1/*
   2 * Procedures for creating, accessing and interpreting the device tree.
   3 *
   4 * Paul Mackerras	August 1996.
   5 * Copyright (C) 1996-2005 Paul Mackerras.
   6 *
   7 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
   8 *    {engebret|bergner}@us.ibm.com
   9 *
  10 *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
  11 *
  12 *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
  13 *  Grant Likely.
  14 *
  15 *      This program is free software; you can redistribute it and/or
  16 *      modify it under the terms of the GNU General Public License
  17 *      as published by the Free Software Foundation; either version
  18 *      2 of the License, or (at your option) any later version.
  19 */
  20
  21#define pr_fmt(fmt)	"OF: " fmt
  22
  23#include <linux/console.h>
  24#include <linux/ctype.h>
  25#include <linux/cpu.h>
  26#include <linux/module.h>
  27#include <linux/of.h>
  28#include <linux/of_graph.h>
  29#include <linux/spinlock.h>
  30#include <linux/slab.h>
  31#include <linux/string.h>
  32#include <linux/proc_fs.h>
  33
  34#include "of_private.h"
  35
  36LIST_HEAD(aliases_lookup);
  37
  38struct device_node *of_root;
  39EXPORT_SYMBOL(of_root);
  40struct device_node *of_chosen;
  41struct device_node *of_aliases;
  42struct device_node *of_stdout;
  43static const char *of_stdout_options;
  44
  45struct kset *of_kset;
  46
  47/*
  48 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
  49 * This mutex must be held whenever modifications are being made to the
  50 * device tree. The of_{attach,detach}_node() and
  51 * of_{add,remove,update}_property() helpers make sure this happens.
  52 */
  53DEFINE_MUTEX(of_mutex);
  54
  55/* use when traversing tree through the child, sibling,
  56 * or parent members of struct device_node.
  57 */
  58DEFINE_RAW_SPINLOCK(devtree_lock);
  59
  60int of_n_addr_cells(struct device_node *np)
  61{
  62	const __be32 *ip;
  63
  64	do {
  65		if (np->parent)
  66			np = np->parent;
  67		ip = of_get_property(np, "#address-cells", NULL);
  68		if (ip)
  69			return be32_to_cpup(ip);
  70	} while (np->parent);
  71	/* No #address-cells property for the root node */
  72	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
  73}
  74EXPORT_SYMBOL(of_n_addr_cells);
  75
  76int of_n_size_cells(struct device_node *np)
  77{
  78	const __be32 *ip;
  79
  80	do {
  81		if (np->parent)
  82			np = np->parent;
  83		ip = of_get_property(np, "#size-cells", NULL);
  84		if (ip)
  85			return be32_to_cpup(ip);
  86	} while (np->parent);
  87	/* No #size-cells property for the root node */
  88	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
  89}
  90EXPORT_SYMBOL(of_n_size_cells);
  91
  92#ifdef CONFIG_NUMA
  93int __weak of_node_to_nid(struct device_node *np)
  94{
  95	return NUMA_NO_NODE;
  96}
  97#endif
  98
  99#ifndef CONFIG_OF_DYNAMIC
 100static void of_node_release(struct kobject *kobj)
 101{
 102	/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
 103}
 104#endif /* CONFIG_OF_DYNAMIC */
 105
 106struct kobj_type of_node_ktype = {
 107	.release = of_node_release,
 108};
 109
 110static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
 111				struct bin_attribute *bin_attr, char *buf,
 112				loff_t offset, size_t count)
 113{
 114	struct property *pp = container_of(bin_attr, struct property, attr);
 115	return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
 116}
 117
 118/* always return newly allocated name, caller must free after use */
 119static const char *safe_name(struct kobject *kobj, const char *orig_name)
 120{
 121	const char *name = orig_name;
 122	struct kernfs_node *kn;
 123	int i = 0;
 124
 125	/* don't be a hero. After 16 tries give up */
 126	while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
 127		sysfs_put(kn);
 128		if (name != orig_name)
 129			kfree(name);
 130		name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
 131	}
 132
 133	if (name == orig_name) {
 134		name = kstrdup(orig_name, GFP_KERNEL);
 135	} else {
 136		pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
 137			kobject_name(kobj), name);
 138	}
 139	return name;
 140}
 141
 142int __of_add_property_sysfs(struct device_node *np, struct property *pp)
 143{
 144	int rc;
 145
 146	/* Important: Don't leak passwords */
 147	bool secure = strncmp(pp->name, "security-", 9) == 0;
 148
 149	if (!IS_ENABLED(CONFIG_SYSFS))
 150		return 0;
 151
 152	if (!of_kset || !of_node_is_attached(np))
 153		return 0;
 154
 155	sysfs_bin_attr_init(&pp->attr);
 156	pp->attr.attr.name = safe_name(&np->kobj, pp->name);
 157	pp->attr.attr.mode = secure ? S_IRUSR : S_IRUGO;
 158	pp->attr.size = secure ? 0 : pp->length;
 159	pp->attr.read = of_node_property_read;
 160
 161	rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
 162	WARN(rc, "error adding attribute %s to node %s\n", pp->name, np->full_name);
 163	return rc;
 164}
 165
 166int __of_attach_node_sysfs(struct device_node *np)
 167{
 168	const char *name;
 169	struct kobject *parent;
 170	struct property *pp;
 171	int rc;
 172
 173	if (!IS_ENABLED(CONFIG_SYSFS))
 174		return 0;
 175
 176	if (!of_kset)
 177		return 0;
 178
 179	np->kobj.kset = of_kset;
 180	if (!np->parent) {
 181		/* Nodes without parents are new top level trees */
 182		name = safe_name(&of_kset->kobj, "base");
 183		parent = NULL;
 184	} else {
 185		name = safe_name(&np->parent->kobj, kbasename(np->full_name));
 186		parent = &np->parent->kobj;
 
 
 
 187	}
 188	if (!name)
 189		return -ENOMEM;
 190	rc = kobject_add(&np->kobj, parent, "%s", name);
 191	kfree(name);
 192	if (rc)
 193		return rc;
 194
 195	for_each_property_of_node(np, pp)
 196		__of_add_property_sysfs(np, pp);
 197
 198	return 0;
 199}
 200
 201void __init of_core_init(void)
 202{
 203	struct device_node *np;
 204
 205	/* Create the kset, and register existing nodes */
 206	mutex_lock(&of_mutex);
 207	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
 208	if (!of_kset) {
 209		mutex_unlock(&of_mutex);
 210		pr_err("failed to register existing nodes\n");
 211		return;
 212	}
 213	for_each_of_allnodes(np)
 214		__of_attach_node_sysfs(np);
 215	mutex_unlock(&of_mutex);
 216
 217	/* Symlink in /proc as required by userspace ABI */
 218	if (of_root)
 219		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
 220}
 221
 222static struct property *__of_find_property(const struct device_node *np,
 223					   const char *name, int *lenp)
 224{
 225	struct property *pp;
 226
 227	if (!np)
 228		return NULL;
 229
 230	for (pp = np->properties; pp; pp = pp->next) {
 231		if (of_prop_cmp(pp->name, name) == 0) {
 232			if (lenp)
 233				*lenp = pp->length;
 234			break;
 235		}
 236	}
 237
 238	return pp;
 239}
 240
 241struct property *of_find_property(const struct device_node *np,
 242				  const char *name,
 243				  int *lenp)
 244{
 245	struct property *pp;
 246	unsigned long flags;
 247
 248	raw_spin_lock_irqsave(&devtree_lock, flags);
 249	pp = __of_find_property(np, name, lenp);
 250	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 251
 252	return pp;
 253}
 254EXPORT_SYMBOL(of_find_property);
 255
 256struct device_node *__of_find_all_nodes(struct device_node *prev)
 257{
 258	struct device_node *np;
 259	if (!prev) {
 260		np = of_root;
 261	} else if (prev->child) {
 262		np = prev->child;
 263	} else {
 264		/* Walk back up looking for a sibling, or the end of the structure */
 265		np = prev;
 266		while (np->parent && !np->sibling)
 267			np = np->parent;
 268		np = np->sibling; /* Might be null at the end of the tree */
 269	}
 270	return np;
 271}
 272
 273/**
 274 * of_find_all_nodes - Get next node in global list
 275 * @prev:	Previous node or NULL to start iteration
 276 *		of_node_put() will be called on it
 277 *
 278 * Returns a node pointer with refcount incremented, use
 279 * of_node_put() on it when done.
 280 */
 281struct device_node *of_find_all_nodes(struct device_node *prev)
 282{
 283	struct device_node *np;
 284	unsigned long flags;
 285
 286	raw_spin_lock_irqsave(&devtree_lock, flags);
 287	np = __of_find_all_nodes(prev);
 288	of_node_get(np);
 289	of_node_put(prev);
 290	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 291	return np;
 292}
 293EXPORT_SYMBOL(of_find_all_nodes);
 294
 295/*
 296 * Find a property with a given name for a given node
 297 * and return the value.
 298 */
 299const void *__of_get_property(const struct device_node *np,
 300			      const char *name, int *lenp)
 301{
 302	struct property *pp = __of_find_property(np, name, lenp);
 303
 304	return pp ? pp->value : NULL;
 305}
 306
 307/*
 308 * Find a property with a given name for a given node
 309 * and return the value.
 310 */
 311const void *of_get_property(const struct device_node *np, const char *name,
 312			    int *lenp)
 313{
 314	struct property *pp = of_find_property(np, name, lenp);
 315
 316	return pp ? pp->value : NULL;
 317}
 318EXPORT_SYMBOL(of_get_property);
 319
 320/*
 321 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
 322 *
 323 * @cpu: logical cpu index of a core/thread
 324 * @phys_id: physical identifier of a core/thread
 325 *
 326 * CPU logical to physical index mapping is architecture specific.
 327 * However this __weak function provides a default match of physical
 328 * id to logical cpu index. phys_id provided here is usually values read
 329 * from the device tree which must match the hardware internal registers.
 330 *
 331 * Returns true if the physical identifier and the logical cpu index
 332 * correspond to the same core/thread, false otherwise.
 333 */
 334bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
 335{
 336	return (u32)phys_id == cpu;
 337}
 338
 339/**
 340 * Checks if the given "prop_name" property holds the physical id of the
 341 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
 342 * NULL, local thread number within the core is returned in it.
 343 */
 344static bool __of_find_n_match_cpu_property(struct device_node *cpun,
 345			const char *prop_name, int cpu, unsigned int *thread)
 346{
 347	const __be32 *cell;
 348	int ac, prop_len, tid;
 349	u64 hwid;
 350
 351	ac = of_n_addr_cells(cpun);
 352	cell = of_get_property(cpun, prop_name, &prop_len);
 353	if (!cell || !ac)
 354		return false;
 355	prop_len /= sizeof(*cell) * ac;
 356	for (tid = 0; tid < prop_len; tid++) {
 357		hwid = of_read_number(cell, ac);
 358		if (arch_match_cpu_phys_id(cpu, hwid)) {
 359			if (thread)
 360				*thread = tid;
 361			return true;
 362		}
 363		cell += ac;
 364	}
 365	return false;
 366}
 367
 368/*
 369 * arch_find_n_match_cpu_physical_id - See if the given device node is
 370 * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
 371 * else false.  If 'thread' is non-NULL, the local thread number within the
 372 * core is returned in it.
 373 */
 374bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
 375					      int cpu, unsigned int *thread)
 376{
 377	/* Check for non-standard "ibm,ppc-interrupt-server#s" property
 378	 * for thread ids on PowerPC. If it doesn't exist fallback to
 379	 * standard "reg" property.
 380	 */
 381	if (IS_ENABLED(CONFIG_PPC) &&
 382	    __of_find_n_match_cpu_property(cpun,
 383					   "ibm,ppc-interrupt-server#s",
 384					   cpu, thread))
 385		return true;
 386
 387	return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
 388}
 389
 390/**
 391 * of_get_cpu_node - Get device node associated with the given logical CPU
 392 *
 393 * @cpu: CPU number(logical index) for which device node is required
 394 * @thread: if not NULL, local thread number within the physical core is
 395 *          returned
 396 *
 397 * The main purpose of this function is to retrieve the device node for the
 398 * given logical CPU index. It should be used to initialize the of_node in
 399 * cpu device. Once of_node in cpu device is populated, all the further
 400 * references can use that instead.
 401 *
 402 * CPU logical to physical index mapping is architecture specific and is built
 403 * before booting secondary cores. This function uses arch_match_cpu_phys_id
 404 * which can be overridden by architecture specific implementation.
 405 *
 406 * Returns a node pointer for the logical cpu with refcount incremented, use
 407 * of_node_put() on it when done. Returns NULL if not found.
 408 */
 409struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
 410{
 411	struct device_node *cpun;
 412
 413	for_each_node_by_type(cpun, "cpu") {
 414		if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
 415			return cpun;
 416	}
 417	return NULL;
 418}
 419EXPORT_SYMBOL(of_get_cpu_node);
 420
 421/**
 422 * __of_device_is_compatible() - Check if the node matches given constraints
 423 * @device: pointer to node
 424 * @compat: required compatible string, NULL or "" for any match
 425 * @type: required device_type value, NULL or "" for any match
 426 * @name: required node name, NULL or "" for any match
 427 *
 428 * Checks if the given @compat, @type and @name strings match the
 429 * properties of the given @device. A constraints can be skipped by
 430 * passing NULL or an empty string as the constraint.
 431 *
 432 * Returns 0 for no match, and a positive integer on match. The return
 433 * value is a relative score with larger values indicating better
 434 * matches. The score is weighted for the most specific compatible value
 435 * to get the highest score. Matching type is next, followed by matching
 436 * name. Practically speaking, this results in the following priority
 437 * order for matches:
 438 *
 439 * 1. specific compatible && type && name
 440 * 2. specific compatible && type
 441 * 3. specific compatible && name
 442 * 4. specific compatible
 443 * 5. general compatible && type && name
 444 * 6. general compatible && type
 445 * 7. general compatible && name
 446 * 8. general compatible
 447 * 9. type && name
 448 * 10. type
 449 * 11. name
 450 */
 451static int __of_device_is_compatible(const struct device_node *device,
 452				     const char *compat, const char *type, const char *name)
 453{
 454	struct property *prop;
 455	const char *cp;
 456	int index = 0, score = 0;
 457
 458	/* Compatible match has highest priority */
 459	if (compat && compat[0]) {
 460		prop = __of_find_property(device, "compatible", NULL);
 461		for (cp = of_prop_next_string(prop, NULL); cp;
 462		     cp = of_prop_next_string(prop, cp), index++) {
 463			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
 464				score = INT_MAX/2 - (index << 2);
 465				break;
 466			}
 467		}
 468		if (!score)
 469			return 0;
 470	}
 471
 472	/* Matching type is better than matching name */
 473	if (type && type[0]) {
 474		if (!device->type || of_node_cmp(type, device->type))
 475			return 0;
 476		score += 2;
 477	}
 478
 479	/* Matching name is a bit better than not */
 480	if (name && name[0]) {
 481		if (!device->name || of_node_cmp(name, device->name))
 482			return 0;
 483		score++;
 484	}
 485
 486	return score;
 487}
 488
 489/** Checks if the given "compat" string matches one of the strings in
 490 * the device's "compatible" property
 491 */
 492int of_device_is_compatible(const struct device_node *device,
 493		const char *compat)
 494{
 495	unsigned long flags;
 496	int res;
 497
 498	raw_spin_lock_irqsave(&devtree_lock, flags);
 499	res = __of_device_is_compatible(device, compat, NULL, NULL);
 500	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 501	return res;
 502}
 503EXPORT_SYMBOL(of_device_is_compatible);
 504
 505/** Checks if the device is compatible with any of the entries in
 506 *  a NULL terminated array of strings. Returns the best match
 507 *  score or 0.
 508 */
 509int of_device_compatible_match(struct device_node *device,
 510			       const char *const *compat)
 511{
 512	unsigned int tmp, score = 0;
 513
 514	if (!compat)
 515		return 0;
 516
 517	while (*compat) {
 518		tmp = of_device_is_compatible(device, *compat);
 519		if (tmp > score)
 520			score = tmp;
 521		compat++;
 522	}
 523
 524	return score;
 525}
 526
 527/**
 528 * of_machine_is_compatible - Test root of device tree for a given compatible value
 529 * @compat: compatible string to look for in root node's compatible property.
 530 *
 531 * Returns a positive integer if the root node has the given value in its
 532 * compatible property.
 533 */
 534int of_machine_is_compatible(const char *compat)
 535{
 536	struct device_node *root;
 537	int rc = 0;
 538
 539	root = of_find_node_by_path("/");
 540	if (root) {
 541		rc = of_device_is_compatible(root, compat);
 542		of_node_put(root);
 543	}
 544	return rc;
 545}
 546EXPORT_SYMBOL(of_machine_is_compatible);
 547
 548/**
 549 *  __of_device_is_available - check if a device is available for use
 550 *
 551 *  @device: Node to check for availability, with locks already held
 552 *
 553 *  Returns true if the status property is absent or set to "okay" or "ok",
 554 *  false otherwise
 555 */
 556static bool __of_device_is_available(const struct device_node *device)
 557{
 558	const char *status;
 559	int statlen;
 560
 561	if (!device)
 562		return false;
 563
 564	status = __of_get_property(device, "status", &statlen);
 565	if (status == NULL)
 566		return true;
 567
 568	if (statlen > 0) {
 569		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
 570			return true;
 571	}
 572
 573	return false;
 574}
 575
 576/**
 577 *  of_device_is_available - check if a device is available for use
 578 *
 579 *  @device: Node to check for availability
 580 *
 581 *  Returns true if the status property is absent or set to "okay" or "ok",
 582 *  false otherwise
 583 */
 584bool of_device_is_available(const struct device_node *device)
 585{
 586	unsigned long flags;
 587	bool res;
 588
 589	raw_spin_lock_irqsave(&devtree_lock, flags);
 590	res = __of_device_is_available(device);
 591	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 592	return res;
 593
 594}
 595EXPORT_SYMBOL(of_device_is_available);
 596
 597/**
 598 *  of_device_is_big_endian - check if a device has BE registers
 599 *
 600 *  @device: Node to check for endianness
 601 *
 602 *  Returns true if the device has a "big-endian" property, or if the kernel
 603 *  was compiled for BE *and* the device has a "native-endian" property.
 604 *  Returns false otherwise.
 605 *
 606 *  Callers would nominally use ioread32be/iowrite32be if
 607 *  of_device_is_big_endian() == true, or readl/writel otherwise.
 608 */
 609bool of_device_is_big_endian(const struct device_node *device)
 610{
 611	if (of_property_read_bool(device, "big-endian"))
 612		return true;
 613	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
 614	    of_property_read_bool(device, "native-endian"))
 615		return true;
 616	return false;
 617}
 618EXPORT_SYMBOL(of_device_is_big_endian);
 619
 620/**
 621 *	of_get_parent - Get a node's parent if any
 622 *	@node:	Node to get parent
 623 *
 624 *	Returns a node pointer with refcount incremented, use
 625 *	of_node_put() on it when done.
 626 */
 627struct device_node *of_get_parent(const struct device_node *node)
 628{
 629	struct device_node *np;
 630	unsigned long flags;
 631
 632	if (!node)
 633		return NULL;
 634
 635	raw_spin_lock_irqsave(&devtree_lock, flags);
 636	np = of_node_get(node->parent);
 637	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 638	return np;
 639}
 640EXPORT_SYMBOL(of_get_parent);
 641
 642/**
 643 *	of_get_next_parent - Iterate to a node's parent
 644 *	@node:	Node to get parent of
 645 *
 646 *	This is like of_get_parent() except that it drops the
 647 *	refcount on the passed node, making it suitable for iterating
 648 *	through a node's parents.
 649 *
 650 *	Returns a node pointer with refcount incremented, use
 651 *	of_node_put() on it when done.
 652 */
 653struct device_node *of_get_next_parent(struct device_node *node)
 654{
 655	struct device_node *parent;
 656	unsigned long flags;
 657
 658	if (!node)
 659		return NULL;
 660
 661	raw_spin_lock_irqsave(&devtree_lock, flags);
 662	parent = of_node_get(node->parent);
 663	of_node_put(node);
 664	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 665	return parent;
 666}
 667EXPORT_SYMBOL(of_get_next_parent);
 668
 669static struct device_node *__of_get_next_child(const struct device_node *node,
 670						struct device_node *prev)
 671{
 672	struct device_node *next;
 673
 674	if (!node)
 675		return NULL;
 676
 677	next = prev ? prev->sibling : node->child;
 678	for (; next; next = next->sibling)
 679		if (of_node_get(next))
 680			break;
 681	of_node_put(prev);
 682	return next;
 683}
 684#define __for_each_child_of_node(parent, child) \
 685	for (child = __of_get_next_child(parent, NULL); child != NULL; \
 686	     child = __of_get_next_child(parent, child))
 687
 688/**
 689 *	of_get_next_child - Iterate a node childs
 690 *	@node:	parent node
 691 *	@prev:	previous child of the parent node, or NULL to get first
 692 *
 693 *	Returns a node pointer with refcount incremented, use of_node_put() on
 694 *	it when done. Returns NULL when prev is the last child. Decrements the
 695 *	refcount of prev.
 696 */
 697struct device_node *of_get_next_child(const struct device_node *node,
 698	struct device_node *prev)
 699{
 700	struct device_node *next;
 701	unsigned long flags;
 702
 703	raw_spin_lock_irqsave(&devtree_lock, flags);
 704	next = __of_get_next_child(node, prev);
 705	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 706	return next;
 707}
 708EXPORT_SYMBOL(of_get_next_child);
 709
 710/**
 711 *	of_get_next_available_child - Find the next available child node
 712 *	@node:	parent node
 713 *	@prev:	previous child of the parent node, or NULL to get first
 714 *
 715 *      This function is like of_get_next_child(), except that it
 716 *      automatically skips any disabled nodes (i.e. status = "disabled").
 717 */
 718struct device_node *of_get_next_available_child(const struct device_node *node,
 719	struct device_node *prev)
 720{
 721	struct device_node *next;
 722	unsigned long flags;
 723
 724	if (!node)
 725		return NULL;
 726
 727	raw_spin_lock_irqsave(&devtree_lock, flags);
 728	next = prev ? prev->sibling : node->child;
 729	for (; next; next = next->sibling) {
 730		if (!__of_device_is_available(next))
 731			continue;
 732		if (of_node_get(next))
 733			break;
 734	}
 735	of_node_put(prev);
 736	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 737	return next;
 738}
 739EXPORT_SYMBOL(of_get_next_available_child);
 740
 741/**
 742 *	of_get_child_by_name - Find the child node by name for a given parent
 743 *	@node:	parent node
 744 *	@name:	child name to look for.
 745 *
 746 *      This function looks for child node for given matching name
 747 *
 748 *	Returns a node pointer if found, with refcount incremented, use
 749 *	of_node_put() on it when done.
 750 *	Returns NULL if node is not found.
 751 */
 752struct device_node *of_get_child_by_name(const struct device_node *node,
 753				const char *name)
 754{
 755	struct device_node *child;
 756
 757	for_each_child_of_node(node, child)
 758		if (child->name && (of_node_cmp(child->name, name) == 0))
 759			break;
 760	return child;
 761}
 762EXPORT_SYMBOL(of_get_child_by_name);
 763
 764static struct device_node *__of_find_node_by_path(struct device_node *parent,
 765						const char *path)
 766{
 767	struct device_node *child;
 768	int len;
 769
 770	len = strcspn(path, "/:");
 771	if (!len)
 772		return NULL;
 773
 774	__for_each_child_of_node(parent, child) {
 775		const char *name = strrchr(child->full_name, '/');
 776		if (WARN(!name, "malformed device_node %s\n", child->full_name))
 777			continue;
 778		name++;
 779		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
 780			return child;
 781	}
 782	return NULL;
 783}
 784
 785/**
 786 *	of_find_node_opts_by_path - Find a node matching a full OF path
 787 *	@path: Either the full path to match, or if the path does not
 788 *	       start with '/', the name of a property of the /aliases
 789 *	       node (an alias).  In the case of an alias, the node
 790 *	       matching the alias' value will be returned.
 791 *	@opts: Address of a pointer into which to store the start of
 792 *	       an options string appended to the end of the path with
 793 *	       a ':' separator.
 794 *
 795 *	Valid paths:
 796 *		/foo/bar	Full path
 797 *		foo		Valid alias
 798 *		foo/bar		Valid alias + relative path
 799 *
 800 *	Returns a node pointer with refcount incremented, use
 801 *	of_node_put() on it when done.
 802 */
 803struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
 804{
 805	struct device_node *np = NULL;
 806	struct property *pp;
 807	unsigned long flags;
 808	const char *separator = strchr(path, ':');
 809
 810	if (opts)
 811		*opts = separator ? separator + 1 : NULL;
 812
 813	if (strcmp(path, "/") == 0)
 814		return of_node_get(of_root);
 815
 816	/* The path could begin with an alias */
 817	if (*path != '/') {
 818		int len;
 819		const char *p = separator;
 820
 821		if (!p)
 822			p = strchrnul(path, '/');
 823		len = p - path;
 824
 825		/* of_aliases must not be NULL */
 826		if (!of_aliases)
 827			return NULL;
 828
 829		for_each_property_of_node(of_aliases, pp) {
 830			if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
 831				np = of_find_node_by_path(pp->value);
 832				break;
 833			}
 834		}
 835		if (!np)
 836			return NULL;
 837		path = p;
 838	}
 839
 840	/* Step down the tree matching path components */
 841	raw_spin_lock_irqsave(&devtree_lock, flags);
 842	if (!np)
 843		np = of_node_get(of_root);
 844	while (np && *path == '/') {
 845		path++; /* Increment past '/' delimiter */
 846		np = __of_find_node_by_path(np, path);
 847		path = strchrnul(path, '/');
 848		if (separator && separator < path)
 849			break;
 850	}
 851	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 852	return np;
 853}
 854EXPORT_SYMBOL(of_find_node_opts_by_path);
 855
 856/**
 857 *	of_find_node_by_name - Find a node by its "name" property
 858 *	@from:	The node to start searching from or NULL, the node
 859 *		you pass will not be searched, only the next one
 860 *		will; typically, you pass what the previous call
 861 *		returned. of_node_put() will be called on it
 862 *	@name:	The name string to match against
 863 *
 864 *	Returns a node pointer with refcount incremented, use
 865 *	of_node_put() on it when done.
 866 */
 867struct device_node *of_find_node_by_name(struct device_node *from,
 868	const char *name)
 869{
 870	struct device_node *np;
 871	unsigned long flags;
 872
 873	raw_spin_lock_irqsave(&devtree_lock, flags);
 874	for_each_of_allnodes_from(from, np)
 875		if (np->name && (of_node_cmp(np->name, name) == 0)
 876		    && of_node_get(np))
 877			break;
 878	of_node_put(from);
 879	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 880	return np;
 881}
 882EXPORT_SYMBOL(of_find_node_by_name);
 883
 884/**
 885 *	of_find_node_by_type - Find a node by its "device_type" property
 886 *	@from:	The node to start searching from, or NULL to start searching
 887 *		the entire device tree. The node you pass will not be
 888 *		searched, only the next one will; typically, you pass
 889 *		what the previous call returned. of_node_put() will be
 890 *		called on from for you.
 891 *	@type:	The type string to match against
 892 *
 893 *	Returns a node pointer with refcount incremented, use
 894 *	of_node_put() on it when done.
 895 */
 896struct device_node *of_find_node_by_type(struct device_node *from,
 897	const char *type)
 898{
 899	struct device_node *np;
 900	unsigned long flags;
 901
 902	raw_spin_lock_irqsave(&devtree_lock, flags);
 903	for_each_of_allnodes_from(from, np)
 904		if (np->type && (of_node_cmp(np->type, type) == 0)
 905		    && of_node_get(np))
 906			break;
 907	of_node_put(from);
 908	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 909	return np;
 910}
 911EXPORT_SYMBOL(of_find_node_by_type);
 912
 913/**
 914 *	of_find_compatible_node - Find a node based on type and one of the
 915 *                                tokens in its "compatible" property
 916 *	@from:		The node to start searching from or NULL, the node
 917 *			you pass will not be searched, only the next one
 918 *			will; typically, you pass what the previous call
 919 *			returned. of_node_put() will be called on it
 920 *	@type:		The type string to match "device_type" or NULL to ignore
 921 *	@compatible:	The string to match to one of the tokens in the device
 922 *			"compatible" list.
 923 *
 924 *	Returns a node pointer with refcount incremented, use
 925 *	of_node_put() on it when done.
 926 */
 927struct device_node *of_find_compatible_node(struct device_node *from,
 928	const char *type, const char *compatible)
 929{
 930	struct device_node *np;
 931	unsigned long flags;
 932
 933	raw_spin_lock_irqsave(&devtree_lock, flags);
 934	for_each_of_allnodes_from(from, np)
 935		if (__of_device_is_compatible(np, compatible, type, NULL) &&
 936		    of_node_get(np))
 937			break;
 938	of_node_put(from);
 939	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 940	return np;
 941}
 942EXPORT_SYMBOL(of_find_compatible_node);
 943
 944/**
 945 *	of_find_node_with_property - Find a node which has a property with
 946 *                                   the given name.
 947 *	@from:		The node to start searching from or NULL, the node
 948 *			you pass will not be searched, only the next one
 949 *			will; typically, you pass what the previous call
 950 *			returned. of_node_put() will be called on it
 951 *	@prop_name:	The name of the property to look for.
 952 *
 953 *	Returns a node pointer with refcount incremented, use
 954 *	of_node_put() on it when done.
 955 */
 956struct device_node *of_find_node_with_property(struct device_node *from,
 957	const char *prop_name)
 958{
 959	struct device_node *np;
 960	struct property *pp;
 961	unsigned long flags;
 962
 963	raw_spin_lock_irqsave(&devtree_lock, flags);
 964	for_each_of_allnodes_from(from, np) {
 965		for (pp = np->properties; pp; pp = pp->next) {
 966			if (of_prop_cmp(pp->name, prop_name) == 0) {
 967				of_node_get(np);
 968				goto out;
 969			}
 970		}
 971	}
 972out:
 973	of_node_put(from);
 974	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 975	return np;
 976}
 977EXPORT_SYMBOL(of_find_node_with_property);
 978
 979static
 980const struct of_device_id *__of_match_node(const struct of_device_id *matches,
 981					   const struct device_node *node)
 982{
 983	const struct of_device_id *best_match = NULL;
 984	int score, best_score = 0;
 985
 986	if (!matches)
 987		return NULL;
 988
 989	for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
 990		score = __of_device_is_compatible(node, matches->compatible,
 991						  matches->type, matches->name);
 992		if (score > best_score) {
 993			best_match = matches;
 994			best_score = score;
 995		}
 996	}
 997
 998	return best_match;
 999}
1000
1001/**
1002 * of_match_node - Tell if a device_node has a matching of_match structure
1003 *	@matches:	array of of device match structures to search in
1004 *	@node:		the of device structure to match against
1005 *
1006 *	Low level utility function used by device matching.
1007 */
1008const struct of_device_id *of_match_node(const struct of_device_id *matches,
1009					 const struct device_node *node)
1010{
1011	const struct of_device_id *match;
1012	unsigned long flags;
1013
1014	raw_spin_lock_irqsave(&devtree_lock, flags);
1015	match = __of_match_node(matches, node);
1016	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1017	return match;
1018}
1019EXPORT_SYMBOL(of_match_node);
1020
1021/**
1022 *	of_find_matching_node_and_match - Find a node based on an of_device_id
1023 *					  match table.
1024 *	@from:		The node to start searching from or NULL, the node
1025 *			you pass will not be searched, only the next one
1026 *			will; typically, you pass what the previous call
1027 *			returned. of_node_put() will be called on it
1028 *	@matches:	array of of device match structures to search in
1029 *	@match		Updated to point at the matches entry which matched
1030 *
1031 *	Returns a node pointer with refcount incremented, use
1032 *	of_node_put() on it when done.
1033 */
1034struct device_node *of_find_matching_node_and_match(struct device_node *from,
1035					const struct of_device_id *matches,
1036					const struct of_device_id **match)
1037{
1038	struct device_node *np;
1039	const struct of_device_id *m;
1040	unsigned long flags;
1041
1042	if (match)
1043		*match = NULL;
1044
1045	raw_spin_lock_irqsave(&devtree_lock, flags);
1046	for_each_of_allnodes_from(from, np) {
1047		m = __of_match_node(matches, np);
1048		if (m && of_node_get(np)) {
1049			if (match)
1050				*match = m;
1051			break;
1052		}
1053	}
1054	of_node_put(from);
1055	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1056	return np;
1057}
1058EXPORT_SYMBOL(of_find_matching_node_and_match);
1059
1060/**
1061 * of_modalias_node - Lookup appropriate modalias for a device node
1062 * @node:	pointer to a device tree node
1063 * @modalias:	Pointer to buffer that modalias value will be copied into
1064 * @len:	Length of modalias value
1065 *
1066 * Based on the value of the compatible property, this routine will attempt
1067 * to choose an appropriate modalias value for a particular device tree node.
1068 * It does this by stripping the manufacturer prefix (as delimited by a ',')
1069 * from the first entry in the compatible list property.
1070 *
1071 * This routine returns 0 on success, <0 on failure.
1072 */
1073int of_modalias_node(struct device_node *node, char *modalias, int len)
1074{
1075	const char *compatible, *p;
1076	int cplen;
1077
1078	compatible = of_get_property(node, "compatible", &cplen);
1079	if (!compatible || strlen(compatible) > cplen)
1080		return -ENODEV;
1081	p = strchr(compatible, ',');
1082	strlcpy(modalias, p ? p + 1 : compatible, len);
1083	return 0;
1084}
1085EXPORT_SYMBOL_GPL(of_modalias_node);
1086
1087/**
1088 * of_find_node_by_phandle - Find a node given a phandle
1089 * @handle:	phandle of the node to find
1090 *
1091 * Returns a node pointer with refcount incremented, use
1092 * of_node_put() on it when done.
1093 */
1094struct device_node *of_find_node_by_phandle(phandle handle)
1095{
1096	struct device_node *np;
1097	unsigned long flags;
1098
1099	if (!handle)
1100		return NULL;
1101
1102	raw_spin_lock_irqsave(&devtree_lock, flags);
1103	for_each_of_allnodes(np)
1104		if (np->phandle == handle)
1105			break;
1106	of_node_get(np);
1107	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1108	return np;
1109}
1110EXPORT_SYMBOL(of_find_node_by_phandle);
1111
1112/**
1113 * of_property_count_elems_of_size - Count the number of elements in a property
1114 *
1115 * @np:		device node from which the property value is to be read.
1116 * @propname:	name of the property to be searched.
1117 * @elem_size:	size of the individual element
1118 *
1119 * Search for a property in a device node and count the number of elements of
1120 * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
1121 * property does not exist or its length does not match a multiple of elem_size
1122 * and -ENODATA if the property does not have a value.
1123 */
1124int of_property_count_elems_of_size(const struct device_node *np,
1125				const char *propname, int elem_size)
1126{
1127	struct property *prop = of_find_property(np, propname, NULL);
1128
1129	if (!prop)
1130		return -EINVAL;
1131	if (!prop->value)
1132		return -ENODATA;
1133
1134	if (prop->length % elem_size != 0) {
1135		pr_err("size of %s in node %s is not a multiple of %d\n",
1136		       propname, np->full_name, elem_size);
1137		return -EINVAL;
1138	}
1139
1140	return prop->length / elem_size;
1141}
1142EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
1143
1144/**
1145 * of_find_property_value_of_size
1146 *
1147 * @np:		device node from which the property value is to be read.
1148 * @propname:	name of the property to be searched.
1149 * @min:	minimum allowed length of property value
1150 * @max:	maximum allowed length of property value (0 means unlimited)
1151 * @len:	if !=NULL, actual length is written to here
1152 *
1153 * Search for a property in a device node and valid the requested size.
1154 * Returns the property value on success, -EINVAL if the property does not
1155 *  exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
1156 * property data is too small or too large.
1157 *
1158 */
1159static void *of_find_property_value_of_size(const struct device_node *np,
1160			const char *propname, u32 min, u32 max, size_t *len)
1161{
1162	struct property *prop = of_find_property(np, propname, NULL);
1163
1164	if (!prop)
1165		return ERR_PTR(-EINVAL);
1166	if (!prop->value)
1167		return ERR_PTR(-ENODATA);
1168	if (prop->length < min)
1169		return ERR_PTR(-EOVERFLOW);
1170	if (max && prop->length > max)
1171		return ERR_PTR(-EOVERFLOW);
1172
1173	if (len)
1174		*len = prop->length;
1175
1176	return prop->value;
1177}
1178
1179/**
1180 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
1181 *
1182 * @np:		device node from which the property value is to be read.
1183 * @propname:	name of the property to be searched.
1184 * @index:	index of the u32 in the list of values
1185 * @out_value:	pointer to return value, modified only if no error.
1186 *
1187 * Search for a property in a device node and read nth 32-bit value from
1188 * it. Returns 0 on success, -EINVAL if the property does not exist,
1189 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1190 * property data isn't large enough.
1191 *
1192 * The out_value is modified only if a valid u32 value can be decoded.
1193 */
1194int of_property_read_u32_index(const struct device_node *np,
1195				       const char *propname,
1196				       u32 index, u32 *out_value)
1197{
1198	const u32 *val = of_find_property_value_of_size(np, propname,
1199					((index + 1) * sizeof(*out_value)),
1200					0,
1201					NULL);
1202
1203	if (IS_ERR(val))
1204		return PTR_ERR(val);
1205
1206	*out_value = be32_to_cpup(((__be32 *)val) + index);
1207	return 0;
1208}
1209EXPORT_SYMBOL_GPL(of_property_read_u32_index);
1210
1211/**
1212 * of_property_read_variable_u8_array - Find and read an array of u8 from a
1213 * property, with bounds on the minimum and maximum array size.
1214 *
1215 * @np:		device node from which the property value is to be read.
1216 * @propname:	name of the property to be searched.
1217 * @out_values:	pointer to return value, modified only if return value is 0.
1218 * @sz_min:	minimum number of array elements to read
1219 * @sz_max:	maximum number of array elements to read, if zero there is no
1220 *		upper limit on the number of elements in the dts entry but only
1221 *		sz_min will be read.
1222 *
1223 * Search for a property in a device node and read 8-bit value(s) from
1224 * it. Returns number of elements read on success, -EINVAL if the property
1225 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
1226 * if the property data is smaller than sz_min or longer than sz_max.
1227 *
1228 * dts entry of array should be like:
1229 *	property = /bits/ 8 <0x50 0x60 0x70>;
1230 *
1231 * The out_values is modified only if a valid u8 value can be decoded.
1232 */
1233int of_property_read_variable_u8_array(const struct device_node *np,
1234					const char *propname, u8 *out_values,
1235					size_t sz_min, size_t sz_max)
1236{
1237	size_t sz, count;
1238	const u8 *val = of_find_property_value_of_size(np, propname,
1239						(sz_min * sizeof(*out_values)),
1240						(sz_max * sizeof(*out_values)),
1241						&sz);
1242
1243	if (IS_ERR(val))
1244		return PTR_ERR(val);
1245
1246	if (!sz_max)
1247		sz = sz_min;
1248	else
1249		sz /= sizeof(*out_values);
1250
1251	count = sz;
1252	while (count--)
1253		*out_values++ = *val++;
1254
1255	return sz;
1256}
1257EXPORT_SYMBOL_GPL(of_property_read_variable_u8_array);
1258
1259/**
1260 * of_property_read_variable_u16_array - Find and read an array of u16 from a
1261 * property, with bounds on the minimum and maximum array size.
1262 *
1263 * @np:		device node from which the property value is to be read.
1264 * @propname:	name of the property to be searched.
1265 * @out_values:	pointer to return value, modified only if return value is 0.
1266 * @sz_min:	minimum number of array elements to read
1267 * @sz_max:	maximum number of array elements to read, if zero there is no
1268 *		upper limit on the number of elements in the dts entry but only
1269 *		sz_min will be read.
1270 *
1271 * Search for a property in a device node and read 16-bit value(s) from
1272 * it. Returns number of elements read on success, -EINVAL if the property
1273 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
1274 * if the property data is smaller than sz_min or longer than sz_max.
1275 *
1276 * dts entry of array should be like:
1277 *	property = /bits/ 16 <0x5000 0x6000 0x7000>;
1278 *
1279 * The out_values is modified only if a valid u16 value can be decoded.
1280 */
1281int of_property_read_variable_u16_array(const struct device_node *np,
1282					const char *propname, u16 *out_values,
1283					size_t sz_min, size_t sz_max)
1284{
1285	size_t sz, count;
1286	const __be16 *val = of_find_property_value_of_size(np, propname,
1287						(sz_min * sizeof(*out_values)),
1288						(sz_max * sizeof(*out_values)),
1289						&sz);
1290
1291	if (IS_ERR(val))
1292		return PTR_ERR(val);
1293
1294	if (!sz_max)
1295		sz = sz_min;
1296	else
1297		sz /= sizeof(*out_values);
1298
1299	count = sz;
1300	while (count--)
1301		*out_values++ = be16_to_cpup(val++);
1302
1303	return sz;
1304}
1305EXPORT_SYMBOL_GPL(of_property_read_variable_u16_array);
1306
1307/**
1308 * of_property_read_variable_u32_array - Find and read an array of 32 bit
1309 * integers from a property, with bounds on the minimum and maximum array size.
1310 *
1311 * @np:		device node from which the property value is to be read.
1312 * @propname:	name of the property to be searched.
1313 * @out_values:	pointer to return value, modified only if return value is 0.
1314 * @sz_min:	minimum number of array elements to read
1315 * @sz_max:	maximum number of array elements to read, if zero there is no
1316 *		upper limit on the number of elements in the dts entry but only
1317 *		sz_min will be read.
1318 *
1319 * Search for a property in a device node and read 32-bit value(s) from
1320 * it. Returns number of elements read on success, -EINVAL if the property
1321 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
1322 * if the property data is smaller than sz_min or longer than sz_max.
1323 *
1324 * The out_values is modified only if a valid u32 value can be decoded.
1325 */
1326int of_property_read_variable_u32_array(const struct device_node *np,
1327			       const char *propname, u32 *out_values,
1328			       size_t sz_min, size_t sz_max)
1329{
1330	size_t sz, count;
1331	const __be32 *val = of_find_property_value_of_size(np, propname,
1332						(sz_min * sizeof(*out_values)),
1333						(sz_max * sizeof(*out_values)),
1334						&sz);
1335
1336	if (IS_ERR(val))
1337		return PTR_ERR(val);
1338
1339	if (!sz_max)
1340		sz = sz_min;
1341	else
1342		sz /= sizeof(*out_values);
1343
1344	count = sz;
1345	while (count--)
1346		*out_values++ = be32_to_cpup(val++);
1347
1348	return sz;
1349}
1350EXPORT_SYMBOL_GPL(of_property_read_variable_u32_array);
1351
1352/**
1353 * of_property_read_u64 - Find and read a 64 bit integer from a property
1354 * @np:		device node from which the property value is to be read.
1355 * @propname:	name of the property to be searched.
1356 * @out_value:	pointer to return value, modified only if return value is 0.
1357 *
1358 * Search for a property in a device node and read a 64-bit value from
1359 * it. Returns 0 on success, -EINVAL if the property does not exist,
1360 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1361 * property data isn't large enough.
1362 *
1363 * The out_value is modified only if a valid u64 value can be decoded.
1364 */
1365int of_property_read_u64(const struct device_node *np, const char *propname,
1366			 u64 *out_value)
1367{
1368	const __be32 *val = of_find_property_value_of_size(np, propname,
1369						sizeof(*out_value),
1370						0,
1371						NULL);
1372
1373	if (IS_ERR(val))
1374		return PTR_ERR(val);
1375
1376	*out_value = of_read_number(val, 2);
1377	return 0;
1378}
1379EXPORT_SYMBOL_GPL(of_property_read_u64);
1380
1381/**
1382 * of_property_read_variable_u64_array - Find and read an array of 64 bit
1383 * integers from a property, with bounds on the minimum and maximum array size.
1384 *
1385 * @np:		device node from which the property value is to be read.
1386 * @propname:	name of the property to be searched.
1387 * @out_values:	pointer to return value, modified only if return value is 0.
1388 * @sz_min:	minimum number of array elements to read
1389 * @sz_max:	maximum number of array elements to read, if zero there is no
1390 *		upper limit on the number of elements in the dts entry but only
1391 *		sz_min will be read.
1392 *
1393 * Search for a property in a device node and read 64-bit value(s) from
1394 * it. Returns number of elements read on success, -EINVAL if the property
1395 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
1396 * if the property data is smaller than sz_min or longer than sz_max.
1397 *
1398 * The out_values is modified only if a valid u64 value can be decoded.
1399 */
1400int of_property_read_variable_u64_array(const struct device_node *np,
1401			       const char *propname, u64 *out_values,
1402			       size_t sz_min, size_t sz_max)
1403{
1404	size_t sz, count;
1405	const __be32 *val = of_find_property_value_of_size(np, propname,
1406						(sz_min * sizeof(*out_values)),
1407						(sz_max * sizeof(*out_values)),
1408						&sz);
1409
1410	if (IS_ERR(val))
1411		return PTR_ERR(val);
1412
1413	if (!sz_max)
1414		sz = sz_min;
1415	else
1416		sz /= sizeof(*out_values);
1417
1418	count = sz;
1419	while (count--) {
1420		*out_values++ = of_read_number(val, 2);
1421		val += 2;
1422	}
1423
1424	return sz;
1425}
1426EXPORT_SYMBOL_GPL(of_property_read_variable_u64_array);
1427
1428/**
1429 * of_property_read_string - Find and read a string from a property
1430 * @np:		device node from which the property value is to be read.
1431 * @propname:	name of the property to be searched.
1432 * @out_string:	pointer to null terminated return string, modified only if
1433 *		return value is 0.
1434 *
1435 * Search for a property in a device tree node and retrieve a null
1436 * terminated string value (pointer to data, not a copy). Returns 0 on
1437 * success, -EINVAL if the property does not exist, -ENODATA if property
1438 * does not have a value, and -EILSEQ if the string is not null-terminated
1439 * within the length of the property data.
1440 *
1441 * The out_string pointer is modified only if a valid string can be decoded.
1442 */
1443int of_property_read_string(const struct device_node *np, const char *propname,
1444				const char **out_string)
1445{
1446	const struct property *prop = of_find_property(np, propname, NULL);
1447	if (!prop)
1448		return -EINVAL;
1449	if (!prop->value)
1450		return -ENODATA;
1451	if (strnlen(prop->value, prop->length) >= prop->length)
1452		return -EILSEQ;
1453	*out_string = prop->value;
1454	return 0;
1455}
1456EXPORT_SYMBOL_GPL(of_property_read_string);
1457
1458/**
1459 * of_property_match_string() - Find string in a list and return index
1460 * @np: pointer to node containing string list property
1461 * @propname: string list property name
1462 * @string: pointer to string to search for in string list
1463 *
1464 * This function searches a string list property and returns the index
1465 * of a specific string value.
1466 */
1467int of_property_match_string(const struct device_node *np, const char *propname,
1468			     const char *string)
1469{
1470	const struct property *prop = of_find_property(np, propname, NULL);
1471	size_t l;
1472	int i;
1473	const char *p, *end;
1474
1475	if (!prop)
1476		return -EINVAL;
1477	if (!prop->value)
1478		return -ENODATA;
1479
1480	p = prop->value;
1481	end = p + prop->length;
1482
1483	for (i = 0; p < end; i++, p += l) {
1484		l = strnlen(p, end - p) + 1;
1485		if (p + l > end)
1486			return -EILSEQ;
1487		pr_debug("comparing %s with %s\n", string, p);
1488		if (strcmp(string, p) == 0)
1489			return i; /* Found it; return index */
1490	}
1491	return -ENODATA;
1492}
1493EXPORT_SYMBOL_GPL(of_property_match_string);
1494
1495/**
1496 * of_property_read_string_helper() - Utility helper for parsing string properties
1497 * @np:		device node from which the property value is to be read.
1498 * @propname:	name of the property to be searched.
1499 * @out_strs:	output array of string pointers.
1500 * @sz:		number of array elements to read.
1501 * @skip:	Number of strings to skip over at beginning of list.
1502 *
1503 * Don't call this function directly. It is a utility helper for the
1504 * of_property_read_string*() family of functions.
1505 */
1506int of_property_read_string_helper(const struct device_node *np,
1507				   const char *propname, const char **out_strs,
1508				   size_t sz, int skip)
1509{
1510	const struct property *prop = of_find_property(np, propname, NULL);
1511	int l = 0, i = 0;
1512	const char *p, *end;
1513
1514	if (!prop)
1515		return -EINVAL;
1516	if (!prop->value)
1517		return -ENODATA;
1518	p = prop->value;
1519	end = p + prop->length;
1520
1521	for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
1522		l = strnlen(p, end - p) + 1;
1523		if (p + l > end)
1524			return -EILSEQ;
1525		if (out_strs && i >= skip)
1526			*out_strs++ = p;
1527	}
1528	i -= skip;
1529	return i <= 0 ? -ENODATA : i;
1530}
1531EXPORT_SYMBOL_GPL(of_property_read_string_helper);
1532
1533void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1534{
1535	int i;
1536	printk("%s %s", msg, of_node_full_name(args->np));
1537	for (i = 0; i < args->args_count; i++) {
1538		const char delim = i ? ',' : ':';
1539
1540		pr_cont("%c%08x", delim, args->args[i]);
1541	}
1542	pr_cont("\n");
1543}
1544
1545int of_phandle_iterator_init(struct of_phandle_iterator *it,
1546		const struct device_node *np,
1547		const char *list_name,
1548		const char *cells_name,
1549		int cell_count)
1550{
1551	const __be32 *list;
1552	int size;
1553
1554	memset(it, 0, sizeof(*it));
 
1555
 
1556	list = of_get_property(np, list_name, &size);
1557	if (!list)
1558		return -ENOENT;
 
1559
1560	it->cells_name = cells_name;
1561	it->cell_count = cell_count;
1562	it->parent = np;
1563	it->list_end = list + size / sizeof(*list);
1564	it->phandle_end = list;
1565	it->cur = list;
1566
1567	return 0;
1568}
1569
1570int of_phandle_iterator_next(struct of_phandle_iterator *it)
1571{
1572	uint32_t count = 0;
1573
1574	if (it->node) {
1575		of_node_put(it->node);
1576		it->node = NULL;
1577	}
1578
1579	if (!it->cur || it->phandle_end >= it->list_end)
1580		return -ENOENT;
1581
1582	it->cur = it->phandle_end;
1583
1584	/* If phandle is 0, then it is an empty entry with no arguments. */
1585	it->phandle = be32_to_cpup(it->cur++);
1586
1587	if (it->phandle) {
1588
1589		/*
1590		 * Find the provider node and parse the #*-cells property to
1591		 * determine the argument length.
1592		 */
1593		it->node = of_find_node_by_phandle(it->phandle);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1594
1595		if (it->cells_name) {
1596			if (!it->node) {
1597				pr_err("%s: could not find phandle\n",
1598				       it->parent->full_name);
1599				goto err;
 
 
 
 
 
1600			}
1601
1602			if (of_property_read_u32(it->node, it->cells_name,
1603						 &count)) {
1604				pr_err("%s: could not get %s for %s\n",
1605				       it->parent->full_name,
1606				       it->cells_name,
1607				       it->node->full_name);
 
1608				goto err;
1609			}
1610		} else {
1611			count = it->cell_count;
1612		}
1613
1614		/*
1615		 * Make sure that the arguments actually fit in the remaining
1616		 * property data length
1617		 */
1618		if (it->cur + count > it->list_end) {
1619			pr_err("%s: arguments longer than property\n",
1620			       it->parent->full_name);
1621			goto err;
1622		}
1623	}
1624
1625	it->phandle_end = it->cur + count;
1626	it->cur_count = count;
1627
1628	return 0;
1629
1630err:
1631	if (it->node) {
1632		of_node_put(it->node);
1633		it->node = NULL;
1634	}
1635
1636	return -EINVAL;
1637}
1638
1639int of_phandle_iterator_args(struct of_phandle_iterator *it,
1640			     uint32_t *args,
1641			     int size)
1642{
1643	int i, count;
1644
1645	count = it->cur_count;
1646
1647	if (WARN_ON(size < count))
1648		count = size;
1649
1650	for (i = 0; i < count; i++)
1651		args[i] = be32_to_cpup(it->cur++);
1652
1653	return count;
1654}
1655
1656static int __of_parse_phandle_with_args(const struct device_node *np,
1657					const char *list_name,
1658					const char *cells_name,
1659					int cell_count, int index,
1660					struct of_phandle_args *out_args)
1661{
1662	struct of_phandle_iterator it;
1663	int rc, cur_index = 0;
1664
1665	/* Loop over the phandles until all the requested entry is found */
1666	of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1667		/*
1668		 * All of the error cases bail out of the loop, so at
1669		 * this point, the parsing is successful. If the requested
1670		 * index matches, then fill the out_args structure and return,
1671		 * or return -ENOENT for an empty entry.
1672		 */
1673		rc = -ENOENT;
1674		if (cur_index == index) {
1675			if (!it.phandle)
1676				goto err;
1677
1678			if (out_args) {
1679				int c;
1680
1681				c = of_phandle_iterator_args(&it,
1682							     out_args->args,
1683							     MAX_PHANDLE_ARGS);
1684				out_args->np = it.node;
1685				out_args->args_count = c;
1686			} else {
1687				of_node_put(it.node);
1688			}
1689
1690			/* Found it! return success */
1691			return 0;
1692		}
1693
 
 
 
1694		cur_index++;
1695	}
1696
1697	/*
1698	 * Unlock node before returning result; will be one of:
1699	 * -ENOENT : index is for empty phandle
1700	 * -EINVAL : parsing error on data
 
1701	 */
1702
1703 err:
1704	of_node_put(it.node);
 
1705	return rc;
1706}
1707
1708/**
1709 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1710 * @np: Pointer to device node holding phandle property
1711 * @phandle_name: Name of property holding a phandle value
1712 * @index: For properties holding a table of phandles, this is the index into
1713 *         the table
1714 *
1715 * Returns the device_node pointer with refcount incremented.  Use
1716 * of_node_put() on it when done.
1717 */
1718struct device_node *of_parse_phandle(const struct device_node *np,
1719				     const char *phandle_name, int index)
1720{
1721	struct of_phandle_args args;
1722
1723	if (index < 0)
1724		return NULL;
1725
1726	if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1727					 index, &args))
1728		return NULL;
1729
1730	return args.np;
1731}
1732EXPORT_SYMBOL(of_parse_phandle);
1733
1734/**
1735 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1736 * @np:		pointer to a device tree node containing a list
1737 * @list_name:	property name that contains a list
1738 * @cells_name:	property name that specifies phandles' arguments count
1739 * @index:	index of a phandle to parse out
1740 * @out_args:	optional pointer to output arguments structure (will be filled)
1741 *
1742 * This function is useful to parse lists of phandles and their arguments.
1743 * Returns 0 on success and fills out_args, on error returns appropriate
1744 * errno value.
1745 *
1746 * Caller is responsible to call of_node_put() on the returned out_args->np
1747 * pointer.
1748 *
1749 * Example:
1750 *
1751 * phandle1: node1 {
1752 *	#list-cells = <2>;
1753 * }
1754 *
1755 * phandle2: node2 {
1756 *	#list-cells = <1>;
1757 * }
1758 *
1759 * node3 {
1760 *	list = <&phandle1 1 2 &phandle2 3>;
1761 * }
1762 *
1763 * To get a device_node of the `node2' node you may call this:
1764 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1765 */
1766int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1767				const char *cells_name, int index,
1768				struct of_phandle_args *out_args)
1769{
1770	if (index < 0)
1771		return -EINVAL;
1772	return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1773					    index, out_args);
1774}
1775EXPORT_SYMBOL(of_parse_phandle_with_args);
1776
1777/**
1778 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1779 * @np:		pointer to a device tree node containing a list
1780 * @list_name:	property name that contains a list
1781 * @cell_count: number of argument cells following the phandle
1782 * @index:	index of a phandle to parse out
1783 * @out_args:	optional pointer to output arguments structure (will be filled)
1784 *
1785 * This function is useful to parse lists of phandles and their arguments.
1786 * Returns 0 on success and fills out_args, on error returns appropriate
1787 * errno value.
1788 *
1789 * Caller is responsible to call of_node_put() on the returned out_args->np
1790 * pointer.
1791 *
1792 * Example:
1793 *
1794 * phandle1: node1 {
1795 * }
1796 *
1797 * phandle2: node2 {
1798 * }
1799 *
1800 * node3 {
1801 *	list = <&phandle1 0 2 &phandle2 2 3>;
1802 * }
1803 *
1804 * To get a device_node of the `node2' node you may call this:
1805 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1806 */
1807int of_parse_phandle_with_fixed_args(const struct device_node *np,
1808				const char *list_name, int cell_count,
1809				int index, struct of_phandle_args *out_args)
1810{
1811	if (index < 0)
1812		return -EINVAL;
1813	return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1814					   index, out_args);
1815}
1816EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1817
1818/**
1819 * of_count_phandle_with_args() - Find the number of phandles references in a property
1820 * @np:		pointer to a device tree node containing a list
1821 * @list_name:	property name that contains a list
1822 * @cells_name:	property name that specifies phandles' arguments count
1823 *
1824 * Returns the number of phandle + argument tuples within a property. It
1825 * is a typical pattern to encode a list of phandle and variable
1826 * arguments into a single property. The number of arguments is encoded
1827 * by a property in the phandle-target node. For example, a gpios
1828 * property would contain a list of GPIO specifies consisting of a
1829 * phandle and 1 or more arguments. The number of arguments are
1830 * determined by the #gpio-cells property in the node pointed to by the
1831 * phandle.
1832 */
1833int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1834				const char *cells_name)
1835{
1836	struct of_phandle_iterator it;
1837	int rc, cur_index = 0;
1838
1839	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, 0);
1840	if (rc)
1841		return rc;
1842
1843	while ((rc = of_phandle_iterator_next(&it)) == 0)
1844		cur_index += 1;
1845
1846	if (rc != -ENOENT)
1847		return rc;
1848
1849	return cur_index;
1850}
1851EXPORT_SYMBOL(of_count_phandle_with_args);
1852
1853/**
1854 * __of_add_property - Add a property to a node without lock operations
1855 */
1856int __of_add_property(struct device_node *np, struct property *prop)
1857{
1858	struct property **next;
1859
1860	prop->next = NULL;
1861	next = &np->properties;
1862	while (*next) {
1863		if (strcmp(prop->name, (*next)->name) == 0)
1864			/* duplicate ! don't insert it */
1865			return -EEXIST;
1866
1867		next = &(*next)->next;
1868	}
1869	*next = prop;
1870
1871	return 0;
1872}
1873
1874/**
1875 * of_add_property - Add a property to a node
1876 */
1877int of_add_property(struct device_node *np, struct property *prop)
1878{
1879	unsigned long flags;
1880	int rc;
1881
1882	mutex_lock(&of_mutex);
1883
1884	raw_spin_lock_irqsave(&devtree_lock, flags);
1885	rc = __of_add_property(np, prop);
1886	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1887
1888	if (!rc)
1889		__of_add_property_sysfs(np, prop);
1890
1891	mutex_unlock(&of_mutex);
1892
1893	if (!rc)
1894		of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1895
1896	return rc;
1897}
1898
1899int __of_remove_property(struct device_node *np, struct property *prop)
1900{
1901	struct property **next;
1902
1903	for (next = &np->properties; *next; next = &(*next)->next) {
1904		if (*next == prop)
1905			break;
1906	}
1907	if (*next == NULL)
1908		return -ENODEV;
1909
1910	/* found the node */
1911	*next = prop->next;
1912	prop->next = np->deadprops;
1913	np->deadprops = prop;
1914
1915	return 0;
1916}
1917
1918void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
1919{
1920	sysfs_remove_bin_file(&np->kobj, &prop->attr);
1921	kfree(prop->attr.attr.name);
1922}
1923
1924void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
1925{
1926	if (!IS_ENABLED(CONFIG_SYSFS))
1927		return;
1928
1929	/* at early boot, bail here and defer setup to of_init() */
1930	if (of_kset && of_node_is_attached(np))
1931		__of_sysfs_remove_bin_file(np, prop);
1932}
1933
1934/**
1935 * of_remove_property - Remove a property from a node.
1936 *
1937 * Note that we don't actually remove it, since we have given out
1938 * who-knows-how-many pointers to the data using get-property.
1939 * Instead we just move the property to the "dead properties"
1940 * list, so it won't be found any more.
1941 */
1942int of_remove_property(struct device_node *np, struct property *prop)
1943{
1944	unsigned long flags;
1945	int rc;
1946
1947	if (!prop)
1948		return -ENODEV;
1949
1950	mutex_lock(&of_mutex);
1951
1952	raw_spin_lock_irqsave(&devtree_lock, flags);
1953	rc = __of_remove_property(np, prop);
1954	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1955
1956	if (!rc)
1957		__of_remove_property_sysfs(np, prop);
1958
1959	mutex_unlock(&of_mutex);
1960
1961	if (!rc)
1962		of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1963
1964	return rc;
1965}
1966
1967int __of_update_property(struct device_node *np, struct property *newprop,
1968		struct property **oldpropp)
1969{
1970	struct property **next, *oldprop;
1971
1972	for (next = &np->properties; *next; next = &(*next)->next) {
1973		if (of_prop_cmp((*next)->name, newprop->name) == 0)
1974			break;
1975	}
1976	*oldpropp = oldprop = *next;
1977
1978	if (oldprop) {
1979		/* replace the node */
1980		newprop->next = oldprop->next;
1981		*next = newprop;
1982		oldprop->next = np->deadprops;
1983		np->deadprops = oldprop;
1984	} else {
1985		/* new node */
1986		newprop->next = NULL;
1987		*next = newprop;
1988	}
1989
1990	return 0;
1991}
1992
1993void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
1994		struct property *oldprop)
1995{
1996	if (!IS_ENABLED(CONFIG_SYSFS))
1997		return;
1998
1999	/* At early boot, bail out and defer setup to of_init() */
2000	if (!of_kset)
2001		return;
2002
2003	if (oldprop)
2004		__of_sysfs_remove_bin_file(np, oldprop);
2005	__of_add_property_sysfs(np, newprop);
2006}
2007
2008/*
2009 * of_update_property - Update a property in a node, if the property does
2010 * not exist, add it.
2011 *
2012 * Note that we don't actually remove it, since we have given out
2013 * who-knows-how-many pointers to the data using get-property.
2014 * Instead we just move the property to the "dead properties" list,
2015 * and add the new property to the property list
2016 */
2017int of_update_property(struct device_node *np, struct property *newprop)
2018{
2019	struct property *oldprop;
2020	unsigned long flags;
2021	int rc;
2022
2023	if (!newprop->name)
2024		return -EINVAL;
2025
2026	mutex_lock(&of_mutex);
2027
2028	raw_spin_lock_irqsave(&devtree_lock, flags);
2029	rc = __of_update_property(np, newprop, &oldprop);
2030	raw_spin_unlock_irqrestore(&devtree_lock, flags);
2031
2032	if (!rc)
2033		__of_update_property_sysfs(np, newprop, oldprop);
2034
2035	mutex_unlock(&of_mutex);
2036
2037	if (!rc)
2038		of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
2039
2040	return rc;
2041}
2042
2043static void of_alias_add(struct alias_prop *ap, struct device_node *np,
2044			 int id, const char *stem, int stem_len)
2045{
2046	ap->np = np;
2047	ap->id = id;
2048	strncpy(ap->stem, stem, stem_len);
2049	ap->stem[stem_len] = 0;
2050	list_add_tail(&ap->link, &aliases_lookup);
2051	pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
2052		 ap->alias, ap->stem, ap->id, of_node_full_name(np));
2053}
2054
2055/**
2056 * of_alias_scan - Scan all properties of the 'aliases' node
2057 *
2058 * The function scans all the properties of the 'aliases' node and populates
2059 * the global lookup table with the properties.  It returns the
2060 * number of alias properties found, or an error code in case of failure.
2061 *
2062 * @dt_alloc:	An allocator that provides a virtual address to memory
2063 *		for storing the resulting tree
2064 */
2065void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
2066{
2067	struct property *pp;
2068
2069	of_aliases = of_find_node_by_path("/aliases");
2070	of_chosen = of_find_node_by_path("/chosen");
2071	if (of_chosen == NULL)
2072		of_chosen = of_find_node_by_path("/chosen@0");
2073
2074	if (of_chosen) {
2075		/* linux,stdout-path and /aliases/stdout are for legacy compatibility */
2076		const char *name = of_get_property(of_chosen, "stdout-path", NULL);
2077		if (!name)
2078			name = of_get_property(of_chosen, "linux,stdout-path", NULL);
2079		if (IS_ENABLED(CONFIG_PPC) && !name)
2080			name = of_get_property(of_aliases, "stdout", NULL);
2081		if (name)
2082			of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
2083	}
2084
2085	if (!of_aliases)
2086		return;
2087
2088	for_each_property_of_node(of_aliases, pp) {
2089		const char *start = pp->name;
2090		const char *end = start + strlen(start);
2091		struct device_node *np;
2092		struct alias_prop *ap;
2093		int id, len;
2094
2095		/* Skip those we do not want to proceed */
2096		if (!strcmp(pp->name, "name") ||
2097		    !strcmp(pp->name, "phandle") ||
2098		    !strcmp(pp->name, "linux,phandle"))
2099			continue;
2100
2101		np = of_find_node_by_path(pp->value);
2102		if (!np)
2103			continue;
2104
2105		/* walk the alias backwards to extract the id and work out
2106		 * the 'stem' string */
2107		while (isdigit(*(end-1)) && end > start)
2108			end--;
2109		len = end - start;
2110
2111		if (kstrtoint(end, 10, &id) < 0)
2112			continue;
2113
2114		/* Allocate an alias_prop with enough space for the stem */
2115		ap = dt_alloc(sizeof(*ap) + len + 1, 4);
2116		if (!ap)
2117			continue;
2118		memset(ap, 0, sizeof(*ap) + len + 1);
2119		ap->alias = start;
2120		of_alias_add(ap, np, id, start, len);
2121	}
2122}
2123
2124/**
2125 * of_alias_get_id - Get alias id for the given device_node
2126 * @np:		Pointer to the given device_node
2127 * @stem:	Alias stem of the given device_node
2128 *
2129 * The function travels the lookup table to get the alias id for the given
2130 * device_node and alias stem.  It returns the alias id if found.
2131 */
2132int of_alias_get_id(struct device_node *np, const char *stem)
2133{
2134	struct alias_prop *app;
2135	int id = -ENODEV;
2136
2137	mutex_lock(&of_mutex);
2138	list_for_each_entry(app, &aliases_lookup, link) {
2139		if (strcmp(app->stem, stem) != 0)
2140			continue;
2141
2142		if (np == app->np) {
2143			id = app->id;
2144			break;
2145		}
2146	}
2147	mutex_unlock(&of_mutex);
2148
2149	return id;
2150}
2151EXPORT_SYMBOL_GPL(of_alias_get_id);
2152
2153/**
2154 * of_alias_get_highest_id - Get highest alias id for the given stem
2155 * @stem:	Alias stem to be examined
2156 *
2157 * The function travels the lookup table to get the highest alias id for the
2158 * given alias stem.  It returns the alias id if found.
2159 */
2160int of_alias_get_highest_id(const char *stem)
2161{
2162	struct alias_prop *app;
2163	int id = -ENODEV;
2164
2165	mutex_lock(&of_mutex);
2166	list_for_each_entry(app, &aliases_lookup, link) {
2167		if (strcmp(app->stem, stem) != 0)
2168			continue;
2169
2170		if (app->id > id)
2171			id = app->id;
2172	}
2173	mutex_unlock(&of_mutex);
2174
2175	return id;
2176}
2177EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
2178
2179const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
2180			       u32 *pu)
2181{
2182	const void *curv = cur;
2183
2184	if (!prop)
2185		return NULL;
2186
2187	if (!cur) {
2188		curv = prop->value;
2189		goto out_val;
2190	}
2191
2192	curv += sizeof(*cur);
2193	if (curv >= prop->value + prop->length)
2194		return NULL;
2195
2196out_val:
2197	*pu = be32_to_cpup(curv);
2198	return curv;
2199}
2200EXPORT_SYMBOL_GPL(of_prop_next_u32);
2201
2202const char *of_prop_next_string(struct property *prop, const char *cur)
2203{
2204	const void *curv = cur;
2205
2206	if (!prop)
2207		return NULL;
2208
2209	if (!cur)
2210		return prop->value;
2211
2212	curv += strlen(cur) + 1;
2213	if (curv >= prop->value + prop->length)
2214		return NULL;
2215
2216	return curv;
2217}
2218EXPORT_SYMBOL_GPL(of_prop_next_string);
2219
2220/**
2221 * of_console_check() - Test and setup console for DT setup
2222 * @dn - Pointer to device node
2223 * @name - Name to use for preferred console without index. ex. "ttyS"
2224 * @index - Index to use for preferred console.
2225 *
2226 * Check if the given device node matches the stdout-path property in the
2227 * /chosen node. If it does then register it as the preferred console and return
2228 * TRUE. Otherwise return FALSE.
2229 */
2230bool of_console_check(struct device_node *dn, char *name, int index)
2231{
2232	if (!dn || dn != of_stdout || console_set_on_cmdline)
2233		return false;
2234	return !add_preferred_console(name, index,
2235				      kstrdup(of_stdout_options, GFP_KERNEL));
2236}
2237EXPORT_SYMBOL_GPL(of_console_check);
2238
2239/**
2240 *	of_find_next_cache_node - Find a node's subsidiary cache
2241 *	@np:	node of type "cpu" or "cache"
2242 *
2243 *	Returns a node pointer with refcount incremented, use
2244 *	of_node_put() on it when done.  Caller should hold a reference
2245 *	to np.
2246 */
2247struct device_node *of_find_next_cache_node(const struct device_node *np)
2248{
2249	struct device_node *child;
2250	const phandle *handle;
2251
2252	handle = of_get_property(np, "l2-cache", NULL);
2253	if (!handle)
2254		handle = of_get_property(np, "next-level-cache", NULL);
2255
2256	if (handle)
2257		return of_find_node_by_phandle(be32_to_cpup(handle));
2258
2259	/* OF on pmac has nodes instead of properties named "l2-cache"
2260	 * beneath CPU nodes.
2261	 */
2262	if (!strcmp(np->type, "cpu"))
2263		for_each_child_of_node(np, child)
2264			if (!strcmp(child->type, "cache"))
2265				return child;
2266
2267	return NULL;
2268}
2269
2270/**
2271 * of_graph_parse_endpoint() - parse common endpoint node properties
2272 * @node: pointer to endpoint device_node
2273 * @endpoint: pointer to the OF endpoint data structure
2274 *
2275 * The caller should hold a reference to @node.
2276 */
2277int of_graph_parse_endpoint(const struct device_node *node,
2278			    struct of_endpoint *endpoint)
2279{
2280	struct device_node *port_node = of_get_parent(node);
2281
2282	WARN_ONCE(!port_node, "%s(): endpoint %s has no parent node\n",
2283		  __func__, node->full_name);
2284
2285	memset(endpoint, 0, sizeof(*endpoint));
2286
2287	endpoint->local_node = node;
2288	/*
2289	 * It doesn't matter whether the two calls below succeed.
2290	 * If they don't then the default value 0 is used.
2291	 */
2292	of_property_read_u32(port_node, "reg", &endpoint->port);
2293	of_property_read_u32(node, "reg", &endpoint->id);
2294
2295	of_node_put(port_node);
2296
2297	return 0;
2298}
2299EXPORT_SYMBOL(of_graph_parse_endpoint);
2300
2301/**
2302 * of_graph_get_port_by_id() - get the port matching a given id
2303 * @parent: pointer to the parent device node
2304 * @id: id of the port
2305 *
2306 * Return: A 'port' node pointer with refcount incremented. The caller
2307 * has to use of_node_put() on it when done.
2308 */
2309struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
2310{
2311	struct device_node *node, *port;
2312
2313	node = of_get_child_by_name(parent, "ports");
2314	if (node)
2315		parent = node;
2316
2317	for_each_child_of_node(parent, port) {
2318		u32 port_id = 0;
2319
2320		if (of_node_cmp(port->name, "port") != 0)
2321			continue;
2322		of_property_read_u32(port, "reg", &port_id);
2323		if (id == port_id)
2324			break;
2325	}
2326
2327	of_node_put(node);
2328
2329	return port;
2330}
2331EXPORT_SYMBOL(of_graph_get_port_by_id);
2332
2333/**
2334 * of_graph_get_next_endpoint() - get next endpoint node
2335 * @parent: pointer to the parent device node
2336 * @prev: previous endpoint node, or NULL to get first
2337 *
2338 * Return: An 'endpoint' node pointer with refcount incremented. Refcount
2339 * of the passed @prev node is decremented.
2340 */
2341struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
2342					struct device_node *prev)
2343{
2344	struct device_node *endpoint;
2345	struct device_node *port;
2346
2347	if (!parent)
2348		return NULL;
2349
2350	/*
2351	 * Start by locating the port node. If no previous endpoint is specified
2352	 * search for the first port node, otherwise get the previous endpoint
2353	 * parent port node.
2354	 */
2355	if (!prev) {
2356		struct device_node *node;
2357
2358		node = of_get_child_by_name(parent, "ports");
2359		if (node)
2360			parent = node;
2361
2362		port = of_get_child_by_name(parent, "port");
2363		of_node_put(node);
2364
2365		if (!port) {
2366			pr_err("graph: no port node found in %s\n",
2367			       parent->full_name);
2368			return NULL;
2369		}
2370	} else {
2371		port = of_get_parent(prev);
2372		if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
2373			      __func__, prev->full_name))
2374			return NULL;
2375	}
2376
2377	while (1) {
2378		/*
2379		 * Now that we have a port node, get the next endpoint by
2380		 * getting the next child. If the previous endpoint is NULL this
2381		 * will return the first child.
2382		 */
2383		endpoint = of_get_next_child(port, prev);
2384		if (endpoint) {
2385			of_node_put(port);
2386			return endpoint;
2387		}
2388
2389		/* No more endpoints under this port, try the next one. */
2390		prev = NULL;
2391
2392		do {
2393			port = of_get_next_child(parent, port);
2394			if (!port)
2395				return NULL;
2396		} while (of_node_cmp(port->name, "port"));
2397	}
2398}
2399EXPORT_SYMBOL(of_graph_get_next_endpoint);
2400
2401/**
2402 * of_graph_get_endpoint_by_regs() - get endpoint node of specific identifiers
2403 * @parent: pointer to the parent device node
2404 * @port_reg: identifier (value of reg property) of the parent port node
2405 * @reg: identifier (value of reg property) of the endpoint node
2406 *
2407 * Return: An 'endpoint' node pointer which is identified by reg and at the same
2408 * is the child of a port node identified by port_reg. reg and port_reg are
2409 * ignored when they are -1.
2410 */
2411struct device_node *of_graph_get_endpoint_by_regs(
2412	const struct device_node *parent, int port_reg, int reg)
2413{
2414	struct of_endpoint endpoint;
2415	struct device_node *node = NULL;
 
 
 
 
 
 
2416
2417	for_each_endpoint_of_node(parent, node) {
2418		of_graph_parse_endpoint(node, &endpoint);
2419		if (((port_reg == -1) || (endpoint.port == port_reg)) &&
2420			((reg == -1) || (endpoint.id == reg)))
2421			return node;
 
 
2422	}
2423
2424	return NULL;
2425}
2426EXPORT_SYMBOL(of_graph_get_endpoint_by_regs);
2427
2428/**
2429 * of_graph_get_remote_port_parent() - get remote port's parent node
2430 * @node: pointer to a local endpoint device_node
2431 *
2432 * Return: Remote device node associated with remote endpoint node linked
2433 *	   to @node. Use of_node_put() on it when done.
2434 */
2435struct device_node *of_graph_get_remote_port_parent(
2436			       const struct device_node *node)
2437{
2438	struct device_node *np;
2439	unsigned int depth;
2440
2441	/* Get remote endpoint node. */
2442	np = of_parse_phandle(node, "remote-endpoint", 0);
2443
2444	/* Walk 3 levels up only if there is 'ports' node. */
2445	for (depth = 3; depth && np; depth--) {
2446		np = of_get_next_parent(np);
2447		if (depth == 2 && of_node_cmp(np->name, "ports"))
2448			break;
2449	}
2450	return np;
2451}
2452EXPORT_SYMBOL(of_graph_get_remote_port_parent);
2453
2454/**
2455 * of_graph_get_remote_port() - get remote port node
2456 * @node: pointer to a local endpoint device_node
2457 *
2458 * Return: Remote port node associated with remote endpoint node linked
2459 *	   to @node. Use of_node_put() on it when done.
2460 */
2461struct device_node *of_graph_get_remote_port(const struct device_node *node)
2462{
2463	struct device_node *np;
2464
2465	/* Get remote endpoint node. */
2466	np = of_parse_phandle(node, "remote-endpoint", 0);
2467	if (!np)
2468		return NULL;
2469	return of_get_next_parent(np);
2470}
2471EXPORT_SYMBOL(of_graph_get_remote_port);