drivers/of/base.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
of_node_name_eq
of_node_name_prefix
__of_node_is_type
of_n_addr_cells
of_n_size_cells
of_node_to_nid
__of_free_phandle_cache
of_free_phandle_cache
__of_free_phandle_cache_entry
of_populate_phandle_cache
of_core_init
__of_find_property
of_find_property
__of_find_all_nodes
of_find_all_nodes
__of_get_property
of_get_property
arch_match_cpu_phys_id
__of_find_n_match_cpu_property
arch_find_n_match_cpu_physical_id
of_get_cpu_node
of_cpu_node_to_id
__of_device_is_compatible
of_device_is_compatible
of_device_compatible_match
of_machine_is_compatible
__of_device_is_available
of_device_is_available
of_device_is_big_endian
of_get_parent
of_get_next_parent
__of_get_next_child
of_get_next_child
of_get_next_available_child
of_get_next_cpu_node
of_get_compatible_child
of_get_child_by_name
__of_find_node_by_path
__of_find_node_by_full_path
of_find_node_opts_by_path
of_find_node_by_name
of_find_node_by_type
of_find_compatible_node
of_find_node_with_property
__of_match_node
of_match_node
of_find_matching_node_and_match
of_modalias_node
of_find_node_by_phandle
of_print_phandle_args
of_phandle_iterator_init
of_phandle_iterator_next
of_phandle_iterator_args
__of_parse_phandle_with_args
of_parse_phandle
of_parse_phandle_with_args
of_parse_phandle_with_args_map
of_parse_phandle_with_fixed_args
of_count_phandle_with_args
__of_add_property
of_add_property
__of_remove_property
of_remove_property
__of_update_property
of_update_property
of_alias_add
of_alias_scan
of_alias_get_id
of_alias_get_alias_list
of_alias_get_highest_id
of_console_check
of_find_next_cache_node
of_find_last_cache_level
of_map_rid
   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Procedures for creating, accessing and interpreting the device tree.
   4  *
   5  * Paul Mackerras       August 1996.
   6  * Copyright (C) 1996-2005 Paul Mackerras.
   7  *
   8  *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
   9  *    {engebret|bergner}@us.ibm.com
  10  *
  11  *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
  12  *
  13  *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
  14  *  Grant Likely.
  15  */
  16 
  17 #define pr_fmt(fmt)     "OF: " fmt
  18 
  19 #include <linux/bitmap.h>
  20 #include <linux/console.h>
  21 #include <linux/ctype.h>
  22 #include <linux/cpu.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_graph.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/slab.h>
  29 #include <linux/string.h>
  30 #include <linux/proc_fs.h>
  31 
  32 #include "of_private.h"
  33 
  34 LIST_HEAD(aliases_lookup);
  35 
  36 struct device_node *of_root;
  37 EXPORT_SYMBOL(of_root);
  38 struct device_node *of_chosen;
  39 struct device_node *of_aliases;
  40 struct device_node *of_stdout;
  41 static const char *of_stdout_options;
  42 
  43 struct kset *of_kset;
  44 
  45 /*
  46  * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
  47  * This mutex must be held whenever modifications are being made to the
  48  * device tree. The of_{attach,detach}_node() and
  49  * of_{add,remove,update}_property() helpers make sure this happens.
  50  */
  51 DEFINE_MUTEX(of_mutex);
  52 
  53 /* use when traversing tree through the child, sibling,
  54  * or parent members of struct device_node.
  55  */
  56 DEFINE_RAW_SPINLOCK(devtree_lock);
  57 
  58 bool of_node_name_eq(const struct device_node *np, const char *name)
  59 {
  60         const char *node_name;
  61         size_t len;
  62 
  63         if (!np)
  64                 return false;
  65 
  66         node_name = kbasename(np->full_name);
  67         len = strchrnul(node_name, '@') - node_name;
  68 
  69         return (strlen(name) == len) && (strncmp(node_name, name, len) == 0);
  70 }
  71 EXPORT_SYMBOL(of_node_name_eq);
  72 
  73 bool of_node_name_prefix(const struct device_node *np, const char *prefix)
  74 {
  75         if (!np)
  76                 return false;
  77 
  78         return strncmp(kbasename(np->full_name), prefix, strlen(prefix)) == 0;
  79 }
  80 EXPORT_SYMBOL(of_node_name_prefix);
  81 
  82 static bool __of_node_is_type(const struct device_node *np, const char *type)
  83 {
  84         const char *match = __of_get_property(np, "device_type", NULL);
  85 
  86         return np && match && type && !strcmp(match, type);
  87 }
  88 
  89 int of_n_addr_cells(struct device_node *np)
  90 {
  91         u32 cells;
  92 
  93         do {
  94                 if (np->parent)
  95                         np = np->parent;
  96                 if (!of_property_read_u32(np, "#address-cells", &cells))
  97                         return cells;
  98         } while (np->parent);
  99         /* No #address-cells property for the root node */
 100         return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
 101 }
 102 EXPORT_SYMBOL(of_n_addr_cells);
 103 
 104 int of_n_size_cells(struct device_node *np)
 105 {
 106         u32 cells;
 107 
 108         do {
 109                 if (np->parent)
 110                         np = np->parent;
 111                 if (!of_property_read_u32(np, "#size-cells", &cells))
 112                         return cells;
 113         } while (np->parent);
 114         /* No #size-cells property for the root node */
 115         return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
 116 }
 117 EXPORT_SYMBOL(of_n_size_cells);
 118 
 119 #ifdef CONFIG_NUMA
 120 int __weak of_node_to_nid(struct device_node *np)
 121 {
 122         return NUMA_NO_NODE;
 123 }
 124 #endif
 125 
 126 /*
 127  * Assumptions behind phandle_cache implementation:
 128  *   - phandle property values are in a contiguous range of 1..n
 129  *
 130  * If the assumptions do not hold, then
 131  *   - the phandle lookup overhead reduction provided by the cache
 132  *     will likely be less
 133  */
 134 
 135 static struct device_node **phandle_cache;
 136 static u32 phandle_cache_mask;
 137 
 138 /*
 139  * Caller must hold devtree_lock.
 140  */
 141 static void __of_free_phandle_cache(void)
 142 {
 143         u32 cache_entries = phandle_cache_mask + 1;
 144         u32 k;
 145 
 146         if (!phandle_cache)
 147                 return;
 148 
 149         for (k = 0; k < cache_entries; k++)
 150                 of_node_put(phandle_cache[k]);
 151 
 152         kfree(phandle_cache);
 153         phandle_cache = NULL;
 154 }
 155 
 156 int of_free_phandle_cache(void)
 157 {
 158         unsigned long flags;
 159 
 160         raw_spin_lock_irqsave(&devtree_lock, flags);
 161 
 162         __of_free_phandle_cache();
 163 
 164         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 165 
 166         return 0;
 167 }
 168 #if !defined(CONFIG_MODULES)
 169 late_initcall_sync(of_free_phandle_cache);
 170 #endif
 171 
 172 /*
 173  * Caller must hold devtree_lock.
 174  */
 175 void __of_free_phandle_cache_entry(phandle handle)
 176 {
 177         phandle masked_handle;
 178         struct device_node *np;
 179 
 180         if (!handle)
 181                 return;
 182 
 183         masked_handle = handle & phandle_cache_mask;
 184 
 185         if (phandle_cache) {
 186                 np = phandle_cache[masked_handle];
 187                 if (np && handle == np->phandle) {
 188                         of_node_put(np);
 189                         phandle_cache[masked_handle] = NULL;
 190                 }
 191         }
 192 }
 193 
 194 void of_populate_phandle_cache(void)
 195 {
 196         unsigned long flags;
 197         u32 cache_entries;
 198         struct device_node *np;
 199         u32 phandles = 0;
 200 
 201         raw_spin_lock_irqsave(&devtree_lock, flags);
 202 
 203         __of_free_phandle_cache();
 204 
 205         for_each_of_allnodes(np)
 206                 if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
 207                         phandles++;
 208 
 209         if (!phandles)
 210                 goto out;
 211 
 212         cache_entries = roundup_pow_of_two(phandles);
 213         phandle_cache_mask = cache_entries - 1;
 214 
 215         phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
 216                                 GFP_ATOMIC);
 217         if (!phandle_cache)
 218                 goto out;
 219 
 220         for_each_of_allnodes(np)
 221                 if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) {
 222                         of_node_get(np);
 223                         phandle_cache[np->phandle & phandle_cache_mask] = np;
 224                 }
 225 
 226 out:
 227         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 228 }
 229 
 230 void __init of_core_init(void)
 231 {
 232         struct device_node *np;
 233 
 234         of_populate_phandle_cache();
 235 
 236         /* Create the kset, and register existing nodes */
 237         mutex_lock(&of_mutex);
 238         of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
 239         if (!of_kset) {
 240                 mutex_unlock(&of_mutex);
 241                 pr_err("failed to register existing nodes\n");
 242                 return;
 243         }
 244         for_each_of_allnodes(np)
 245                 __of_attach_node_sysfs(np);
 246         mutex_unlock(&of_mutex);
 247 
 248         /* Symlink in /proc as required by userspace ABI */
 249         if (of_root)
 250                 proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
 251 }
 252 
 253 static struct property *__of_find_property(const struct device_node *np,
 254                                            const char *name, int *lenp)
 255 {
 256         struct property *pp;
 257 
 258         if (!np)
 259                 return NULL;
 260 
 261         for (pp = np->properties; pp; pp = pp->next) {
 262                 if (of_prop_cmp(pp->name, name) == 0) {
 263                         if (lenp)
 264                                 *lenp = pp->length;
 265                         break;
 266                 }
 267         }
 268 
 269         return pp;
 270 }
 271 
 272 struct property *of_find_property(const struct device_node *np,
 273                                   const char *name,
 274                                   int *lenp)
 275 {
 276         struct property *pp;
 277         unsigned long flags;
 278 
 279         raw_spin_lock_irqsave(&devtree_lock, flags);
 280         pp = __of_find_property(np, name, lenp);
 281         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 282 
 283         return pp;
 284 }
 285 EXPORT_SYMBOL(of_find_property);
 286 
 287 struct device_node *__of_find_all_nodes(struct device_node *prev)
 288 {
 289         struct device_node *np;
 290         if (!prev) {
 291                 np = of_root;
 292         } else if (prev->child) {
 293                 np = prev->child;
 294         } else {
 295                 /* Walk back up looking for a sibling, or the end of the structure */
 296                 np = prev;
 297                 while (np->parent && !np->sibling)
 298                         np = np->parent;
 299                 np = np->sibling; /* Might be null at the end of the tree */
 300         }
 301         return np;
 302 }
 303 
 304 /**
 305  * of_find_all_nodes - Get next node in global list
 306  * @prev:       Previous node or NULL to start iteration
 307  *              of_node_put() will be called on it
 308  *
 309  * Returns a node pointer with refcount incremented, use
 310  * of_node_put() on it when done.
 311  */
 312 struct device_node *of_find_all_nodes(struct device_node *prev)
 313 {
 314         struct device_node *np;
 315         unsigned long flags;
 316 
 317         raw_spin_lock_irqsave(&devtree_lock, flags);
 318         np = __of_find_all_nodes(prev);
 319         of_node_get(np);
 320         of_node_put(prev);
 321         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 322         return np;
 323 }
 324 EXPORT_SYMBOL(of_find_all_nodes);
 325 
 326 /*
 327  * Find a property with a given name for a given node
 328  * and return the value.
 329  */
 330 const void *__of_get_property(const struct device_node *np,
 331                               const char *name, int *lenp)
 332 {
 333         struct property *pp = __of_find_property(np, name, lenp);
 334 
 335         return pp ? pp->value : NULL;
 336 }
 337 
 338 /*
 339  * Find a property with a given name for a given node
 340  * and return the value.
 341  */
 342 const void *of_get_property(const struct device_node *np, const char *name,
 343                             int *lenp)
 344 {
 345         struct property *pp = of_find_property(np, name, lenp);
 346 
 347         return pp ? pp->value : NULL;
 348 }
 349 EXPORT_SYMBOL(of_get_property);
 350 
 351 /*
 352  * arch_match_cpu_phys_id - Match the given logical CPU and physical id
 353  *
 354  * @cpu: logical cpu index of a core/thread
 355  * @phys_id: physical identifier of a core/thread
 356  *
 357  * CPU logical to physical index mapping is architecture specific.
 358  * However this __weak function provides a default match of physical
 359  * id to logical cpu index. phys_id provided here is usually values read
 360  * from the device tree which must match the hardware internal registers.
 361  *
 362  * Returns true if the physical identifier and the logical cpu index
 363  * correspond to the same core/thread, false otherwise.
 364  */
 365 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
 366 {
 367         return (u32)phys_id == cpu;
 368 }
 369 
 370 /**
 371  * Checks if the given "prop_name" property holds the physical id of the
 372  * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
 373  * NULL, local thread number within the core is returned in it.
 374  */
 375 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
 376                         const char *prop_name, int cpu, unsigned int *thread)
 377 {
 378         const __be32 *cell;
 379         int ac, prop_len, tid;
 380         u64 hwid;
 381 
 382         ac = of_n_addr_cells(cpun);
 383         cell = of_get_property(cpun, prop_name, &prop_len);
 384         if (!cell && !ac && arch_match_cpu_phys_id(cpu, 0))
 385                 return true;
 386         if (!cell || !ac)
 387                 return false;
 388         prop_len /= sizeof(*cell) * ac;
 389         for (tid = 0; tid < prop_len; tid++) {
 390                 hwid = of_read_number(cell, ac);
 391                 if (arch_match_cpu_phys_id(cpu, hwid)) {
 392                         if (thread)
 393                                 *thread = tid;
 394                         return true;
 395                 }
 396                 cell += ac;
 397         }
 398         return false;
 399 }
 400 
 401 /*
 402  * arch_find_n_match_cpu_physical_id - See if the given device node is
 403  * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
 404  * else false.  If 'thread' is non-NULL, the local thread number within the
 405  * core is returned in it.
 406  */
 407 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
 408                                               int cpu, unsigned int *thread)
 409 {
 410         /* Check for non-standard "ibm,ppc-interrupt-server#s" property
 411          * for thread ids on PowerPC. If it doesn't exist fallback to
 412          * standard "reg" property.
 413          */
 414         if (IS_ENABLED(CONFIG_PPC) &&
 415             __of_find_n_match_cpu_property(cpun,
 416                                            "ibm,ppc-interrupt-server#s",
 417                                            cpu, thread))
 418                 return true;
 419 
 420         return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
 421 }
 422 
 423 /**
 424  * of_get_cpu_node - Get device node associated with the given logical CPU
 425  *
 426  * @cpu: CPU number(logical index) for which device node is required
 427  * @thread: if not NULL, local thread number within the physical core is
 428  *          returned
 429  *
 430  * The main purpose of this function is to retrieve the device node for the
 431  * given logical CPU index. It should be used to initialize the of_node in
 432  * cpu device. Once of_node in cpu device is populated, all the further
 433  * references can use that instead.
 434  *
 435  * CPU logical to physical index mapping is architecture specific and is built
 436  * before booting secondary cores. This function uses arch_match_cpu_phys_id
 437  * which can be overridden by architecture specific implementation.
 438  *
 439  * Returns a node pointer for the logical cpu with refcount incremented, use
 440  * of_node_put() on it when done. Returns NULL if not found.
 441  */
 442 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
 443 {
 444         struct device_node *cpun;
 445 
 446         for_each_of_cpu_node(cpun) {
 447                 if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
 448                         return cpun;
 449         }
 450         return NULL;
 451 }
 452 EXPORT_SYMBOL(of_get_cpu_node);
 453 
 454 /**
 455  * of_cpu_node_to_id: Get the logical CPU number for a given device_node
 456  *
 457  * @cpu_node: Pointer to the device_node for CPU.
 458  *
 459  * Returns the logical CPU number of the given CPU device_node.
 460  * Returns -ENODEV if the CPU is not found.
 461  */
 462 int of_cpu_node_to_id(struct device_node *cpu_node)
 463 {
 464         int cpu;
 465         bool found = false;
 466         struct device_node *np;
 467 
 468         for_each_possible_cpu(cpu) {
 469                 np = of_cpu_device_node_get(cpu);
 470                 found = (cpu_node == np);
 471                 of_node_put(np);
 472                 if (found)
 473                         return cpu;
 474         }
 475 
 476         return -ENODEV;
 477 }
 478 EXPORT_SYMBOL(of_cpu_node_to_id);
 479 
 480 /**
 481  * __of_device_is_compatible() - Check if the node matches given constraints
 482  * @device: pointer to node
 483  * @compat: required compatible string, NULL or "" for any match
 484  * @type: required device_type value, NULL or "" for any match
 485  * @name: required node name, NULL or "" for any match
 486  *
 487  * Checks if the given @compat, @type and @name strings match the
 488  * properties of the given @device. A constraints can be skipped by
 489  * passing NULL or an empty string as the constraint.
 490  *
 491  * Returns 0 for no match, and a positive integer on match. The return
 492  * value is a relative score with larger values indicating better
 493  * matches. The score is weighted for the most specific compatible value
 494  * to get the highest score. Matching type is next, followed by matching
 495  * name. Practically speaking, this results in the following priority
 496  * order for matches:
 497  *
 498  * 1. specific compatible && type && name
 499  * 2. specific compatible && type
 500  * 3. specific compatible && name
 501  * 4. specific compatible
 502  * 5. general compatible && type && name
 503  * 6. general compatible && type
 504  * 7. general compatible && name
 505  * 8. general compatible
 506  * 9. type && name
 507  * 10. type
 508  * 11. name
 509  */
 510 static int __of_device_is_compatible(const struct device_node *device,
 511                                      const char *compat, const char *type, const char *name)
 512 {
 513         struct property *prop;
 514         const char *cp;
 515         int index = 0, score = 0;
 516 
 517         /* Compatible match has highest priority */
 518         if (compat && compat[0]) {
 519                 prop = __of_find_property(device, "compatible", NULL);
 520                 for (cp = of_prop_next_string(prop, NULL); cp;
 521                      cp = of_prop_next_string(prop, cp), index++) {
 522                         if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
 523                                 score = INT_MAX/2 - (index << 2);
 524                                 break;
 525                         }
 526                 }
 527                 if (!score)
 528                         return 0;
 529         }
 530 
 531         /* Matching type is better than matching name */
 532         if (type && type[0]) {
 533                 if (!__of_node_is_type(device, type))
 534                         return 0;
 535                 score += 2;
 536         }
 537 
 538         /* Matching name is a bit better than not */
 539         if (name && name[0]) {
 540                 if (!of_node_name_eq(device, name))
 541                         return 0;
 542                 score++;
 543         }
 544 
 545         return score;
 546 }
 547 
 548 /** Checks if the given "compat" string matches one of the strings in
 549  * the device's "compatible" property
 550  */
 551 int of_device_is_compatible(const struct device_node *device,
 552                 const char *compat)
 553 {
 554         unsigned long flags;
 555         int res;
 556 
 557         raw_spin_lock_irqsave(&devtree_lock, flags);
 558         res = __of_device_is_compatible(device, compat, NULL, NULL);
 559         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 560         return res;
 561 }
 562 EXPORT_SYMBOL(of_device_is_compatible);
 563 
 564 /** Checks if the device is compatible with any of the entries in
 565  *  a NULL terminated array of strings. Returns the best match
 566  *  score or 0.
 567  */
 568 int of_device_compatible_match(struct device_node *device,
 569                                const char *const *compat)
 570 {
 571         unsigned int tmp, score = 0;
 572 
 573         if (!compat)
 574                 return 0;
 575 
 576         while (*compat) {
 577                 tmp = of_device_is_compatible(device, *compat);
 578                 if (tmp > score)
 579                         score = tmp;
 580                 compat++;
 581         }
 582 
 583         return score;
 584 }
 585 
 586 /**
 587  * of_machine_is_compatible - Test root of device tree for a given compatible value
 588  * @compat: compatible string to look for in root node's compatible property.
 589  *
 590  * Returns a positive integer if the root node has the given value in its
 591  * compatible property.
 592  */
 593 int of_machine_is_compatible(const char *compat)
 594 {
 595         struct device_node *root;
 596         int rc = 0;
 597 
 598         root = of_find_node_by_path("/");
 599         if (root) {
 600                 rc = of_device_is_compatible(root, compat);
 601                 of_node_put(root);
 602         }
 603         return rc;
 604 }
 605 EXPORT_SYMBOL(of_machine_is_compatible);
 606 
 607 /**
 608  *  __of_device_is_available - check if a device is available for use
 609  *
 610  *  @device: Node to check for availability, with locks already held
 611  *
 612  *  Returns true if the status property is absent or set to "okay" or "ok",
 613  *  false otherwise
 614  */
 615 static bool __of_device_is_available(const struct device_node *device)
 616 {
 617         const char *status;
 618         int statlen;
 619 
 620         if (!device)
 621                 return false;
 622 
 623         status = __of_get_property(device, "status", &statlen);
 624         if (status == NULL)
 625                 return true;
 626 
 627         if (statlen > 0) {
 628                 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
 629                         return true;
 630         }
 631 
 632         return false;
 633 }
 634 
 635 /**
 636  *  of_device_is_available - check if a device is available for use
 637  *
 638  *  @device: Node to check for availability
 639  *
 640  *  Returns true if the status property is absent or set to "okay" or "ok",
 641  *  false otherwise
 642  */
 643 bool of_device_is_available(const struct device_node *device)
 644 {
 645         unsigned long flags;
 646         bool res;
 647 
 648         raw_spin_lock_irqsave(&devtree_lock, flags);
 649         res = __of_device_is_available(device);
 650         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 651         return res;
 652 
 653 }
 654 EXPORT_SYMBOL(of_device_is_available);
 655 
 656 /**
 657  *  of_device_is_big_endian - check if a device has BE registers
 658  *
 659  *  @device: Node to check for endianness
 660  *
 661  *  Returns true if the device has a "big-endian" property, or if the kernel
 662  *  was compiled for BE *and* the device has a "native-endian" property.
 663  *  Returns false otherwise.
 664  *
 665  *  Callers would nominally use ioread32be/iowrite32be if
 666  *  of_device_is_big_endian() == true, or readl/writel otherwise.
 667  */
 668 bool of_device_is_big_endian(const struct device_node *device)
 669 {
 670         if (of_property_read_bool(device, "big-endian"))
 671                 return true;
 672         if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
 673             of_property_read_bool(device, "native-endian"))
 674                 return true;
 675         return false;
 676 }
 677 EXPORT_SYMBOL(of_device_is_big_endian);
 678 
 679 /**
 680  *      of_get_parent - Get a node's parent if any
 681  *      @node:  Node to get parent
 682  *
 683  *      Returns a node pointer with refcount incremented, use
 684  *      of_node_put() on it when done.
 685  */
 686 struct device_node *of_get_parent(const struct device_node *node)
 687 {
 688         struct device_node *np;
 689         unsigned long flags;
 690 
 691         if (!node)
 692                 return NULL;
 693 
 694         raw_spin_lock_irqsave(&devtree_lock, flags);
 695         np = of_node_get(node->parent);
 696         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 697         return np;
 698 }
 699 EXPORT_SYMBOL(of_get_parent);
 700 
 701 /**
 702  *      of_get_next_parent - Iterate to a node's parent
 703  *      @node:  Node to get parent of
 704  *
 705  *      This is like of_get_parent() except that it drops the
 706  *      refcount on the passed node, making it suitable for iterating
 707  *      through a node's parents.
 708  *
 709  *      Returns a node pointer with refcount incremented, use
 710  *      of_node_put() on it when done.
 711  */
 712 struct device_node *of_get_next_parent(struct device_node *node)
 713 {
 714         struct device_node *parent;
 715         unsigned long flags;
 716 
 717         if (!node)
 718                 return NULL;
 719 
 720         raw_spin_lock_irqsave(&devtree_lock, flags);
 721         parent = of_node_get(node->parent);
 722         of_node_put(node);
 723         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 724         return parent;
 725 }
 726 EXPORT_SYMBOL(of_get_next_parent);
 727 
 728 static struct device_node *__of_get_next_child(const struct device_node *node,
 729                                                 struct device_node *prev)
 730 {
 731         struct device_node *next;
 732 
 733         if (!node)
 734                 return NULL;
 735 
 736         next = prev ? prev->sibling : node->child;
 737         for (; next; next = next->sibling)
 738                 if (of_node_get(next))
 739                         break;
 740         of_node_put(prev);
 741         return next;
 742 }
 743 #define __for_each_child_of_node(parent, child) \
 744         for (child = __of_get_next_child(parent, NULL); child != NULL; \
 745              child = __of_get_next_child(parent, child))
 746 
 747 /**
 748  *      of_get_next_child - Iterate a node childs
 749  *      @node:  parent node
 750  *      @prev:  previous child of the parent node, or NULL to get first
 751  *
 752  *      Returns a node pointer with refcount incremented, use of_node_put() on
 753  *      it when done. Returns NULL when prev is the last child. Decrements the
 754  *      refcount of prev.
 755  */
 756 struct device_node *of_get_next_child(const struct device_node *node,
 757         struct device_node *prev)
 758 {
 759         struct device_node *next;
 760         unsigned long flags;
 761 
 762         raw_spin_lock_irqsave(&devtree_lock, flags);
 763         next = __of_get_next_child(node, prev);
 764         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 765         return next;
 766 }
 767 EXPORT_SYMBOL(of_get_next_child);
 768 
 769 /**
 770  *      of_get_next_available_child - Find the next available child node
 771  *      @node:  parent node
 772  *      @prev:  previous child of the parent node, or NULL to get first
 773  *
 774  *      This function is like of_get_next_child(), except that it
 775  *      automatically skips any disabled nodes (i.e. status = "disabled").
 776  */
 777 struct device_node *of_get_next_available_child(const struct device_node *node,
 778         struct device_node *prev)
 779 {
 780         struct device_node *next;
 781         unsigned long flags;
 782 
 783         if (!node)
 784                 return NULL;
 785 
 786         raw_spin_lock_irqsave(&devtree_lock, flags);
 787         next = prev ? prev->sibling : node->child;
 788         for (; next; next = next->sibling) {
 789                 if (!__of_device_is_available(next))
 790                         continue;
 791                 if (of_node_get(next))
 792                         break;
 793         }
 794         of_node_put(prev);
 795         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 796         return next;
 797 }
 798 EXPORT_SYMBOL(of_get_next_available_child);
 799 
 800 /**
 801  *      of_get_next_cpu_node - Iterate on cpu nodes
 802  *      @prev:  previous child of the /cpus node, or NULL to get first
 803  *
 804  *      Returns a cpu node pointer with refcount incremented, use of_node_put()
 805  *      on it when done. Returns NULL when prev is the last child. Decrements
 806  *      the refcount of prev.
 807  */
 808 struct device_node *of_get_next_cpu_node(struct device_node *prev)
 809 {
 810         struct device_node *next = NULL;
 811         unsigned long flags;
 812         struct device_node *node;
 813 
 814         if (!prev)
 815                 node = of_find_node_by_path("/cpus");
 816 
 817         raw_spin_lock_irqsave(&devtree_lock, flags);
 818         if (prev)
 819                 next = prev->sibling;
 820         else if (node) {
 821                 next = node->child;
 822                 of_node_put(node);
 823         }
 824         for (; next; next = next->sibling) {
 825                 if (!(of_node_name_eq(next, "cpu") ||
 826                       __of_node_is_type(next, "cpu")))
 827                         continue;
 828                 if (of_node_get(next))
 829                         break;
 830         }
 831         of_node_put(prev);
 832         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 833         return next;
 834 }
 835 EXPORT_SYMBOL(of_get_next_cpu_node);
 836 
 837 /**
 838  * of_get_compatible_child - Find compatible child node
 839  * @parent:     parent node
 840  * @compatible: compatible string
 841  *
 842  * Lookup child node whose compatible property contains the given compatible
 843  * string.
 844  *
 845  * Returns a node pointer with refcount incremented, use of_node_put() on it
 846  * when done; or NULL if not found.
 847  */
 848 struct device_node *of_get_compatible_child(const struct device_node *parent,
 849                                 const char *compatible)
 850 {
 851         struct device_node *child;
 852 
 853         for_each_child_of_node(parent, child) {
 854                 if (of_device_is_compatible(child, compatible))
 855                         break;
 856         }
 857 
 858         return child;
 859 }
 860 EXPORT_SYMBOL(of_get_compatible_child);
 861 
 862 /**
 863  *      of_get_child_by_name - Find the child node by name for a given parent
 864  *      @node:  parent node
 865  *      @name:  child name to look for.
 866  *
 867  *      This function looks for child node for given matching name
 868  *
 869  *      Returns a node pointer if found, with refcount incremented, use
 870  *      of_node_put() on it when done.
 871  *      Returns NULL if node is not found.
 872  */
 873 struct device_node *of_get_child_by_name(const struct device_node *node,
 874                                 const char *name)
 875 {
 876         struct device_node *child;
 877 
 878         for_each_child_of_node(node, child)
 879                 if (of_node_name_eq(child, name))
 880                         break;
 881         return child;
 882 }
 883 EXPORT_SYMBOL(of_get_child_by_name);
 884 
 885 struct device_node *__of_find_node_by_path(struct device_node *parent,
 886                                                 const char *path)
 887 {
 888         struct device_node *child;
 889         int len;
 890 
 891         len = strcspn(path, "/:");
 892         if (!len)
 893                 return NULL;
 894 
 895         __for_each_child_of_node(parent, child) {
 896                 const char *name = kbasename(child->full_name);
 897                 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
 898                         return child;
 899         }
 900         return NULL;
 901 }
 902 
 903 struct device_node *__of_find_node_by_full_path(struct device_node *node,
 904                                                 const char *path)
 905 {
 906         const char *separator = strchr(path, ':');
 907 
 908         while (node && *path == '/') {
 909                 struct device_node *tmp = node;
 910 
 911                 path++; /* Increment past '/' delimiter */
 912                 node = __of_find_node_by_path(node, path);
 913                 of_node_put(tmp);
 914                 path = strchrnul(path, '/');
 915                 if (separator && separator < path)
 916                         break;
 917         }
 918         return node;
 919 }
 920 
 921 /**
 922  *      of_find_node_opts_by_path - Find a node matching a full OF path
 923  *      @path: Either the full path to match, or if the path does not
 924  *             start with '/', the name of a property of the /aliases
 925  *             node (an alias).  In the case of an alias, the node
 926  *             matching the alias' value will be returned.
 927  *      @opts: Address of a pointer into which to store the start of
 928  *             an options string appended to the end of the path with
 929  *             a ':' separator.
 930  *
 931  *      Valid paths:
 932  *              /foo/bar        Full path
 933  *              foo             Valid alias
 934  *              foo/bar         Valid alias + relative path
 935  *
 936  *      Returns a node pointer with refcount incremented, use
 937  *      of_node_put() on it when done.
 938  */
 939 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
 940 {
 941         struct device_node *np = NULL;
 942         struct property *pp;
 943         unsigned long flags;
 944         const char *separator = strchr(path, ':');
 945 
 946         if (opts)
 947                 *opts = separator ? separator + 1 : NULL;
 948 
 949         if (strcmp(path, "/") == 0)
 950                 return of_node_get(of_root);
 951 
 952         /* The path could begin with an alias */
 953         if (*path != '/') {
 954                 int len;
 955                 const char *p = separator;
 956 
 957                 if (!p)
 958                         p = strchrnul(path, '/');
 959                 len = p - path;
 960 
 961                 /* of_aliases must not be NULL */
 962                 if (!of_aliases)
 963                         return NULL;
 964 
 965                 for_each_property_of_node(of_aliases, pp) {
 966                         if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
 967                                 np = of_find_node_by_path(pp->value);
 968                                 break;
 969                         }
 970                 }
 971                 if (!np)
 972                         return NULL;
 973                 path = p;
 974         }
 975 
 976         /* Step down the tree matching path components */
 977         raw_spin_lock_irqsave(&devtree_lock, flags);
 978         if (!np)
 979                 np = of_node_get(of_root);
 980         np = __of_find_node_by_full_path(np, path);
 981         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 982         return np;
 983 }
 984 EXPORT_SYMBOL(of_find_node_opts_by_path);
 985 
 986 /**
 987  *      of_find_node_by_name - Find a node by its "name" property
 988  *      @from:  The node to start searching from or NULL; the node
 989  *              you pass will not be searched, only the next one
 990  *              will. Typically, you pass what the previous call
 991  *              returned. of_node_put() will be called on @from.
 992  *      @name:  The name string to match against
 993  *
 994  *      Returns a node pointer with refcount incremented, use
 995  *      of_node_put() on it when done.
 996  */
 997 struct device_node *of_find_node_by_name(struct device_node *from,
 998         const char *name)
 999 {
1000         struct device_node *np;
1001         unsigned long flags;
1002 
1003         raw_spin_lock_irqsave(&devtree_lock, flags);
1004         for_each_of_allnodes_from(from, np)
1005                 if (of_node_name_eq(np, name) && of_node_get(np))
1006                         break;
1007         of_node_put(from);
1008         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1009         return np;
1010 }
1011 EXPORT_SYMBOL(of_find_node_by_name);
1012 
1013 /**
1014  *      of_find_node_by_type - Find a node by its "device_type" property
1015  *      @from:  The node to start searching from, or NULL to start searching
1016  *              the entire device tree. The node you pass will not be
1017  *              searched, only the next one will; typically, you pass
1018  *              what the previous call returned. of_node_put() will be
1019  *              called on from for you.
1020  *      @type:  The type string to match against
1021  *
1022  *      Returns a node pointer with refcount incremented, use
1023  *      of_node_put() on it when done.
1024  */
1025 struct device_node *of_find_node_by_type(struct device_node *from,
1026         const char *type)
1027 {
1028         struct device_node *np;
1029         unsigned long flags;
1030 
1031         raw_spin_lock_irqsave(&devtree_lock, flags);
1032         for_each_of_allnodes_from(from, np)
1033                 if (__of_node_is_type(np, type) && of_node_get(np))
1034                         break;
1035         of_node_put(from);
1036         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1037         return np;
1038 }
1039 EXPORT_SYMBOL(of_find_node_by_type);
1040 
1041 /**
1042  *      of_find_compatible_node - Find a node based on type and one of the
1043  *                                tokens in its "compatible" property
1044  *      @from:          The node to start searching from or NULL, the node
1045  *                      you pass will not be searched, only the next one
1046  *                      will; typically, you pass what the previous call
1047  *                      returned. of_node_put() will be called on it
1048  *      @type:          The type string to match "device_type" or NULL to ignore
1049  *      @compatible:    The string to match to one of the tokens in the device
1050  *                      "compatible" list.
1051  *
1052  *      Returns a node pointer with refcount incremented, use
1053  *      of_node_put() on it when done.
1054  */
1055 struct device_node *of_find_compatible_node(struct device_node *from,
1056         const char *type, const char *compatible)
1057 {
1058         struct device_node *np;
1059         unsigned long flags;
1060 
1061         raw_spin_lock_irqsave(&devtree_lock, flags);
1062         for_each_of_allnodes_from(from, np)
1063                 if (__of_device_is_compatible(np, compatible, type, NULL) &&
1064                     of_node_get(np))
1065                         break;
1066         of_node_put(from);
1067         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1068         return np;
1069 }
1070 EXPORT_SYMBOL(of_find_compatible_node);
1071 
1072 /**
1073  *      of_find_node_with_property - Find a node which has a property with
1074  *                                   the given name.
1075  *      @from:          The node to start searching from or NULL, the node
1076  *                      you pass will not be searched, only the next one
1077  *                      will; typically, you pass what the previous call
1078  *                      returned. of_node_put() will be called on it
1079  *      @prop_name:     The name of the property to look for.
1080  *
1081  *      Returns a node pointer with refcount incremented, use
1082  *      of_node_put() on it when done.
1083  */
1084 struct device_node *of_find_node_with_property(struct device_node *from,
1085         const char *prop_name)
1086 {
1087         struct device_node *np;
1088         struct property *pp;
1089         unsigned long flags;
1090 
1091         raw_spin_lock_irqsave(&devtree_lock, flags);
1092         for_each_of_allnodes_from(from, np) {
1093                 for (pp = np->properties; pp; pp = pp->next) {
1094                         if (of_prop_cmp(pp->name, prop_name) == 0) {
1095                                 of_node_get(np);
1096                                 goto out;
1097                         }
1098                 }
1099         }
1100 out:
1101         of_node_put(from);
1102         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1103         return np;
1104 }
1105 EXPORT_SYMBOL(of_find_node_with_property);
1106 
1107 static
1108 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
1109                                            const struct device_node *node)
1110 {
1111         const struct of_device_id *best_match = NULL;
1112         int score, best_score = 0;
1113 
1114         if (!matches)
1115                 return NULL;
1116 
1117         for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
1118                 score = __of_device_is_compatible(node, matches->compatible,
1119                                                   matches->type, matches->name);
1120                 if (score > best_score) {
1121                         best_match = matches;
1122                         best_score = score;
1123                 }
1124         }
1125 
1126         return best_match;
1127 }
1128 
1129 /**
1130  * of_match_node - Tell if a device_node has a matching of_match structure
1131  *      @matches:       array of of device match structures to search in
1132  *      @node:          the of device structure to match against
1133  *
1134  *      Low level utility function used by device matching.
1135  */
1136 const struct of_device_id *of_match_node(const struct of_device_id *matches,
1137                                          const struct device_node *node)
1138 {
1139         const struct of_device_id *match;
1140         unsigned long flags;
1141 
1142         raw_spin_lock_irqsave(&devtree_lock, flags);
1143         match = __of_match_node(matches, node);
1144         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1145         return match;
1146 }
1147 EXPORT_SYMBOL(of_match_node);
1148 
1149 /**
1150  *      of_find_matching_node_and_match - Find a node based on an of_device_id
1151  *                                        match table.
1152  *      @from:          The node to start searching from or NULL, the node
1153  *                      you pass will not be searched, only the next one
1154  *                      will; typically, you pass what the previous call
1155  *                      returned. of_node_put() will be called on it
1156  *      @matches:       array of of device match structures to search in
1157  *      @match          Updated to point at the matches entry which matched
1158  *
1159  *      Returns a node pointer with refcount incremented, use
1160  *      of_node_put() on it when done.
1161  */
1162 struct device_node *of_find_matching_node_and_match(struct device_node *from,
1163                                         const struct of_device_id *matches,
1164                                         const struct of_device_id **match)
1165 {
1166         struct device_node *np;
1167         const struct of_device_id *m;
1168         unsigned long flags;
1169 
1170         if (match)
1171                 *match = NULL;
1172 
1173         raw_spin_lock_irqsave(&devtree_lock, flags);
1174         for_each_of_allnodes_from(from, np) {
1175                 m = __of_match_node(matches, np);
1176                 if (m && of_node_get(np)) {
1177                         if (match)
1178                                 *match = m;
1179                         break;
1180                 }
1181         }
1182         of_node_put(from);
1183         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1184         return np;
1185 }
1186 EXPORT_SYMBOL(of_find_matching_node_and_match);
1187 
1188 /**
1189  * of_modalias_node - Lookup appropriate modalias for a device node
1190  * @node:       pointer to a device tree node
1191  * @modalias:   Pointer to buffer that modalias value will be copied into
1192  * @len:        Length of modalias value
1193  *
1194  * Based on the value of the compatible property, this routine will attempt
1195  * to choose an appropriate modalias value for a particular device tree node.
1196  * It does this by stripping the manufacturer prefix (as delimited by a ',')
1197  * from the first entry in the compatible list property.
1198  *
1199  * This routine returns 0 on success, <0 on failure.
1200  */
1201 int of_modalias_node(struct device_node *node, char *modalias, int len)
1202 {
1203         const char *compatible, *p;
1204         int cplen;
1205 
1206         compatible = of_get_property(node, "compatible", &cplen);
1207         if (!compatible || strlen(compatible) > cplen)
1208                 return -ENODEV;
1209         p = strchr(compatible, ',');
1210         strlcpy(modalias, p ? p + 1 : compatible, len);
1211         return 0;
1212 }
1213 EXPORT_SYMBOL_GPL(of_modalias_node);
1214 
1215 /**
1216  * of_find_node_by_phandle - Find a node given a phandle
1217  * @handle:     phandle of the node to find
1218  *
1219  * Returns a node pointer with refcount incremented, use
1220  * of_node_put() on it when done.
1221  */
1222 struct device_node *of_find_node_by_phandle(phandle handle)
1223 {
1224         struct device_node *np = NULL;
1225         unsigned long flags;
1226         phandle masked_handle;
1227 
1228         if (!handle)
1229                 return NULL;
1230 
1231         raw_spin_lock_irqsave(&devtree_lock, flags);
1232 
1233         masked_handle = handle & phandle_cache_mask;
1234 
1235         if (phandle_cache) {
1236                 if (phandle_cache[masked_handle] &&
1237                     handle == phandle_cache[masked_handle]->phandle)
1238                         np = phandle_cache[masked_handle];
1239                 if (np && of_node_check_flag(np, OF_DETACHED)) {
1240                         WARN_ON(1); /* did not uncache np on node removal */
1241                         of_node_put(np);
1242                         phandle_cache[masked_handle] = NULL;
1243                         np = NULL;
1244                 }
1245         }
1246 
1247         if (!np) {
1248                 for_each_of_allnodes(np)
1249                         if (np->phandle == handle &&
1250                             !of_node_check_flag(np, OF_DETACHED)) {
1251                                 if (phandle_cache) {
1252                                         /* will put when removed from cache */
1253                                         of_node_get(np);
1254                                         phandle_cache[masked_handle] = np;
1255                                 }
1256                                 break;
1257                         }
1258         }
1259 
1260         of_node_get(np);
1261         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1262         return np;
1263 }
1264 EXPORT_SYMBOL(of_find_node_by_phandle);
1265 
1266 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1267 {
1268         int i;
1269         printk("%s %pOF", msg, args->np);
1270         for (i = 0; i < args->args_count; i++) {
1271                 const char delim = i ? ',' : ':';
1272 
1273                 pr_cont("%c%08x", delim, args->args[i]);
1274         }
1275         pr_cont("\n");
1276 }
1277 
1278 int of_phandle_iterator_init(struct of_phandle_iterator *it,
1279                 const struct device_node *np,
1280                 const char *list_name,
1281                 const char *cells_name,
1282                 int cell_count)
1283 {
1284         const __be32 *list;
1285         int size;
1286 
1287         memset(it, 0, sizeof(*it));
1288 
1289         /*
1290          * one of cell_count or cells_name must be provided to determine the
1291          * argument length.
1292          */
1293         if (cell_count < 0 && !cells_name)
1294                 return -EINVAL;
1295 
1296         list = of_get_property(np, list_name, &size);
1297         if (!list)
1298                 return -ENOENT;
1299 
1300         it->cells_name = cells_name;
1301         it->cell_count = cell_count;
1302         it->parent = np;
1303         it->list_end = list + size / sizeof(*list);
1304         it->phandle_end = list;
1305         it->cur = list;
1306 
1307         return 0;
1308 }
1309 EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
1310 
1311 int of_phandle_iterator_next(struct of_phandle_iterator *it)
1312 {
1313         uint32_t count = 0;
1314 
1315         if (it->node) {
1316                 of_node_put(it->node);
1317                 it->node = NULL;
1318         }
1319 
1320         if (!it->cur || it->phandle_end >= it->list_end)
1321                 return -ENOENT;
1322 
1323         it->cur = it->phandle_end;
1324 
1325         /* If phandle is 0, then it is an empty entry with no arguments. */
1326         it->phandle = be32_to_cpup(it->cur++);
1327 
1328         if (it->phandle) {
1329 
1330                 /*
1331                  * Find the provider node and parse the #*-cells property to
1332                  * determine the argument length.
1333                  */
1334                 it->node = of_find_node_by_phandle(it->phandle);
1335 
1336                 if (it->cells_name) {
1337                         if (!it->node) {
1338                                 pr_err("%pOF: could not find phandle\n",
1339                                        it->parent);
1340                                 goto err;
1341                         }
1342 
1343                         if (of_property_read_u32(it->node, it->cells_name,
1344                                                  &count)) {
1345                                 /*
1346                                  * If both cell_count and cells_name is given,
1347                                  * fall back to cell_count in absence
1348                                  * of the cells_name property
1349                                  */
1350                                 if (it->cell_count >= 0) {
1351                                         count = it->cell_count;
1352                                 } else {
1353                                         pr_err("%pOF: could not get %s for %pOF\n",
1354                                                it->parent,
1355                                                it->cells_name,
1356                                                it->node);
1357                                         goto err;
1358                                 }
1359                         }
1360                 } else {
1361                         count = it->cell_count;
1362                 }
1363 
1364                 /*
1365                  * Make sure that the arguments actually fit in the remaining
1366                  * property data length
1367                  */
1368                 if (it->cur + count > it->list_end) {
1369                         pr_err("%pOF: %s = %d found %d\n",
1370                                it->parent, it->cells_name,
1371                                count, it->cell_count);
1372                         goto err;
1373                 }
1374         }
1375 
1376         it->phandle_end = it->cur + count;
1377         it->cur_count = count;
1378 
1379         return 0;
1380 
1381 err:
1382         if (it->node) {
1383                 of_node_put(it->node);
1384                 it->node = NULL;
1385         }
1386 
1387         return -EINVAL;
1388 }
1389 EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
1390 
1391 int of_phandle_iterator_args(struct of_phandle_iterator *it,
1392                              uint32_t *args,
1393                              int size)
1394 {
1395         int i, count;
1396 
1397         count = it->cur_count;
1398 
1399         if (WARN_ON(size < count))
1400                 count = size;
1401 
1402         for (i = 0; i < count; i++)
1403                 args[i] = be32_to_cpup(it->cur++);
1404 
1405         return count;
1406 }
1407 
1408 static int __of_parse_phandle_with_args(const struct device_node *np,
1409                                         const char *list_name,
1410                                         const char *cells_name,
1411                                         int cell_count, int index,
1412                                         struct of_phandle_args *out_args)
1413 {
1414         struct of_phandle_iterator it;
1415         int rc, cur_index = 0;
1416 
1417         /* Loop over the phandles until all the requested entry is found */
1418         of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1419                 /*
1420                  * All of the error cases bail out of the loop, so at
1421                  * this point, the parsing is successful. If the requested
1422                  * index matches, then fill the out_args structure and return,
1423                  * or return -ENOENT for an empty entry.
1424                  */
1425                 rc = -ENOENT;
1426                 if (cur_index == index) {
1427                         if (!it.phandle)
1428                                 goto err;
1429 
1430                         if (out_args) {
1431                                 int c;
1432 
1433                                 c = of_phandle_iterator_args(&it,
1434                                                              out_args->args,
1435                                                              MAX_PHANDLE_ARGS);
1436                                 out_args->np = it.node;
1437                                 out_args->args_count = c;
1438                         } else {
1439                                 of_node_put(it.node);
1440                         }
1441 
1442                         /* Found it! return success */
1443                         return 0;
1444                 }
1445 
1446                 cur_index++;
1447         }
1448 
1449         /*
1450          * Unlock node before returning result; will be one of:
1451          * -ENOENT : index is for empty phandle
1452          * -EINVAL : parsing error on data
1453          */
1454 
1455  err:
1456         of_node_put(it.node);
1457         return rc;
1458 }
1459 
1460 /**
1461  * of_parse_phandle - Resolve a phandle property to a device_node pointer
1462  * @np: Pointer to device node holding phandle property
1463  * @phandle_name: Name of property holding a phandle value
1464  * @index: For properties holding a table of phandles, this is the index into
1465  *         the table
1466  *
1467  * Returns the device_node pointer with refcount incremented.  Use
1468  * of_node_put() on it when done.
1469  */
1470 struct device_node *of_parse_phandle(const struct device_node *np,
1471                                      const char *phandle_name, int index)
1472 {
1473         struct of_phandle_args args;
1474 
1475         if (index < 0)
1476                 return NULL;
1477 
1478         if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1479                                          index, &args))
1480                 return NULL;
1481 
1482         return args.np;
1483 }
1484 EXPORT_SYMBOL(of_parse_phandle);
1485 
1486 /**
1487  * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1488  * @np:         pointer to a device tree node containing a list
1489  * @list_name:  property name that contains a list
1490  * @cells_name: property name that specifies phandles' arguments count
1491  * @index:      index of a phandle to parse out
1492  * @out_args:   optional pointer to output arguments structure (will be filled)
1493  *
1494  * This function is useful to parse lists of phandles and their arguments.
1495  * Returns 0 on success and fills out_args, on error returns appropriate
1496  * errno value.
1497  *
1498  * Caller is responsible to call of_node_put() on the returned out_args->np
1499  * pointer.
1500  *
1501  * Example:
1502  *
1503  * phandle1: node1 {
1504  *      #list-cells = <2>;
1505  * }
1506  *
1507  * phandle2: node2 {
1508  *      #list-cells = <1>;
1509  * }
1510  *
1511  * node3 {
1512  *      list = <&phandle1 1 2 &phandle2 3>;
1513  * }
1514  *
1515  * To get a device_node of the `node2' node you may call this:
1516  * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1517  */
1518 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1519                                 const char *cells_name, int index,
1520                                 struct of_phandle_args *out_args)
1521 {
1522         int cell_count = -1;
1523 
1524         if (index < 0)
1525                 return -EINVAL;
1526 
1527         /* If cells_name is NULL we assume a cell count of 0 */
1528         if (!cells_name)
1529                 cell_count = 0;
1530 
1531         return __of_parse_phandle_with_args(np, list_name, cells_name,
1532                                             cell_count, index, out_args);
1533 }
1534 EXPORT_SYMBOL(of_parse_phandle_with_args);
1535 
1536 /**
1537  * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
1538  * @np:         pointer to a device tree node containing a list
1539  * @list_name:  property name that contains a list
1540  * @stem_name:  stem of property names that specify phandles' arguments count
1541  * @index:      index of a phandle to parse out
1542  * @out_args:   optional pointer to output arguments structure (will be filled)
1543  *
1544  * This function is useful to parse lists of phandles and their arguments.
1545  * Returns 0 on success and fills out_args, on error returns appropriate errno
1546  * value. The difference between this function and of_parse_phandle_with_args()
1547  * is that this API remaps a phandle if the node the phandle points to has
1548  * a <@stem_name>-map property.
1549  *
1550  * Caller is responsible to call of_node_put() on the returned out_args->np
1551  * pointer.
1552  *
1553  * Example:
1554  *
1555  * phandle1: node1 {
1556  *      #list-cells = <2>;
1557  * }
1558  *
1559  * phandle2: node2 {
1560  *      #list-cells = <1>;
1561  * }
1562  *
1563  * phandle3: node3 {
1564  *      #list-cells = <1>;
1565  *      list-map = <0 &phandle2 3>,
1566  *                 <1 &phandle2 2>,
1567  *                 <2 &phandle1 5 1>;
1568  *      list-map-mask = <0x3>;
1569  * };
1570  *
1571  * node4 {
1572  *      list = <&phandle1 1 2 &phandle3 0>;
1573  * }
1574  *
1575  * To get a device_node of the `node2' node you may call this:
1576  * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
1577  */
1578 int of_parse_phandle_with_args_map(const struct device_node *np,
1579                                    const char *list_name,
1580                                    const char *stem_name,
1581                                    int index, struct of_phandle_args *out_args)
1582 {
1583         char *cells_name, *map_name = NULL, *mask_name = NULL;
1584         char *pass_name = NULL;
1585         struct device_node *cur, *new = NULL;
1586         const __be32 *map, *mask, *pass;
1587         static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
1588         static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
1589         __be32 initial_match_array[MAX_PHANDLE_ARGS];
1590         const __be32 *match_array = initial_match_array;
1591         int i, ret, map_len, match;
1592         u32 list_size, new_size;
1593 
1594         if (index < 0)
1595                 return -EINVAL;
1596 
1597         cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
1598         if (!cells_name)
1599                 return -ENOMEM;
1600 
1601         ret = -ENOMEM;
1602         map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
1603         if (!map_name)
1604                 goto free;
1605 
1606         mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
1607         if (!mask_name)
1608                 goto free;
1609 
1610         pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
1611         if (!pass_name)
1612                 goto free;
1613 
1614         ret = __of_parse_phandle_with_args(np, list_name, cells_name, -1, index,
1615                                            out_args);
1616         if (ret)
1617                 goto free;
1618 
1619         /* Get the #<list>-cells property */
1620         cur = out_args->np;
1621         ret = of_property_read_u32(cur, cells_name, &list_size);
1622         if (ret < 0)
1623                 goto put;
1624 
1625         /* Precalculate the match array - this simplifies match loop */
1626         for (i = 0; i < list_size; i++)
1627                 initial_match_array[i] = cpu_to_be32(out_args->args[i]);
1628 
1629         ret = -EINVAL;
1630         while (cur) {
1631                 /* Get the <list>-map property */
1632                 map = of_get_property(cur, map_name, &map_len);
1633                 if (!map) {
1634                         ret = 0;
1635                         goto free;
1636                 }
1637                 map_len /= sizeof(u32);
1638 
1639                 /* Get the <list>-map-mask property (optional) */
1640                 mask = of_get_property(cur, mask_name, NULL);
1641                 if (!mask)
1642                         mask = dummy_mask;
1643                 /* Iterate through <list>-map property */
1644                 match = 0;
1645                 while (map_len > (list_size + 1) && !match) {
1646                         /* Compare specifiers */
1647                         match = 1;
1648                         for (i = 0; i < list_size; i++, map_len--)
1649                                 match &= !((match_array[i] ^ *map++) & mask[i]);
1650 
1651                         of_node_put(new);
1652                         new = of_find_node_by_phandle(be32_to_cpup(map));
1653                         map++;
1654                         map_len--;
1655 
1656                         /* Check if not found */
1657                         if (!new)
1658                                 goto put;
1659 
1660                         if (!of_device_is_available(new))
1661                                 match = 0;
1662 
1663                         ret = of_property_read_u32(new, cells_name, &new_size);
1664                         if (ret)
1665                                 goto put;
1666 
1667                         /* Check for malformed properties */
1668                         if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
1669                                 goto put;
1670                         if (map_len < new_size)
1671                                 goto put;
1672 
1673                         /* Move forward by new node's #<list>-cells amount */
1674                         map += new_size;
1675                         map_len -= new_size;
1676                 }
1677                 if (!match)
1678                         goto put;
1679 
1680                 /* Get the <list>-map-pass-thru property (optional) */
1681                 pass = of_get_property(cur, pass_name, NULL);
1682                 if (!pass)
1683                         pass = dummy_pass;
1684 
1685                 /*
1686                  * Successfully parsed a <list>-map translation; copy new
1687                  * specifier into the out_args structure, keeping the
1688                  * bits specified in <list>-map-pass-thru.
1689                  */
1690                 match_array = map - new_size;
1691                 for (i = 0; i < new_size; i++) {
1692                         __be32 val = *(map - new_size + i);
1693 
1694                         if (i < list_size) {
1695                                 val &= ~pass[i];
1696                                 val |= cpu_to_be32(out_args->args[i]) & pass[i];
1697                         }
1698 
1699                         out_args->args[i] = be32_to_cpu(val);
1700                 }
1701                 out_args->args_count = list_size = new_size;
1702                 /* Iterate again with new provider */
1703                 out_args->np = new;
1704                 of_node_put(cur);
1705                 cur = new;
1706         }
1707 put:
1708         of_node_put(cur);
1709         of_node_put(new);
1710 free:
1711         kfree(mask_name);
1712         kfree(map_name);
1713         kfree(cells_name);
1714         kfree(pass_name);
1715 
1716         return ret;
1717 }
1718 EXPORT_SYMBOL(of_parse_phandle_with_args_map);
1719 
1720 /**
1721  * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1722  * @np:         pointer to a device tree node containing a list
1723  * @list_name:  property name that contains a list
1724  * @cell_count: number of argument cells following the phandle
1725  * @index:      index of a phandle to parse out
1726  * @out_args:   optional pointer to output arguments structure (will be filled)
1727  *
1728  * This function is useful to parse lists of phandles and their arguments.
1729  * Returns 0 on success and fills out_args, on error returns appropriate
1730  * errno value.
1731  *
1732  * Caller is responsible to call of_node_put() on the returned out_args->np
1733  * pointer.
1734  *
1735  * Example:
1736  *
1737  * phandle1: node1 {
1738  * }
1739  *
1740  * phandle2: node2 {
1741  * }
1742  *
1743  * node3 {
1744  *      list = <&phandle1 0 2 &phandle2 2 3>;
1745  * }
1746  *
1747  * To get a device_node of the `node2' node you may call this:
1748  * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1749  */
1750 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1751                                 const char *list_name, int cell_count,
1752                                 int index, struct of_phandle_args *out_args)
1753 {
1754         if (index < 0)
1755                 return -EINVAL;
1756         return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1757                                            index, out_args);
1758 }
1759 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1760 
1761 /**
1762  * of_count_phandle_with_args() - Find the number of phandles references in a property
1763  * @np:         pointer to a device tree node containing a list
1764  * @list_name:  property name that contains a list
1765  * @cells_name: property name that specifies phandles' arguments count
1766  *
1767  * Returns the number of phandle + argument tuples within a property. It
1768  * is a typical pattern to encode a list of phandle and variable
1769  * arguments into a single property. The number of arguments is encoded
1770  * by a property in the phandle-target node. For example, a gpios
1771  * property would contain a list of GPIO specifies consisting of a
1772  * phandle and 1 or more arguments. The number of arguments are
1773  * determined by the #gpio-cells property in the node pointed to by the
1774  * phandle.
1775  */
1776 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1777                                 const char *cells_name)
1778 {
1779         struct of_phandle_iterator it;
1780         int rc, cur_index = 0;
1781 
1782         /*
1783          * If cells_name is NULL we assume a cell count of 0. This makes
1784          * counting the phandles trivial as each 32bit word in the list is a
1785          * phandle and no arguments are to consider. So we don't iterate through
1786          * the list but just use the length to determine the phandle count.
1787          */
1788         if (!cells_name) {
1789                 const __be32 *list;
1790                 int size;
1791 
1792                 list = of_get_property(np, list_name, &size);
1793                 if (!list)
1794                         return -ENOENT;
1795 
1796                 return size / sizeof(*list);
1797         }
1798 
1799         rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
1800         if (rc)
1801                 return rc;
1802 
1803         while ((rc = of_phandle_iterator_next(&it)) == 0)
1804                 cur_index += 1;
1805 
1806         if (rc != -ENOENT)
1807                 return rc;
1808 
1809         return cur_index;
1810 }
1811 EXPORT_SYMBOL(of_count_phandle_with_args);
1812 
1813 /**
1814  * __of_add_property - Add a property to a node without lock operations
1815  */
1816 int __of_add_property(struct device_node *np, struct property *prop)
1817 {
1818         struct property **next;
1819 
1820         prop->next = NULL;
1821         next = &np->properties;
1822         while (*next) {
1823                 if (strcmp(prop->name, (*next)->name) == 0)
1824                         /* duplicate ! don't insert it */
1825                         return -EEXIST;
1826 
1827                 next = &(*next)->next;
1828         }
1829         *next = prop;
1830 
1831         return 0;
1832 }
1833 
1834 /**
1835  * of_add_property - Add a property to a node
1836  */
1837 int of_add_property(struct device_node *np, struct property *prop)
1838 {
1839         unsigned long flags;
1840         int rc;
1841 
1842         mutex_lock(&of_mutex);
1843 
1844         raw_spin_lock_irqsave(&devtree_lock, flags);
1845         rc = __of_add_property(np, prop);
1846         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1847 
1848         if (!rc)
1849                 __of_add_property_sysfs(np, prop);
1850 
1851         mutex_unlock(&of_mutex);
1852 
1853         if (!rc)
1854                 of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1855 
1856         return rc;
1857 }
1858 
1859 int __of_remove_property(struct device_node *np, struct property *prop)
1860 {
1861         struct property **next;
1862 
1863         for (next = &np->properties; *next; next = &(*next)->next) {
1864                 if (*next == prop)
1865                         break;
1866         }
1867         if (*next == NULL)
1868                 return -ENODEV;
1869 
1870         /* found the node */
1871         *next = prop->next;
1872         prop->next = np->deadprops;
1873         np->deadprops = prop;
1874 
1875         return 0;
1876 }
1877 
1878 /**
1879  * of_remove_property - Remove a property from a node.
1880  *
1881  * Note that we don't actually remove it, since we have given out
1882  * who-knows-how-many pointers to the data using get-property.
1883  * Instead we just move the property to the "dead properties"
1884  * list, so it won't be found any more.
1885  */
1886 int of_remove_property(struct device_node *np, struct property *prop)
1887 {
1888         unsigned long flags;
1889         int rc;
1890 
1891         if (!prop)
1892                 return -ENODEV;
1893 
1894         mutex_lock(&of_mutex);
1895 
1896         raw_spin_lock_irqsave(&devtree_lock, flags);
1897         rc = __of_remove_property(np, prop);
1898         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1899 
1900         if (!rc)
1901                 __of_remove_property_sysfs(np, prop);
1902 
1903         mutex_unlock(&of_mutex);
1904 
1905         if (!rc)
1906                 of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1907 
1908         return rc;
1909 }
1910 
1911 int __of_update_property(struct device_node *np, struct property *newprop,
1912                 struct property **oldpropp)
1913 {
1914         struct property **next, *oldprop;
1915 
1916         for (next = &np->properties; *next; next = &(*next)->next) {
1917                 if (of_prop_cmp((*next)->name, newprop->name) == 0)
1918                         break;
1919         }
1920         *oldpropp = oldprop = *next;
1921 
1922         if (oldprop) {
1923                 /* replace the node */
1924                 newprop->next = oldprop->next;
1925                 *next = newprop;
1926                 oldprop->next = np->deadprops;
1927                 np->deadprops = oldprop;
1928         } else {
1929                 /* new node */
1930                 newprop->next = NULL;
1931                 *next = newprop;
1932         }
1933 
1934         return 0;
1935 }
1936 
1937 /*
1938  * of_update_property - Update a property in a node, if the property does
1939  * not exist, add it.
1940  *
1941  * Note that we don't actually remove it, since we have given out
1942  * who-knows-how-many pointers to the data using get-property.
1943  * Instead we just move the property to the "dead properties" list,
1944  * and add the new property to the property list
1945  */
1946 int of_update_property(struct device_node *np, struct property *newprop)
1947 {
1948         struct property *oldprop;
1949         unsigned long flags;
1950         int rc;
1951 
1952         if (!newprop->name)
1953                 return -EINVAL;
1954 
1955         mutex_lock(&of_mutex);
1956 
1957         raw_spin_lock_irqsave(&devtree_lock, flags);
1958         rc = __of_update_property(np, newprop, &oldprop);
1959         raw_spin_unlock_irqrestore(&devtree_lock, flags);
1960 
1961         if (!rc)
1962                 __of_update_property_sysfs(np, newprop, oldprop);
1963 
1964         mutex_unlock(&of_mutex);
1965 
1966         if (!rc)
1967                 of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1968 
1969         return rc;
1970 }
1971 
1972 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1973                          int id, const char *stem, int stem_len)
1974 {
1975         ap->np = np;
1976         ap->id = id;
1977         strncpy(ap->stem, stem, stem_len);
1978         ap->stem[stem_len] = 0;
1979         list_add_tail(&ap->link, &aliases_lookup);
1980         pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
1981                  ap->alias, ap->stem, ap->id, np);
1982 }
1983 
1984 /**
1985  * of_alias_scan - Scan all properties of the 'aliases' node
1986  *
1987  * The function scans all the properties of the 'aliases' node and populates
1988  * the global lookup table with the properties.  It returns the
1989  * number of alias properties found, or an error code in case of failure.
1990  *
1991  * @dt_alloc:   An allocator that provides a virtual address to memory
1992  *              for storing the resulting tree
1993  */
1994 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1995 {
1996         struct property *pp;
1997 
1998         of_aliases = of_find_node_by_path("/aliases");
1999         of_chosen = of_find_node_by_path("/chosen");
2000         if (of_chosen == NULL)
2001                 of_chosen = of_find_node_by_path("/chosen@0");
2002 
2003         if (of_chosen) {
2004                 /* linux,stdout-path and /aliases/stdout are for legacy compatibility */
2005                 const char *name = NULL;
2006 
2007                 if (of_property_read_string(of_chosen, "stdout-path", &name))
2008                         of_property_read_string(of_chosen, "linux,stdout-path",
2009                                                 &name);
2010                 if (IS_ENABLED(CONFIG_PPC) && !name)
2011                         of_property_read_string(of_aliases, "stdout", &name);
2012                 if (name)
2013                         of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
2014         }
2015 
2016         if (!of_aliases)
2017                 return;
2018 
2019         for_each_property_of_node(of_aliases, pp) {
2020                 const char *start = pp->name;
2021                 const char *end = start + strlen(start);
2022                 struct device_node *np;
2023                 struct alias_prop *ap;
2024                 int id, len;
2025 
2026                 /* Skip those we do not want to proceed */
2027                 if (!strcmp(pp->name, "name") ||
2028                     !strcmp(pp->name, "phandle") ||
2029                     !strcmp(pp->name, "linux,phandle"))
2030                         continue;
2031 
2032                 np = of_find_node_by_path(pp->value);
2033                 if (!np)
2034                         continue;
2035 
2036                 /* walk the alias backwards to extract the id and work out
2037                  * the 'stem' string */
2038                 while (isdigit(*(end-1)) && end > start)
2039                         end--;
2040                 len = end - start;
2041 
2042                 if (kstrtoint(end, 10, &id) < 0)
2043                         continue;
2044 
2045                 /* Allocate an alias_prop with enough space for the stem */
2046                 ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
2047                 if (!ap)
2048                         continue;
2049                 memset(ap, 0, sizeof(*ap) + len + 1);
2050                 ap->alias = start;
2051                 of_alias_add(ap, np, id, start, len);
2052         }
2053 }
2054 
2055 /**
2056  * of_alias_get_id - Get alias id for the given device_node
2057  * @np:         Pointer to the given device_node
2058  * @stem:       Alias stem of the given device_node
2059  *
2060  * The function travels the lookup table to get the alias id for the given
2061  * device_node and alias stem.  It returns the alias id if found.
2062  */
2063 int of_alias_get_id(struct device_node *np, const char *stem)
2064 {
2065         struct alias_prop *app;
2066         int id = -ENODEV;
2067 
2068         mutex_lock(&of_mutex);
2069         list_for_each_entry(app, &aliases_lookup, link) {
2070                 if (strcmp(app->stem, stem) != 0)
2071                         continue;
2072 
2073                 if (np == app->np) {
2074                         id = app->id;
2075                         break;
2076                 }
2077         }
2078         mutex_unlock(&of_mutex);
2079 
2080         return id;
2081 }
2082 EXPORT_SYMBOL_GPL(of_alias_get_id);
2083 
2084 /**
2085  * of_alias_get_alias_list - Get alias list for the given device driver
2086  * @matches:    Array of OF device match structures to search in
2087  * @stem:       Alias stem of the given device_node
2088  * @bitmap:     Bitmap field pointer
2089  * @nbits:      Maximum number of alias IDs which can be recorded in bitmap
2090  *
2091  * The function travels the lookup table to record alias ids for the given
2092  * device match structures and alias stem.
2093  *
2094  * Return:      0 or -ENOSYS when !CONFIG_OF or
2095  *              -EOVERFLOW if alias ID is greater then allocated nbits
2096  */
2097 int of_alias_get_alias_list(const struct of_device_id *matches,
2098                              const char *stem, unsigned long *bitmap,
2099                              unsigned int nbits)
2100 {
2101         struct alias_prop *app;
2102         int ret = 0;
2103 
2104         /* Zero bitmap field to make sure that all the time it is clean */
2105         bitmap_zero(bitmap, nbits);
2106 
2107         mutex_lock(&of_mutex);
2108         pr_debug("%s: Looking for stem: %s\n", __func__, stem);
2109         list_for_each_entry(app, &aliases_lookup, link) {
2110                 pr_debug("%s: stem: %s, id: %d\n",
2111                          __func__, app->stem, app->id);
2112 
2113                 if (strcmp(app->stem, stem) != 0) {
2114                         pr_debug("%s: stem comparison didn't pass %s\n",
2115                                  __func__, app->stem);
2116                         continue;
2117                 }
2118 
2119                 if (of_match_node(matches, app->np)) {
2120                         pr_debug("%s: Allocated ID %d\n", __func__, app->id);
2121 
2122                         if (app->id >= nbits) {
2123                                 pr_warn("%s: ID %d >= than bitmap field %d\n",
2124                                         __func__, app->id, nbits);
2125                                 ret = -EOVERFLOW;
2126                         } else {
2127                                 set_bit(app->id, bitmap);
2128                         }
2129                 }
2130         }
2131         mutex_unlock(&of_mutex);
2132 
2133         return ret;
2134 }
2135 EXPORT_SYMBOL_GPL(of_alias_get_alias_list);
2136 
2137 /**
2138  * of_alias_get_highest_id - Get highest alias id for the given stem
2139  * @stem:       Alias stem to be examined
2140  *
2141  * The function travels the lookup table to get the highest alias id for the
2142  * given alias stem.  It returns the alias id if found.
2143  */
2144 int of_alias_get_highest_id(const char *stem)
2145 {
2146         struct alias_prop *app;
2147         int id = -ENODEV;
2148 
2149         mutex_lock(&of_mutex);
2150         list_for_each_entry(app, &aliases_lookup, link) {
2151                 if (strcmp(app->stem, stem) != 0)
2152                         continue;
2153 
2154                 if (app->id > id)
2155                         id = app->id;
2156         }
2157         mutex_unlock(&of_mutex);
2158 
2159         return id;
2160 }
2161 EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
2162 
2163 /**
2164  * of_console_check() - Test and setup console for DT setup
2165  * @dn - Pointer to device node
2166  * @name - Name to use for preferred console without index. ex. "ttyS"
2167  * @index - Index to use for preferred console.
2168  *
2169  * Check if the given device node matches the stdout-path property in the
2170  * /chosen node. If it does then register it as the preferred console and return
2171  * TRUE. Otherwise return FALSE.
2172  */
2173 bool of_console_check(struct device_node *dn, char *name, int index)
2174 {
2175         if (!dn || dn != of_stdout || console_set_on_cmdline)
2176                 return false;
2177 
2178         /*
2179          * XXX: cast `options' to char pointer to suppress complication
2180          * warnings: printk, UART and console drivers expect char pointer.
2181          */
2182         return !add_preferred_console(name, index, (char *)of_stdout_options);
2183 }
2184 EXPORT_SYMBOL_GPL(of_console_check);
2185 
2186 /**
2187  *      of_find_next_cache_node - Find a node's subsidiary cache
2188  *      @np:    node of type "cpu" or "cache"
2189  *
2190  *      Returns a node pointer with refcount incremented, use
2191  *      of_node_put() on it when done.  Caller should hold a reference
2192  *      to np.
2193  */
2194 struct device_node *of_find_next_cache_node(const struct device_node *np)
2195 {
2196         struct device_node *child, *cache_node;
2197 
2198         cache_node = of_parse_phandle(np, "l2-cache", 0);
2199         if (!cache_node)
2200                 cache_node = of_parse_phandle(np, "next-level-cache", 0);
2201 
2202         if (cache_node)
2203                 return cache_node;
2204 
2205         /* OF on pmac has nodes instead of properties named "l2-cache"
2206          * beneath CPU nodes.
2207          */
2208         if (IS_ENABLED(CONFIG_PPC_PMAC) && of_node_is_type(np, "cpu"))
2209                 for_each_child_of_node(np, child)
2210                         if (of_node_is_type(child, "cache"))
2211                                 return child;
2212 
2213         return NULL;
2214 }
2215 
2216 /**
2217  * of_find_last_cache_level - Find the level at which the last cache is
2218  *              present for the given logical cpu
2219  *
2220  * @cpu: cpu number(logical index) for which the last cache level is needed
2221  *
2222  * Returns the the level at which the last cache is present. It is exactly
2223  * same as  the total number of cache levels for the given logical cpu.
2224  */
2225 int of_find_last_cache_level(unsigned int cpu)
2226 {
2227         u32 cache_level = 0;
2228         struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
2229 
2230         while (np) {
2231                 prev = np;
2232                 of_node_put(np);
2233                 np = of_find_next_cache_node(np);
2234         }
2235 
2236         of_property_read_u32(prev, "cache-level", &cache_level);
2237 
2238         return cache_level;
2239 }
2240 
2241 /**
2242  * of_map_rid - Translate a requester ID through a downstream mapping.
2243  * @np: root complex device node.
2244  * @rid: device requester ID to map.
2245  * @map_name: property name of the map to use.
2246  * @map_mask_name: optional property name of the mask to use.
2247  * @target: optional pointer to a target device node.
2248  * @id_out: optional pointer to receive the translated ID.
2249  *
2250  * Given a device requester ID, look up the appropriate implementation-defined
2251  * platform ID and/or the target device which receives transactions on that
2252  * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
2253  * @id_out may be NULL if only the other is required. If @target points to
2254  * a non-NULL device node pointer, only entries targeting that node will be
2255  * matched; if it points to a NULL value, it will receive the device node of
2256  * the first matching target phandle, with a reference held.
2257  *
2258  * Return: 0 on success or a standard error code on failure.
2259  */
2260 int of_map_rid(struct device_node *np, u32 rid,
2261                const char *map_name, const char *map_mask_name,
2262                struct device_node **target, u32 *id_out)
2263 {
2264         u32 map_mask, masked_rid;
2265         int map_len;
2266         const __be32 *map = NULL;
2267 
2268         if (!np || !map_name || (!target && !id_out))
2269                 return -EINVAL;
2270 
2271         map = of_get_property(np, map_name, &map_len);
2272         if (!map) {
2273                 if (target)
2274                         return -ENODEV;
2275                 /* Otherwise, no map implies no translation */
2276                 *id_out = rid;
2277                 return 0;
2278         }
2279 
2280         if (!map_len || map_len % (4 * sizeof(*map))) {
2281                 pr_err("%pOF: Error: Bad %s length: %d\n", np,
2282                         map_name, map_len);
2283                 return -EINVAL;
2284         }
2285 
2286         /* The default is to select all bits. */
2287         map_mask = 0xffffffff;
2288 
2289         /*
2290          * Can be overridden by "{iommu,msi}-map-mask" property.
2291          * If of_property_read_u32() fails, the default is used.
2292          */
2293         if (map_mask_name)
2294                 of_property_read_u32(np, map_mask_name, &map_mask);
2295 
2296         masked_rid = map_mask & rid;
2297         for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
2298                 struct device_node *phandle_node;
2299                 u32 rid_base = be32_to_cpup(map + 0);
2300                 u32 phandle = be32_to_cpup(map + 1);
2301                 u32 out_base = be32_to_cpup(map + 2);
2302                 u32 rid_len = be32_to_cpup(map + 3);
2303 
2304                 if (rid_base & ~map_mask) {
2305                         pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
2306                                 np, map_name, map_name,
2307                                 map_mask, rid_base);
2308                         return -EFAULT;
2309                 }
2310 
2311                 if (masked_rid < rid_base || masked_rid >= rid_base + rid_len)
2312                         continue;
2313 
2314                 phandle_node = of_find_node_by_phandle(phandle);
2315                 if (!phandle_node)
2316                         return -ENODEV;
2317 
2318                 if (target) {
2319                         if (*target)
2320                                 of_node_put(phandle_node);
2321                         else
2322                                 *target = phandle_node;
2323 
2324                         if (*target != phandle_node)
2325                                 continue;
2326                 }
2327 
2328                 if (id_out)
2329                         *id_out = masked_rid - rid_base + out_base;
2330 
2331                 pr_debug("%pOF: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
2332                         np, map_name, map_mask, rid_base, out_base,
2333                         rid_len, rid, masked_rid - rid_base + out_base);
2334                 return 0;
2335         }
2336 
2337         pr_info("%pOF: no %s translation for rid 0x%x on %pOF\n", np, map_name,
2338                 rid, target && *target ? *target : NULL);
2339 
2340         /* Bypasses translation */
2341         if (id_out)
2342                 *id_out = rid;
2343         return 0;
2344 }
2345 EXPORT_SYMBOL_GPL(of_map_rid);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/of/base.c

DEFINITIONS
