
 244 {
 245         struct of_reconfig_data rd;
 246         unsigned long flags;
 247
 248         memset(&rd, 0, sizeof(rd));
 249         rd.dn = np;
 250
 251         mutex_lock(&of_mutex);
 252         raw_spin_lock_irqsave(&devtree_lock, flags);
 253         __of_attach_node(np);
 254         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 255
 256         __of_attach_node_sysfs(np);
 257         mutex_unlock(&of_mutex);
 258
 259         of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
 260
 261         return 0;
 262 }
 263
 264 void __of_detach_node(struct device_node *np)
 265 {
 266         struct device_node *parent;
 267
 268         if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
 269                 return;
 270
 271         parent = np->parent;
 272         if (WARN_ON(!parent))
 273                 return;
 274
 275         if (parent->child == np)
 276                 parent->child = np->sibling;
 277         else {
 278                 struct device_node *prevsib;
 279                 for (prevsib = np->parent->child;
 280                      prevsib->sibling != np;
 281                      prevsib = prevsib->sibling)
 282                         ;
 283                 prevsib->sibling = np->sibling;
 284         }
 285
 286         of_node_set_flag(np, OF_DETACHED);
 287 }
 288
 289 /**
 290  * of_detach_node() - "Unplug" a node from the device tree.
 291  *
 292  * The caller must hold a reference to the node.  The memory associated with
 293  * the node is not freed until its refcount goes to zero.
 294  */
 295 int of_detach_node(struct device_node *np)
 296 {
 297         struct of_reconfig_data rd;
 298         unsigned long flags;
 299         int rc = 0;
 300
 301         memset(&rd, 0, sizeof(rd));
 302         rd.dn = np;
 303
 304         mutex_lock(&of_mutex);
 305         raw_spin_lock_irqsave(&devtree_lock, flags);
 306         __of_detach_node(np);
 307         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 308
 309         __of_detach_node_sysfs(np);
 310         mutex_unlock(&of_mutex);
 311
 312         of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
 313
 314         return rc;
 315 }
 316 EXPORT_SYMBOL_GPL(of_detach_node);
 317
 318 /**
 319  * of_node_release() - release a dynamically allocated node
 320  * @kref: kref element of the node to be released
 321  *
 322  * In of_node_put() this function is passed to kref_put() as the destructor.
 323  */
 324 void of_node_release(struct kobject *kobj)
 325 {
 326         struct device_node *node = kobj_to_device_node(kobj);
 327         struct property *prop = node->properties;
 328
 329         /* We should never be releasing nodes that haven't been detached. */
 330         if (!of_node_check_flag(node, OF_DETACHED)) {
 331                 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
 332                 dump_stack();
 333                 return;
 334         }
 335         if (!of_node_check_flag(node, OF_DYNAMIC))
 336                 return;
 337
 338         while (prop) {
 339                 struct property *next = prop->next;
 340                 kfree(prop->name);
 341                 kfree(prop->value);
 342                 kfree(prop);
 343                 prop = next;
 344
 345                 if (!prop) {
 346                         prop = node->deadprops;
 347                         node->deadprops = NULL;
 348                 }
 349         }
 350         kfree(node->full_name);
 351         kfree(node->data);
 352         kfree(node);
 353 }
 354
 355 /**
 356  * __of_prop_dup - Copy a property dynamically.
 357  * @prop:       Property to copy
 358  * @allocflags: Allocation flags (typically pass GFP_KERNEL)
 359  *
 360  * Copy a property by dynamically allocating the memory of both the
 361  * property structure and the property name & contents. The property's
 362  * flags have the OF_DYNAMIC bit set so that we can differentiate between
 363  * dynamically allocated properties and not.
 364  * Returns the newly allocated property or NULL on out of memory error.
 365  */
 366 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
 367 {
 368         struct property *new;
 369
 370         new = kzalloc(sizeof(*new), allocflags);
 371         if (!new)
 372                 return NULL;
 373
 374         /*
 375          * NOTE: There is no check for zero length value.
 376          * In case of a boolean property, this will allocate a value
 377          * of zero bytes. We do this to work around the use
 378          * of of_get_property() calls on boolean values.
 379          */
 380         new->name = kstrdup(prop->name, allocflags);
 381         new->value = kmemdup(prop->value, prop->length, allocflags);
 382         new->length = prop->length;
 383         if (!new->name || !new->value)
 384                 goto err_free;
 385
 386         /* mark the property as dynamic */
 387         of_property_set_flag(new, OF_DYNAMIC);
 388
 389         return new;
 390
 391  err_free:
 392         kfree(new->name);
 393         kfree(new->value);
 394         kfree(new);
 395         return NULL;
 396 }
 397
 398 /**
 399  * __of_node_dup() - Duplicate or create an empty device node dynamically.
 400  * @fmt: Format string (plus vargs) for new full name of the device node
 401  *
 402  * Create an device tree node, either by duplicating an empty node or by allocating
 403  * an empty one suitable for further modification.  The node data are
 404  * dynamically allocated and all the node flags have the OF_DYNAMIC &
 405  * OF_DETACHED bits set. Returns the newly allocated node or NULL on out of
 406  * memory error.
 407  */
 408 struct device_node *__of_node_dup(const struct device_node *np, const char *fmt, ...)
 409 {
 410         va_list vargs;
 411         struct device_node *node;
 412
 413         node = kzalloc(sizeof(*node), GFP_KERNEL);
 414         if (!node)
 415                 return NULL;
 416         va_start(vargs, fmt);
 417         node->full_name = kvasprintf(GFP_KERNEL, fmt, vargs);
 418         va_end(vargs);
 419         if (!node->full_name) {
 420                 kfree(node);
 421                 return NULL;
 422         }
 423
 424         of_node_set_flag(node, OF_DYNAMIC);
 425         of_node_set_flag(node, OF_DETACHED);
 426         of_node_init(node);
 427
 428         /* Iterate over and duplicate all properties */
 429         if (np) {
 430                 struct property *pp, *new_pp;
 431                 for_each_property_of_node(np, pp) {
 432                         new_pp = __of_prop_dup(pp, GFP_KERNEL);
 433                         if (!new_pp)
 434                                 goto err_prop;
 435                         if (__of_add_property(node, new_pp)) {
 436                                 kfree(new_pp->name);
 437                                 kfree(new_pp->value);
 438                                 kfree(new_pp);
 439                                 goto err_prop;
 440                         }
 441                 }
 442         }
 443         return node;
 444
 445  err_prop:
 446         of_node_put(node); /* Frees the node and properties */
 447         return NULL;
 448 }
 449
 450 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 451 {
 452         of_node_put(ce->np);
 453         list_del(&ce->node);
 454         kfree(ce);
 455 }
 456
 457 #ifdef DEBUG
 458 static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 459 {
 460         switch (ce->action) {
 461         case OF_RECONFIG_ADD_PROPERTY:
 462         case OF_RECONFIG_REMOVE_PROPERTY:
 463         case OF_RECONFIG_UPDATE_PROPERTY:
 464                 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
 465                         ce->np, ce->prop->name);
 466                 break;
 467         case OF_RECONFIG_ATTACH_NODE:
 468         case OF_RECONFIG_DETACH_NODE:
 469                 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
 470                         ce->np);
 471                 break;
 472         }
 473 }
 474 #else
 475 static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 476 {
 477         /* empty */
 478 }
 479 #endif
 480
 481 static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
 482                                           struct of_changeset_entry *rce)
 483 {
 484         memcpy(rce, ce, sizeof(*rce));
 485
 486         switch (ce->action) {
 487         case OF_RECONFIG_ATTACH_NODE:
 488                 rce->action = OF_RECONFIG_DETACH_NODE;
 489                 break;
 490         case OF_RECONFIG_DETACH_NODE:
 491                 rce->action = OF_RECONFIG_ATTACH_NODE;
 492                 break;
 493         case OF_RECONFIG_ADD_PROPERTY:
 494                 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 495                 break;
 496         case OF_RECONFIG_REMOVE_PROPERTY:
 497                 rce->action = OF_RECONFIG_ADD_PROPERTY;
 498                 break;
 499         case OF_RECONFIG_UPDATE_PROPERTY:
 500                 rce->old_prop = ce->prop;
 501                 rce->prop = ce->old_prop;
 502                 /* update was used but original property did not exist */
 503                 if (!rce->prop) {
 504                         rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 505                         rce->prop = ce->prop;
 506                 }
 507                 break;
 508         }
 509 }
 510
 511 static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
 512 {
 513         struct of_reconfig_data rd;
 514         struct of_changeset_entry ce_inverted;
 515         int ret;
 516
 517         if (revert) {
 518                 __of_changeset_entry_invert(ce, &ce_inverted);
 519                 ce = &ce_inverted;
 520         }
 521
 522         switch (ce->action) {
 523         case OF_RECONFIG_ATTACH_NODE:
 524         case OF_RECONFIG_DETACH_NODE:
 525                 memset(&rd, 0, sizeof(rd));
 526                 rd.dn = ce->np;
 527                 ret = of_reconfig_notify(ce->action, &rd);
 528                 break;
 529         case OF_RECONFIG_ADD_PROPERTY:
 530         case OF_RECONFIG_REMOVE_PROPERTY:
 531         case OF_RECONFIG_UPDATE_PROPERTY:
 532                 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
 533                 break;
 534         default:
 535                 pr_err("invalid devicetree changeset action: %i\n",
 536                         (int)ce->action);
 537                 return;
 538         }
 539
 540         if (ret)
 541                 pr_err("changeset notifier error @%pOF\n", ce->np);
 542 }
 543
 544 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 545 {
 546         struct property *old_prop, **propp;
 547         unsigned long flags;
 548         int ret = 0;
 549
 550         __of_changeset_entry_dump(ce);
 551
 552         raw_spin_lock_irqsave(&devtree_lock, flags);
 553         switch (ce->action) {
 554         case OF_RECONFIG_ATTACH_NODE:
 555                 __of_attach_node(ce->np);
 556                 break;
 557         case OF_RECONFIG_DETACH_NODE:
 558                 __of_detach_node(ce->np);
 559                 break;
 560         case OF_RECONFIG_ADD_PROPERTY:
 561                 /* If the property is in deadprops then it must be removed */
 562                 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
 563                         if (*propp == ce->prop) {
 564                                 *propp = ce->prop->next;
 565                                 ce->prop->next = NULL;
 566                                 break;
 567                         }
 568                 }
 569
 570                 ret = __of_add_property(ce->np, ce->prop);
 571                 if (ret) {
 572                         pr_err("changeset: add_property failed @%pOF/%s\n",
 573                                 ce->np,
 574                                 ce->prop->name);
 575                         break;
 576                 }
 577                 break;
 578         case OF_RECONFIG_REMOVE_PROPERTY:
 579                 ret = __of_remove_property(ce->np, ce->prop);
 580                 if (ret) {
 581                         pr_err("changeset: remove_property failed @%pOF/%s\n",
 582                                 ce->np,
 583                                 ce->prop->name);
 584                         break;
 585                 }
 586                 break;
 587
 588         case OF_RECONFIG_UPDATE_PROPERTY:
 589                 /* If the property is in deadprops then it must be removed */
 590                 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
 591                         if (*propp == ce->prop) {
 592                                 *propp = ce->prop->next;
 593                                 ce->prop->next = NULL;
 594                                 break;
 595                         }
 596                 }
 597
 598                 ret = __of_update_property(ce->np, ce->prop, &old_prop);
 599                 if (ret) {
 600                         pr_err("changeset: update_property failed @%pOF/%s\n",
 601                                 ce->np,
 602                                 ce->prop->name);
 603                         break;
 604                 }
 605                 break;
 606         default:
 607                 ret = -EINVAL;
 608         }
 609         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 610
 611         if (ret)
 612                 return ret;
 613
 614         switch (ce->action) {
 615         case OF_RECONFIG_ATTACH_NODE:
 616                 __of_attach_node_sysfs(ce->np);
 617                 break;
 618         case OF_RECONFIG_DETACH_NODE:
 619                 __of_detach_node_sysfs(ce->np);
 620                 break;
 621         case OF_RECONFIG_ADD_PROPERTY:
 622                 /* ignore duplicate names */
 623                 __of_add_property_sysfs(ce->np, ce->prop);
 624                 break;
 625         case OF_RECONFIG_REMOVE_PROPERTY:
 626                 __of_remove_property_sysfs(ce->np, ce->prop);
 627                 break;
 628         case OF_RECONFIG_UPDATE_PROPERTY:
 629                 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
 630                 break;
 631         }
 632
 633         return 0;
 634 }
 635
 636 static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
 637 {
 638         struct of_changeset_entry ce_inverted;
 639
 640         __of_changeset_entry_invert(ce, &ce_inverted);
 641         return __of_changeset_entry_apply(&ce_inverted);
 642 }
 643
 644 /**
 645  * of_changeset_init - Initialize a changeset for use
 646  *
 647  * @ocs:        changeset pointer
 648  *
 649  * Initialize a changeset structure
 650  */
 651 void of_changeset_init(struct of_changeset *ocs)
 652 {
 653         memset(ocs, 0, sizeof(*ocs));
 654         INIT_LIST_HEAD(&ocs->entries);
 655 }
 656 EXPORT_SYMBOL_GPL(of_changeset_init);
 657
 658 /**
 659  * of_changeset_destroy - Destroy a changeset
 660  *
 661  * @ocs:        changeset pointer
 662  *
 663  * Destroys a changeset. Note that if a changeset is applied,
 664  * its changes to the tree cannot be reverted.
 665  */
 666 void of_changeset_destroy(struct of_changeset *ocs)
 667 {
 668         struct of_changeset_entry *ce, *cen;
 669
 670         list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
 671                 __of_changeset_entry_destroy(ce);
 672 }
 673 EXPORT_SYMBOL_GPL(of_changeset_destroy);
 674
 675 int __of_changeset_apply(struct of_changeset *ocs)
 676 {
 677         struct of_changeset_entry *ce;
 678         int ret;
 679
 680         /* perform the rest of the work */
 681         pr_debug("changeset: applying...\n");
 682         list_for_each_entry(ce, &ocs->entries, node) {
 683                 ret = __of_changeset_entry_apply(ce);
 684                 if (ret) {
 685                         pr_err("Error applying changeset (%d)\n", ret);
 686                         list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
 687                                 __of_changeset_entry_revert(ce);
 688                         return ret;
 689                 }
 690         }
 691         pr_debug("changeset: applied, emitting notifiers.\n");
 692
 693         /* drop the global lock while emitting notifiers */
 694         mutex_unlock(&of_mutex);
 695         list_for_each_entry(ce, &ocs->entries, node)
 696                 __of_changeset_entry_notify(ce, 0);
 697         mutex_lock(&of_mutex);
 698         pr_debug("changeset: notifiers sent.\n");
 699
 700         return 0;
 701 }
 702
 703 /**
 704  * of_changeset_apply - Applies a changeset
 705  *
 706  * @ocs:        changeset pointer
 707  *
 708  * Applies a changeset to the live tree.
 709  * Any side-effects of live tree state changes are applied here on
 710  * success, like creation/destruction of devices and side-effects
 711  * like creation of sysfs properties and directories.
 712  * Returns 0 on success, a negative error value in case of an error.
 713  * On error the partially applied effects are reverted.
 714  */
 715 int of_changeset_apply(struct of_changeset *ocs)
 716 {
 717         int ret;
 718
 719         mutex_lock(&of_mutex);
 720         ret = __of_changeset_apply(ocs);
 721         mutex_unlock(&of_mutex);
 722
 723         return ret;
 724 }
 725 EXPORT_SYMBOL_GPL(of_changeset_apply);
 726
 727 int __of_changeset_revert(struct of_changeset *ocs)
 728 {
 729         struct of_changeset_entry *ce;
 730         int ret;
 731
 732         pr_debug("changeset: reverting...\n");
 733         list_for_each_entry_reverse(ce, &ocs->entries, node) {
 734                 ret = __of_changeset_entry_revert(ce);
 735                 if (ret) {
 736                         pr_err("Error reverting changeset (%d)\n", ret);
 737                         list_for_each_entry_continue(ce, &ocs->entries, node)
 738                                 __of_changeset_entry_apply(ce);
 739                         return ret;
 740                 }
 741         }
 742         pr_debug("changeset: reverted, emitting notifiers.\n");
 743
 744         /* drop the global lock while emitting notifiers */
 745         mutex_unlock(&of_mutex);
 746         list_for_each_entry_reverse(ce, &ocs->entries, node)
 747                 __of_changeset_entry_notify(ce, 1);
 748         mutex_lock(&of_mutex);
 749         pr_debug("changeset: notifiers sent.\n");
 750
 751         return 0;
 752 }
 753
 754 /**
 755  * of_changeset_revert - Reverts an applied changeset
 756  *
 757  * @ocs:        changeset pointer
 758  *
 759  * Reverts a changeset returning the state of the tree to what it
 760  * was before the application.
 761  * Any side-effects like creation/destruction of devices and
 762  * removal of sysfs properties and directories are applied.
 763  * Returns 0 on success, a negative error value in case of an error.
 764  */
 765 int of_changeset_revert(struct of_changeset *ocs)
 766 {
 767         int ret;
 768
 769         mutex_lock(&of_mutex);
 770         ret = __of_changeset_revert(ocs);
 771         mutex_unlock(&of_mutex);
 772
 773         return ret;
 774 }
 775 EXPORT_SYMBOL_GPL(of_changeset_revert);
 776
 777 /**
 778  * of_changeset_action - Perform a changeset action
 779  *
 780  * @ocs:        changeset pointer
 781  * @action:     action to perform
 782  * @np:         Pointer to device node
 783  * @prop:       Pointer to property
 784  *
 785  * On action being one of:
 786  * + OF_RECONFIG_ATTACH_NODE
 787  * + OF_RECONFIG_DETACH_NODE,
 788  * + OF_RECONFIG_ADD_PROPERTY
 789  * + OF_RECONFIG_REMOVE_PROPERTY,
 790  * + OF_RECONFIG_UPDATE_PROPERTY
 791  * Returns 0 on success, a negative error value in case of an error.
 792  */
 793 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 794                 struct device_node *np, struct property *prop)
 795 {
 796         struct of_changeset_entry *ce;
 797
 798         ce = kzalloc(sizeof(*ce), GFP_KERNEL);
 799         if (!ce)
 800                 return -ENOMEM;
 801
 802         /* get a reference to the node */
 803         ce->action = action;
 804         ce->np = of_node_get(np);
 805         ce->prop = prop;
 806
 807         if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
 808                 ce->old_prop = of_find_property(np, prop->name, NULL);
 809
 810         /* add it to the list */
 811         list_add_tail(&ce->node, &ocs->entries);
 812         return 0;
 813 }
 814 EXPORT_SYMBOL_GPL(of_changeset_action);