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
  34LIST_HEAD(aliases_lookup);
  35
  36struct device_node *of_root;
  37EXPORT_SYMBOL(of_root);
  38struct device_node *of_chosen;
  39EXPORT_SYMBOL(of_chosen);
  40struct device_node *of_aliases;
  41struct device_node *of_stdout;
  42static const char *of_stdout_options;
  43
  44struct kset *of_kset;
  45
  46/*
  47 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
  48 * This mutex must be held whenever modifications are being made to the
  49 * device tree. The of_{attach,detach}_node() and
  50 * of_{add,remove,update}_property() helpers make sure this happens.
  51 */
  52DEFINE_MUTEX(of_mutex);
  53
  54/* use when traversing tree through the child, sibling,
  55 * or parent members of struct device_node.
  56 */
  57DEFINE_RAW_SPINLOCK(devtree_lock);
  58
  59bool of_node_name_eq(const struct device_node *np, const char *name)
  60{
  61	const char *node_name;
  62	size_t len;
  63
  64	if (!np)
  65		return false;
  66
  67	node_name = kbasename(np->full_name);
  68	len = strchrnul(node_name, '@') - node_name;
  69
  70	return (strlen(name) == len) && (strncmp(node_name, name, len) == 0);
  71}
  72EXPORT_SYMBOL(of_node_name_eq);
  73
  74bool of_node_name_prefix(const struct device_node *np, const char *prefix)
  75{
  76	if (!np)
  77		return false;
  78
  79	return strncmp(kbasename(np->full_name), prefix, strlen(prefix)) == 0;
  80}
  81EXPORT_SYMBOL(of_node_name_prefix);
  82
  83static bool __of_node_is_type(const struct device_node *np, const char *type)
  84{
  85	const char *match = __of_get_property(np, "device_type", NULL);
  86
  87	return np && match && type && !strcmp(match, type);
  88}
  89
  90int of_bus_n_addr_cells(struct device_node *np)
  91{
  92	u32 cells;
  93
  94	for (; np; np = np->parent)
  95		if (!of_property_read_u32(np, "#address-cells", &cells))
  96			return cells;
  97
  98	/* No #address-cells property for the root node */
  99	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
 100}
 101
 102int of_n_addr_cells(struct device_node *np)
 103{
 104	if (np->parent)
 105		np = np->parent;
 106
 107	return of_bus_n_addr_cells(np);
 108}
 109EXPORT_SYMBOL(of_n_addr_cells);
 110
 111int of_bus_n_size_cells(struct device_node *np)
 112{
 113	u32 cells;
 114
 115	for (; np; np = np->parent)
 116		if (!of_property_read_u32(np, "#size-cells", &cells))
 117			return cells;
 118
 119	/* No #size-cells property for the root node */
 120	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
 121}
 122
 123int of_n_size_cells(struct device_node *np)
 124{
 125	if (np->parent)
 126		np = np->parent;
 127
 128	return of_bus_n_size_cells(np);
 129}
 130EXPORT_SYMBOL(of_n_size_cells);
 131
 132#ifdef CONFIG_NUMA
 133int __weak of_node_to_nid(struct device_node *np)
 134{
 135	return NUMA_NO_NODE;
 136}
 137#endif
 138
 139#define OF_PHANDLE_CACHE_BITS	7
 140#define OF_PHANDLE_CACHE_SZ	BIT(OF_PHANDLE_CACHE_BITS)
 141
 142static struct device_node *phandle_cache[OF_PHANDLE_CACHE_SZ];
 143
 144static u32 of_phandle_cache_hash(phandle handle)
 145{
 146	return hash_32(handle, OF_PHANDLE_CACHE_BITS);
 147}
 148
 149/*
 150 * Caller must hold devtree_lock.
 151 */
 152void __of_phandle_cache_inv_entry(phandle handle)
 153{
 154	u32 handle_hash;
 155	struct device_node *np;
 156
 157	if (!handle)
 158		return;
 159
 160	handle_hash = of_phandle_cache_hash(handle);
 161
 162	np = phandle_cache[handle_hash];
 163	if (np && handle == np->phandle)
 164		phandle_cache[handle_hash] = NULL;
 165}
 166
 167void __init of_core_init(void)
 168{
 169	struct device_node *np;
 170
 
 171
 172	/* Create the kset, and register existing nodes */
 173	mutex_lock(&of_mutex);
 174	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
 175	if (!of_kset) {
 176		mutex_unlock(&of_mutex);
 177		pr_err("failed to register existing nodes\n");
 178		return;
 179	}
 180	for_each_of_allnodes(np) {
 181		__of_attach_node_sysfs(np);
 182		if (np->phandle && !phandle_cache[of_phandle_cache_hash(np->phandle)])
 183			phandle_cache[of_phandle_cache_hash(np->phandle)] = np;
 184	}
 185	mutex_unlock(&of_mutex);
 186
 187	/* Symlink in /proc as required by userspace ABI */
 188	if (of_root)
 189		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
 190}
 191
 192static struct property *__of_find_property(const struct device_node *np,
 193					   const char *name, int *lenp)
 194{
 195	struct property *pp;
 196
 197	if (!np)
 198		return NULL;
 199
 200	for (pp = np->properties; pp; pp = pp->next) {
 201		if (of_prop_cmp(pp->name, name) == 0) {
 202			if (lenp)
 203				*lenp = pp->length;
 204			break;
 205		}
 206	}
 207
 208	return pp;
 209}
 210
 211struct property *of_find_property(const struct device_node *np,
 212				  const char *name,
 213				  int *lenp)
 214{
 215	struct property *pp;
 216	unsigned long flags;
 217
 218	raw_spin_lock_irqsave(&devtree_lock, flags);
 219	pp = __of_find_property(np, name, lenp);
 220	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 221
 222	return pp;
 223}
 224EXPORT_SYMBOL(of_find_property);
 225
 226struct device_node *__of_find_all_nodes(struct device_node *prev)
 227{
 228	struct device_node *np;
 229	if (!prev) {
 230		np = of_root;
 231	} else if (prev->child) {
 232		np = prev->child;
 233	} else {
 234		/* Walk back up looking for a sibling, or the end of the structure */
 235		np = prev;
 236		while (np->parent && !np->sibling)
 237			np = np->parent;
 238		np = np->sibling; /* Might be null at the end of the tree */
 239	}
 240	return np;
 241}
 242
 243/**
 244 * of_find_all_nodes - Get next node in global list
 245 * @prev:	Previous node or NULL to start iteration
 246 *		of_node_put() will be called on it
 247 *
 248 * Return: A node pointer with refcount incremented, use
 249 * of_node_put() on it when done.
 250 */
 251struct device_node *of_find_all_nodes(struct device_node *prev)
 252{
 253	struct device_node *np;
 254	unsigned long flags;
 255
 256	raw_spin_lock_irqsave(&devtree_lock, flags);
 257	np = __of_find_all_nodes(prev);
 258	of_node_get(np);
 259	of_node_put(prev);
 260	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 261	return np;
 262}
 263EXPORT_SYMBOL(of_find_all_nodes);
 264
 265/*
 266 * Find a property with a given name for a given node
 267 * and return the value.
 268 */
 269const void *__of_get_property(const struct device_node *np,
 270			      const char *name, int *lenp)
 271{
 272	struct property *pp = __of_find_property(np, name, lenp);
 273
 274	return pp ? pp->value : NULL;
 275}
 276
 277/*
 278 * Find a property with a given name for a given node
 279 * and return the value.
 280 */
 281const void *of_get_property(const struct device_node *np, const char *name,
 282			    int *lenp)
 283{
 284	struct property *pp = of_find_property(np, name, lenp);
 285
 286	return pp ? pp->value : NULL;
 287}
 288EXPORT_SYMBOL(of_get_property);
 289
 290/*
 291 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
 292 *
 293 * @cpu: logical cpu index of a core/thread
 294 * @phys_id: physical identifier of a core/thread
 295 *
 296 * CPU logical to physical index mapping is architecture specific.
 297 * However this __weak function provides a default match of physical
 298 * id to logical cpu index. phys_id provided here is usually values read
 299 * from the device tree which must match the hardware internal registers.
 300 *
 301 * Returns true if the physical identifier and the logical cpu index
 302 * correspond to the same core/thread, false otherwise.
 303 */
 304bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
 305{
 306	return (u32)phys_id == cpu;
 307}
 308
 309/*
 310 * Checks if the given "prop_name" property holds the physical id of the
 311 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
 312 * NULL, local thread number within the core is returned in it.
 313 */
 314static bool __of_find_n_match_cpu_property(struct device_node *cpun,
 315			const char *prop_name, int cpu, unsigned int *thread)
 316{
 317	const __be32 *cell;
 318	int ac, prop_len, tid;
 319	u64 hwid;
 320
 321	ac = of_n_addr_cells(cpun);
 322	cell = of_get_property(cpun, prop_name, &prop_len);
 323	if (!cell && !ac && arch_match_cpu_phys_id(cpu, 0))
 324		return true;
 325	if (!cell || !ac)
 326		return false;
 327	prop_len /= sizeof(*cell) * ac;
 328	for (tid = 0; tid < prop_len; tid++) {
 329		hwid = of_read_number(cell, ac);
 330		if (arch_match_cpu_phys_id(cpu, hwid)) {
 331			if (thread)
 332				*thread = tid;
 333			return true;
 334		}
 335		cell += ac;
 336	}
 337	return false;
 338}
 339
 340/*
 341 * arch_find_n_match_cpu_physical_id - See if the given device node is
 342 * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
 343 * else false.  If 'thread' is non-NULL, the local thread number within the
 344 * core is returned in it.
 345 */
 346bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
 347					      int cpu, unsigned int *thread)
 348{
 349	/* Check for non-standard "ibm,ppc-interrupt-server#s" property
 350	 * for thread ids on PowerPC. If it doesn't exist fallback to
 351	 * standard "reg" property.
 352	 */
 353	if (IS_ENABLED(CONFIG_PPC) &&
 354	    __of_find_n_match_cpu_property(cpun,
 355					   "ibm,ppc-interrupt-server#s",
 356					   cpu, thread))
 357		return true;
 358
 359	return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
 360}
 361
 362/**
 363 * of_get_cpu_node - Get device node associated with the given logical CPU
 364 *
 365 * @cpu: CPU number(logical index) for which device node is required
 366 * @thread: if not NULL, local thread number within the physical core is
 367 *          returned
 368 *
 369 * The main purpose of this function is to retrieve the device node for the
 370 * given logical CPU index. It should be used to initialize the of_node in
 371 * cpu device. Once of_node in cpu device is populated, all the further
 372 * references can use that instead.
 373 *
 374 * CPU logical to physical index mapping is architecture specific and is built
 375 * before booting secondary cores. This function uses arch_match_cpu_phys_id
 376 * which can be overridden by architecture specific implementation.
 377 *
 378 * Return: A node pointer for the logical cpu with refcount incremented, use
 379 * of_node_put() on it when done. Returns NULL if not found.
 380 */
 381struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
 382{
 383	struct device_node *cpun;
 384
 385	for_each_of_cpu_node(cpun) {
 386		if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
 387			return cpun;
 388	}
 389	return NULL;
 390}
 391EXPORT_SYMBOL(of_get_cpu_node);
 392
 393/**
 394 * of_cpu_node_to_id: Get the logical CPU number for a given device_node
 395 *
 396 * @cpu_node: Pointer to the device_node for CPU.
 397 *
 398 * Return: The logical CPU number of the given CPU device_node or -ENODEV if the
 399 * CPU is not found.
 400 */
 401int of_cpu_node_to_id(struct device_node *cpu_node)
 402{
 403	int cpu;
 404	bool found = false;
 405	struct device_node *np;
 406
 407	for_each_possible_cpu(cpu) {
 408		np = of_cpu_device_node_get(cpu);
 409		found = (cpu_node == np);
 410		of_node_put(np);
 411		if (found)
 412			return cpu;
 413	}
 414
 415	return -ENODEV;
 416}
 417EXPORT_SYMBOL(of_cpu_node_to_id);
 418
 419/**
 420 * of_get_cpu_state_node - Get CPU's idle state node at the given index
 421 *
 422 * @cpu_node: The device node for the CPU
 423 * @index: The index in the list of the idle states
 424 *
 425 * Two generic methods can be used to describe a CPU's idle states, either via
 426 * a flattened description through the "cpu-idle-states" binding or via the
 427 * hierarchical layout, using the "power-domains" and the "domain-idle-states"
 428 * bindings. This function check for both and returns the idle state node for
 429 * the requested index.
 430 *
 431 * Return: An idle state node if found at @index. The refcount is incremented
 432 * for it, so call of_node_put() on it when done. Returns NULL if not found.
 433 */
 434struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
 435					  int index)
 436{
 437	struct of_phandle_args args;
 438	int err;
 439
 440	err = of_parse_phandle_with_args(cpu_node, "power-domains",
 441					"#power-domain-cells", 0, &args);
 442	if (!err) {
 443		struct device_node *state_node =
 444			of_parse_phandle(args.np, "domain-idle-states", index);
 445
 446		of_node_put(args.np);
 447		if (state_node)
 448			return state_node;
 449	}
 450
 451	return of_parse_phandle(cpu_node, "cpu-idle-states", index);
 452}
 453EXPORT_SYMBOL(of_get_cpu_state_node);
 454
 455/**
 456 * __of_device_is_compatible() - Check if the node matches given constraints
 457 * @device: pointer to node
 458 * @compat: required compatible string, NULL or "" for any match
 459 * @type: required device_type value, NULL or "" for any match
 460 * @name: required node name, NULL or "" for any match
 461 *
 462 * Checks if the given @compat, @type and @name strings match the
 463 * properties of the given @device. A constraints can be skipped by
 464 * passing NULL or an empty string as the constraint.
 465 *
 466 * Returns 0 for no match, and a positive integer on match. The return
 467 * value is a relative score with larger values indicating better
 468 * matches. The score is weighted for the most specific compatible value
 469 * to get the highest score. Matching type is next, followed by matching
 470 * name. Practically speaking, this results in the following priority
 471 * order for matches:
 472 *
 473 * 1. specific compatible && type && name
 474 * 2. specific compatible && type
 475 * 3. specific compatible && name
 476 * 4. specific compatible
 477 * 5. general compatible && type && name
 478 * 6. general compatible && type
 479 * 7. general compatible && name
 480 * 8. general compatible
 481 * 9. type && name
 482 * 10. type
 483 * 11. name
 484 */
 485static int __of_device_is_compatible(const struct device_node *device,
 486				     const char *compat, const char *type, const char *name)
 487{
 488	struct property *prop;
 489	const char *cp;
 490	int index = 0, score = 0;
 491
 492	/* Compatible match has highest priority */
 493	if (compat && compat[0]) {
 494		prop = __of_find_property(device, "compatible", NULL);
 495		for (cp = of_prop_next_string(prop, NULL); cp;
 496		     cp = of_prop_next_string(prop, cp), index++) {
 497			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
 498				score = INT_MAX/2 - (index << 2);
 499				break;
 500			}
 501		}
 502		if (!score)
 503			return 0;
 504	}
 505
 506	/* Matching type is better than matching name */
 507	if (type && type[0]) {
 508		if (!__of_node_is_type(device, type))
 509			return 0;
 510		score += 2;
 511	}
 512
 513	/* Matching name is a bit better than not */
 514	if (name && name[0]) {
 515		if (!of_node_name_eq(device, name))
 516			return 0;
 517		score++;
 518	}
 519
 520	return score;
 521}
 522
 523/** Checks if the given "compat" string matches one of the strings in
 524 * the device's "compatible" property
 525 */
 526int of_device_is_compatible(const struct device_node *device,
 527		const char *compat)
 528{
 529	unsigned long flags;
 530	int res;
 531
 532	raw_spin_lock_irqsave(&devtree_lock, flags);
 533	res = __of_device_is_compatible(device, compat, NULL, NULL);
 534	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 535	return res;
 536}
 537EXPORT_SYMBOL(of_device_is_compatible);
 538
 539/** Checks if the device is compatible with any of the entries in
 540 *  a NULL terminated array of strings. Returns the best match
 541 *  score or 0.
 542 */
 543int of_device_compatible_match(struct device_node *device,
 544			       const char *const *compat)
 545{
 546	unsigned int tmp, score = 0;
 547
 548	if (!compat)
 549		return 0;
 550
 551	while (*compat) {
 552		tmp = of_device_is_compatible(device, *compat);
 553		if (tmp > score)
 554			score = tmp;
 555		compat++;
 556	}
 557
 558	return score;
 559}
 
 560
 561/**
 562 * of_machine_is_compatible - Test root of device tree for a given compatible value
 563 * @compat: compatible string to look for in root node's compatible property.
 564 *
 565 * Return: A positive integer if the root node has the given value in its
 566 * compatible property.
 567 */
 568int of_machine_is_compatible(const char *compat)
 569{
 570	struct device_node *root;
 571	int rc = 0;
 572
 573	root = of_find_node_by_path("/");
 574	if (root) {
 575		rc = of_device_is_compatible(root, compat);
 576		of_node_put(root);
 577	}
 578	return rc;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 579}
 580EXPORT_SYMBOL(of_machine_is_compatible);
 581
 582/**
 583 *  __of_device_is_available - check if a device is available for use
 584 *
 585 *  @device: Node to check for availability, with locks already held
 586 *
 587 *  Return: True if the status property is absent or set to "okay" or "ok",
 588 *  false otherwise
 589 */
 590static bool __of_device_is_available(const struct device_node *device)
 591{
 592	const char *status;
 593	int statlen;
 594
 595	if (!device)
 596		return false;
 597
 598	status = __of_get_property(device, "status", &statlen);
 599	if (status == NULL)
 600		return true;
 601
 602	if (statlen > 0) {
 603		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
 604			return true;
 605	}
 
 
 
 
 
 
 606
 607	return false;
 608}
 609
 610/**
 611 *  of_device_is_available - check if a device is available for use
 612 *
 613 *  @device: Node to check for availability
 614 *
 615 *  Return: True if the status property is absent or set to "okay" or "ok",
 616 *  false otherwise
 617 */
 618bool of_device_is_available(const struct device_node *device)
 619{
 620	unsigned long flags;
 621	bool res;
 622
 623	raw_spin_lock_irqsave(&devtree_lock, flags);
 624	res = __of_device_is_available(device);
 625	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 626	return res;
 627
 628}
 629EXPORT_SYMBOL(of_device_is_available);
 630
 631/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 632 *  of_device_is_big_endian - check if a device has BE registers
 633 *
 634 *  @device: Node to check for endianness
 635 *
 636 *  Return: True if the device has a "big-endian" property, or if the kernel
 637 *  was compiled for BE *and* the device has a "native-endian" property.
 638 *  Returns false otherwise.
 639 *
 640 *  Callers would nominally use ioread32be/iowrite32be if
 641 *  of_device_is_big_endian() == true, or readl/writel otherwise.
 642 */
 643bool of_device_is_big_endian(const struct device_node *device)
 644{
 645	if (of_property_read_bool(device, "big-endian"))
 646		return true;
 647	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
 648	    of_property_read_bool(device, "native-endian"))
 649		return true;
 650	return false;
 651}
 652EXPORT_SYMBOL(of_device_is_big_endian);
 653
 654/**
 655 * of_get_parent - Get a node's parent if any
 656 * @node:	Node to get parent
 657 *
 658 * Return: A node pointer with refcount incremented, use
 659 * of_node_put() on it when done.
 660 */
 661struct device_node *of_get_parent(const struct device_node *node)
 662{
 663	struct device_node *np;
 664	unsigned long flags;
 665
 666	if (!node)
 667		return NULL;
 668
 669	raw_spin_lock_irqsave(&devtree_lock, flags);
 670	np = of_node_get(node->parent);
 671	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 672	return np;
 673}
 674EXPORT_SYMBOL(of_get_parent);
 675
 676/**
 677 * of_get_next_parent - Iterate to a node's parent
 678 * @node:	Node to get parent of
 679 *
 680 * This is like of_get_parent() except that it drops the
 681 * refcount on the passed node, making it suitable for iterating
 682 * through a node's parents.
 683 *
 684 * Return: A node pointer with refcount incremented, use
 685 * of_node_put() on it when done.
 686 */
 687struct device_node *of_get_next_parent(struct device_node *node)
 688{
 689	struct device_node *parent;
 690	unsigned long flags;
 691
 692	if (!node)
 693		return NULL;
 694
 695	raw_spin_lock_irqsave(&devtree_lock, flags);
 696	parent = of_node_get(node->parent);
 697	of_node_put(node);
 698	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 699	return parent;
 700}
 701EXPORT_SYMBOL(of_get_next_parent);
 702
 703static struct device_node *__of_get_next_child(const struct device_node *node,
 704						struct device_node *prev)
 705{
 706	struct device_node *next;
 707
 708	if (!node)
 709		return NULL;
 710
 711	next = prev ? prev->sibling : node->child;
 712	for (; next; next = next->sibling)
 713		if (of_node_get(next))
 714			break;
 715	of_node_put(prev);
 716	return next;
 717}
 718#define __for_each_child_of_node(parent, child) \
 719	for (child = __of_get_next_child(parent, NULL); child != NULL; \
 720	     child = __of_get_next_child(parent, child))
 721
 722/**
 723 * of_get_next_child - Iterate a node childs
 724 * @node:	parent node
 725 * @prev:	previous child of the parent node, or NULL to get first
 726 *
 727 * Return: A node pointer with refcount incremented, use of_node_put() on
 728 * it when done. Returns NULL when prev is the last child. Decrements the
 729 * refcount of prev.
 730 */
 731struct device_node *of_get_next_child(const struct device_node *node,
 732	struct device_node *prev)
 733{
 734	struct device_node *next;
 735	unsigned long flags;
 736
 737	raw_spin_lock_irqsave(&devtree_lock, flags);
 738	next = __of_get_next_child(node, prev);
 739	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 740	return next;
 741}
 742EXPORT_SYMBOL(of_get_next_child);
 743
 744/**
 745 * of_get_next_available_child - Find the next available child node
 746 * @node:	parent node
 747 * @prev:	previous child of the parent node, or NULL to get first
 748 *
 749 * This function is like of_get_next_child(), except that it
 750 * automatically skips any disabled nodes (i.e. status = "disabled").
 751 */
 752struct device_node *of_get_next_available_child(const struct device_node *node,
 753	struct device_node *prev)
 754{
 755	struct device_node *next;
 756	unsigned long flags;
 757
 758	if (!node)
 759		return NULL;
 760
 761	raw_spin_lock_irqsave(&devtree_lock, flags);
 762	next = prev ? prev->sibling : node->child;
 763	for (; next; next = next->sibling) {
 764		if (!__of_device_is_available(next))
 765			continue;
 766		if (of_node_get(next))
 767			break;
 768	}
 769	of_node_put(prev);
 770	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 771	return next;
 772}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 773EXPORT_SYMBOL(of_get_next_available_child);
 774
 775/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 776 * of_get_next_cpu_node - Iterate on cpu nodes
 777 * @prev:	previous child of the /cpus node, or NULL to get first
 778 *
 
 
 
 779 * Return: A cpu node pointer with refcount incremented, use of_node_put()
 780 * on it when done. Returns NULL when prev is the last child. Decrements
 781 * the refcount of prev.
 782 */
 783struct device_node *of_get_next_cpu_node(struct device_node *prev)
 784{
 785	struct device_node *next = NULL;
 786	unsigned long flags;
 787	struct device_node *node;
 788
 789	if (!prev)
 790		node = of_find_node_by_path("/cpus");
 791
 792	raw_spin_lock_irqsave(&devtree_lock, flags);
 793	if (prev)
 794		next = prev->sibling;
 795	else if (node) {
 796		next = node->child;
 797		of_node_put(node);
 798	}
 799	for (; next; next = next->sibling) {
 
 
 800		if (!(of_node_name_eq(next, "cpu") ||
 801		      __of_node_is_type(next, "cpu")))
 802			continue;
 803		if (of_node_get(next))
 804			break;
 805	}
 806	of_node_put(prev);
 807	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 808	return next;
 809}
 810EXPORT_SYMBOL(of_get_next_cpu_node);
 811
 812/**
 813 * of_get_compatible_child - Find compatible child node
 814 * @parent:	parent node
 815 * @compatible:	compatible string
 816 *
 817 * Lookup child node whose compatible property contains the given compatible
 818 * string.
 819 *
 820 * Return: a node pointer with refcount incremented, use of_node_put() on it
 821 * when done; or NULL if not found.
 822 */
 823struct device_node *of_get_compatible_child(const struct device_node *parent,
 824				const char *compatible)
 825{
 826	struct device_node *child;
 827
 828	for_each_child_of_node(parent, child) {
 829		if (of_device_is_compatible(child, compatible))
 830			break;
 831	}
 832
 833	return child;
 834}
 835EXPORT_SYMBOL(of_get_compatible_child);
 836
 837/**
 838 * of_get_child_by_name - Find the child node by name for a given parent
 839 * @node:	parent node
 840 * @name:	child name to look for.
 841 *
 842 * This function looks for child node for given matching name
 843 *
 844 * Return: A node pointer if found, with refcount incremented, use
 845 * of_node_put() on it when done.
 846 * Returns NULL if node is not found.
 847 */
 848struct device_node *of_get_child_by_name(const struct device_node *node,
 849				const char *name)
 850{
 851	struct device_node *child;
 852
 853	for_each_child_of_node(node, child)
 854		if (of_node_name_eq(child, name))
 855			break;
 856	return child;
 857}
 858EXPORT_SYMBOL(of_get_child_by_name);
 859
 860struct device_node *__of_find_node_by_path(struct device_node *parent,
 861						const char *path)
 862{
 863	struct device_node *child;
 864	int len;
 865
 866	len = strcspn(path, "/:");
 867	if (!len)
 868		return NULL;
 869
 870	__for_each_child_of_node(parent, child) {
 871		const char *name = kbasename(child->full_name);
 872		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
 873			return child;
 874	}
 875	return NULL;
 876}
 877
 878struct device_node *__of_find_node_by_full_path(struct device_node *node,
 879						const char *path)
 880{
 881	const char *separator = strchr(path, ':');
 882
 883	while (node && *path == '/') {
 884		struct device_node *tmp = node;
 885
 886		path++; /* Increment past '/' delimiter */
 887		node = __of_find_node_by_path(node, path);
 888		of_node_put(tmp);
 889		path = strchrnul(path, '/');
 890		if (separator && separator < path)
 891			break;
 892	}
 893	return node;
 894}
 895
 896/**
 897 * of_find_node_opts_by_path - Find a node matching a full OF path
 898 * @path: Either the full path to match, or if the path does not
 899 *       start with '/', the name of a property of the /aliases
 900 *       node (an alias).  In the case of an alias, the node
 901 *       matching the alias' value will be returned.
 902 * @opts: Address of a pointer into which to store the start of
 903 *       an options string appended to the end of the path with
 904 *       a ':' separator.
 905 *
 906 * Valid paths:
 907 *  * /foo/bar	Full path
 908 *  * foo	Valid alias
 909 *  * foo/bar	Valid alias + relative path
 910 *
 911 * Return: A node pointer with refcount incremented, use
 912 * of_node_put() on it when done.
 913 */
 914struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
 915{
 916	struct device_node *np = NULL;
 917	struct property *pp;
 918	unsigned long flags;
 919	const char *separator = strchr(path, ':');
 920
 921	if (opts)
 922		*opts = separator ? separator + 1 : NULL;
 923
 924	if (strcmp(path, "/") == 0)
 925		return of_node_get(of_root);
 926
 927	/* The path could begin with an alias */
 928	if (*path != '/') {
 929		int len;
 930		const char *p = separator;
 931
 932		if (!p)
 933			p = strchrnul(path, '/');
 934		len = p - path;
 935
 936		/* of_aliases must not be NULL */
 937		if (!of_aliases)
 938			return NULL;
 939
 940		for_each_property_of_node(of_aliases, pp) {
 941			if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
 942				np = of_find_node_by_path(pp->value);
 943				break;
 944			}
 945		}
 946		if (!np)
 947			return NULL;
 948		path = p;
 949	}
 950
 951	/* Step down the tree matching path components */
 952	raw_spin_lock_irqsave(&devtree_lock, flags);
 953	if (!np)
 954		np = of_node_get(of_root);
 955	np = __of_find_node_by_full_path(np, path);
 956	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 957	return np;
 958}
 959EXPORT_SYMBOL(of_find_node_opts_by_path);
 960
 961/**
 962 * of_find_node_by_name - Find a node by its "name" property
 963 * @from:	The node to start searching from or NULL; the node
 964 *		you pass will not be searched, only the next one
 965 *		will. Typically, you pass what the previous call
 966 *		returned. of_node_put() will be called on @from.
 967 * @name:	The name string to match against
 968 *
 969 * Return: A node pointer with refcount incremented, use
 970 * of_node_put() on it when done.
 971 */
 972struct device_node *of_find_node_by_name(struct device_node *from,
 973	const char *name)
 974{
 975	struct device_node *np;
 976	unsigned long flags;
 977
 978	raw_spin_lock_irqsave(&devtree_lock, flags);
 979	for_each_of_allnodes_from(from, np)
 980		if (of_node_name_eq(np, name) && of_node_get(np))
 981			break;
 982	of_node_put(from);
 983	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 984	return np;
 985}
 986EXPORT_SYMBOL(of_find_node_by_name);
 987
 988/**
 989 * of_find_node_by_type - Find a node by its "device_type" property
 990 * @from:	The node to start searching from, or NULL to start searching
 991 *		the entire device tree. The node you pass will not be
 992 *		searched, only the next one will; typically, you pass
 993 *		what the previous call returned. of_node_put() will be
 994 *		called on from for you.
 995 * @type:	The type string to match against
 996 *
 997 * Return: A node pointer with refcount incremented, use
 998 * of_node_put() on it when done.
 999 */
1000struct device_node *of_find_node_by_type(struct device_node *from,
1001	const char *type)
1002{
1003	struct device_node *np;
1004	unsigned long flags;
1005
1006	raw_spin_lock_irqsave(&devtree_lock, flags);
1007	for_each_of_allnodes_from(from, np)
1008		if (__of_node_is_type(np, type) && of_node_get(np))
1009			break;
1010	of_node_put(from);
1011	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1012	return np;
1013}
1014EXPORT_SYMBOL(of_find_node_by_type);
1015
1016/**
1017 * of_find_compatible_node - Find a node based on type and one of the
1018 *                                tokens in its "compatible" property
1019 * @from:	The node to start searching from or NULL, the node
1020 *		you pass will not be searched, only the next one
1021 *		will; typically, you pass what the previous call
1022 *		returned. of_node_put() will be called on it
1023 * @type:	The type string to match "device_type" or NULL to ignore
1024 * @compatible:	The string to match to one of the tokens in the device
1025 *		"compatible" list.
1026 *
1027 * Return: A node pointer with refcount incremented, use
1028 * of_node_put() on it when done.
1029 */
1030struct device_node *of_find_compatible_node(struct device_node *from,
1031	const char *type, const char *compatible)
1032{
1033	struct device_node *np;
1034	unsigned long flags;
1035
1036	raw_spin_lock_irqsave(&devtree_lock, flags);
1037	for_each_of_allnodes_from(from, np)
1038		if (__of_device_is_compatible(np, compatible, type, NULL) &&
1039		    of_node_get(np))
1040			break;
1041	of_node_put(from);
1042	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1043	return np;
1044}
1045EXPORT_SYMBOL(of_find_compatible_node);
1046
1047/**
1048 * of_find_node_with_property - Find a node which has a property with
1049 *                              the given name.
1050 * @from:	The node to start searching from or NULL, the node
1051 *		you pass will not be searched, only the next one
1052 *		will; typically, you pass what the previous call
1053 *		returned. of_node_put() will be called on it
1054 * @prop_name:	The name of the property to look for.
1055 *
1056 * Return: A node pointer with refcount incremented, use
1057 * of_node_put() on it when done.
1058 */
1059struct device_node *of_find_node_with_property(struct device_node *from,
1060	const char *prop_name)
1061{
1062	struct device_node *np;
1063	struct property *pp;
1064	unsigned long flags;
1065
1066	raw_spin_lock_irqsave(&devtree_lock, flags);
1067	for_each_of_allnodes_from(from, np) {
1068		for (pp = np->properties; pp; pp = pp->next) {
1069			if (of_prop_cmp(pp->name, prop_name) == 0) {
1070				of_node_get(np);
1071				goto out;
1072			}
1073		}
1074	}
1075out:
1076	of_node_put(from);
1077	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1078	return np;
1079}
1080EXPORT_SYMBOL(of_find_node_with_property);
1081
1082static
1083const struct of_device_id *__of_match_node(const struct of_device_id *matches,
1084					   const struct device_node *node)
1085{
1086	const struct of_device_id *best_match = NULL;
1087	int score, best_score = 0;
1088
1089	if (!matches)
1090		return NULL;
1091
1092	for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
1093		score = __of_device_is_compatible(node, matches->compatible,
1094						  matches->type, matches->name);
1095		if (score > best_score) {
1096			best_match = matches;
1097			best_score = score;
1098		}
1099	}
1100
1101	return best_match;
1102}
1103
1104/**
1105 * of_match_node - Tell if a device_node has a matching of_match structure
1106 * @matches:	array of of device match structures to search in
1107 * @node:	the of device structure to match against
1108 *
1109 * Low level utility function used by device matching.
1110 */
1111const struct of_device_id *of_match_node(const struct of_device_id *matches,
1112					 const struct device_node *node)
1113{
1114	const struct of_device_id *match;
1115	unsigned long flags;
1116
1117	raw_spin_lock_irqsave(&devtree_lock, flags);
1118	match = __of_match_node(matches, node);
1119	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1120	return match;
1121}
1122EXPORT_SYMBOL(of_match_node);
1123
1124/**
1125 * of_find_matching_node_and_match - Find a node based on an of_device_id
1126 *				     match table.
1127 * @from:	The node to start searching from or NULL, the node
1128 *		you pass will not be searched, only the next one
1129 *		will; typically, you pass what the previous call
1130 *		returned. of_node_put() will be called on it
1131 * @matches:	array of of device match structures to search in
1132 * @match:	Updated to point at the matches entry which matched
1133 *
1134 * Return: A node pointer with refcount incremented, use
1135 * of_node_put() on it when done.
1136 */
1137struct device_node *of_find_matching_node_and_match(struct device_node *from,
1138					const struct of_device_id *matches,
1139					const struct of_device_id **match)
1140{
1141	struct device_node *np;
1142	const struct of_device_id *m;
1143	unsigned long flags;
1144
1145	if (match)
1146		*match = NULL;
1147
1148	raw_spin_lock_irqsave(&devtree_lock, flags);
1149	for_each_of_allnodes_from(from, np) {
1150		m = __of_match_node(matches, np);
1151		if (m && of_node_get(np)) {
1152			if (match)
1153				*match = m;
1154			break;
1155		}
1156	}
1157	of_node_put(from);
1158	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1159	return np;
1160}
1161EXPORT_SYMBOL(of_find_matching_node_and_match);
1162
1163/**
1164 * of_modalias_node - Lookup appropriate modalias for a device node
 
1165 * @node:	pointer to a device tree node
1166 * @modalias:	Pointer to buffer that modalias value will be copied into
1167 * @len:	Length of modalias value
1168 *
1169 * Based on the value of the compatible property, this routine will attempt
1170 * to choose an appropriate modalias value for a particular device tree node.
1171 * It does this by stripping the manufacturer prefix (as delimited by a ',')
1172 * from the first entry in the compatible list property.
1173 *
 
 
 
1174 * Return: This routine returns 0 on success, <0 on failure.
1175 */
1176int of_modalias_node(struct device_node *node, char *modalias, int len)
1177{
1178	const char *compatible, *p;
1179	int cplen;
1180
1181	compatible = of_get_property(node, "compatible", &cplen);
1182	if (!compatible || strlen(compatible) > cplen)
1183		return -ENODEV;
1184	p = strchr(compatible, ',');
1185	strlcpy(modalias, p ? p + 1 : compatible, len);
1186	return 0;
1187}
1188EXPORT_SYMBOL_GPL(of_modalias_node);
1189
1190/**
1191 * of_find_node_by_phandle - Find a node given a phandle
1192 * @handle:	phandle of the node to find
1193 *
1194 * Return: A node pointer with refcount incremented, use
1195 * of_node_put() on it when done.
1196 */
1197struct device_node *of_find_node_by_phandle(phandle handle)
1198{
1199	struct device_node *np = NULL;
1200	unsigned long flags;
1201	u32 handle_hash;
1202
1203	if (!handle)
1204		return NULL;
1205
1206	handle_hash = of_phandle_cache_hash(handle);
1207
1208	raw_spin_lock_irqsave(&devtree_lock, flags);
1209
1210	if (phandle_cache[handle_hash] &&
1211	    handle == phandle_cache[handle_hash]->phandle)
1212		np = phandle_cache[handle_hash];
1213
1214	if (!np) {
1215		for_each_of_allnodes(np)
1216			if (np->phandle == handle &&
1217			    !of_node_check_flag(np, OF_DETACHED)) {
1218				phandle_cache[handle_hash] = np;
1219				break;
1220			}
1221	}
1222
1223	of_node_get(np);
1224	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1225	return np;
1226}
1227EXPORT_SYMBOL(of_find_node_by_phandle);
1228
1229void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1230{
1231	int i;
1232	printk("%s %pOF", msg, args->np);
1233	for (i = 0; i < args->args_count; i++) {
1234		const char delim = i ? ',' : ':';
1235
1236		pr_cont("%c%08x", delim, args->args[i]);
1237	}
1238	pr_cont("\n");
1239}
1240
1241int of_phandle_iterator_init(struct of_phandle_iterator *it,
1242		const struct device_node *np,
1243		const char *list_name,
1244		const char *cells_name,
1245		int cell_count)
1246{
1247	const __be32 *list;
1248	int size;
1249
1250	memset(it, 0, sizeof(*it));
1251
1252	/*
1253	 * one of cell_count or cells_name must be provided to determine the
1254	 * argument length.
1255	 */
1256	if (cell_count < 0 && !cells_name)
1257		return -EINVAL;
1258
1259	list = of_get_property(np, list_name, &size);
1260	if (!list)
1261		return -ENOENT;
1262
1263	it->cells_name = cells_name;
1264	it->cell_count = cell_count;
1265	it->parent = np;
1266	it->list_end = list + size / sizeof(*list);
1267	it->phandle_end = list;
1268	it->cur = list;
1269
1270	return 0;
1271}
1272EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
1273
1274int of_phandle_iterator_next(struct of_phandle_iterator *it)
1275{
1276	uint32_t count = 0;
1277
1278	if (it->node) {
1279		of_node_put(it->node);
1280		it->node = NULL;
1281	}
1282
1283	if (!it->cur || it->phandle_end >= it->list_end)
1284		return -ENOENT;
1285
1286	it->cur = it->phandle_end;
1287
1288	/* If phandle is 0, then it is an empty entry with no arguments. */
1289	it->phandle = be32_to_cpup(it->cur++);
1290
1291	if (it->phandle) {
1292
1293		/*
1294		 * Find the provider node and parse the #*-cells property to
1295		 * determine the argument length.
1296		 */
1297		it->node = of_find_node_by_phandle(it->phandle);
1298
1299		if (it->cells_name) {
1300			if (!it->node) {
1301				pr_err("%pOF: could not find phandle %d\n",
1302				       it->parent, it->phandle);
1303				goto err;
1304			}
1305
1306			if (of_property_read_u32(it->node, it->cells_name,
1307						 &count)) {
1308				/*
1309				 * If both cell_count and cells_name is given,
1310				 * fall back to cell_count in absence
1311				 * of the cells_name property
1312				 */
1313				if (it->cell_count >= 0) {
1314					count = it->cell_count;
1315				} else {
1316					pr_err("%pOF: could not get %s for %pOF\n",
1317					       it->parent,
1318					       it->cells_name,
1319					       it->node);
1320					goto err;
1321				}
1322			}
1323		} else {
1324			count = it->cell_count;
1325		}
1326
1327		/*
1328		 * Make sure that the arguments actually fit in the remaining
1329		 * property data length
1330		 */
1331		if (it->cur + count > it->list_end) {
1332			pr_err("%pOF: %s = %d found %d\n",
1333			       it->parent, it->cells_name,
1334			       count, it->cell_count);
 
 
 
 
 
1335			goto err;
1336		}
1337	}
1338
1339	it->phandle_end = it->cur + count;
1340	it->cur_count = count;
1341
1342	return 0;
1343
1344err:
1345	if (it->node) {
1346		of_node_put(it->node);
1347		it->node = NULL;
1348	}
1349
1350	return -EINVAL;
1351}
1352EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
1353
1354int of_phandle_iterator_args(struct of_phandle_iterator *it,
1355			     uint32_t *args,
1356			     int size)
1357{
1358	int i, count;
1359
1360	count = it->cur_count;
1361
1362	if (WARN_ON(size < count))
1363		count = size;
1364
1365	for (i = 0; i < count; i++)
1366		args[i] = be32_to_cpup(it->cur++);
1367
1368	return count;
1369}
1370
1371static int __of_parse_phandle_with_args(const struct device_node *np,
1372					const char *list_name,
1373					const char *cells_name,
1374					int cell_count, int index,
1375					struct of_phandle_args *out_args)
1376{
1377	struct of_phandle_iterator it;
1378	int rc, cur_index = 0;
1379
 
 
 
1380	/* Loop over the phandles until all the requested entry is found */
1381	of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1382		/*
1383		 * All of the error cases bail out of the loop, so at
1384		 * this point, the parsing is successful. If the requested
1385		 * index matches, then fill the out_args structure and return,
1386		 * or return -ENOENT for an empty entry.
1387		 */
1388		rc = -ENOENT;
1389		if (cur_index == index) {
1390			if (!it.phandle)
1391				goto err;
1392
1393			if (out_args) {
1394				int c;
1395
1396				c = of_phandle_iterator_args(&it,
1397							     out_args->args,
1398							     MAX_PHANDLE_ARGS);
1399				out_args->np = it.node;
1400				out_args->args_count = c;
1401			} else {
1402				of_node_put(it.node);
1403			}
1404
1405			/* Found it! return success */
1406			return 0;
1407		}
1408
1409		cur_index++;
1410	}
1411
1412	/*
1413	 * Unlock node before returning result; will be one of:
1414	 * -ENOENT : index is for empty phandle
1415	 * -EINVAL : parsing error on data
1416	 */
1417
1418 err:
1419	of_node_put(it.node);
1420	return rc;
1421}
1422
1423/**
1424 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1425 * @np: Pointer to device node holding phandle property
1426 * @phandle_name: Name of property holding a phandle value
1427 * @index: For properties holding a table of phandles, this is the index into
1428 *         the table
1429 *
1430 * Return: The device_node pointer with refcount incremented.  Use
1431 * of_node_put() on it when done.
1432 */
1433struct device_node *of_parse_phandle(const struct device_node *np,
1434				     const char *phandle_name, int index)
1435{
1436	struct of_phandle_args args;
1437
1438	if (index < 0)
1439		return NULL;
1440
1441	if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1442					 index, &args))
1443		return NULL;
1444
1445	return args.np;
1446}
1447EXPORT_SYMBOL(of_parse_phandle);
1448
1449/**
1450 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1451 * @np:		pointer to a device tree node containing a list
1452 * @list_name:	property name that contains a list
1453 * @cells_name:	property name that specifies phandles' arguments count
1454 * @index:	index of a phandle to parse out
1455 * @out_args:	optional pointer to output arguments structure (will be filled)
1456 *
1457 * This function is useful to parse lists of phandles and their arguments.
1458 * Returns 0 on success and fills out_args, on error returns appropriate
1459 * errno value.
1460 *
1461 * Caller is responsible to call of_node_put() on the returned out_args->np
1462 * pointer.
1463 *
1464 * Example::
1465 *
1466 *  phandle1: node1 {
1467 *	#list-cells = <2>;
1468 *  };
1469 *
1470 *  phandle2: node2 {
1471 *	#list-cells = <1>;
1472 *  };
1473 *
1474 *  node3 {
1475 *	list = <&phandle1 1 2 &phandle2 3>;
1476 *  };
1477 *
1478 * To get a device_node of the ``node2`` node you may call this:
1479 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1480 */
1481int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1482				const char *cells_name, int index,
1483				struct of_phandle_args *out_args)
1484{
1485	int cell_count = -1;
1486
1487	if (index < 0)
1488		return -EINVAL;
1489
1490	/* If cells_name is NULL we assume a cell count of 0 */
1491	if (!cells_name)
1492		cell_count = 0;
1493
1494	return __of_parse_phandle_with_args(np, list_name, cells_name,
1495					    cell_count, index, out_args);
1496}
1497EXPORT_SYMBOL(of_parse_phandle_with_args);
1498
1499/**
1500 * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
1501 * @np:		pointer to a device tree node containing a list
1502 * @list_name:	property name that contains a list
1503 * @stem_name:	stem of property names that specify phandles' arguments count
1504 * @index:	index of a phandle to parse out
1505 * @out_args:	optional pointer to output arguments structure (will be filled)
1506 *
1507 * This function is useful to parse lists of phandles and their arguments.
1508 * Returns 0 on success and fills out_args, on error returns appropriate errno
1509 * value. The difference between this function and of_parse_phandle_with_args()
1510 * is that this API remaps a phandle if the node the phandle points to has
1511 * a <@stem_name>-map property.
1512 *
1513 * Caller is responsible to call of_node_put() on the returned out_args->np
1514 * pointer.
1515 *
1516 * Example::
1517 *
1518 *  phandle1: node1 {
1519 *  	#list-cells = <2>;
1520 *  };
1521 *
1522 *  phandle2: node2 {
1523 *  	#list-cells = <1>;
1524 *  };
1525 *
1526 *  phandle3: node3 {
1527 *  	#list-cells = <1>;
1528 *  	list-map = <0 &phandle2 3>,
1529 *  		   <1 &phandle2 2>,
1530 *  		   <2 &phandle1 5 1>;
1531 *  	list-map-mask = <0x3>;
1532 *  };
1533 *
1534 *  node4 {
1535 *  	list = <&phandle1 1 2 &phandle3 0>;
1536 *  };
1537 *
1538 * To get a device_node of the ``node2`` node you may call this:
1539 * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
1540 */
1541int of_parse_phandle_with_args_map(const struct device_node *np,
1542				   const char *list_name,
1543				   const char *stem_name,
1544				   int index, struct of_phandle_args *out_args)
1545{
1546	char *cells_name, *map_name = NULL, *mask_name = NULL;
1547	char *pass_name = NULL;
1548	struct device_node *cur, *new = NULL;
1549	const __be32 *map, *mask, *pass;
1550	static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
1551	static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
1552	__be32 initial_match_array[MAX_PHANDLE_ARGS];
1553	const __be32 *match_array = initial_match_array;
1554	int i, ret, map_len, match;
1555	u32 list_size, new_size;
1556
1557	if (index < 0)
1558		return -EINVAL;
1559
1560	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
1561	if (!cells_name)
1562		return -ENOMEM;
1563
1564	ret = -ENOMEM;
1565	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
1566	if (!map_name)
1567		goto free;
1568
1569	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
1570	if (!mask_name)
1571		goto free;
1572
1573	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
1574	if (!pass_name)
1575		goto free;
1576
1577	ret = __of_parse_phandle_with_args(np, list_name, cells_name, -1, index,
1578					   out_args);
1579	if (ret)
1580		goto free;
1581
1582	/* Get the #<list>-cells property */
1583	cur = out_args->np;
1584	ret = of_property_read_u32(cur, cells_name, &list_size);
1585	if (ret < 0)
1586		goto put;
1587
1588	/* Precalculate the match array - this simplifies match loop */
1589	for (i = 0; i < list_size; i++)
1590		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
1591
1592	ret = -EINVAL;
1593	while (cur) {
1594		/* Get the <list>-map property */
1595		map = of_get_property(cur, map_name, &map_len);
1596		if (!map) {
1597			ret = 0;
1598			goto free;
1599		}
1600		map_len /= sizeof(u32);
1601
1602		/* Get the <list>-map-mask property (optional) */
1603		mask = of_get_property(cur, mask_name, NULL);
1604		if (!mask)
1605			mask = dummy_mask;
1606		/* Iterate through <list>-map property */
1607		match = 0;
1608		while (map_len > (list_size + 1) && !match) {
1609			/* Compare specifiers */
1610			match = 1;
1611			for (i = 0; i < list_size; i++, map_len--)
1612				match &= !((match_array[i] ^ *map++) & mask[i]);
1613
1614			of_node_put(new);
1615			new = of_find_node_by_phandle(be32_to_cpup(map));
1616			map++;
1617			map_len--;
1618
1619			/* Check if not found */
1620			if (!new)
1621				goto put;
1622
1623			if (!of_device_is_available(new))
1624				match = 0;
1625
1626			ret = of_property_read_u32(new, cells_name, &new_size);
1627			if (ret)
1628				goto put;
1629
1630			/* Check for malformed properties */
1631			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
1632				goto put;
1633			if (map_len < new_size)
1634				goto put;
1635
1636			/* Move forward by new node's #<list>-cells amount */
1637			map += new_size;
1638			map_len -= new_size;
1639		}
1640		if (!match)
1641			goto put;
1642
1643		/* Get the <list>-map-pass-thru property (optional) */
1644		pass = of_get_property(cur, pass_name, NULL);
1645		if (!pass)
1646			pass = dummy_pass;
1647
1648		/*
1649		 * Successfully parsed a <list>-map translation; copy new
1650		 * specifier into the out_args structure, keeping the
1651		 * bits specified in <list>-map-pass-thru.
1652		 */
1653		match_array = map - new_size;
1654		for (i = 0; i < new_size; i++) {
1655			__be32 val = *(map - new_size + i);
1656
1657			if (i < list_size) {
1658				val &= ~pass[i];
1659				val |= cpu_to_be32(out_args->args[i]) & pass[i];
1660			}
1661
1662			out_args->args[i] = be32_to_cpu(val);
1663		}
1664		out_args->args_count = list_size = new_size;
1665		/* Iterate again with new provider */
1666		out_args->np = new;
1667		of_node_put(cur);
1668		cur = new;
 
1669	}
1670put:
1671	of_node_put(cur);
1672	of_node_put(new);
1673free:
1674	kfree(mask_name);
1675	kfree(map_name);
1676	kfree(cells_name);
1677	kfree(pass_name);
1678
1679	return ret;
1680}
1681EXPORT_SYMBOL(of_parse_phandle_with_args_map);
1682
1683/**
1684 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1685 * @np:		pointer to a device tree node containing a list
1686 * @list_name:	property name that contains a list
1687 * @cell_count: number of argument cells following the phandle
1688 * @index:	index of a phandle to parse out
1689 * @out_args:	optional pointer to output arguments structure (will be filled)
1690 *
1691 * This function is useful to parse lists of phandles and their arguments.
1692 * Returns 0 on success and fills out_args, on error returns appropriate
1693 * errno value.
1694 *
1695 * Caller is responsible to call of_node_put() on the returned out_args->np
1696 * pointer.
1697 *
1698 * Example::
1699 *
1700 *  phandle1: node1 {
1701 *  };
1702 *
1703 *  phandle2: node2 {
1704 *  };
1705 *
1706 *  node3 {
1707 *  	list = <&phandle1 0 2 &phandle2 2 3>;
1708 *  };
1709 *
1710 * To get a device_node of the ``node2`` node you may call this:
1711 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1712 */
1713int of_parse_phandle_with_fixed_args(const struct device_node *np,
1714				const char *list_name, int cell_count,
1715				int index, struct of_phandle_args *out_args)
1716{
1717	if (index < 0)
1718		return -EINVAL;
1719	return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1720					   index, out_args);
1721}
1722EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1723
1724/**
1725 * of_count_phandle_with_args() - Find the number of phandles references in a property
1726 * @np:		pointer to a device tree node containing a list
1727 * @list_name:	property name that contains a list
1728 * @cells_name:	property name that specifies phandles' arguments count
1729 *
1730 * Return: The number of phandle + argument tuples within a property. It
1731 * is a typical pattern to encode a list of phandle and variable
1732 * arguments into a single property. The number of arguments is encoded
1733 * by a property in the phandle-target node. For example, a gpios
1734 * property would contain a list of GPIO specifies consisting of a
1735 * phandle and 1 or more arguments. The number of arguments are
1736 * determined by the #gpio-cells property in the node pointed to by the
1737 * phandle.
1738 */
1739int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1740				const char *cells_name)
1741{
1742	struct of_phandle_iterator it;
1743	int rc, cur_index = 0;
1744
1745	/*
1746	 * If cells_name is NULL we assume a cell count of 0. This makes
1747	 * counting the phandles trivial as each 32bit word in the list is a
1748	 * phandle and no arguments are to consider. So we don't iterate through
1749	 * the list but just use the length to determine the phandle count.
1750	 */
1751	if (!cells_name) {
1752		const __be32 *list;
1753		int size;
1754
1755		list = of_get_property(np, list_name, &size);
1756		if (!list)
1757			return -ENOENT;
1758
1759		return size / sizeof(*list);
1760	}
1761
1762	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
1763	if (rc)
1764		return rc;
1765
1766	while ((rc = of_phandle_iterator_next(&it)) == 0)
1767		cur_index += 1;
1768
1769	if (rc != -ENOENT)
1770		return rc;
1771
1772	return cur_index;
1773}
1774EXPORT_SYMBOL(of_count_phandle_with_args);
1775
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1776/**
1777 * __of_add_property - Add a property to a node without lock operations
1778 * @np:		Caller's Device Node
1779 * @prop:	Property to add
1780 */
1781int __of_add_property(struct device_node *np, struct property *prop)
1782{
 
 
1783	struct property **next;
1784
 
 
 
 
1785	prop->next = NULL;
1786	next = &np->properties;
1787	while (*next) {
1788		if (strcmp(prop->name, (*next)->name) == 0)
1789			/* duplicate ! don't insert it */
1790			return -EEXIST;
1791
 
1792		next = &(*next)->next;
1793	}
1794	*next = prop;
1795
 
 
 
 
 
 
1796	return 0;
1797}
1798
1799/**
1800 * of_add_property - Add a property to a node
1801 * @np:		Caller's Device Node
1802 * @prop:	Property to add
1803 */
1804int of_add_property(struct device_node *np, struct property *prop)
1805{
1806	unsigned long flags;
1807	int rc;
1808
1809	mutex_lock(&of_mutex);
1810
1811	raw_spin_lock_irqsave(&devtree_lock, flags);
1812	rc = __of_add_property(np, prop);
1813	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1814
1815	if (!rc)
1816		__of_add_property_sysfs(np, prop);
1817
1818	mutex_unlock(&of_mutex);
1819
1820	if (!rc)
1821		of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1822
1823	return rc;
1824}
 
1825
1826int __of_remove_property(struct device_node *np, struct property *prop)
1827{
1828	struct property **next;
 
1829
1830	for (next = &np->properties; *next; next = &(*next)->next) {
1831		if (*next == prop)
1832			break;
 
 
 
 
1833	}
1834	if (*next == NULL)
1835		return -ENODEV;
1836
1837	/* found the node */
1838	*next = prop->next;
1839	prop->next = np->deadprops;
1840	np->deadprops = prop;
1841
 
1842	return 0;
1843}
1844
1845/**
1846 * of_remove_property - Remove a property from a node.
1847 * @np:		Caller's Device Node
1848 * @prop:	Property to remove
1849 *
1850 * Note that we don't actually remove it, since we have given out
1851 * who-knows-how-many pointers to the data using get-property.
1852 * Instead we just move the property to the "dead properties"
1853 * list, so it won't be found any more.
1854 */
1855int of_remove_property(struct device_node *np, struct property *prop)
1856{
1857	unsigned long flags;
1858	int rc;
1859
1860	if (!prop)
1861		return -ENODEV;
1862
1863	mutex_lock(&of_mutex);
1864
1865	raw_spin_lock_irqsave(&devtree_lock, flags);
1866	rc = __of_remove_property(np, prop);
1867	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1868
1869	if (!rc)
1870		__of_remove_property_sysfs(np, prop);
1871
1872	mutex_unlock(&of_mutex);
1873
1874	if (!rc)
1875		of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1876
1877	return rc;
1878}
1879EXPORT_SYMBOL_GPL(of_remove_property);
1880
1881int __of_update_property(struct device_node *np, struct property *newprop,
1882		struct property **oldpropp)
1883{
1884	struct property **next, *oldprop;
 
 
 
 
 
1885
1886	for (next = &np->properties; *next; next = &(*next)->next) {
1887		if (of_prop_cmp((*next)->name, newprop->name) == 0)
1888			break;
1889	}
1890	*oldpropp = oldprop = *next;
1891
1892	if (oldprop) {
1893		/* replace the node */
1894		newprop->next = oldprop->next;
1895		*next = newprop;
1896		oldprop->next = np->deadprops;
1897		np->deadprops = oldprop;
1898	} else {
1899		/* new node */
1900		newprop->next = NULL;
1901		*next = newprop;
1902	}
1903
 
 
 
 
1904	return 0;
1905}
1906
1907/*
1908 * of_update_property - Update a property in a node, if the property does
1909 * not exist, add it.
1910 *
1911 * Note that we don't actually remove it, since we have given out
1912 * who-knows-how-many pointers to the data using get-property.
1913 * Instead we just move the property to the "dead properties" list,
1914 * and add the new property to the property list
1915 */
1916int of_update_property(struct device_node *np, struct property *newprop)
1917{
1918	struct property *oldprop;
1919	unsigned long flags;
1920	int rc;
1921
1922	if (!newprop->name)
1923		return -EINVAL;
1924
1925	mutex_lock(&of_mutex);
1926
1927	raw_spin_lock_irqsave(&devtree_lock, flags);
1928	rc = __of_update_property(np, newprop, &oldprop);
1929	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1930
1931	if (!rc)
1932		__of_update_property_sysfs(np, newprop, oldprop);
1933
1934	mutex_unlock(&of_mutex);
1935
1936	if (!rc)
1937		of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1938
1939	return rc;
1940}
1941
1942static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1943			 int id, const char *stem, int stem_len)
1944{
1945	ap->np = np;
1946	ap->id = id;
1947	strncpy(ap->stem, stem, stem_len);
1948	ap->stem[stem_len] = 0;
1949	list_add_tail(&ap->link, &aliases_lookup);
1950	pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
1951		 ap->alias, ap->stem, ap->id, np);
1952}
1953
1954/**
1955 * of_alias_scan - Scan all properties of the 'aliases' node
1956 * @dt_alloc:	An allocator that provides a virtual address to memory
1957 *		for storing the resulting tree
1958 *
1959 * The function scans all the properties of the 'aliases' node and populates
1960 * the global lookup table with the properties.  It returns the
1961 * number of alias properties found, or an error code in case of failure.
1962 */
1963void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1964{
1965	struct property *pp;
1966
1967	of_aliases = of_find_node_by_path("/aliases");
1968	of_chosen = of_find_node_by_path("/chosen");
1969	if (of_chosen == NULL)
1970		of_chosen = of_find_node_by_path("/chosen@0");
1971
1972	if (of_chosen) {
1973		/* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1974		const char *name = NULL;
1975
1976		if (of_property_read_string(of_chosen, "stdout-path", &name))
1977			of_property_read_string(of_chosen, "linux,stdout-path",
1978						&name);
1979		if (IS_ENABLED(CONFIG_PPC) && !name)
1980			of_property_read_string(of_aliases, "stdout", &name);
1981		if (name)
1982			of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
 
 
1983	}
1984
1985	if (!of_aliases)
1986		return;
1987
1988	for_each_property_of_node(of_aliases, pp) {
1989		const char *start = pp->name;
1990		const char *end = start + strlen(start);
1991		struct device_node *np;
1992		struct alias_prop *ap;
1993		int id, len;
1994
1995		/* Skip those we do not want to proceed */
1996		if (!strcmp(pp->name, "name") ||
1997		    !strcmp(pp->name, "phandle") ||
1998		    !strcmp(pp->name, "linux,phandle"))
1999			continue;
2000
2001		np = of_find_node_by_path(pp->value);
2002		if (!np)
2003			continue;
2004
2005		/* walk the alias backwards to extract the id and work out
2006		 * the 'stem' string */
2007		while (isdigit(*(end-1)) && end > start)
2008			end--;
2009		len = end - start;
2010
2011		if (kstrtoint(end, 10, &id) < 0)
2012			continue;
2013
2014		/* Allocate an alias_prop with enough space for the stem */
2015		ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
2016		if (!ap)
2017			continue;
2018		memset(ap, 0, sizeof(*ap) + len + 1);
2019		ap->alias = start;
2020		of_alias_add(ap, np, id, start, len);
2021	}
2022}
2023
2024/**
2025 * of_alias_get_id - Get alias id for the given device_node
2026 * @np:		Pointer to the given device_node
2027 * @stem:	Alias stem of the given device_node
2028 *
2029 * The function travels the lookup table to get the alias id for the given
2030 * device_node and alias stem.
2031 *
2032 * Return: The alias id if found.
2033 */
2034int of_alias_get_id(struct device_node *np, const char *stem)
2035{
2036	struct alias_prop *app;
2037	int id = -ENODEV;
2038
2039	mutex_lock(&of_mutex);
2040	list_for_each_entry(app, &aliases_lookup, link) {
2041		if (strcmp(app->stem, stem) != 0)
2042			continue;
2043
2044		if (np == app->np) {
2045			id = app->id;
2046			break;
2047		}
2048	}
2049	mutex_unlock(&of_mutex);
2050
2051	return id;
2052}
2053EXPORT_SYMBOL_GPL(of_alias_get_id);
2054
2055/**
2056 * of_alias_get_alias_list - Get alias list for the given device driver
2057 * @matches:	Array of OF device match structures to search in
2058 * @stem:	Alias stem of the given device_node
2059 * @bitmap:	Bitmap field pointer
2060 * @nbits:	Maximum number of alias IDs which can be recorded in bitmap
2061 *
2062 * The function travels the lookup table to record alias ids for the given
2063 * device match structures and alias stem.
2064 *
2065 * Return:	0 or -ENOSYS when !CONFIG_OF or
2066 *		-EOVERFLOW if alias ID is greater then allocated nbits
2067 */
2068int of_alias_get_alias_list(const struct of_device_id *matches,
2069			     const char *stem, unsigned long *bitmap,
2070			     unsigned int nbits)
2071{
2072	struct alias_prop *app;
2073	int ret = 0;
2074
2075	/* Zero bitmap field to make sure that all the time it is clean */
2076	bitmap_zero(bitmap, nbits);
2077
2078	mutex_lock(&of_mutex);
2079	pr_debug("%s: Looking for stem: %s\n", __func__, stem);
2080	list_for_each_entry(app, &aliases_lookup, link) {
2081		pr_debug("%s: stem: %s, id: %d\n",
2082			 __func__, app->stem, app->id);
2083
2084		if (strcmp(app->stem, stem) != 0) {
2085			pr_debug("%s: stem comparison didn't pass %s\n",
2086				 __func__, app->stem);
2087			continue;
2088		}
2089
2090		if (of_match_node(matches, app->np)) {
2091			pr_debug("%s: Allocated ID %d\n", __func__, app->id);
2092
2093			if (app->id >= nbits) {
2094				pr_warn("%s: ID %d >= than bitmap field %d\n",
2095					__func__, app->id, nbits);
2096				ret = -EOVERFLOW;
2097			} else {
2098				set_bit(app->id, bitmap);
2099			}
2100		}
2101	}
2102	mutex_unlock(&of_mutex);
2103
2104	return ret;
2105}
2106EXPORT_SYMBOL_GPL(of_alias_get_alias_list);
2107
2108/**
2109 * of_alias_get_highest_id - Get highest alias id for the given stem
2110 * @stem:	Alias stem to be examined
2111 *
2112 * The function travels the lookup table to get the highest alias id for the
2113 * given alias stem.  It returns the alias id if found.
2114 */
2115int of_alias_get_highest_id(const char *stem)
2116{
2117	struct alias_prop *app;
2118	int id = -ENODEV;
2119
2120	mutex_lock(&of_mutex);
2121	list_for_each_entry(app, &aliases_lookup, link) {
2122		if (strcmp(app->stem, stem) != 0)
2123			continue;
2124
2125		if (app->id > id)
2126			id = app->id;
2127	}
2128	mutex_unlock(&of_mutex);
2129
2130	return id;
2131}
2132EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
2133
2134/**
2135 * of_console_check() - Test and setup console for DT setup
2136 * @dn: Pointer to device node
2137 * @name: Name to use for preferred console without index. ex. "ttyS"
2138 * @index: Index to use for preferred console.
2139 *
2140 * Check if the given device node matches the stdout-path property in the
2141 * /chosen node. If it does then register it as the preferred console.
2142 *
2143 * Return: TRUE if console successfully setup. Otherwise return FALSE.
2144 */
2145bool of_console_check(struct device_node *dn, char *name, int index)
2146{
2147	if (!dn || dn != of_stdout || console_set_on_cmdline)
2148		return false;
2149
2150	/*
2151	 * XXX: cast `options' to char pointer to suppress complication
2152	 * warnings: printk, UART and console drivers expect char pointer.
2153	 */
2154	return !add_preferred_console(name, index, (char *)of_stdout_options);
2155}
2156EXPORT_SYMBOL_GPL(of_console_check);
2157
2158/**
2159 * of_find_next_cache_node - Find a node's subsidiary cache
2160 * @np:	node of type "cpu" or "cache"
2161 *
2162 * Return: A node pointer with refcount incremented, use
2163 * of_node_put() on it when done.  Caller should hold a reference
2164 * to np.
2165 */
2166struct device_node *of_find_next_cache_node(const struct device_node *np)
2167{
2168	struct device_node *child, *cache_node;
2169
2170	cache_node = of_parse_phandle(np, "l2-cache", 0);
2171	if (!cache_node)
2172		cache_node = of_parse_phandle(np, "next-level-cache", 0);
2173
2174	if (cache_node)
2175		return cache_node;
2176
2177	/* OF on pmac has nodes instead of properties named "l2-cache"
2178	 * beneath CPU nodes.
2179	 */
2180	if (IS_ENABLED(CONFIG_PPC_PMAC) && of_node_is_type(np, "cpu"))
2181		for_each_child_of_node(np, child)
2182			if (of_node_is_type(child, "cache"))
2183				return child;
2184
2185	return NULL;
2186}
2187
2188/**
2189 * of_find_last_cache_level - Find the level at which the last cache is
2190 * 		present for the given logical cpu
2191 *
2192 * @cpu: cpu number(logical index) for which the last cache level is needed
2193 *
2194 * Return: The the level at which the last cache is present. It is exactly
2195 * same as  the total number of cache levels for the given logical cpu.
2196 */
2197int of_find_last_cache_level(unsigned int cpu)
2198{
2199	u32 cache_level = 0;
2200	struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
2201
2202	while (np) {
 
2203		prev = np;
2204		of_node_put(np);
2205		np = of_find_next_cache_node(np);
2206	}
2207
2208	of_property_read_u32(prev, "cache-level", &cache_level);
 
2209
2210	return cache_level;
2211}
2212
2213/**
2214 * of_map_id - Translate an ID through a downstream mapping.
2215 * @np: root complex device node.
2216 * @id: device ID to map.
2217 * @map_name: property name of the map to use.
2218 * @map_mask_name: optional property name of the mask to use.
2219 * @target: optional pointer to a target device node.
2220 * @id_out: optional pointer to receive the translated ID.
2221 *
2222 * Given a device ID, look up the appropriate implementation-defined
2223 * platform ID and/or the target device which receives transactions on that
2224 * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
2225 * @id_out may be NULL if only the other is required. If @target points to
2226 * a non-NULL device node pointer, only entries targeting that node will be
2227 * matched; if it points to a NULL value, it will receive the device node of
2228 * the first matching target phandle, with a reference held.
2229 *
2230 * Return: 0 on success or a standard error code on failure.
2231 */
2232int of_map_id(struct device_node *np, u32 id,
2233	       const char *map_name, const char *map_mask_name,
2234	       struct device_node **target, u32 *id_out)
2235{
2236	u32 map_mask, masked_id;
2237	int map_len;
2238	const __be32 *map = NULL;
2239
2240	if (!np || !map_name || (!target && !id_out))
2241		return -EINVAL;
2242
2243	map = of_get_property(np, map_name, &map_len);
2244	if (!map) {
2245		if (target)
2246			return -ENODEV;
2247		/* Otherwise, no map implies no translation */
2248		*id_out = id;
2249		return 0;
2250	}
2251
2252	if (!map_len || map_len % (4 * sizeof(*map))) {
2253		pr_err("%pOF: Error: Bad %s length: %d\n", np,
2254			map_name, map_len);
2255		return -EINVAL;
2256	}
2257
2258	/* The default is to select all bits. */
2259	map_mask = 0xffffffff;
2260
2261	/*
2262	 * Can be overridden by "{iommu,msi}-map-mask" property.
2263	 * If of_property_read_u32() fails, the default is used.
2264	 */
2265	if (map_mask_name)
2266		of_property_read_u32(np, map_mask_name, &map_mask);
2267
2268	masked_id = map_mask & id;
2269	for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
2270		struct device_node *phandle_node;
2271		u32 id_base = be32_to_cpup(map + 0);
2272		u32 phandle = be32_to_cpup(map + 1);
2273		u32 out_base = be32_to_cpup(map + 2);
2274		u32 id_len = be32_to_cpup(map + 3);
2275
2276		if (id_base & ~map_mask) {
2277			pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores id-base (0x%x)\n",
2278				np, map_name, map_name,
2279				map_mask, id_base);
2280			return -EFAULT;
2281		}
2282
2283		if (masked_id < id_base || masked_id >= id_base + id_len)
2284			continue;
2285
2286		phandle_node = of_find_node_by_phandle(phandle);
2287		if (!phandle_node)
2288			return -ENODEV;
2289
2290		if (target) {
2291			if (*target)
2292				of_node_put(phandle_node);
2293			else
2294				*target = phandle_node;
2295
2296			if (*target != phandle_node)
2297				continue;
2298		}
2299
2300		if (id_out)
2301			*id_out = masked_id - id_base + out_base;
2302
2303		pr_debug("%pOF: %s, using mask %08x, id-base: %08x, out-base: %08x, length: %08x, id: %08x -> %08x\n",
2304			np, map_name, map_mask, id_base, out_base,
2305			id_len, id, masked_id - id_base + out_base);
2306		return 0;
2307	}
2308
2309	pr_info("%pOF: no %s translation for id 0x%x on %pOF\n", np, map_name,
2310		id, target && *target ? *target : NULL);
2311
2312	/* Bypasses translation */
2313	if (id_out)
2314		*id_out = id;
2315	return 0;
2316}
2317EXPORT_SYMBOL_GPL(of_map_id);