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