drivers/of/dynamic.c

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