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