drivers/of/dynamic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Support for dynamic device trees.
   4  *
   5  * On some platforms, the device tree can be manipulated at runtime.
   6  * The routines in this section support adding, removing and changing
   7  * device tree nodes.
   8  */
   9
  10 #define pr_fmt(fmt)     "OF: " fmt
  11
  12 #include <linux/of.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/slab.h>
  15 #include <linux/string.h>
  16 #include <linux/proc_fs.h>
  17
  18 #include "of_private.h"
  19
  20 static struct device_node *kobj_to_device_node(struct kobject *kobj)
  21 {
  22         return container_of(kobj, struct device_node, kobj);
  23 }
  24
  25 /**
  26  * of_node_get() - Increment refcount of a node
  27  * @node:       Node to inc refcount, NULL is supported to simplify writing of
  28  *              callers
  29  *
  30  * Returns node.
  31  */
  32 struct device_node *of_node_get(struct device_node *node)
  33 {
  34         if (node)
  35                 kobject_get(&node->kobj);
  36         return node;
  37 }
  38 EXPORT_SYMBOL(of_node_get);
  39
  40 /**
  41  * of_node_put() - Decrement refcount of a node
  42  * @node:       Node to dec refcount, NULL is supported to simplify writing of
  43  *              callers
  44  */
  45 void of_node_put(struct device_node *node)
  46 {
  47         if (node)
  48                 kobject_put(&node->kobj);
  49 }
  50 EXPORT_SYMBOL(of_node_put);
  51
  52 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
  53
  54 int of_reconfig_notifier_register(struct notifier_block *nb)
  55 {
  56         return blocking_notifier_chain_register(&of_reconfig_chain, nb);
  57 }
  58 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
  59
  60 int of_reconfig_notifier_unregister(struct notifier_block *nb)
  61 {
  62         return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
  63 }
  64 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
  65
  66 #ifdef DEBUG
  67 const char *action_names[] = {
  68         [OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
  69         [OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
  70         [OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
  71         [OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
  72         [OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
  73 };
  74 #endif
  75
  76 int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
  77 {
  78         int rc;
  79 #ifdef DEBUG
  80         struct of_reconfig_data *pr = p;
  81
  82         switch (action) {
  83         case OF_RECONFIG_ATTACH_NODE:
  84         case OF_RECONFIG_DETACH_NODE:
  85                 pr_debug("notify %-15s %pOF\n", action_names[action],
  86                         pr->dn);
  87                 break;
  88         case OF_RECONFIG_ADD_PROPERTY:
  89         case OF_RECONFIG_REMOVE_PROPERTY:
  90         case OF_RECONFIG_UPDATE_PROPERTY:
  91                 pr_debug("notify %-15s %pOF:%s\n", action_names[action],
  92                         pr->dn, pr->prop->name);
  93                 break;
  94
  95         }
  96 #endif
  97         rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
  98         return notifier_to_errno(rc);
  99 }
 100
 101 /*
 102  * of_reconfig_get_state_change()       - Returns new state of device
 103  * @action      - action of the of notifier
 104  * @arg         - argument of the of notifier
 105  *
 106  * Returns the new state of a device based on the notifier used.
 107  * Returns 0 on device going from enabled to disabled, 1 on device
 108  * going from disabled to enabled and -1 on no change.
 109  */
 110 int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
 111 {
 112         struct property *prop, *old_prop = NULL;
 113         int is_status, status_state, old_status_state, prev_state, new_state;
 114
 115         /* figure out if a device should be created or destroyed */
 116         switch (action) {
 117         case OF_RECONFIG_ATTACH_NODE:
 118         case OF_RECONFIG_DETACH_NODE:
 119                 prop = of_find_property(pr->dn, "status", NULL);
 120                 break;
 121         case OF_RECONFIG_ADD_PROPERTY:
 122         case OF_RECONFIG_REMOVE_PROPERTY:
 123                 prop = pr->prop;
 124                 break;
 125         case OF_RECONFIG_UPDATE_PROPERTY:
 126                 prop = pr->prop;
 127                 old_prop = pr->old_prop;
 128                 break;
 129         default:
 130                 return OF_RECONFIG_NO_CHANGE;
 131         }
 132
 133         is_status = 0;
 134         status_state = -1;
 135         old_status_state = -1;
 136         prev_state = -1;
 137         new_state = -1;
 138
 139         if (prop && !strcmp(prop->name, "status")) {
 140                 is_status = 1;
 141                 status_state = !strcmp(prop->value, "okay") ||
 142                                !strcmp(prop->value, "ok");
 143                 if (old_prop)
 144                         old_status_state = !strcmp(old_prop->value, "okay") ||
 145                                            !strcmp(old_prop->value, "ok");
 146         }
 147
 148         switch (action) {
 149         case OF_RECONFIG_ATTACH_NODE:
 150                 prev_state = 0;
 151                 /* -1 & 0 status either missing or okay */
 152                 new_state = status_state != 0;
 153                 break;
 154         case OF_RECONFIG_DETACH_NODE:
 155                 /* -1 & 0 status either missing or okay */
 156                 prev_state = status_state != 0;
 157                 new_state = 0;
 158                 break;
 159         case OF_RECONFIG_ADD_PROPERTY:
 160                 if (is_status) {
 161                         /* no status property -> enabled (legacy) */
 162                         prev_state = 1;
 163                         new_state = status_state;
 164                 }
 165                 break;
 166         case OF_RECONFIG_REMOVE_PROPERTY:
 167                 if (is_status) {
 168                         prev_state = status_state;
 169                         /* no status property -> enabled (legacy) */
 170                         new_state = 1;
 171                 }
 172                 break;
 173         case OF_RECONFIG_UPDATE_PROPERTY:
 174                 if (is_status) {
 175                         prev_state = old_status_state != 0;
 176                         new_state = status_state != 0;
 177                 }
 178                 break;
 179         }
 180
 181         if (prev_state == new_state)
 182                 return OF_RECONFIG_NO_CHANGE;
 183
 184         return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
 185 }
 186 EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
 187
 188 int of_property_notify(int action, struct device_node *np,
 189                        struct property *prop, struct property *oldprop)
 190 {
 191         struct of_reconfig_data pr;
 192
 193         /* only call notifiers if the node is attached */
 194         if (!of_node_is_attached(np))
 195                 return 0;
 196
 197         pr.dn = np;
 198         pr.prop = prop;
 199         pr.old_prop = oldprop;
 200         return of_reconfig_notify(action, &pr);
 201 }
 202
 203 static void __of_attach_node(struct device_node *np)
 204 {
 205         const __be32 *phandle;
 206         int sz;
 207
 208         np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
 209         np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
 210
 211         phandle = __of_get_property(np, "phandle", &sz);
 212         if (!phandle)
 213                 phandle = __of_get_property(np, "linux,phandle", &sz);
 214         if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
 215                 phandle = __of_get_property(np, "ibm,phandle", &sz);
 216         np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
 217
 218         np->child = NULL;
 219         np->sibling = np->parent->child;
 220         np->parent->child = np;
 221         of_node_clear_flag(np, OF_DETACHED);
 222 }
 223
 224 /**
 225  * of_attach_node() - Plug a device node into the tree and global list.
 226  */
 227 int of_attach_node(struct device_node *np)
 228 {
 229         struct of_reconfig_data rd;
 230         unsigned long flags;
 231
 232         memset(&rd, 0, sizeof(rd));
 233         rd.dn = np;
 234
 235         mutex_lock(&of_mutex);
 236         raw_spin_lock_irqsave(&devtree_lock, flags);
 237         __of_attach_node(np);
 238         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 239
 240         __of_attach_node_sysfs(np);
 241         mutex_unlock(&of_mutex);
 242
 243         of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
 244
 245         return 0;
 246 }
 247
 248 void __of_detach_node(struct device_node *np)
 249 {
 250         struct device_node *parent;
 251
 252         if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
 253                 return;
 254
 255         parent = np->parent;
 256         if (WARN_ON(!parent))
 257                 return;
 258
 259         if (parent->child == np)
 260                 parent->child = np->sibling;
 261         else {
 262                 struct device_node *prevsib;
 263                 for (prevsib = np->parent->child;
 264                      prevsib->sibling != np;
 265                      prevsib = prevsib->sibling)
 266                         ;
 267                 prevsib->sibling = np->sibling;
 268         }
 269
 270         of_node_set_flag(np, OF_DETACHED);
 271 }
 272
 273 /**
 274  * of_detach_node() - "Unplug" a node from the device tree.
 275  *
 276  * The caller must hold a reference to the node.  The memory associated with
 277  * the node is not freed until its refcount goes to zero.
 278  */
 279 int of_detach_node(struct device_node *np)
 280 {
 281         struct of_reconfig_data rd;
 282         unsigned long flags;
 283         int rc = 0;
 284
 285         memset(&rd, 0, sizeof(rd));
 286         rd.dn = np;
 287
 288         mutex_lock(&of_mutex);
 289         raw_spin_lock_irqsave(&devtree_lock, flags);
 290         __of_detach_node(np);
 291         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 292
 293         __of_detach_node_sysfs(np);
 294         mutex_unlock(&of_mutex);
 295
 296         of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
 297
 298         return rc;
 299 }
 300 EXPORT_SYMBOL_GPL(of_detach_node);
 301
 302 static void property_list_free(struct property *prop_list)
 303 {
 304         struct property *prop, *next;
 305
 306         for (prop = prop_list; prop != NULL; prop = next) {
 307                 next = prop->next;
 308                 kfree(prop->name);
 309                 kfree(prop->value);
 310                 kfree(prop);
 311         }
 312 }
 313
 314 /**
 315  * of_node_release() - release a dynamically allocated node
 316  * @kref: kref element of the node to be released
 317  *
 318  * In of_node_put() this function is passed to kref_put() as the destructor.
 319  */
 320 void of_node_release(struct kobject *kobj)
 321 {
 322         struct device_node *node = kobj_to_device_node(kobj);
 323
 324         /* We should never be releasing nodes that haven't been detached. */
 325         if (!of_node_check_flag(node, OF_DETACHED)) {
 326                 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
 327                 dump_stack();
 328                 return;
 329         }
 330         if (!of_node_check_flag(node, OF_DYNAMIC))
 331                 return;
 332
 333         property_list_free(node->properties);
 334         property_list_free(node->deadprops);
 335
 336         kfree(node->full_name);
 337         kfree(node->data);
 338         kfree(node);
 339 }
 340
 341 /**
 342  * __of_prop_dup - Copy a property dynamically.
 343  * @prop:       Property to copy
 344  * @allocflags: Allocation flags (typically pass GFP_KERNEL)
 345  *
 346  * Copy a property by dynamically allocating the memory of both the
 347  * property structure and the property name & contents. The property's
 348  * flags have the OF_DYNAMIC bit set so that we can differentiate between
 349  * dynamically allocated properties and not.
 350  * Returns the newly allocated property or NULL on out of memory error.
 351  */
 352 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
 353 {
 354         struct property *new;
 355
 356         new = kzalloc(sizeof(*new), allocflags);
 357         if (!new)
 358                 return NULL;
 359
 360         /*
 361          * NOTE: There is no check for zero length value.
 362          * In case of a boolean property, this will allocate a value
 363          * of zero bytes. We do this to work around the use
 364          * of of_get_property() calls on boolean values.
 365          */
 366         new->name = kstrdup(prop->name, allocflags);
 367         new->value = kmemdup(prop->value, prop->length, allocflags);
 368         new->length = prop->length;
 369         if (!new->name || !new->value)
 370                 goto err_free;
 371
 372         /* mark the property as dynamic */
 373         of_property_set_flag(new, OF_DYNAMIC);
 374
 375         return new;
 376
 377  err_free:
 378         kfree(new->name);
 379         kfree(new->value);
 380         kfree(new);
 381         return NULL;
 382 }
 383
 384 /**
 385  * __of_node_dup() - Duplicate or create an empty device node dynamically.
 386  * @fmt: Format string (plus vargs) for new full name of the device node
 387  *
 388  * Create an device tree node, either by duplicating an empty node or by allocating
 389  * an empty one suitable for further modification.  The node data are
 390  * dynamically allocated and all the node flags have the OF_DYNAMIC &
 391  * OF_DETACHED bits set. Returns the newly allocated node or NULL on out of
 392  * memory error.
 393  */
 394 struct device_node *__of_node_dup(const struct device_node *np, const char *fmt, ...)
 395 {
 396         va_list vargs;
 397         struct device_node *node;
 398
 399         node = kzalloc(sizeof(*node), GFP_KERNEL);
 400         if (!node)
 401                 return NULL;
 402         va_start(vargs, fmt);
 403         node->full_name = kvasprintf(GFP_KERNEL, fmt, vargs);
 404         va_end(vargs);
 405         if (!node->full_name) {
 406                 kfree(node);
 407                 return NULL;
 408         }
 409
 410         of_node_set_flag(node, OF_DYNAMIC);
 411         of_node_set_flag(node, OF_DETACHED);
 412         of_node_init(node);
 413
 414         /* Iterate over and duplicate all properties */
 415         if (np) {
 416                 struct property *pp, *new_pp;
 417                 for_each_property_of_node(np, pp) {
 418                         new_pp = __of_prop_dup(pp, GFP_KERNEL);
 419                         if (!new_pp)
 420                                 goto err_prop;
 421                         if (__of_add_property(node, new_pp)) {
 422                                 kfree(new_pp->name);
 423                                 kfree(new_pp->value);
 424                                 kfree(new_pp);
 425                                 goto err_prop;
 426                         }
 427                 }
 428         }
 429         return node;
 430
 431  err_prop:
 432         of_node_put(node); /* Frees the node and properties */
 433         return NULL;
 434 }
 435
 436 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 437 {
 438         of_node_put(ce->np);
 439         list_del(&ce->node);
 440         kfree(ce);
 441 }
 442
 443 #ifdef DEBUG
 444 static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 445 {
 446         switch (ce->action) {
 447         case OF_RECONFIG_ADD_PROPERTY:
 448         case OF_RECONFIG_REMOVE_PROPERTY:
 449         case OF_RECONFIG_UPDATE_PROPERTY:
 450                 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
 451                         ce->np, ce->prop->name);
 452                 break;
 453         case OF_RECONFIG_ATTACH_NODE:
 454         case OF_RECONFIG_DETACH_NODE:
 455                 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
 456                         ce->np);
 457                 break;
 458         }
 459 }
 460 #else
 461 static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 462 {
 463         /* empty */
 464 }
 465 #endif
 466
 467 static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
 468                                           struct of_changeset_entry *rce)
 469 {
 470         memcpy(rce, ce, sizeof(*rce));
 471
 472         switch (ce->action) {
 473         case OF_RECONFIG_ATTACH_NODE:
 474                 rce->action = OF_RECONFIG_DETACH_NODE;
 475                 break;
 476         case OF_RECONFIG_DETACH_NODE:
 477                 rce->action = OF_RECONFIG_ATTACH_NODE;
 478                 break;
 479         case OF_RECONFIG_ADD_PROPERTY:
 480                 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 481                 break;
 482         case OF_RECONFIG_REMOVE_PROPERTY:
 483                 rce->action = OF_RECONFIG_ADD_PROPERTY;
 484                 break;
 485         case OF_RECONFIG_UPDATE_PROPERTY:
 486                 rce->old_prop = ce->prop;
 487                 rce->prop = ce->old_prop;
 488                 /* update was used but original property did not exist */
 489                 if (!rce->prop) {
 490                         rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 491                         rce->prop = ce->prop;
 492                 }
 493                 break;
 494         }
 495 }
 496
 497 static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
 498                 bool revert)
 499 {
 500         struct of_reconfig_data rd;
 501         struct of_changeset_entry ce_inverted;
 502         int ret = 0;
 503
 504         if (revert) {
 505                 __of_changeset_entry_invert(ce, &ce_inverted);
 506                 ce = &ce_inverted;
 507         }
 508
 509         switch (ce->action) {
 510         case OF_RECONFIG_ATTACH_NODE:
 511         case OF_RECONFIG_DETACH_NODE:
 512                 memset(&rd, 0, sizeof(rd));
 513                 rd.dn = ce->np;
 514                 ret = of_reconfig_notify(ce->action, &rd);
 515                 break;
 516         case OF_RECONFIG_ADD_PROPERTY:
 517         case OF_RECONFIG_REMOVE_PROPERTY:
 518         case OF_RECONFIG_UPDATE_PROPERTY:
 519                 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
 520                 break;
 521         default:
 522                 pr_err("invalid devicetree changeset action: %i\n",
 523                         (int)ce->action);
 524                 ret = -EINVAL;
 525         }
 526
 527         if (ret)
 528                 pr_err("changeset notifier error @%pOF\n", ce->np);
 529         return ret;
 530 }
 531
 532 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 533 {
 534         struct property *old_prop, **propp;
 535         unsigned long flags;
 536         int ret = 0;
 537
 538         __of_changeset_entry_dump(ce);
 539
 540         raw_spin_lock_irqsave(&devtree_lock, flags);
 541         switch (ce->action) {
 542         case OF_RECONFIG_ATTACH_NODE:
 543                 __of_attach_node(ce->np);
 544                 break;
 545         case OF_RECONFIG_DETACH_NODE:
 546                 __of_detach_node(ce->np);
 547                 break;
 548         case OF_RECONFIG_ADD_PROPERTY:
 549                 /* If the property is in deadprops then it must be removed */
 550                 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
 551                         if (*propp == ce->prop) {
 552                                 *propp = ce->prop->next;
 553                                 ce->prop->next = NULL;
 554                                 break;
 555                         }
 556                 }
 557
 558                 ret = __of_add_property(ce->np, ce->prop);
 559                 if (ret) {
 560                         pr_err("changeset: add_property failed @%pOF/%s\n",
 561                                 ce->np,
 562                                 ce->prop->name);
 563                         break;
 564                 }
 565                 break;
 566         case OF_RECONFIG_REMOVE_PROPERTY:
 567                 ret = __of_remove_property(ce->np, ce->prop);
 568                 if (ret) {
 569                         pr_err("changeset: remove_property failed @%pOF/%s\n",
 570                                 ce->np,
 571                                 ce->prop->name);
 572                         break;
 573                 }
 574                 break;
 575
 576         case OF_RECONFIG_UPDATE_PROPERTY:
 577                 /* If the property is in deadprops then it must be removed */
 578                 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
 579                         if (*propp == ce->prop) {
 580                                 *propp = ce->prop->next;
 581                                 ce->prop->next = NULL;
 582                                 break;
 583                         }
 584                 }
 585
 586                 ret = __of_update_property(ce->np, ce->prop, &old_prop);
 587                 if (ret) {
 588                         pr_err("changeset: update_property failed @%pOF/%s\n",
 589                                 ce->np,
 590                                 ce->prop->name);
 591                         break;
 592                 }
 593                 break;
 594         default:
 595                 ret = -EINVAL;
 596         }
 597         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 598
 599         if (ret)
 600                 return ret;
 601
 602         switch (ce->action) {
 603         case OF_RECONFIG_ATTACH_NODE:
 604                 __of_attach_node_sysfs(ce->np);
 605                 break;
 606         case OF_RECONFIG_DETACH_NODE:
 607                 __of_detach_node_sysfs(ce->np);
 608                 break;
 609         case OF_RECONFIG_ADD_PROPERTY:
 610                 /* ignore duplicate names */
 611                 __of_add_property_sysfs(ce->np, ce->prop);
 612                 break;
 613         case OF_RECONFIG_REMOVE_PROPERTY:
 614                 __of_remove_property_sysfs(ce->np, ce->prop);
 615                 break;
 616         case OF_RECONFIG_UPDATE_PROPERTY:
 617                 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
 618                 break;
 619         }
 620
 621         return 0;
 622 }
 623
 624 static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
 625 {
 626         struct of_changeset_entry ce_inverted;
 627
 628         __of_changeset_entry_invert(ce, &ce_inverted);
 629         return __of_changeset_entry_apply(&ce_inverted);
 630 }
 631
 632 /**
 633  * of_changeset_init - Initialize a changeset for use
 634  *
 635  * @ocs:        changeset pointer
 636  *
 637  * Initialize a changeset structure
 638  */
 639 void of_changeset_init(struct of_changeset *ocs)
 640 {
 641         memset(ocs, 0, sizeof(*ocs));
 642         INIT_LIST_HEAD(&ocs->entries);
 643 }
 644 EXPORT_SYMBOL_GPL(of_changeset_init);
 645
 646 /**
 647  * of_changeset_destroy - Destroy a changeset
 648  *
 649  * @ocs:        changeset pointer
 650  *
 651  * Destroys a changeset. Note that if a changeset is applied,
 652  * its changes to the tree cannot be reverted.
 653  */
 654 void of_changeset_destroy(struct of_changeset *ocs)
 655 {
 656         struct of_changeset_entry *ce, *cen;
 657
 658         list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
 659                 __of_changeset_entry_destroy(ce);
 660 }
 661 EXPORT_SYMBOL_GPL(of_changeset_destroy);
 662
 663 /*
 664  * Apply the changeset entries in @ocs.
 665  * If apply fails, an attempt is made to revert the entries that were
 666  * successfully applied.
 667  *
 668  * If multiple revert errors occur then only the final revert error is reported.
 669  *
 670  * Returns 0 on success, a negative error value in case of an error.
 671  * If a revert error occurs, it is returned in *ret_revert.
 672  */
 673 int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
 674 {
 675         struct of_changeset_entry *ce;
 676         int ret, ret_tmp;
 677
 678         pr_debug("changeset: applying...\n");
 679         list_for_each_entry(ce, &ocs->entries, node) {
 680                 ret = __of_changeset_entry_apply(ce);
 681                 if (ret) {
 682                         pr_err("Error applying changeset (%d)\n", ret);
 683                         list_for_each_entry_continue_reverse(ce, &ocs->entries,
 684                                                              node) {
 685                                 ret_tmp = __of_changeset_entry_revert(ce);
 686                                 if (ret_tmp)
 687                                         *ret_revert = ret_tmp;
 688                         }
 689                         return ret;
 690                 }
 691         }
 692
 693         return 0;
 694 }
 695
 696 /*
 697  * Returns 0 on success, a negative error value in case of an error.
 698  *
 699  * If multiple changeset entry notification errors occur then only the
 700  * final notification error is reported.
 701  */
 702 int __of_changeset_apply_notify(struct of_changeset *ocs)
 703 {
 704         struct of_changeset_entry *ce;
 705         int ret = 0, ret_tmp;
 706
 707         pr_debug("changeset: emitting notifiers.\n");
 708
 709         /* drop the global lock while emitting notifiers */
 710         mutex_unlock(&of_mutex);
 711         list_for_each_entry(ce, &ocs->entries, node) {
 712                 ret_tmp = __of_changeset_entry_notify(ce, 0);
 713                 if (ret_tmp)
 714                         ret = ret_tmp;
 715         }
 716         mutex_lock(&of_mutex);
 717         pr_debug("changeset: notifiers sent.\n");
 718
 719         return ret;
 720 }
 721
 722 /*
 723  * Returns 0 on success, a negative error value in case of an error.
 724  *
 725  * If a changeset entry apply fails, an attempt is made to revert any
 726  * previous entries in the changeset.  If any of the reverts fails,
 727  * that failure is not reported.  Thus the state of the device tree
 728  * is unknown if an apply error occurs.
 729  */
 730 static int __of_changeset_apply(struct of_changeset *ocs)
 731 {
 732         int ret, ret_revert = 0;
 733
 734         ret = __of_changeset_apply_entries(ocs, &ret_revert);
 735         if (!ret)
 736                 ret = __of_changeset_apply_notify(ocs);
 737
 738         return ret;
 739 }
 740
 741 /**
 742  * of_changeset_apply - Applies a changeset
 743  *
 744  * @ocs:        changeset pointer
 745  *
 746  * Applies a changeset to the live tree.
 747  * Any side-effects of live tree state changes are applied here on
 748  * success, like creation/destruction of devices and side-effects
 749  * like creation of sysfs properties and directories.
 750  * Returns 0 on success, a negative error value in case of an error.
 751  * On error the partially applied effects are reverted.
 752  */
 753 int of_changeset_apply(struct of_changeset *ocs)
 754 {
 755         int ret;
 756
 757         mutex_lock(&of_mutex);
 758         ret = __of_changeset_apply(ocs);
 759         mutex_unlock(&of_mutex);
 760
 761         return ret;
 762 }
 763 EXPORT_SYMBOL_GPL(of_changeset_apply);
 764
 765 /*
 766  * Revert the changeset entries in @ocs.
 767  * If revert fails, an attempt is made to re-apply the entries that were
 768  * successfully removed.
 769  *
 770  * If multiple re-apply errors occur then only the final apply error is
 771  * reported.
 772  *
 773  * Returns 0 on success, a negative error value in case of an error.
 774  * If an apply error occurs, it is returned in *ret_apply.
 775  */
 776 int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
 777 {
 778         struct of_changeset_entry *ce;
 779         int ret, ret_tmp;
 780
 781         pr_debug("changeset: reverting...\n");
 782         list_for_each_entry_reverse(ce, &ocs->entries, node) {
 783                 ret = __of_changeset_entry_revert(ce);
 784                 if (ret) {
 785                         pr_err("Error reverting changeset (%d)\n", ret);
 786                         list_for_each_entry_continue(ce, &ocs->entries, node) {
 787                                 ret_tmp = __of_changeset_entry_apply(ce);
 788                                 if (ret_tmp)
 789                                         *ret_apply = ret_tmp;
 790                         }
 791                         return ret;
 792                 }
 793         }
 794
 795         return 0;
 796 }
 797
 798 /*
 799  * If multiple changeset entry notification errors occur then only the
 800  * final notification error is reported.
 801  */
 802 int __of_changeset_revert_notify(struct of_changeset *ocs)
 803 {
 804         struct of_changeset_entry *ce;
 805         int ret = 0, ret_tmp;
 806
 807         pr_debug("changeset: emitting notifiers.\n");
 808
 809         /* drop the global lock while emitting notifiers */
 810         mutex_unlock(&of_mutex);
 811         list_for_each_entry_reverse(ce, &ocs->entries, node) {
 812                 ret_tmp = __of_changeset_entry_notify(ce, 1);
 813                 if (ret_tmp)
 814                         ret = ret_tmp;
 815         }
 816         mutex_lock(&of_mutex);
 817         pr_debug("changeset: notifiers sent.\n");
 818
 819         return ret;
 820 }
 821
 822 static int __of_changeset_revert(struct of_changeset *ocs)
 823 {
 824         int ret, ret_reply;
 825
 826         ret_reply = 0;
 827         ret = __of_changeset_revert_entries(ocs, &ret_reply);
 828
 829         if (!ret)
 830                 ret = __of_changeset_revert_notify(ocs);
 831
 832         return ret;
 833 }
 834
 835 /**
 836  * of_changeset_revert - Reverts an applied changeset
 837  *
 838  * @ocs:        changeset pointer
 839  *
 840  * Reverts a changeset returning the state of the tree to what it
 841  * was before the application.
 842  * Any side-effects like creation/destruction of devices and
 843  * removal of sysfs properties and directories are applied.
 844  * Returns 0 on success, a negative error value in case of an error.
 845  */
 846 int of_changeset_revert(struct of_changeset *ocs)
 847 {
 848         int ret;
 849
 850         mutex_lock(&of_mutex);
 851         ret = __of_changeset_revert(ocs);
 852         mutex_unlock(&of_mutex);
 853
 854         return ret;
 855 }
 856 EXPORT_SYMBOL_GPL(of_changeset_revert);
 857
 858 /**
 859  * of_changeset_action - Add an action to the tail of the changeset list
 860  *
 861  * @ocs:        changeset pointer
 862  * @action:     action to perform
 863  * @np:         Pointer to device node
 864  * @prop:       Pointer to property
 865  *
 866  * On action being one of:
 867  * + OF_RECONFIG_ATTACH_NODE
 868  * + OF_RECONFIG_DETACH_NODE,
 869  * + OF_RECONFIG_ADD_PROPERTY
 870  * + OF_RECONFIG_REMOVE_PROPERTY,
 871  * + OF_RECONFIG_UPDATE_PROPERTY
 872  * Returns 0 on success, a negative error value in case of an error.
 873  */
 874 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 875                 struct device_node *np, struct property *prop)
 876 {
 877         struct of_changeset_entry *ce;
 878
 879         ce = kzalloc(sizeof(*ce), GFP_KERNEL);
 880         if (!ce)
 881                 return -ENOMEM;
 882
 883         /* get a reference to the node */
 884         ce->action = action;
 885         ce->np = of_node_get(np);
 886         ce->prop = prop;
 887
 888         if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
 889                 ce->old_prop = of_find_property(np, prop->name, NULL);
 890
 891         /* add it to the list */
 892         list_add_tail(&ce->node, &ocs->entries);
 893         return 0;
 894 }
 895 EXPORT_SYMBOL_GPL(of_changeset_action);