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  * Return: The node with refcount incremented.
  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  *
 108  * Return: 0 on device going from enabled to disabled, 1 on device
 109  * going from disabled to enabled and -1 on no change.
 110  */
 111 int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
 112 {
 113         struct property *prop, *old_prop = NULL;
 114         int is_status, status_state, old_status_state, prev_state, new_state;
 115
 116         /* figure out if a device should be created or destroyed */
 117         switch (action) {
 118         case OF_RECONFIG_ATTACH_NODE:
 119         case OF_RECONFIG_DETACH_NODE:
 120                 prop = of_find_property(pr->dn, "status", NULL);
 121                 break;
 122         case OF_RECONFIG_ADD_PROPERTY:
 123         case OF_RECONFIG_REMOVE_PROPERTY:
 124                 prop = pr->prop;
 125                 break;
 126         case OF_RECONFIG_UPDATE_PROPERTY:
 127                 prop = pr->prop;
 128                 old_prop = pr->old_prop;
 129                 break;
 130         default:
 131                 return OF_RECONFIG_NO_CHANGE;
 132         }
 133
 134         is_status = 0;
 135         status_state = -1;
 136         old_status_state = -1;
 137         prev_state = -1;
 138         new_state = -1;
 139
 140         if (prop && !strcmp(prop->name, "status")) {
 141                 is_status = 1;
 142                 status_state = !strcmp(prop->value, "okay") ||
 143                                !strcmp(prop->value, "ok");
 144                 if (old_prop)
 145                         old_status_state = !strcmp(old_prop->value, "okay") ||
 146                                            !strcmp(old_prop->value, "ok");
 147         }
 148
 149         switch (action) {
 150         case OF_RECONFIG_ATTACH_NODE:
 151                 prev_state = 0;
 152                 /* -1 & 0 status either missing or okay */
 153                 new_state = status_state != 0;
 154                 break;
 155         case OF_RECONFIG_DETACH_NODE:
 156                 /* -1 & 0 status either missing or okay */
 157                 prev_state = status_state != 0;
 158                 new_state = 0;
 159                 break;
 160         case OF_RECONFIG_ADD_PROPERTY:
 161                 if (is_status) {
 162                         /* no status property -> enabled (legacy) */
 163                         prev_state = 1;
 164                         new_state = status_state;
 165                 }
 166                 break;
 167         case OF_RECONFIG_REMOVE_PROPERTY:
 168                 if (is_status) {
 169                         prev_state = status_state;
 170                         /* no status property -> enabled (legacy) */
 171                         new_state = 1;
 172                 }
 173                 break;
 174         case OF_RECONFIG_UPDATE_PROPERTY:
 175                 if (is_status) {
 176                         prev_state = old_status_state != 0;
 177                         new_state = status_state != 0;
 178                 }
 179                 break;
 180         }
 181
 182         if (prev_state == new_state)
 183                 return OF_RECONFIG_NO_CHANGE;
 184
 185         return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
 186 }
 187 EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
 188
 189 int of_property_notify(int action, struct device_node *np,
 190                        struct property *prop, struct property *oldprop)
 191 {
 192         struct of_reconfig_data pr;
 193
 194         /* only call notifiers if the node is attached */
 195         if (!of_node_is_attached(np))
 196                 return 0;
 197
 198         pr.dn = np;
 199         pr.prop = prop;
 200         pr.old_prop = oldprop;
 201         return of_reconfig_notify(action, &pr);
 202 }
 203
 204 static void __of_attach_node(struct device_node *np)
 205 {
 206         const __be32 *phandle;
 207         int sz;
 208
 209         if (!of_node_check_flag(np, OF_OVERLAY)) {
 210                 np->name = __of_get_property(np, "name", NULL);
 211                 if (!np->name)
 212                         np->name = "<NULL>";
 213
 214                 phandle = __of_get_property(np, "phandle", &sz);
 215                 if (!phandle)
 216                         phandle = __of_get_property(np, "linux,phandle", &sz);
 217                 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
 218                         phandle = __of_get_property(np, "ibm,phandle", &sz);
 219                 if (phandle && (sz >= 4))
 220                         np->phandle = be32_to_cpup(phandle);
 221                 else
 222                         np->phandle = 0;
 223         }
 224
 225         np->child = NULL;
 226         np->sibling = np->parent->child;
 227         np->parent->child = np;
 228         of_node_clear_flag(np, OF_DETACHED);
 229 }
 230
 231 /**
 232  * of_attach_node() - Plug a device node into the tree and global list.
 233  * @np:         Pointer to the caller's Device Node
 234  */
 235 int of_attach_node(struct device_node *np)
 236 {
 237         struct of_reconfig_data rd;
 238         unsigned long flags;
 239
 240         memset(&rd, 0, sizeof(rd));
 241         rd.dn = np;
 242
 243         mutex_lock(&of_mutex);
 244         raw_spin_lock_irqsave(&devtree_lock, flags);
 245         __of_attach_node(np);
 246         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 247
 248         __of_attach_node_sysfs(np);
 249         mutex_unlock(&of_mutex);
 250
 251         of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
 252
 253         return 0;
 254 }
 255
 256 void __of_detach_node(struct device_node *np)
 257 {
 258         struct device_node *parent;
 259
 260         if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
 261                 return;
 262
 263         parent = np->parent;
 264         if (WARN_ON(!parent))
 265                 return;
 266
 267         if (parent->child == np)
 268                 parent->child = np->sibling;
 269         else {
 270                 struct device_node *prevsib;
 271                 for (prevsib = np->parent->child;
 272                      prevsib->sibling != np;
 273                      prevsib = prevsib->sibling)
 274                         ;
 275                 prevsib->sibling = np->sibling;
 276         }
 277
 278         of_node_set_flag(np, OF_DETACHED);
 279
 280         /* race with of_find_node_by_phandle() prevented by devtree_lock */
 281         __of_phandle_cache_inv_entry(np->phandle);
 282 }
 283
 284 /**
 285  * of_detach_node() - "Unplug" a node from the device tree.
 286  * @np:         Pointer to the caller's Device Node
 287  */
 288 int of_detach_node(struct device_node *np)
 289 {
 290         struct of_reconfig_data rd;
 291         unsigned long flags;
 292
 293         memset(&rd, 0, sizeof(rd));
 294         rd.dn = np;
 295
 296         mutex_lock(&of_mutex);
 297         raw_spin_lock_irqsave(&devtree_lock, flags);
 298         __of_detach_node(np);
 299         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 300
 301         __of_detach_node_sysfs(np);
 302         mutex_unlock(&of_mutex);
 303
 304         of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
 305
 306         return 0;
 307 }
 308 EXPORT_SYMBOL_GPL(of_detach_node);
 309
 310 static void property_list_free(struct property *prop_list)
 311 {
 312         struct property *prop, *next;
 313
 314         for (prop = prop_list; prop != NULL; prop = next) {
 315                 next = prop->next;
 316                 kfree(prop->name);
 317                 kfree(prop->value);
 318                 kfree(prop);
 319         }
 320 }
 321
 322 /**
 323  * of_node_release() - release a dynamically allocated node
 324  * @kobj: kernel object of the node to be released
 325  *
 326  * In of_node_put() this function is passed to kref_put() as the destructor.
 327  */
 328 void of_node_release(struct kobject *kobj)
 329 {
 330         struct device_node *node = kobj_to_device_node(kobj);
 331
 332         /*
 333          * can not use '"%pOF", node' in pr_err() calls from this function
 334          * because an of_node_get(node) when refcount is already zero
 335          * will result in an error and a stack dump
 336          */
 337
 338         /* We should never be releasing nodes that haven't been detached. */
 339         if (!of_node_check_flag(node, OF_DETACHED)) {
 340
 341                 pr_err("ERROR: %s() detected bad of_node_put() on %pOF/%s\n",
 342                         __func__, node->parent, node->full_name);
 343
 344                 /*
 345                  * of unittests will test this path.  Do not print the stack
 346                  * trace when the error is caused by unittest so that we do
 347                  * not display what a normal developer might reasonably
 348                  * consider a real bug.
 349                  */
 350                 if (!IS_ENABLED(CONFIG_OF_UNITTEST) ||
 351                     strcmp(node->parent->full_name, "testcase-data")) {
 352                         dump_stack();
 353                         pr_err("ERROR: next of_node_put() on this node will result in a kobject warning 'refcount_t: underflow; use-after-free.'\n");
 354                 }
 355
 356                 return;
 357         }
 358         if (!of_node_check_flag(node, OF_DYNAMIC))
 359                 return;
 360
 361         if (of_node_check_flag(node, OF_OVERLAY)) {
 362
 363                 if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
 364                         /* premature refcount of zero, do not free memory */
 365                         pr_err("ERROR: memory leak before free overlay changeset,  %pOF\n",
 366                                node);
 367                         return;
 368                 }
 369
 370                 /*
 371                  * If node->properties non-empty then properties were added
 372                  * to this node either by different overlay that has not
 373                  * yet been removed, or by a non-overlay mechanism.
 374                  */
 375                 if (node->properties)
 376                         pr_err("ERROR: %s(), unexpected properties in %pOF\n",
 377                                __func__, node);
 378         }
 379
 380         if (node->child)
 381                 pr_err("ERROR: %s() unexpected children for %pOF/%s\n",
 382                         __func__, node->parent, node->full_name);
 383
 384         property_list_free(node->properties);
 385         property_list_free(node->deadprops);
 386         fwnode_links_purge(of_fwnode_handle(node));
 387
 388         kfree(node->full_name);
 389         kfree(node->data);
 390         kfree(node);
 391 }
 392
 393 /**
 394  * __of_prop_dup - Copy a property dynamically.
 395  * @prop:       Property to copy
 396  * @allocflags: Allocation flags (typically pass GFP_KERNEL)
 397  *
 398  * Copy a property by dynamically allocating the memory of both the
 399  * property structure and the property name & contents. The property's
 400  * flags have the OF_DYNAMIC bit set so that we can differentiate between
 401  * dynamically allocated properties and not.
 402  *
 403  * Return: The newly allocated property or NULL on out of memory error.
 404  */
 405 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
 406 {
 407         struct property *new;
 408
 409         new = kzalloc(sizeof(*new), allocflags);
 410         if (!new)
 411                 return NULL;
 412
 413         /*
 414          * NOTE: There is no check for zero length value.
 415          * In case of a boolean property, this will allocate a value
 416          * of zero bytes. We do this to work around the use
 417          * of of_get_property() calls on boolean values.
 418          */
 419         new->name = kstrdup(prop->name, allocflags);
 420         new->value = kmemdup(prop->value, prop->length, allocflags);
 421         new->length = prop->length;
 422         if (!new->name || !new->value)
 423                 goto err_free;
 424
 425         /* mark the property as dynamic */
 426         of_property_set_flag(new, OF_DYNAMIC);
 427
 428         return new;
 429
 430  err_free:
 431         kfree(new->name);
 432         kfree(new->value);
 433         kfree(new);
 434         return NULL;
 435 }
 436
 437 /**
 438  * __of_node_dup() - Duplicate or create an empty device node dynamically.
 439  * @np:         if not NULL, contains properties to be duplicated in new node
 440  * @full_name:  string value to be duplicated into new node's full_name field
 441  *
 442  * Create a device tree node, optionally duplicating the properties of
 443  * another node.  The node data are dynamically allocated and all the node
 444  * flags have the OF_DYNAMIC & OF_DETACHED bits set.
 445  *
 446  * Return: The newly allocated node or NULL on out of memory error.  Use
 447  * of_node_put() on it when done to free the memory allocated for it.
 448  */
 449 struct device_node *__of_node_dup(const struct device_node *np,
 450                                   const char *full_name)
 451 {
 452         struct device_node *node;
 453
 454         node = kzalloc(sizeof(*node), GFP_KERNEL);
 455         if (!node)
 456                 return NULL;
 457         node->full_name = kstrdup(full_name, GFP_KERNEL);
 458         if (!node->full_name) {
 459                 kfree(node);
 460                 return NULL;
 461         }
 462
 463         of_node_set_flag(node, OF_DYNAMIC);
 464         of_node_set_flag(node, OF_DETACHED);
 465         of_node_init(node);
 466
 467         /* Iterate over and duplicate all properties */
 468         if (np) {
 469                 struct property *pp, *new_pp;
 470                 for_each_property_of_node(np, pp) {
 471                         new_pp = __of_prop_dup(pp, GFP_KERNEL);
 472                         if (!new_pp)
 473                                 goto err_prop;
 474                         if (__of_add_property(node, new_pp)) {
 475                                 kfree(new_pp->name);
 476                                 kfree(new_pp->value);
 477                                 kfree(new_pp);
 478                                 goto err_prop;
 479                         }
 480                 }
 481         }
 482         return node;
 483
 484  err_prop:
 485         of_node_put(node); /* Frees the node and properties */
 486         return NULL;
 487 }
 488
 489 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 490 {
 491         if (ce->action == OF_RECONFIG_ATTACH_NODE &&
 492             of_node_check_flag(ce->np, OF_OVERLAY)) {
 493                 if (kref_read(&ce->np->kobj.kref) > 1) {
 494                         pr_err("ERROR: memory leak, expected refcount 1 instead of %d, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node %pOF\n",
 495                                kref_read(&ce->np->kobj.kref), ce->np);
 496                 } else {
 497                         of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
 498                 }
 499         }
 500
 501         of_node_put(ce->np);
 502         list_del(&ce->node);
 503         kfree(ce);
 504 }
 505
 506 #ifdef DEBUG
 507 static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 508 {
 509         switch (ce->action) {
 510         case OF_RECONFIG_ADD_PROPERTY:
 511         case OF_RECONFIG_REMOVE_PROPERTY:
 512         case OF_RECONFIG_UPDATE_PROPERTY:
 513                 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
 514                         ce->np, ce->prop->name);
 515                 break;
 516         case OF_RECONFIG_ATTACH_NODE:
 517         case OF_RECONFIG_DETACH_NODE:
 518                 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
 519                         ce->np);
 520                 break;
 521         }
 522 }
 523 #else
 524 static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 525 {
 526         /* empty */
 527 }
 528 #endif
 529
 530 static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
 531                                           struct of_changeset_entry *rce)
 532 {
 533         memcpy(rce, ce, sizeof(*rce));
 534
 535         switch (ce->action) {
 536         case OF_RECONFIG_ATTACH_NODE:
 537                 rce->action = OF_RECONFIG_DETACH_NODE;
 538                 break;
 539         case OF_RECONFIG_DETACH_NODE:
 540                 rce->action = OF_RECONFIG_ATTACH_NODE;
 541                 break;
 542         case OF_RECONFIG_ADD_PROPERTY:
 543                 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 544                 break;
 545         case OF_RECONFIG_REMOVE_PROPERTY:
 546                 rce->action = OF_RECONFIG_ADD_PROPERTY;
 547                 break;
 548         case OF_RECONFIG_UPDATE_PROPERTY:
 549                 rce->old_prop = ce->prop;
 550                 rce->prop = ce->old_prop;
 551                 /* update was used but original property did not exist */
 552                 if (!rce->prop) {
 553                         rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 554                         rce->prop = ce->prop;
 555                 }
 556                 break;
 557         }
 558 }
 559
 560 static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
 561                 bool revert)
 562 {
 563         struct of_reconfig_data rd;
 564         struct of_changeset_entry ce_inverted;
 565         int ret = 0;
 566
 567         if (revert) {
 568                 __of_changeset_entry_invert(ce, &ce_inverted);
 569                 ce = &ce_inverted;
 570         }
 571
 572         switch (ce->action) {
 573         case OF_RECONFIG_ATTACH_NODE:
 574         case OF_RECONFIG_DETACH_NODE:
 575                 memset(&rd, 0, sizeof(rd));
 576                 rd.dn = ce->np;
 577                 ret = of_reconfig_notify(ce->action, &rd);
 578                 break;
 579         case OF_RECONFIG_ADD_PROPERTY:
 580         case OF_RECONFIG_REMOVE_PROPERTY:
 581         case OF_RECONFIG_UPDATE_PROPERTY:
 582                 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
 583                 break;
 584         default:
 585                 pr_err("invalid devicetree changeset action: %i\n",
 586                         (int)ce->action);
 587                 ret = -EINVAL;
 588         }
 589
 590         if (ret)
 591                 pr_err("changeset notifier error @%pOF\n", ce->np);
 592         return ret;
 593 }
 594
 595 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 596 {
 597         struct property *old_prop, **propp;
 598         unsigned long flags;
 599         int ret = 0;
 600
 601         __of_changeset_entry_dump(ce);
 602
 603         raw_spin_lock_irqsave(&devtree_lock, flags);
 604         switch (ce->action) {
 605         case OF_RECONFIG_ATTACH_NODE:
 606                 __of_attach_node(ce->np);
 607                 break;
 608         case OF_RECONFIG_DETACH_NODE:
 609                 __of_detach_node(ce->np);
 610                 break;
 611         case OF_RECONFIG_ADD_PROPERTY:
 612                 /* If the property is in deadprops then it must be removed */
 613                 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
 614                         if (*propp == ce->prop) {
 615                                 *propp = ce->prop->next;
 616                                 ce->prop->next = NULL;
 617                                 break;
 618                         }
 619                 }
 620
 621                 ret = __of_add_property(ce->np, ce->prop);
 622                 if (ret) {
 623                         pr_err("changeset: add_property failed @%pOF/%s\n",
 624                                 ce->np,
 625                                 ce->prop->name);
 626                         break;
 627                 }
 628                 break;
 629         case OF_RECONFIG_REMOVE_PROPERTY:
 630                 ret = __of_remove_property(ce->np, ce->prop);
 631                 if (ret) {
 632                         pr_err("changeset: remove_property failed @%pOF/%s\n",
 633                                 ce->np,
 634                                 ce->prop->name);
 635                         break;
 636                 }
 637                 break;
 638
 639         case OF_RECONFIG_UPDATE_PROPERTY:
 640                 /* If the property is in deadprops then it must be removed */
 641                 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
 642                         if (*propp == ce->prop) {
 643                                 *propp = ce->prop->next;
 644                                 ce->prop->next = NULL;
 645                                 break;
 646                         }
 647                 }
 648
 649                 ret = __of_update_property(ce->np, ce->prop, &old_prop);
 650                 if (ret) {
 651                         pr_err("changeset: update_property failed @%pOF/%s\n",
 652                                 ce->np,
 653                                 ce->prop->name);
 654                         break;
 655                 }
 656                 break;
 657         default:
 658                 ret = -EINVAL;
 659         }
 660         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 661
 662         if (ret)
 663                 return ret;
 664
 665         switch (ce->action) {
 666         case OF_RECONFIG_ATTACH_NODE:
 667                 __of_attach_node_sysfs(ce->np);
 668                 break;
 669         case OF_RECONFIG_DETACH_NODE:
 670                 __of_detach_node_sysfs(ce->np);
 671                 break;
 672         case OF_RECONFIG_ADD_PROPERTY:
 673                 /* ignore duplicate names */
 674                 __of_add_property_sysfs(ce->np, ce->prop);
 675                 break;
 676         case OF_RECONFIG_REMOVE_PROPERTY:
 677                 __of_remove_property_sysfs(ce->np, ce->prop);
 678                 break;
 679         case OF_RECONFIG_UPDATE_PROPERTY:
 680                 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
 681                 break;
 682         }
 683
 684         return 0;
 685 }
 686
 687 static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
 688 {
 689         struct of_changeset_entry ce_inverted;
 690
 691         __of_changeset_entry_invert(ce, &ce_inverted);
 692         return __of_changeset_entry_apply(&ce_inverted);
 693 }
 694
 695 /**
 696  * of_changeset_init - Initialize a changeset for use
 697  *
 698  * @ocs:        changeset pointer
 699  *
 700  * Initialize a changeset structure
 701  */
 702 void of_changeset_init(struct of_changeset *ocs)
 703 {
 704         memset(ocs, 0, sizeof(*ocs));
 705         INIT_LIST_HEAD(&ocs->entries);
 706 }
 707 EXPORT_SYMBOL_GPL(of_changeset_init);
 708
 709 /**
 710  * of_changeset_destroy - Destroy a changeset
 711  *
 712  * @ocs:        changeset pointer
 713  *
 714  * Destroys a changeset. Note that if a changeset is applied,
 715  * its changes to the tree cannot be reverted.
 716  */
 717 void of_changeset_destroy(struct of_changeset *ocs)
 718 {
 719         struct of_changeset_entry *ce, *cen;
 720
 721         list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
 722                 __of_changeset_entry_destroy(ce);
 723 }
 724 EXPORT_SYMBOL_GPL(of_changeset_destroy);
 725
 726 /*
 727  * Apply the changeset entries in @ocs.
 728  * If apply fails, an attempt is made to revert the entries that were
 729  * successfully applied.
 730  *
 731  * If multiple revert errors occur then only the final revert error is reported.
 732  *
 733  * Returns 0 on success, a negative error value in case of an error.
 734  * If a revert error occurs, it is returned in *ret_revert.
 735  */
 736 int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
 737 {
 738         struct of_changeset_entry *ce;
 739         int ret, ret_tmp;
 740
 741         pr_debug("changeset: applying...\n");
 742         list_for_each_entry(ce, &ocs->entries, node) {
 743                 ret = __of_changeset_entry_apply(ce);
 744                 if (ret) {
 745                         pr_err("Error applying changeset (%d)\n", ret);
 746                         list_for_each_entry_continue_reverse(ce, &ocs->entries,
 747                                                              node) {
 748                                 ret_tmp = __of_changeset_entry_revert(ce);
 749                                 if (ret_tmp)
 750                                         *ret_revert = ret_tmp;
 751                         }
 752                         return ret;
 753                 }
 754         }
 755
 756         return 0;
 757 }
 758
 759 /*
 760  * Returns 0 on success, a negative error value in case of an error.
 761  *
 762  * If multiple changeset entry notification errors occur then only the
 763  * final notification error is reported.
 764  */
 765 int __of_changeset_apply_notify(struct of_changeset *ocs)
 766 {
 767         struct of_changeset_entry *ce;
 768         int ret = 0, ret_tmp;
 769
 770         pr_debug("changeset: emitting notifiers.\n");
 771
 772         /* drop the global lock while emitting notifiers */
 773         mutex_unlock(&of_mutex);
 774         list_for_each_entry(ce, &ocs->entries, node) {
 775                 ret_tmp = __of_changeset_entry_notify(ce, 0);
 776                 if (ret_tmp)
 777                         ret = ret_tmp;
 778         }
 779         mutex_lock(&of_mutex);
 780         pr_debug("changeset: notifiers sent.\n");
 781
 782         return ret;
 783 }
 784
 785 /*
 786  * Returns 0 on success, a negative error value in case of an error.
 787  *
 788  * If a changeset entry apply fails, an attempt is made to revert any
 789  * previous entries in the changeset.  If any of the reverts fails,
 790  * that failure is not reported.  Thus the state of the device tree
 791  * is unknown if an apply error occurs.
 792  */
 793 static int __of_changeset_apply(struct of_changeset *ocs)
 794 {
 795         int ret, ret_revert = 0;
 796
 797         ret = __of_changeset_apply_entries(ocs, &ret_revert);
 798         if (!ret)
 799                 ret = __of_changeset_apply_notify(ocs);
 800
 801         return ret;
 802 }
 803
 804 /**
 805  * of_changeset_apply - Applies a changeset
 806  *
 807  * @ocs:        changeset pointer
 808  *
 809  * Applies a changeset to the live tree.
 810  * Any side-effects of live tree state changes are applied here on
 811  * success, like creation/destruction of devices and side-effects
 812  * like creation of sysfs properties and directories.
 813  *
 814  * Return: 0 on success, a negative error value in case of an error.
 815  * On error the partially applied effects are reverted.
 816  */
 817 int of_changeset_apply(struct of_changeset *ocs)
 818 {
 819         int ret;
 820
 821         mutex_lock(&of_mutex);
 822         ret = __of_changeset_apply(ocs);
 823         mutex_unlock(&of_mutex);
 824
 825         return ret;
 826 }
 827 EXPORT_SYMBOL_GPL(of_changeset_apply);
 828
 829 /*
 830  * Revert the changeset entries in @ocs.
 831  * If revert fails, an attempt is made to re-apply the entries that were
 832  * successfully removed.
 833  *
 834  * If multiple re-apply errors occur then only the final apply error is
 835  * reported.
 836  *
 837  * Returns 0 on success, a negative error value in case of an error.
 838  * If an apply error occurs, it is returned in *ret_apply.
 839  */
 840 int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
 841 {
 842         struct of_changeset_entry *ce;
 843         int ret, ret_tmp;
 844
 845         pr_debug("changeset: reverting...\n");
 846         list_for_each_entry_reverse(ce, &ocs->entries, node) {
 847                 ret = __of_changeset_entry_revert(ce);
 848                 if (ret) {
 849                         pr_err("Error reverting changeset (%d)\n", ret);
 850                         list_for_each_entry_continue(ce, &ocs->entries, node) {
 851                                 ret_tmp = __of_changeset_entry_apply(ce);
 852                                 if (ret_tmp)
 853                                         *ret_apply = ret_tmp;
 854                         }
 855                         return ret;
 856                 }
 857         }
 858
 859         return 0;
 860 }
 861
 862 /*
 863  * If multiple changeset entry notification errors occur then only the
 864  * final notification error is reported.
 865  */
 866 int __of_changeset_revert_notify(struct of_changeset *ocs)
 867 {
 868         struct of_changeset_entry *ce;
 869         int ret = 0, ret_tmp;
 870
 871         pr_debug("changeset: emitting notifiers.\n");
 872
 873         /* drop the global lock while emitting notifiers */
 874         mutex_unlock(&of_mutex);
 875         list_for_each_entry_reverse(ce, &ocs->entries, node) {
 876                 ret_tmp = __of_changeset_entry_notify(ce, 1);
 877                 if (ret_tmp)
 878                         ret = ret_tmp;
 879         }
 880         mutex_lock(&of_mutex);
 881         pr_debug("changeset: notifiers sent.\n");
 882
 883         return ret;
 884 }
 885
 886 static int __of_changeset_revert(struct of_changeset *ocs)
 887 {
 888         int ret, ret_reply;
 889
 890         ret_reply = 0;
 891         ret = __of_changeset_revert_entries(ocs, &ret_reply);
 892
 893         if (!ret)
 894                 ret = __of_changeset_revert_notify(ocs);
 895
 896         return ret;
 897 }
 898
 899 /**
 900  * of_changeset_revert - Reverts an applied changeset
 901  *
 902  * @ocs:        changeset pointer
 903  *
 904  * Reverts a changeset returning the state of the tree to what it
 905  * was before the application.
 906  * Any side-effects like creation/destruction of devices and
 907  * removal of sysfs properties and directories are applied.
 908  *
 909  * Return: 0 on success, a negative error value in case of an error.
 910  */
 911 int of_changeset_revert(struct of_changeset *ocs)
 912 {
 913         int ret;
 914
 915         mutex_lock(&of_mutex);
 916         ret = __of_changeset_revert(ocs);
 917         mutex_unlock(&of_mutex);
 918
 919         return ret;
 920 }
 921 EXPORT_SYMBOL_GPL(of_changeset_revert);
 922
 923 /**
 924  * of_changeset_action - Add an action to the tail of the changeset list
 925  *
 926  * @ocs:        changeset pointer
 927  * @action:     action to perform
 928  * @np:         Pointer to device node
 929  * @prop:       Pointer to property
 930  *
 931  * On action being one of:
 932  * + OF_RECONFIG_ATTACH_NODE
 933  * + OF_RECONFIG_DETACH_NODE,
 934  * + OF_RECONFIG_ADD_PROPERTY
 935  * + OF_RECONFIG_REMOVE_PROPERTY,
 936  * + OF_RECONFIG_UPDATE_PROPERTY
 937  *
 938  * Return: 0 on success, a negative error value in case of an error.
 939  */
 940 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 941                 struct device_node *np, struct property *prop)
 942 {
 943         struct of_changeset_entry *ce;
 944
 945         ce = kzalloc(sizeof(*ce), GFP_KERNEL);
 946         if (!ce)
 947                 return -ENOMEM;
 948
 949         /* get a reference to the node */
 950         ce->action = action;
 951         ce->np = of_node_get(np);
 952         ce->prop = prop;
 953
 954         if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
 955                 ce->old_prop = of_find_property(np, prop->name, NULL);
 956
 957         /* add it to the list */
 958         list_add_tail(&ce->node, &ocs->entries);
 959         return 0;
 960 }
 961 EXPORT_SYMBOL_GPL(of_changeset_action);